Infra red systems used in military

Military use infrared systems for night operation. Infra red systems used in military are provided with additional infra red illuminators. The advantages of these systems are low background contrast and limited range. In these systems, very fast and highly sensitive infra red detectors and electro-optical scanners are used. Display of infra red systems is very much similar to TV display. Two popular military infra red systems are infra red line scanner system and forward looking infra red system. Infra red line scanner system is used for the production of imagery of the terrain over flown. Here scanning of ground is carried out in narrow strips at right angles to the line of flight of the motion of aircraft followed by recording on a film. Forward looking infra red systems are often used with radar and can perform multi sensor operations. Some other infra red systems used in military are cyclone airbone infra red reconnaissance system, TA-7M2 aerial camera, FFV UNI reconnaissance pod, vinten airbone camera, Minisan camera, pave spike video film recorders, return beam vidicon camera, laser beam image reproducer and laser radar recorder.

Photorespiration

Plants undergo respiratory processes like animals and microorganisms. Plants can degrade carbohydrates by means of glycolysis and the Krebs cycle. Plants are also capable of catalyzing the general reactions of protein and amino acid metabolism. The organelles which support these reactions in plant cell are microsomes, mitochondria and cytoplasm. On illumination, plants undergo an additional metabolic activity.  This is known as photorespiration. This process is opposite to photosynthesis and decreases plant growth and crop yield. Photorespiration arises in plants when rubisco catalyzes the oxygenation of ribulose-1,5-biphosphate. Photorespiration produces adverse effects in crops like wheet, rice, legumes and sugar. Therefore for better yields, photorespiration has to be stopped. Researchers are struggling hard to develop methods to stop photorespiration and to enhance photosynthesis.

Igneous rocks

Magma is a material present in the earth's crust, at depths between 10-100 km. It is generated by local heating and melting of rocks. Magma upon cooling, solidifies and crystallizes into a mosaic of minerals. These minerals are known as igneous rocks. Volcanic eruptions can also produce igneous rocks. A volcano is created when magma is extruded onto the earth's surface. Magma which creates a volcano is known as extrusive igneous rocks. Magma which gets solidified below the surface of the earth is known as intrusive igneous rock. The minerals contained in igneous rocks are quartz, feldspar, muscovite, biotite and mafics. The most abundant igneous rocks are granite and basalt. Some other examples for igneous rocks are Rhyolite, andesite, dolerite, diorite, gabbro and porphyry.

Regulation of metabolism by the mediation of enzyme

A good coordination of anabolic and catabolic processes is required for the growth and maintenance of a cell. The working of metabolic machinery is dependent on enzyme catalyzed reactions. Thus a fine control of enzyme catalyzed reactions is essential in the regulation of metabolism. For the study of these reactions, we can make use of both prokaryotic and eukaryotic organisms. There exist four major steps in metabolic regulation. They are compartmentation of enzymes, differentiating pathways for catabolism and anabolism of a key substrate, interaction of substrates with change in kinetic factors and control of enzyme activity and enzyme concentration. The factors which control the actual functioning concentration of the enzymes in a cell are the rates of enzyme synthesis and degradation. A prokaryotic cell is a cell with a plasma membrane. The plasma membrane acts as a substrate for organic enzymes. In a eukaryotic cell, compartmentation of metabolic machineries occurs for very specific purposes. A plasma membrane is associated with this cell too which serves the purpose of selective transportation of important cations, anions and neutral compounds. Metabolic reactions are always reversible which makes use of two types of enzymes. One enzyme is used for forward reaction and the other one for backward reaction. These reactions are called opposing unidirectional reactions or substrate cycles.

Irrigation

Irrigation is defined as the artificial application of water to land for agricultural purposes. Irrigation is required when there is a deficiency in rainfall, non-uniform rainfall and augmentation of crop yields. It is also required in cash crops cultivation, orchards and gardens. Irrigation increases the food output, prevents damage through drought and floods and lowers production risks. Irrigation also increases the employment, value of land property, ground water storage etc. In a direct irrigation project, water is directly diverted from the river into the canal. Water is stored in a reservoir with the construction of a dam across the river in an indirect irrigation project. In the initial days, single purpose irrigation projects were announced and implemented by the various governments which were meant for a particular purpose. Now multipurpose irrigation projects are running which serves purposes like irrigation, navigation, power generation, flood control, domestic water supply, industrial water supply and tourism. Based on the financial return, irrigation projects are classified into three. They are productive, unproductive and protective. Irrigation potential is the aggregate area that can be irrigated in a year by the amount of water available at the field. India’s irrigation potential was only 19.5 M ha in 1947 which now crossed 120 M ha. The various systems of irrigation are gravity irrigation, lift irrigation, infiltrating irrigation, sewage irrigation and supplemental irrigation.

Designing dams

Dam is a water reservoir which is constructed across a river. It can be used for irrigation and power production. Water can be stored during the days of excess rainfall and can be released during other days to achieve continuous hydro power generation and irrigation. Dams are also effective in the protection from flood. Dams also serve some other purposes like navigation, fishing and recreation. Dams are also effective in improving climatic conditions and lowering river pollution. But dams can also harm in many ways. It may lead to the submergence of fertile lands, migration of population and disturbance in wildlife. The different requirements while choosing the dam site are there should be good runoff from the catchment area with minimum percolation losses, soil should be free from harmful soluble salts and minerals, runoff should be free from excessive slit load, there should be high and steep side hills, rock and soil erosion should be minimum, rock formation should have dip in the upstream direction, submergence of forest and cultivated lands should be minimum, site should be away from seismic zone and there should not be any vegetation and marshy land.

General purpose simulation system (GPSS)

General purpose simulation system is a process-oriented language originally designed by Geoffrey Gordon in 1961 which is used for discrete event modeling. GPSS, which was developed by IBM Corporation, is a very dynamic language. Modifications were being done on this language many times and hence exist many versions of this language now. Now GPSS become a multi-vendor language. GPSS is a very popular simulation language and it started with the advent of mainframe computers. GPSS is a superior language with in-built mechanism for the collection of data, analysis, production of tabulated output data and execution. In 1977, Henriksen developed a new language which is known as GPSS/H. This language is reported to be five times faster in execution time. GPSS/H offers some unique features like a real value clock for recording the simulation time, ability to read and write external files, enhanced control statements, increased number of mathematical functions, capability of generating unlimited number of independent random number series and capability of generating random variants from different probability distributions. A block-by-block construction model is used in GPSS. Block time is an integer which gives an idea about the number of units required to execute the action represented by the block.

Luminescence

Luminescence is the phenomenon in which a crystal absorbs energy and emits the energy back in the visible range. There are two varieties here-florescence and phosphorescence. Fluorescence is an instantaneous re-emission. Phosphorescence which is also known as afterglow takes a longer time to glow. Luminescence is greatly influenced by the presence of impurities and imperfections in the material. These impurities are called activators and introduce additional energy states in the bandgap of the material. These energy states are called recombination centers and traps. If the discrete energy states are located near the center of the bandgap, they are referred as recombination centers. All the other energy states in the bandgap are called traps. Thus a trap is an imperfection which is capable of capturing an electron or a hole. The existence of recombination centers and traps introduces a number of newer possible transitions in the semiconducting material. Luminescence finds applications in electroluminescent lamps, fluorescent tubes, cathode ray oscilloscopes and television displays. The phenomenon of luminescence may be classified into photoluminescence, cathodoluminescence, electroluminescence, chemiluminescence, thermoluminescence, triboluminescence and injection luminescence. Photoluminescence is produced by photons. Cathodoluminescence by high energy electrons, electroluminescence due to ac electric fields, chemiluminescence due to some chemical reactions, thermoluminescence by simulation at low temperatures, triboluminescence is due to mechanical energy and injection luminescence is due to forward biased p-n junction.

Manometers

Manometers are used for the measurement of pressure. In a single-tube manometer, a piezometer is connected to a pipe at the point where the static pressure of the fluid is to be measured. Piezometers are suitable for fluids under measurement. In a twin-tube manometer, two tubes of equal cross-section are connected together to form a U-tube. Both gas pressure and liquid pressure can be measured by using twin-tube manometers but care should be taken for not to mix or react chemically the liquid/gas under measurement with the manometric liquid. For low gauge pressures, water is taken as manometric liquid and in all other cases mercury is advisable. We can also employ a sealing liquid as a buffer to avoid reaction. The cistern type manometer requires only one reading while measurement. For the measurement of low differential pressures arising in gas-flow metering, ring-balance manometers are used. An electric displacement transducer is used in Bell-type manometers. Some other commonly used manometric liquids are transformer oil, dibutylphthalate, carbon tetrachloride and tetraboromethane. 

Welding processes

Various welding processes that can be used for joining the metal parts are solid phase welding, arc welding, resistance welding, thermit welding, ultrasonic welding, electron beam welding, laser beam welding and explosive welding. Solid state phase welding can be further classified into five categories- forge welding, butt welding, oxyacetylene pressure welding, flash butt welding and friction welding. In forge welding, the parts to be welded are heated in a furnace and then hammered together to form the weld. Electric current is used in Butt welding. An Oxyacetylene ring burner is used in oxyacetylene pressure welding. In flash butt welding, the parts are brought in contact with a light pressure and followed by the passage of an electric current. Heat due to friction is employed in friction welding.