In chemistry the suffix -ide is used to denote: (a) The non-metallic, or negative, element or radical in a binary compound; such as, oxide, sulphide or chloride. (b) A compound which is an anhydride; such as, glycolide or phthalide. (c) Any one of a series of derivatives; such as, indogenide, glucoside, etc. Research -ide
10Base2 is an Ethernetcabling specification. Data is transmitted at a rate of 10Mbps along coaxial thin-net cable to workstations along a trunk segment up to 607 feet, supporting 30 workstations per trunk to a maximum of 1024 workstations per network and a maximum network trunk length of 3035 feet.
10BaseT is an Ethernetcabling specification. Data is transmitted at a rate of 10Mbps along unshielded twisted pair cables (category 3 or better) to workstations a maximum of 328 feet from the hub. Each hub can connect twelve workstations, and twelve hubs can be connected to a central hub.
1vs Personal Internet Engine is both a Web and offline browser and a search engine for the IBMPC. The Web browser has a site structure viewer, page property checker, and dead link finder. The offline browser has a fast, multithread download processor, an easy and useful interface, and the ability to switch the specified download. The search engine can search for words, images, links, and HTML objects. Research 1vs Personal Internet Engine
2-chlorobuta-1,3-diene (chloroprene) is a colourless liquid chlorinated diene, with the formula CH2: CClCH:CH2. It is polymerised to make synthetic rubbers such as neoprene.
32bit fax is a computer program for the PC that integrates faxing into a Windows 95/98/NT environment. You can send faxes to individuals or groups, and design and save your own cover pages. 32bit Fax gives you control over the way you send and receive fax documents by providing a flexible event monitor. This program also includes a FaxBook that stores frequently used group and individual profiles. It supports a wide array of modems, printers, and paper sizes in both portrait and landscape modes. Many enhanced features for the FaxBook, cover pages, and a fax/modem tester are also included. Research 32bit Fax
3S is a full-featured 32-bit accounting software for Windows 95 and Windows NT.
3S includes: General ledger, Accounts receivable and Accounts payable: Powerful invoice/order entry system: Bank reconciliation: Automated cheque printing: The facility to design your own reports, business forms and financial statements. Export reports directly to Office97 and Corel WordPerfect Suite 7 and 8.
3S Accounting is a versatile accounting computerpackage for the PC designed for the small office/ home office (SOHO) market. 3S Accounting is full featured, easy to use and completely free. It includes a general ledger, accounts receivable, accounts payable, and an invoicing and order-entry system. Reports can be exported directly to MSOffice and Corel WordPerfect. Research 3S Accounting
3SI is an integrated accounting system for the IBMPC, designed for businesses that require inventory management and invoice/order entry features integrated with general-purpose accounting software. The context-sensitive Help feature and customisable desktop are designed so you can easily use 3SI's most advanced features. With 3SI, you can modify forms, such as cheques, invoices, purchase orders, statements of account, and financial statements, to suit your needs. Furthermore, each module has its own report generator so you can create the reports you need to manage your business. 3SI includes the following integrated modules: General Ledger, Accounts Receivable, Accounts Payable, Inventory, Invoicing, and Purchase Orders.
602Pro PC Suite is an integrated office suite for the PC that is compatible with Microsoft Office documents (types DOC/XLS) and is designed for computers running Windows 95, 98, and NT. The suite includes a word processor, spreadsheet, graphic editor, and visual desktop. It also includes a visual file manager that lets you preview documents before you open them. The suite offers processing of all types of information: text, numbers, pictures, mass fax/email communication, Web pages, and labels or bar codes. 602Pro Suite supports creation of templates with guides. It also offers a simple way of creating HTML documents, even if you don't have any knowledge of the language, and is designed to perform well even on slower PCs. This version includes increased support for DOC/XLS and HTML documents, the added ability to password protect documents, updated thumbnail printing features, and a photo album print option. Research 602Pro PC Suite
602Pro Personal Office Server is a personal communication centre for email, faxes, voice mail, and alphanumeric messaging. With this advanced email client, you can send and receive faxes from any Windows application, and also set up your computer as an answering machine. You can organize all of your communication by forwarding email, voice mail, and faxes from your home computer to your office email address. Let your email follow you wherever you go with your alphanumericcell phone or pager. Research 602Pro Personal Office Server
7-Zip is a free file archiver by Igor Pavlov, for the Windows operating systems distributed under the GNU LGP license. 7-Zip supports 7z, ZIP, RAR, CAB, ARJ, GZIP, BZIP2, TAR, CPIO, RPM and DEB compressed file formats enabling UnixTAR archives to be created and decompressed under Windows. 7-Zip is comprised of three clients modules: a plug in for Windows Explorer, a plug in for the FAR Manager, and a command line version.
In computing, an A/B box is a two-to-one manual switch box with either two inputs or two outputs, typically used to either connect two peripherals (such as monitors) to one computer or one peripheral (such as a printer) to two computers. Research A/B Box
In audio-engineering an A/D converter converts analog signals into digital signals. The analog signal is sampled every few milliseconds and its level is quantified into a digital word. The larger the digital word, the more accurate the representation of the analog value. Research A/D Converter
In computing, AAC (Advanced Audio Coding) is an audio compression technology that is part of the MPEG-2 standard. It provides a greater compression and superior sound quality than MP3, which is also part of the MPEG specification. AAC is available in three profiles: 'Main', 'Low Complexity' (LC) and 'Scaleable Sampling Rate' (SSR), with 'Main' providing the highest quality. Research AAC
Abaca or Manila Hemp, is a strong fibre yielded by the leaf-stalks of a kind of plantain (Musa textllis) which grows in the Indian Archipelago, and is cultivated in the Philippines. The outer fibres of the leafstalks are made into strong and durable ropes, the inner into various fine fabrics. Research Abaca
Abbreviated Dialling is pre-programming of a caller's phone system or long distance company's switch to recognise a 2- to 4-digit number as an abbreviation for a frequently dialled phone number, and automatically dial the whole number. Research Abbreviated Dialling
In computing, an abend is a procedure to halt a computer program prematurely, usually because of a program error or system fault. Abend is short for 'abnormal end'. Research Abend
In optics an aberration is a defect in the image formed by a lens or curved mirror. In chromatic
aberration the image formed by a lens, but not a mirror, has coloured fringes as a result of the different extent to which light of different colours is refracted by glass. It is corrected by using an achromaticlens. In spherical aberration, the rays from the object come to a focus in slightly different positions as a result of the curvature of the lens or mirror. For a mirror receiving light strictly parallel with its axis, this can be corrected by using a parabolic surface rather than a spherical surface. Spherical aberration in lenses is minimized by making both surfaces contribute equally to the ray deviations, and can (though with reduced image brightness) be reduced by the use of diaphragms to let light pass only through the centre part of the lens. In astronomy an aberration is the apparentdisplacement in the position of a star as a result of the earth's motion round the sun. Light appears to come from a point that is slightly displaced in the direction of the earth's motion. The angular displacement a = v/c, where v is the earth's orbitalvelocity and c is the speed of light. Aberration was discovered in 1728 by the English astronomer James Bradley and was the first observational proof that the Earth orbits the Sun.
In astronomy, aberration is a small periodical change of the position in the stars and other heavenly bodies, due to the combined effect of the motion of light and the motion of the observer; this is called annual aberration, when the observer's motion is that of the earth in its orbit, and daily or diurnal aberration, when of the earth on its axis; amounting when greatest, in the former case, to 20.4', and in the latter, to 0.3'. Planetary aberration is that due to the motion of light and the motion of the planet relative to the earth. In optics, aberration is the convergence to different foci, by a lens or mirror, of rays of light emanating from one and the same point, or the deviation of such rays from a single focus; called spherical aberration, when due to the spherical form of the lens or mirror, such form giving different foci for central and marginal rays; and chromatic aberration, when due to different refrangibilities of the coloured rays of the spectrum, those of each colour having a distinct focus. Research Aberration
An abiotic factor is a non-organic variable within the ecosystem, affecting the life of organisms. Examples of abiotic factors include temperature, light, and soil structure. Some
abiotic factors can be harmful to the environment such as when sulphur dioxide emissions from power stations react with water in the atmosphere to produce acidrain. Research Abiotic Factor
ABS or Acrylonitrile-Butadiene-Styrene, is an inexpensive, tough, thermoplastic polymer mass produced since the 1960's. ABS is rigid with moderate strength but with a tendency towards developing stress cracks. Commercially it is widely used in consumer goods, computer cases and in pipe fittings and automobiles. Research ABS
Absolute configuration is a way of denoting the absolute structure of an optical isomer. Two conventions are in use: The D-L convention relates the structure of the molecule to some reference molecule. In the case of sugars and similar compounds, the dextrorotatory form of glyceraldehyde was used. The rule is as follows. Write the structure of this molecule down with the asymmetric carbon in the centre, the -CHO group at the top, the -OH on the right, the -CH2OH at the bottom, and the -H on the left. Now imagine that the central carbonatom is at the centre of a tetrahedron with the four groups at the corners and that the -H and -OH come out of the paper and the -CHO and -CH2OH groups go into the paper. The resulting three-dimensional structure was taken to be that of d-glyceraldehyde and called D-glyceraldehyde. Any compound that contains an asymmetric carbonatom having this configuration belongs to the D-series. One having the opposite configuration belongs to the L-series. It is important to note that the prefixes D- and L- do not stand for dextrorotatory and laevorotatory (they are not the same as d- and l-).
In fact the arbitrary configuration assigned to D-glyceraldehyde is now known to be the correct one for the dextrorotatory form, although this was not known at the time. However, all D-compounds are not dextrorotatory. For instance, the acid obtained by oxidizing the -CHO group of glyceraldehyde is glyceric acid (1,2-dihydroxypropanoic acid). By convention, this belongs to the D-series, but it is in fact laevorotatory; i.e. its name can be written as D-glyceric acid or l-glyceric acid. To avoid confusion it is better to use + (for dextrorotatory) and - (for laevorotatory), as in D-(+)-glyceraldehyde and D-(-)-glyceric acid. The D-L convention can also be used with alpha amino acids. In this case the molecule is imagined as being viewed along the H-C bond between the hydrogen and the asymmetric carbonatom. If the clockwise order of the other three groups is -COOH, -R, -NH2, the amino acid belongs to the D-series; otherwise it belongs to the L-series. This is known as the CORN rule.
The R-S convention is a convention based on priority of groups attached to the chiral carbonatom. The order of priority is I, Br, Cl, SO3H, OCOCH3, OCH3, OH, NO2, NH2, COOCH3, CONH2, COCH3, CHO, CH2OH, C6H5, C2H5, CH3, H, with hydrogen being the lowest. The molecule is viewed with the group of lowest priority behind the chiral atom. If the clockwise arrangement of the other three groups is in descending priority, the compound belongs to the R-series; if the descending order is anticlockwise it is in the S-series. D-(+)-glyceraldehyde is R-(+)-glyceraldehyde. Research Absolute Configuration
Absolute Delay is the actual time taken for a signal to transit a telecommunications circuit from end to end; affected by the actual circuit length and the 'propagation constants' of the type of medium in use. Research Absolute Delay
In electronics, an absorber circuit is a combination of a resistor and a capacitor in series, connected across the terminals of a switch or other circuit-breaking device in an oscillatory circuit. Its function is to damp the circuit and thus to prevent sparking or arcing when the current is interrupted. Research Absorber Circuit
An absorptiometer is an instrument for the accurate measurement of the absorption and transmission of light by semi-transparent substances and used for the determination of turbidity, fluorimetry, etc. Research Absorptiometer
In chemistry absorption is the take up of a gas by a solid or liquid, or the take up of a liquid by a solid.
Absorption differs from adsorption in that the absorbed substance permeates the bulk of the absorbing substance. In physics the term absorption refers to the conversion of the energy of electromagnetic radiation, sound, streams of particles, etc., into other forms of energy on passing through a medium. A beam of light, for instance, passing through a medium, may lose intensity because of two effects: scattering of light out of the beam, and absorption of photons by atoms or molecules in the medium. When a photon is absorbed, there is a transition to an excited state. In biology the term absorption refers to the movement of fluid or a dissolved substance across a cellmembrane. In animals, for example, soluble food material is absorbed into the circulatory system through cells lining the alimentarycanal. In plants, water and mineral salts are absorbed from the soil by the roots. Research Absorption
In mechanics, an abutment is a fixed point or surface from which resistance or reaction is obtained, such as the cylinder head of a steam engine, the fulcrum of a lever, etc. Research Abutment
Abyssal plains are broad expanses of sea floor lying between three and six kilometres below sea level. Abyssal plains are found in all the major oceans, and they extend from bordering continental rises to mid-oceanic ridges. Underlain by outward-spreading, new oceanic crust extruded from ridges,
abyssal plains are covered in deep-sea sediments derived from continental slopes and floating microscopic marine organisms. The plains often are interrupted by chains of volcanic islands where plates ride over hot spots in the mantle, and by sea mounts originally formed in oceanic ridge areas. Research Abyssal Plain
The abyssal zone is the region of an ocean between 2000 and 6000 metres deep, lying between the bathyal zone above and the hadal zone below. The abyssal zone is too far from the surface for light to penetrate, and hence too far for photosynthesis to take place. Research Abyssal Zone
AC '97 (Audio Codec '97) is a specification for an audio system within personal computers developed in 1996 by, among others, Intel, Analog Devices and Creative Labs. AC '97 separates the analog and digital circuits, thereby reducing noise. Research AC '97
An accelerated graphics port (AGP) is a dedicated port developed by Intel, that links the graphics controller on a personal computer directly to the computer's memory, allowing data to be transferred directly between memory and the graphics adapter, rather than having to be fetched via the expansion bus. As a result AGP can handle at least twice the throughput of a standard PCI bus. Research Accelerated Graphics Port
An accelerating electrode is an electrode in an electron tube which is maintained at a positive potential with respect to the cathode and any other electrodes situated between the cathode and the
accelerating electrode, thus imparting acceleration to electrons in the direction away from the cathode. Although this definition includes the anode of the tube, the term is usually reserved for
accelerating electrodes other than the anode. Research Accelerating Electrode
An accelerometer is an apparatus, either mechanical or electromechanical, for measuring acceleration or deceleration - that is, the rate of increase or decrease in the velocity of a moving object.
Accelerometers are used to measure the efficiency of the braking systems on road and rail vehicles; those used in aircraft and spacecraft can determine accelerations in several directions simultaneously. There are also accelerometers for detecting vibrations in machinery. Research Accelerometer
In computing, an access arm or actuator arm, is a mechanical arm that moves the read/write head across the surface of a disk in a manner similar to a tonearm on a record player. The access arm is directed by instructions provided by the operating system to move the read/write head to a specific track on the disk. The rotation of the disk positions the read/write head over the required sector. Research Access Arm
Access Charge is a cost assessed to users for connection ability to the interexchange, interstate message tolltelephone networks of IEC's by the user's LEC, to send and receive calls beyond the immediate local exchange area. May be per minute fees levied on long distance companies, Subscriber Line Charges (SLCs) levied directly on regular local lines, fixed monthly fees for special telco circuits (i.e. WAL, DAL, T-1), or Special Access Surcharge (SAS) on special access circuits. Research Access Charge
In PBXs, an access code is a digit or digits dialled prior to dialling an outside call (most typically '9', or a digit entered on a feature phone set to activate functions like Call Forwarding or Conference Add-on (most typically '*' or '#') Research Access Code
In computing, an account is a login name and a password, perhaps a personal directory (certainly on a Unix system) and perhaps a shell (certainly on a Unix system) and perhaps personal settings for a graphical (window) environment. Research Account
Account & See Invoicing is a user-friendly invoicing program for the PC. It enables the user to quickly create invoices using the mouse or keyboard - use 'Matrix Prices' to charge different prices for the same goods. You can export all information and print mailing labels. Extensive reporting shows Account Ageing, Aged Debtors/ Delinquencies, Tax accounting plus in-depth Sales Ledger breakdowns. On-line context sensitive Help and free e-mail support are included. Research Account & See Invoicing
In PBXs, an account code is a code digit or digits a user must enter before or after a call is dialled, to establish accounting for the charges for the call. Research Account Code
In science, an accumulator is an apparatus by means of which energy or power can be stored, such as the cylinder or tank for storing water for hydraulic elevators, the secondary or a storage battery used for storing the energy of electrical charges, etc.
In computing, the accumulator is a hardware register in the CPU used to receive the results of operations performed by the arithmetic and logic unit (ALU). The accumulator register can often also be used to perform shifts and rotations on values. Research Accumulator
AceNotes is a notes manager for the IBMPC that you can use as your personal information manager and text editor. In AceNotes, notes are stored in a tree structure by which you can categorize your notes easily in whatever form you like. In this release, many new features have been added, including changing tree nodes' font and colour, auto URL detect, the ability to insert pictures, bookmark functions, file compression, auto file storage, password protection, and more. Research AceNotes
Acetaldehyde is a colourless liquid with a pungent, fruity odour. It is used primarily as a chemical intermediate, principally for the production of acetic acid, pyridine and pyridinebases, peracetic acid, pentaerythritol, butylene glycol, and chloral. It is used in the production of esters, particularly ethyl acetate and isobutyl acetate. It is also used in the synthesis of crotonaldehyde, flavour and fragrance acetals, acetaldehyde 1,1-dimethylhydrazone, acetaldehyde cyanohydrin, acetaldehyde oxime, and various acetic esters, paraldehyde, metaldehyde, polymers, and various halogenated derivatives. Acetaldehyde is used in denatured alcohol. In the past it was a chemical intermediate for 2-ethyl-1-butanol, glyoxal, acrolein, and acetaldehyde-aniline condensate. Acetaldehyde has been used in the manufacture of aniline dyes and synthetic rubber, to silvermirrors, and to hardengelatine fibres.
Acetaldehyde has been used in the production of polyvinyl acetal resins, in fuel compositions, and to inhibit mould growth on leather. It is also used in the manufacture of disinfectants, drugs, perfumes, explosives, lacquers, varnishes, photographic chemicals, phenolic and urea resins, rubber accelerators, antioxidants, and room air deodorisers. It is also a pesticide intermediate.
Acetaldehyde is a compound for the intended use as a flavouring agent and adjuvant. It is an important component of food flavourings added to milk products, baked goods, fruit juices, candy, desserts, and soft drinks; the concentration of acetaldehyde in food is usually up to .047%. It is an especially useful synthetic flavouring ingredient to impart orange, apple, and butter flavours, and is used in the manufacture of vinegar and yeast and as a fruit and fish preservative.
Acetaldehyde is a volatile and flammable liquid. It is miscible in water, alcohol, ether, benzene, gasoline, solvent, naphtha, toluene, xylene, turpentine, acetone, and other common organic solvents. It is a highly reactive compound that undergoes numerous condensation, addition, and polymerisation reactions. It is dangerous when exposed to heat or flame; it can react vigorously with oxidising material, acid anhydrides, alcohols, ketones, phenols, halogens, isocyanates, and strong alkalis and amines. It is also incompatible with acids, bases, alcohol, ammonia, amines, phenols, ketones, and hydrogen cyanide. It will polymerise readily in the presence of trace metals. Acetaldehyde can form unstable or explosive peroxides with exposure to the air. It may polymerise under the influence of air and heat, acids, or bases with potential of fire or explosion. It is polymerised violently by concentrated sulphuric acid. Rubber products decompose on contact with acetaldehyde, but it is not corrosive to most metals. It is also known as acetic aldehyde, ethanal, NCI-C56326, and ethyl aldehyde. Research Acetaldehyde
Acetate is a man-made cellulose fabric or yarn that was first created in Germany in 1869. Work on the fibre was continued by Swiss chemists Camille and Henri Dreyfus of Basle in the 1900s, but their research was interrupted by the outbreak of the Great War when acetate was used to make waterproof varnishes for French and British fabric-covered aeroplanes. In 1920 British Celanese Ltd made a commercially viable acetate fibre using the Dreyfus method.
Acetate has since been used to make lingerie, blouses, dresses and knitwear as well as other garments requiring lightweight, silky fabrics. Research Acetate
Acetates are salts of acetic acid. The acetates of most commercial or manufacturing importance are those of aluminium and iron, which are used in calico-printing; of copper, which as verdigris is used as a colour; and of lead, best known as sugar of lead. The acetates of potassium, sodium, and ammonium, of iron, zinc, and lead, and the acetate of morphia, are employed in medicine. Research Acetates
Acetic Acid is an acid produced by the oxidation of common alcohol, and of many other organic substances. Pure acetic acid has a very sour taste and pungent smell, burns the skin, and is poisonous. From freezing at ordinary temperatures (58 degrees or 59 degrees) it is known as glacial acetic acid. Vinegar is simply dilute acetic acid. Acetic acid is largely used in the arts, in medicine, and for domestic purposes. Research Acetic acid
Acetone is the simplest and most important of the ketones. It is a colourless liquid with a mildly pungent and somewhat aromatic odour. It is primarily used as a chemical intermediate and as a solvent for celluloseacetate and nitro-cellulose. It is used as a carrier for acetylene, and as a raw material for the chemical synthesis of a wide range of products such as ketene, methyl methacrylate, bisphenol A, diacetone alcohol, mesityl oxide, methyl isobutyl ketone, hexylene glycol, and isophorone.
Acetone is a mobile, flammable liquid that is miscible in all proportions with water and with organic solvents such as ether, methanol, ethyl alcohol, and esters. It is incompatible and reactive with oxidisers and acids. Containers of acetone may explode in a fire, producing poisonous gases. Acetone fires may be controlled with carbon dioxide or dry chemical extinguishers.
Acetone undergoes many condensation reactions; in the presence of an amine, or ammonia, various esters condense readily with acetone. Acetone is also known commercially as dimethyl ketone, methyl ketone, dimethylformaldehyde, ketone propane, and 2-propanone.
Acetone is formed in the humanblood when the body uses fat instead of glucose for energy. If
acetone forms, it usually means that the cells do not have enough insulin, or cannot use the insulin that is in the blood, to use glucose for energy. Acetone passes through the body into the urine. Someone with a lot of acetone in the body can have breath that smells fruity and is called '
acetone breath'.
Acetone is used in painting and decorating for scrubbing the surface of certain woods, such as cedar and teak, prior to painting them. Research Acetone
Acetylene is a highly inflammable gas of the hydrocarbon family used for welding and cutting metals. It was discovered by Berthelot. In 1862 Friedrich Wohler discovered that carbide of calcium treated with water produced lime and acetylene. In 1895 acetylene was cheaply produced on a commercial scale and subsequently was used for general lighting.
Acetylene is colourless, and has a rather pleasant ethereal smell when pure, but as ordinarily prepared it is not quite pure, containing small quantities of sulphuretted and phosphuretted hydrogen, and having a strong and disagreeable odour. It can be liquefied by cold and pressure, and may even be obtained in the solid form as a snow-like mass. It is one of the constituents of ordinary coal-gas, but is present in very small quantities. It burns readily, being ignited at a temperature below that at which coal-gas is ignited. If there is not a sufficient supply of air the flame is dull and very smoky, but when a proper burner is used acetylene gives a very white and brilliant flame, its illuminating power being far higher than that of coal-gas. It possesses properties that may render it dangerous in certain circumstances, and these have to be guarded against. The gas itself may be made to explode by (a) high temperature and great pressure, and (b) a detonation some little distance away, and in the liquid form the risk of explosion is so great that in Britain and elsewhere liquid acetylene is forbidden to be stored and used. When mixed with chlorine it explodes spontaneously. Like other combustible gases it forms an explosive mixture with air.
Acetylene has been known for a considerable time, and may be produced in various ways, but only in the late 19th century did it come into extensive use as an illuminant, and only since a cheap method of producing carbide of lime (calcium carbide) was discovered, the gas being readily prepared by bringing this substance into contact with water. Calcium carbide was manufactured by subjecting a mixture of coke and lime to the heat of an electric furnace, and when it is brought into contact with water the carbide is decomposed, and acetylene and lime or hydrate of lime are produced. To provide a supply of acetylene gas for lighting purposes various forms of generator were in use, and in these the carbide was either brought slowly into contact with the water, or the water was brought gradually into contact with the carbide, or the two was brought together at intervals and again separated. The gas had to be evolved at a low temperature, and under a low pressure, and in the absence of air. Before being used it had to be purified by passing it through suitable substances. A dry process of production was introduced in the late 19th century. Several kinds of burners and lamps were used, and portable lamps were quite common by 1900. Country mansions and such detached residences were often lighted by acetylene gas. A license was required to enable a person to keep more than 28 lbs. of calcium carbide stored in any building. Research Acetylene
The Acheson process is an industrial process for the manufacture of graphite by heating coke mixed with clay. The reaction involves the production of silicon carbide, which loses silicon at 4150°C to leave graphite. The process was patented in 1896 by the American inventor Edward Acheson. Research Acheson Process
In optics, achromatic refers to transmitting colourless light, that is, not decomposed into the primary colours, though having passed through a refracting medium. A single convex lens does not give an image free from the prismatic colours, because the rays of different colour making up white light are not equally refrangible, and thus do not all come to a focus together, the violet, for instance, being nearest the lens, the red farthest off. If such a lens of crown-glass, however, is combined with a concave lens of flint-glass - the curvatures of both being properly adjusted - as the two materials have somewhat different optical properties, the latter will neutralize the chromaticaberration of the former, and a satisfactory image will be produced. Telescopes, microscopes, etc, in which the glasses are thus composed are called achromatic. Research Achromatic
An acid is a chemical compound that reacts with metals to form salts by releasing hydrogen.
Their general properties are sour taste, the power of changing vegetable blues into reds, of evolving hydrogen in presence of magnesium, of decomposing chalk with effervescence, and of being in various degrees neutralized by alkalis. An acid has been defined as a compound of hydrogen, the whole or a part of which is replaceable by a metal when this is presented in the form of a hydroxide; being monobasic, dibasic, or tribasic, according to the number of replaceable hydrogen atoms in a molecule. Some acids also contain oxygen and these are called oxy-acids. Varying amounts of oxygen in an acid are reflected in its name ending -ous or -ic, and the salts formed from such acids are similarly named ending in -ite and -ate. Research Acid
Acierage is a former process by which an engraved copper-plate or an electrotype from an engraved plate of steel or copper has a film of iron deposited over its surface by electricity in order to protect the engraving from wear in printing. By this means an electrotype of a fine engraving, which, if printed directly from the copper, would not yield 500 good impress sions, can be made to yield 3000 or more, and when the film of iron becomes so worn as to reveal any part of the copper, it may be removed and a fresh coating deposited so that 20,000 good impressions may be made. Research Acierage
In telecommunications, ACK is the 'acknowledge' character in many data codes; used most commonly for an affirmative response of correct receipt. Research ACK
Ackerman geometry is an arrangement of the steering linkage of a wheeled vehicle to ensure that both near and off-side wheels roll tangentially when cornering. Research Ackerman Geometry
The Ackerman steer angle is the mean angle at which a pair of steered wheels needs to be set for the vehicle to follow a given path at low speed. Research Ackerman Steer Angle
Aconitine is an alkaloid extracted from monk's-hood and some other species of aconite. It is used medicinally, though it is a virulent poison. Research Aconitine
An acorn valve is a form of thermionic valve used at ultra-high frequencies, in which, by adopting very small dimensions and special constructions, the inter-electrode capacitances, lead inductances and transit time effects are greatly reduced. Research Acorn Valve
An acoustic coupler is means of connecting external devices to a telephone handset avoiding direct electrical connection; most commonly used for low-speed data terminals. Research Acoustic Coupler
Acoustic feedback is the return of acoustic energy from the output of a sound reproducing equipment, such as a microphone-amplifier-loudspeaker combination, to the input or to an intermediate stage, thereby causing the system to generate sustained oscillations which are manifested as continual howling. Research Acoustic Feedback
Acoustics is the experimental and theoretical science of sound and hearing, and especially the phenomena of sound in space, such as buildings.
Acoustics teaches the cause, nature, and phenomena of such vibrations of elastic
bodies as affect the organ of hearing; the manner in which sound is produced, its transmission through air and other media, the doctrine of reflected sound or echoes, the properties and effects of different sounds, including musical sounds or notes, and the structure and action of the organ of hearing, etc. The propagation of sound is analogous to that of light, both being due to vibrations which produce successive waves, and Isaac Newton was the first to show that its propagation through any medium depended upon the elasticity of that medium. Regarding the intensity, reflection, and refraction of sound, much the same rules apply as in light. In ordinary cases of hearing the vibrating medium is air, but all substances capable of vibrating may be employed to propagate and convey sound. When a bell is struck its vibrations are communicated to the particles of air surrounding it, and from these to particles outside them, until they reach the ear of the listener. The intensity of sound varies inversely as the square of the distance of the body sounding from the ear. Sound travels through the air at the rate of about 332 metres per second; through water at the rate of about 1433 metres.
Sounds may be musical or non-musical. A musical sound is caused by a regular series of exactly similar pulses succeeding each other at precisely equal intervals of time. If these conditions are not fulfilled the sound is a noise. Musical sounds are comparatively simple, and are combined to give pleasing sensations according to easy numerical relations. The loudness of a note depends on the degree to which it affects the ear; the pitch of a note depends on the number of vibrations to the second which produce the note; the timbre, quality, or character of a note depends on the body or bodies whose vibrations produce the sound, and is due to the form of the paths of vibrating particles. The gamut is a series of eight notes, which are called by the names Do, Re, Mi, Fa, Sol, La, Si, Do, and the numbers of vibrations which produce these notes are respectively proportional to 24, 27, 30, 32, 36, 40, 45, 48. The numerical value of the interval between any two notes is given by dividing one of the above numbers corresponding to the higher note by the number corresponding to the lower note. The intervals from Do to each of the others are called a second, a major third, a fourth, a, fifth, a sixth, a seventh, and an octave respectively. The interval from La to Do is a minor third. An interval of nine eights is a major tone; ten ninths is a minor tone; sixteen fifteenths is called a limma.
Acrylamide is an odourless, free-flowing white crystalline used as a chemical intermediate in the production and synthesis of polyacrylamides. These high-molecular weight polymers can be modified to develop non-ionic, anionic, or cationic properties for specific uses. The principle end use of
acrylamide is in water-soluble polymers used as additives for water treatment, enhanced oil recovery, flocculants, papermaking aids, thickeners, soil conditioning agents, sewage and waste treatment, ore processing, and permanent press fabrics.
Acrylamide is also used in the synthesis of dyes, in copolymers for contact lenses, and the construction of damfoundations, tunnels, and sewers. The largest use for polyacrylamide is in treating municipal drinking water and wastewater. The polymer is also used to remove suspended solids from industrial wastewater before discharge, reuse, or disposal.
Acrylamides also find use in oil-drilling processes to control fluid losses. In the pulp and paper industry, polyacrylamides are used as binders and retention aids for fibres and to retain pigments on paper fibres.
Acrylamide is a soil stabiliser and also finds use in foundry operations to facilitate free sand flow into moulds. Home appliances, building materials, and automotive parts are coated with acrylamide resins and thermosetting acrylics. Acrylamides are formulated in cosmetics and soap preparations as thickeners and in dental fixtures, hair grooming preparations, and pre-shave lotions. Minor uses of acrylamide are as latex thickeners, emulsion stabilisers for printing inks, gelling agents for explosives, binders in adhesives and adhesive tape, in the production of diazo compounds, and for gel chromatography and electrophoresis.
Acrylamide occurs in crystalline form and in aqueous solution. It is soluble in water, methanol, ethanol, dimethyl ether, and acetone; it is insoluble in benzene and heptane. The monomer readily polymerises at the melting point or under ultraviolet light. Solid acrylamide is stable at room temperature, but may polymerise violently when melted or in contact with oxidising agents such as chlorine dioxide and bromine. When heated to decomposition, acrylamide emits a poisonous gas, acrid fumes, and NOx. If heating to high temperatures, acrylamide can explode. Acrylamide is also known as
acrylamide monomer, acrylic amide, propenamide, and 2-propenamide. Research Acrylamide
An acrylic resin is a synthetic resins made by polymerising esters or other derivatives of acrylic acid (propenoic acid). Examples of acrylic resins are Acrilan and Perspex. Research Acrylic Resins
Actinism is the property of those rays of light which produce chemical changes, as in photography, in contradistinction to the light rays and heat rays. The actinic property or force begins among the green rays, is strongest in the violet rays, and extends a long way beyond the visible spectrum. Research Actinism
Active Editor is a WYSIWYG visual HTML editor for the Windows operating system that enables you to focus on your Web page content while it takes care of producing the HTML syntax. Research Active Editor
ActiveX is a technology developed by Microsoft for sharing information among different applications.
ActiveX is an outgrowth of two other Microsoft technologies: OLE (Object Linking and Embedding) and COM (Component Object Model). ActiveX supports features that enable it to take advantage of the Internet. For example, an
ActiveX control can be automatically downloaded and executed by a Web browser.
ActiveX is not a programming language, but rather a set of rules for how applications should share information. Programmers can develop
ActiveX controls in a variety of languages, including C , C++, Visual Basic, and Java. An ActiveX control is similar to a Java applet. Unlike Java applets, however, ActiveX controls have full access to the Windows operating system. This gives them more power than Java applets, but also the risk that the control may damage software on your machine. To control this risk, Microsoft developed a registration system so that browsers can identify and authenticate an ActiveX control before downloading it. Another difference between Java applets and ActiveX controls is that Java applets run on all platforms, whereas ActiveX controls are currently limited to Windows environments. Related to ActiveX is the scripting language VBScript that enables Web authors to embed interactive elements in HTML documents. Just as JavaScript is similar to Java, so VBScript is similar to Visual Basic. Currently, Microsoft's Web browser, Internet Explorer, supports Java, JavaScript, and ActiveX, whereas Netscape's Navigator browsers support only Java
and JavaScript. Research ActiveX
Ada is a computer programming language developed for the US Department of Defence which permits the development of very large computer systems and can cope with complex real-time applications. It was named after Augusta Ada King, Countess of Lovelace, daughter of LordByron, who worked with Charles Babbage. Research Ada
In computing, an adaptive bridge is a network bridge that remembers destination addresses in order to route subsequent packets more quickly. Research Adaptive Bridge
In computing, adaptive compression is a data compression technique that dynamically adjusts the algorithm being used based on the content of the data being compressed. Research Adaptive Compression
Adaptive Differential PCM (ADPCM) is a digital audio compression technique delivering 4:1 ratio compression. It depends upon the incoming data being similar from one sample to the next, resulting in fewer bits being required to represent changes between the samples. Research Adaptive Differential PCM
Adaptive Equalisation is a telecommunications term referring to the equalisation of received digital signals capable of adjustment during actual transmission. Research Adaptive Equalisation
In data networks, adaptive routing is routing algorithms capable of adjusting message routes in response to changes in traffic patterns or transmission channel failures. Research Adaptive Routing
an Adcock aerial is a radio aerial system consisting of two vertical open-spaced dipoles with screened horizontal connections. It thus responds almost exclusively to the vertically polarised component of a received wave and is used for radio direction finding. Research Adcock Aerial
In mechanics, an addendum circle is the circle which may be described around a circular spur wheel or gear wheel, touching the crests or tips of the teeth. Research Addendum Circle
An additive colour system is a colour reproduction system in which an image is displayed by mixing appropriate amounts of red, green and blue light, as for example in a cathode-ray tube. Research Additive Colour System
In computing, a computer's address space refers to the total amount of memory - both physical and virtual - that can be addressed by the computer.
In computing a program's address space is the actual memory used by the program when running. It may refer to physical memory, virtual memory or a combination of both. Research Address Space
The Addressograph was an early 20th century addressing machine by which printed matter, not necessarily limited to addresses, could be put on paper by the use of embossed metal printing plates. Different matter was printed at each stroke of the machine at speeds varying from 500 to 7,000 items each hour, according to the particular type of machine used.
The printing plates were in one piece on which the type was embossed, or were made up of three parts, consisting of the embossed metal plate, a card printed from the plate, and a metal frame into which both the plate and card were inserted, the card being in the upper portion. The printing plates were filed into steel filing drawers and formed a complete card index.
The addressograph was provided with a magazine which was loaded directly from a drawer, which was then placed in position under the machine. At each stroke of the machine a plate was fed from the magazine, inked by means of pads, and then advanced into the printing position. After printing, the plate was returned automatically to the drawer in its original order. Means were provided for taking two or more impressions from the plate before allowing it to leave the printing point, and of skipping those plates not required. Also, if required a portion of a plate only could be printed. Automatic selecting means were provided which enabled which enabled the machine to print only those plates required, omitting all the others. The impression could be obtained through a typewriterribbon when it was required to match a typewritten letter for example.
The material to be printed on was usually fed into the addressograph by hand, but some types of addressograph machines were provided with the means for automatically feeding the material to the printing position and stacking it after printing. The magazines of these machines could be loaded and the plates that had been printed removed without stopping the machine. Machines were also arranged to print onto paper from a roll which was then automatically cut to the required size. Means were also provided for printing matter such as the title of a newspaper or magazine in addition to the address on newspaper wrappers. Research Addressograph
Adenosine triphosphate is a molecule formed by the condensation of adenine, ribose and triphosphoric acid. It is a key compound in the mediation of energy in both plants and animals. Energy is stored when it is synthesised from adenosine diphosphate and phosphoric acid and released when the reaction is reversed. Research Adenosine triphosphate
Adhesion is the tendency of two bodies to stick together when put in close contact, or the mutual attraction of their surfaces; distinguished from cohesion, which denotes the mutual attraction between the particles of a homogeneous body. Adhesion may exist between two solids, between a solid and a fluid, or between two fluids. A plate of glass or of polished metal laid on the surface of water and attached to one arm of a balance will support much more than its own weight in the opposite scale from the force of adhesion between the water and the plate. From the same force arises the tendency of most liquids, when gently poured from a jar, to run down the exterior of a vessel or along any other surface they meet. Research Adhesion
Adobe Acrobat is a coding system developed by Adobe Systems for electronic publishing applications. It was launched 1993. Acrobat coding was designed to turn computers into information distributors that would allow Macintosh users to view a document in its original form, and can be generated directly from PostScript files. Research Adobe Acrobat
Adobe GoLive 4.0 is an HTMLdesign program. The program operates on the paradigm that layout is king. It gives you as much control over the presentation of your site as possible at the cost, however, of usability. GoLive goes out of its way to protect you from the standard nomenclature and concepts of typical Web-page design. For instance, you can place layout grids for all your elements, from text to graphics, and use layers and tables to make sure that the layout is maintained. The program creates the actual code automatically in the background, and while the resulting pages appear as you laid them out, they will not be very dynamic. Other programs would do well to emulate a number of exceptional features in GoLive. Features such as Java and JavaScript support, database integration, and XML code, considered extras in other programs, are fully integrated with this program and its interface. And GoLive includes a QuickTime editor so not only can you incorporate movies into your pages, you can also coordinate them with HTML-based pages
popping up on cue in separate frames. For all its nods to graphic design, GoLive gives you access to the HTML source code in its own editor, and the Outline view treats the text like object-oriented coding. This feature is helpful if you've got object-oriented training, but not if you're accustomed only to more typical HTML coding standards. The program's interface is clean, thanks to a clever, context-sensitive Inspector that keeps open only the window being worked on. A tabbed palette contains icons for most elements, and you can drag and drop them into your design. Access to some of the most basic tools, however, is unnecessarily convoluted. Adobe GoLive 4.0 creates an environment well-suited for graphic designers, but it's likely to present a significant challenge to those versed in traditional HTML coding. Used as a vertical application with other Adobe products, it makes a great deal of sense, but be prepared to buy into that family-of-products philosophy and perhaps into the Mac platform, as well. Research Adobe GoLive 4.0
Adobe Illustrator is an illustration program for the PC and Mac for creating high-quality PostScript line drawings. It includes the tools of a basic drawing program, and also provides the ability to use lines and curves to trace a bit-mapped image and run it into crispPostScript output. This can be done manually with the pen tool or automatically using the AutoTrace tool. AutoTrace automatically traces shapes from a template, which saves time. The end result is a PostScript line-art drawing that can be printed in a resolution limited only by the output device. The product should be considered for translating bitmapped graphics to PostScript drawings.
Adobe Illustrator uses Bezier curves which are composed of anchor points (ends of the curve) and direction points. Direction points determine the shape of your curve. You can reshape the curve by dragging its points. You can also add and moveanchor points and delete sections of your curve. Research Adobe Illustrator
Adobe PageMill is a commercial Windows HTML editor. It was originally developed for the Macintosh, it is also available for Windows 95 offering WYSIWYGHTML editing as well as incorporation of many of the most popular Web capabilities. Research Adobe PageMill
ADSL (Asymmetic Digital Subscriber Line) is a form of DSL communications in which a digital voice telephone line that uses the existing twisted pair coppertelephone network, is split into two frequency channels. Voice calls are transmitted at frequencies up to 20 kHz and data communications along the same cables but at frequencies between 25.875 kHz and 1.104 MHz. ADSL is able to achieve data receive transfer speeds of up to 6 megabits per second up to 12000 feet, or 1.5 megabits per second up to 18000 feet, with data transmission at around 256 kilobits per second. Most domestic ADSL lines are shared between subscribers, and this gives rise to 'contention', whereby the shared line can only provide so much data at a time, and if multiple users are all transferring data at the same time then the speed of transfer noticed by them all is significantly slower than when only one user is accessing the ADSL line, with a 50:1 ratio if all 50 users are simultaneously accessing the service then each will realise a transfer speed of 1/50th the potential. Research ADSL
Advanced Power Management is a feature used by some computer BIOSes in order to make the computer enter a low-power standby state after a given period of inactivity. Research Advanced Power Management
Advent was the prototypical computer adventure game, first implemented on the PDP-10 by Will Crowther as an attempt at computer-refereed fantasy gaming, and expanded into a puzzle-oriented game by Don Woods. Now better known as Adventure, but the TOPS-10 operating system permitted only six-letter filenames. Research Advent
Adware is a computer term for software that displays advertisements when it is running. If the hostcomputer is not connected to the internet when the program is running, no 'call home' is made. If the hostcomputer is connected to the internet, new advertisements are downloaded to the program. Unlike 'Spyware', no information is transmitted to unknown parties regarding buying habits, etc. Research Adware
An aeolipile is a hollow metallic ball which rotates about its vertical axis, with horizontal arm-like tubes projecting radially, and having their free ends bent round in a tangential direction. When the water in the globe is heated, and steam rushes out of the tubes, rotation is established. The aeolipile was invented in 120 BC. Research Aeolipile
Aeolotropy is the antithesis of isotropy. It is the state of those bodies or substances which do not exhibit the same qualities in all directions. Research Aeolotropy
Aerodynamics is a branch of physical science, which treats of the properties and motions of elastic fluids (air, gases), and of the appliances by which these are exemplified. This subject is often explained in connection with hydrodynamics. Research Aerodynamics
An Aerometer is an instrument used for ascertaining the weight or density of air and gases. Simpler aerometers measure only the relative weights of liquids. They consist of a tube of glass, terminated in a ball at its lower part, and divided into equal portions through its whole length. Another ball filled with mercury is soldered below to keep it vertical. The depth to which it sinks in various liquids is in inverse ratio of their relative specific gravities. In Fahrenheit's aerometer there is an adjustment by weights, so that the volume of the part immersed is constant, and thus the absolute specific gravity of the liquid tested is ascertained, that of water being previously fixed. Research Aerometer
The aerophore was an apparatus invented by Denayrouze to enable persons to enter a noxious inflammable atmosphere. It comprised an air-pump, lamp, and flexible tubing. It was tried at Chatham in January 1875 and was reported successful. Research Aerophore
An aerostatic press is a contrivance for extracting the colouring matter from dye-woods and for similar purposes. A liquid intended to carry with it the extract is brought into contact with the substance containing it, and a vacuum being made by an air-pump suitably applied, the pressure of the atmosphere forces the liquid through the intervening mass, carrying the colour or other soluble matter with it. Research Aerostatic Press
Aerostatics is the science of the equilibrium of the pressure of the air and other gasses, and the behaviour of objects supported in them. Research Aerostatics
An aethrioscope is an instrument for measuring radiation towards a clear sky. It consists of a metallic cup with a highly-polished interior of paraboloid shape, in the focus of which is placed one bulb of a differential thermometer, the other being outside. The inside bulb at once begins to radiate heat when exposed to a clear sky, and the extent to which this takes place is shown by the scale of the thermometer. The aethrioscope also indicates the presence of invisibleaqueousvapour in the atmosphere, radiation being less than when the air is dry.
In chemistry, affinity, is the force by which unlike kinds of matter combine so intimately that the properties of the constituents are lost, and a compound with new properties is produced. The force is not the same under all conditions, being very much modified by circumstances, especially temperature. The usual effect of increase of temperature is to diminishaffinity and ultimately to cause the separation of a compound into its constituents; and there is probably for every compound a temperature above which it could not exist but would be broken up. Where two elements combine to form a compound heat is almost always evolved, and the amount evolved serves as a measure of the affinity. In order that chemical affinity may come into play it is necessary that the substances should be in contact, and usually one of them at least is a fluid or a gas. The results produced by chemical combination are endlessly varied. Colour, taste, and smell are changed, destroyed, or created; harmless constituents produce strong poisons, strong poisons produce harmless compounds. Research Aethrioscope
Aetiology is a now obsolete term describing the science of the causes of phenomena. The term is still used in medicine to describe the science investigating the causation of disease. Research Aetiology
In terrestrial magnetism, agonic line is a name applied to the line which joins all the places on the earth's surface at which the needle of the compass points due north and south, without any declination. This line varies from time to time. Research Agonic Line
AIDX is a derogatory term for IBM's perverted version of UNIX, AIX, especially for the AIX 3.? used in the IBM RS/6000 series. A victim of the dreaded 'hybridism' disease, this attempt to combine the two main currents of the UNIXstream (BSD and USG UNIX) became a monstrosity to haunt system administrators' dreams. For example, if new accounts are created while many users are logged on, the load average jumps quickly over 20 due to a silly implementation of the user databases. Research Aidx
An air dam is a spoiler mounted at the front of a motor vehicle to reduce air flow to the underside of the vehicle and thereby improve stability. Research Air Dam
An air-brake is a mechanical brake applied by means of the pressure of compressed air; the term is also used for extendible flaps that provide a braking effect on aeroplanes. Compressed-air brakes are common on lorries and on some railway rolling stock. An engine-driven compressor charges an air tank to provide a reservoir of high-pressure air that can be applied to the brake pistons or diaphragms when needed. When this air pressure is released there is a characteristic hiss. Another form of air-brake is a parachute attached to the tail of an aircraft, which is opened on landing to slow the vehicle. Research Air-Brake
An air-engine is an engine in which air heated, and so expanded, or compressed air is used as the motive power. A great many engines of the former kind have been invented, some of which have been found to work pretty well where no great power is required. They may be said to be essentially similar in construction to the steam-engine, though of course the expansibility of air by heat is small compared with the expansion that takes place when water is converted into steam. Engines working by compressed air have been found very useful in mining, tunnelling, etc, and the compressed air may be conveyed to its destination by means of pipes. In such cases the waste air serves for ventilation and for reducing the oppressive heat. Research Air-engine
An air-pump is an apparatus by means of which air or other gas may be removed from an enclosed space; or for compressing air within an enclosed space. An ordinary suction-pump for water is on the same principle as the air-pump; indeed, before water reaches the top of the pipe the air has been pumped out by the same machinery which pumps the water. An ordinary suction-pump consists essentially of a cylinder or barrel, having a valve opening from the pipe through which water is to rise and a valve opening into the outlet pipe, and a piston fitted to work in the cylinder (the outlet valve may be in the piston).
The arrangement of parts in an air-pump is quite similar. The barrel of an air-pump fills with the air which expands from the receiver (that is, the vessel from which the air is being pumped), and consequently the quantity of air expelled at each stroke is less as the exhaustion proceeds, the air getting more and more rarefied. Suppose that the receiver (so called because it receives objects to be experimented on) is exactly as large as the barrel; by the first stroke there is just half the air removed, by the second there is one-fourth, by the third there is an eighth, and so on. Suppose the barrel is one third of the receiver as to volume. On raising the piston the air which filled the receiver now fills both barrel and receiver, so that one quarter is removed at the first stroke, one quarter of the remaining three quarters is removed at the second stroke - that is, three sixteenths, and one quarter of nine sixteenths at the third stroke, and so on.
Many interesting experiments may be made with the air-pump. If an animal is placed beneath the receiver, and the air exhausted, it dies almost immediately; a lighted candle under the exhausted receiver immediately goes out. Air is thus shown to be necessary to animal life and to combustion. A bell, suspended from a silkenthread beneath the exhausted receiver, on being struck cannot be heard. If the bell be in one receiver from which the air is not exhausted, but which is within an exhausted receiver, it still cannot be heard. Air is therefore necessary to the production and to the transmission of sound. A shrivelled apple placed beneath an exhausted receiver becomes as plump as if quite fresh, being thus shown to be full of elastic air. The air-pump was invented by Otto von Guericke, burgomaster of Magdeburg, about the year 1654. Research Air-Pump
Airsource Pro is a computer program designed for businesses that depend on their alphanumeric pagers. This product features no limitations on groups, terminals, carriers, predefined messages, pager contacts, or email options. It allows messaging up to 30,000 characters in length. Research Airsource Pro
Albumen or albumin is a substance, or rather group of substances, so named from the Latin for the white of an egg (albus) , which is one of its most abundant known forms. It may be taken as the type of the protein compounds or the nitrogenous class of food stuffs. One variety enters largely into the composition of the animal fluids and solids, is coagulable by heat at and above 160 degrees, and is composed of carbon, hydrogen, nitrogen, and oxygen, with a little sulphur. It abounds in the serum of the blood, the vitreous and crystalline humours of the eye, the fluid of dropsy, the substance called coagulable lymph, in nutritive matters, the juice of flesh, etc. The blood contains about seven percent of albumen. Another variety called vegetable albumen exists in most vegetable juices and many seeds, and has nearly the same composition and properties as egg albumen. When albumen coagulates in any fluid it readily encloses any substances that may be suspended in the fluid. Hence it is used to clarify syrupy liquors. In cookery white of eggs is employed for clarifying, but in large operations like sugar-refining the serum of blood is used. From its being coagulable by various salts, and especially by corrosive sublimate, with which it forms an insoluble compound, white of egg is a convenient antidote in cases of poisoning by that substance. With lime it forms a cement to mend broken ware.
In botany the name albumen is given to the farinaceous matter which surrounds the embryo, the term in this case having no reference to chemical composition. It constitutes the meat of the cocoa-nut, the flour or meal of cereals, the roasted part of coffee, etc. Research Albumen
The albumins are simple proteins consisting largely of glutamic and aspertic acids, leucine and isoleucine and relatively large amounts of cysteine and methionine. Albumins are readily soluble in water and crystallise well. Research Albumin
The albuminoids are organic nitrogenous compounds chemically allied to the proteins, but differing from them and from one another in various ways. The chief recognised albuminoids are collagen, gelatin, keratin, elastin, ossein and chitin. Research Albuminoids
Alchemy was the medieval forerunner to chemistry. It was the supposed technique of transmuting base metals, such as lead and mercury, into silver and gold by the philosopher's stone, a hypothetical substance, to which was also attributed the power to give eternal life. This aspect of alchemy constituted much of the chemistry of the Middle Ages. More broadly, however, alchemy was a system of philosophy that dealt both with the mystery of life and the formation of inanimate substances.
Alchemy was a complex and indefinite conglomeration of chemistry, astrology, occultism, and magic, blended with obscure and abstruse ideas derived from various religious systems and other sources. It was practised in Europe from ancient times to the Middle Ages but later fell into disrepute when chemistry and physics developed. Alchemy probably began in Egypt, where it is mentioned in very early records. Many legends developed regarding the origin of this mystical science, which is variously attributed to Hermes Trismegistus, to the fallen angels of the Book of Genesis, and yet again by revelation to Moses and Aaron. The origin through Hermes was most generally accepted, and has affected chemical language down to the present day (for example, hermetically sealed). During the 4th and 5th centuries the writings of the alchemists continued increasing until by the end of the 5th century speculative alchemy had reached its highest point in the Alexandrian schools. During the Islamic conquests, many Arabs and Persians became notable alchemists.
One of the best known alchemists was Jabir ibn Hayyan, known to western Europe as Geber. His ideas were very similar to those of the old Alexandrian philosophers, and he also believed in the influence of the planets on metals. The theory of transmutation, which can be traced quite easily in the writings of the Greek philosophers, continued to exist amongst the alchemists of the Middle Ages and men such as St Albertus Magnus, Roger Bacon, and Vincent of Beauvais all believed in it. Even well into the 17th century alchemistic ideas were still held, at least from the academic point of view, by the chemists of the period. Among them may be mentioned Johann Glauber, Robert Boyle, and, for some time Isaac Newton and Gottfried Leibniz, and even Dr Johnson, who was interested in chemistry. Research Alchemy
Alcohol, or ethyl alcohol,( CaHgO), is the intoxicating part of all liquids that have undergone vinous fermentation, may be extracted by distillation, and is a limpid colourless liquid, with an agreeable smell and a strong pungent taste. When brandy, whisky, and other spirituous liquors, themselves distilled from cruder materials, are redistilled, highly volatile alcohol is the first product to pass off. The alcohol thus obtained contains much extraneous matter, including water, from the first as much as 20 or 25 percent, and increasing greatly as the process continues. Charcoal and carbonate of soda put in the brandy or other liquor, partly retain the fusel-oil and acetic acid it contains. The product thus obtained by distillation is called rectified spirits or spirits of wine, and contains from 55 to 85 percent of alcohol, the rest being water. By distilling rectified spirits over carbonate of potassium, powdered quicklime, or chloride of calcium, the greater part of the water is retained, and nearly pure alcohol passes over. It is only, however, by repeated digestion with desiccating agents and subsequent distillation that the last traces of water can be removed.
The specific gravity of alcohol varies with its purity, decreasing as the quantity of water it contains decreases. This property is a convenient test of the alcoholic strength of liquors that contain only alcohol and water; but on account of the condensation that invariably takes place on the mixture of these two liquids, it can be applied only in connection with special tables of reference, or by means of an instrument specially adapted for the purpose (known as an alcoholometer.) By simple distillation the specific gravity of alcohol can scarcely be reduced below .825 at 60 degrees Fahrenheit; by rectification over chloride of calcium it may be reduced to .794; as it usually occurs it is about .820. Alcohol is composed of carbon, hydrogen, and oxygen, in the proportions expressed by the formula CaHgO. Under a barometric pressure of 29.5 inches it boils at 173 degrees Fahrenheit or 78.4 degrees Centigrade; in the exhausted receiver of an air-pump it boils at ordinary temperatures. The freezing of alcohol is effected only at the very low temperature of -203 degrees Fahrenheit. Its very low freezing-point renders it valuable for use in thermometers suited for very low temperatures.
Alcohol vapour is extremely inflammable, and burns with a pale-blue flame, scarcely visible in bright daylight. It occasions no carbonaceous deposit upon substances held over it, and the products of its combustion are carbon dioxide and water. The steady and uniform heat which it produces during combustion makes it a valuable material for lamps. It dissolves the vegetable acids, the volatile oils, the resins, extractive matters, and many of the soaps; the greater number of the fixed oils are taken up by it in small quantities only, but some are dissolved largely. When alcohol is submitted to distillation with certain acids a peculiar compound is formed, called ether. It is alcohol which gives all intoxicating liquors the property whence they are so called. Alcohol acts strongly on the nervous system, and though in small doses it is stimulating and exhilarating, in large doses it acts as a poison. In medicine it is often of great service.
The name alcohol is also applied in chemistry to a large group of compounds of carbon, hydrogen, and oxygen, whose chemical properties are analogous to those of common or ethylic alcohol. Research Alcohol
An alcoholometer is an instrument constructed on the principle of the hydrometer, to determine from the specific gravity of spirituous liquors the percentage of alcohol they contain, the scale marking directly the required proportion. If the liquor contain anything besides water and alcohol, previous distillation is necessary. Research Alcoholometer
In chemistry, aldehyde is the generic name given to the compounds of alcohol intermediate between the alcohols and the acids. Common aldehyde (C2H40) is derived from spirit of wine by oxidation, and is a colourless, limpid, volatile, and inflammable liquid, with a peculiar ethereal odour, which is suffocating when strong; specific gravity, 0.79. Atmospheric oxygen converts it into acetic acid. It decomposes oxide of silver, depositing a brilliant film of metallic silver; hence it is used in silvering curved glass surfaces. Research Aldehyde
Aldus Persuasion is a full-featured desktop-presentation product for the Mac that lets you create graphics presentations using slides, transparencies, speaker notes, audience handouts, and on-screen slide shows. It includes an outliner, freehand-drawing tools, and business-charting capabilities. presentations can be created from scratch, or can include charts created in a spreadsheet or any graphics imported from another package.
Aldus Persuasion includes an outliner to begin creating presentations. Once the outliner and slide masters are set, the program automatically creates your slides. The outline text and slide text are hot linked, so changes made to one are automatically reflected in the other. Speakers notes can be created from the outline. Aldus Persuasion lets you create multiple masters for slides, notes, and handouts. You define page orientation, background colour and pattern, and the graphics to be placed on the master. You can add a title, body text, charts, tables, or organisation charts to the master. More than one master can be used in a presentation. This means that a company can intersperse master text slides, master chart slides and master table slides in a single presentation. New masters can be created based on existing ones. The drawing tools are very advanced and allow editing of all characteristics of an object. Although Aldus Persuasion does not do calculations, it includes powerful chart editing capabilities and provides full control over axes, tick marks, legend placement, formatting of axes, switching of axes, and numerical formats. Persuasion lets you import worksheets from spreadsheet programs such as Microsoft Excel and generate charts using the data.
Aldus Persuasion outputs to a number of slide services as well as printers and film recorders compatible with the Apple System. The slide-show generator lets you set the delay between slides and layers on slides. You can set the show for full screen, partial screen, or continuous cycle, where the show automatically repeats, or set it to stop after it has gone through the show once. You can also set the show to either automatic advance where you can set the timing, or manual where you click the mouse to move from slide to slide. Research Aldus Persuasion
An alembic was a vessel made of copper or glass formerly used for distillation. The lower part of it, called the cucurbit, was shaped like a gourd, the top part which received the steam and condensed it was called the head and had a beak which was fitted into the neck of a receiver. By the end of the 19th century the alembic was all but obsolete, being replaced by the retort and the worm-still. Research Alembic
An aleurometer is a device used in bread making for measuring the quality of wheaten flour. The indications depended upon the expansion of the gluten contained in a given quantity of flour when freed of its starch by pulverization and repeated washings with water. Research Aleurometer
Algin (Alginic Acid) is an insoluble polymeric, polysaccharide substance resembling albumin, but not coagulated by heat. It is obtained from seaweed, chiefly the genera Fucus and Laminaria, as a precipitate after boiling with sodium carbonate and adding hydrochloric acid. It is used as a dressing for fabrics and paper and as a thickening for soups and jellies, and as an emulsifier in ice-cream and other foods. In an insoluble form it can be cut, turned, and polished, like horn or vulcanite. Research Algin
An algorithm is a set of well-defined rules for solving a problem in a finite number of steps. Algorithms are extensively used in computer science. The steps in the algorithm are translated into a series of instructions that the computer can understand. These instructions form the computer program. Research Algorithm
In computing, an alias is a Unix mechanism used in a shell in order to make it substitute a string by another before executing a command. Research Alias
In audio engineering, aliasing is a form of distortion which can occur during the conversion of analog signals into digital. If the input signal is more than one half the sampling rate, only portions of the signal will be present when the system samples the waveform. A false image of the waveform based on the components that were actually sampled, is created. A system which samples at 48 kHz can correctly process signals of up to 24 kHz. To remove signals above the Nyquist frequency, all A/D converters employ anti-aliasing filters. Research Aliasing
Alizarine is a substance contained in the madderroot, and largely used in dyeing reds of various shades, as Turkey red, etc. Formerly madderroot was largely employed as a dye-stuff, its capability of dyeing being chiefly due to the presence in it of alizarine; but the use of the root has been almost superseded by the employment of alizarine itself, prepared artificially from one of the constituents of coal-tar. It forms yellowish-red prismatic crystals, nearly insoluble in cold, but dissolved to a small extent by boiling water, and readily soluble in alcohol and ether. It possesses exceedingly strong tinctorial powers. Research Alizarine
Alkali is a term first used to designate the soluble parts of the ashes of plants, especially of sea-weed. Now the term is applied to various classes of bodies having the following properties in common: (1) solubility in water; (2) the power of neutralizing acids, and forming salts with them; (3) the property of corroding animal and vegetable substances; (4) the property of altering the tint of many colouring matters thus, they turn litmus, reddened by an acid, into blue; turmeric, brown; and syrup of violets and infusion of red cabbages, green. The alkalis may be regarded as water in which part of the hydrogen is replaced by a metallic radicle. The caustic alkalis are strong alkalis which have a powerful corrosive action on the skin, and the common ones are potassium hydroxide or causticpotash, sodium hydroxide or causticsoda, and lithic hydroxide. A solution of ammonia in water is termed ammonia hydroxide or volatile alkali. It is a much feebler alkali than the others, and when the solution is heated all the ammonia is driven off. Other alkalis are calcium hydroxide or slaked lime, a solution of which in water is known as lime water; barium hydroxide and strontium hydroxide, derived from the metals barium and strontium. Research Alkali
An alkalimeter is an instrument for ascertaining the quantity of free alkali in any impure specimen, as in the potashes of commerce. These, besides the carbonate of potash, of which they principally consist, usually contain a portion of foreign salts, as sulphate and chloride of potassium, and as the true worth of the substance, or price for which it ought to sell, depends entirely on the quantity of carbonate, it is of importance to be able to measure it accurately by some easy process. This process depends on the neutralization of the alkali by an acid of known strength, the point of neutralization being determined by the fact that neutral liquids are without action on either red or blue litmus solution. The alkalimeter is merely a graduated tube - a burette - with a stop-cock at the lower extremity, from which the standard acid is dropped into water in which a known weight of the substance is dissolved. The quantity required to produce neutralization being noted, the strength of the liquid tested is easily arrived at. A process of neutralization, exactly the same in principle, may be employed to test the strength of acids by alkalis, the one process being called alkalimetry the other acidimetry. Research Alkalimeter
Alkaloid is a term applied to a class of nitrogenous compounds having basic properties, found in living plants, usually in combination with organic acids. They are usually given names ending in ine, as morphine, quinine, aconitine, nicotine, caffeine, etc. Most alkaloids occur in plants, but some are formed by decomposition. Most natural alkaloids contain carbon, hydrogen, nitrogen, and oxygen, but a few contain no oxygen. The nitrogen they contain imparts to them basic properties - they are organicbases - and hence they all form salts with acids. They all possess a pronounced bittertaste, and the poisonous nature of many plants, e.g. hemlock, yew, deadly nightshade, etc, are due to the alkaloids they contain. Although formed originally within the plant, it has been found possible to prepare several of these alkaloids by artificial means. Research Alkaloid
Alkanet is a dyeing drug, the bark of the root of the Anchusa or Alkanna tinctoria, a plant of the order Boraginaceae, with downy and spear-shaped leaves, and clusters of small purple or reddish flowers. The plant is sometimes cultivated in Britain, but most of the alkanet of commerce was imported from the Levant or from southern France. It imparts a fine deep-red colour to all unctuous substances and was used for colouring oils, plasters, lip-salve, confections, etc and also in compositions for rubbing and giving colour to mahogany furniture, and to colour spurious port-wine. Research Alkanet
Alkarsin is an extremely poisonous liquid containing kakodyle, together with oxidation products of this substance, and formerly known as Cadet's fuming liquor, characterized by its insupportable smell and high degree of spontaneous combustibility when exposed to air. Research Alkarsin
Alkyloamides are groups of synthetic fatty acids designated as DEA, MEA, MIPA, and PEG. Used for thickening, gelling, emulsifying, emolliency, skin and hair conditioning, foam boosting, foam stabilizing, wetting, opacifying, lubricating, powder binding, skin protecting, fungicidal properties, and superfatting. They are found in shampoos, bubble baths, and liquid hand and body cleansers. They are harmful when contaminated by nitrosamines, and harmful to the environment. Research Alkyloamides
Allantoin is a crystalline solid substance discovered by Vauquelin in 1790 in the foetal fluids of many animals. It is reported to have healing, soothing and anti-irritating properties. Today it is extracted from urea, which is derived from the urine of most animals, and from herbs like comfrey or uvaursi, and is used in cosmetics. Research Allantoin
Alligation is a rule of arithmetic, chiefly found in the older books, relating to the solution of questions concerning the compounding or mixing together of different ingredients, or ingredients of different qualities or values. Thus if a quantity of sugar worth 50 pence the kilogram. and another quantity worth 70 pence are mixed, the question to be solved by alligation is, what is the value of the mixture by the kilogram? Research Alligation
Allotropy (from the Greek allos, other and tropos, habit), is a term used to express the fact that one and the same element may exist in different forms, differing widely in external physical properties. Thus, carbon occurs as the diamond, and as charcoal and plumbago, and is therefore regarded as a substance subject to allotropy. Research Allotropy
An alloy is a substance produced by melting together two or more metals, sometimes a definite chemical compound, but more generally a solid solution of some such compound in an excess of one of the components. Most metals mix together in all proportions, but others unite only in definite proportions, and form true chemical compounds. Others, again, will not alloy, and when fused together, and then allowed to solidify, form not a homogeneous mixture, but a conglomerate of distinct masses.
Alloys differ from their components in most of their physical properties. Their hardness is in general increased, their malleability and ductility impaired. The colour of an alloy may closely resemble that of one of the components, or may be entirely different from the colours of both. Its specific gravity is sometimes less than the mean of its component metals. Alloys are always more fusible than their components, at any rate than the least fusible component. Newton's fusible metal, composed of three parts of tin, two or five parts of lead, and five or eight parts of bismuth, melts at temperatures varying from 198 degrees to 210 degrees Fahrenheit (and therefore in boiling water); its components fuse respectively at the temperatures 442 degrees, 600 degrees and 478 degrees Fahrenheit. Sometimes each metal retains its own fusing-point. With few exceptions metals are not much used in a pure state. 19th century British gold coins contained eight percent silver; 19th century British silver coins 7.1 percent copper. Printer's types were made from an alloy of lead and antimony; brass and a numerous list of other alloys are formed from copper and zinc; bronze from copper and tin. Research Alloy
Alpha hydroxy acids are a group of acids that appear naturally in fruit. They are used in toners, creams, and masks to exfoliate and moisturise the skin. They can be a skin irritant causing redness and rashes. Research Alpha hydroxy acids
Alpha Particles are the nuclei of the atom of helium, comprising two neutrons and two protons, and thus exhibiting a positive electric charge. Research Alpha Particles
Alpha/three is a file manager that uses the dBase III table and index format. It was a strong choice for companies which have standardised on dBase and have a lot of users who need to work with the data but are not dBase programmers. Although Alpha/three is a good complement to dBase lIl Plus, it has many features that make it a very good stand-alone file manager including data validation, a powerful report writer and a form letter generator which can insert variable text into standard form letters. Research Alpha/three
Alphanumeric is a term meaning consisting of the letters of the alphabet, numbers, and special characters used by computers. The typewriter or computer keyboard is called an
alphanumeric keyboard since it has keys for all these letters, numbers, and characters. A computer may have an
alphanumeric display, which shows only alphanumeric characters, as opposed to a display with a full graphics capability, which can show such drawings as bar charts. Research Alphanumeric
An altazimuth is an astronomical instrument similar to a theodolite, having a telescope so mounted that it can be turned round in a plane perpendicular to the horizon, while it and the graduated vertical circle connected can also be turned horizontally to any point of the compass above a graduated horizontal circle. The altazimuth can thus determine the altitude and azimuth of objects, hence the name. Research Altazimuth
Alternating current is electric current which changes direction rhythmically, rising from zero to a maximum in the positive direction, falling to zero again and then increasing to a maximum in the negative direction before returning again to zero, after which the cycle repeats. The number of cycles per second is the frequency of the alternating phenomenon. British domestic
alternating current exhibits 50 cycles per second, where as American domestic
alternating current exhibits 60. Research Alternating Current
An aludel was a vessel of earthenware or glass formerly used for condensation by the alchemists and early chemists. The aludel was shaped like an Indian club and was used for condensing on the inside the metallic fumes produced in the process of distilling the more volatile metals out of their ores. Aludels were connected in series, typically between 500 and 600 connected to a single furnace. Research Aludel
Alum is a crystalline, astringent substance with a sweetish taste. It is a double sulphate of potassium and aluminium with water of crystallization. It crystallizes in colourless regular octahedra. Its solution reddens vegetable blues. When heated, its water of crystallization is driven off, and it becomes light and spongy with slightly corrosive properties, and is used as a caustic under the name of burnt alum.
Alum is prepared in Great Britain at Whitby from alum-slate, where it forms the cliffs for miles, and at Hurlet and Campsie, near Glasgow, from bituminous alum shale and slate-clay, obtained from old coal-pits. It is also prepared near Rome from alum stone. Common alum is strictly potash alum; other two varieties are soda alum and ammonia alum, both similar in properties. Iron alum (pale mauve) and chrome alum (deep purple) are compounds containing iron and chromium in place of aluminium.
Alum is employed to hardentallow, to remove grease from printers' cushions and blocks in calico manufactories; in dyeing as a mordant. It is also largely used in the composition of crayons, in tannery, and in medicine (as an astringent and styptic). Wood and paper are dipped in a solution of alum to render them less combustible. Research Alum
Aluminium is a bluish-silver-white, malleable, ductile, light, trivalent metallic element with good electrical and thermal conductivity, high reflectivity, and resistance to oxidation and is the most abundant metal in the earth's crust occurring always in combination. It has the symbolAl. Aluminium was discovered in 1827, but nowhere found native, although its oxide, alumina is abundantly distributed. The minerals bauxite and cryolite are sources of aluminium, but the chief source is the pure oxide, from which the metal is obtained by means of a strong electric current. It forms several useful alloys with iron and copper; one of the latter (aluminium gold) much resembles gold, and is made into cheap trinkets. Another, known as aluminium bronze, possesses great hardness and tenacity. Spoons, tea and coffee pots, dish-covers, musical and mathematical instruments, trinkets, etc, are made of aluminium, as are aircraft parts on account of its light weight. Research Aluminium
Aluminium Bronze is an alloy of copper and aluminium, the metals being combined in different proportions according to the kind of bronze wanted. One variety is of a yellow or golden colour, and is made into watch-chains and ornamental articles. Research Aluminium Bronze
Amalgam is a name applied to the alloys of mercury with the other metals. One of them is the amalgam of mercury with tin, which is used to silvermirrors. Mercury unites very readily with gold and silver at ordinary temperatures, and advantage is taken of this to separate them from their ores, the process being called amalgamation. The mercury dissolves and combines with the precious metal and separates it from the waste matters, and is itself easily driven off by heat. Research Amalgam
Ambergris is a substance derived from the intestines of the sperm-whale, and found floating or on the shore; yellowish or blackish white in colour, it is very light; melts at 140 degrees Fahrenheit, and is entirely dissipated on red-hot coals. It is soluble in ether, volatile oils, and partially in alcohol, and is chiefly composed of a peculiar fatty substance. Its odour is very agreeable, and hence it is used as a perfume. Research Ambergris
American cloth was a smooth surfaced, glazed cloth used for covering work benches in wig factories so as to prevent the hairs catching in splinters of the bench. American cloth was slowly replaced by Formica and other smooth plastic surfaces. Research American Cloth
American Wire Gauge (AWG) is descriptive of the diameter of wire conductors, particularly in twisted pair cabling; The AWG has an effect on the transmission capacity and distance a given wire can offer. Internationally, wire size is described in millimetric diameter, except in England, where the weight in pounds per mile is used. Research American Wire Gauge
Americium is a synthetic chemical element with the symbol Am that is the most frequently used element for superconducting devices. It is artificially produced from plutonium, and is used commercially in gauges, distance-sensing devices, and smoke alarms. Americium was first synthesised in a nuclear reactor in 1944 by Glenn Seaborg, Ralph James, Leon Morgan, and Albert Ghiorso. Research Americium
AmiBroker is a computer program for the PC that helps you study and predict market trends and maintain a portfolio of shares. It incorporates a powerful set of technical analysis tools, an OLE automation interface with a rich command set, and several options for importing quotation data. It has a clean and user-friendly interface. This version has a new tool for automatic download of quotes from the Internet, and new options for data import. Research AmiBroker
The amides are a group of organic compounds derived from ammonia by the replacement of a portion of the hydrogen by an acidradical. they are usually solid substances, are neutral to litmus, but act as bases to acids, with which they form salts. Treated with phosphoric anhydride, they are dehydrated, and become nitriles; while if they are boiled with aqueouscausticpotash they give off ammonia, and leave the potash in combination with the acid. Research Amides
Amidogen is the group NH2. It is known only in combination forming amides with acid radicals, and amines with alkyls. The products are generally known as amido compounds. Research Amidogen
The Commodore Amiga was an American personal computer produced in 1985 based on the Motorola M1 68000 processor running at 8 Mhz. The Commodore Amiga was fitted with 512 kb of RAM, expandable to 8.5 mb and ran the Amiga DOS operating system. The Commodore Amiga had a 16-colour screen with a resolution of 640 x 200 pixels or 80 x 25 character cells and an integral 3.5 inch floppy disk drive. Research Amiga
Amines are compounds derived from ammonia by replacing the hydrogen with one or more alkyls or alcohol radicals; they are primary, secondary or tertiary according to the number of hydrogen atoms replaced. The amines are mostly volatile, and act as bases, forming salts with acids in a similar manner to ammonia. Research Amines
Ammonia (Spirits of Hartshorn or the volatile alkali) is an alkaline colourless gas comprised of nitrogen and hydrogen. Formulae NH3. It occurs in nature in minute quantities in the atmosphere and in natural waters, being derived from the decomposition of nitrogenous organic substances. It appears to have been known to the ancients, but was obtained by Joseph Priestley in 1774 who termed it alkaline air. Its exact composition was demonstrated by Marcellin Berthelot in 1785. Ammonia is a pungent gas. Joseph Priestley obtained ammonia from sal-ammoniac by the action of lime, by which method it was still generally prepared until the 20th century. Ammonia is used for many purposes, both in medicine and scientific chemistry; not, however, in the gaseous state, but frequently in solution in water, under the names of liquid ammonia, aqueous ammonia, or spirits of hartshorn. It is evolved when animal refuse - manure - decomposes, but it is generally prepared from the ammoniacal liquor obtained as a by-product on distilling coal. Many animal substances, such as bones, clippings and shavings of horn, hoof, etc, and certain vegetable matters yield ammonia when heated. Research Ammonia
Ammonium sulphate is a brown-grey to white crystalline solid which is used primarily as a nitrogen fertilizer. It is a particularly good fertilizer for rice. It is also used as a general-purpose food additive and as an additive to supply nitrogen in fermentation processes. It is produced by the reaction of by-product ammonia from cokeovens with sulphuric acid.
Ammonium sulphate is a powerful oxidiser. When heated, the sulphate decomposes at 100 degrees C and yields ammonium bisulphate. When heated to decomposition, it emits very toxic fumes of nitrous oxide, ammonia, and sulphurtrioxide. Ammonium sulphate is insoluble in alcohol and acetone. If mixed with oxidisers, ammonium sulphate is an explosion hazard during a fire. Ammonium sulphate is also known as ammonium hydrogen sulphate, diammonium sulphate, and sulphuric acid, diammonium salt. Research Ammonium Sulphate
Amorphous is a term applied to substances devoid of characteristic shape, or of different properties in different directions, in contradistinction to crystalline bodies. Research Amorphous
Ampere's Theory is the theory that magnetism consists in the existence of electric currents circulating round the particles of magnetic bodies, being in different directions round different particles when the bodies are unmagnetized, but all in the same direction when they are magnetized. Research Ampere's Theory
Amplitude Modulation is modifying a 'carrier' signal by varying its instantaneous power to represent the information it carries. Most commonly called 'AM'. Research Amplitude Modulation
The Amstrad PC 1512 was a British personal computer produced in 1986. The
Amstrad PC 1512 introduced low-cost personal computers to the market, costing one quarter what it's competitors did at the time, roughly 400 pounds compared to the more common price tag of just under 1500 pounds. The Amstrad PC 1512 was based upon the Intel 8086 processor running at 8 Mhz and was fitted with 512 kb of RAM, expandable to 640 kb and ran MS-DOS 3.2 and the DOS+ operating systems. The Amstrad PC 1512 had a 14-inch 16-colour monitor with a resolution of 640 x 200 pixels or 80 x 25 character cells. Storage was provided by 5.25-inch 360 kb floppy disk drives and a 10 or 20 mb internal hard disk. Research Amstrad PC 1512
AMTOR is an acronym for ;amateur teleprinting over radio', a broadcast mode that uses FSK to send messages containing error detection capabilities and the ability request retransmission of missing or corrupted data. Research AMTOR
Amyl acetate is a colourless liquid with an odour similar to pears or bananas. It is used as a solvent in nail varnishes, lacquers and as an artificial flavouring (for pears) and in perfume. As early as 1892 Dr George Black in his Family Health Book strongly advised against the consumption of amyl acetate, describing the substance thus:
It is a most unwholesome and deleterious compound, and sweets flavoured with it should be avoided. Research Amyl Acetate
Amylene is a colourless, mobile liquid with an aromatic odour first procured by Balard of Paris in 1844 by distilling fusel oil with chloride of zinc. The vapour was employed instead of chloroform first by Snow in 1856, but is very dangerous and its use ceased around the start of the 20th century. Research Amylene
Analog is a freewarecomputer program for analysing http server log files. Analog works on almost any operating system and is designed to be fast and to produce accurate and attractive statistics which provide technical reports about the http server. Analog does not attempt to guess at visitor activity, but reports the facts as recorded in the http log files. This diminishes Analog's usefulness for producing management reports for marketing departments. Analog produces a single page HTMLformat report which includes graphs and sub-reports. The actual reports produced may be selected and customised through adjustment of the Analog configuration file. Research Analog More information about Analog
An analog computer represents variables by voltages, and these can be continuously variable.
Analog computers were very popular in the 1950s and 1960s, but the technology of the time was very restrictive. Valve operational amplifiers drifted in an alarming manner and transistor versions required very careful design. The arrival of integrated circuits should have revolutionised
analog computers as cheap, small and stable, but the technology also changed digital computers by increasing their speed to the point where they finally became viable. Research Analog Computer
Analog Loopback (ALB) is connecting a received analog signal to the return transmitting path; a common test method for locating transmission problems in data transmission systems. Research Analog Loopback
An analog signal is a signal in the form of a continuous varying in step with the actual transmitted information; attempts to transmit an exact replica of the inputted signal down a communications channel. Research Analog Signal
Analog Transmission is communications by transmission of continuously varying representations of the input signal, as compared to coded words in digital transmission. Research Analog Transmission
In animals and plants, anastomosis is the inosculation of vessels, or the opening of one vessel into another, as an artery into another artery, or a vein into a vein. By means of anastomosis, if the course of a fluid is arrested in one vessel it can proceed along others. It is by anastomosis that circulation is re-established in amputated limbs, and in aneurism when the vessel is tied. Research Anastomosis
The term anatomical describes something refering to anatomy. That is, in simple terms, the structure of a body or plant. Thus in psychology, anatomical refers to the physical structure of the body or a part of it, as distinct from abstract thought or perception. Research Anatomical
An android is an automaton figure (a robot) of a human being. One of the most famous androids was the chess-player made by or for the baron of Kempelen in 1784 which caused quite a stir when it was exhibited in Paris, and even played chess against Napoleon. Research Android
An anemometer is a device for measuring the strength and velocity of wind. It was invented by Wolfius in 1709. The force of the wind was usually measured by the pressure of the wind upon a square plate attached to one end of a spiral spring (with its axis horizontal), which yielded more or less according to the force of the wind, and transmitted its motion to a pencil which left a trace upon paper moved by clockwork. The hemispherical cup anemometer (still used today) was invented in 1846 by Robinson and consists of four hemispherical cups which rotate horizontally with the wind, and a combination of wheels which record the number of revolutions in a given time. Research Anemometer
An anemoscope is any contrivance indicating the direction of the wind. The term is generally applied to a vane which turns a spindle descending through the roof to a chamber, where, by means of a compass-card and index, the direction of the wind is shown. Research Anemoscope
An aneroid barometer is a barometer first invented in the mid 19th century, not containing a liquid, but constructed on a totally different principle from a mercurial barometer. Various forms of aneroid barometer have existed, the most popular form consists of a cylindrical metal box exhausted of air, with a thin corrugated metal lid. As the pressure increases, the elastic lid is forced inwards, and when the pressure decreases the lid is forced outwards. A spring connected to the inside of the lid and to multiplying levers inside the box transmits these lid movements to an index which moves on a graduated scale. The aneroid barometer is prone to become out of alignment due to knocks and wear and tear, but is very portable and as such was used for determining the heights of mountains. Research Aneroid Barometer
An angle is the point where two lines meet, or the meeting of two lines in a point. A plane rectilineal angle is formed by two straight lines which meet one another, but are not in the same straight line; it may be considered the degree of opening or divergence of the two straight lines which thus meet one another.
A right angle is an angle formed by a straight line falling on another perpendicularly, or an angle which is measured by an arc of 90 degrees.
An acute angle is that which is less than a right angle.
An obtuse angle is that which is greater than a right angle.
Acute and obtuse angles are both called oblique, in opposition to right angles. Exterior or external angles are the angles of any rectilineal figure without it, made by producing the sides. A solid angle is that which is made by more than two plane angles meeting in one point and not lying in the same plane, as the angle of a cube. A spherical angle is an angle on the surface of a sphere, contained between the arcs of two great circles which intersect each other. Research Angle
Anhydride is an oxide of an element or organicradical, capable of combining with water to form an acid. Nearly all the non-metallic elements, as well as several of the metallic elements form
anhydrides. Thus sulphuric anhydride, SO3, with water makes sulphuric acid. Research Anhydride
Aniline (Phenylamine or amido-benzene) is an oily liquid occurring in coal-tar and made by the reduction of nitro-benzene and used in the manufacture of chemicals, dyes and drugs. It was discovered in 1826 by Unverdorben among the products of distillation of indigo. In 1856 Bechamp obtained it from nitro-benzene. Benzene, when acted on by nitric acid, produces nitro-benzene; and this, when reduced with iron-filings or scraps, and a small amount of hydrochloric acid, yields aniline. It is also prepared by passing an electric current through a mixture of nitro-benzene and sulphuric acid. It is a colourless oily liquid, somewhat heavier than water, with a peculiar smell, and a burning taste. It is a basic substance, and, like the alkaloids, forms salts with different acids. An important group of aniline dyes are the azo dyes, obtained by the action of nitrous acid and the phenols on aniline. The manufacture of these aniline dyes was introduced in 1856 by Mr. Perkin of London but were most largely manufactured in Germany. Research Aniline
Animal Chemistry is the department of organicchemistry which investigates the composition of the fluids and the solids of animals, and the chemical action that takes place in animal bodies. There are four elements, sometimes distinctively named organic elements, which are invariably found in living bodies, that is carbon, hydrogen, oxygen, and nitrogen. To these may be added, as frequent constituents of the human body, sulphur, phosphorus, lime, sodium, potassium, chlorine, and iron.
The four organic elements are found in all the fluids and solids of the body. Sulphur occurs in blood and in many of the secretions. Phosphorus is also common, being found in nerves, in the teeth, and in fluids. Chlorine occurs almost universally throughout the body; lime is found in bone, in the teeth, and in the secretions; iron occurs in the blood, in urine, and in bile; and sodium, like chlorine, is of almost universal occurrence. Potassium occurs in muscles, in nerves, and in the blood-corpuscles. Minute quantities of copper, silicon, manganese, lead, and lithium are also found in the human body.
The compounds formed in the human organism are divisible into the organic and inorganic. The most frequent of the latter is water, of which two-thirds (by weight) of the body are composed. The organic compounds may, like the foods from which they are formed, be divided into the nitrogenous and non-nitrogenous. Of the former the chief are albumen (found in blood, lymph, and chyle), casein (found in milk), myosin (in muscle), gelatin (obtained from bone), and others. The non-nitrogeneous compounds are represented by organic acids, such as formic, acetic, butyric, stearic, etc by animal starches, sugars; and by fats and oils, as stearin and olein. Research Animal Chemistry
Annealing is a process to which many articles of metal and glass are subjected after making, in order to render them more tenacious, and which consists in heating them and allowing them to cool slowly. When the metals are worked by the hammer, or rolled into plates, or drawn into wire, they acquire a certain amount of brittleness, which destroys their usefulness, and has to be remedied by annealing. The tempering of steel is one kind of annealing. Annealing is particularly employed in glass-houses, and consists in putting the glass vessels, as soon as they are formed and while they are yet hot, into a furnace or oven, in which they are suffered to cool gradually. The toughness is greatly increased by cooling the articles in oil. Research Annealing
In astronomy, an anomaly is the angle which a line drawn from a planet to the sun has passed through since the planet was last at its perihelion or nearest distance to the sun. The anomalistic year is the interval between two successive times at which the earth is in perihelion, or 365 days 6 hours 13 minutes 45 seconds. In consequence of the advance of the earth's perihelion among the stars in the same direction as the earth's motion and of the precession of the equinoxes, which carries the equinoxes back in the opposite direction to the earth's motion, the anomalistic year is longer than the sidereal year, and still longer than the tropical or common year. Research Anomaly
The anorthoscope is an optical apparatus described by Carpenter in 1868. In it distorted figures lose their distortion when in rapid motion. Research Anorthoscope
Answer Back is an electrical and/or visual indication to the call originating end that the call terminating end is on the line. First associated with the International Telex network, answerbacks are also recommended in CCITT-standard fax machines and are provided in most PC data communications software packages. Research Answer Back
Anthracene is a complex hydrocarbon contained in coal-tar, and obtained from the highest-boiling portion of the tar,
namely the so-called 'green grease', which forms the last portion of the heavy oil or dead oil resulting in the fractional distillation of the tar. Anthracene is a commercial product of some importance, as a source of alizarine and numerous other dyes of a similar kind. The commercial product forms a hard crystalline cake containing some 50 percent of anthracene; when pure it crystallizes in the form of glistening, white plates showing a bluish-violet fluorescence, and has neither taste nor smell. Several colours used in dyeing are known as 'anthracene colours'. Research Anthracene
Anthraquinone is a yellow, crystalline solid obtained by oxidising anthracene with chromic acid mixture. It is used in the manufacture of alizarin and its derivatives. Research Anthraquinone
Anthropology is the study of humanity, divided into two main areas of interest: the physical structure and evolution of mankind, and the social organizations and cultural systems of human groups. In the 19th century, anthropology was concerned with theories of both physical and social evolution, so-called 'primitive' people being regarded as representative of earlier stages of mankind. Both physical and social differences were considered together in theories of race. In the early 20th century, the study of social and cultural differences became a separate discipline, known as social anthropology in the UK and cultural anthropology in the USA. At the same time, anthropologists started to become more involved in fieldwork research. Early anthropologists like Frazer had had little or no experience of the different societies they were writing about, but Malinowski was one of the first anthropologists to observe a society by living with the people, studying their language as well as their cultural system, and writing about them in an ethnography, an analysis based on such fieldwork.
In the USA, cultural anthropology traces its origins to Franz Boas, who studied various North-west Indian groups, and whose many notable students included Mead. Until the Second World War, most anthropological studies were of 'primitive' people, usually in European colonies, and the dominant theoretical influence in the UK was functionalism. After the Second World War, more studies began to be carried out in societies with long traditions of written history in Europe and Asia, and new theoretical approaches, such as the structuralism of Levi-Strauss, appeared. Modern anthropologists study people in all settings, from industrial cities to remote rain forests. By living within a society and participating in its activities, learning its language, and observing its daily life, the anthropologist builds up a knowledge of that society' s kinship system, social organization, culture, law, rituals, and myths. By comparing this cultural system with others, the anthropologist attempts to understand the variety of human social experience as much as possible through the eyes of different people all over the world. Research Anthropology
Anthropometry is the systematic examination of the height, weight, and other physical characteristics of the human body. The science was started in the late 19th century, and it was shown in the British Association Report of 1883 that variations in stature, weight, and complexion, existing in different districts of the British islands, are chiefly due to difference of racial origin.
The Scotch male adults stand first in height (68.71 inches), the Irish second (67.90 inches), the English third (67-66 inches), and the Welsh last (66.66 inches). In weight the Scotch take the first place (165.3 lbs.), the Welsh the second (158.3 lbs.), the English the third (155.0 lbs.), and the Irish the last (154.1 lbs.).
The average height of adult females is 4.71 inches less than the male average, and their average weight 32.2 lbs. under that of the males. At the same time, a report was published giving the average height of the adult males of the principal races or nationalities of the world as: Polynesians 69.33 in., Patagonians 69 in., Negroes of the Congo 69 in., Scotch 68.71 in., Iroquois Indians 68.28 in., Irish 67.90 in., United States (whites) 67.67 in., English 67.66 in., Norwegians 67.66 in., Zulus 67.19 in., Welsh 66.66 in., Danes 66.65 in., Dutch 66.62 in., American Negroes 66.62 in., Hungarians 66.58 in., Germans 66.54 in., Swiss 66.43 in., Belgians, 66.38 in., French 66.23 in., Berbers 66.10 in., Arabs 66.08 in., Russians 66 .04 in., Italians 66 in., Spaniards 65.66 in., Innuit 65.10 in., Papuans 64.78 in., Hindus 64.76 in., Chinese 64.17 in., Poles 63.87 in., Finns 63.60 in., Japanese 63.11 in., Peruvians 63 in., Malays 62.34 in., Lapps 59.2 in., Bosjesmans 52.78 in. The general average being 65.25 in.
The report did acknowledge that more numerous measurements might alter some of the figures considerably. Research Anthropometry
Antichlor is the name given to any chemical substance, such as sodium hyposulphite, employed to remove the small quantity of chlorine which obstinately adheres to the fibres of the cloth when goods are bleached by means of chlorine. Research Antichlor
An anticyclone is a phenomenon presenting some features opposite to those of a cyclone. It consists of a region of high barometric pressure, the pressure being greatest in the centre, with light winds flowing outwards from the centre, and not inwards as in the cyclone, accompanied with great cold in winter and with great heat in summer. Research Anticyclone
Antifriction metal is a name given to various alloys of tin, zinc, copper, antimony, lead, etc, which oppose little resistance to motion, with great resistance to the effects of friction, so far as concerns the wearing away of the surfaces of contact. Babbitt metal consisting of 50 parts tin, 5 parts of antimony and 1 part copper is one of them. Research Antifriction Metal
Antimony white is a pigment formed from antimonyoxide. The pigment is produced by roasting the black antimony in the presence of air, the fumes being condensed to form an amorphous white pigment. Antimony white is fine textured and very opaque, but tends to discolour in the presence of sulphur and retards the drying of linseed oil. Research Antimony White
Antioxidants are substances that slow the breakdown of nutrients and counteract the destructive effect of free radicals (chemically reactive compounds) in the body. There are several types which include vitamins A, E, C complex, and B complex, the minerals selenium and zinc, and the synthetic compounds BHT and BHA. Vitamins A, C, and E as well as BHA, and BHT are used as preserving agents in cosmetics. Research Antioxidants
An antitoxin is a substance having the effect of counteracting poison in the animal system, especially of counteracting toxins, or poisonous matters present in the system in some serious disease. During the 19th century it was discovered that by introducing a toxin in gradually increasing doses into the blood of an animal susceptible to it, a blood serum may be obtained, which, when introduced into the blood of another animal, has a protective effect against such a toxin. Hence arose the treatment known as sero-therapy, which has been especially successful in diphtheria. The antitoxic serum employed in this disease is obtained from the blood of horses inoculated with the bacilli of diphtheria, in gradually increasing doses, and it is introduced into the human subject by way of inoculation. Several other diseases - erysipelas and tetanus, for instance - are treated in the same way; as are certain diseases of domestic animals. Research Antitoxin
Antwerp blue is an artists' pigment consisting of zinc ferrocyanide. Antwerp Blue is similar to Prussian blue, but paler and with a more greenish tint. Research Antwerp Blue
In optics, aplanatic is a term specifically applied to reflectors, lenses, and combinations of them, capable of transmitting light without spherical aberration. An aplanatic lens is a lens constructed of different media to correct the effects of the unequal refrangibility of the different rays. Research Aplanatic
Apogee is an astronomical term referring to the position in the orbit of the Moon which is farthest from the Earth. Opposite to Perigee. Research Apogee
An Apollo asteroid is a member of a group of asteroids whose orbits cross that of the Earth. They are named after the first of their kind, Apollo, which was discovered in 1932 and then lost until 1973. Apollo asteroids are so small and faint that they are difficult to see except when close to Earth. Apollo asteroids can collide with the Earth from time to time. In Jan 1991 the Apollo asteroid 1991 BA passed 170,000 km from the Earth, the closest observed approach of any asteroid. A collision with an Apollo asteroid 65 million years ago is thought to be one of the possible causes of the dinosaurs dying out. A closely related group, the Amor asteroids, come close to Earth but do not cross its orbit. Research Apollo Asteroid
Among mathematicians and astronomers, the term apparent is applied to things as they appear to the eye, in distinction from what they really are. Thus they speak of apparent motion, magnitude, distance, height, etc. The apparent magnitude of a heavenly body is the angle subtended at the spectator's eye by the diameter of that body, and this, of course, depends on the distance as well as the real magnitude of the body; apparent motion is the motion a body seems to have in consequence of our own motion, as the motion of the sun from east to west, etc. Research Apparent
The replacement for Draw Applause, Applause II by Ashton Tate is a business graphics, charting, drawing, and presentation package all in one. It can be used to create slides, do on screen presentations, or create annotated charts. The picture Window includes drawing tools such as text, lines, circles, arcs, boxes, and polygons which can be used to annotate charts or create freehand illustrations. Images can be copied, moved deleted, rotated, sized, and stretched. Objects can be customised with fill colours, patterns, and line widths.
A small clip-art library of images is also available. The images are object-oriented so you can edit the individual elements. The program includes some interesting and artistic special effects. For example, you can create colour blends by picking two colours and the starting points for each in an enclosed area. The product automatically fills the colours so they blend into the centre of the object you are filling. This creates the illusion of three-dimensional objects. You can create slide shows with Applause II although there is no runtime slide show utility. Links can be established between Applause II and any data file, including Lotus 1-2-3, dBase, any Master product, or Framework. This means that presentations can be created more easily and efficiently than if you needed to key data in from scratch. Research Applause II
In astronomy, an apsis is one of the two points of the orbit of a heavenly body situated at the extremities of the major axis of the ellipse formed by the orbit, one of the points being that at which the body is at its greatest and the other that at which it is at its least distance from its primary. In regard to the earth and the other planets, these two points correspond to the aphelion and perihelion; and in regard to the moon they correspond to the apogee and perigee. The line of the apsides has a slow forward angular motion in the plane of the planet's orbit, being retrograde only in Venus. This in the earth's orbit produces the anomalistic year. Research Apsis
Aqua Tofana was a poisonous liquid, invented by Teofania di Adamo. After her death in 1633 her daughter, Giulia Tofana, sold the liquid at Rome and Naples in vials under the title 'Manna of St Nicholas of Bari'. It was a clear, colourless, tasteless liquid of which only a very small quantity was sufficient to produce death under symptoms which did not readily arouse suspicion of poisoning. Research Aqua Tofana
Aquatint is a method of print-making which was popular in the 18th century. Prints are produced imitating the broad effects of India ink and sepia drawings. Areas, not lines, are bitten in by dilute acid on a copper plate covered with black resin on which the design has already been traced. The process was designed by Abbe St Non in the 18th century and perfected by Jean Baptiste le Prince also in the 18th century. By the end of the 19th century
aquatint was virtually obsolete except for the tints in some coloured pictures. Research Aquatint
In mechanics the term arbor is applied to an axle or spindle of a wheel or opinion. The term is also applied to a mandrel used in lathe turning. Research Arbor
An arc lamp or arc light is a form of early electric lamp in which the source of light is due to a luminous arc produced in a gap between two carbon points by an electric current. Arc lamps were the first electric lamps used in Europe, but were quickly replaced at the end of the 19th century after the invention of the incandescent lamp. Research Arc Lamp
The arc wars were computer 'wars' over which archiving program one should use. The first arc war was sparked when System Enhancement Associates (SEA) sued PKWare for copyright and trademark infringement on its ARC program. PKWare's PKARC outperformed ARC on both compression and speed while largely retaining compatibility (it introduced a new compression type that could be disabled for backward-compatibility). PKWare settled out of court to avoid enormous legal costs (both SEA and PKWare are small companies); as part of the settlement, the name of PKARC was changed to PKPAK. The public backlash against SEA for bringing suit helped to hasten the demise of ARC as a standard when PKWare and others introduced new, incompatible archivers with better compression algorithms. Research Arc Wars
Archie (derived from 'archive') is a now defunct computer program which was formerly used for locating programs within ftp sites on the internet. Using Archie a user would access an Archie database, which was an index of the programs available on many ftp servers. Research Archie
Archimedes carried out experiments on the up thrust of liquids, and these experiments led to the formulation of Archimedes' Principle which states: When a body is wholly or partially immersed in a fluid it experiences an up thrust equal to the weight of the fluid displaced. This principle applies to both liquids and to gases. Research Archimedes' Principle
Archimedes' screw (Archimedean Screw) was a machine consisting of a spiral pipe or tube wound around a long cylinder. The machine, which was originally designed for raising water from the Nile, was slanted so that one end of the spiral tube was beneath the water of the river, and the other rested on the bank. The machine worked on Archimedes' Principle, and the inside of the tube really consisted of an inclined plane, down which the water flowed, though to a superficial observer it seemed to flow up in contravention of the laws of gravity. It is no longer used as it was prone to become clogged with mud, stones, weeds &c. and these are difficult to remove from a spiral tube. Research Archimedes' Screw
ArcItUp by BroadGun Software is a computer document management system providing fast, easy archival and retrieval of documents over networks, intranets and the internet. ArcItUp provides a simple to use interface. Simply print or email a document to archive it. As ArcItUp is web-based you simply search for or view a document via an Internet Browser. Because you can print to an archive you don't need to worry about the format or source of your document - if you can print it then you can archive it. Features include keyword and full-text indexing; document query, retrieval and viewing; customisable access control; batch submission; and support for Secure Sockets Layer (SSL) protocols for document security. Research ArcItUp
Area Code is colloquial term for a three or more digit number identifying one geographic area of a country providing for Direct Distance Dialling on the public telephone network system of that country. This entire system of numbers is under the umbrella of Country Code 01 in the World Numbering Plan of the CCITT. Research Area Code
The argand lamp, so named after its Swiss inventor Aime Argand, is a type of lamp in which the wick is made hollow so as to admit air to both surfaces of the flame with the effect of much increasing the light and heat generated. The
Argand lamp was invented around 1782. Research Argand Lamp
Argon is a colourless, odourless, gaseous element found in the air and volcanic gases, and is used especially as a filler for electric bulbs and electron tubes. It has the symbolAr.
Argon was found to exist in the atmosphere in small quantity (about one percent of the whole), its discovery being due to LordRayleigh and Professor Ramsay in 1894. Its discovery was led up to by the fact that the density of nitrogen as derived from the atmosphere differs from its density as derived from other sources, and this difference was found to be due to the presence of argon, which is about half as heavy again as nitrogen. The new substance was named argon by its discoverers on account of its chemical inertness (from Greek a, not, ergon work), that is, its refusal to form compounds by combining with other substances. Ramsay since showed that this 'argon' consists of a mixture of five hitherto unknown gaseous elements termed helium, neon, argon, krypton, and xenon - now called the noble gases. The amounts are extremely small; thus by volume 0.937 of argon per 100, 1 or 2 of neon per 1000,1 or 2 of helium per 1,000,000; similarly for krypton and xenon, 1 per 20 million. At the time of their discovery they were considered to be of no general importance. Research Argon
The Argonne National Laboratory is an American centre for research in nuclear and high-energy physics, located at Argonne, Illinois., near Chicago. It was founded in 1946 and is operated by the University of Chicago and Argonne Universities Association for the US Department of Energy. The staff of about 5000 conduct research into the peaceful uses of nuclear energy and related environmental problems. The first experimental boiling water reactor was constructed here in 1956. Current facilities include breeder reactors and an intense pulsed neutron source. Its protonaccelerator, called the zero-gradient synchrotron, or ZGS, was shut down in 1970. Research Argonne National Laboratory
ArGoSoft Mail Server is a fully functional SMTP/POP3/Finger email server for the Windows operating system. It' s very compact, takes only about 1 Mb of disk space, does not have any specific memory requirements, and is very easy to use. Research ArGoSoft Mail Server
Arithmetic (from the Greek arithmost, number) is primarily the science of numbers. As opposed to algebra it is the practical part of the science. Although the processes of arithmetical operations are often highly complicated, they all resolve themselves into the repetition of four primary operations, addition, subtraction, multiplication, and division. Of these the two latter are only complex forms of the two former, and subtraction again is merely a reversal of the process of addition. Little or nothing is known as to the origin and invention of arithmetic. Some elementary conception of it is in all probability coeval with the first dawn of human intelligence. In consequence of their rude methods of numeration, the science made but small advance among the ancient Egyptians, Greeks, and Romans, and it was not until the introduction of the decimal scale of notation and the Arabic, or rather Indian, numerals into Europe that any great progress can be traced. In this scale of notation every number is expressed by means of the ten digits, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, by giving each digit a local as well as its proper or natural value. The value of every digit increases in a tenfold proportion from the right towards the left; the distance of any figure from the right indicating the power of 10, and the digit itself the number of those powers intended to be expressed: thus 3464=3000+400 +60 +4.
The earliest arithmetical signs appear to have been hieroglyphical, but the Egyptian hieroglyphics were too diffuse to be of any arithmetical value. The units were successive strokes to the number required, the ten an open circle, the hundred a curled palm-leaf, the thousand a lotusflower, ten thousand a bent finger. The letters of the alphabet afforded a convenient mode of representing figures, and were used accordingly by the Chaldeans, Hebrews, and Greeks. The first nine letters of the Hebrewalphabet represented the units, the second nine tens, the remaining four together with five repeated with additional marks, hundreds; the same succession of letters with added points was repeated for thousands, tens of thousands, and hundreds of thousands.
The Greeks followed the same system up to tens of thousands. They wrote the different classes of numbers in succession as we do, and they transferred operations performed on units to numbers in higher places; but the use of different signs for the different ranks clearly shows a want of full perception of the value of place as such. They adopted the letter M as a sign for 10,000 and by combining this mark with their other numerals they could note numbers as high as 100,000,000. The Roman numerals which are still used in marking dates or numbering chapters were almost useless for purposes of computation. From one to four were represented by vertical strokes I, II, III, IIII, five by V, ten by X, fifty by L, one hundred by [, afterwards C, five hundred by D, a thousand by M. These signs were derived from each other according to particular rules, thus V was the half of X, A being also used; L was likewise the half of [. M was artistically written M and cIo, and Io, afterwards D, became five hundred, ccI represented 5000, ccIoo 10,000 Iooo 50,000, cocIooo 100,000. They were also compounded by addition and subtraction, thus IV stood for four, VI for six, XXX for thirty, XL for forty, LX for sixty.
Arithmetic is divided into abstract and practical; the former comprehends notation, numeration, addition, subtraction, multiplication, division, measures and multiples, fractions, powers and roots; the latter treats of the combinations and practical applications of these and the so-called rules, such as reduction, compound addition, subtraction, multiplication, and division, proportion, interest, profit and loss, etc. Another division is integral and fractional arithmetic, the former treating of integers, or whole numbers, and the latter of fractions. Decimal fractions were invented in the sixteenth century, and logarithms, embodying the last great advance in the science, in the seventeenth century. Research Arithmetic
Armature is a term applied to the piece of soft iron which is placed across the poles of permanent or electro-magnets for the purpose of receiving and concentrating the attractive force. In the case of permanent magnets it is also important for preserving their magnetism when not in use, and hence it is sometimes termed the keeper. It produces this effect in virtue of the well-known law of induction, by which the armature, when placed near or across the poles of the magnet, is itself converted into a temporary magnet with reversed poles, and these, reacting upon the permanent magnet, keep its particles in a state of constant magnetic tension, or, in other words, in that constrained position which is supposed to constitute magnetism. A horse-shoemagnet should therefore never be laid aside without its armature; and in the case of straight bar-magnets two should be placed parallel to each other, with their poles reversed, and a keeper or armature across them at both ends. The term is also applied to the core and coil of the electro-magnet, which revolves before the poles of the permanent magnet in the magneto-electric machine. Research Armature
The Armillary Sphere is an ancient astronomical instrument consisting of an arrangement of rings, all circles of one sphere, intended to represent the principal circles of the celestial globe, the rings standing for the meridian of the station, the ecliptic, the tropics, the arctic and antarctic circles, etc, in their relative positions. Its main use is to give a representation of the apparent motions of the solar system. The instrument was probably invented about 255 BC by the Greek astronomer Eratosthenes. Armillary spheres were used until the 17th century. Research Armillary Sphere
Arq is telegraphic code signal for 'Automatic Repeat Request,' a time-honoured method of telegraphic error correction upon which most data transmission error correction is based.
ARQ receivers check for errors and initiate an order to retransmit data blocks determined to be corrupted in transmission. Research Arq
Arsine, or arsenichydride, AsH3, is a colourless, highly poisonous gas with an unpleasant odour, and is a very powerful reducing agent. It burns in air with a clear blue flame, giving water vapour and a black deposit of arsenic. It is prepared by the action of dilute sulphuric acid on sodium or zinc arsenides. Research Arsine
Assay is a chemical test to determine the purity of a sample of metal or to determine the content of an alloy. In Britain assays are carried out by Official Assay Offices, the marks of which appear in the hallmarks of silver and gold articles. Research Asay
ASCII is the American Standard Code for Information Interchange. The most common code used for asynchronous data transmission by minicomputers and personal computers. Derived from the TWX code of the Bell Model 28 teleprinter, expanded to use all possible character combinations. ASCII consists of 7 information bits with an 8th paritybit for error checking; numerous variations exist, for example use of the 8th bit in personal computers to extend the code with a number of graphics, special language characters and diacritical marks. Many common carrier data services cannot transmit the 8th bit needed to use that common PCextension of ASCII' s alphabet. Research ASCII
Ash or ashes are the incombustible residue of organic bodies (animal or vegetable) remaining after combustion; in common usage, the term is applied to any incombustible residue of bodies used as fuel; as a commercial term, the word generally means the ashes of vegetable substances, from which are extracted the alkaline matters called potash, pearl-ash, kelp, barilla, etc. Research Ash
ASHE is a tool to help analyse binary data files under the Windows operating system. ASHE (A Scripted Hex Editor) is an easy-to-use file manipulation utility. It allows the user to locate and modify data in a file, quickly and easily. Once the structure of a file has been identified, routine changes to the file can be scripted using the integrated scripting engine. Features include an easy-to-use graphical interface, and easy-to-understand display that allows for simplified searching, and the ability to edit data in your files. It has a powerful scripting engine, and the script files can be shared with other ASHE users. Research ASHE
An aspirator is an instrument used to promote the flow of a gas from one vessel into another by means of a liquid. The simplest form of aspirator is a cylindrical vessel containing water, with a pipe at the upper end which communicates with the vessel containing the gas, and a pipe at the lower end also, with a stop-cock and with its extremity bent up. By allowing a portion of the water to run off by the pipe at the lower part of the aspirator a measured quantity of air or other gas is sucked into the upper part. Research Aspirator
ASR is telegraphic name for an 'Automatic Send/Receive' terminal station, typically one that has storage for outbound messages and holds them until called upon by the communications network to send. Research ASR
Assay is the testing of an alloy or an ore to determine the proportion of a given metal. An assay officer is someone who certifies the fineness of gold, silver and platinum. Research Assay
An astatic needle is a magnetic needle having another needle of the same intensity fixed parallel to it, the poles being reversed, so that the needles neutralize one another, and are unaffected by the earth's magnetism. Astatic needles are used in the astatic galvanometer. Research Astatic Needle
An astrolabe is an instrument used to make astronomical measurements, the term is now especially applied to an instrument used for measuring the altitudes of the stars. The Astrolabe was superseded by the quadrant and sextant. The name was also formerly given to an armillary sphere. Research Astrolabe
Astrology is the science of the relationship between events and the stars. The name was formerly used as equivalent to astronomy, but is now restricted in meaning to the belief that men can judge the effects and influences of the heavenly bodies on human and other mundane affairs, and to foretell future events by their situations and conjunctions. As usually practised the whole heavens, visible and invisible, was divided by great circles into twelve equal parts, called houses. As the circles were supposed to remain immovable every heavenly body passed through each of the twelve houses every twenty-four hours. The portion of the zodiac contained in each house was the part to which chief attention was paid, and the position of any planet was settled by its distance from the boundary circle of the house, measured on the ecliptic. The houses had different names and different powers, the first being called the house of life, the second the house of riches, the third of brethren, the sixth of marriage, the eighth of death, and so on.
The part of the heavens about to rise was called the ascendant, the planet within the house of the ascendant being lord of the ascendant. The different aspects of the planets were of great importance. To cast a persons nativity (or draw his horoscope) was to find the position of the heavens at the instant of his birth, which being done the astrologer, who knew the various powers and influences possessed by the sun, the moon, and the planets, could predict what the course and termination of that person's life would be. The temperament of the individual was ascribed to the planet under which he was born, as saturnine from Saturn, jovial from Jupiter, mercurial from Mercury, etc, words which are now used with little thought of their original meaning. The virtues of herbs, gems, and medicines were supposed to be due to their ruling planets. Astrology continues to be practised in the 21st century, despite the lack of evidence for its plausibility. Research Astrology
Astronomy is that science which investigates the motions, distances, magnitudes, and various phenomena of the heavenly bodies. That part of the science which gives a description of the motions, figures, periods of revolution, and other phenomena of the heavenly bodies is called descriptive astronomy; that part which teaches how to observe the motions, figures, periodical revolutions, distances, etc, of the heavenly bodies, and how to use the necessary instruments, is called practical astronomy; and that part which explains the causes of their motions, and demonstrates the laws by which those causes operate, is termed physical astronomy. In the 19th century new fields of investigation developed. The first of these - celestial photography - furnished us with invaluable light-pictures of the sun, moon, and other bodies, and recorded the existence of myriads of stars invisible even by the then best telescopes; while the second, spectrumanalysis, revealed a knowledge of the physical constituents of the universe, revealing for the first time for instance that in the sun there exist many of the elements familiar to us on the earth. It has also been applied to the determination of the velocity with which stars are approaching to, or receding from, our system; and to the measurement of movements taking place within the solar atmospheric envelopes. From analysis of some of the unresolved nebulae the inference was drawn that they are not star-swarms but simply cosmical vapour; whence a second inference results favourable to the hypothesis of the gradual condensation of nebulae, and the successive evolutions of suns and systems.
The most remote period to which we can go back in tracing the history of astronomy refers us to a time about 2500 BC, when the Chinese are said to have recorded the simultaneous conjunction of Saturn, Jupiter, Mars, and Mercury with the moon. This remarkable phenomenon is found, by calculating backward, to have taken place 2460 BC Astronomy has also an undoubtedly high antiquity in India. The mean annual motion of Jupiter and Saturn was observed so early as 3062 years BC; tables of the sun, moon, and planets were formed, and eclipses calculated. In the time of Alexander the Great, the Chaldeans or Babylonians had carried on astronomical observations for 1900 years. They regarded comets as bodies travelling in extended orbits, and predicted their return; and there is reason to believe that they were acquainted with the true system of the universe. The priests of Egypt gave astronomy a religious character; but their knowledge of the science is testified to only by their ancient zodiacs and the position of their pyramids with relation to the cardinal points.
It was among the Greeks that astronomy took a more scientific form. Thales of Miletus (born in 639 BC) predicted a solar eclipse, and his successors held opinions which are in many respects wonderfully in accordance with modern ideas. Pythagoras (about 500 BC) promulgated the theory that the sun is the centre of the planetary system. Great progress was made in astronomy under the Ptolemies, and we find Timochares and Aristyllus employed about 300 BC in making useful planetary observations. But Aristarchus of Samos (born in 267 BC) is said, on the authority of Archimedes, to have far surpassed them, by teaching the double motion of the earth around its axis and around the sun. A hundred years later Hipparchus determined more exactly the length of the solar year, the eccentricity of the ecliptic, the precession of the equinoxes, and even undertook a catalogue of the stars. It was in the second century after Christ that Claudius Ptolemy, a famous mathematician of Pelusium in Egypt, propounded the system that bears his name, viz that the earth was the centre of the universe, and that the sun, moon, and planets revolved around it in the following order: nearest to the earth was the sphere of the moon; then followed the spheres of Mercury, Venus, the Sun, Mars, Jupiter, and Saturn; then came the sphere of the fixed stars; these were succeeded by two crystalline spheres and an outer sphere named the primum mobile or first motion, which last was again circumscribed by the coelum empyreum, of a cubic shape, wherein happy souls found their abode.
The Arabs began to make scientific astronomical observations about the middle of the eighth century, and for 400 years they prosecuted the science with assiduity. Ibn-Yunis (around 1000 AD) made important observations of the disturbances and eccentricities of Jupiter and Saturn. In the sixteenth century Nicholas Copernicus, born in 1473, introduced the system that bears his name, and which gives to the sun the central place in the solar system, and shows all the other bodies, the earth included, revolving around him. This arrangement of the universe came at length to be generally received on account of the simplicity it substituted for the complexities and contradictions of the theory of Ptolemy. The observations and calculations of Tycho Brahe, a Danish astronomer, born in 1546, continued over many years, were of the highest value, and claim for him the title of regenerator of practical astronomy. His assistant and pupil, Johann Kepler, born in 1571, was enabled, principally by the aid he received from his master's labours, to arrive at those laws which have made his name famous: 1. That the planets move, not in circular, but in elliptical orbits, of which the sun occupies a focus. 2. That the radiusvector, or imaginary straight line joining the sun and any planet, moves over equal spaces in equal times. 3. That the squares of the times of the revolutions of the planets are as the cubes of their mean distances from the sun, Galileo, who died in 1642, advanced the science by his observations and by the new revelations he made through his telescopes, which established the truth of the Copernican theory.
Isaac Newton, born in 1642, carried physical astronomy suddenly to comparative perfection. Accepting Kepler's laws as a statement of the facts of planetary motion he deduced from them his theory of gravitation. The science was enriched towards the close of the eighteenth century by the discovery by Herschel of the planetUranus and its satellites, the resolution of the Milky Way into myriads of stars, and the unravelling of the mystery of nebulae and of double and triple stars. The splended analytical researches of Lalande, Lagrange, Delambre, and Laplace, mark the same period. The nineteenth century opened with the discovery of the first four minor planets; and the existence of another planet (Neptune) more distant from the sun than Uranus, was, in 1845, simultaneously and independently predicted by Leverrier and Adams. Of later years the sun attracted a number of observers, the spectroscope and photography having been especially fruitful in this field of investigation. From transit observations carried out at the end of the 19th century the former calculated distance of the sun has been corrected, and is now given as 92,560,000 miles. The two satellites of Mars, and of others belonging to Jupiter were also discovered towards the end of the 19th century.
The objects with which astronomy has chiefly to deal are the earth, the sun, the moon, the planets, the fixed stars, comets, nebulae, and meteors. The stellar universe is composed of an unknown host of stars, many millions in number, the most noticeable of which have been formed into groups called constellations. The nebulae are cloud-like patches of light scattered all over the heavens. Some of them have been resolved into star-clusters, but many of them are but masses of incandescent gas. Of the so-called fixed stars, many are now known to be by no means fixed, but revolve in company with another or others. Variable stars and non-luminous stars are also known. The fixed stars preserve, at least to unaided vision, an unalterable relation to each other, because of their vast distance from the earth. Their apparent movement from east to west is the result of the earth's revolution on its axis in twenty-four hours from west to east. The planets have not only an apparent, but also a real and proper motion, since, like our earth, they revolve around the sun in their several orbits and periods.
The mid-20th century saw great leaps in astronomical research with rockets, derived from the German terror weapons of the Second World War, being used to send probes and men into space for closer examination of the heavenly bodies. A retroreflector left on the Moon's surface by Apollo astronauts during the NASAApollo missions returns a high-power laser beam emitted from the Earth, enabling researchers to carry out regular monitoring and measure the distance between the Earth and the Moon to an accuracy of a few centimetres.
We now know something of the planets in our solar system. We know that Mercury is too hot to retain an atmosphere, and that Venus' brilliant white appearance is the result of its being completely enveloped by thick clouds of carbon dioxide. Below the upper clouds Venus has a hostileatmosphere containing clouds of sulphuric acid droplets. The cloud cover shields the planet's surface from direct sunlight, but the energy that does filter through warms the surface, the heat being trapped by the dense clouds, resulting in a very high surface temperature of almost 480 degrees Centigrade. Radar can penetrate the thick Venusian clouds which obscure the surface from telescopes, and has been used to map the planet's surface. Yet, despite advances, the origins of the universe, the stars planets, and the planets' asteroids remains a matter of conjecture, theory and debate. Research Astronomy
In telecommunications, asymmetrical means providing differing bandwidth in different directions. 56 K modems are asymmetrical: they offer a maximum speed of 56K for downloading, but only 28.8K or 33. 6K for uploading. Research Asymmetrical
In geometry, an asymptote is a line which is continually approaching a curve, but never meets it, however far either of them may be prolonged. This may be conceived as a tangent to a curve at an infinite distance. Research Asymptote
Asynchronous refers to occurring without central control or in an unpredictable time interval between successive elements; the typical mode of telegraphy, minicomputers and personal computers; requires s transmission of 'start' and 'stop' bits to provide decoding synchronisation at the receiver. Research Asynchronous
The idea of joining Britain and North America by cable was projected by Cyrus W Field in 1854 who obtained a charter from the Legislature of Newfoundland for a fifty-year exclusive right to the laying of a cable from Newfoundland to Great Britain and from the Continent of America to Newfoundland. Two years later the cable from Cape Breton in America to Newfoundland was completed. The first two attempts to lay a cable to Great Britain in 1857 and 1858 failed. A third attempt in 1858 was successful but the cable only lasted a few months. After the American Civil War, in 1865 another attempt was made which laid 1200 miles of cable before it snapped. Finally, in 1866 2000 miles of cable were laid and the Atlantic Cable was established. Research Atlantic Cable
An atmidometer is an instrument invented by Babington, used for measuring the evaporation from water, ice, snow etc. It consists of two glass or metal bulbs, one placed above the other, with which it communicates by a narrow neck. The lower one is weighted with lead or mercury, and the upper has on it a small glass or metal stem, with a scale graduated in fine increments. On the top of all there is a shallow pan. The instrument is immersed in a vessel of water through a circular hole in which the steam rises, distilled water is gradually poured into the pan above, causing it to sink to the point at which the zero of the steam is on a level with the cover of the vessel. As the water in the pan slowly evaporates, the steam slowly ascends, the amount of evaporation being indicated on the graduated scale. Research Atmidometer
Atmolysis is a method of separating the constituent gases of a compound gas (such as air) by causing it to pass through a vessel of porous material (such as graphite). The process was discovered by Graham and made known in 1863. Research Atmolysis
The atmometer is an instrument invented by Sir John Leslie for measuring the quantity of moisture exhaled in a given time from any humid surface. It consists of a very thin ball of porous-earthenware, from 25 to 75 mm in diameter, having a small neck firmly cemented to a long and rather wide tube of glass, to which is adapted a brass cap with a narrow collar of leather to fit closely. It is filled with distilled water, and its cap screwed tightly. It is then suspended out of doors in a situation where it is exposed freely to the action of the wind, but is sheltered from rain. As the water evaporates from the external surface of the ball, it transudes through its porous substance, and the waste is measured by the corresponding descent of the liquid in the stem. To test the amount of this descent there is a finely-graduated scale. Research Atmometer
In chemistry, an atomic number is a number, characteristic of an atom, that represents the number of protons in the nucleus of the atom. It indicates the location of an element in the periodic table. Research Atomic number
ATRAC is an abbreviation for Adaptive Transform Acoustic Coding, and is the digital audio encoding method used in minidiscs. The algorithm divides the 16 bit 44.1 KHz digital signal it receives into 52 sub-bands in the frequency domain (after a Fast Fourier Transform). A psycho-acoustic transfer function that takes advantage of the masking effect and the absolute hearing threshold then removes enough information to reduce the data stream to 1/5th of the original size. Each channel receives that treatment separately (the Sony MZ-1 portable MDrecorder features one ATRAC encoder/decoder chip per channel). Earlier versions of ATRAC, prior to version 3.5 were noisy, adding noise to recordings which could be heard during silent or very quiet passages in the audio recording. Later versions, 3.5 and onwards, are comparable to CD quality when listened to by the humanear. The first version of ATRAC had a frequency response up to 15 kHz, by version 3.5 that had increased to 18 kHz and version 4.5 reached 20 kHz. Research ATRAC
Attenuation (loss) is a term denoting a decrease in power between that transmitted and that received due to loss through equipment, lines, or other transmission devices. Usually expressed as a ratio in dB (decibels). Research Attenuation
In electronics, an attenuator is a network used to deliberately reduce the input signal to some piece of apparatus, or to reduce the degree of amplification of signals of particular frequencies. Research Attenuator
Attraction is the tendency of all material bodies, whether masses or particles, to approach each other, to unite, and to remain united. It was Isaac Newton that first adopted the theory of a universal attractive force, and determined its laws. When bodies tend to come together from sensible distances the tendency is termed either the attraction of gravitation, magnetism, or electricity, according to circumstances; when the attraction operates at insensible distances it is known as adhesion with respect to surfaces, as cohesion with respect to the particles of a body, and as affinity when the particles of different bodies tend together. It is by the attraction of gravitation that all bodies fall to the earth when unsupported. Research Attraction
The audiphone was an early hearing aid in use around 1900. It was an acoustic instrument by means of which deaf persons were enabled to hear. It consisted essentially of a fan-shaped plate of hardened caoutchouc, which was bent to a greater or less degree by strings, and was very sensitive to sound-waves. When used the up edge was pressed against the upper front teeth, with the convexity outward, and the sounds being collected were conveyed from the teeth to the auditory nerve without passing through the external ear. Research Audiphone
AutoCAD Release 10 is a two and three-dimensional computer aided drafting and design system. The product lets you define screens and optional pull-down menus and create parts libraries by drawing them, so the system can be geared to a specific requirement. The product is a general-purpose system suitable for a wide variety of applications including architectural and landscape drawings; drafting for mechanical, electrical, chemical, structural, and civil engineering; and printed circuitdesign. Drawing and editing features include move, copy, modify, dimension, scale, mirror, hatch, rotate, fill, and erase objects in a drawing. Repetitive patterns such as brick walls, memory arrays, or office components can be generated automatically. Colours and an unlimited number of layers may be used, allowing selective viewing or plotting of drawings as if on transparent overlays. The full bi-directional zoom facility allows you to work at any level of detail.
The ratio between the largest and smallest objects in a drawing can be over a trillion to one. An alignment grid can be displayed. Distances and areas can be calculated and displayed. Three-dimensional drawing capability, AutoCAD's most notable feature, lets you represent an object so it can be seen from any angle. AutoCAD Release 10 also features associative dimensioning, which automatically updates the dimensions of a drawing whenever an object is scaled, stretched, or rotated. Release 10 allows you to construct objects in CAD much as you would build a structure. The approach is modular; that is, each piece of the final drawing is created as a separate object. To build an office building, you define the plane for the front of the building, move to that plane or a view of that plane to draw, then move to the side defining a new plane, and soon until a complete two or three-dimensional structure stands. An analogy to drafting does not work because a drafting table cannot be situated in a three-dimensional plane.
AutoCAD Release 10 supports the Intel Above Board, which increases the speed at which large, complex drawings can be created and edited. It supports the Initial Graphics Exchange Standard (ICES, Version 2.0) for both input and output, so translations can be made between AutoCAD Release 10 and other systems supporting IGES. You can transfer AutoCAD Release 10 drawing files among four operating systems: PC or MSDOS, SunUNIX, DECVMS, and ApolloAEGIS. Research AutoCAD
AutoDesk Animator is an animation program that lets you create desktop videos for promotion and training. The program includes a number of animation techniques, painting functions, text effects, and file-import capabilities that provide a workbench for creating impressive diskette-based presentations. AutoDesk Animator incorporates five types of animation. Each is specifically designed to make creating and displaying animation sequences as impressive and easy as possible. The program provides traditional cell-by-cell animation capabilities. This technique displays a sequence of individual cells or images in rapid succession resulting in movement. Optical animation is best suited for animations where objects swoop across the screen. This technique uses complex combinations of spline paths and full 3D transformations along with other optical functions to maximise this type of effect.
Polymorphic tweening is an animation technique used to blend between two completely different shapes. It can be combined with optical animation to
add three-dimensional effects. Colour cycling transforms the colour of various screen locations. Titling provides full text animation for incorporating text in any part of a desktop video. Titling effects include multiple-direction scrolling and type-on, where each letter of words appears in rapid succession. Paint functions combine image processing inks with over 20 tools for detailed image creation and editing. The image processing inks affect the dispersion and quality of onscreen colours. The inks can be applied to saturate, strengthen, and define colours and create effects such as opaque, soften, gloss, glaze, emboss, scrape-through, sheen, and highlight. The combination of Animator's painting tools and image processing inks lets you control the sharpness, illumination, intensity, and glow of on-screen presentation colours more effectively than with any other PC product. Research AutoDesk Animator
Autoroute was a computerised map information system built using data from the Ordnance Survey. It allowed quick planning of the most suitable route between points in Great Britain. To use Autoroute, the user first needed to tell the package the travelling speed of the vehicle. Then, enter the start point and the desired destination, along with other places to visit - or places to avoid. Autoroute would then calculate the quickest and the shortest routes, which could be displayed as a colour map and then printed. A set of written directions could also be printed, including such detail as 'At GilletteComer, turn left onto A310 to Richmond.' The estimated journey time and total mileage were also calculated. Since Autoroute appeared in the 1980's, it has been superseded by numerous similar software packages, many of them available online through the Internet. Research Autoroute
AutoSketch is software for drawing. As easy to use as painting software, it includes many CAD features. However, unlike typical painting software, AutoSketch keeps track of objects. This means that shapes do not get lost in a sea of dots. When an object is manipulated, it maintains its integrity as a complete unit. The product was designed for users with less demanding drawing requirements such as office layouts, simple technical drawings, and flowcharts.
AutoSketch is the best starting point for individuals who may be interested in upgrading to AutoCAD later. In addition, AutoCAD users may find AutoSketch useful in the early drawing stages.
AutoSketch can draw lines, arcs, circles, points, polygons and spline curves (free-form shapes). All basic drawing shapes can be moved, copied, stretched, rotated, mirrored, or scaled. For example, by pointing and clicking, you can create an office layout where walls and furniture can be moved or adjusted on-screen.
AutoSketch uses a mouse with pull-down menus and dialog boxes. AutoSketch includes other CAD features such as dimensioning and measuring, snap and ortho alignment, layers, and line types. Text can be added at any point, at any angle, and can be any height or width.
AutoSketch also allows you to insert another AutoSketch drawing, so you can create a library of objects for future use. Research AutoSketch
Autotype is a former species of photographic print. A thin sheet of gelatine on paper was rendered sensitive to light by treatment with bichromate of potash, and then exposed under an ordinary photographic negative. The portions of gelatine affected by the light became insoluble, the remainder of the gelatine was then washed away, and the picture remained reproduced in the gelatine, there being slight elevations and depressions corresponding with the distribution of light and shade. This could then be printed from, but it was more common for use to be made of electrotypes or other reverses, from which impressions could more easily be taken. Research Autotype
An averruncator is a garden implement for pruning trees without a ladder, consisting of two blades similar to stout shears, one fixed rigidly to a long handle, and the other moved by a lever to which a cord passing over a pulley is attached. Research Averruncator
In chemistry, Avogadro's law is the law which states that equal volumes of all gases, at the same temperature and pressure, contain the same number of molecules. Research Avogadro's law
Awk is a UNIX interpreted language for massaging text data developed by Alfred Aho, Peter Weinberger, and Brian Kernighan (the name is formed from their initials). It is characterised by a C-like syntax, a declaration-free approach to variable typing and declarations, associative arrays, and field-oriented text processing. Research Awk
AWStats is a free http server log file analysis tool written in Perl. AWStats is very complicated to configure and operate, and the reports are produced in text requiring further processing by other software tools to produce management reports. Like some other http server reporting tools, AWStats seeks to make assumptions about human visitors to a web site and the duration of visits, even though this information is entirely guess work and not reliable, though is desired by management marketing departments. AWStats can be run remotely through a web site via a CGIinterface, which is a popular feature with managers of very small web sites on shared hosting, but does provide potential security issues. Research AWStats
The Axis PC is a computer from Atlantic Systems based upon the 333mhz Intel Celeron Processor and supplied with 64 mb of RAM, a 4.3 gb hard drive, an ATI 4 mb 3d AGP graphics card, CD-ROM player, sound card, 3.5 inch floppy disk drive and a 56K voice and faxmodem. Research Axis PC
The azimuth of a heavenly body is the arc of the horizon comprehended between the meridian of the observer and a vertical circle passing through the centre of the body. The azimuth and altitude give the exact position of the body. Research Azimuth
Abbreviations
SciTech
Research -ide
More information about 
