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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.
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10Base2 is an Ethernet cabling 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 Ethernet cabling 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.
127.0.0.1 is the loop back network connection IP address for TCP/IP networks.
1vs Personal Internet Engine is both a Web and offline browser and a search engine for the IBM PC. 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.
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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.
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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 computer package 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.
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3SI is an integrated accounting system for the IBM PC, 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.
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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 alphanumeric cell phone or pager.
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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 Unix TAR 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.
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A & B Leads is a designation of leads derived from the midpoints of the two pairs comprising a 4-wire circuit.
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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.
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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.
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A/UX was an implementation of UNIX by Apple for the Macintosh computer. A/UX was based on AT&T's UNIX System V with Berkeley extensions.
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In computer terms A20 refers to the first 64KB of extended memory (A0 to A19) of a PC known as the 'high memory area'.
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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.
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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.
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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.
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The ABC Process was a method of purifying sewage which derived its name from the articles used: sulphate of alumina, blood, charcoal and clay.
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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'.
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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 achromatic lens. 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 apparent displacement 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 orbital velocity 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.
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Abietic acid (sylvic acid) is a texturizer in soaps. It is obtained from pine resin.
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Abietin is a resin obtained from Strasburg turpentine or Canada balsam. It is without taste or smell, is insoluble in water, but soluble in alcohol (especially at the boiling point), in strong acetic acid, and in ether.
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Abiogenesis is a term applied by Thomas Huxley in 1870 to the theory that living matter may be produced from non-living.
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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 acid rain.
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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.
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Absolute is a mathematical function that always returns a positive number. In computing it is commonly represented as 'ABS'.
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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 carbon atom 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 carbon atom 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 carbon atom. 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 carbon atom. 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.
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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.
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Absolute Temperature is temperature based on the absolute zero of temperature (-273 degrees Celsius or 0 degrees Kelvin) at which a body possesses no thermal energy.
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In chemistry, absolute zero is the temperature, 273 degrees below the zero of the centigrade scale, at which all molecular motion ceases.
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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.
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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.
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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 cell membrane. In animals, for example, soluble food material is absorbed into the circulatory system through cells lining the alimentary canal. In plants, water and mineral salts are absorbed from the soil by the roots.
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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.
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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.
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The abyssal zone is the region of an ocean between 2000 and 6000 meters 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.
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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.
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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.
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Accelerated motion describes a motion with a continually increasing velocity.
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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.
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In electronics, an accelerating grid is an accelerating electrode in the form of a grid.
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Acceleration is the rate at which a moving body increases in velocity.
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An accelerator is a device for increasing speed.
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In computing, an accelerator board is an add-in board that replaces the existing CPU with a faster CPU.
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An accelerator valve is a thermionic valve employed as a particle accelerator.
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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.
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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 tone arm 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.
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Access Charge is a cost assessed to users for connection ability to the interexchange, interstate message toll telephone 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.
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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 '#')
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An access line is a telephone circuit connecting a customer location to a public network switching centre.
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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.
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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.
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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.
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An accretion disc is a disc-shaped rotating mass formed by gravitational attraction.
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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.
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AceNotes is a notes manager for the IBM PC 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.
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Acetal is a colourless liquid formed by oxidation of alcohol.
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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 pyridine bases, 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 silver mirrors, and to harden gelatine 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.
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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.
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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.
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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.
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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 cellulose acetate 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 human blood 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.
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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.
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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.
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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 chromatic aberration of the former, and a satisfactory image will be produced. Telescopes, microscopes, etc, in which the glasses are thus composed are called achromatic.
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An achromatic telescope is a telescope in which colour is got rid of. They were invented by John Dollond around 1753.
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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.
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Acid Buf is a trade name for calcified seaweed - lithothamnium calcareum.
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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.
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In telecommunications, ACK is the 'acknowledge' character in many data codes; used most commonly for an affirmative response of correct receipt.
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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.
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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.
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The aclinic is a magnetic equator.
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Acology is the science of remedies.
Research Acology
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
The term acoustic refers to hearing.
Research Acoustic
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 meters per second; through water at the rate of about 1433 meters.
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.
The properties of sound were mathematically investigated by Bacon and Galileo, but it remained for Isaac Newton, Lagrange, Euler, Laplace, Holmholtz, etc to further the science.
Research Acoustics
Acridine is an organic compound with the formulae c13h9n used in dyes and drugs.
Research Acridine
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 dam foundations, 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
An actinide is an element with an atomic number between 89 and 103.
Research Actinide
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
Actinium is a radioactive trivalent element that resembles lanthanum in chemical properties and is found especially in pitchblende. It has the symbol Ac.
Research Actinium
An actinometer is an instrument for measuring heat radiation.
Research Actinometer
In mechanics, the term action refers to an effective motion or mechanism as for example the breech
action of a gun.
Research Action
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 Lord Byron, 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
In chemistry, addition reaction is a reaction in which a reagent adds to a carbon-carbon double or triple bond.
Research Addition reaction
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 typewriter ribbon 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
Adenine is a base derived from purine; one of the five found in nucleic acids, where it is generally paired with thymine or uracil.
Research Adenine
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
An adhesive is a sticky substance.
Research Adhesive
Adipocere is a substance in dead bodies formed by decomposition of fatty acids when exposed to moisture.
Research Adipocere
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 HTML design 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 crisp PostScript 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 move anchor 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 WYSIWYG HTML 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 copper telephone 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
In chemistry, adsorption is a process in which molecules or ions adhere to the surface of a solid.
Research Adsorption
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 host computer is not connected to the internet when the program is running, no 'call home' is made. If the host computer 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
An aerial is a receiving or radiating device used in radio communications.
Research Aerial
Aero metal is a light, strong alloy of aluminium, zinc and copper,
Research Aero Metal
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 aerolite is a stony meteorite.
Research Aerolite
Aerolithology is the science of aerolites (stony meteorites).
Research Aerolithology
Aerology is the science concerned with the study of atmospheric conditions away from ground level.
Research Aerology
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
Aerometry is the science of measuring the air, including the doctrine of its pressure, elasticity, rarefaction, and condensation.
Research Aerometry
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
Aestho-physiology is the science of sensation in relation to nervous action.
Research Aestho-physiology
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 invisible aqueous vapour 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 diminish affinity 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
Agma is a trade name for calcined magnesite.
Research Agma
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
Agonistics is a former name for the science of athletic combats, or contests in public games.
Research Agonistics
Agriculture is the science or art of farming. That is cultivating the soil, harvesting crops and rearing animals.
Research Agriculture
Agronomics is the science of the distribution and management of land.
Research Agronomics
Agronomy is the science of soil management and crop production.
Research Agronomy
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 UNIX stream (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
The air is a mixture of gasses enveloping the earth.
Research Air
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 silken thread 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 per cent 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, occ |
Abbreviations
SciTech
