The compressor narium minor is a small muscle attached at one end to the alar cartilage, and at the other end to the integument at the tip of the nose. All muscles of the nose are supplied by the facial nerve. Research Compressor Narium Minor
The compressor nasi (compressor naris) is a small, thin muscle with a triangular shape. It runs along the bridge of the nose forming the transverse portion of the nasalis mucle. It dilates the nostrils, the opposite action of the depressor nasi muscle. All muscles of the nose are supplied by the facial artery and innervated by the facial nerve (VII cranial nerve). Research Compressor Nasi
The depressor septi nasi is a short muscle that lies between the musclular structure and the mucousmembrane of the lip. It originates from the upper lip and extends upward along the median line of the lip to be inserted into the septum of the nose. It constricts the nostrils, the opposite action of the compressor nasi muscle. All muscles of the nose are innervated by the facial nerve (VII cranial artery) supplied by the facial artery. Research Depressor Septi Nasi
The nasalis muscle consists of two parts: the alar and the transverse. The alar is used when the nostrils are flared and runs along the side of the nose. The transverse runs diagonally and is used to wrinkle the nose. The nasalis is composed of three small muscles: the compressor nasi, the dilator naris posterior, and the depressor septi nasi. The compressor nasi is a small, thin muscle with a triangular shape. It runs along the bridge of the nose and depresses the cartilage and compresses the alae together. The depressor nasi is a short muscle that lies between the musclular structure and the mucousmembrane of the lip. It arises from the upper lip and extends to be inserted into the septum of the nose. It constricts the nares (nostrils) of the nose, the opposite action of the compressor nasi muscle. The dilatornares posterior is a small muscle that originates from the edge of the nasal notch and is inserted into the skin near the edge of the nostril. This muscle works with the dilator naris anterior, which is located in front of it,
to dilate the opening of the nares. All muscles of the nose are supplied by the facial nerve. Research Nasalis
The spincter urethra (compressor urethrae; constrictor urethrae; Guthrie's muscle; Wilson's muscle) originates from the ramus of the pubis and inserts in the median raphe behind and in front of the urethra. The flow of urine is controlled by muscles in the bladder wall and outlet. The sphincter urethra is innervated by the pudenal nerve. Research Sphincter Urethra
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
In audio engineering a compressor provides a form of automatic level control. It attenuates high levels, thus effectively reducing the dynamic range, making it much easier to control signals and set appropriate fader levels. Reducing the dynamic range also means that recording levels can be set higher, therefore improving the signal-to-noise performance. Limiting is an extreme form of compression, where the output signal is sharply attenuated so that it cannot exceed a particular level. Research Compressor
A gas-turbine is a form of engine in which a continuous stream of hot gases is directed against the blades of a turbine, causing it to turn. In most cases the gas, usually air, is first compressed in a compressor before passing into combustionchambers, where a portion of the gas is mixed with fuel and burned. The rest of the gas bypasses the combustion chamber and mixes with the hot gases emerging after combustion. This is then forced through nozzles to drive a turbine. Part of the power from this turbine is used to drive the compressor; the remaining power can be used in various ways, depending on the function of the engine: it may drive the propeller shaft of a turboprop aircraft or ship, the drive-shaft of a locomotive, or an electric generator. Alternatively, a turbine just big enough to drive the compressor can be used, and the remaining energy of the hot exhaust gases used to give a high-speed exhaust jet and hence a forward thrust; this is the jet engine. Gas-turbines are used in electricity generation for standby and peak-load service, in portable power plants, and in combined-cycle power generation. The high power-to-weight ratio of gas-turbines has led to their use in aeroplanes, and also in diesel locomotives and naval vessels. Research Gas-Turbine
A jet engine is a form of gas-turbine engine used in aircraft, in which the thrust is generated by a jet of exhaust gas discharged from a nozzle at the rear of the engine.
Jet engines were developed concurrently in the UK and in Germany. Whittle's centrifugal flow turbojet was patented in 1930 and first tested later in the same year. The first jet aeroplane to fly was the German Heinkel He 178 in 1939, powered by an engine designed by von Ohain. In a turbojet, air is taken into the engine and compressed, then mixed with fuel and burnt. The combustion gases then pass through a turbine, the power from which drives the compressor, after which the remaining energy in the gas is converted to kinetic energy in the exhaust cone and propelling nozzle, and ejected as a high- velocity jet. The configuration of the propelling nozzle is critical for maximum efficiency at a given speed. Turbojets are most efficient at high speeds: for speeds below 800 km/h a more efficient type of engine is the turboprop. This works on the same principle as the turbojet, but most of the energy of the combustion gases drives the turbine, which is used to power a propeller as well as the compressor. A small amount of forward thrust is also obtained from the
exhaust gases. A major use of turboprop engines is in helicopters. In the bypass jet engine two air compressors, one low- pressure and one high-pressure, are used. After passage through the first, low-pressure compressor, part of the air intake bypasses the combustion chamber and turbine. The combination of this cold air jet and the hot exhaust jet gives a much larger mass of air and therefore increased thrust, without an increase in fuel consumption. This principle is taken even further in the turbofan engine, which incorporates a large fan to accelerate still more air outside the engine proper, as well as using the bypass principle. Current research priorities include the reduction of polluting emissions from jet engines, and the development of ceramic engine components, which are lighter and can work at higher temperatures than metals. Research Jet Engine
A ram-jet is a jet engine with no compressor, in which air is drawn in and compressed by the forward motion of the engine. It has no moving parts, and is essentially a shaped duct, consisting of an intake section which acts as a compressor by slowing down the entering air, a combustion chamber where fuel is added and burnt, and a nozzle section in which the stream of hot gas is accelerated to give a high-speed exhaust jet. The jet provides propulsive thrust in a manner similar to that of a rocket. The ram-jet has to be launched at high speed, so has found limited application. Research Ram-Jet
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Compressor Narium Minor
