Permeation

The Permeation of films and membranes can be measured with any gas or liquid. The method uses a central module which is separated by the test film: the testing gas is fed on the one side of the cell and the permeated gas is carried to the detector by a sweep gas. The testing medium (liquid or gas) is situated in the inner white pipe and the permeate is collected in the space between the pipe and the glass wall. It is transported by a sweep gas (connected to the upper and lower joint) to an analyzing device.
Permeation in daily Life, example in
* Packaging the permeability of the package (materials, seals, closures, etc) needs to be matched with the sensitivity of the package contents and the specified shelf life. Some packages must have nearly hermetic Seals while other can (and sometimes must) be selectively permeable. Knowledge about the exact permeation rates is therefore essential.
* Tire Air pressure in tyres should decrease as slowly as possible. Therefore it is good to know which gas permeates least through the rubber wall.
* Insulating material: Water vapour permeation of insulating material is important as well as for submarine cables to protect the conductor from corrosion.
* Fuel System To meet legal regulations, it is essential to use barrier materials for fuel hoses and tanks.

LASER

The Word LASER is an acronym for light amplification by stimulated emission of radiation. LASER consist of a gain Medium inside a highly reflective optical cavity.as well as a means to supply energy to the gain medium. The gain medium is a material with properties that allow it to amplify light by stimulated emission. In its simplest form, a cavity consists of two mirrors arranged such that light bounces back and forth, each time passing through the gain medium. Typically one of the two mirrors, the output coupler partially transparent. The output laser beam is emitted through this mirror.Light of a specific wavelength that passes through the gain medium is increased in power the surrounding mirrors ensure that most of the light makes many passes through the gain medium, being amplified repeatedly. Part of the light that is between the mirrors (that is, within the cavity) passes through the partially transparent mirror and escapes as a beam of light. The process of supplying the energy required for the amplification is called pumping. The energy is typically supplied as an electrical current or as light at a different wavelength. Such light may be provided by a flash lamp.or perhaps another laser. Most practical lasers contain additional elements that affect properties such as the wavelength of the emitted light and the shape of the beam.
The types of LASER :
* Gas LASER using gases, e.g. He Ne, Carbon dioxide, Argon ion LASER
* Chemical LASER are powered by a chemical reaction, and can achieve high powers in continuous operation. For example, in the Hydrogen Flouride LASER
* Solid-state LASER, Solid state LASER Materials are commonly made by "doping" a crystalline solid host with ions that provide the required energy states. E.g. Ruby LASER

Absorption

Absorption in chemistry is a physical or chemical process in which atoms, ions or moleculs enter some bulk phase-gas, liquid,solid material.In many technologically important processes, the chemical absorption is used in place of the physical process, e.g. absorption of carbon dioxide by sodium hydroxide - such processes do not follow the Nernst partition law. In the case of gas absorption, one may calculate its concentration by using e.g. the ideal gas law. Alternatively one may use partial pressure instead of concentration. This is a different process from adsoption since the molecules are taken up by the volume, not by surface.

Cavitation

The word cavitation refers to the formation of vapor bubbles in regions of low pressure within the flow field of a liquid. In some respects, cavitation is similar to boiling, except that the latter is generally considered to occur as a result of an increase of temperature rather than a decrease of pressure. This difference in the direction of the state change in the phase diagram is more significant than might, at first sight, be imagined. It is virtually impossible to cause any rapid uniform change in temperature throughout a finite volume of liquid. Rather, temperature change most often occurs by heat transfer through a solid boundary. Hence, the details of the boiling process generally embrace the detailed interaction of vapor bubbles with a solid surface, and the thermal boundary layer on that surface. On the other hand, a rapid, uniform change in pressure in a liquid is commonplace and, therefore, the details of the cavitation process may differ considerably from those that occur in boiling. Cavitation can cause damage to the material surfaces close to the area where the bubbles collapse when they are convected into regions of higher pressure. Cavitation damage can be very expensive, and very difficult to eliminate. As the result of the cavitation can damage the surface of the blade of pump and can influence the performance of the pump.

Engine

Engine is mechanical device that converted force into motion. In most cases the work is supplied by exerting the torque, which is used to operate other machinery, generate electricity, pump water or compressed gases. Types of internal combustion engine include reciprocating engine, gas turbine, jet engine, turbo propeller engine, pulse jet, pulse detonation engine ,hot bulb engine, diesel engine, gasoline engine. Internal Combustion Engine is air breathing engine that use the oxygen in atmospheric air to burn the fuel carried rather than carrying an oxidiser as in rocket. Theoretically, this should result in a better spesific impulse than for rocket engine.