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111-397: Smoking is a practice in which a substance is combusted and the resulting smoke is typically inhaled to be tasted and absorbed into the bloodstream of a person. Most commonly, the substance used is the dried leaves of the tobacco plant, which have been rolled with a small rectangle of paper into an elongated cylinder called a cigarette . Other forms of smoking include the use of

222-817: A candle 's flame takes the shape of a sphere. ). Microgravity combustion research contributes to the understanding of a wide variety of aspects that are relevant to both the environment of a spacecraft (e.g., fire dynamics relevant to crew safety on the International Space Station ) and terrestrial (Earth-based) conditions (e.g., droplet combustion dynamics to assist developing new fuel blends for improved combustion, materials fabrication processes , thermal management of electronic systems , multiphase flow boiling dynamics, and many others). Combustion processes that happen in very small volumes are considered micro-combustion . The high surface-to-volume ratio increases specific heat loss. Quenching distance plays

333-548: A cash crop . The demand quickly grew as tobacco, referred to as "golden weed", revived the Virginia Company from its failed expeditions in search for gold in the Americas. In order to meet demands from the old world, tobacco was grown in succession, quickly depleting the land. This became a motivator to settle west into the unknown continent, and likewise an expansion of tobacco production. Indentured servants became

444-412: A detonation . The type of burning that actually occurs depends on the degree to which the fuel and oxidizer are mixed prior to heating: for example, a diffusion flame is formed if the fuel and oxidizer are separated initially, whereas a premixed flame is formed otherwise. Similarly, the type of burning also depends on the pressure: a detonation, for example, is an autoignitive reaction front coupled to

555-434: A smoking pipe or a bong . Smoking is primarily practised as a route of administration for psychoactive chemicals because the active substances within the burnt dried plant leaves vaporize and can be airborne-delivered into the respiratory tract , where they are rapidly absorbed into the bloodstream of the lungs and then reach the central nervous system . In the case of tobacco smoking , these active substances are

666-399: A triplet spin state . Bonding can be described with three bonding electron pairs and two antibonding electrons, with spins aligned, such that the molecule has nonzero total angular momentum. Most fuels, on the other hand, are in a singlet state, with paired spins and zero total angular momentum. Interaction between the two is quantum mechanically a " forbidden transition ", i.e. possible with

777-444: A cigarette, a short-circuited wire) and the persistent combustion of biomass behind the flaming fronts of wildfires . Spontaneous combustion is a type of combustion that occurs by self-heating (increase in temperature due to exothermic internal reactions), followed by thermal runaway (self-heating which rapidly accelerates to high temperatures) and finally, ignition. For example, phosphorus self-ignites at room temperature without

888-423: A fetus. Smoking is a risk factor strongly associated with periodontitis and tooth loss . The effects of smoking on periodontal tissues depend on the number of cigarettes smoked daily and the duration of the habit. A study showed that smokers had 2.7 times and former smokers 2.3 times greater probabilities to have established periodontal disease than non‐smokers, independent of age, sex and plaque index, however,

999-548: A given offgas temperature, the NOx level is lowest when excess oxygen is kept lowest. Adherence to these two principles is furthered by making material and heat balances on the combustion process. The material balance directly relates the air/fuel ratio to the percentage of O 2 in the combustion gas. The heat balance relates the heat available for the charge to the overall net heat produced by fuel combustion. Additional material and heat balances can be made to quantify

1110-463: A hydroperoxide radical (HOO). This reacts further to give hydroperoxides, which break up to give hydroxyl radicals . There are a great variety of these processes that produce fuel radicals and oxidizing radicals. Oxidizing species include singlet oxygen, hydroxyl, monatomic oxygen, and hydroperoxyl . Such intermediates are short-lived and cannot be isolated. However, non-radical intermediates are stable and are produced in incomplete combustion. An example

1221-413: A mixture of aerosol particles that includes the pharmacologically active alkaloid nicotine , which stimulates the nicotinic acetylcholine receptors in the brain . Other notable active substances inhaled via smoking include tetrahydrocannabinol (from cannabis ), morphine (from opium ) and cocaine (from crack ). Smoking is one of the most common forms of recreational drug use . Tobacco smoking

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1332-562: A new type of social activity and a form of drug intake which previously had been unknown. Perception surrounding smoking has varied over time and from one place to another: holy and sinful, sophisticated and vulgar, a panacea and deadly health hazard. In the last decade of the 20th century, smoking came to be viewed in a decidedly negative light, especially in Western countries. The history of smoking dates back to as early as 5000 BCE for shamanistic rituals. Many ancient civilizations, such as

1443-406: A result of smoking. The risk of dying from lung cancer before age 85 is 22.1% for a male smoker and 11.9% for a female current smoker, in the absence of competing causes of death. The corresponding estimates for lifelong nonsmokers are a 1.1% probability of dying from lung cancer before age 85 for a man of European descent, and a 0.8% probability for a woman. Smoking just one cigarette a day results in

1554-409: A risk of coronary heart disease that is halfway between that of a heavy smoker and a non-smoker. The non-linear dose–response relationship may be explained by smoking's effect on platelet aggregation . Among the diseases that can be caused by smoking are vascular stenosis , lung cancer, heart attacks and chronic obstructive pulmonary disease (COPD). Smoking during pregnancy may cause ADHD to

1665-449: A robust economy caused many potential consumers to give up or fail to take up the habit. Recent years shows an increase in the consumption of vaporized heroin, methamphetamine and Phencyclidine (PCP). Along with a smaller number of psychedelic drugs such as Changa , DMT , 5-Meo-DMT , and Salvia divinorum . The most popular type of substance that is smoked is tobacco . There are many different tobacco cultivars which are made into

1776-411: A staunch anti-smoker and the author of A Counterblaste to Tobacco , tried to curb the new trend by enforcing a whopping 4000% tax increase on tobacco in 1604, it proved a failure, as London had some 7,000 tobacco sellers by the early 17th century. Later, scrupulous rulers would realise the futility of smoking bans and instead turned tobacco trade and cultivation into lucrative government monopolies. By

1887-414: A strong shock wave giving it its characteristic high-pressure peak and high detonation velocity . The act of combustion consists of three relatively distinct but overlapping phases: Efficient process heating requires recovery of the largest possible part of a fuel's heat of combustion into the material being processed. There are many avenues of loss in the operation of a heating process. Typically,

1998-428: A tightly rolled tube of paper, usually manufactured industrially and including a filter , or hand-rolled with loose tobacco. Other popular smoking tools are various pipes and cigars. A less common but increasingly popular alternative to smoking is vaporizers, which use hot air convection to deliver the substance without combustion, which may reduce health risks. A portable vaporization alternative appeared in 2003 with

2109-426: A very low probability. To initiate combustion, energy is required to force dioxygen into a spin-paired state, or singlet oxygen . This intermediate is extremely reactive. The energy is supplied as heat , and the reaction then produces additional heat, which allows it to continue. Combustion of hydrocarbons is thought to be initiated by hydrogen atom abstraction (not proton abstraction) from the fuel to oxygen, to give

2220-445: A vital role in stabilizing the flame in such combustion chambers . Generally, the chemical equation for stoichiometric combustion of a hydrocarbon in oxygen is: For example, the stoichiometric combustion of methane in oxygen is: If the stoichiometric combustion takes place using air as the oxygen source, the nitrogen present in the air ( Atmosphere of Earth ) can be added to the equation (although it does not react) to show

2331-536: A whole range of causes; vascular abnormalities such as stenosis , lung cancer, heart attacks, strokes, impotence , low birth weight of infants born by smoking mothers . 8% of long-term smokers develop the characteristic set of facial changes known to doctors as smoker's face . Tobacco smoke is a complex mixture of over 5,000 identified chemicals, of which 98 are known to have specific toxicological properties. The most important chemicals causing cancer are those that produce DNA damage since such damage appears to be

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2442-402: A wide variety of mixtures and brands. Tobacco is often sold flavored, often with various fruit aromas, something which is especially popular for use with water pipes, such as hookahs . The second most common substance that is smoked is cannabis , made from the flowers or leaves of Cannabis sativa or Cannabis indica . The substance is considered illegal in most countries in the world and in

2553-460: Is acetaldehyde produced in the combustion of ethanol . An intermediate in the combustion of carbon and hydrocarbons, carbon monoxide , is of special importance because it is a poisonous gas , but also economically useful for the production of syngas . Solid and heavy liquid fuels also undergo a great number of pyrolysis reactions that give more easily oxidized, gaseous fuels. These reactions are endothermic and require constant energy input from

2664-454: Is stoichiometric concerning the fuel, where there is no remaining fuel, and ideally, no residual oxidant. Thermodynamically, the chemical equilibrium of combustion in air is overwhelmingly on the side of the products. However, complete combustion is almost impossible to achieve, since the chemical equilibrium is not necessarily reached, or may contain unburnt products such as carbon monoxide , hydrogen and even carbon ( soot or ash). Thus,

2775-400: Is 'low' (i.e., 'micro' in the sense of 'small' and not necessarily a millionth of Earth's normal gravity) such that the influence of buoyancy on physical processes may be considered small relative to other flow processes that would be present at normal gravity. In such an environment, the thermal and flow transport dynamics can behave quite differently than in normal gravity conditions (e.g.,

2886-419: Is 1 / (1 + 2 + 7.54) = 9.49% vol. The stoichiometric combustion reaction for C α H β O γ in air: The stoichiometric combustion reaction for C α H β O γ S δ : The stoichiometric combustion reaction for C α H β O γ N δ S ε : The stoichiometric combustion reaction for C α H β O γ F δ : Various other substances begin to appear in significant amounts in combustion products when

2997-457: Is also sometimes regulated to make smoking less appealing. Despite the many bans, European countries still hold 18 of the top 20 spots, and according to the ERC, a market research company, the heaviest smokers are from Greece, averaging 3,000 cigarettes per person in 2007. Rates of smoking have leveled off or declined in the developed world but continue to rise in developing countries. Smoking rates in

3108-783: Is among the leading causes of many diseases such as lung cancer , heart attack , COPD , erectile dysfunction , and birth defects . Diseases related to tobacco smoking have been shown to kill approximately half of long-term smokers when compared to average mortality rates faced by non-smokers. Smoking caused over five million deaths a year from 1990 to 2015. Non-smokers account for 600,000 deaths globally due to second-hand smoke . The health hazards of smoking have caused many countries to institute high taxes on tobacco products, publish advertisements to discourage use, limit advertisements that promote use, and provide help with quitting for those who do smoke. Smoking can be dated to as early as 5000 BCE, and has been recorded in many different cultures across

3219-403: Is attracting public attention. In the early 1980s, organized international trafficking of cocaine grew. However, overproduction and tighter legal enforcement for the illegal product caused drug dealers to convert the powder to "crack" – a solid, smokable form of cocaine that could be sold in smaller quantities to more people. This trend abated in the 1990s as increased police action coupled with

3330-463: Is converted to carbon monoxide , and some of the hydrogens remain unreacted. A complete set of equations for the combustion of a hydrocarbon in the air, therefore, requires an additional calculation for the distribution of oxygen between the carbon and hydrogen in the fuel. The amount of air required for complete combustion is known as the "theoretical air" or "stoichiometric air". The amount of air above this value actually needed for optimal combustion

3441-581: Is greatly preferred especially as carbon monoxide is a poisonous gas. When breathed, carbon monoxide takes the place of oxygen and combines with some of the hemoglobin in the blood, rendering it unable to transport oxygen. These oxides combine with water and oxygen in the atmosphere, creating nitric acid and sulfuric acids , which return to Earth's surface as acid deposition, or "acid rain." Acid deposition harms aquatic organisms and kills trees. Due to its formation of certain nutrients that are less available to plants such as calcium and phosphorus, it reduces

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3552-532: Is harvested for diverse uses such as cooking , production of electricity or industrial or domestic heating. Combustion is also currently the only reaction used to power rockets . Combustion is also used to destroy ( incinerate ) waste, both nonhazardous and hazardous. Oxidants for combustion have high oxidation potential and include atmospheric or pure oxygen , chlorine , fluorine , chlorine trifluoride , nitrous oxide and nitric acid . For instance, hydrogen burns in chlorine to form hydrogen chloride with

3663-428: Is known as the "excess air", and can vary from 5% for a natural gas boiler, to 40% for anthracite coal, to 300% for a gas turbine . Incomplete combustion will occur when there is not enough oxygen to allow the fuel to react completely to produce carbon dioxide and water. It also happens when the combustion is quenched by a heat sink, such as a solid surface or flame trap. As is the case with complete combustion, water

3774-625: Is one of the leading preventable causes of deaths globally and is the cause of over 8 million deaths annually, 1.2 million of which are non-smokers who die due to second-hand smoke . In the United States, about 500,000 deaths per year are attributed to smoking-related diseases and a recent study estimated that as much as one-third of China's male population will have significantly shortened lifespans due to smoking. Male and female smokers lose an average of 13.2 and 14.5 years of life, respectively. At least half of all lifelong smokers die earlier as

3885-438: Is positively correlated with the risk of heart disease. People who survive severe carbon monoxide poisoning may suffer long-term health problems. Carbon monoxide from the air is absorbed in the lungs which then binds with hemoglobin in human's red blood cells. This reduces the capacity of red blood cells that carry oxygen throughout the body. Smoldering is the slow, low-temperature, flameless form of combustion, sustained by

3996-548: Is produced by incomplete combustion; however, carbon and carbon monoxide are produced instead of carbon dioxide. For most fuels, such as diesel oil, coal, or wood, pyrolysis occurs before combustion. In incomplete combustion, products of pyrolysis remain unburnt and contaminate the smoke with noxious particulate matter and gases. Partially oxidized compounds are also a concern; partial oxidation of ethanol can produce harmful acetaldehyde , and carbon can produce toxic carbon monoxide. The designs of combustion devices can improve

4107-725: Is the most popular form, being practised by over one billion people globally, of whom the majority are in the developing countries . Less common drugs for smoking include cannabis and opium . Some of the substances are classified as hard narcotics , like heroin , but the use of these is very limited as they are usually not commercially available. Cigarettes are primarily industrially manufactured but also can be hand-rolled from loose tobacco and rolling paper . Other smoking implements include pipes , cigars , bidis , hookahs , and bongs. Smoking has negative health effects , because smoke inhalation inherently poses challenges to various physiologic processes such as respiration . Smoking tobacco

4218-417: Is the source of oxygen ( O 2 ). In the air, each mole of oxygen is mixed with approximately 3.71  mol of nitrogen. Nitrogen does not take part in combustion, but at high temperatures, some nitrogen will be converted to NO x (mostly NO , with much smaller amounts of NO 2 ). On the other hand, when there is insufficient oxygen to combust the fuel completely, some fuel carbon

4329-510: Is the vapor that burns, not the liquid. Therefore, a liquid will normally catch fire only above a certain temperature: its flash point . The flash point of liquid fuel is the lowest temperature at which it can form an ignitable mix with air. It is the minimum temperature at which there is enough evaporated fuel in the air to start combustion. Combustion of gaseous fuels may occur through one of four distinctive types of burning: diffusion flame , premixed flame , autoignitive reaction front , or as

4440-648: Is theoretically needed to ensure that all the fuel burns. For methane ( CH 4 ) combustion, for example, slightly more than two molecules of oxygen are required. The second principle of combustion management, however, is to not use too much oxygen. The correct amount of oxygen requires three types of measurement: first, active control of air and fuel flow; second, offgas oxygen measurement; and third, measurement of offgas combustibles. For each heating process, there exists an optimum condition of minimal offgas heat loss with acceptable levels of combustibles concentration. Minimizing excess oxygen pays an additional benefit: for

4551-408: Is to discourage smoking among minors and many states have passed laws against selling tobacco products to underage customers (establishing a smoking age ). Many developing countries have not adopted anti-smoking policies, leading some to call for anti-smoking campaigns and further education to explain the negative effects of ETS (Environmental Tobacco Smoke) in developing countries. Tobacco advertising

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4662-643: The American Civil War in the 1860s, from which the primary labor force transition from slavery to sharecropping . This compounded with a change in demand, lead to the industrialization of tobacco production with the cigarette. James Albert Bonsack , a craftsman, in 1881 produced a machine to speed the production of cigarettes. In the 19th century, the practise of smoking opium became widespread in China . Previously, opium had only been ingested via consumption, and then only for its medicinal properties (opium

4773-629: The Great Depression , Adolf Hitler condemned his earlier smoking habit as a waste of money, and later with stronger assertions. This movement was further strengthened with Nazi reproductive policy as women who smoked were viewed as unsuitable to be wives and mothers in a German family. The movement in Nazi Germany did reach across enemy lines during the Second World War, as anti-smoking groups quickly lost popular support. By

4884-684: The Ming dynasty . Later, the Manchu rulers of the Qing dynasty , would proclaim smoking "a more heinous crime than that even of neglecting archery". In Edo period Japan, some of the earliest tobacco plantations were scorned by the shōgun as being a threat to the military economy by letting valuable farmland go to waste for the use of a recreational drug instead of being used to plant food crops. Religious leaders have often been prominent among those who considered smoking immoral or outright blasphemous. In 1634,

4995-460: The Patriarch of Moscow and all Rus' forbade the sale of tobacco and sentenced men and women who flouted the ban to have their nostrils slit and their backs whipped until skin came off their backs. The Western church leader Pope Urban VII likewise condemned smoking in a papal bull of 1590. Despite many concerted efforts, restrictions and bans were almost universally ignored. When James VI and I ,

5106-513: The developing countries , however, tobacco consumption continues to rise at 3.4% in 2002. In Africa, smoking is in most areas considered to be modern, and many of the strong adverse opinions that prevail in the West receive much less attention. Today Russia leads as the top consumer of tobacco followed by Indonesia , Laos , Ukraine , Belarus , Greece , Jordan , and China . At the global scale, initial ideas of an international convention towards

5217-457: The efficiency of a burner during the combustion process. Also, the efficiency of an internal combustion engine can be measured in this way, and some U.S. states and local municipalities use combustion analysis to define and rate the efficiency of vehicles on the road today. Carbon monoxide is one of the products from incomplete combustion . The formation of carbon monoxide produces less heat than formation of carbon dioxide so complete combustion

5328-410: The flame temperature is above about 1600  K . When excess air is used, nitrogen may oxidize to NO and, to a much lesser extent, to NO 2 . CO forms by disproportionation of CO 2 , and H 2 and OH form by disproportionation of H 2 O . For example, when 1  mol of propane is burned with 28.6  mol of air (120% of the stoichiometric amount),

5439-446: The heat-treatment of metals and for gas carburizing . The general reaction equation for incomplete combustion of one mole of a hydrocarbon in oxygen is: When z falls below roughly 50% of the stoichiometric value, CH 4 can become an important combustion product; when z falls below roughly 35% of the stoichiometric value, elemental carbon may become stable. The products of incomplete combustion can be calculated with

5550-496: The opiates (including heroin and morphine ). Smoking is a risk factor in Alzheimer's disease . While smoking more than 15 cigarettes per day has been shown to worsen the symptoms of Crohn's disease , smoking has been shown to actually lower the prevalence of ulcerative colitis . Smokers are 30-40% more likely to develop type 2 diabetes than non-smokers, and the risk increases with the number of cigarettes smoked. Inhaling

5661-519: The 1650s. Soon after its introduction to the Old World , tobacco came under frequent criticism from state and religious leaders. Murad IV , sultan of the Ottoman Empire 1623–40 was among the first to attempt a smoking ban by claiming it was a threat to public morality and health. The Chongzhen Emperor of China issued an edict banning smoking two years before his death and the overthrow of

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5772-415: The 1920s, adverse health effects began to become more prevalent. In Germany, anti-smoking groups, often associated with anti-liquor groups, first published advocacy against the consumption of tobacco in the journal Der Tabakgegner (The Tobacco Opponent) in 1912 and 1932. In 1929, Fritz Lickint of Dresden, Germany, published a paper containing formal statistical evidence of a lung cancer–tobacco link. During

5883-548: The Babylonian and Chinese, burnt incense as a part of religious rituals, as did the Israelites and the later Catholic and Orthodox Christian churches. Smoking in the Americas probably had its origins in the incense-burning ceremonies of shamans but was later adopted for pleasure, or as a social tool. The smoking of tobacco, as well as various hallucinogenic drugs, was used to achieve trances and to come into contact with

5994-812: The First and Second Opium Wars resulted in the legalization of the importation of opium into China. Opium smoking later spread with Chinese immigrants and spawned many infamous opium dens in Chinatowns around South and Southeast Asia, Europe and the Americas. In the latter half of the 19th century, opium smoking became popular in the artistic community in Europe, especially Paris; artists' neighborhoods such as Montparnasse and Montmartre became virtual "opium capitals". While opium dens that catered primarily to emigrant Chinese continued to exist in Chinatowns around

6105-462: The United States and European Union enforce limits to vehicle nitrogen oxide emissions, which necessitate the use of special catalytic converters or treatment of the exhaust with urea (see Diesel exhaust fluid ). The incomplete (partial) combustion of a hydrocarbon with oxygen produces a gas mixture containing mainly CO 2 , CO , H 2 O , and H 2 . Such gas mixtures are commonly prepared for use as protective atmospheres for

6216-524: The United States have dropped by half from 1965 to 2006, falling from 42% to 20.8% in adults. The effects of addiction on society vary considerably between different substances that can be smoked and the indirect social problems that they cause, in great part because of the differences in legislation and the enforcement of narcotics legislation around the world. Though nicotine is a highly addictive drug, its effects on cognition are not as intense or noticeable as other drugs such as cocaine, amphetamines or any of

6327-400: The actual habit is a function of operant conditioning . During the early stages, smoking provides pleasurable sensations (because of its action on the dopamine system) and thus serves as a source of positive reinforcement . After an individual has smoked for many years, the avoidance of withdrawal symptoms and negative reinforcement become the key motivations. Like all addictive substances,

6438-513: The adverse health effects were previously unknown or lacked substantial credibility. Health authorities sided with these claims up until 1998, from which they reversed their position. The Tobacco Master Settlement Agreement , originally between the four largest US tobacco companies and the Attorneys General of 46 states, restricted certain types of tobacco advertisement and required payments for health compensation; which later amounted to

6549-424: The aid of a material balance , together with the assumption that the combustion products reach equilibrium . For example, in the combustion of one mole of propane ( C 3 H 8 ) with four moles of O 2 , seven moles of combustion gas are formed, and z is 80% of the stoichiometric value. The three elemental balance equations are: These three equations are insufficient in themselves to calculate

6660-441: The amount of exposure required to become dependent on nicotine can vary from person to person. Combustion Combustion is often a complicated sequence of elementary radical reactions . Solid fuels , such as wood and coal , first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies the heat required to produce more of them. Combustion is often hot enough that incandescent light in

6771-542: The apparent relaxant effect of smoking only reflects the reversal of the tension and irritability that develop during nicotine depletion. Dependent smokers need nicotine to remain feeling normal. In the mid-20th century psychologists such as Hans Eysenck developed a personality profile for the typical smoker of that period; extraversion was associated with smoking, and smokers tended to be sociable, impulsive, risk taking, and excitement-seeking individuals. Although personality and social factors may make people likely to smoke,

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6882-418: The application of heat. Organic materials undergoing bacterial composting can generate enough heat to reach the point of combustion. Combustion resulting in a turbulent flame is the most used for industrial applications (e.g. gas turbines , gasoline engines , etc.) because the turbulence helps the mixing process between the fuel and oxidizer . The term 'micro' gravity refers to a gravitational state that

6993-496: The area of a tennis court). This can be used to administer useful medical as well as recreational drugs such as aerosols, consisting of tiny droplets of a medication, or as gas produced by burning plant material with a psychoactive substance or pure forms of the substance itself. Not all drugs can be smoked, for example the sulphate derivative that is most commonly inhaled through the nose, though purer free base forms of substances can, but often require considerable skill in administering

7104-408: The combustion gas composition. However, at the equilibrium position, the water-gas shift reaction gives another equation: For example, at 1200  K the value of K eq is 0.728. Solving, the combustion gas consists of 42.4% H 2 O , 29.0% CO 2 , 14.7% H 2 , and 13.9% CO . Carbon becomes a stable phase at 1200  K and 1  atm pressure when z is less than 30% of

7215-457: The combustion products contain 3.3% O 2 . At 1400  K , the equilibrium combustion products contain 0.03% NO and 0.002% OH . At 1800  K , the combustion products contain 0.17% NO , 0.05% OH , 0.01% CO , and 0.004% H 2 . Diesel engines are run with an excess of oxygen to combust small particles that tend to form with only a stoichiometric amount of oxygen, necessarily producing nitrogen oxide emissions. Both

7326-963: The countries that tolerate public consumption, it is sometimes only pseudo-legal. Despite this, a considerable percentage of the adult population in many countries have tried it with smaller minorities doing it on a regular basis. Since cannabis is illegal or only tolerated in many jurisdictions, there is no industrial mass-production of cigarettes, meaning that the most common form of smoking is with hand-rolled cigarettes (often called joints ) or with pipes. Water pipes are also fairly common; water pipes used for cannabis include designs known as bongs and bubblers, among others. A few other recreational drugs are smoked by smaller minorities. Most of these substances are controlled , and some are considerably more intoxicating than either tobacco or cannabis. These include crack cocaine , heroin, methamphetamine and PCP . A small number of psychedelic drugs are also smoked, including DMT , 5-Meo-DMT , and Salvia divinorum . Even

7437-400: The dominant loss is sensible heat leaving with the offgas (i.e., the flue gas ). The temperature and quantity of offgas indicates its heat content ( enthalpy ), so keeping its quantity low minimizes heat loss. In a perfect furnace, the combustion air flow would be matched to the fuel flow to give each fuel molecule the exact amount of oxygen needed to cause complete combustion. However, in

7548-440: The drug properly. The method is also somewhat inefficient since not all of the smoke will be inhaled. The inhaled substances trigger chemical reactions in nerve endings in the brain due to being similar to naturally occurring substances such as endorphins and dopamine , which are associated with sensations of pleasure. The result is what is usually referred to as a "high" that ranges between the mild stimulus caused by nicotine to

7659-401: The effect of tobacco on periodontal tissues seems to be more pronounced in men than in women. Studies have found that smokers had greater odds for more severe dental bone loss compared to non‐smokers; also, people who smoke and drink alcohol heavily have much higher risk of developing oral cancer (mouth and lip) compared with people who do neither. Smoking can also cause milanosis in

7770-638: The end of the 20th century, anti-smoking campaigns in Germany were unable to exceed the effectiveness of the Nazi-era climax in the years 1939–41 and German tobacco health research was described by Robert N. Proctor as "muted". In the UK and the US, an increase in lung cancer rates, formerly "among the rarest forms of disease", was noted by the 1930s, but its cause remained unknown and even the credibility of this increase

7881-638: The end of the Second World War, American cigarette manufacturers quickly reentered the German black market. Illegal smuggling of tobacco became prevalent, and leaders of the Nazi anti-smoking campaign were assassinated. As part of the Marshall Plan , the United States shipped free tobacco to Germany; with 24,000 tons in 1948 and 69,000 tons in 1949. Per capita yearly cigarette consumption in post-war Germany steadily rose from 460 in 1950 to 1,523 in 1963. By

7992-638: The existence of pipes to smoke opium in Cyprus and Crete as soon as the Bronze Age . Cannabis smoking was common in the Middle East before the arrival of tobacco, and was early on a common social activity that centered around the type of water pipe called a hookah . Smoking, especially after the introduction of tobacco, was an essential component of Muslim society and culture and became integrated with important traditions such as weddings, funerals and

8103-431: The form of either glowing or a flame is produced. A simple example can be seen in the combustion of hydrogen and oxygen into water vapor , a reaction which is commonly used to fuel rocket engines . This reaction releases 242   kJ/mol of heat and reduces the enthalpy accordingly (at constant temperature and pressure): Uncatalyzed combustion in air requires relatively high temperatures. Complete combustion

8214-408: The harmful long-term effects of smoking. Passive smoking , or secondhand smoking, which affects people in the immediate vicinity of smokers, is a major reason for the enforcement of smoking bans . These are laws enforced to stop individuals from smoking in indoor public places, such as bars, pubs and restaurants, thus reducing nonsmokers' exposure to secondhand smoke. A common concern among legislators

8325-486: The heat evolved when oxygen directly attacks the surface of a condensed-phase fuel. It is a typically incomplete combustion reaction. Solid materials that can sustain a smoldering reaction include coal, cellulose , wood , cotton , tobacco , peat , duff , humus , synthetic foams, charring polymers (including polyurethane foam ) and dust . Common examples of smoldering phenomena are the initiation of residential fires on upholstered furniture by weak heat sources (e.g.,

8436-479: The intense euphoria caused by heroin, cocaine and methamphetamines . Inhaling smoke into the lungs, no matter the substance, has adverse effects on one's health. The incomplete combustion produced by burning plant material, like tobacco or cannabis, produces carbon monoxide , which impairs the ability of blood to carry oxygen when inhaled into the lungs. There are several other toxic compounds in tobacco that constitute serious health hazards to long-term smokers from

8547-702: The introduction of electronic cigarettes , battery-operated, cigarette-shaped devices which produce an aerosol intended to mimic the smoke from burning tobacco, delivering nicotine to the user without some of the harmful substances released in tobacco smoke. Other than actual smoking equipment, many other items are associated with smoking; cigarette cases , cigar boxes , lighters , matchboxes , cigarette holders , cigar holders, ashtrays , silent butlers , pipe cleaners , tobacco cutters, match stands, pipe tampers, cigarette companions and so on. Some examples of these have become valuable collector items and particularly ornate and antique items can fetch high prices. Smoking

8658-627: The largest civil settlement in United States history. From 1965 to 2006, rates of smoking in the United States have declined from 42% to 20.8%. A significant majority of those who quit were professional, affluent men. Despite this decrease in the prevalence of consumption, the average number of cigarettes consumed per person per day increased from 22 in 1954 to 30 in 1978. This paradoxical event suggests that those who quit smoked less, while those who continued to smoke moved to smoke more light cigarettes. This trend has been paralleled by many industrialized nations as rates have either leveled-off or declined. In

8769-402: The liberation of heat and light characteristic of combustion. Although usually not catalyzed, combustion can be catalyzed by platinum or vanadium , as in the contact process . In complete combustion, the reactant burns in oxygen and produces a limited number of products. When a hydrocarbon burns in oxygen, the reaction will primarily yield carbon dioxide and water. When elements are burned,

8880-533: The link, based on which the government issued advice that smoking and lung cancer rates were related. In 1964 the United States Surgeon General 's Report on Smoking and Health demonstrated the relationship between smoking and cancer. Further reports confirmed this link in the 1980s and concluded in 1986 that passive smoking was also harmful. As scientific evidence mounted in the 1980s, tobacco companies claimed contributory negligence as

8991-420: The maximum degree of oxidation, and it can be temperature-dependent. For example, sulfur trioxide is not produced quantitatively by the combustion of sulfur. NO x species appear in significant amounts above about 2,800 °F (1,540 °C), and more is produced at higher temperatures. The amount of NO x is also a function of oxygen excess. In most industrial applications and in fires , air

9102-402: The mid-17th century every major civilization had been introduced to tobacco smoking and in many cases had already assimilated it into its culture, despite the attempts of many rulers to stamp the practice out with harsh penalties or fines. Tobacco, both product, and plant followed the major trade routes to major ports and markets, and then on into the hinterlands. The English language term smoking

9213-403: The most primitive form of smoking requires tools of some sort to perform. This has resulted in a staggering variety of smoking tools and paraphernalia from all over the world. Whether tobacco, cannabis, opium or herbs, some form of receptacle is required along with a source of fire to light the mixture. The most common today is by far the cigarette, consisting of a mild inhalant strain of tobacco in

9324-483: The mouth. Smoking has been also associated with oral conditions including dental caries , dental implant failures , premalignant lesions , and cancer . Smoking can affect the immune-inflammatory processes which may increase susceptibility to infections; it can alter the oral mycobiota and facilitate colonization of the oral cavity with fungi and pathogenic molds. Many governments are trying to deter people from smoking with anti-smoking campaigns in mass media stressing

9435-709: The prevention of tobacco had been initiated in the World Health Assembly (WHA) in 1996. In 1998, along with the successful election of Dr. Gro Harlem Brundtland as the Director-General, the World Health Organization set tobacco control as its leading health concern and has begun a program known as the Tobacco Free Initiative (TFI) in order to reduce rates of consumption in the developing world. However, it

9546-698: The primary labor force up until Bacon's Rebellion , from which the focus turned to slavery . This trend abated following the American Revolution as slavery became regarded as unprofitable. However the practice was revived in 1794 with the invention of the cotton gin. A Frenchman named Jean Nicot (from whose name the word nicotine is derived) introduced tobacco to France in 1560. From France tobacco spread to England. The first report documents an English sailor in Bristol in 1556, seen "emitting smoke from his nostrils". Like tea, coffee and opium, tobacco

9657-868: The primary underlying cause of cancer. Cunningham et al. combined the microgram weight of the compound in the smoke of one cigarette with the known genotoxic effect per microgram to identify the most carcinogenic compounds in cigarette smoke. The seven most important carcinogens in tobacco smoke are shown in the table, along with DNA alterations they cause. Most tobacco smokers begin during adolescence or early adulthood. Smoking has elements of risk-taking and rebellion, which often appeal to young people. The presence of high-status models and peers may also encourage smoking. Because teenagers are influenced more by their peers than by adults, attempts by parents, schools, and health professionals at preventing people from trying cigarettes are not always successful. Smokers often report that cigarettes help relieve feelings of stress. However,

9768-576: The produced smoke is usually toxic and contains unburned or partially oxidized products. Any combustion at high temperatures in atmospheric air , which is 78 percent nitrogen , will also create small amounts of several nitrogen oxides , commonly referred to as NOx , since the combustion of nitrogen is thermodynamically favored at high, but not low temperatures. Since burning is rarely clean, fuel gas cleaning or catalytic converters may be required by law. Fires occur naturally, ignited by lightning strikes or by volcanic products. Combustion ( fire )

9879-463: The productivity of the ecosystem and farms. An additional problem associated with nitrogen oxides is that they, along with hydrocarbon pollutants, contribute to the formation of ground level ozone , a major component of smog. Breathing carbon monoxide causes headache, dizziness, vomiting, and nausea. If carbon monoxide levels are high enough, humans become unconscious or die. Exposure to moderate and high levels of carbon monoxide over long periods

9990-425: The products are primarily the most common oxides. Carbon will yield carbon dioxide , sulfur will yield sulfur dioxide , and iron will yield iron(III) oxide . Nitrogen is not considered to be a combustible substance when oxygen is the oxidant . Still, small amounts of various nitrogen oxides (commonly designated NO x species) form when the air is the oxidative. Combustion is not necessarily favorable to

10101-644: The quality of combustion, such as burners and internal combustion engines . Further improvements are achievable by catalytic after-burning devices (such as catalytic converters ) or by the simple partial return of the exhaust gases into the combustion process. Such devices are required by environmental legislation for cars in most countries. They may be necessary to enable large combustion devices, such as thermal power stations , to reach legal emission standards . The degree of combustion can be measured and analyzed with test equipment. HVAC contractors, firefighters and engineers use combustion analyzers to test

10212-422: The real world, combustion does not proceed in a perfect manner. Unburned fuel (usually CO and H 2 ) discharged from the system represents a heating value loss (as well as a safety hazard). Since combustibles are undesirable in the offgas, while the presence of unreacted oxygen there presents minimal safety and environmental concerns, the first principle of combustion management is to provide more oxygen than

10323-442: The reinforcement of tobacco taxes and the implementation of smoke-free laws in 128 countries that led to the decrease of smoking prevalence in developing nations. In Nepal, "Smokers are not selfish", a health campaign lasting two weeks is started on the occasion of Valentine day and Vasant panchami to motiviate individuals to quit smoking as a sacrifice for their loved ones and making it a meaningful decision of life. This campaign

10434-667: The spirit world. Substances such as cannabis , clarified butter ( ghee ), fish offal, dried snake skins and various pastes molded around incense sticks dates back at least 2000 years. Fumigation ( dhupa ) and fire offerings ( homa ) are prescribed in the Ayurveda for medical purposes, and have been practiced for at least 3,000 years while smoking, dhumrapana (literally "drinking smoke"), has been practiced for at least 2,000 years. Before modern times these substances have been consumed through pipes , with stems of various lengths or chillums . Archaeological findings also show

10545-499: The stoichiometric composition of the fuel in air and the composition of the resultant flue gas. Treating all non-oxygen components in air as nitrogen gives a 'nitrogen' to oxygen ratio of 3.77, i.e. (100% − O 2 %) / O 2 % where O 2 % is 20.95% vol: where z = x + y 4 {\displaystyle z=x+{y \over 4}} . For example, the stoichiometric combustion of methane in air is: The stoichiometric composition of methane in air

10656-414: The stoichiometric value, at which point the combustion products contain more than 98% H 2 and CO and about 0.5% CH 4 . Substances or materials which undergo combustion are called fuels . The most common examples are natural gas, propane, kerosene , diesel , petrol, charcoal, coal, wood, etc. Combustion of a liquid fuel in an oxidizing atmosphere actually happens in the gas phase. It

10767-466: The stress levels of adult smokers are slightly higher than those of nonsmokers. Adolescent smokers report increasing levels of stress as they develop regular patterns of smoking, and smoking cessation leads to reduced stress. Far from acting as an aid for mood control, nicotine dependency seems to exacerbate stress. This is confirmed in the daily mood patterns described by smokers, with normal moods during smoking and worsening moods between cigarettes. Thus,

10878-404: The thermal advantage from preheating the combustion air, or enriching it in oxygen. Combustion in oxygen is a chain reaction in which many distinct radical intermediates participate. The high energy required for initiation is explained by the unusual structure of the dioxygen molecule. The lowest-energy configuration of the dioxygen molecule is a stable, relatively unreactive diradical in

10989-586: The time (for example, benzo[a]pyrene was isolated from coal tar and demonstrated to be a potent carcinogen in 1933), none were known to be contained in adequate quantities in tobacco smoke . Richard Doll in 1950 published research in the British Medical Journal showing a close link between smoking and lung cancer. Four years later, in 1954 the British Doctors Study , a study of some 40 thousand doctors over 20 years, confirmed

11100-416: The vaporized gas form of substances into the lungs is a quick and very effective way of delivering drugs into the bloodstream (as the gas diffuses directly into the pulmonary vein, then into the heart and from there to the brain) and affects the user within less than a second of the first inhalation. The lungs consist of several million tiny bulbs called alveoli that altogether have an area of over 70 m (about

11211-735: The world, the trend among the European artists largely abated after the outbreak of World War I. The consumption of Opium abated in China during the Cultural Revolution in the 1960s and 1970s. Many people have been critical about tobacco use since it gained popularity. In 1798, Dr. Benjamin Rush (early American physician, signer of the Declaration of Independence , Surgeon General under George Washington , and anti-tobacco activist)

11322-503: The world. Early smoking evolved in association with religious ceremonies; as offerings to deities; in cleansing rituals; or to allow shamans and priests to alter their minds for purposes of divination or spiritual enlightenment. After the European exploration and conquest of the Americas, the practice of smoking tobacco quickly spread to the rest of the world. In regions like India and Sub-Saharan Africa, it merged with existing practices of smoking (mostly of cannabis). In Europe, it introduced

11433-418: Was "against the habitual use of tobacco" because he believed it (a) "led to a desire for strong drink," (b) "was injurious both to health and morals," (c) "is generally offensive to" nonsmokers, (d) "produces a want of respect for" nonsmokers, and (e) "always disposes to unkind and unjust behavior towards them." With the modernization of cigarette production compounded with the increased life expectancies during

11544-587: Was an anaesthetic ). The narcotic was also outlawed in China sometime in the early 18th century due the societal issues it caused. Due to a massive trade imbalance, however, foreign merchants started to smuggle opium into China via Canton , to the chagrin of the Chinese authorities. Attempts by Chinese official Lin Zexu to eliminate the trade led to the outbreak of the First Opium War . The Chinese defeat in

11655-674: Was coined in the late 18th century; before then the practice was referred to as drinking smoke . Tobacco and cannabis were used in Sub-Saharan Africa, much like elsewhere in the world, to confirm social relations, but also created entirely new ones. In what is today Congo , a society called Bena Diemba ("People of Cannabis") was organized in the late 19th century in Lubuko ("The Land of Friendship"). The Bena Diemba were collectivist pacifists that rejected alcohol and herbal medicines in favor of cannabis. The growth remained stable until

11766-459: Was expressed in architecture, clothing, literature and poetry. Cannabis smoking was introduced to Sub-Saharan Africa through Ethiopia and the east African coast by either Indian or Arab traders in the 13th century or earlier and spread on the same trade routes as those that carried coffee, which originated in the highlands of Ethiopia. It was smoked in calabash water pipes with terracotta smoking bowls, apparently an Ethiopian invention which

11877-482: Was just one of many intoxicants that was originally used as a form of medicine. Tobacco was introduced around 1600 by French merchants in what today is modern-day The Gambia and Senegal . At the same time caravans from Morocco brought tobacco to the areas around Timbuktu and the Portuguese brought the commodity (and the plant) to southern Africa, establishing the popularity of tobacco throughout all of Africa by

11988-441: Was later conveyed to eastern, southern and central Africa. Reports from the first European explorers and conquistadors to reach the Americas tell of rituals where native priests smoked themselves into such high degrees of intoxication that it is unlikely that the rituals were limited to just tobacco. In 1612, six years after the settlement of Jamestown , John Rolfe was credited as the first settler to successfully grow tobacco as

12099-555: Was not until 2003 that the Framework Convention on Tobacco Control (FCTC) was accepted in WHA and entered into force in 2005. FCTC marked a milestone as the first international treaty concerning a global health issue that aims to combat tobacco in multiple aspects including tobacco taxes, advertisement, trading, environmental affects, health influences, etc. The birth of this evidence-based and systematic approach has resulted in

12210-527: Was sometimes disputed as late as 1950. For example, in Connecticut, reported age-adjusted incidence rates of lung cancer among males increased 220% between 1935–39 and 1950–54. In the UK, the share of lung cancer among all cancer deaths in men increased from 1.5% in 1920 to 19.7% in 1947. Nevertheless, these increases were questioned as potentially caused by increased reporting and improved methods of diagnosis. Although several carcinogens were already known at

12321-456: Was the first controlled chemical reaction discovered by humans, in the form of campfires and bonfires , and continues to be the main method to produce energy for humanity. Usually, the fuel is carbon , hydrocarbons , or more complicated mixtures such as wood that contain partially oxidized hydrocarbons. The thermal energy produced from the combustion of either fossil fuels such as coal or oil , or from renewable fuels such as firewood ,

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