The rise of the domestic four-wheel drive sedan market

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    Talk about a car-driven approach, we have in mind are basically two drives, such as the Jetta, Passat, Fukang and other precursor and Cadillac CTS, crown, rear-wheel drive BMW and so on. In actual fact, not all cars are two-drive, four-wheel drive SUV is not a patent. Some good cars there is increasing is equipped with four-wheel drive, it can bring more than the average car safety and driving pleasure.

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    As we all know, ordinary two-drive cars have the engine all of the power output to the two front or two rear wheels, while four-wheel drive sedan is a four wheels simultaneously have been the driving force, as compared with the two drive, four-wheel drive performance The office is more commendable. Generally speaking, in winter snow and ice Road, the summer wet roads, high-speed, high-speed change when the line of cases, the wheel adhesion is weak, this time the wheels will slip, steering can not quite place, is related to the danger of not the key. This case, the precursor of vehicles prone to understeer, that is often said, "Tuitou", and then drive vehicles, turning often result in a "Drift." sdio wireless lan

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    Because it is the power to effectively pass through the four wheels to the ground, four-wheel drive cars but can effectively avoid these problems, better handling stability and security. On the other hand, four-wheel drive sedan also has a strong drive through the merits and good, you can climb the rock in the rugged trails, you can look through the hills to leave the highway, this is a two-drive cars driving pleasure unparalleled.



The domestic market, the existing four-wheel drive cars are mainly Audi, VOLVO, Fuji Heavy Industries, Subaru's part of the model. Audi's quattro all-wheel-drive sedan is characterized by a normal road driving in a good, 75% of the power output to the front wheels, rear wheel only assigned to 25%; when the road adhesion conditions change, the differential automatically adjust power output ratio, the rear wheels can be assigned up to 75% of the power, can effectively prevent wheel slip.



VOLVO AWD car with a set of electronic control gear on Demand (AOD), usually the main or front-wheel drive, four wheel speed when the detected inconsistent, AOD can be extremely fast transfer speeds increase or decrease in number according to driving conditions change the momentum of the momentum transfer to the rear wheels up to 65%. Subaru is about 30 million to 400 thousand yuan for four-wheel drive cars where representatives from its four-wheel drive technology is different from other front or rear as well as the AWD driven car, car in motion at any time, four wheels independently driven, even more outstanding and security, and won the pursuit of dynamic play car enthusiasts favor.



From Audi, VOLVO, and several four-wheel drive Subaru cars that run, even though they used four-wheel drive system structure are quite different, but there was a common feature is the ability to take the initiative to intelligent distribution according to different road conditions at all wheels front and rear axle driving force, thereby driving stability and road handling to achieve the best.



November 21 unveiled Chery Tiggo NCV (New Concept Vehicle) "a new concept car." Also used an intelligent four-wheel drive system, Borg Warner (BorgWarner) developed. The system can always collect the road information, road traffic is good, a two-drive model of the road, both energy-saving, but also ensures the stability of driving; when the system collected information on specific road conditions when the switch in time four-wheel drive vehicle model, and front and rear torque distribution of the bridge to the best to play well through sex. All of the two-drive / four-wheel drive switch is done automatically through the computer, which is Audi, VOLVO-wheel-drive cars, works basically the same.



    Maximum of two different one Tiggo NCV is allocated to power the rear axle can be from 0% to 100%, that is, when the front wheel skid completely full output power to the rear wheels; the other is the "active", such as when you pass a small parking of torque or zero torque, parking easier, when the received signal ABS working, intelligent AWD system immediately stop working to ensure that ABS system is fully functioning.



Judging from the current overall market perspective, four-wheel drive cars that are equipped with two-drive sedan driving comfort and a good four-wheel SUV through sex, but also to abandon the traditional big SUV driving resistance, manipulation is not flexible enough, the shortcomings of the high fuel consumption. With the gradual consumer attitudes, consumer groups, grown up and a number of buyers seeking dynamic and personality driven-wheel-drive cars there sales growth; the other hand, the rise of the domestic four-wheel drive sedan market will also give consumers more more surprises.

Changan Town, Dongguan, increased measures to provide incentives for better hardware mold Enterprise

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   Changan Town, Dongguan has promulgated the "Interim Measures for domestic investment incentives" (hereinafter referred to as "measures"), die enterprises to bring in a maximum will be awarded 500,000 yuan. For the mechanical metal mold enterprise, will depend on the specific circumstances the appropriate incentives to improve the introduction of those standards, in which bonuses were awarded for community collective 50%, 50% of the awarded communities, private office, the introduction of a single project the maximum award amount of 500,000 yuan.

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Chang'an Town, "domestic investment incentives Interim Measures," provides a starting point is the reward: the introduction of domestic-funded enterprises two years, the actual investment in fixed assets reached 1,000 million yuan, but the mechanical metal mold can be raised to two years, companies of 800 million yuan. For two years, the actual investment in fixed assets in 1000 yuan business, in principle, be the introduction of those incentives, unless the business year the total reached 100 million yuan tax. forging machines

cold roll forming machine

Chang-an town government will be introduced within the community-funded project, according to its visibility, size, technology, content and other factors contribute to local taxes, and business fixed investment in two years, the actual value of a one-time grant award, awards do not exceed the maximum amount of fixed assets value of 10%.



For the mechanical metal mold enterprise, will depend on the specific circumstances the appropriate incentives to improve the introduction of those standards, in which bonuses were awarded for community collective 50%, 50% of the awarded communities, private office, the introduction of a single project the maximum award amount of 500,000 yuan.



In addition, the town will be the introduction of new large-scale domestic project implementation supporting facilities. Communities introduced domestic-funded enterprises, if a government-owned major support for the Chang-an town businesses, the government will large-scale projects in the land, electricity, business people and households, enterprise backbone enroll their children at public schools town of indicators, corporate finance, etc., according to their actual situation and the priority given to key support.

Chinese steel flange of the Township

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upholstered arm chair chrome dining chairs

   Sui town a total of 14 enterprises casting flange, output accounted for half of the country, the product monopolize the domestic market and exported to the Middle East, Southeast Asia. Sui town and therefore known as "China's steel flange of the town." dining chair seat covers

Mining machinery manufacturing

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Mining machinery in the economic construction, scientific and technological progress and social development occupies an important position and role of the pillar industries belonging to the national economy. Mining machinery manufacturing industry is the establishment of an independent state based industrial system, but also to measure an important indicator of national industrial strength. According to the key support for energy, transportation and raw materials and other basic industrial development, industrial policy, mining machinery, as these basic industries, pillar of national priorities should be given priority support to further develop and improve, for coal, metal and nonmetal mines Development to provide more advanced level of international quality, high efficiency crusher, milling machine, sand making equipment, to meet the economic development for energy and raw materials needs.



The development of a mining machinery of the technological progress of mankind, modern science and technology and is closely related to the overall industrial level, particularly with the mechanical engineering sciences and closely linked to the development of mining disciplines. Forefront of modern science and technology has obvious time-domain, area, and dynamic properties. Information science, materials science, life science, nano-science, management science and manufacturing science are changing the 21st century, mainstream science, the resulting high-tech and the industry will change the world. at pl120

extension cord reels

The intersection between the integration of different scientific, will generate new scientific focus, economic development and social progress of the mining machinery to generate new demands and expectations. Mechanical Engineering, the general trend of scientific development will be digital, intelligent, precision, miniaturization, life-oriented, and ecological. Mining machinery, as a branch of mechanical engineering disciplines, but also follow this general trend. At the same time, combining the characteristics of mining industry and its development trend is the digital, intelligent, ecological and amenity-oriented. Mining machinery manufacturing industry should continue to integrate into the human outstanding achievements in various fields, facing the major national economic development needs of the scientific outlook on development as guidance, to achieve sustainable development. computer cable organizer



Competition in the market-driven



The overall level of China's mining machinery, compared with the international advanced level there are still gaps. In the run mining machinery manufacturing power journey, opportunities and challenges coexist. Product design is the soul of the manufacturing industry, product structure, function, quality, cost, delivery time and manufacturability, maintainability, and disposal post-processing, and human, machine and environment relationship, in principle, are in the product design stage decision. Product innovation and design capability has become a deciding the status of global competition in the primary factor.



Mining Machinery is a high technological content and integration of equipment, development of new equipment constantly results in all areas of human integration in, along with materials science, manufacturing technology, information technology, computer technology, each product has a into new technologies, parts and components updates become shorter and shorter, faster and faster replacement of new equipment, in particular the development of large-scale mining machinery, non-mature experience to draw on, but the design does not allow any mistakes and must therefore be With the integration of multi-disciplinary technologies to improve design efficiency and design quality, enhance corporate capability of independent innovation and market competitiveness. Mining machinery and computer technology, network technology, based on the formation of an integrated digital technology trends.



The needs of economic construction



Along with social progress and national economic development, human resources and energy demand is growing, while China is a relatively resource-poor countries. As resource development, mining depth increased gradually extending to the ocean from land, resources, deteriorating mining conditions and safe exploitation of the situation is becoming increasingly serious; China's coal mining has reached the depth of 1000m, the concentration of metal ores 1380m, deposit, mining depth increased , groundwater, gas, highland stress, geological structure to enable the exploitation of resources greatly increased the difficulty.



No underground mining is the automated face a dangerous environment or the direction of development of mining, but also protect the safety of mining face an effective way. Comprehensive use of mining science, automation technology, communication technology, computer science and technology, automated unmanned face exploitation in basic theoretical research and development of new technologies, new equipment, so that mining machinery will be towards robots and intelligent direction.



With a variety of undersea deposits of strategic metals and mineral resources, to achieve efficient and safe marine mineral resources exploitation, in order to protect the country's maritime rights and interests and provide technical support for national economic development, social and sustainable development, protection. Achieve seabed mining, the need to develop deep submarine-controlled unmanned submersible, unmanned non-self-submersible cable mining machinery and equipment such as intelligent.



The need for the harmonious development of the natural environment



China's "Eleventh Five-Year" Plan pointed out that to build a resource-saving and environment-friendly society, focusing on the development of circular economy has insisted on developing equal emphasis on conservation, conservation priority, according to reduction, re-use, resource-oriented principle, resource extraction, production of consumption, waste generation, consumption and other sectors, and gradually establish the resources of society as a whole recycling system; to save energy, water conservation, saving land, saving materials and strengthening the comprehensive utilization of resources to strengthen the promotion of conservation policies. Machinery manufacturing industry from the simple pursuit of scale and efficiency of the model to build 4R cycle of economic direction.



For the natural environment and achieve the harmonious development of the required mining machinery "eco", with the help of advanced technologies on manufacturing model, manufacturing resources, manufacturing, process manufacturing organizations continually innovate to make our products throughout the life cycle does not produce environmental pollution or environmental pollution minimize the maximum utilization of resources, the lowest energy consumption, and ultimately corporate co-ordination of economic and social benefits. Efficient, zero emission fuel cell mining machinery has good development prospects.



Geothermal energy as a green, renewable resources, has been identified as countries around the world to maintain social sustainable development, new energy, the geothermal resource-rich developed countries have been a better use of resources and the development of crustal heat treatment of solid waste resources for the Mining Machinery expanded its service areas. Mining machinery in the computer technology, network technology, multi-disciplinary integrated support for economic development, driven by demand in the market, in the harmonious development of mankind and nature, the mining machinery has been upgraded to digital, intelligent, ecological and pleasant-oriented direction.



Therefore, the state-owned mining machinery plant in Henan With this favorable opportunity, and vigorously develop new products and equipment, such as coarse broken jaw-breaking series of mobile crushing machines, broken the back-breaking series of mobile crushing machine, crushing cone-breaking series of mobile crushing machines, MTW European edition trapezoidal milling machine, large vertical milling machine, CS cone crusher, the EU version of JC series of jaw crusher (jaw crusher), VSI New Type Sand (Sand Making Machine), 5X Series New Sand (system of sand machine), large-scale hydraulic milling machine, and so a number of high gold content of the mining machinery and equipment, specifically for the current needs of the natural environment and national construction standards used in aggregate research and development, and is widely used in key national highways, railway engineering projects, including water conservancy, hydropower and other industries strong advantage, especially the European version of trapezoidal vertical milling machine and a large flour mill with a typical representative of the two mill products, popular with all major cement welcome and favor, is the only energy-saving and environmentally friendly cement by the best equipment.

Coffea

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Botany

Coffea canephora

When grown in the tropics, coffee is a vigorous bush or small tree which usually grow to a height of 33.5 m (1012 feet). Most commonly cultivated coffee species grow best at high elevations. Although they are hardy and capable of withstanding severe pruning, they are nevertheless not very tolerant of sub-freezing temperatures, and so cannot be grown in temperate climate zones. To produce a maximum yield of coffee berries/cherries (8001400 kg per hectare), the plants need substantial amounts of water and fertilizer. Since they grow best in alkaline soils, calcium carbonate and other lime minerals are sometimes used to reduce acidity in the soil, which can occur due to run off of minerals from the soil in mountainous areas. The caffeine in coffee "beans" is a natural defense: a toxic substance which repels many creatures that would otherwise eat the seeds - as with the nicotine in tobacco leaves. ice maker industrial

Coffea berries, Bali sugar cane juicer

There are several species of Coffee that may be grown for the beans, but Coffea arabica is considered by many to have the best overall flavor and quality.[citation needed] The other species (especially Coffea canephora (var. robusta)) are usually grown on land unsuitable for Coffea arabica. The tree produces red or purple fruits (drupes), which contain two seeds (the "coffee beans", which despite their name are not true beans, which are the seeds of the legume family). In about 5-10% of any crop of coffee cherries, the cherry will contain only a single bean, rather than the two usually found. This is called a 'peaberry', which is smaller and rounder than a normal coffee bean. It is often removed from the yield and either sold separately, (as in New Guinea Peaberry) or discarded. home meat slicer

The tree of Coffea arabica will grow fruits after 3  5 years and will produce for about 50  60 years (although up to 100 years is possible). The blossom of the coffee tree is similar to jasmine in color and smell. The fruit takes about nine months to ripen. Worldwide, an estimated 15 billion coffee trees are grown on 100,000 km2 (39,000 sq mi) of land.

Coffee is used as a food plant by the larvae of some Lepidoptera (butterfly and moth) species including Dalcera abrasa, Turnip Moth and some members of the genus Endoclita, including E. damor and E. malabaricus.

There are several pests that affect coffee production, including the coffee borer beetle (Hypothenemus hampei) and the coffee leafminer Leucoptera caffeina.

Shade-grown coffee

Main article: Shade-grown coffee

Coffee farmer in Ethiopia.

In its natural environment, coffee most often grows in the shade. However, most cultivated coffee is produced on full-sun, monocropping plantations, as are most commercial crops, in order to maximize production per unit of land. This practice is, however, detrimental to the natural environment since the natural habitats which existed prior to the establishment of the plantations are destroyed, and all non-Coffea flora and fauna are suppressed - often with chemical pesticides and herbicides. Shade-grown coffee is favored by conservationists, since it permits a much more natural, complex ecosystem to survive on the land occupied by the plantation. Also, it naturally mulches the soil it grows in, lives twice as long as sun-grown varieties, and depletes less of the soil's resources - hence less fertilizer is needed. In addition, shade-grown coffee is considered by some to be of higher quality than sun-grown varieties, as the cherries produced by the Coffea plants in the shade are not as large as commercial varieties; some believe that this smaller cherry concentrates the flavors of the cherry into the seed (bean) itself. Shade-grown coffee is also associated with environmentally friendly ecosystems that provide a wider variety and number of migratory birds than those of sun-grown coffee farms.

Chemistry of green coffee beans

Coffea arabica branch with immature fruit - Brazil

The term reen coffee bean refers to un-roasted mature or immature coffee beans. These have been processed by wet or dry method for removing the outer pulp and mucilage, and have an intact wax layer on the outer surface. When immature, they are green. When mature, they have a brown to yellow or reddish color, and typically weigh 300 to 330 mg per dried coffee bean. Non-volatile and volatile compounds in green coffee beans, such as caffeine, deter many insects and animals from eating them. Further, both non-volatile and volatile compounds contribute to the flavor of the coffee bean when it is roasted. Non-volatile nitrogenous compounds (including alkaloids, trigonelline, proteins and free amino acids) and carbohydrates are of major importance in producing the full aroma of roasted coffee, and for its biological action.

Non-volatile alkaloids

Caffeine (1,3,7-trimethyl-xanthine) is the alkaloid most present in green and roasted coffee beans. The content of caffeine is between 1% and 2.5% w/w of dry green coffee beans. The content of caffeine does not change during maturation of green coffee beans. Lower concentrations of theophylline, theobromine, paraxanthine, liberine, and methylliberine can be found. The concentration of theophylline, an alkaloid noted for its presence in green tea, is reduced during the roasting process (usually about 15 minutes at 230 C), whereas the concentration of most other alkaloids are not changed. The solubility of caffeine in water increases with temperature and with the addition of chlorogenic acids, citric acid, tartaric acid, all of which are present in green coffee beans (e.g. 1 g caffeine dissolves in 46 mL of water at room temperature, and 5.5 mL at 80 C). The xanthine alkaloids are odorless but have a bitter taste in water, which however is masked by organic acids present in green coffee.

Trigonelline (N-methyl-nicotinate) is a derivative of vitamin B6, not as bitter as caffeine. In green coffee beans, the content is between 0.6% (w/w) and 1% (w/w). At roasting temperature (230 C), 85% of the trigonelline is degraded to nicotinic acid, leaving small amounts of the unchanged molecule in the roasted beans. In green coffee beans, trigonelline is synthesized from nicotinic acid (pyridinium-3-carboxylic acid) by methylation from methionine, a sulfur-containing amino acid. Mutagenic activity of trigonelline has been reported.

Proteins and amino acids

Proteins account for 8% (w/w) to 12% (w/w) of dried green coffee beans. Major part of the proteins are of the of 11-S-storage kind(alpha - component of 32 kDa, beta component of 22 kDa), most of which are degraded to free amino acids during maturation of green coffee beans. Further, 11-S-storage proteins are degraded to their individual amino acids under roasting temperature and are thus an additional source of bitter components due to generation of Maillard products. High temperature, oxygen concentration and low pH degrade 11-S-storageroteins of green coffee beans to low molecular weight peptides and amino acids. The degradation is accelerated in the presence of organic acids such as chlorogenic acids and their derivatives. Other proteins include enzymes, such as catalase and polyphenol oxidase, which are important for the maturation of green coffee beans. Mature coffee contains free amino acids (4.0 mg amino acid / g robusta coffee and up to 4 .5 mg amino acid /g arabica coffee). In Coffea arabica, alanine is the amino acid with the highest concentration, i.e. 1.2 mg / g followed by asparagine of 0.66 mg/g, whereas in C. robusta, alanine is present at a concentration of 0.8 mg/g and asparagine at 0.36 mg/g. The free hydrophobic amino acids in fresh green coffee beans contribute to the unpleasant taste making it impossible to prepare a beverage with such compounds. In fresh green coffee from Peru, these concentrations have been determined as follows: isoleucine 81 mg /kg, leucine 100 mg/kg, valine 93 mg/kg, tyrosine 81 mg/kg, phenylalanine 133 mg /kg. The concentration of gamma-aminobutyric acid (a neurotransmitter) has been determined between 143 mg/ kg and 703 mg/kg in green coffee beans from Tanzania. Roasted coffee beans do not contain any free amino acids, the amino acids in green coffee beans are degraded under roasting temperature to Maillard products (reaction products between the aldehyde group of sugar and the alpha-amino-group of the amino acids). Further, diketopiperazines, e.g. cyclo(proline-proline), cyclo(proline-leucine), cyclo(proline-isoleucine), are generated from the corresponding amino acids, and are the major source of the bitter taste of roasted coffee. The bitter flavor of diketopiperazines is perceptible at around 20 mg/ 1 liter water. The content of diketopiperazines in espresso is about 20 mg to 30 mg which is responsible for its bitterness.

Carbohydrates

Carbohydrates make up about 50% of the dry weight of green coffee beans. The carbohydrate fraction of green coffee is dominated by polysaccharides, such as arabinogalactan, galactomannan and cellulose, contributing to the tasteless flavor of green coffee. Arabinogalactan makes up to 17% of dry weight of green coffee beans with a molecular weight of 90 kDa to 200 kDa. It is composed of beta-1-3-linked galactan main chain with frequent members of arabinose (pentose) and galactose (hexose) residues at the side chains comprising immunomodulating properties by stimulating the cellular defense system (Th-1 response) of the body. Mature brown to yellow coffee beans contain fewer residues of galactose and arabinose at the side chain of the polysaccharides, making the green coffee bean more resistant to physical breakdown and less soluble in water. The molecular weight of the arabiniogalactan in coffee is higher than in most other plants, improving the cellular defense system of the digestive tract compared to arabinogalactan with lower molecular weight. Free monosaccharides are present in mature brown to yellow-green coffee beans. The free part of monosaccharides contains sucrose (gluco-fructose) up to 9000 mg/ 100g of arabica green coffee bean, a lower amount in robustas, i.e. 4500 mg/100g. In arabica green coffee beans the content of free glucose was 30 mg to 38 mg / 100 g, free fructose 23 mg to 30 mg/ 100 g; free galactose 35 mg/ 100g and mannitol 50 mg/100g dried coffee beans, respectively. Mannitol is a powerful scavenger for hydroxyl radicals, which are generated during the peroxidation of lipids in biological membranes.

Lipids

The lipids found in green coffee include: linoleic acid, palmitic acid, oleic acid, stearic acid, arachidic acid, diterpenes, triglycerides, unsaturated long-chain fatty acids, esters and amides. The total content of lipids in dried green coffee is between 11.7 g and 14 g / 100 g. Lipids are present on the surface and in the interior matrix of green coffee beans. On the surface they include derivatives of carboxylic acid-5-hydroxytryptamides with an amide bond to fatty acids (unsaturated C6 to C24) making up to 3% (w/w) of total lipid content or 1200 to 1400 microgram / g dried green coffee bean. Such compounds form a wax cover on the surface of the coffee bean (200 mg to 300 mg lipids / 100 g dried green coffee beans) protecting the interior matrix against oxidation and insects. Further, such molecules have anti-oxidative activity due to their chemical structure. Lipids of the interior tissue are triglycerides, linoleic acid (46% of total free lipids), palmitic acid (30% to 35% of total free lipids), and esters. Arabica have a higher content of lipids (13,5 g to 17,4 g lipids/100 g dried green coffee beans) than robustas (9,8 g to 10,7 g lipids / 100 g dried green coffee beans). The content of diterpenes is about 20% of the lipid fraction. The diterpenes found in green coffee include cafestol, kahweol, 16-O-methyl-kafestol, cafestal, kahweal. Diterpenes are known for their in-vitro protection of liver tissue against chemical oxidation. In coffee oil from green coffee beans the diterpenes are esterified with saturated long chain fatty acids.

Non-volatine chlorogenic acids

Chlorogenic acids belong to a group of compounds known as polyphenols, which are antioxidants. The content of chlorogenic acid in dried green coffee beans of robusta is 65 mg/g and of arabica 140 mg/g, depending on the timing of harvesting. At roasting temperature, more than 70% of chlorogenic acids are destroyed, leaving a residue of less than 30 mg/g in the roasted coffee bean. In contrast to green coffee, green tea contains an average of 85 mg/g polyphenols. These chlorogenic acids could be a valuable inexpensive source of antioxidants. Chlorogenic acids are homologous compounds comprising caffeic acid, ferulic acid and 3,4 dimethoxycinnamic acid which are connected by an ester-bond to the hydroxyl groups of quinic acid (1alpha, 3R, 4alpha, 5R-tetrahydroxy-cyclohexane carboxylic acid) The anti-oxidation capacity of chlorogenic acid is more potent than of ascorbic acid (vitamin C) or mannitol, which is a selective hydroxy-radical scavenger. Chlorogenic acids have a bitter taste in low concentrations such as 50 mg/L water. At higher concentrations of 1g/L water they have a sour taste. Chlorogenic acids increase the solubility of caffeine and are important modulators of taste.

Volatile compounds

Volatile compounds of green coffee beans include short chain fatty acids, aldehydes, and nitrogen containing aromatic molecules, such as derivatives of pyrazines green-herbeaceous-earthy odor. Briefly, such volatile compounds are responsible for the unpleasant odor and taste of green coffee being capable of causing nausea and vomiting upon inhaling of the odor of ground green coffee beans or ingestion of a beverage made by pulverised green coffee beans. Due to this nauseating odor, green coffee beans have never been used by themselves for the preparation of a refreshing beverage; such a beverage would cause vomiting, although green coffee beans contain the same amount of caffeine as roasted coffee. When green coffee beans are roasted, other molecules with the typical pleasant aroma of coffee are generated, which are not present in fresh green coffee. Some have tried to neutralise or transform the nauseating odor-molecules of green coffee beans, producing an innovative flavor by fermentation of the intact mature brown to yellow coffee bean similar to the wet processing of the mature coffee fruit. However, fermented green coffee beans must be further roasted in order to obtain an organoleptic accepted beverage based on coffee. During roasting, the major part of the unpleasant tasting volatile compounds are neutralised. Unfortunately, other important molecules such as antioxidants and vitamins present in green coffee are destroyed. Volatile compounds with nauseating odor for humans have been identified, including acetic acid (pungent, unpleasant odor); propionic acid (odor of sour milk, or butter); butanoic acid (odor of rancid butter, present in green coffee with 2 mg/100 g coffee beans); pentanoic acid (unpleasant fruity flavor, present in green coffee at 40 mg/100 g in coffee beans); hexanoic acid (fatty-rancid odor), heptanoic acid (fatty odor); octanoic acid (repulsive oily rancid odor); nonanoic acid (mild nut-like fatty odor); decanoic acid (sour repulsive odor); and derivatives of such fatty acids; 3-methyl-valeric acid (sour, green-herbaceous, unpleasant odor); acetaldehyde (pungent-nauseating odor, even when highly diluted; present in dried green coffee beans at concentrations of about 5 mg/1 kg); propanal (choking effect on respiratory system, penetrating-nauseating), butanal (nauseating effect; present in dried green coffee beans at 2 to 7 mg/1 kg); pentanal or valerianic aldehyde (very repulsive nauseating effect).

Health properties

Extracts of green coffee have been shown to improve vasoactivity (the ability of the blood vessels to contract or expand freely) in humans.

New coffee species

Recently, two new species of coffee plants have been discovered in Cameroon: Coffea charrieriana and Coffea anthonyi. These species could introduce two new features to cultivated coffee plants: 1) beans without caffeine and 2) self-pollination. By crossing the new species with other known coffees (e.g., C. arabica and C. robusta), new coffee hybrids might allow these new improvements at regular coffee plantations (e.g. in Kenya, since C. arabica and C. robusta are accustomed to these growing conditions).. In 2008 and 2009, researchers from the Royal Botanic Gardens, Kew named seven species of Coffea from the mountains of northern Madagascar, including C. ambongensis, C. boinensis, C. labatii, C. pterocarpa, C. bissetiae, and C. namorokensis.

See also

Coffee

Coffee production in Colombia

Jamaican Blue Mountain Coffee

Kopi Luwak

List of coffee companies

References

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^ TEUTSCH, IA, 2004, Einfluss der Rohkaffeeverarbeitung auf Aromastoffvernderungen in gersteten Kaffeebohnen sowie im Kaffeebetrnk, PhD Thesis, Department of Chemistry, Technical University Munich, Germany; www.deposit.ddb.de/cgi-bin/dokserv?idn=97339305x& dok_var=d1&dok_ext=pdf&filename=97339305x.pdf

^ GINZ, M, 2001, Bittere Diketopiperazine und chlorogensurederivate in Roestkaffee, PhD-thesis, Technical University Carolo-Wilhelminia, Brunswig, Germany, www.digibib.tu-bs.de/?docid=00001257 - 17k

^ Redgwell RJ, Curti D, Rogers J, Nicolas P, Fischer M (June 2003). "Changes to the galactose/mannose ratio in galactomannans during coffee bean (Coffea arabica L.) development: implications for in vivo modification of galactomannan synthesis". Planta 217 (2): 31626. doi:10.1007/s00425-003-1003-x. PMID 12783340. 

^ GOTODA, N, IWAI, K, Arabinogalactan isolated from coffee beans indicates immunomodulating properties, p. 116-120; In: Association for Science and Information on Coffee, (ASIC) 21st International Conference on Coffee Science, 11 15 September 2006, Montpellier, France

^ TRESSEL, R, HOLZER, M and KAMPERSCHROER, H, 1983, Bildung von Aromastoffenin Roestkaffee in Abhaengigkeit vom Gehalt an freien Aminosaeren und reduzierenden Zuckern; 10th International Colloquium Chemicum Coffee, Salvador, Bahia 11 October to 14 Oct; ASIC publication 1983, p279-292

^ ROFFI, J, CORTE DOS SANTOS, A, MEXIA, JT, BUSSON, F, and MIAGROT, M, 1973, Caf verts et torrefiesde l Angola. Etude chimique, 5th International Colloquium Chemicum Coffee, Lisboa, 14 June to 19 June 1971; published by ASIC 1973, pp 179-200

^ Clifford MN (1985). "Chemical and physical aspects of green coffee and coffee products". in Clifford MN, Wilson KC. Coffee: botany, biochemistry, and production of beans and beverage. London: Croom Helm AVI. pp. 30574. ISBN 0-7099-0787-7. 

^ Lee KJ, Jeong HG (September 2007). "Protective effects of kahweol and cafestol against hydrogen peroxide-induced oxidative stress and DNA damage". Toxicol. Lett. 173 (2): 807. doi:10.1016/j.toxlet.2007.06.008. PMID 17689207. 

^ CLIFFORD, M.N, 2006, Chlorogenic acids their characterisation, transformation during roasting, and potential dietary significance, In: Association for Science and Information on Coffee, (ASIC) 21st International Conference on Coffee Science, 11 15 September 2006, Montpellier, France, p 36-49

^ MORISHITA, H., KIDO, R., 1995; Anti-oxydant activities of chlorogenic acid; 16th international colloqu. Chem. Coffee, Kyoto 9-14, April 1995, ASIC-1995

^ US patent application No 20070190207; Method of processing green coffee beans, http://appft1.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070190207%22.PGNR.&OS=DN/20070190207&RS=DN/20070190207

^ Bessire-Thomas, Yvonne; Ivon Flament (2002). Coffee flavor chemistry. Chichester: John Wiley & Sons. ISBN 0-471-72038-0. 

^ OCHIAL, R, JOKURA, H, et al., Green coffee bean extract improves human vasoactivity, Association for Science and Information on Coffee, p731736; ASIC 21st International Conference on Coffee Science, 1115 September 2006, Montpellier, France

^ Science Connection 22 (July 2008)

^ "Seven species of wild coffee amongst Kew's haul of new discoveries" Royal Botanic Gardens, Kew, 22 December 2009.

External links

Wikimedia Commons has media related to: Coffea

Wikispecies has information related to: Coffea

Coffea arabica by James A. Duke detailed information about this species.

Article about the nutritional needs of coffee plants.

University of Hawaii spreadsheets dealing with costs of production including those of coffee growing in Hawaii.

Farmers Bookshelf guide to coffee growing and processing in Hawaii.

United States Department of Agriculture Foreign Agriculture Service (Source of coffee (and other commodities) production and consumption data).

Coffee & Conservation - Many resources on sustainable coffee, including reviews, especially shade coffee and biodiversity

v  d  e

Coffee

Production by country

Brazil  Colombia  Costa Rica  Ecuador  El Salvador  Ethiopia  Guatemala  Haiti  India  Indonesia  Jamaica  Kenya  Papua New Guinea  Philippines   USA  Vietnam

Coffee topics

History of coffee  Economics of coffee  Coffee and health  Coffee and the environment

Species and varieties

List of varieties  Coffea arabica: Kenya AA, Kona, Jamaican Blue Mountain  Coffea canephora (Coffea robusta): Kopi Luwak  Coffea liberica: Kape Barako  Single-origin

Major chemicals in coffee

Cafestol  Caffeic acid  Caffeine

Coffee processing

Coffee roasting  Decaffeination  Home roasting coffee

Coffee preparation

Coffeemaker  Coffee percolator  Espresso (lungo, ristretto)  Espresso machine  Drip brew  French press  Turkish coffee  Vacuum coffee maker  Instant coffee  Chemex  Moka pot  AeroPress  Presso  Knockbox

Popular coffee beverages

Affogato  Americano  Bicerin  C ph s   Caf au lait  Caf con leche  Caf Cubano  Cafe mocha  Caff corretto  Caff macchiato  Cappuccino  Carajillo  Coffee milk  Cortado  Espresso  Flat white  Frappuccino  Galo  Greek frapp coffee  Iced coffee  Indian filter coffee  Ipoh white coffee  Irish coffee  Latte  Latte macchiato  Liqueur coffee  Long black  Red eye  Ristretto

Coffee substitutes

Barley tea  Barleycup  Caro  Chicory  Dandelion coffee  Pero  Postum  Roasted grain beverage

Coffee and lifestyle

Barista  Caf  Caff  Caff sospeso  Coffee break  Coffee ceremony  Coffee culture  Coffee cupping  Coffee Palace  Coffeehouse  Fika  Kopi tiam  List of coffeehouse chains  Viennese caf

Categories: Granular materials | Herbal and fungal stimulants | Medicinal plants | CoffeaHidden categories: All articles with unsourced statements | Articles with unsourced statements from October 2009 | Articles lacking in-text citations from February 2008 | All articles lacking in-text citations

Airbag

China Product


Terminology

Because no action by the vehicle occupant is required to activate or use the airbag, it is considered a passive safety device. This is in contrast to seat belts, which are considered active safety devices because the vehicle occupant must act to enable them. Terminological confusion can arise from the fact that passive safety devices and systems those requiring no input or action by the vehicle occupant can themselves operate in an active manner; an airbag is one such device. Vehicle safety professionals are generally careful in their use of language to avoid this sort of confusion, though advertising principles sometimes prevent such syntactic caution in the consumer marketing of safety features.

Various manufacturers have over time used different terms for airbags. General Motors' first bags, in the 1970s, were marketed as the Air Cushion Restraint System. Common terms in North America include Supplemental Restraint System (SRS) and Supplemental Inflatable Restraint (SIR); these terms reflect the airbag system's nominal role as a supplement to active restraints, i.e., seat belts. 200cc dirt bike

History dirt bike 200cc

1975 Buick Electra with ACRS 80cc dirt bike

In 1994, Ford of Europe made airbags standard equipment in all the cars they built

Invention

An American inventor, John Wenrick, a retired industrial engineer, designed the original safety cushion for automotive use in 1952 at his kitchen table. His patent lasted only 17 years - long before mainstream automotive usage. Dr. David S. Breed, invented and developed a key component for automotive use: the ball-in-tube inertial sensor for crash detection. Breed Corporation then marketed this innovation first in 1967 to Chrysler. A similar "Auto-Ceptor" crash-restraint, developed by Eaton, Yale & Towne Inc. for Ford was soon offered as an automatic safety system in the USA, while the Italian Eaton-Livia company offered a variant with localized air cushions.

As a supplement to seatbelts

Airbags for passenger cars were introduced in the United States in the mid-1970s, when seat belt usage rates in the country were quite low. Ford built an experimental fleet of cars with airbags in 1971, followed by General Motors in 1973 on Chevrolet vehicles. The early fleet of experimental GM vehicles equipped with airbags experienced seven fatalities, one of which was later suspected to have been caused by the airbag.

In 1974, GM made the ACRS or "Air Cushion Restraint System" available as a regular production option (RPO code AR3) in some full-size Buick, Cadillac and Oldsmobile models. The GM cars from the 1970s equipped with ACRS have a driver side airbag, a driver side knee restraint (which consists of a padded lower dashboard) and a passenger side airbag. The passenger side airbag, protects both front passengers and unlike most newer ones, it integrates a knee cushion, a torso cushion and it also has dual stage deployment which varies depending on the force of the impact. The cars equipped with ACRS have lap belts for all seating positions but they do not have shoulder belts. These were already mandatory equipment in the United Stated on closed cars without airbags for the driver and outer front passenger seating positions.

The automotive industry's first passenger side knee airbag (not separate) was already used on the 1970s General Motors cars, it was integrated in the passenger airbag that had a knee cushion and a torso cushion.[citation needed]

The development of airbags coincided with an international interest in automobile safety legislation. Some safety experts advocated a performance-based occupant protection standard rather than a standard mandating a particular technical solution, which could rapidly become outdated and might not be a cost-effective approach. As countries successively mandated seat belt restraints, there was less emphasis placed on other designs for several decades.

Manufacturers emphasise that an airbag is not, and can not be an alternative to seatbelts. They emphasise that they are only supplemental to a seatbelt. Hence the commonly used term "Supplemental Restraint System" or SRS. It is vitally important that drivers and passengers are aware of this. In the majority of cases of death caused by air bags, seat belts were not worn.[citation needed]

As a supplemental restraint

Frontal airbag

The auto industry and research and regulatory communities have moved away from their initial view of the airbag as a seat belt replacement, and the bags are now nominally designated as Supplemental Restraint System (SRS) or Supplemental Inflatable Restraints.

In 1980, Mercedes-Benz introduced the airbag in Germany. as an option on its high-end S-Class (W126). In the Mercedes system, the sensors would automatically pre-tension the seat belts to reduce occupant's motion on impact (now a common feature), and then deploy the airbag on impact. This integrated the seat belts and airbag into a restraint system, rather than the airbag being considered an alternative to the seat belt.

In 1987, the Porsche 944 turbo became the first car in the world to have driver and passenger airbags as standard equipment. The Porsche 944 and 944S had this as an available option. The same year also saw the first airbag in a Japanese car, the Honda Legend.

Airbags became common in the 1980s, with Chrysler and Ford introducing them in the mid-1980s; it was Chrysler that made them standard equipment across its entire line in 1990 (except for trucks until 1995).[citation needed]

Audi was relatively late to offer airbag systems on a broader scale; until the 1994 model year, for example, the 80/90, by far Audi's 'bread-and-butter' model, as well as the 100/200, did not have airbags in their standard versions. Instead, the German automaker until then relied solely on its proprietary procon-ten restraint system.

In Europe, airbags were almost entirely absent from family cars until the early 1990s, except for Saab, who made them standard on the 900 Turbo in 1989 and on all models in 1990. The first European Ford to feature an airbag was the facelifted Escort MK5b in 1992; within a year, the entire Ford range had at least one airbag as standard. By the mid 1990s, European market leaders such as Vauxhall/Opel, Rover, Peugeot, Renault and Fiat had included airbags as at least optional equipment across their model ranges. By the end of the decade, it was very rare to find a mass market car without an airbag, and some late 1990s products, such as the Volkswagen Golf Mk4 also featured side airbags. The Peugeot 306 was a classical example of how commonplace airbags became on mass market cars during the 1990s. On its launch in early 1993 most of the range did not even have driver airbags as an option. By 1999 however, side airbags were available on several variants.

During the 2000s side airbags were commonplace on even budget cars, such as the smaller-engined versions of the Ford Fiesta and Peugeot 206, and curtain airbags were also becoming regular features on mass market cars. The Toyota Avensis, launched in 1998, was the first mass market car to be sold in Europe with a total of nine airbags. Although in some countries, such as Russia, airbags are still not standard equipment on all cars, such as those from Lada.

Variable force deployment front airbags were developed to help minimize injury from the airbag itself.

Shaped airbags

The Citron C4 provides the first "shaped" driver airbag, made possible by this car's unusual fixed hub steering wheel.

Side airbag

Side airbag inflated permanently for display purposes

A deployed curtain airbag in a Opel Vectra

There are essentially two types of side airbags commonly used today, the side torso airbag and the side curtain airbag.

Most vehicles equipped with side curtain airbags also include side torso airbags. However some exceptions such as the Chevrolet Cobalt, 2007-09 model Chevrolet Silverado/GMC Sierra, and 2009-10 Dodge Ram do not feature the side torso airbag.

Side torso airbag

Side-impact airbags or side torso airbags are a category of airbag usually located in the seat, and inflate between the seat occupant and the door. These airbags are designed to reduce the risk of injury to the pelvic and lower abdomen regions. Some vehicles are now being equipped with different types of designs, to help reduce injury and ejection from the vehicle in rollover crashes.

The Swedish company Autoliv AB, was granted a patent on side airbags, and they were first offered as an option in 1994 on the 1995 model year Volvo 850, and as standard equipment on all Volvo cars made after 1995.

Side tubular or curtain airbag

In late 1997 the 1998 model year BMW 7-series and E39 5-series were fitted with a tubular shaped head side airbags, the "Head Protection System (HPS)" as standard equipment. This is an industry's first in offering head protection in side impact collisions. This airbag also maintained inflation for up to seven seconds for rollover protection. However, this tubular shaped airbag design has been quickly replaced by an inflatable 'curtain' airbag for superior protection.

In May 1998 Toyota began offering the first side curtain airbag deploying from the roof on the Progrs. In 1998 the Volvo S80 was first given curtain airbags to protect both front and rear passengers. They were then made standard equipment on all new Volvo cars from 1998 and while initially seat-mounted later versions deployed from the roof.

Roll-sensing side curtain airbags found on vehicles more prone to rollovers such as SUV's and pickups will deploy when a rollover is detected instead of just when an actual collision takes place. Often there is a switch to disable the feature in case the driver wants to take the vehicle offroad.

Curtain airbags have been said to reduce brain injury or fatalities by up to 45% in a side impact with an SUV. These airbags come in various forms (e.g., tubular, curtain, door-mounted) depending on the needs of the application. Many recent SUVs and MPVs have a long inflatable curtain airbag that protects all 3 rows of seats.

Knee airbag

The first driver's side and separate knee airbag was used in the 1996 model Kia Sportage vehicle and has been standard equipment since then. The airbag is located beneath the steering wheel. The Toyota Avensis became the first vehicle sold in Europe equipped with a driver's knee airbag. The EuroNCAP reported on the 2003 Avensis, "There has been much effort to protect the driver's knees and legs and a knee airbag worked well." Since then certain models have also included front passenger knee airbags, which deploy near or over the glove compartment in a crash. Knee airbags are designed to reduce leg injury. The knee airbag has become increasingly common in the 2000s, with a large minority of cars featuring them on the driver side by 2010. Passenger knee airbags remain extremely rare.

Rear curtain airbag

In 2008, the Toyota iQ launched featuring the first production rear curtain shield airbag to protect the rear occupants' heads in the event of a rear end impact.

Center airbag

In 2009, Toyota developed the first production rear-seat center airbag designed to reduce the severity of secondary injuries to rear passengers in a side collision. This system deploys from the rear center console first appearing in on the redesigned Crown Majesta.

Seat belt airbag

In 2009, the S-class ESF safety concept car showcased seatbelt airbags. They will be included standard on the production Lexus LFA in late 2010, and the 2011 Ford Explorer will offer rear seatbelt airbags as an option.

On motorcycles

Various types of airbags were tested on motorcycles by the UK Transport Research Laboratory in the mid 1970s. In 2006 Honda introduced the first production motorcycle airbag safety system on its Gold Wing motorcycle. Honda claims that sensors in the front forks can detect a severe frontal collision and decide when to deploy the airbag, absorbing some of the forward energy of the rider and reducing the velocity at which the rider may be thrown from the motorcycle.

Airbag suits have also been developed for use by Motorcycle Grand Prix riders. They are connected to the motorcycle by a cable and deploy when the cable becomes detached from its mounting clip, inflating to protect the back.

How airbags work

An ACU from a Geo Storm.

The design is conceptually simple; a central "Airbag control unit" (ACU) (a specific type of ECU) monitors a number of related sensors within the vehicle, including accelerometers, impact sensors, side (door) pressure sensors, wheel speed sensors, gyroscopes, brake pressure sensors, and seat occupancy sensors. When the requisite 'threshold' has been reached or exceeded, the airbag control unit will trigger the ignition of a gas generator propellant to rapidly inflate a nylon fabric bag. As the vehicle occupant collides with and squeezes the bag, the gas escapes in a controlled manner through small vent holes. The airbag's volume and the size of the vents in the bag are tailored to each vehicle type, to spread out the deceleration of (and thus force experienced by) the occupant over time and over the occupant's body, compared to a seat belt alone.

The signals from the various sensors are fed into the Airbag control unit, which determines from them the angle of impact, the severity, or force of the crash, along with other variables. Depending on the result of these calculations, the ACU may also deploy various additional restraint devices, such as seat belt pre-tensioners, and/or airbags (including frontal bags for driver and front passenger, along with seat-mounted side bags, and "curtain" airbags which cover the side glass). Each restraint device is typically activated with one or more pyrotechnic devices, commonly called an initiator or electric match. The electric match, which consists of an electrical conductor wrapped in a combustible material, activates with a current pulse between 1 to 3 amperes in less than 2 milliseconds. When the conductor becomes hot enough, it ignites the combustible material, which initiates the gas generator. In a seat belt pre-tensioner, this hot gas is used to drive a piston that pulls the slack out of the seat belt. In an airbag, the initiator is used to ignite solid propellant inside the airbag inflator. The burning propellant generates inert gas which rapidly inflates the airbag in approximately 20 to 30 milliseconds. An airbag must inflate quickly in order to be fully inflated by the time the forward-traveling occupant reaches its outer surface. Typically, the decision to deploy an airbag in a frontal crash is made within 15 to 30 milliseconds after the onset of the crash, and both the driver and passenger airbags are fully inflated within approximately 60-80 milliseconds after the first moment of vehicle contact. If an airbag deploys too late or too slowly, the risk of occupant injury from contact with the inflating airbag may increase. Since more distance typically exists between the passenger and the instrument panel, the passenger airbag is larger and requires more gas to fill it.

Front airbags normally do not protect the occupants during side, rear, or rollover accidents. Since airbags deploy only once and deflate quickly after the initial impact, they will not be beneficial during a subsequent collision. Safety belts help reduce the risk of injury in many types of crashes. They help to properly position occupants to maximize the airbag's benefits and they help restrain occupants during the initial and any following collisions.

In vehicles equipped with a rollover sensing system, accelerometers and gyroscopes are used to sense the onset of a rollover event. If a rollover event is determined to be imminent, side-curtain airbags are deployed to help protect the occupant from contact with the side of the vehicle interior, and also to help prevent occupant ejection as the vehicle rolls over.

Triggering conditions

Airbags are designed to deploy in frontal and near-frontal collisions more severe than a threshold defined by the regulations governing vehicle construction in whatever particular market the vehicle is intended for. U.S. regulations require deployment in crashes at least equivalent in deceleration to a 23 km/h(14 mph) barrier collision, or similarly, striking a parked car of similar size across the full front of each vehicle at about twice the speed. International regulations are performance based, rather than technology-based, so airbag deployment threshold is a function of overall vehicle design.

Unlike crash tests into barriers, real-world crashes typically occur at angles other than directly into the front of the vehicle, and the crash forces usually are not evenly distributed across the front of the vehicle. Consequently, the relative speed between a striking and struck vehicle required to deploy the airbag in a real-world crash can be much higher than an equivalent barrier crash. Because airbag sensors measure deceleration, vehicle speed and damage are not good indicators of whether an airbag should have deployed. Airbags can deploy due to the vehicle's undercarriage striking a low object protruding above the roadway due to the resulting deceleration.

The airbag sensor is a MEMS accelerometer, which is a small integrated circuit with integrated micro mechanical elements. The microscopic mechanical element moves in response to rapid deceleration, and this motion causes a change in capacitance, which is detected by the electronics on the chip that then sends a signal to fire the airbag. The most common MEMS accelerometer in use is the ADXL-50 by Analog Devices, but there are other MEMS manufacturers as well.

Initial attempts using mercury switches did not work well. Before MEMS, the primary system used to deploy airbags was called a "rolamite". A rolamite is a mechanical device, consisting of a roller suspended within a tensioned band. As a result of the particular geometry and material properties used, the roller is free to translate with little friction or hysteresis. This device was developed at Sandia National Laboratories. The rolamite, and similar macro-mechanical devices were used in airbags until the mid-1990s when they were universally replaced with MEMS.

Nearly all airbags are designed to automatically deploy in the event of a vehicle fire when temperatures reach 150-200 C (300-400 F). This safety feature, often termed auto-ignition, helps to ensure that such temperatures do not cause an explosion of the entire airbag module.

Today, airbag triggering algorithms are becoming much more complex. They try to reduce unnecessary deployments (for example, at low speed, no shocks should trigger the airbag, to help reduce damage to the car interior in conditions where the seat belt would be an adequate safety device), and to adapt the deployment speed to the crash conditions. The algorithms are considered valuable intellectual property. Experimental algorithms may take into account such factors as the weight of the occupant, the seat location, seatbelt use, and even attempt to determine if a baby seat is present.

Inflation

When the frontal airbags are to deploy, a signal is sent to the inflator unit within the airbag control unit. An igniter starts a rapid chemical reaction generating primarily nitrogen gas (N2) to fill the airbag making it deploy through the module cover. Some airbag technologies use compressed nitrogen or argon gas with a pyrotechnic operated valve ("hybrid gas generator"), while other technologies use various energetic propellants. Propellants containing the highly toxic sodium azide (NaN3) were common in early inflator designs. However, propellants containing sodium azide were widely phased out during the 1990s in pursuit of more efficient, less expensive and less toxic alternatives.[citation needed]

The azide-containing pyrotechnic gas generators contain a substantial amount of the propellant. The driver-side airbag would contain a canister containing about 50 grams of sodium azide. The passenger side container holds about 200 grams of sodium azide. The incomplete combustion of the charge due to rapid cooling leads to production of carbon monoxide (CO) and nitrogen(II) oxide as reaction by-products.

The alternative propellants may incorporate, for example, a combination of nitroguanidine, phase-stabilized ammonium nitrate (NH4NO3) or other nonmetallic oxidizer, and a nitrogen-rich fuel different than azide (e.g. tetrazoles, triazoles, and their salts). The burn rate modifiers in the mixture may be an alkaline metal nitrate (NO3-) or nitrite (NO2-), dicyanamide or its salts, sodium borohydride (NaBH4), etc. The coolants and slag formers may be e.g. clay, silica, alumina, glass, etc. Other alternatives are e.g. nitrocellulose based propellants (which have high gas yield but bad storage stability, and their oxygen balance requires secondary oxidation of the reaction products to avoid buildup of carbon monoxide), or high-oxygen nitrogen-free organic compounds with inorganic oxidizers (e.g., di or tricarboxylic acids with chlorates (ClO3-) or perchlorates (HClO4) and eventually metallic oxides; the nitrogen-free formulation avoids formation of toxic nitrogen oxides).

From the onset of the crash, the entire deployment and inflation process is about 0.04 seconds faster than the blink of an eye (about 0.2 seconds). Because vehicles change speed so quickly in a crash, airbags must inflate rapidly to reduce the risk of the occupant hitting the vehicle's interior.

Variable-force deployment

Advanced airbag technologies are being developed to tailor airbag deployment to the severity of the crash, the size and posture of the vehicle occupant, belt usage, and how close that person is to the actual airbag. Many of these systems use multi-stage inflators that deploy less forcefully in stages in moderate crashes than in very severe crashes. Occupant sensing devices let the airbag control unit know if someone is occupying a seat adjacent to an airbag, the mass/weight of the person, whether a seat belt or child restraint is being used, and whether the person is forward in the seat and close to the airbag. Based on this information and crash severity information, the airbag is deployed at either a high force level, a less forceful level, or not at all.

Adaptive airbag systems may utilize multi-stage airbags to adjust the pressure within the airbag. The greater the pressure within the airbag, the more force the airbag will exert on the occupants as they come in contact with it. These adjustments allow the system to deploy the airbag with a moderate force for most collisions; reserving the maximum force airbag only for the severest of collisions. Additional sensors to determine the location, weight or relative size of the occupants may also be used. Information regarding the occupants and the severity of the crash are used by the airbag control unit, to determine whether airbags should be suppressed or deployed, and if so, at various output levels.

Post-deployment view of a SEAT Ibiza airbag

Post-deployment

A chemical reaction produces a burst of nitrogen to inflate the bag. Once an airbag deploys, deflation begins immediately as the gas escapes through vent(s) in the fabric (or, as it's sometimes called, the cushion) and cools. Deployment is frequently accompanied by the release of dust-like particles, and gases in the vehicle's interior (called effluent). Most of this dust consists of cornstarch, french chalk, or talcum powder, which are used to lubricate the airbag during deployment. Newer designs produce effluent primarily consisting of harmless talcum powder/cornstarch and nitrogen gas. In older designs using an azide-based propellant (usually NaN3), varying amounts of sodium hydroxide nearly always are initially present. In small amounts this chemical can cause minor irritation to the eyes and/or open wounds; however, with exposure to air, it quickly turns into sodium bicarbonate (baking soda). However, this transformation is not 100% complete, and invariably leaves residual amounts of hydroxide ion from NaOH. Depending on the type of airbag system, potassium chloride (often used as a table salt substitute) may also be present.

For most people, the only effect the dust may produce is some minor irritation of the throat and eyes. Generally, minor irritations only occur when the occupant remains in the vehicle for many minutes with the windows closed and no ventilation. However, some people with asthma may develop a potentially lethal asthmatic attack from inhaling the dust.

Regulatory specifications

United States

On 11 July 1984, the U.S. government amended Federal Motor Vehicle Safety Standard 208 (FMVSS 208) to require cars produced after 1 April 1989 to be equipped with a passive restraint for the driver. An airbag or an automatic seat belt would meet the requirements of the standard. Airbag introduction was stimulated by the U.S. National Highway Traffic Safety Administration. However, airbags were not mandatory on light trucks until 1995.[citation needed]

In 1998, FMVSS 208 was amended to require dual front airbags, and de-powered, or second-generation airbags were also mandated. This was due to the injuries caused by first-generation airbags, though FMVSS 208 continues to require that bags be engineered and calibrated to be able to "save" the life of an unbelted 50th-percentile size and weight "male" crash test dummy.

Outside the U.S.A.

Most countries[who?] outside North America adhere to internationalized European ECE vehicle and equipment regulations rather than the U.S. Federal Motor Vehicle Safety Standards. ECE airbags are generally smaller and inflate less forcefully than U.S. airbags, because the ECE specifications are based around belted crash test dummies. In the United Kingdom, and most other developed countries there is no direct legal requirement for new cars to feature airbags. Instead, the Euro NCAP vehicle safety rating encourages manufacturers to take a comprehensive approach to occupant safety; a good rating can only be achieved by combining airbags with other safety features. Thus almost all new cars now come with at least two airbags as standard.

Maintenance

The examples and perspective in this section may not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page. (September 2008)

Inadvertent airbag deployment while the vehicle is being serviced can result in severe injury, and an improperly installed or defective airbag unit may not operate or perform as intended. Some countries impose restrictions on the sale, transport, handling, and service of airbags and system components. In Germany, airbags are regulated as harmful explosives; only mechanics with special training are allowed to service airbag systems. Under German Federal Law, used but intact airbags are to be detonated under secure conditions, must not be passed on to third parties in any way, and no untrained person is permitted to handle airbags. Purchase is restricted to buying a new replacement unit for immediate installation by the seller's qualified personnel.[citation needed]

Some automakers (such as Mercedes-Benz) call for the replacement of undeployed airbags after a certain period of time to ensure their reliability in an accident. One example is the 1992 S500 which has an expiry date sticker attached to the door pillar. Skoda vehicles say 14 years from the date of manufacture. In this case replacement would be uneconomic as the car would have negligible value at 14 years old, far less than the cost of fitting new airbags.

Injuries and fatalities

This section may require cleanup to meet Wikipedia's quality standards. Please improve this section if you can. (May 2008)

Airbags can injure or kill vehicle occupants. To provide crash protection for occupants not wearing seat belts, U.S. airbag designs trigger much more forcefully than airbags designed to the international ECE standards used in most other countries. Recent airbag controllers can recognize if a belt is used, and alter the bag deployment parameters accordingly.

Injuries such as abrasion of the skin, hearing damage from the extremely loud 165-175 dB deployment explosion, head injuries, eye damage, and broken nose, fingers, hands or arms can occur as the airbag deploys.[citation needed] Most vehicle airbags are inflated using hot gas generated by a chemical process. Using hot gas allows the required pressure to be obtained with a smaller mass of gas than would be the case using lower temperatures. However, the hot gas can pose a risk of thermal burns if it comes in contact with the skin during deployment and occupant interaction. Burns are most common to the arms, face and chest. These burns are often deep dermal or second-degree burns that take longer to heal and risk scarring.[citation needed]

In 1990, the first automotive fatality attributed to an airbag was reported, with deaths peaking in 1997 at 53 in the United States.[citation needed] TRW produced the first gas-inflated airbag in 1994, with sensors and low-inflation-force bags becoming common soon afterwards. Dual-depth (also known as dual-stage) airbags appeared on passenger cars in 1998. By 2005, deaths related to airbags had declined, with no adult deaths and two child deaths attributed to airbags that year. Injuries remain fairly common in accidents with an airbag deployment.

Serious injuries are less common, but severe or fatal injuries can occur to vehicle occupants very near an airbag or in direct contact when it deploys. Such injuries may be sustained by unconscious drivers slumped over the steering wheel, unrestrained or improperly restrained occupants who slide forward in the seat during pre-crash braking, and properly belted drivers sitting very close to the steering wheel.

The increasing use of airbags may actually make rescue work for firefighters, emergency medical service and police officers more dangerous,[citation needed] because of the risk of deployment while the emergency responder is assisting or extracting vehicle occupants.

Improvements in sensing and gas generator technology have allowed the development of third generation airbag systems that can adjust their deployment parameters to size, weight, position and restraint status of the occupant. These improvements have demonstrated a reduced injury risk factor for small adults and children who had an increased risk of injury with first generation airbag systems.

Airbag fatality statistics

From 1990 to 2008, the U.S. National Highway Traffic Safety Administration identified 175 fatalities caused by air bags. Most of these (104) have been children, while the rest are adults. About 3.3 million air bag deployments have occurred and the agency estimates more than 6,377 lives saved and countless injuries prevented.

A rear-facing infant restraint put in the front seat of a vehicle places an infant's head close to the airbag, which can cause severe head injuries, or death if the airbag deploys. Some modern cars include a switch to disable the front passenger airbag (although not in Australia, where rear-facing child seats are prohibited in the front where an airbag is fitted), in case a child-supporting seat is used there.

In vehicles with side airbags, it is dangerous for occupants to lean against the windows, doors, and pillars, or to place objects between themselves and the side of the vehicle. Articles hung from a vehicle's clothes hanger hooks can be hazardous if the vehicle's side curtain airbags deploy.

Aerospace and military applications

NASA engineers test the Mars Pathfinder airbag landing system on simulated Martian terrain

The aerospace industry and the US Government have applied airbag technologies for many years. NASA, and US DoD have incorporated airbag systems in various aircraft and spacecraft applications as early as the 1960s.

OH-58D CABS test

Airbag landing systems

The first use of airbags for landing were Luna 9 and Luna 13, which landed on the Moon in 1966 and returned panoramic images. The Mars Pathfinder lander employed an innovative airbag landing system, supplemented with aerobraking, parachute, and solid rocket landing thrusters. This prototype successfully tested the concept, and the two Mars Exploration Rover Mission landers employed similar landing systems. The Beagle 2 Mars lander also tried to use airbags for landing, but the landing was unsuccessful for reasons which are not entirely known.

Occupant protection

The US Army has incorporated airbags in its UH-60A/L Black Hawk and OH-58D Kiowa Warrior helicopter fleets. The Cockpit Air Bag System (CABS) consists of forward and lateral airbags with an Electronic Crash Sensor Unit (ECSU). The CABS system was conceived and developed by the US Army Aviation Applied Technology Directorate, Fort Eustis, Va. It is the first conventional airbag system for occupant injury prevention designed and developed specifically for helicopter applications.

See also

Airplane airbags

Automobile safety

Safety standards

Precrash system

Airbag dermatitis

References

^ Bags, Buckles, and Belts: The Debate over Mandatory Passive Restraints in Automobiles

^ U.S. air bag history

^ U.S. patent 6272412 - Passive restraint control system for vehicles

^ Passive Seatbelt Systems and the 65 MPH Speed Limit: A Cause for Concern

^ New York State memo re insurance discounts for passive restraints

^ Popular Science May, 1968

^ http://web.mit.edu/invent/iow/breed.html

^ a b Safety Design, John Fenton, The Times Jan 24 1969

^ GM's ACRS

^ "240 Landmarks of Japanese Automotive Technology - Subaru Legend airbag system". Jsae.or.jp. http://www.jsae.or.jp/autotech/data_e/7-3e.html. Retrieved 2009-12-08. 

^ Wilson, Robert (3 August 2005). "Citroen C4". The Australian. http://www.theaustralian.news.com.au/story/0,20867,16128857-13232,00.html. Retrieved 3 November 2009. 

^ http://www.iihs.org/ratings/ratingsbyseries.aspx?id=527

^ http://www.iihs.org/ratings/rating.aspx?id=1087

^ BMW Head Protection System Sets New Standard in Side-Impact Protection in Latest IIHS Crash Test

^ "Toyota to Make Side Airbags and Curtain Shield Airbags Standard on All New Passenger Vehicle Models in Japan". Theautochannel.com. 2007-07-23. http://www.theautochannel.com/news/2007/07/23/055878.html. Retrieved 2009-12-08. 

^ NHTSA Side-Impact Airbags

^ "Kia Motors' Knee Airbag System | Firehouse.com". Cms.firehouse.com. http://cms.firehouse.com/web/online/University-of-Extrication/Kia-Motors-Knee-Airbag-System/19$708. Retrieved 2009-12-08. 

^ [dead link]

^ "Toyoda Gosei". Toyoda Gosei. 2003-06-30. http://www.toyoda-gosei.com/news/2003/030630.html. Retrieved 2009-12-08. 

^ "For safer cars | Toyota Avensis". Euro NCAP. http://www.euroncap.com/tests/toyota_avensis_2003/172.aspx. Retrieved 2009-12-08. 

^ Abuelsamid, Sam (2009-03-23). "Toyota develops rear curtain airbag for tiny iQ Autoblog Green". Autobloggreen.com. http://www.autobloggreen.com/2008/09/30/toyota-develops-rear-curtain-airbag-for-tiny-iq/. Retrieved 2009-12-08. 

^ Hellwig, Ed (2009-03-11). "Toyota Unveils First Rear Seat Center Airbag". Blogs.edmunds.com. http://blogs.edmunds.com/straightline/2009/03/toyota-unveils-first-rear-seat-center-airbag.html. Retrieved 2009-12-08. 

^ Motorcycle News '06 Wing gets airbag 2 September 2005

^ Motorcycle News Dainese airbag suit in action 21 November 2007

^ Airbag control unit at Audi.com Glossary

^ Media Center at Continental.com

^ Safercar.gov

^ "What You Need to Know About Air Bags, DOT HS 809 575". Nhtsa.dot.gov. http://www.nhtsa.dot.gov/people/injury/airbags/airbags03/page3.html. Retrieved 2009-12-08. 

^ ET 08/00: Sodium azide in car airbags poses a growing environmental hazard

^ Air bag inflator - US Patent 5806888

^ Thermally stable nonazide automotive airbag propellants - Patent 6306232

^ http://www-nrd.nhtsa.dot.gov/pdf/nrd-01/Esv/esv16/98S8P12.PDF

^ Frontal impact test description Euro NCAP website

^ NHTSA 49 CFR Parts 552, 571, 585, and 595, Docket Notice

^ a b National Highway Traffic Safety Administration Air Bag Fatalities

^ American Journal of Epidemiology, Association of First- and Second-Generation Airbags with Front Occupant Death in Car Crashes: A Matched Cohort Study, October 4, 2005.

^ Toyota Aurion: User Manual 2006 model - Australia

^ Defenselink article

^ US Army Demonstrates Simula's Cockpit Air Bag System at Helios.com

^ FAS OH-58D article

^ Simula CABS brochure

^ Air Defense concept papers

^ BNET News Release on AHS Annual Forum award

^ Simula Receives Orders for its Cockpit Air Bag Systems at All Business.com

External links

Wikimedia Commons has media related to: Airbags

Airbag Information and Airbag Deployment video in slow motion

Chemistry behind airbags

Internals of airbag module (enclosure removed)

Pictures and details about the 1970s GM Air Cushion Restraint System

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