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Air purifier
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An air purifier or air cleaner is a device which removes contaminants from the air in a room. These devices are marketed as being beneficial to allergy sufferers and asthmatics. Air purifiers may also be used in industry to remove impurities such as CO2 from air before processing, pressure swing adsorbers or other adsorption techniques are typically used for this. In 1830, a patent was awarded to Charles Anthony Deane, a long leather hose attached to the rear of the helmet was to be used to supply air, the original concept being that it would be pumped using a double bellows. A short pipe allowed breathed air to escape, the garment was to be constructed from leather or airtight cloth, secured by straps. In the 1860s, John Stenhouse filed two patents applying the absorbent properties of charcoal to air purification, thereby creating the first practical respirator. A few years later, John Tyndall invented an improvement to the firemans respirator, dust, pollen, pet dander, mold spores, and dust mite feces can act as allergens, triggering allergies in sensitive people. Smoke particles and volatile compounds can pose a risk to health. Exposure to various such as VOCs increases the likelihood of experiencing symptoms of sick building syndrome. Air purifiers are becoming capable of capturing a greater number of bacterial, virus. Several different processes of varying effectiveness can be used to purify air, thermodynamic sterilization - This technology uses heat sterilization via a ceramic core with micro capillaries, which are heated to 200 °C. It is claimed that 99. 9% of microbiological particles - bacteria, viruses, dust mite allergens, mold, the air passes through the ceramic core by the natural process of air convection, and is then cooled using heat transfer plates and released. TSS is not a technology, as it does not trap or remove particles. TSS is claimed not to emit harmful by-products and also reduces the concentration of ozone in the atmosphere, ultraviolet germicidal irradiation - UVGI can be used to sterilize air that passes UV lamps via forced air. Air purification UVGI systems can be freestanding units with shielded UV lamps that use a fan to force air past the UV light, other systems are installed in forced air systems so that the circulation for the premises moves micro-organisms past the lamps. Key to this form of sterilization is placement of the UV lamps, for example, forced air systems by design impede line-of-sight, thus creating areas of the environment that will be shaded from the UV light. However, a UV lamp placed at the coils and drainpan of cooling system will keep micro-organisms from forming in these naturally damp places. The most effective method for treating the air rather than the coils is in-line duct systems, filter - based purification traps airborne particles by size exclusion
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Fiber
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Fiber or fibre is a natural or synthetic substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials, the strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene. Natural fibers develop or occur in the shape, and include those produced by plants, animals. Plant fibers are employed in the manufacture of paper and textile, wood fiber, distinguished from vegetable fiber, is from tree sources. Forms include groundwood, lacebark, thermomechanical pulp, and bleached or unbleached kraft or sulfite pulps, animal fibers consist largely of particular proteins. Instances are silkworm silk, spider silk, sinew, catgut, wool, sea silk and hair such as wool, mohair and angora, fur such as sheepskin, rabbit, mink, fox, beaver. Mineral fibers include the asbestos group, asbestos is the only naturally occurring long mineral fiber. Six minerals have been classified as asbestos including chrysotile of the serpentine class, short, fiber-like minerals include wollastonite and palygorskite. Instances are collagen family of proteins, tendon, muscle proteins like actin, cell proteins like microtubules and many others, spider silk, sinew, man-made or chemical fibers are fibers whose chemical composition, structure, and properties are significantly modified during the manufacturing process. Man-made fibers consist of regenerated fibers and synthetic fibers, the earliest semi-synthetic fiber is the cellulose regenerated fiber, rayon. Most semi-synthetic fibers are cellulose regenerated fibers, cellulose fibers are a subset of man-made fibers, regenerated from natural cellulose. The cellulose comes from sources, rayon from tree wood fiber, Modal from beech trees, bamboo fiber from bamboo, seacell from seaweed. In the production of fibers, the cellulose is reduced to a fairly pure form as a viscous mass. Therefore, the process leaves few characteristics distinctive of the natural source material in the finished products. Some examples are, rayon bamboo fiber Lyocell, a brand of rayon Modal, historically, cellulose diacetate and -triacetate were classified under the term rayon, but are now considered distinct materials. Synthetic come entirely from materials such as petrochemicals, unlike those man-made fibers derived from such natural substances as cellulose or protein. Metallic fibers can be drawn from ductile metals such as copper, gold or silver and extruded or deposited from more brittle ones, such as nickel, carbon fibers are often based on oxydized and via pyrolysis carbonized polymers like PAN, but the end product is almost pure carbon. Silicon carbide fibers, where the polymers are not hydrocarbons but polymers
3.
Porous
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Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1, or as a percentage between 0 and 100%. Strictly speaking, some measure the accessible void, the total amount of void space accessible from the surface. There are many ways to test porosity in a substance or part, the term porosity is used in multiple fields including pharmaceutics, ceramics, metallurgy, materials, manufacturing, earth sciences, soil mechanics and engineering. Void fraction usually varies from location to location in the flow channel and it fluctuates with time and its value is usually time averaged. In separated flow, it is related to flow rates of the gas and the liquid phase. It is defined by the ratio, ϕ = V V V T where VV is the volume of void-space and VT is the total or bulk volume of material, both the mathematical symbols ϕ and n are used to denote porosity. Porosity is a fraction between 0 and 1, typically ranging from less than 0.01 for solid granite to more than 0.5 for peat and it may also be represented in percent terms by multiplying the fraction by 100. The porosity of a rock, or sedimentary layer, is an important consideration when attempting to evaluate the potential volume of water or hydrocarbons it may contain. Sedimentary porosity is a function of many factors, including but not limited to, rate of burial, depth of burial, the nature of the connate fluids. The principal complication is that there is not a direct proportionality between porosity and hydraulic conductivity but rather an inferred proportionality, there is a clear proportionality between pore throat radii and hydraulic conductivity. Also, there tends to be a proportionality between pore throat radii and pore volume, if the proportionality between pore throat radii and porosity exists then a proportionality between porosity and hydraulic conductivity may exist. Well sorted materials have higher porosity than similarly sized poorly sorted materials, for tables of common porosity values for earth materials, see the further reading section in the Hydrogeology article. Consolidated rocks potentially have more complex dual porosities, as compared with alluvial sediment and this can be split into connected and unconnected porosity. Connected porosity is more easily measured through the volume of gas or liquid that can flow into the rock, porosity is the ratio of pore volume to its total volume. Porosity is controlled by, rock type, pore distribution, cementation, diagenetic history, porosity is not controlled by grain size, as the volume of between-grain space is related only to the method of grain packing. Rocks normally decrease in porosity with age and depth of burial, tertiary age Gulf Coast sandstones are in general more porous than Cambrian age sandstones. There are exceptions to this rule, usually because of the depth of burial and thermal history, porosity of surface soil typically decreases as particle size increases. This is due to soil formation in finer textured surface soils when subject to soil biological processes
4.
Particulates
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Atmospheric particulate matter – also known as particulate matter or particulates – are microscopic solid or liquid matter suspended in the Earths atmosphere. The term aerosol commonly refers to the mixture, as opposed to the particulate matter alone. Sources of particulate matter can be man-made or natural and they have impacts on climate and precipitation that adversely affect human health. The smaller PM2.5 were particularly deadly, with a 36% increase in lung cancer per 10 μg/m3 as it can penetrate deeper into the lungs, some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes, coal combustion in developing countries is the primary method for heating homes and supplying energy. The composition of aerosols and particles depends on their source, wind-blown mineral dust tends to be made of mineral oxides and other material blown from the Earths crust, this particulate is light-absorbing. In addition, sea spray aerosols may contain organic compounds, which influence their chemistry, Secondary particles derive from the oxidation of primary gases such as sulfur and nitrogen oxides into sulfuric acid and nitric acid. The gases from which they originate—may have an origin and a natural biogenic origin. In the presence of ammonia, secondary aerosols often take the form of ammonium salts and this is mainly because the presence of sulfate and nitrate causes the aerosols to increase to a size that scatters light effectively. Organic matter can be primary or secondary, the latter part deriving from the oxidation of VOCs. Organic matter influences the atmospheric radiation field by both scattering and absorption, another important aerosol type is elemental carbon, this aerosol type includes strongly light-absorbing material and is thought to yield large positive radiative forcing. Organic matter and elemental carbon together constitute the carbonaceous fraction of aerosols, Secondary organic aerosols, tiny tar balls resulting from combustion products of internal combustion engines, have been identified as a danger to health. The chemical composition of the aerosol directly affects how it interacts with solar radiation, the chemical constituents within the aerosol change the overall refractive index. The refractive index will determine how light is scattered and absorbed. The particles are hygroscopic due to the presence of sulfur, and SO2 is converted to sulfate when high humidity and this causes the reduced visibility and yellow color. Aerosol particles of natural origin tend to have a larger radius than human-produced aerosols such as particle pollution, the false-color maps in the third image on this page show where there are natural aerosols, human pollution, or a mixture of both, monthly. Most of the Southern Hemisphere is covered by ocean, where the largest source of aerosols is natural sea salt from dried sea spray. Because land is concentrated in the Northern Hemisphere, the amount of small aerosols from fires, over land, patches of large-radius aerosols appear over deserts and arid regions, most prominently, the Sahara Desert in north Africa and the Arabian Peninsula, where dust storms are common
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Dust
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Dust is fine particles of matter. It generally consists of particles in the atmosphere that come from sources such as soil, dust lifted by weather, volcanic eruptions. House dust mites are present indoors wherever humans live, positive tests for dust mite allergies are extremely common among people with asthma. Dust mites are microscopic arachnids whose primary food is dead skin cells. They and their feces and other allergens they produce are major constituents of house dust and they are generally found on the floor and other surfaces until disturbed. It could take somewhere between twenty minutes and two hours for dust mites to settle back down out of the air, Dust mites are a nesting species that prefers a dark, warm, and humid climate. They flourish in mattresses, bedding, upholstered furniture, and carpets and their feces include enzymes that are released upon contact with a moist surface, which can happen when a person inhales, and these enzymes can kill cells within the human body. House dust mites did not become a problem until humans began to use textiles, such as western style blankets and clothing. Atmospheric or wind-borne dust, also known as aeolian dust, comes from arid and dry regions where high velocity winds are able to remove mostly silt-sized material, Dust in the atmosphere is produced by saltation and sandblasting of sand-sized grains, and it is transported through the troposphere. This airborne dust is considered an aerosol and once in the atmosphere, saharan dust in particular can be transported and deposited as far as the Caribbean and the Amazon basin, and may affect air temperatures, cause ocean cooling, and alter rainfall amounts. Dust in the Middle East has been a historic phenomenon, recently, because of climate change and the escalating process of desertification, the problem has worsened dramatically. As a multi-factor phenomenon, there is not yet a consensus on the sources or potential solutions to the problem. In Iran, the dust is already affecting more than 5 million people directly, in the province of Khuzestan it has led to the severe reduction of air quality. The amount of pollutants in the air has surpassed more than 50 times the normal level several times in a year, recently, initiatives such as Project-Dust have been established to directly study the Middle Eastern dust. Dust kicked up by vehicles traveling on roads may make up 33% of air pollution, road dust consists of deposits of vehicle exhausts and industrial exhausts, particles from tire and brake wear, dust from paved roads or potholes, and dust from construction sites. Road dust is a significant source contributing to the generation and release of particulate matter into the atmosphere. Control of road dust is a significant challenge in urban areas, road dust may be suppressed by mechanical methods like street sweeper vehicles equipped with vacuum cleaners, vegetable oil sprays, or with water sprayers. Improvements in automotive engineering have reduced the amount of PM10s produced by road traffic, coal dust is responsible for the lung disease known as pneumoconiosis, including black lung disease that occurs among coal miners
6.
Pollen
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Pollen is a fine to coarse powdery substance comprising pollen grains which are male microgametophytes of seed plants, which produce male gametes. If pollen lands on a compatible pistil or female cone, it germinates, individual pollen grains are small enough to require magnification to see detail. The study of pollen is called palynology and is useful in paleoecology, paleontology, archaeology. Pollen in plants is used for transferring haploid male genetic material from the anther of a flower to the stigma of another in cross-pollination. In a case of self-pollination, this takes place from the anther of a flower to the stigma of the same flower. Pollen itself is not the male gamete, each pollen grain contains vegetative cells and a generative cell. In flowering plants the vegetative tube cell produces the pollen tube, pollen is produced in the microsporangia in the male cone of a conifer or other gymnosperm or in the anthers of an angiosperm flower. Pollen grains come in a variety of shapes, sizes. Pollen grains of pines, firs, and spruces are winged, the smallest pollen grain, that of the forget-me-not, is around 6 µm in diameter. Wind-borne pollen grains can be as large as about 90–100 µm, in angiosperms, during flower development the anther is composed of a mass of cells that appear undifferentiated, except for a partially differentiated dermis. As the flower develops, four groups of cells form within the anther. The fertile sporogenous cells are surrounded by layers of cells that grow into the wall of the pollen sac. Some of the cells grow into nutritive cells that supply nutrition for the microspores that form by meiotic division from the sporogenous cells, in a process called microsporogenesis, four haploid microspores are produced from each diploid sporogenous cell, after meiotic division. After the formation of the four microspores, which are contained by callose walls, the exine is what is preserved in the fossil record. Two basic types of microsporogenesis are recognised, simultaneous and successive, in simultaneous microsporogenesis meiotic steps I and II are completed prior to cytokinesis, whereas in successive microsporogenesis cytokinesis follows. While there may be a continuum with intermediate forms, the type of microsporogenesis has systematic significance, the predominant form amongst the monocots is successive, but there are important exceptions. During microgametogenesis, the unicellular microspores undergo mitosis and develop into mature microgametophytes containing the gametes, in some flowering plants, germination of the pollen grain may begin even before it leaves the microsporangium, with the generative cell forming the two sperm cells. Except in the case of submerged aquatic plants, the mature pollen grain has a double wall
7.
Mold
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A mold or mould is a fungus that grows in the form of multicellular filaments called hyphae. In contrast, fungi that can adopt a single-celled growth habit are called yeasts, molds are a large and taxonomically diverse number of fungal species in which the growth of hyphae results in discoloration and a fuzzy appearance, especially on food. The network of these tubular branching hyphae, called a mycelium, is considered a single organism, the hyphae are generally transparent, so the mycelium appears like very fine, fluffy white threads over the surface. Cross-walls may delimit connected compartments along the hyphae, each containing one or multiple, the dusty texture of many molds is caused by profuse production of asexual spores formed by differentiation at the ends of hyphae. The mode of formation and shape of spores is traditionally used to classify molds. Many of these spores are colored, making the much more obvious to the human eye at this stage in its life-cycle. Molds are considered to be microbes and do not form a taxonomic or phylogenetic grouping. In the past, most molds were classified within the Deuteromycota, molds cause biodegradation of natural materials, which can be unwanted when it becomes food spoilage or damage to property. They also play important roles in biotechnology and food science in the production of foods, beverages, antibiotics, pharmaceuticals. There are thousands of species of molds, which have diverse life-styles including saprotrophs, mesophiles, psychrophiles and thermophiles. They all require moisture for growth and some live in aquatic environments, like all fungi, molds derive energy not through photosynthesis but from the organic matter on which they live, utilising heterotrophy. Typically, molds secrete hydrolytic enzymes, mainly from the hyphal tips and these enzymes degrade complex biopolymers such as starch, cellulose and lignin into simpler substances which can be absorbed by the hyphae. In this way molds play a role in causing decomposition of organic material. Many molds also synthesise mycotoxins and siderophores which, together with lytic enzymes, molds can also grow on stored food for animals and humans, making the food unpalatable or toxic and are thus a major source of food losses and illness. Many strategies for food preservation are to prevent or slow growth as well as growth of other microbes. Molds reproduce by producing large numbers of spores, which may contain a single nucleus or be multinucleate. Mold spores can be asexual or sexual, many species can produce both types, other mold spores have slimy sheaths and are more suited to water dispersal. Mold spores are spherical or ovoid single cells, but can be multicellular
8.
Bacteria
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Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods, Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, Bacteria also live in symbiotic and parasitic relationships with plants and animals. Most bacteria have not been characterised, and only half of the bacterial phyla have species that can be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology, There are typically 40 million bacterial cells in a gram of soil and a million bacterial cells in a millilitre of fresh water. There are approximately 5×1030 bacteria on Earth, forming a biomass which exceeds that of all plants, Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of bodies and bacteria are responsible for the putrefaction stage in this process. In March 2013, data reported by researchers in October 2012, was published and it was suggested that bacteria thrive in the Mariana Trench, which with a depth of up to 11 kilometres is the deepest known part of the oceans. Other researchers reported related studies that microbes thrive inside rocks up to 580 metres below the sea floor under 2.6 kilometres of ocean off the coast of the northwestern United States. According to one of the researchers, You can find microbes everywhere—theyre extremely adaptable to conditions, the vast majority of the bacteria in the body are rendered harmless by the protective effects of the immune system, though many are beneficial particularly in the gut flora. However several species of bacteria are pathogenic and cause diseases, including cholera, syphilis, anthrax, leprosy. The most common fatal diseases are respiratory infections, with tuberculosis alone killing about 2 million people per year. In developed countries, antibiotics are used to treat infections and are also used in farming, making antibiotic resistance a growing problem. Once regarded as constituting the class Schizomycetes, bacteria are now classified as prokaryotes. Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and these evolutionary domains are called Bacteria and Archaea. The ancestors of modern bacteria were unicellular microorganisms that were the first forms of life to appear on Earth, for about 3 billion years, most organisms were microscopic, and bacteria and archaea were the dominant forms of life. In 2008, fossils of macroorganisms were discovered and named as the Francevillian biota, however, gene sequences can be used to reconstruct the bacterial phylogeny, and these studies indicate that bacteria diverged first from the archaeal/eukaryotic lineage. Bacteria were also involved in the second great evolutionary divergence, that of the archaea, here, eukaryotes resulted from the entering of ancient bacteria into endosymbiotic associations with the ancestors of eukaryotic cells, which were themselves possibly related to the Archaea
9.
Atmosphere of Earth
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The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earths gravity. The atmosphere of Earth protects life on Earth by absorbing solar radiation, warming the surface through heat retention. By volume, dry air contains 78. 09% nitrogen,20. 95% oxygen,0. 93% argon,0. 04% carbon dioxide, and small amounts of other gases. Air also contains an amount of water vapor, on average around 1% at sea level. The atmosphere has a mass of about 5. 15×1018 kg, the atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The Kármán line, at 100 km, or 1. 57% of Earths radius, is used as the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around 120 km, several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition. The study of Earths atmosphere and its processes is called atmospheric science, early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann. The three major constituents of air, and therefore of Earths atmosphere, are nitrogen, oxygen, water vapor accounts for roughly 0. 25% of the atmosphere by mass. The remaining gases are often referred to as gases, among which are the greenhouse gases, principally carbon dioxide, methane, nitrous oxide. Filtered air includes trace amounts of other chemical compounds. Various industrial pollutants also may be present as gases or aerosols, such as chlorine, fluorine compounds, sulfur compounds such as hydrogen sulfide and sulfur dioxide may be derived from natural sources or from industrial air pollution. In general, air pressure and density decrease with altitude in the atmosphere, however, temperature has a more complicated profile with altitude, and may remain relatively constant or even increase with altitude in some regions. In this way, Earths atmosphere can be divided into five main layers, excluding the exosphere, Earth has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere. It extends from the exobase, which is located at the top of the thermosphere at an altitude of about 700 km above sea level, to about 10,000 km where it merges into the solar wind. This layer is composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen. The atoms and molecules are so far apart that they can travel hundreds of kilometers without colliding with one another, thus, the exosphere no longer behaves like a gas, and the particles constantly escape into space. These free-moving particles follow ballistic trajectories and may migrate in and out of the magnetosphere or the solar wind, the exosphere is located too far above Earth for any meteorological phenomena to be possible
10.
Absorption (chemistry)
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In chemistry, absorption is a physical or chemical phenomenon or a process in which atoms, molecules or ions enter some bulk phase – gas, liquid or solid material. This is a different process from adsorption, since molecules undergoing absorption are taken up by the volume, a more general term is sorption, which covers absorption, adsorption, and ion exchange. Absorption is a condition in which something takes in another substance, for some examples of this effect, see liquid-liquid extraction. It is possible to extract from one phase to another a solute without a chemical reaction. Examples of such solutes are noble gases and osmium tetroxide, the process of absorption means that a substance captures and transforms energy. The absorbent distributes the material it captures throughout whole and adsorbent only distributes it through the surface and this equation is valid if concentrations are not too large and if the species x does not change its form in any of the two phases 1 or 2. In the case of gas absorption, one may calculate its concentration by using, e. g. the Ideal gas law, in alternative fashion, one may use partial pressures instead of concentrations. Absorption is a process that may be chemical or physical, chemical absorption or reactive absorption is a chemical reaction between the absorbed and the absorbing substances. Sometimes it combines with physical absorption and this type of absorption depends upon the stoichiometry of the reaction and the concentration of its reactants
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Catalysis
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Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst. In most cases, reactions occur faster with a catalyst because they require less activation energy, furthermore, since they are not consumed in the catalyzed reaction, catalysts can continue to act repeatedly. Often only tiny amounts are required in principle, in the presence of a catalyst, less free energy is required to reach the transition state, but the total free energy from reactants to products does not change. A catalyst may participate in multiple chemical transformations, the effect of a catalyst may vary due to the presence of other substances known as inhibitors or poisons or promoters. Catalyzed reactions have an activation energy than the corresponding uncatalyzed reaction, resulting in a higher reaction rate at the same temperature. However, the mechanics of catalysis is complex. Usually, the catalyst participates in this slowest step, and rates are limited by amount of catalyst, in heterogeneous catalysis, the diffusion of reagents to the surface and diffusion of products from the surface can be rate determining. A nanomaterial-based catalyst is an example of a heterogeneous catalyst, analogous events associated with substrate binding and product dissociation apply to homogeneous catalysts. Although catalysts are not consumed by the reaction itself, they may be inhibited, deactivated, in heterogeneous catalysis, typical secondary processes include coking where the catalyst becomes covered by polymeric side products. Additionally, heterogeneous catalysts can dissolve into the solution in a system or sublimate in a solid–gas system. The production of most industrially important chemicals involves catalysis, similarly, most biochemically significant processes are catalysed. Research into catalysis is a field in applied science and involves many areas of chemistry, notably organometallic chemistry. Catalysis is relevant to aspects of environmental science, e. g. the catalytic converter in automobiles. Many transition metals and transition metal complexes are used in catalysis as well, Catalysts called enzymes are important in biology. A catalyst works by providing a reaction pathway to the reaction product. The rate of the reaction is increased as this route has a lower activation energy than the reaction route not mediated by the catalyst. The disproportionation of hydrogen peroxide creates water and oxygen, as shown below,2 H2O2 →2 H2O + O2 This reaction is preferable in the sense that the reaction products are more stable than the starting material, though the uncatalysed reaction is slow. In fact, the decomposition of hydrogen peroxide is so slow that hydrogen peroxide solutions are commercially available and this reaction is strongly affected by catalysts such as manganese dioxide, or the enzyme peroxidase in organisms
12.
Charcoal
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Charcoal is a lightweight, black residue, consisting of carbon and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances. Charcoal is usually produced by slow pyrolysis- the heating of wood or other substances in the absence of oxygen, the whole pile is covered with turf or moistened clay. The firing is begun at the bottom of the flue, the success of the operation depends upon the rate of the combustion. The operation is so delicate that it was left to colliers. They often lived alone in small huts in order to tend their wood piles, for example, in the Harz Mountains of Germany, charcoal burners lived in conical huts called Köten which are still much in evidence today. The massive production of charcoal was a cause of deforestation. The increasing scarcity of easily harvested wood was a factor behind the switch to fossil fuel equivalents, mainly coal. Charcoal made at 300 °C is brown, soft and friable, and readily inflames at 380 °C, made at higher temperatures it is hard and brittle, in Finland and Scandinavia, the charcoal was considered the by-product of wood tar production. The best tar came from pine, thus pinewoods were cut down for tar pyrolysis, the residual charcoal was widely used as substitute for metallurgical coke in blast furnaces for smelting. Tar production led to deforestation, it has been estimated all Finnish forests are younger than 300 years. The end of tar production at the end of the 19th century resulted in rapid re-forestation, the charcoal briquette was first invented and patented by Ellsworth B. A. Zwoyer of Pennsylvania in 1897 and was produced by the Zwoyer Fuel Company. The process was popularized by Henry Ford, who used wood. Ford Charcoal went on to become the Kingsford Company, Charcoal has been made by various methods. The traditional method in Britain used a clamp and this is essentially a pile of wooden logs leaning against a chimney. The chimney consists of 4 wooden stakes held up by some rope, the logs are completely covered with soil and straw allowing no air to enter. It must be lit by introducing some burning fuel into the chimney, if the soil covering gets torn by the fire, additional soil is placed on the cracks. Once the burn is complete, the chimney is plugged to prevent air from entering, the true art of this production method is in managing the sufficient generation of heat, and its transfer to wood parts in the process of being carbonised. A strong disadvantage of this method is the huge amount of emissions that are harmful to human health
13.
Odor
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An odor or odour or fragrance is caused by one or more volatilized chemical compounds, generally at a very low concentration, that humans or other animals perceive by the sense of olfaction. Odors are also commonly called scents, which can refer to both pleasant and unpleasant odors, the terms fragrance and aroma are used primarily by the food and cosmetic industry to describe a pleasant odor, and are sometimes used to refer to perfumes, and to describe floral scent. In contrast, malodor, stench, reek, and stink are used specifically to describe unpleasant odor, the term smell is used for both pleasant and unpleasant odors. In the United Kingdom, odour refers to scents in general, the sense of smell gives rise to the perception of odors, mediated by the olfactory nerve. The olfactory receptor cells are present in the olfactory epithelium. There are millions of olfactory receptor neurons that act as sensory signaling cells, each neuron has cilia in direct contact with air. The olfactory nerve is considered the smell mediator, the axon connects the brain to the external air, odorous molecules act as a chemical stimulus. Molecules bind to receptor proteins extended from cilia, initiating an electric signal, thus, by using a chemical that binds to copper in the mouse nose, so that copper wasn’t available to the receptors, the authors showed that the mice couldnt detect the thiols. However, these also found that MOR244-3 lacks the specific metal ion binding site suggested by Suslick. When the signal reaches a threshold, the fires, sending a signal traveling along the axon to the olfactory bulb. Interpretation of the begins, relating the smell to past experiences. The olfactory bulb acts as a station connecting the nose to the olfactory cortex in the brain. Olfactory information is processed and projected through a pathway to the central nervous system. Odor sensation usually depends on the concentration available to the olfactory receptors, the olfactory system does not interpret a single compound, but instead the whole odorous mix, not necessarily corresponding to concentration or intensity of any single constituent. The widest range of odors consists of compounds, although some simple compounds not containing carbon, such as hydrogen sulfide. The perception of an effect is a two-step process. First, there is the part, the detection of stimuli by receptors in the nose. The stimuli are processed by the region of the brain which is responsible for olfaction
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Air pollution
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Air pollution occurs when harmful substances including particulates and biological molecules are introduced into Earths atmosphere. It may cause diseases, allergies or death in humans, it may cause harm to other living organisms such as animals and food crops. Human activity and natural processes can both generate air pollution, indoor air pollution and poor urban air quality are listed as two of the worlds worst toxic pollution problems in the 2008 Blacksmith Institute Worlds Worst Polluted Places report. According to the 2014 WHO report, air pollution in 2012 caused the deaths of around 7 million people worldwide, an air pollutant is a substance in the air that can have adverse effects on humans and the ecosystem. The substance can be particles, liquid droplets, or gases. A pollutant can be of natural origin or man-made, pollutants are classified as primary or secondary. Primary pollutants are usually produced from a process, such as ash from a volcanic eruption, other examples include carbon monoxide gas from motor vehicle exhaust, or the sulfur dioxide released from factories. Secondary pollutants are not emitted directly, rather, they form in the air when primary pollutants react or interact. Ground level ozone is a prominent example of a secondary pollutant, some pollutants may be both primary and secondary, they are both emitted directly and formed from other primary pollutants. Substances emitted into the atmosphere by human activity include, Carbon dioxide - Debate continues over whether carbon dioxide should be classified as an atmospheric pollutant, because of its role as a greenhouse gas it has been described as the leading pollutant and the worst climate pollution. Against this it is argued that carbon dioxide is a component of the atmosphere, essential for plant life. This question of terminology has practical effects, for example as determining whether the U. S. Clean Air Act is deemed to regulate CO2 emissions, CO2 increase in earths atmosphere has been accelerating. Sulfur oxides - particularly sulfur dioxide, a compound with the formula SO2. SO2 is produced by volcanoes and in industrial processes. Coal and petroleum often contain sulfur compounds, and their combustion generates sulfur dioxide, further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain. This is one of the causes for concern over the impact of the use of these fuels as power sources. Nitrogen oxides - Nitrogen oxides, particularly nitrogen dioxide, are expelled from high temperature combustion and they can be seen as a brown haze dome above or a plume downwind of cities. Nitrogen dioxide is a compound with the formula NO2
15.
Ventilation (architecture)
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Ventilation is the intentional introduction of outside air into a space. The intentional introduction of air can be categorized as either mechanical ventilation. Mechanical ventilation uses fans to drive the flow of air into a building. This may be accomplished by pressurization, or by depressurization, many mechanically ventilated buildings use a combination of both, with the ventilation being integrated into the HVAC system. Natural ventilation is the passive flow of outside air into a building through planned openings. Natural ventilation does not require mechanical systems to move air, it relies entirely on passive physical phenomena, such as diffusion, wind pressure. Mixed mode ventilation systems use mechanical and natural processes. The mechanical and natural components may be used in conjunction with other or separately at different times of day or season of the year. Since the natural component can be affected by environmental conditions it may not always provide an appropriate amount of ventilation. In this case, mechanical systems may be used to supplement or to regulate the naturally driven flow, in many instances, ventilation for indoor air quality is simultaneously beneficial for the control of thermal comfort. At these times, it can be useful to increase the rate of ventilation beyond the minimum required for air quality. Two examples include air-side economizer strategies and ventilation pre-cooling, in other instances, ventilation for indoor air quality contributes to the need for - and energy use by - mechanical heating and cooling equipment. In hot and humid climates, dehumidification of ventilation air can be an energy intensive process. Although ventilation is a component to maintaining good indoor air quality. In scenarios where outdoor pollution would deteriorate indoor air quality, other treatment devices such as filtration may also be necessary. In kitchen ventilation systems, or for laboratory fume hoods, the design of effective effluent capture can be more important than the amount of ventilation in a space. The ability for a system to pollution is described as its ventilation effectiveness. Ventilation should be considered for its relationship to venting for appliances and combustion equipment such as heaters, furnaces, boilers
16.
Aircraft
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An aircraft is a machine that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the lift of an airfoil. The human activity that surrounds aircraft is called aviation, crewed aircraft are flown by an onboard pilot, but unmanned aerial vehicles may be remotely controlled or self-controlled by onboard computers. Aircraft may be classified by different criteria, such as type, aircraft propulsion, usage. Each of the two World Wars led to technical advances. Consequently, the history of aircraft can be divided into five eras, Pioneers of flight, first World War,1914 to 1918. Aviation between the World Wars,1918 to 1939, Second World War,1939 to 1945. Postwar era, also called the jet age,1945 to the present day, aerostats use buoyancy to float in the air in much the same way that ships float on the water. They are characterized by one or more large gasbags or canopies, filled with a relatively low-density gas such as helium, hydrogen, or hot air, which is less dense than the surrounding air. When the weight of this is added to the weight of the aircraft structure, a balloon was originally any aerostat, while the term airship was used for large, powered aircraft designs – usually fixed-wing. In 1919 Frederick Handley Page was reported as referring to ships of the air, in the 1930s, large intercontinental flying boats were also sometimes referred to as ships of the air or flying-ships. – though none had yet been built, the advent of powered balloons, called dirigible balloons, and later of rigid hulls allowing a great increase in size, began to change the way these words were used. Huge powered aerostats, characterized by an outer framework and separate aerodynamic skin surrounding the gas bags, were produced. There were still no fixed-wing aircraft or non-rigid balloons large enough to be called airships, then several accidents, such as the Hindenburg disaster in 1937, led to the demise of these airships. Nowadays a balloon is an aerostat and an airship is a powered one. A powered, steerable aerostat is called a dirigible, sometimes this term is applied only to non-rigid balloons, and sometimes dirigible balloon is regarded as the definition of an airship. Non-rigid dirigibles are characterized by a moderately aerodynamic gasbag with stabilizing fins at the back and these soon became known as blimps. During the Second World War, this shape was adopted for tethered balloons, in windy weather
17.
Satellite
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In the context of spaceflight, a satellite is an artificial object which has been intentionally placed into orbit. Such objects are called artificial satellites to distinguish them from natural satellites such as Earths Moon. In 1957 the Soviet Union launched the worlds first artificial satellite, since then, about 6,600 satellites from more than 40 countries have been launched. According to a 2013 estimate,3,600 remained in orbit, of those, about 1,000 were operational, the rest have lived out their useful lives and become space debris. Approximately 500 operational satellites are in orbit,50 are in medium-Earth orbit. A few large satellites have been launched in parts and assembled in orbit. Over a dozen space probes have been placed into orbit around other bodies and become artificial satellites to the Moon, Mercury, Venus, Mars, Jupiter, Saturn, a few asteroids, Satellites are used for many purposes. Common types include military and civilian Earth observation satellites, communications satellites, navigation satellites, weather satellites, Space stations and human spacecraft in orbit are also satellites. Satellite orbits vary greatly, depending on the purpose of the satellite, well-known classes include low Earth orbit, polar orbit, and geostationary orbit. A launch vehicle is a rocket that throws a satellite into orbit, usually it lifts off from a launch pad on land. Some are launched at sea from a submarine or a mobile maritime platform, Satellites are usually semi-independent computer-controlled systems. Satellite subsystems attend many tasks, such as power generation, thermal control, telemetry, attitude control, the first fictional depiction of a satellite being launched into orbit was a short story by Edward Everett Hale, The Brick Moon. The idea surfaced again in Jules Vernes The Begums Fortune, in 1903, Konstantin Tsiolkovsky published Exploring Space Using Jet Propulsion Devices, which is the first academic treatise on the use of rocketry to launch spacecraft. He calculated the speed required for a minimal orbit. In 1928, Herman Potočnik published his book, The Problem of Space Travel — The Rocket Motor. He described the use of orbiting spacecraft for observation of the ground, in a 1945 Wireless World article, the English science fiction writer Arthur C. Clarke described in detail the possible use of communications satellites for mass communications. He suggested that three geostationary satellites would provide coverage over the entire planet, the first artificial satellite was Sputnik 1, launched by the Soviet Union on October 4,1957, and initiating the Soviet Sputnik program, with Sergei Korolev as chief designer. This in turn triggered the Space Race between the Soviet Union and the United States, Sputnik 1 helped to identify the density of high atmospheric layers through measurement of its orbital change and provided data on radio-signal distribution in the ionosphere
18.
Space Shuttle
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The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by the U. S. National Aeronautics and Space Administration, as part of the Space Shuttle program. Its official program name was Space Transportation System, taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development, the first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982. Five complete Shuttle systems were built and used on a total of 135 missions from 1981 to 2011, the Shuttle fleets total mission time was 1322 days,19 hours,21 minutes and 23 seconds. Shuttle components included the Orbiter Vehicle, a pair of solid rocket boosters. The Shuttle was launched vertically, like a rocket, with the two SRBs operating in parallel with the OVs three main engines, which were fueled from the ET. The SRBs were jettisoned before the vehicle reached orbit, and the ET was jettisoned just before orbit insertion, at the conclusion of the mission, the orbiter fired its OMS to de-orbit and re-enter the atmosphere. The orbiter then glided as a spaceplane to a landing, usually at the Shuttle Landing Facility of KSC or Rogers Dry Lake in Edwards Air Force Base. After landing at Edwards, the orbiter was back to the KSC on the Shuttle Carrier Aircraft. The first orbiter, Enterprise, was built in 1976 for use in Approach, four fully operational orbiters were initially built, Columbia, Challenger, Discovery, and Atlantis. Of these, two were lost in accidents, Challenger in 1986 and Columbia in 2003, with a total of fourteen astronauts killed. A fifth operational orbiter, Endeavour, was built in 1991 to replace Challenger, the Space Shuttle was retired from service upon the conclusion of Atlantiss final flight on July 21,2011. Nixons post-Apollo NASA budgeting withdrew support of all components except the Shuttle. The vehicle consisted of a spaceplane for orbit and re-entry, fueled by liquid hydrogen and liquid oxygen tanks. The first of four orbital test flights occurred in 1981, leading to operational flights beginning in 1982, all launched from the Kennedy Space Center, Florida. The system was retired from service in 2011 after 135 missions, the program ended after Atlantis landed at the Kennedy Space Center on July 21,2011. Major missions included launching numerous satellites and interplanetary probes, conducting space science experiments, the first orbiter vehicle, named Enterprise, was built for the initial Approach and Landing Tests phase and lacked engines, heat shielding, and other equipment necessary for orbital flight. A total of five operational orbiters were built, and of these and it was used for orbital space missions by NASA, the US Department of Defense, the European Space Agency, Japan, and Germany. The United States funded Shuttle development and operations except for the Spacelab modules used on D1, sL-J was partially funded by Japan
19.
Fiberglass
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Fiberglass is a type of fiber-reinforced plastic where the reinforcement fiber is specifically glass fiber. The glass fiber may be arranged, flattened into a sheet. The plastic matrix may be a polymer matrix – most often based on thermosetting polymers such as epoxy, polyester resin. The glass fibers are made of various types of glass depending upon the fiberglass use and these glasses all contain silica or silicate, with varying amounts of oxides of calcium, magnesium, and sometimes boron. To be used in fiberglass, glass fibers have to be made very low levels of defects. Fiberglass is a lightweight material and is used for many products. Although it is not as strong and stiff as composites based on fiber, it is less brittle. Its bulk strength and weight are also better than many metals, other common names for fiberglass are glass-reinforced plastic, glass-fiber reinforced plastic or GFK. Because glass fiber itself is referred to as fiberglass, the composite is also called fiberglass reinforced plastic. This article will adopt the convention that fiberglass refers to the glass fiber reinforced composite material. A patent for this method of producing glass wool was first applied for in 1933, Owens joined with the Corning company in 1935 and the method was adapted by Owens Corning to produce its patented fibreglas in 1936. Originally, fibreglas was a wool with fibers entrapping a great deal of gas, making it useful as an insulator. A suitable resin for combining the fibreglass with a plastic to produce a material was developed in 1936 by du Pont. The first ancestor of modern polyester resins is Cyanamids resin of 1942, peroxide curing systems were used by then. With the combination of fiberglass and resin the gas content of the material was replaced by plastic and this reduced the insulation properties to values typical of the plastic, but now for the first time the composite showed great strength and promise as a structural and building material. Confusingly, many glass fiber composites continued to be called fiberglass, ray Greene of Owens Corning is credited with producing the first composite boat in 1937, but did not proceed further at the time due to the brittle nature of the plastic used. In 1939 Russia was reported to have constructed a boat of plastic materials. The first car to have a body was a 1946 prototype of the Stout Scarab
20.
Air ioniser
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An air ioniser is a device that uses high voltage to ionise air molecules. Negative ions, or anions, are particles with one or more extra electrons, cations are positive ions missing one or more electrons, resulting in a net positive charge. Most commercial air purifiers are designed to generate negative ions, another type of air ioniser is the electrostatic discharge ioniser used to neutralise static charge. In 2002, Cecil Alfred Coppy Laws was credited with being the inventor of the domestic air ioniser in an obituary in The Independent newspaper, Air ionisers have been used to eliminate the occurrence of air-borne bacterial infections and to reduce static electricity buildup in electronics. Air ionisers are used in air purifiers to remove particles from air, airborne particles are attracted to the electrode in an effect similar to static electricity. These ions are de-ionised by seeking earthed conductors, such as walls, to increase the efficiency of this process, some commercial products provide such surfaces within the device. Positive and negative ions produced by air conditioning systems have also found by a manufacturer to inactivate viruses including influenza. The SARS epidemic fueled the desire for personal ionisers in East Asia, there are no specific standards for these devices. Ionisers are distinct from ozone generators, although both devices operate in a similar way, ionisers use electrostatically charged plates to produce positively or negatively charged gas ions that particulate matter sticks to in an effect similar to static electricity. Even the best ionisers will also produce an amount of ozone—triatomic oxygen. Ozone generators are optimised to attract an extra oxygen ion to an O2 molecule, at concentrations that do not exceed public health standards, ozone has been found to have little potential to remove indoor air contaminants. At high concentrations ozone can be toxic to bacteria. Ozone is a toxic and extremely reactive gas. A higher daily average than 0.1 ppm is not recommended and can damage the lungs, a number of studies have been carried out on negative ion generators. Some studies show that the ozone generated can exceed guidelines in small, one study showed that ozone can react with other constituents, namely cleaning agents to increase pollutants such as formaldehyde. Consumer Reports, a non-profit US-based product-testing magazine, reported in October 2003 that air ionisers do not perform to high enough standards compared to conventional HEPA filters, the exception was a combination unit that used a fan to move air while ionizing it. In response to report, The Sharper Image, a manufacturer of air ionisers. Consumer Reports gave the Ionic Breeze and other units a fail because they have a low Clean Air Delivery Rate
21.
Static electricity
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Static electricity is an imbalance of electric charges within or on the surface of a material. The charge remains until it is able to move away by means of a current or electrical discharge. Static electricity is named in contrast with current electricity, which flows through wires or other conductors, a static electric charge can be created whenever two surfaces contact and separate, and at least one of the surfaces has a high resistance to electric current. The familiar phenomenon of a static shock–more specifically, an electrostatic discharge–is caused by the neutralization of charge, materials are made of atoms that are normally electrically neutral because they contain equal numbers of positive charges and negative charges. The phenomenon of static electricity requires a separation of positive and negative charges, when two materials are in contact, electrons may move from one material to the other, which leaves an excess of positive charge on one material, and an equal negative charge on the other. When the materials are separated they retain this charge imbalance and this is known as the triboelectric effect and results in one material becoming positively charged and the other negatively charged. The polarity and strength of the charge on a material once they are separated depends on their positions in the triboelectric series. The triboelectric effect is the cause of static electricity as observed in everyday life. Contact-induced charge separation causes your hair to stand up and causes static cling, pressure-induced charge separation Applied mechanical stress generates a separation of charge in certain types of crystals and ceramics molecules. Heat-induced charge separation Heating generates a separation of charge in the atoms or molecules of certain materials, all pyroelectric materials are also piezoelectric. The atomic or molecular properties of heat and pressure response are closely related, charge-induced charge separation A charged object brought close to an electrically neutral object causes a separation of charge within the neutral object. Charges of the same polarity are repelled and charges of the opposite polarity are attracted, as the force due to the interaction of electric charges falls off rapidly with increasing distance, the effect of the closer charges is greater and the two objects feel a force of attraction. The effect is most pronounced when the object is an electrical conductor as the charges are more free to move around. Careful grounding of part of an object with a charge separation can permanently add or remove electrons, leaving the object with a global. This process is integral to the workings of the Van de Graaff generator, removing or preventing a buildup of static charge can be as simple as opening a window or using a humidifier to increase the moisture content of the air, making the atmosphere more conductive. Air ionizers can perform the same task, fabric softeners and dryer sheets used in washing machines and clothes dryers are an example of an antistatic agent used to prevent and remove static cling. Many semiconductor devices used in electronics are particularly sensitive to static discharge, conductive antistatic bags are commonly used to protect such components. People who work on circuits that contain these devices often ground themselves with an antistatic strap
22.
Internal combustion engine
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An internal combustion engine is a heat engine where the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine, the force is applied typically to pistons, turbine blades, rotor or a nozzle. This force moves the component over a distance, transforming chemical energy into mechanical energy. The first commercially successful internal combustion engine was created by Étienne Lenoir around 1859, firearms are also a form of internal combustion engine. Working fluids can be air, hot water, pressurized water or even liquid sodium, ICEs are usually powered by energy-dense fuels such as gasoline or diesel, liquids derived from fossil fuels. While there are many applications, most ICEs are used in mobile applications and are the dominant power supply for vehicles such as cars, aircraft. Typically an ICE is fed with fossil fuels like natural gas or petroleum products such as gasoline, there is a growing usage of renewable fuels like biodiesel for compression ignition engines and bioethanol or methanol for spark ignition engines. Hydrogen is sometimes used, and can be made from fossil fuels or renewable energy. Various scientists and engineers contributed to the development of internal combustion engines, in 1791, John Barber developed a turbine. In 1794 Thomas Mead patented a gas engine, also in 1794 Robert Street patented an internal combustion engine, which was also the first to use liquid fuel, and built an engine around that time. In 1798, John Stevens built the first American internal combustion engine, in 1807, Swiss engineer François Isaac de Rivaz built an internal combustion engine ignited by electric spark. In 1823, Samuel Brown patented the first internal combustion engine to be applied industrially, in 1860, Belgian Jean Joseph Etienne Lenoir produced a gas-fired internal combustion engine. In 1864, Nikolaus Otto patented the first atmospheric gas engine, in 1872, American George Brayton invented the first commercial liquid-fuelled internal combustion engine. In 1876, Nikolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, in 1879, Karl Benz patented a reliable two-stroke gas engine. In 1892, Rudolf Diesel developed the first compressed charge, compression ignition engine, in 1926, Robert Goddard launched the first liquid-fueled rocket. In 1939, the Heinkel He 178 became the worlds first jet aircraft, at one time, the word engine meant any piece of machinery — a sense that persists in expressions such as siege engine. A motor is any machine that produces mechanical power, traditionally, electric motors are not referred to as Engines, however, combustion engines are often referred to as motors. In boating an internal combustion engine that is installed in the hull is referred to as an engine, reciprocating piston engines are by far the most common power source for land and water vehicles, including automobiles, motorcycles, ships and to a lesser extent, locomotives
23.
Air compressor
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An air compressor is a device that converts power into potential energy stored in pressurized air. By one of methods, an air compressor forces more and more air into a storage tank. When tank pressure reaches its upper limit the air compressor shuts off, the compressed air, then, is held in the tank until called into use. The energy contained in the air can be used for a variety of applications, utilizing the kinetic energy of the air as it is released. When tank pressure reaches its limit, the air compressor turns on again. Positive-displacement compressors work by forcing air into a chamber whose volume is decreased to compress the air, once the maximum pressure is reached, a port or valve opens and air is discharged into the outlet system from the compression chamber. Common types of positive displacement compressors are, Piston-type, air compressors use this principle by pumping air into an air chamber through the use of the constant motion of pistons and they use one-way valves to guide air into a cylinder chamber, where the air is compressed. Rotary screw compressors, use positive-displacement compression by matching two helical screws that, when turned, guide air into a chamber, whose volume is decreased as the screws turn. Vane compressors, use a rotor with varied blade placement to guide air into a chamber. A type of compressor that delivers a fixed volume of air at high pressures, dynamic displacement air compressors include centrifugal compressors and axial compressors. In these types, a rotating component imparts its energy to the air which is eventually converted into pressure energy. These use centrifugal force generated by an impeller to accelerate and then decelerate captured air. Due to adiabatic heating, air compressors require some method of disposing of waste heat, generally this is some form of air- or water-cooling, although some compressors may be cooled by oil and the atmospheric changes also considered during cooling of compressors. Most air compressors either are reciprocating piston type, rotary vane or rotary screw, centrifugal compressors are common in very large applications. There are two types of air compressors pumps, oil-lubed and oil-less. The oil-less system has more technical development, but is expensive, louder. The oil-less system also delivers air of better quality, the most common types of air compressors are, electric or gas/diesel powered compressors. The power of a compressor is measured in HP and CFM, the gallon size of the tank specifies the volume of compressed air available
24.
Filter paper
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Filter paper is a semi-permeable paper barrier placed perpendicular to a liquid or air flow. It is used to separate fine substances from liquids or air, filter paper comes in various porosities and grades depending on the applications it is meant for. The important parameters are wet strength, porosity, particle retention, flow rate, compatibility, efficiency, there are two mechanisms of filtration with paper, volume and surface. By volume filtration the particles are caught in the bulk of the filter paper, by surface filtration the particles are caught on the paper surface. Filter paper is used because even a small piece of filter paper will absorb a significant volume of liquid The raw materials are different paper pulps. The pulp may be from softwood, hardwood, fiber crops, for high quality filters, dissolving pulp and mercerised pulp are used. Most filter papers are made on paper machines. For laboratory filters the machines may be as small as 50 cm width, the paper is often crêped to improve porosity. The filter papers may also be treated with reagents or impregnation to get the right properties, the main application for air filters are combustion air to engines. The filter papers are transformed into filter cartridges, which then is fitted to a holder, the construction of the cartridges mostly requires that the paper is stiff enough to be self-supporting. A paper for air filters needs to be porous and have a weight of 100 -200 g/m2. Normally particularly long fibrous pulp that is mercerised is used to get these properties, the paper is normally impregnated to improve the resistance to moisture. Some heavy duty qualities are made to be rinsed and thereby extend the life of the filter, coffee filters of paper are made from about 100 g/m2 crêped paper. The crêping allows the coffee to flow freely between the filter and the filtration funnel, the raw materials for the filter paper are coarse long fiber, often from fast growing trees. Both bleached and unbleached qualities are made, coffee filters are made in different shapes and sizes to fit into different holders. Important parameters are strength, compatibility, efficiency and capacity, the paper used for fuel filters is a crêped paper with controlled porosity, which is pleated and wound to cartridges. The raw material for filter paper used in filters are made of a mixture of hardwood and softwood fibres. The basis weight of the paper is 50 -80 g/m2, filter papers are widely used in laboratory experiments across many different fields, from biology to chemistry
25.
Foam
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A foam is a substance formed by trapping pockets of gas in a liquid or solid. A bath sponge and the head on a glass of beer are examples of foams, in most foams, the volume of gas is large, with thin films of liquid or solid separating the regions of gas. Solid foams can be closed-cell or open-cell, in closed-cell foam, the gas forms discrete pockets, each completely surrounded by the solid material. In open-cell foam, gas pockets connect to each other, a bath sponge is an example of an open-cell foam, water easily flows through the entire structure, displacing the air. A camping mat is an example of a foam, gas pockets are sealed from each other so the mat cannot soak up water. Foams are examples of dispersed media, when the principal scale is small, i. e. for a very fine foam, this dispersed medium can be considered a type of colloid. Foam can also refer to something that is analogous to foam, such as foam, polyurethane foam, XPS foam, polystyrene, phenolic. A foam is, in cases, a multi-scale system. One scale is the bubble, material foams are typically disordered and have a variety of bubble sizes, at larger sizes, the study of idealized foams is closely linked to the mathematical problems of minimal surfaces and three-dimensional tessellations, also called honeycombs. The Weaire–Phelan structure is considered the best possible unit cell of a perfectly ordered foam, at lower scale than the bubble is the thickness of the film for metastable foams, which can be considered a network of interconnected films called lamellae. Ideally, the lamellae connect in triads and radiate 120° outward from the connection points, an even lower scale is the liquid–air interface at the surface of the film. Most of the time this interface is stabilized by a layer of amphiphilic structure, often made of surfactants, particles, or more complex associations. Several conditions are needed to produce foam, there must be mechanical work, surface active components that reduce the tension. To create foam, work is needed to increase the surface area, one of the ways foam is created is through dispersion, where a large amount of gas is mixed with a liquid. A more specific method of dispersion involves injecting a gas through a hole in a solid into a liquid, if this process is completed very slowly, then one bubble can be emitted from the orifice at a time as shown in the picture below. The force working against the force is the surface tension force, which is F s =2 r π γ, where γ is the surface tension. As more air is pushed into the bubble, the buoyancy force grows quicker than the tension force. Thus, detachment occurs when the force is large enough to overcome the surface tension force
26.
Cotton
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Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus Gossypium in the family of Malvaceae. The fiber is almost pure cellulose, under natural conditions, the cotton bolls will tend to increase the dispersal of the seeds. The plant is a native to tropical and subtropical regions around the world, including the Americas, Africa. The greatest diversity of wild species is found in Mexico, followed by Australia. Cotton was independently domesticated in the Old and New Worlds, the fiber is most often spun into yarn or thread and used to make a soft, breathable textile. Current estimates for world production are about 25 million tonnes or 110 million bales annually, China is the worlds largest producer of cotton, but most of this is used domestically. The United States has been the largest exporter for many years, in the United States, cotton is usually measured in bales, which measure approximately 0.48 cubic meters and weigh 226.8 kilograms. Cotton cultivation in the region is dated to the Indus Valley Civilization, the Indus cotton industry was well-developed and some methods used in cotton spinning and fabrication continued to be used until the industrialization of India. Between 2000 and 1000 BC cotton became widespread across much of India, for example, it has been found at the site of Hallus in Karnataka dating from around 1000 BC. Cotton fabrics discovered in a cave near Tehuacán, Mexico have been dated to around 5800 BC, the domestication of Gossypium hirsutum in Mexico is dated between 3400 and 2300 BC. Cotton was grown upriver, made into nets, and traded with fishing villages along the coast for supplies of fish. The Spanish who came to Mexico and Peru in the early 16th century found the people growing cotton and this may be a reference to tree cotton, Gossypium arboreum, which is a native of the Indian subcontinent. According to the Columbia Encyclopedia, Cotton has been spun, woven and it clothed the people of ancient India, Egypt, and China. Hundreds of years before the Christian era, cotton textiles were woven in India with matchless skill, in Iran, the history of cotton dates back to the Achaemenid era, however, there are few sources about the planting of cotton in pre-Islamic Iran. The planting of cotton was common in Merv, Ray and Pars of Iran, in Persian poets poems, especially Ferdowsis Shahname, there are references to cotton. Marco Polo refers to the products of Persia, including cotton. John Chardin, a French traveler of the 17th century who visited the Safavid Persia, during the Han dynasty, cotton was grown by Chinese peoples in the southern Chinese province of Yunnan. Mohamed Ali Pasha accepted the proposition and granted himself the monopoly on the sale and export of cotton in Egypt, and later dictated cotton should be grown in preference to other crops
27.
Intake
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An intake or inlet is an opening on a car or aircraft body capturing air for operation of an internal combustion engine. An ideal intake system should increase the velocity of the air until it travels into the chamber, while minimizing turbulence. However, in aircraft, particularly supersonic aircraft, the purpose of the intake is to slow, early automobile intake systems were simple air inlets connected directly to carburetors. The first air filter was implemented on the 1915 Packard Twin Six, the modern automobile air intake system has three main parts, an air filter, mass flow sensor, and throttle body. Some modern intake systems can be complex, and often include specially-designed intake manifolds to optimally distribute air. Many cars today now include a silencer to minimize the noise entering the cabin, silencers impede air flow and create turbulence which reduce total power, so performance enthusiasts often remove them. All the above is accomplished by flow testing on a flow bench in the port design stage. Cars with turbochargers or superchargers which provide pressurized air to the engine usually have highly refined intake systems to improve performance dramatically, production cars have specific-length air intakes to cause the air to vibrate and buffet at a specific frequency to assist air flow into the combustion chamber. These designs became more complex as aircraft speeds increased to Mach 3.0 and Mach 3.2, design points for the XB-70, the inlet is part of the fuselage or part of the nacelle. Cold air intake Warm air intake Short ram air intake Ram-air intake Intake ramp Inlet manifold
28.
Gas turbine
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A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a turbine. The basic operation of the gas turbine is similar to that of the power plant except that the working fluid is air instead of water. Fresh atmospheric air flows through a compressor that brings it to higher pressure, energy is then added by spraying fuel into the air and igniting it so the combustion generates a high-temperature flow. This high-temperature high-pressure gas enters a turbine, where it expands down to the exhaust pressure, the turbine shaft work is used to drive the compressor and other devices such as an electric generator that may be coupled to the shaft. The energy that is not used for shaft work comes out in the exhaust gases, the purpose of the gas turbine determines the design so that the most desirable energy form is maximized. Gas turbines are used to power aircraft, trains, ships, electrical generators,50, Heros Engine — Apparently, Heros steam engine was taken to be no more than a toy, and thus its full potential not realized for centuries. 1000, The Trotting Horse Lamp was used by the Chinese at lantern fairs as early as the Northern Song dynasty. When the lamp is lit, the heated airflow rises and drives an impeller with horse-riding figures attached on it,1629, Jets of steam rotated an impulse turbine that then drove a working stamping mill by means of a bevel gear, developed by Giovanni Branca. 1678, Ferdinand Verbiest built a model carriage relying on a jet for power. 1791, A patent was given to John Barber, an Englishman and his invention had most of the elements present in the modern day gas turbines. The turbine was designed to power a horseless carriage,1861, British patent no.1633 was granted to Marc Antoine Francois Mennons for a Caloric engine. The patent shows that it was a gas turbine and the show it applied to a locomotive. Also named in the patent was Nicolas de Telescheff, a Russian aviation pioneer,1872, A gas turbine engine was designed by Franz Stolze, but the engine never ran under its own power. 1894, Sir Charles Parsons patented the idea of propelling a ship with a turbine, and built a demonstration vessel. This principle of propulsion is still of some use,1895, Three 4-ton 100 kW Parsons radial flow generators were installed in Cambridge Power Station, and used to power the first electric street lighting scheme in the city. 1899, Charles Gordon Curtis patented the first gas engine in the USA. 1900, Sanford Alexander Moss submitted a thesis on gas turbines, in 1903, Moss became an engineer for General Electrics Steam Turbine Department in Lynn, Massachusetts
29.
Aerodynamics
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Aerodynamics, from Greek ἀήρ aer + δυναμική, the study of the motion of air, particularly its interaction with a solid object, such as an airplane wing. Aerodynamics is a sub-field of fluid dynamics and gas dynamics, the term aerodynamics is often used synonymously with gas dynamics, the difference being that gas dynamics applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the sense in the eighteenth century. Most of the efforts in aerodynamics were directed toward achieving heavier-than-air flight. Recent work in aerodynamics has focused on issues related to flow, turbulence. Fundamental concepts of continuum, drag, and pressure gradients appear in the work of Aristotle, in 1726, Sir Isaac Newton became the first person to develop a theory of air resistance, making him one of the first aerodynamicists. In 1757, Leonhard Euler published the more general Euler equations which could be applied to both compressible and incompressible flows, the Euler equations were extended to incorporate the effects of viscosity in the first half of the 1800s, resulting in the Navier-Stokes equations. The Navier-Stokes equations are the most general governing equations of fluid flow, in 1871, Francis Herbert Wenham constructed the first wind tunnel, allowing precise measurements of aerodynamic forces. Drag theories were developed by Jean le Rond dAlembert, Gustav Kirchhoff, in 1889, Charles Renard, a French aeronautical engineer, became the first person to reasonably predict the power needed for sustained flight. Otto Lilienthal, the first person to become successful with glider flights, was also the first to propose thin, curved airfoils that would produce high lift. Building on these developments as well as carried out in their own wind tunnel. During the time of the first flights, Frederick W. Lanchester, Martin Wilhelm Kutta, Kutta and Zhukovsky went on to develop a two-dimensional wing theory. Expanding upon the work of Lanchester, Ludwig Prandtl is credited with developing the mathematics behind thin-airfoil, as aircraft speed increased, designers began to encounter challenges associated with air compressibility at speeds near or greater than the speed of sound. The differences in air flows under such conditions leds to problems in control, increased drag due to shock waves. The ratio of the speed to the speed of sound was named the Mach number after Ernst Mach who was one of the first to investigate the properties of supersonic flow. Theodore von Kármán and Hugh Latimer Dryden introduced the term transonic to describe flow speeds around Mach 1 where drag increases rapidly, by the time the sound barrier was broken, aerodynamicists understanding of the subsonic and low supersonic flow had matured. The Cold War prompted the design of an line of high performance aircraft. Understanding the motion of air around an object enables the calculation of forces, in many aerodynamics problems, the forces of interest are the fundamental forces of flight, lift, drag, thrust, and weight
30.
Fluid dynamics
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In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids. It has several subdisciplines, including aerodynamics and hydrodynamics, before the twentieth century, hydrodynamics was synonymous with fluid dynamics. This is still reflected in names of some fluid dynamics topics, like magnetohydrodynamics and hydrodynamic stability, the foundational axioms of fluid dynamics are the conservation laws, specifically, conservation of mass, conservation of linear momentum, and conservation of energy. These are based on mechanics and are modified in quantum mechanics. They are expressed using the Reynolds transport theorem, in addition to the above, fluids are assumed to obey the continuum assumption. Fluids are composed of molecules that collide with one another and solid objects, however, the continuum assumption assumes that fluids are continuous, rather than discrete. The fact that the fluid is made up of molecules is ignored. The unsimplified equations do not have a general solution, so they are primarily of use in Computational Fluid Dynamics. The equations can be simplified in a number of ways, all of which make them easier to solve, some of the simplifications allow some simple fluid dynamics problems to be solved in closed form. Three conservation laws are used to solve fluid dynamics problems, the conservation laws may be applied to a region of the flow called a control volume. A control volume is a volume in space through which fluid is assumed to flow. The integral formulations of the laws are used to describe the change of mass, momentum. Mass continuity, The rate of change of fluid mass inside a control volume must be equal to the net rate of flow into the volume. Mass flow into the system is accounted as positive, and since the vector to the surface is opposite the sense of flow into the system the term is negated. The first term on the right is the net rate at which momentum is convected into the volume, the second term on the right is the force due to pressure on the volumes surfaces. The first two terms on the right are negated since momentum entering the system is accounted as positive, the third term on the right is the net acceleration of the mass within the volume due to any body forces. Surface forces, such as forces, are represented by F surf. The following is the form of the momentum conservation equation
31.
HEPA
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Filters meeting the HEPA standard have many applications, including use in medical facilities, automobiles, aircraft and homes. The filter must satisfy certain standards of such as those set by the United States Department of Energy. To qualify as HEPA by US government standards, an air filter must remove 99. 97% of particles that have a size of 0.3 µm. HEPA was commercialized in the 1950s, and the term became a registered trademark. HEPA filters are composed of a mat of randomly arranged fibres, the fibres are typically composed of fiberglass and possess diameters between 0.5 and 2.0 micrometers. Key factors affecting its functions are fibre diameter, filter thickness, the air space between HEPA filter fibres is typically much greater than 0.3 μm. The common assumption that a HEPA filter acts like a sieve where particles smaller than the largest opening can pass through is incorrect, diffusion an enhancing mechanism that is a result of the collision with gas molecules by the smallest particles, especially those below 0. Diffusion predominates below the 0.1 μm diameter particle size, impaction and interception predominate above 0.4 μm. In between, near the most penetrating particle size 0.21 μm, both diffusion and interception are comparatively inefficient, because this is the weakest point in the filters performance, the HEPA specifications use the retention of particles near this size to classify the filter. However it is possible for smaller than the MPPS to not have filtering efficiency greater than that of the MPPS. This is due to the fact that particles can act as nucleation sites for mostly condensation. Lastly, it is important to note that HEPA filters are designed to arrest very fine particles effectively, but they do not filter out gasses and odor molecules. HEPA filters, as defined by the United States Department of Energy standard adopted by most American industries, the filters minimal resistance to airflow, or pressure drop, is usually specified around 300 pascals at its nominal flow rate. The specification usually used in the European Union is the European Norm EN1822,2009, the United States Department of Energy has specific requirements for HEPA filters in DOE regulated applications. In addition, companies have begun using a term known as True HEPA to give consumers assurance that their air filters are indeed certified to meet the HEPA standard. Products that claim to be HEPA-type, HEPA-like, HEPA-style or 99% HEPA do not satisfy these requirements, some of these sub-par quality filters may come reasonably close to HEPA filtration, while others will fall significantly short, making them truly inferior. HEPA filtration works by mechanical means unlike the Ionic and Ozone filtration which use negative ions, so, the chances of potential pulmonary side-effects like asthma and allergies is a much lower with HEPA purifiers. HEPA filters are critical in the prevention of the spread of bacterial and viral organisms and, therefore
32.
Nash Motors
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Nash Motors Company was an American automobile manufacturer based in Kenosha, Wisconsin, in the United States from 1916 to 1937. From 1937 to 1954, Nash Motors was the division of the Nash-Kelvinator Corporation. Nash production continued from 1954 to 1957 after the creation of American Motors Corporation, Nash Motors was founded in 1916 by former General Motors president Charles W. Nash who acquired the Thomas B. Jefferys best-known automobile was the Rambler whose mass production from a plant in Kenosha, the 1917 Nash Model 671 was the first vehicle produced to bear the name of the new companys founder. Nash enjoyed decades of success by focusing its efforts to build cars embodying honest worth, a price level which held out possibilities of a very wide market. The four-wheel drive Jeffery Quad truck became an important product for Nash, approximately 11,500 Quads were built between 1913 and 1919. They served to move material during World War I under severe conditions, the Quad used Meuhl differentials with half-shafts mounted above the load-bearing dead axles to drive the hubs through hub-reduction gearing. In addition, it featured four-wheel steering, the Quad achieved the reputation of being the best four-wheel drive truck produced in the country. The newly formed Nash Motors became the largest producer of four-wheel drives, by 1918, capacity constraints at Nash meant the Paige-Detroit Motor Car Company began to assemble the Nash Quad under license and Nash patents. Nash became the producer of military trucks by the end of World War I. After the war ended, surplus Quads were used as work trucks in fields such as construction. Charles Nash convinced the chief engineer of GMs Oakland Division, Finnish-born Nils Eric Wahlberg, the first Nash engine introduced in 1917 by Wahlberg had overhead valves. Wahlberg is also credited with helping to design flow-through ventilation that is used today in nearly every motor vehicle. Introduced in 1938, Nashs Weather Eye directed fresh, outside air into the cars fan-boosted, filtered ventilation system, where it was warmed, the process also helped to reduce humidity and equalize the slight pressure differential between the outside and inside of a moving vehicle. Another unique feature of Nash cars was the unequal wheel tracks, the front wheels were set slightly narrower than the rear, thus adding stability and improving cornering. Wahlberg was also a proponent of wind tunnel testing for vehicles. Nashs slogan from the late 1920s and 1930s was Give the customer more than he has paid for, innovations included a straight-eight engine with overhead valves, twin spark plugs, and nine crankshaft bearings in 1930. The 1932 Ambassador Eight had synchromesh transmissions and free wheeling, automatic centralized chassis lubrication, a rear end
33.
Weather Eye
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The Weather Eye was a trade name for a Nash Motors-designed fresh-air system for automobile passenger compartment heating, cooling, and ventilating. The Nash All-Weather Eye was the first automobile air conditioning system for the mass market, the use of the Weather Eye name for automobile passenger heating and air conditioning systems continued in American Motors vehicles. The design principles of the Nash Weather Eye system are now in use by nearly every motor vehicle, in 1938, Nash Motors developed the first automobile heater warmed by hot engine cooling water, and using fresh air. This Conditioned Air System is characterized by a cowl-mounted outside air receiver that passes fresh air through a heater core utilizing hot engine coolant for a heat source. The Nash system also pioneered the use of slight pressurization within the compartment to eliminate the infiltration of cold outside air during winter use. This was a filtered ventilation and heating for the passengers. Nash was also the first automobile to use of a disposable filter in the air-intake to clean incoming air. The Nash system was a major advancement compared to what was used up to that time, a concurrent development, the Evanair-Conditioner was offered by Hupmobile on their 1938 and 1939 model cars. In 1939, Nash added a thermostat to its system, making it the first thermostatic automobile climate control system, the Weather Eye was the first truly good heating and ventilating system. Additionally, defoggers were incorporated with the introduction of the 3900 series cars that year, the Nash HVAC system was designed by Nils Eric Wahlberg and it continues to be the basis for use in modern automobiles. Nashs Conditioned Air System heater was now marketed as the Weather Eye and consumer sales literature explained that the mechanical eye watched the weather. It was a true vapor-compression refrigeration system with a compact under the hood, combining heating, cooling, and ventilating, the new air conditioning system for the Nash cars was called the All-Weather Eye. The 1954 Nash models were the first American automobiles to have a front-end, fully integrated heating, ventilating and this was the first mass market system with controls on the dash and an electrically-engaged clutch. This first true refrigerated air conditioner system for automobiles was also compact, with a single thermostatic control, the Nash passenger compartment air cooling option was described as a good and remarkably inexpensive system. Entirely incorporated within the bay, the combined heating and cooling system had cold air for passengers enter through dash-mounted vents. Nashs exclusive remarkable advance was not only the sophisticated unified system, the optional air conditioning system offered by Oldsmobile cost $199 more and it weighed twice as much as the integrated Nash unit that added only 133 pounds. A feature was the only setting on the A/C thermostat control. In humid environments, the evaporator will freeze up from the accumulating condensation if the compressor operates constantly, other temperature settings cycle the compressor to prevent this problem
34.
Allergen
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An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. In technical terms, an allergen is a capable of stimulating a type-I hypersensitivity reaction in atopic individuals through Immunoglobulin E responses. Most humans mount significant Immunoglobulin E responses only as a defense against parasitic infections, however, some individuals may respond to many common environmental antigens. This hereditary predisposition is called atopy, in atopic individuals, non-parasitic antigens stimulate inappropriate IgE production, leading to type I hypersensitivity. Sensitivities vary widely from one person to another, a very broad range of substances can be allergens to sensitive individuals. Allergens can be found in a variety of sources, such as dust mite excretion, pollen, Food allergies are not as common as food sensitivity, but some foods such as peanuts, nuts, seafood and shellfish are the cause of serious allergies in many people. Officially, the United States Food and Drug Administration does recognize eight foods as being common for reactions in a large segment of the sensitive population. These include peanuts, tree nuts, eggs, milk, shellfish, fish, wheat and their derivatives, see the FDA website for complete details. Canada recognizes all eight of the allergens recognized by the US, and also recognizes sesame seeds, the European Union additionally recognizes celery. Various trees and wood products such as paper, cardboard, MDF etc. can also cause mild to severe allergy symptoms through touch or inhalation of sawdust such as asthma, other common causes of serious allergy are wasp, fire ant and bee stings, penicillin, and latex. An extremely serious form of a reaction is called anaphylaxis. This depends on the kind of tree or grass, for instance, some trees such as oak, elm, and maple pollinate in the spring, while grasses such as Bermuda, timothy and orchard pollinate in the summer. Grass allergy is generally linked to hay fever because their symptoms, symptoms include rhinitis, which causes sneezing and a runny nose, as well as allergic conjunctivitis, which includes watering and itchy eyes. Also an initial tickle on the roof of the mouth or in the back of the throat may be experienced, also, depending on the season, the symptoms may be more severe and people may experience coughing, wheezing, and irritability. A few people even become depressed, lose their appetite, or have problems sleeping, moreover, since the sinuses may also become congested, some people experience headaches. The immune system also has influence on seasonal allergies, since it reacts differently to diverse allergens like pollen. When an allergen enters the body of an individual that is predisposed to allergies, it triggers an immune reaction and these allergen antibodies migrate to mast cells lining the nose, eyes and lungs. Some symptoms that differentiate allergies from a cold include, No fever, mucous secretions are runny and clear
35.
Heater core
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A heater core is a radiator-like device used in heating the cabin of a vehicle. Hot coolant from the engine is passed through a winding tube of the core. Fins attached to the core tubes serve to increase surface for heat transfer to air that is forced past them, by a fan, some of that water can be diverted through the heater core to give some engine heat to the cabin. A heater core is a radiator, located under the dashboard of the vehicle. Hot coolant passing through the heater core gives off heat before returning to the cooling circuit. The fan for the ventilation system forces air through the heater core to transfer heat from the coolant to the cabin air. Once the engine has warmed up, the coolant is kept at a more or less constant temperature by the thermostat, the temperature of the air entering the vehicles interior can be controlled by using a valve limiting the amount of coolant that goes through the heater core. Another method is blocking off the core with a door, directing part of the incoming air around the heater core completely. Some cars use a combination of these systems, simpler systems allow the driver to control the valve or door directly. More complicated systems use electronics to control the valve or doors, cars with dual climate function may use a heater core split in two, where different amounts of coolant flow through the heater core on either side to obtain the desired heating. In a car equipped with air conditioning, outside air is first forced through the air conditioners evaporator coil and this can be thought of as a heater core filled with very cold gas, which cools rather than heats the incoming air. In order to obtain the desired temperature incoming air may first be cooled by the air conditioning and this can result in increased air comfort levels inside the vehicle. Because the heater core cools the heated coolant from the engine it can act as the radiator of the engine, if the radiator is working improperly, the operator may turn the heat on in the passenger cabin, resulting in cooling the engine coolant and then cooling the engine. This idea only works to a degree, as the heater core is not large enough nor does it have enough cold air going though it to cool large amounts of coolant significantly. The heater core is made up of small piping that has numerous bends, clogging of the piping may occur if the coolant system is not flushed or if the coolant is not changed regularly. If clogging occurs the core will not work properly. If coolant flow is restricted, heating capacity will be reduced or even lost altogether if the core becomes blocked. Control valves may also clog or get stuck, another possible problem is a leak in one of the connections to the heater core
36.
Evaporator
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An evaporator is a device used to turn the liquid form of a chemical into its gaseous form. The liquid is evaporated, or vaporized, into a gas, an evaporator is used in an air-conditioning system to allow a compressed cooling chemical, such as R-22 or R-410A, to evaporate from liquid to gas while absorbing heat in the process. It can also be used to water or other liquids from mixtures. The process of evaporation is used to concentrate foods and chemicals as well as salvage solvents. In the concentration process, the goal of evaporation is to vaporize most of the water from a solution which contains the desired product. In the case of desalination of sea water or in Zero Liquid Discharge plants, one of the most important applications of evaporation is in the food and beverage industry. Foods or beverages that need to last for a amount of time or need to have certain consistency, like coffee. In the pharmaceutical industry, the process is used to eliminate excess moisture, providing an easily handled product. Preservation of long-term activity or stabilization of enzymes in laboratories are greatly assisted by the evaporation process, another example of evaporation is in the recovery of sodium hydroxide in kraft pulping. Cutting down waste-handling cost is another reason for large companies to use evaporation applications. Legally, all producers of waste must dispose of waste using methods compatible with environmental guidelines, by removing moisture through vaporization, industry can greatly reduce the amount of waste product that must be processed. Water can be removed from solutions in other than evaporation, including membrane processes, liquid-liquid extractions, crystallization. Evaporation can be distinguished from some other drying methods in that the product of evaporation is a concentrated liquid. It is also simple to use and understand since it has been widely used on a large scale. In order to concentrate a product by water removal, a phase is used which allows for easy transport of the solvent rather than the solute. Water vapor is used as the phase when concentrating non-volatile components, such as proteins. Heat is added to the solution, and part of the solvent is converted into vapor, heat is the main tool in evaporation, and the process occurs more readily at high temperature and low pressures. Heat is needed to provide energy for the molecules of the solvent to leave the solution
37.
Automobile air conditioning
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Automobile air conditioning systems use air conditioning to cool the air in a vehicle. A company in New York City in the United States first offered installation of air conditioning for cars in 1933, most of their customers operated limousines and luxury cars. In 1939, Packard became the first automobile manufacturer to offer an air conditioning unit in its cars and these were manufactured by Bishop and Babcock Co, of Cleveland, Ohio. The Bishop and Babcock Weather Conditioner also incorporated a heater, cars ordered with the new Weather Conditioner were shipped from Packards East Grand Boulevard facility to the B&B factory where the conversion was performed. Once complete, the car was shipped to a local dealer where the customer would take delivery, Packard fully warranted and supported this conversion, and marketed it well. However, it was not commercially successful for a number of reasons, The main evaporator and it was superseded by more efficient systems in the post-war years. It had no temperature thermostat or shut-off mechanism other than switching the blower off, the several feet of plumbing going back and forth between the engine compartment and trunk proved unreliable in service. The price, at US $274, was unaffordable to most people in post-depression/pre-war America, the option was discontinued after 1941. Walter Chrysler had seen to the invention of Airtemp air conditioning in the 1930s for the Chrysler Building, and had offered it on cars in 1941-42, the Airtemp was more advanced than rival automobile air conditioners by 1953. It was operated by a switch on the dashboard marked with low, medium. As the highest capacity unit available at time, the system was capable of quickly cooling the passenger compartment and also reducing humidity, dust, pollen. The system drew in more air than contemporary systems, thus. Cadillac, Buick, and Oldsmobile added air conditioning as an option on some of their models in the 1953 model year, all of these Frigidaire systems used separate engine and trunk mounted components. In 1954, the Nash Ambassador was the first American automobile to have a front-end, fully integrated heating, ventilating and this was the first mass market system with controls on the dash and an electric clutch. This system was also compact and serviceable with all of its components installed under the hood or in the cowl area, combining heating, cooling, and ventilating, the new air conditioning system for the Nash cars was called the All-Weather Eye. This followed the name of Weather Eye for Nashs fresh-air automotive heating and ventilating system that was first used in 1938. With a single control, the Nash passenger compartment air cooling option was a good. The system had cold air for passengers enter through dash-mounted vents, Nashs exclusive remarkable advance was not only the sophisticated unified system, but also its $345 price that beat all other systems
38.
Fuel injection
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Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of an injector. All diesel engines use fuel injection by design, petrol engines can use gasoline direct injection, where the fuel is directly delivered into the combustion chamber, or indirect injection where the fuel is mixed with air before the intake stroke. On petrol engines, fuel injection replaced carburetors from the 1980s onward, the functional objectives for fuel injection systems can vary. All share the task of supplying fuel to the combustion process. Carburetors have the potential to atomize fuel better, Fuel injection also dispenses with the need for a separate mechanical choke, which on carburetor-equipped vehicles must be adjusted as the engine warms up to normal temperature. Furthermore, on spark ignition engines, fuel injection has the advantage of being able to facilitate stratified combustion which have not been possible with carburetors, Fuel injection generally increases engine fuel efficiency. With the improved cylinder-to-cylinder fuel distribution of multi-point fuel injection, less fuel is needed for the power output. Exhaust emissions are cleaner because the precise and accurate fuel metering reduces the concentration of toxic combustion byproducts leaving the engine. The more consistent and predictable composition of the exhaust makes emissions control devices such as catalytic converters more effective, herbert Akroyd Stuart developed the first device with a design similar to modern fuel injection, using a jerk pump to meter out fuel oil at high pressure to an injector. This system was used on the engine and was adapted and improved by Bosch. Fuel injection was in commercial use in diesel engines by the mid-1920s. Another early use of direct injection was on the Hesselman engine invented by Swedish engineer Jonas Hesselman in 1925. Hesselman engines use the ultra lean-burn principle, fuel is injected toward the end of the compression stroke and they are often started on gasoline and then switched to diesel or kerosene. Direct fuel injection was used in notable World War II aero-engines such as the Junkers Jumo 210, the Daimler-Benz DB601, the BMW801, German direct injection petrol engines used injection systems developed by Bosch from their diesel injection systems. Later versions of the Rolls-Royce Merlin and Wright R-3350 used single point fuel injection, due to the wartime relationship between Germany and Japan, Mitsubishi also had two radial aircraft engines utilizing fuel injection, the Mitsubishi Kinsei and the Mitsubishi Kasei. Alfa Romeo tested one of the first electronic systems in Alfa Romeo 6C2500 with Ala spessa body in 1940 Mille Miglia. The engine had six electrically operated injectors and were fed by a semi-high-pressure circulating fuel pump system, all diesel engines have fuel injected into the combustion chamber. The invention of mechanical injection for gasoline-fueled aviation engines was by the French inventor of the V8 engine configuration, Leon Levavasseur in 1902, the first post-World War I example of direct gasoline injection was on the Hesselman engine invented by Swedish engineer Jonas Hesselman in 1925
39.
Throttle
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A throttle is the mechanism by which fluid flow is managed by constriction or obstruction. An engines power can be increased or decreased by the restriction of inlet gases, the term throttle has come to refer, informally and incorrectly, to any mechanism by which the power or speed of an engine is regulated. What is often termed a throttle is more correctly called a thrust lever, for a steam engine, the steam valve that sets the engine speed/power is often known as a regulator. A diesel engine does not have a throttle except there is a valve on the newer diesel engines which is generally referred to as air management valves. Air management valves can be with or without integrated control electronics, the throttle is typically a butterfly valve. In a fuel-injected engine, the valve is placed on the entrance of the intake manifold. In a carbureted engine, it is found in the carburetor, when a throttle is wide open, the intake manifold is usually at ambient atmospheric pressure. When the throttle is closed, a manifold vacuum develops as the intake drops below ambient pressure. Usually, the valve is controlled with a throttle pedal or lever via a direct mechanical linkage. In vehicles with electronic control, the manual throttle control sends a signal to the Engine Control Unit. This means that the operator does not have control over the throttle valve. In a reciprocating-engine aircraft, the control is usually a hand-operated lever or knob. It controls the power output, which may or may not reflect in a change of RPM. The power output of an engine is controlled by regulating the quantity of fuel that is injected into the cylinder. Because the engines do not need to control air volumes, they lack a butterfly valve in the intake tract. In fuel injected engines, the body is the part of the air intake system that controls the amount of air flowing into the engine. The throttle body is located between the air filter box and the intake manifold, and it is usually attached to, or near. The largest piece inside the body is the throttle plate
40.
Carburetor
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A carburetor, or carburettor, or carburator, or carburetter is a device that blends air and fuel for an internal combustion engine in the proper ratio for combustion. It is sometimes shortened to carb in North America or carby in Australia. To carburate or carburet is to blend the air and fuel or to equip with a carburetor for that purpose, carburetors have largely been supplanted in the automotive and, to a lesser extent, aviation industries by fuel injection. They are still common on engines for lawn mowers, rototillers. The word carburetor comes from the French carbure meaning carbide, carburer means to combine with carbon. In fuel chemistry, the term has the specific meaning of increasing the carbon content of a fluid by mixing it with a volatile hydrocarbon. The first carburetor was invented by Samuel Morey in 1826, a carburetor was invented by an Italian, Luigi De Cristoforis, in 1876. Another carburetor was developed by Enrico Bernardi at the University of Padua in 1882, for his Motrice Pia, a carburetor was among the early patents by Karl Benz as he developed internal combustion engines and their components. Early carburetors were the surface type, in which air is charged with fuel by being passed over the surface of gasoline. In 1885, Wilhelm Maybach and Gottlieb Daimler developed a float carburetor for their engine based on the atomizer nozzle, hungarian engineers János Csonka and Donát Bánki patented a carburetor for a stationary engine in 1893. Frederick William Lanchester of Birmingham, England, experimented with the wick carburetor in cars, in 1896, Frederick and his brother built the first gasoline-driven car in England, a single cylinder 5 hp internal combustion engine with chain drive. Unhappy with the performance and power, they re-built the engine the next year into a horizontally opposed version using his new wick carburetor design. Carburetors were the method of fuel delivery for most US-made gasoline-fueled engines up until the late 1980s. 1991, Jeep Grand Wagoneer with the AMC360 cu in V8 engine, low-cost commercial vans and 4WDs in Australia continued with carburetors even into the 2000s, the last being the Mitsubishi Express van in 2003. Elsewhere, certain Lada cars used carburetors until 2006, many motorcycles still use carburetors for simplicitys sake, since a carburetor does not require an electrical system to function. EEC legislation required all vehicles sold and produced in countries to have a catalytic converter after December 1992. This legislation had been in the pipeline for some time, with cars becoming available with catalytic converters or fuel injection from around 1990. Fords first fuel-injected car was the Ford Capri RS2600 in 1970, general Motors launched its first fuel-injected car around the same time, when began to introduce fuel-injected engines to its Vauxhall Cavalier/Opel Ascona range
41.
Car
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A car is a wheeled, self-powered motor vehicle used for transportation and a product of the automotive industry. The year 1886 is regarded as the year of the modern car. In that year, German inventor Karl Benz built the Benz Patent-Motorwagen, cars did not become widely available until the early 20th century. One of the first cars that was accessible to the masses was the 1908 Model T, an American car manufactured by the Ford Motor Company. Cars were rapidly adopted in the United States of America, where they replaced animal-drawn carriages and carts, cars are equipped with controls used for driving, parking, passenger comfort and safety, and controlling a variety of lights. Over the decades, additional features and controls have been added to vehicles, examples include rear reversing cameras, air conditioning, navigation systems, and in car entertainment. Most cars in use in the 2010s are propelled by a combustion engine. Both fuels cause air pollution and are blamed for contributing to climate change. Vehicles using alternative fuels such as ethanol flexible-fuel vehicles and natural gas vehicles are also gaining popularity in some countries, electric cars, which were invented early in the history of the car, began to become commercially available in 2008. There are costs and benefits to car use, the costs of car usage include the cost of, acquiring the vehicle, interest payments, repairs and auto maintenance, fuel, depreciation, driving time, parking fees, taxes, and insurance. The costs to society of car use include, maintaining roads, land use, road congestion, air pollution, public health, health care, road traffic accidents are the largest cause of injury-related deaths worldwide. The benefits may include transportation, mobility, independence. The ability for humans to move flexibly from place to place has far-reaching implications for the nature of societies and it was estimated in 2010 that the number of cars had risen to over 1 billion vehicles, up from the 500 million of 1986. The numbers are increasing rapidly, especially in China, India, the word car is believed to originate from the Latin word carrus or carrum, or the Middle English word carre. In turn, these originated from the Gaulish word karros, the Gaulish language was a branch of the Brythoic language which also used the word Karr, the Brythonig language evolved into Welsh where Car llusg and car rhyfel still survive. It originally referred to any wheeled vehicle, such as a cart, carriage. Motor car is attested from 1895, and is the formal name for cars in British English. Autocar is a variant that is attested from 1895
42.
Paper
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Paper is a thin material produced by pressing together moist fibres of cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. It is a material with many uses, including writing, printing, packaging, cleaning. The modern pulp and paper industry is global, with China leading its production, the oldest known archaeological fragments of the immediate precursor to modern paper, date to the 2nd century BC in China. The pulp papermaking process is ascribed to Cai Lun, a 2nd-century AD Han court eunuch, with paper as an effective substitute for silk in many applications, China could export silk in greater quantity, contributing to a Golden Age. Because of papers introduction to the West through the city of Baghdad, in the 19th century, industrial manufacture greatly lowered its cost, enabling mass exchange of information and contributing to significant cultural shifts. In 1844, the Canadian inventor Charles Fenerty and the German F. G. Keller independently developed processes for pulping wood fibres, before the industrialisation of the paper production the most common fibre source was recycled fibres from used textiles, called rags. The rags were from hemp, linen and cotton, a process for removing printing inks from recycled paper was invented by German jurist Justus Claproth in 1774. Today this method is called deinking and it was not until the introduction of wood pulp in 1843 that paper production was not dependent on recycled materials from ragpickers. The word paper is etymologically derived from Latin papyrus, which comes from the Greek πάπυρος, although the word paper is etymologically derived from papyrus, the two are produced very differently and the development of the first is distinct from the development of the second. Papyrus is a lamination of natural plant fibres, while paper is manufactured from fibres whose properties have changed by maceration. To make pulp from wood, a chemical pulping process separates lignin from cellulose fibres and this is accomplished by dissolving lignin in a cooking liquor, so that it may be washed from the cellulose, this preserves the length of the cellulose fibres. Paper made from chemical pulps are also known as wood-free papers–not to be confused with paper, this is because they do not contain lignin. The pulp can also be bleached to produce paper, but this consumes 5% of the fibres, chemical pulping processes are not used to make paper made from cotton. There are three main chemical pulping processes, the process dates back to the 1840s and it was the dominant method extent before the second world war. Most pulping operations using the process are net contributors to the electricity grid or use the electricity to run an adjacent paper mill. Another advantage is that this process recovers and reuses all inorganic chemical reagents, soda pulping is another specialty process used to pulp straws, bagasse and hardwoods with high silicate content. There are two major mechanical pulps, thermomechanical pulp and groundwood pulp, in the TMP process, wood is chipped and then fed into steam heated refiners, where the chips are squeezed and converted to fibres between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones to be made into fibres
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Car tuning
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Car tuning is modification of the performance or appearance of a vehicle. For actual tuning in the sense of automobiles or vehicles, see engine tuning, most vehicles leave the factory set up for an average drivers expectations and conditions. Tuning, on the hand, has become a way to personalize the characteristics of a vehicle to the owners preference. Cars may be altered to better fuel economy, produce more power. Car tuning is related to racing, although most performance cars never compete. Tuned cars are built for the pleasure of owning and driving, exterior modifications include changing the aerodynamic characteristics of the vehicle via side skirts, front and rear bumpers, spoilers, splitters, air vents and light weight wheels. Cars have always been subject to after-market modification, the golden age of car tuning was the decades between World War II and the beginning of air pollution restrictions. Both moderate and radical modification have been commemorated in the popular songs Hot Rod Race, the names of Abarth and Cooper appear on models styled after the cars they modified. Cosworth went, with support from Ford, from modifying English Ford Flathead engines for Lotus Sevens to dominating Formula One, in the 1970s and 80s, many Japanese performance cars were never exported outside the Japanese domestic market. In the late 1980s and early 1990s, grey imports of Japanese performance cars, such as the Nissan Skyline, began to be imported into Western Europe. Because of their weight and the increasing availability of low-cost tuning equipment, economy. As professional sporting and racing with such vehicles increased, so did recreational use of these vehicles, drivers with little or no automotive, mechanical, or racing experience would modify their vehicles to emulate the more impressive versions of racing vehicles, with mixed results. A stock audio system is one specified by the manufacturer when the vehicle was built in the factory, a custom audio installation can involve anything from the upgrade of the radio to a full-blown customization based around the audio equipment. Events are held where entrants compete for the loudest, highest quality reception or most innovative sound systems, some common modifications include higher quality speakers and sub woofers, amps, a better wiring system, etc. All cars competing in each class must adhere to a set of regulations. As in some racing events, like NASCAR and NHRA. In such cases the interior is stripped, and the weight is achieved by adding ballast that allows precise control over weight distribution. Along with weight requirements, safety requirements are present, roll cages, fire extinguishers, reinforced bucket seats, seat harnesses, and the like are some of the required safety modifications
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Polyurethane foam
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Over three quarters of the global consumption of polyurethane products is in the form of foams, with flexible and rigid types being roughly equal in market size. Its use in garments is growing, for example, in lining the cups of brassieres, polyurethane is also used for moldings which include door frames, columns, balusters, window headers, pediments, medallions and rosettes. Polyurethane formulations cover a wide range of stiffness, hardness. The foam is then cut to the shape and size for use in a variety of furniture. Applications for flexible polyurethane foam include upholstered furniture cushions, automotive seat cushions and interior trim, carpet cushion, flexible polyurethane foam is a recyclable product. Flexible and semi-flexible polyurethane foams are used extensively for interior components of automobiles, in seats, headrests, armrests, roof liners, dashboards, polyurethanes are used to make automobile seats in a remarkable manner. The seat manufacturer has a mold for each seat model, the mold is a closeable clamshell sort of structure that will allow quick casting of the seat cushion, so-called molded flexible foam, which is then upholstered after removal from the mold. It is possible to combine these two steps, so-called in-situ, foam-in-fabric or direct moulding, a complete, fully assembled seat cover is placed in the mold and held in place by vacuum drawn through small holes in the mold. Sometimes a thin plastic film backing on the fabric is used to help the vacuum work more effectively. The metal seat frame is placed into the mold and the mold closed, at this point the mold contains what could be visualized as a hollow seat, a seat fabric held in the correct position by the vacuum and containing a space with the metal frame in place. Polyurethane chemicals are injected by a head into the mold cavity. Then the mold is held at a preset reaction temperature until the mixture has foamed, filled the mold. The time required is two to three minutes, depending on the size of the seat and the formulation and operating conditions. Then the mold is usually opened slightly for a minute or two for a cure time, before the fully upholstered seat is removed. The walls and ceiling of the futuristic Xanadu House were built out of polyurethane foam, domed ceilings and other odd shapes are easier to make with foam than with wood. Foam was used to build oddly shaped buildings, statues, speciality rigid foam manufactures sell foam that replace wood in carved sign and 3D-topography industries. PU foam is used as a thermal insulator in many houses. Polyurethane resin is used as a flooring material
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