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103-401: As is the case for many other explosives, nitroglycerin becomes more and more prone to exploding (i.e. spontaneous decomposition ) as the temperature is increased. Upon heating to 218 °C or over under atmospheric pressure , nitroglycerin becomes extremely unstable and tends to explode. When placed in vacuum, it has an autoignition temperature of 270 °C instead. With a melting point of 12.8 °C,

206-684: A Wells Fargo company office in San Francisco and killing 15 people. This led to a complete ban on the transportation of liquid nitroglycerin in California. The on-site manufacture of nitroglycerin was thus required for the remaining hard-rock drilling and blasting required for the completion of the First transcontinental railroad in North America. On Christmas Day 1867, an attempt to dispose of nine canisters of Blasting Oil that had been illegally stored at

309-549: A skeleton varies greatly. Even when a body is decomposed, embalming treatment can still be achieved (the arterial system decays more slowly) but would not restore a natural appearance without extensive reconstruction and cosmetic work, and is largely used to control the foul odors due to decomposition. An animal can be preserved almost perfectly, for millions of years in a resin such as amber . There are some examples where bodies have been inexplicably preserved (with no human intervention) for decades or centuries and appear almost

412-455: A tolerance to and dependence on nitroglycerin after long-term exposure. Although rare, withdrawal can be fatal;symptoms include chest pain and other heart problems. These symptoms may be relieved with re-exposure to nitroglycerin or other suitable organic nitrates. For workers in nitroglycerin (NTG) manufacturing facilities, the effects of withdrawal sometimes include "Sunday heart attacks" in those experiencing regular nitroglycerin exposure in

515-410: A desensitizer. When nitroglycerin explodes, the products after cooling are given by: The heat released can be calculated from the heats of formation. Using −371 kJ/ mol for the heat of formation of condensed phase nitroglycerin gives 1414 kJ/mol released if forming water vapor, and 1524 if forming liquid water. The detonation velocity of nitroglycerin is 7820 meters per second, which

618-405: A fast rate but cold enough to avoid runaway reaction. The nitrator vessel, often constructed of iron or lead and generally stirred with compressed air , has an emergency trap door at its base, which hangs over a large pool of very cold water and into which the whole reaction mixture (called the charge) can be dumped to prevent an explosion, a process referred to as drowning. If the temperature of

721-457: A higher proportion of recalcitrant material. Consequently, dead animals decompose more rapidly than dead leaves, which themselves decompose more rapidly than fallen branches. As organic material in the soil ages, its quality decreases. The more labile compounds decompose quickly, leaving an increasing proportion of recalcitrant material called humus . Microbial cell walls also contain recalcitrant materials like chitin , and these also accumulate as

824-468: A larger surface area that can hold water. The higher the water content of a soil, the lower the oxygen content and consequently, the lower the rate of decomposition. Clay minerals also bind particles of organic material to their surface, making them less accessible to microbes. Soil disturbance like tilling increases decomposition by increasing the amount of oxygen in the soil and by exposing new organic matter to soil microbes. The quality and quantity of

927-476: A later time. Aquatic and marine environments have break-down agents that include bacteria, fish, crustaceans, fly larvae and other carrion scavengers. Five general stages are typically used to describe the process of decomposition in vertebrate animals: fresh, bloat, active decay, advanced decay, and dry/remains. The general stages of decomposition are coupled with two stages of chemical decomposition: autolysis and putrefaction . These two stages contribute to

1030-403: A major role in breaking down matter, both directly and indirectly via a multitrophic cascading effect Following this, the plant detritus (consisting of cellulose , hemicellulose , microbial metabolites , and lignin ) undergoes chemical alteration by microbes. Different types of compounds decompose at different rates. This is dependent on their chemical structure . For instance, lignin

1133-433: A place where the body is buried in organic material and oxygen cannot reach it. This process of putrefaction has a bad odor accompanied by it due to the hydrogen sulfide and organic matter containing sulfur. Embalming is the practice of delaying the decomposition of human and animal remains. Embalming slows decomposition somewhat but does not forestall it indefinitely. Embalmers typically pay great attention to parts of

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1236-452: A process used to recover oil and gas from shale formations. The technique involves displacing and detonating nitroglycerin in natural or hydraulically induced fracture systems, or displacing and detonating nitroglycerin in hydraulically induced fractures followed by wellbore shots using pelletized TNT . Nitroglycerin has an advantage over some other high explosives that on detonation it produces practically no visible smoke. Therefore, it

1339-410: A rifle ball when in that condition but on the other hand it appears to be more liable to explode on breaking, crushing, tamping, etc." Frozen nitroglycerin is much less energetic than liquid, and so must be thawed before use. Thawing it out can be extremely sensitizing, especially if impurities are present or the warming is too rapid. Ethylene glycol dinitrate or another polynitrate may be added to lower

1442-536: A slower rate) even after soils become too dry to support plant growth. When the rains return and soils become wet, the osmotic gradient between the bacterial cells and the soil water causes the cells to gain water quickly. Under these conditions, many bacterial cells burst, releasing a pulse of nutrients. Decomposition rates also tend to be slower in acidic soils. Soils which are rich in clay minerals tend to have lower decomposition rates, and thus, higher levels of organic matter. The smaller particles of clay result in

1545-402: A smaller preload reduces the ventricular transmural pressure (pressure exerted on the walls of the heart), which decreases the compression of heart arteries to allow more blood to flow through the heart. At higher doses, it also dilates arteries, thereby reducing afterload (decreasing the pressure against which the heart must pump). An improved ratio of myocardial oxygen demand to supply leads to

1648-570: A specific explosive energy density of 1.488  kilocalories per gram, or 6.23 kJ/g, making nitroglycerin 49% more energetic on a mass basis than the standard definitional value assigned to TNT (precisely 1 kcal/g). Nitroglycerin can be produced by acid-catalyzed nitration of glycerol (glycerin). The industrial manufacturing process often reacts glycerol with a nearly 1:1 mixture of concentrated sulfuric acid and concentrated nitric acid . This can be produced by mixing white fuming nitric acid —a quite expensive pure nitric acid in which

1751-507: A substance by chemical or physical processes", e.g., hydrolysis ; the latter means "the metabolic breakdown of materials into simpler components by living organisms", typically by microorganisms. Decomposition begins at the moment of death, caused by two factors: autolysis , the breaking down of tissues by the body's own internal chemicals and enzymes , and putrefaction , the breakdown of tissues by bacteria . These processes release compounds such as cadaverine and putrescine , that are

1854-404: A sweet and burning taste when ingested. Unintentional detonation may ensue when dropped, shaken, lit on fire, rapidly heated, exposed to sunlight and ozone, subjected to sparks and electrical discharges, or roughly handled. Its sensitivity to exploding is responsible for numerous devastating industrial accidents throughout its history. The chemical's characteristic reactivity may be reduced through

1957-472: Is a component of wood, which is relatively resistant to decomposition and can in fact only be decomposed by certain fungi , such as the white-rot fungi. Wood decomposition is a complex process involving fungi which transport nutrients to the nutritionally scarce wood from outside environment. Because of this nutritional enrichment, the fauna of saproxylic insects may develop and, in turn, affect dead wood, contributing to decomposition and nutrient cycling in

2060-422: Is a positive sign, but it may take several years for the ecosystem to fully recover and return to its pre-disturbance state. All that remains of the cadaver at this stage is dry skin, cartilage , and bones , which will become dry and bleached if exposed to the elements. If all soft tissue is removed from the cadaver, it is referred to as completely skeletonized , but if only portions of the bones are exposed, it

2163-435: Is about 113% the speed of TNT . Accordingly, nitroglycerin is considered to be a high- brisance explosive, which is to say, it has excellent shattering ability. The heat liberated during detonation raises the temperature of the gaseous byproducts to about 5,000 °C (9,000 °F). With a standard enthalpy of explosive decomposition of −1414 kJ/ mol and a molecular weight of 227.0865 g/mol, nitroglycerin has

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2266-405: Is an important field of study within food science . Food decomposition can be slowed down by conservation . The spoilage of meat occurs, if the meat is untreated, in a matter of hours or days and results in the meat becoming unappetizing, poisonous or infectious. Spoilage is caused by the practically unavoidable infection and subsequent decomposition of meat by bacteria and fungi, which are borne by

2369-435: Is characterized by a decrease in the intensity of the disturbance and an increase in the amount of plant growth around the affected area. This is a sign that the nutrients and other ecological resources present in the surrounding soil have not yet returned to their normal levels. During this stage, it is important to monitor the ecosystem for any signs of continued disturbance or ecological stress. The resurgence of plant growth

2472-418: Is not uncommon for bodies to remain preserved to a viewable extent after decades. Notable viewable embalmed bodies include those of: A body buried in a sufficiently dry environment may be well preserved for decades. This was observed in the case for murdered civil rights activist Medgar Evers , who was found to be almost perfectly preserved over 30 years after his death, permitting an accurate autopsy when

2575-449: Is often known as a rock cut . Drilling and blasting currently utilizes many different varieties of explosives with different compositions and performance properties. Higher velocity explosives are used for relatively hard rock in order to shatter and break the rock, while low velocity explosives are used in soft rocks to generate more gas pressure and a greater heaving effect. For instance, an early 20th-century blasting manual compared

2678-413: Is one of the world's most powerful explosives, comparable to the more recently developed RDX and PETN . Early in its history, liquid nitroglycerin was found to be " desensitized " by freezing it at a temperature below 45 to 55 °F (7 to 13 °C) depending on its purity. Its sensitivity to shock while frozen is somewhat unpredictable: "It is more insensitive to the shock from a fulminate cap or

2781-478: Is physical breakup or fragmentation of the plant material into smaller pieces, providing greater surface area for colonization and attack by decomposers . In fallen dead parts of plants ( plant litter ), this process is largely carried out by saprophagous ( detritivorous ) soil invertebrate fauna, whereas in standing parts of plants, primarily parasitic life-forms such as parasitic plants (e.g. mistletoes ), insects (e.g. aphids ) and fungi (e.g. polypores ) play

2884-653: Is referred to as partially skeletonized. A dead body that has been exposed to the open elements, such as water and air, will decompose more quickly and attract much more insect activity than a body that is buried or confined in special protective gear or artifacts. This is due, in part, to the limited number of insects that can penetrate soil and the lower temperatures under the soil. The rate and manner of decomposition in an animal body are strongly affected by several factors. In roughly descending degrees of importance, they are: The speed at which decomposition occurs varies greatly. Factors such as temperature, humidity, and

2987-476: Is still used in the construction of tunnels, such as in the construction of the Lötschberg Base Tunnel . The decision whether to construct a tunnel using a TBM or using a drill and blast method includes a number of factors. Tunnel length is a key issue that needs to be addressed because large TBMs for a rock tunnel have a high capital cost, but because they are usually quicker than a drill and blast tunnel

3090-456: Is the body's accessibility to insects, particularly flies . On the surface in tropical areas, invertebrates alone can easily reduce a fully fleshed corpse to clean bones in under two weeks. The skeleton itself is not permanent; acids in soils can reduce it to unrecognizable components. This is one reason given for the lack of human remains found in the wreckage of the Titanic , even in parts of

3193-440: Is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide , water , simple sugars and mineral salts. The process is a part of the nutrient cycle and is essential for recycling the finite matter that occupies physical space in the biosphere . Bodies of living organisms begin to decompose shortly after death . Animals, such as earthworms , also help decompose

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3296-422: Is thus added as an ester C−O−NO 2 and water is produced. This is different from an electrophilic aromatic substitution reaction in which nitronium ions are the electrophile . The addition of glycerol results in an exothermic reaction (i.e., heat is produced), as usual for mixed-acid nitrations. If the mixture becomes too hot, it results in a runaway reaction, a state of accelerated nitration accompanied by

3399-528: Is useful as an ingredient in the formulation of various kinds of smokeless powder . Alfred Nobel then developed ballistite , by combining nitroglycerin and guncotton . He patented it in 1887. Ballistite was adopted by a number of European governments, as a military propellant. Italy was the first to adopt it. The British government and the Commonwealth governments adopted cordite instead, which had been developed by Sir Frederick Abel and Sir James Dewar of

3502-569: The Body Farm ) in Knoxville, Tennessee , has several bodies laid out in various situations in a fenced-in plot near the medical center. Scientists at the Body Farm study how the human body decays in various circumstances to gain a better understanding of decomposition. Decomposition of plant matter occurs in many stages. It begins with leaching by water; the most easily lost and soluble carbon compounds are liberated in this process. Another early process

3605-815: The Royal Navy Cordite Factory, Holton Heath , in Dorset , England. A large cordite factory was also built in Canada during World War I. The Canadian Explosives Limited cordite factory at Nobel, Ontario , was designed to produce 1,500,000 lb (680 t) of cordite per month, requiring about 286 tonnes of nitroglycerin per month. In its undiluted form, nitroglycerin is a contact explosive , with physical shock causing it to explode. If it has not been adequately purified during manufacture it can degrade over time to even more unstable forms. This makes nitroglycerin highly dangerous to transport or use. In its undiluted form, it

3708-414: The chemical process of decomposition , which breaks down the main components of the body. With death the microbiome of the living organism collapses and is followed by the necrobiome that undergoes predictable changes over time. Among those animals that have a heart, the fresh stage begins immediately after the heart stops beating. From the moment of death, the body begins cooling or warming to match

3811-595: The Krümmel factory were destroyed twice. In April 1866, several crates of nitroglycerin were shipped to California , three of which were destined for the Central Pacific Railroad , which planned to experiment with it as a blasting explosive to expedite the construction of the 1,659-foot-long (506 m) Summit Tunnel through the Sierra Nevada Mountains . One of the remaining crates exploded, destroying

3914-579: The Nobels' armaments factory in 1864 in Heleneborg , Sweden. One year later, Nobel founded Alfred Nobel and Company in Germany and built an isolated factory in the Krümmel hills of Geesthacht near Hamburg . This business exported a liquid combination of nitroglycerin and gunpowder called "Blasting Oil", but this was extremely unstable and difficult to handle, as evidenced in numerous catastrophes. The buildings of

4017-489: The Soviet Union was the leader in total volume with 2.7 billion kg of explosives consumed (13 m per capita), and Australia had the highest per capita explosives consumption that year with 45 m per capita. As the name suggests, drilling and blasting works as follows: The positions and depths of the holes (and the amount of explosive each hole receives) are determined by a carefully constructed pattern, which, together with

4120-1000: The United Kingdom in 1889. The original Cordite Mk I consisted of 58% nitroglycerin, 37% guncotton, and 5.0% petroleum jelly . Ballistite and cordite were both manufactured in the form of "cords". Smokeless powders were originally developed using nitrocellulose as the sole explosive ingredient. Therefore, they were known as single-base propellants. A range of smokeless powders that contains both nitrocellulose and nitroglycerin, known as double-base propellants, were also developed. Smokeless powders were originally supplied only for military use, but they were also soon developed for civilian use and were quickly adopted for sports. Some are known as sporting powders. Triple-base propellants contain nitrocellulose, nitroglycerin, and nitroguanidine , but are reserved mainly for extremely high-caliber ammunition rounds such as those used in tank cannons and naval artillery . Blasting gelatin, also known as gelignite ,

4223-562: The White Swan Inn in the centre of Newcastle upon Tyne resulted in an explosion on the Town Moor that killed eight people. In June 1869, two one-ton wagons loaded with nitroglycerin, then known locally as Powder-Oil, exploded in the road at the North Wales village of Cwm-y-glo . The explosion led to the loss of six lives, many injuries and much damage to the village. Little trace was found of

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4326-511: The addition of desensitizing agents, which makes it less likely to explode. Clay ( diatomaceous earth ) is an example of such an agent, forming dynamite, a much more easily handled composition. Addition of other desensitizing agents give birth to the various formulations of dynamite. Nitroglycerin has been used for over 130 years in medicine as a potent vasodilator (causing dilation of the vascular system) to treat heart conditions, such as angina pectoris and chronic heart failure . Though it

4429-455: The animal itself, by the people handling the meat, and by their implements. Meat can be kept edible for a much longer time – though not indefinitely – if proper hygiene is observed during production and processing, and if appropriate food safety, food preservation and food storage procedures are applied. Spoilage of food is attributed to contamination from microorganisms such as bacteria, molds and yeasts, along with natural decay of

4532-562: The bacteria that cause putrefaction. In extremely dry or cold conditions, the normal process of decomposition is halted – by either lack of moisture or temperature controls on bacterial and enzymatic action – causing the body to be preserved as a mummy . Frozen mummies commonly restart the decomposition process when thawed (see Ötzi the Iceman ), whilst heat-desiccated mummies remain so unless exposed to moisture. The bodies of newborns who never ingested food are an important exception to

4635-430: The body and create a cadaver decomposition island (CDI). Liquefaction of tissues and disintegration become apparent during this time and strong odors persist. The end of active decay is signaled by the migration of maggots away from the body to pupate. Decomposition is largely inhibited during advanced decay due to the loss of readily available cadaveric material. Insect activity is also reduced during this stage. When

4738-463: The body and provide more surface area for the development of fly larvae and the activity of aerobic microorganisms. The purging of gases and fluids results in the strong distinctive odors associated with decay. Active decay is characterized by the period of greatest mass loss. This loss occurs as a result of both the voracious feeding of maggots and the purging of decomposition fluids into the surrounding environment. The purged fluids accumulate around

4841-424: The body by mitochondrial aldehyde dehydrogenase ( ALDH2 ), and nitric oxide is a potent natural vasodilator. In medicine , nitroglycerin is probably most commonly prescribed for angina pectoris , a painful symptom of ischemic heart disease caused by inadequate flow of blood and oxygen to the heart and as a potent antihypertensive agent. Nitroglycerin corrects the imbalance between the flow of oxygen and blood to

4944-417: The body seen by mourners , such as the face and hands. The chemicals used in embalming repel most insects and slow down bacterial putrefaction by either killing existing bacteria in or on the body themselves or by fixing cellular proteins, which means that they cannot act as a nutrient source for subsequent bacterial infections. In sufficiently dry environments, an embalmed body may end up mummified and it

5047-487: The body than others. Nitroglycerin as well as the onset and duration of action of each form is different. The sublingual or tablet spray of nitroglycerin has a two minute onset and twenty five minute duration of action. The oral formulation of nitroglycerin has a thirty five minute onset and a duration of action of 4–8 hours. The transdermal patch has an onset of thirty minutes and a duration of action of ten to twelve hours. Continuous exposure to nitrates has been shown to cause

5150-635: The body to stop responding normally to this medicine. Experts recommend that the patches be removed at night, allowing the body a few hours to restore its responsiveness to nitrates. Shorter-acting preparations of nitroglycerin can be used several times a day with less risk of developing tolerance. Nitroglycerin was first used by William Murrell to treat angina attacks in 1878, with the discovery published that same year. Infrequent exposure to high doses of nitroglycerin can cause severe headaches known as "NG head" or "bang head". These headaches can be severe enough to incapacitate some people; however, humans develop

5253-412: The body's tissues. Maggot activity, typically confined to natural orifices, and masses under the skin, causes the skin to slip, and hair to detach from the skin. Maggot feeding, and the accumulation of gases within the body, eventually leads to post-mortem skin ruptures which will then further allow purging of gases and fluids into the surrounding environment. Ruptures in the skin allow oxygen to re-enter

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5356-456: The carcass is located on soil, the area surrounding it will show evidence of vegetation death. The CDI surrounding the carcass will display an increase in soil carbon and nutrients such as phosphorus , potassium , calcium and magnesium ; changes in pH; and a significant increase in soil nitrogen . As the ecosystem recovers from the disturbance, the CDI moves into the dry/remains stage, which

5459-403: The case of his murder was re-opened in the 1990s. Bodies submerged in a peat bog may become naturally embalmed , arresting decomposition and resulting in a preserved specimen known as a bog body . The generally cool and anoxic conditions in these environments limits the rate of microbial activity, thus limiting the potential for decomposition. The time for an embalmed body to be reduced to

5562-404: The charge exceeds about 30 °C (86 °F) (actual value varying by country) or brown fumes are seen in the nitrator's vent, then it is immediately drowned. Nitroglycerin is an oily liquid that explodes when subjected to heat, shock, or flame. The main use of nitroglycerin, by tonnage , is in explosives such as dynamite and in propellants as an ingredient. However, its sensitivity has limited

5665-451: The chemical is almost always encountered as a thick and viscous fluid, changing to a crystalline solid when frozen. Although the pure compound itself is colorless, in practice the presence of nitric oxide impurities left over during production tends to give it a slight yellowish tint. Due to its high boiling point and consequently low vapor pressure (0.00026 mmHg at 20 °C), pure nitroglycerin has practically no odor at room temperature, with

5768-453: The chief source of the unmistakably putrid odor of decaying animal tissue. Prime decomposers are bacteria or fungi , though larger scavengers also play an important role in decomposition if the body is accessible to insects , mites and other animals. Additionally, soil animals are considered key regulators of decomposition at local scales but their role at larger scales is unresolved. The most important arthropods that are involved in

5871-695: The construction of the South Eastern Railway . About 400,000 cubic yards of chalk was displaced in an exercise that it was estimated saved the company six months time and £7,000 in expense. While drilling and blasting saw limited use in pre-industrial times using gunpowder (such as with the Blue Ridge Tunnel in the United States, built in the 1850s), it was not until more powerful (and safer) explosives , such as dynamite (patented 1867), as well as powered drills were developed, that its potential

5974-400: The correct timing of the individual explosions, will guarantee that the tunnel will have an approximately circular cross-section. During operation, blasting mats may be used to contain the blast, suppress dust and noise, for fly rock prevention and sometimes to direct the blast. As a tunnel or excavation progresses the roof and side walls need to be supported to stop the rock falling into

6077-468: The destructive oxidation of organic materials by the hot nitric acid and the release of poisonous nitrogen dioxide gas at high risk of an explosion. Thus, the glycerin mixture is added slowly to the reaction vessel containing the mixed acid (not acid to glycerin). The nitrator is cooled with cold water or some other coolant mixture and maintained throughout the glycerin addition at about 22 °C (72 °F), hot enough for esterification to occur at

6180-414: The distention of the abdomen and gives a cadaver its overall bloated appearance. The gases produced also cause natural liquids and liquefying tissues to become frothy. As the pressure of the gases within the body increases, fluids are forced to escape from natural orifices, such as the nose, mouth and anus, and enter the surrounding environment. The buildup of pressure combined with the loss of integrity of

6283-399: The effects of black powder to that of a wedge, and dynamite to that of a hammer. The most commonly used explosives in mining today are ANFO based blends due to lower cost than dynamite . Before the advent of tunnel boring machines (TBMs), drilling and blasting was the only economical way of excavating long tunnels through hard rock, where digging is not possible. Even today, the method

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6386-484: The explosive. The first to use this method for underwater blasting was Charles Pasley who employed it in 1839 to break up the wreck of the British warship HMS Royal George which had become a shipping hazard at Spithead . An early major use of blasting to remove rock occurred in 1843 when the British civil engineer William Cubitt used 18,000 lbs of gunpowder to remove a 400-foot-high chalk cliff near Dover as part of

6489-399: The first carrion insects to arrive and they seek a suitable oviposition site. The bloat stage provides the first clear visual sign that microbial proliferation is underway. In this stage, anaerobic metabolism takes place, leading to the accumulation of gases, such as hydrogen sulfide , carbon dioxide , methane and nitrogen . The accumulation of gases within the bodily cavity causes

6592-572: The following therapeutic effects during episodes of angina pectoris: subsiding of chest pain, decrease of blood pressure , increase of heart rate, and orthostatic hypotension . Patients experiencing angina when doing certain physical activities can often prevent symptoms by taking nitroglycerin 5 to 10 minutes before the activity. Overdoses may generate methemoglobinemia . Nitroglycerin is available in tablets, ointment, solution for intravenous use, transdermal patches , or sprays administered sublingually . Some forms of nitroglycerin last much longer in

6695-411: The food. These decomposition bacteria reproduce at rapid rates under conditions of moisture and preferred temperatures. When the proper conditions are lacking the bacteria may form spores which lurk until suitable conditions arise to continue reproduction. Decomposition rates and speed may differ or vary due to abiotic factors such as moisture level, temperature, and soil type. They also vary depending on

6798-425: The forest floor. Lignin is one such remaining product of decomposing plants with a very complex chemical structure, causing the rate of microbial breakdown to slow. Warmth increases the speed of plant decay by roughly the same amount, regardless of the composition of the plant. In most grassland ecosystems, natural damage from fire , detritivores that feed on decaying matter, termites , grazing mammals, and

6901-459: The form of sticks, individually wrapped in greased waterproof paper. Dynamite and similar explosives were widely adopted for civil engineering tasks, such as in drilling highway and railroad tunnels , for mining , for clearing farmland of stumps, in quarrying , and in demolition work . Likewise, military engineers have used dynamite for construction and demolition work. Nitroglycerin has been used in conjunction with hydraulic fracturing ,

7004-452: The heart and the heart's energy demand. There are many formulations on the market at different doses. At low doses, nitroglycerin dilates veins more than arteries, thereby reducing preload (volume of blood in the heart after filling); this is thought to be its primary mechanism of action. By decreasing preload, the heart has less blood to pump, which decreases oxygen requirement since the heart does not have to work as hard. Additionally, having

7107-424: The hole during this process was then removed and replaced with a train of gunpowder. This train was ignited by a slow match , often consisting simply of brown paper smeared with grease, intended to burn long enough to allow the person who fires it enough time to reach a place of safety. The uncertainty of this method led to many accidents and various measures were introduced to improve safety for those involved. One

7210-436: The initial amount of breakdown caused by the prior consumers in the food chain . This means the form that organic matter is in, original plant or animal, partially eaten, or as faecal matter when the detritivore encounters it. The more broken down the matter, the faster the final decomposition. The rate of decomposition is governed by three sets of factors: the physical environment (temperature, moisture and soil properties),

7313-402: The journal The Lancet in 1879. A few months before his death in 1896, Alfred Nobel was prescribed nitroglycerin for this heart condition, writing to a friend: "Isn't it the irony of fate that I have been prescribed nitro-glycerin, to be taken internally! They call it Trinitrin, so as not to scare the chemist and the public." The medical establishment also used the name "glyceryl trinitrate" for

7416-456: The legal limit ( permissible exposure limit ) for nitroglycerin exposure in the workplace as 0.2 ppm (2 mg/m) skin exposure over an 8-hour workday. The National Institute for Occupational Safety and Health has set a recommended exposure limit of 0.1 mg/m skin exposure over an 8-hour workday. At levels of 75 mg/m, nitroglycerin is immediately dangerous to life and health . Decomposition Decomposition or rot

7519-489: The material available to decomposers is another major factor that influences the rate of decomposition. Substances like sugars and amino acids decompose readily and are considered labile. Cellulose and hemicellulose , which are broken down more slowly, are "moderately labile". Compounds which are more resistant to decay, like lignin or cutin , are considered recalcitrant. Litter with a higher proportion of labile compounds decomposes much more rapidly than does litter with

7622-457: The melting point and thereby avoid the necessity of thawing frozen explosive. Chemically "desensitizing" nitroglycerin is possible to a point where it can be considered about as "safe" as modern high explosives , such as by the addition of ethanol , acetone , or dinitrotoluene . The nitroglycerin may have to be extracted from the desensitizer chemical to restore its effectiveness before use, for example by adding water to draw off ethanol used as

7725-419: The microbes die, further reducing the quality of older soil organic matter . Drilling and blasting Drilling and blasting is the controlled use of explosives and other methods, such as gas pressure blasting pyrotechnics, to break rock for excavation . It is practiced most often in mining , quarrying and civil engineering such as dam , tunnel or road construction. The result of rock blasting

7828-426: The normal process of decomposition. They lack the internal microbial flora that produces much of decomposition and quite commonly mummify if kept in even moderately dry conditions. Aerobic decomposition takes place in the presence of oxygen. This is most common to occur in nature. Living organisms that use oxygen to survive feed on the body. Anaerobic decomposition takes place in the absence of oxygen. This could be

7931-615: The organic materials. Organisms that do this are known as decomposers or detritivores . Although no two organisms decompose in the same way, they all undergo the same sequential stages of decomposition. The science which studies decomposition is generally referred to as taphonomy from the Greek word taphos , meaning tomb. Decomposition can also be a gradual process for organisms that have extended periods of dormancy. One can differentiate abiotic decomposition from biotic decomposition ( biodegradation ). The former means "the degradation of

8034-564: The oxides of nitrogen have been removed, as opposed to red fuming nitric acid , which contains nitrogen oxides —and concentrated sulfuric acid . More often, this mixture is attained by the cheaper method of mixing fuming sulfuric acid , also known as oleum — sulfuric acid containing excess sulfur trioxide —and azeotropic nitric acid (consisting of about 70% nitric acid , with the rest being water). The sulfuric acid produces protonated nitric acid species, which are attacked by glycerol 's nucleophilic oxygen atoms. The nitro group

8137-456: The physical movement of animals through the grass are the primary agents of breakdown and nutrient cycling , while bacteria and fungi play the main roles in further decomposition. The chemical aspects of plant decomposition always involve the release of carbon dioxide . In fact, decomposition contributes over 90 percent of carbon dioxide released each year. The decomposition of food, either plant or animal, called spoilage in this context,

8240-500: The position of the body, these parts would vary. For instance, if the person was flat on their back when they died, the blood would collect in the parts that are touching the ground. If the person was hanging, it would collect in their fingertips, toes and earlobes. Once the heart stops, the blood can no longer supply oxygen or remove carbon dioxide from the tissues. The resulting decrease in pH and other chemical changes cause cells to lose their structural integrity , bringing about

8343-402: The price per metre of tunnel is lower. This means that shorter tunnels tend to be less economical to construct with a TBM and are therefore usually constructed by drill and blast. Managing ground conditions can also have a significant effect on the choice with different methods suited to different hazards in the ground. The use of explosives in mining goes back to the year 1627, when gunpowder

8446-461: The process include carrion beetles , mites, the flesh-flies (Sarcophagidae) and blow-flies ( Calliphoridae ), such as the green bottle flies seen in the summer. In North America, the most important non-insect animals that are typically involved in the process include mammal and bird scavengers, such as coyotes , dogs , wolves , foxes , rats , crows and vultures . Some of these scavengers also remove and scatter bones, which they ingest at

8549-431: The proliferation of anaerobic organisms . These multiply, consuming the body's carbohydrates , lipids and proteins , to produce a variety of substances including propionic acid , lactic acid , methane , hydrogen sulfide and ammonia . The process of microbial proliferation within a body is referred to as putrefaction and leads to the second stage of decomposition known as bloat. Blowflies and flesh flies are

8652-481: The quantity and quality of the dead material available to decomposers, and the nature of the microbial community itself. Decomposition rates are low under very wet or very dry conditions. Decomposition rates are highest in damp, moist conditions with adequate levels of oxygen. Wet soils tend to become deficient in oxygen (this is especially true in wetlands ), which slows microbial growth. In dry soils, decomposition slows as well, but bacteria continue to grow (albeit at

8755-516: The release of cellular enzymes capable of initiating the breakdown of surrounding cells and tissues. This process is known as autolysis . Visible changes caused by decomposition are limited during the fresh stage, although autolysis may cause blisters to appear at the surface of the skin. The small amount of oxygen remaining in the body is quickly depleted by cellular metabolism and aerobic microbes naturally present in respiratory and gastrointestinal tracts, creating an ideal environment for

8858-485: The same as when they died. In some religious groups, this is known as incorruptibility . It is not known whether or for how long a body can stay free of decay without artificial preservation. Various sciences study the decomposition of bodies under the general rubric of forensic science because the usual motive for such studies is to determine the time and cause of death for legal purposes: The University of Tennessee Anthropological Research Facility (better known as

8961-530: The same reason. Large quantities of nitroglycerin were manufactured during World War I and World War II for use as military propellants and in military engineering work. During World War I, HM Factory, Gretna , the largest propellant factory in the United Kingdom , produced about 800 tonnes of cordite RDB per week. This amount required at least 336 tonnes of nitroglycerin per week (assuming no losses in production). The Royal Navy had its own factory at

9064-425: The season of death all determine how fast a fresh body will skeletonize or mummify . A basic guide for the effect of environment on decomposition is given as Casper 's Law (or Ratio): if all other factors are equal, then, when there is free access of air a body decomposes twice as fast as if immersed in water and eight times faster than if buried in the earth. Ultimately, the rate of bacterial decomposition acting on

9167-429: The ship considered inaccessible to scavengers. Freshly skeletonized bone is often called green bone and has a characteristic greasy feel. Under certain conditions (underwater, but also cool, damp soil), bodies may undergo saponification and develop a waxy substance called adipocere , caused by the action of soil chemicals on the body's proteins and fats . The formation of adipocere slows decomposition by inhibiting

9270-435: The skin may also cause the body to rupture. Intestinal anaerobic bacteria transform haemoglobin into sulfhemoglobin and other colored pigments. The associated gases which accumulate within the body at this time aid in the transport of sulfhemoglobin throughout the body via the circulatory and lymphatic systems , giving the body an overall marbled appearance. If insects have access, maggots hatch and begin to feed on

9373-464: The temperature of the ambient environment, during a stage called algor mortis . Shortly after death, within three to six hours, the muscular tissues become rigid and incapable of relaxing, during a stage called rigor mortis . Since blood is no longer being pumped through the body, gravity causes it to drain to the dependent portions of the body, creating an overall bluish-purple discoloration termed livor mortis or, more commonly, lividity. Depending on

9476-408: The tissue will depend upon the temperature of the surroundings. Colder temperatures decrease the rate of decomposition while warmer temperatures increase it. A dry body will not decompose efficiently. Moisture helps the growth of microorganisms that decompose the organic matter, but too much moisture could lead to anaerobic conditions slowing down the decomposition process. The most important variable

9579-472: The two horses. The UK Government was so alarmed at the damage caused and what could have happened in a city location (these two tons were part of a larger load coming from Germany via Liverpool) that they soon passed the Nitro-Glycerine Act of 1869. Liquid nitroglycerin was widely banned elsewhere, as well, and these legal restrictions led to Alfred Nobel and his company's developing dynamite in 1867. This

9682-424: The usefulness of nitroglycerin as a military explosive; less sensitive explosives such as TNT , RDX , and HMX have largely replaced it in munitions. Alfred Nobel developed the use of nitroglycerin as a blasting explosive by mixing nitroglycerin with inert absorbents , particularly " Kieselgur ", or diatomaceous earth . He named this explosive dynamite and patented it in 1867. It was supplied ready for use in

9785-451: The viscosity of the mix, are commonly known as "gelatins". Following the discovery that amyl nitrite helped alleviate chest pain, the physician William Murrell experimented with the use of nitroglycerin to alleviate angina pectoris and to reduce the blood pressure . He began treating his patients with small diluted doses of nitroglycerin in 1878, and this treatment was soon adopted into widespread use after Murrell published his results in

9888-486: The workplace, leading to the development of tolerance for the venodilating effects. Over the weekend, the workers lose the tolerance, and when they are re-exposed on Monday, the drastic vasodilation produces a fast heart rate , dizziness, and a headache. This is referred to as "Monday disease." People can be exposed to nitroglycerin in the workplace by breathing it in, skin absorption, swallowing it, or eye contact. The Occupational Safety and Health Administration has set

9991-572: Was first used in place of mechanical tools in the Hungarian (now Slovak ) town of Banská Štiavnica . The innovation spread quickly throughout Europe and the Americas. The standard method for blasting rocks was to drill a hole to a considerable depth and deposit a charge of gunpowder at the further end of the hole and then fill the remainder of the hole with clay or some other soft mineral substance, well rammed, to make it as tight as possible. A wire laid in

10094-748: Was fully realised. Drilling and blasting was successfully used to construct tunnels throughout the world, notably the Fréjus Rail Tunnel , the Gotthard Rail Tunnel , the Simplon Tunnel , the Jungfraubahn and even the longest road tunnel in the world, Lærdalstunnelen , are constructed using this method. In 1990, 2.1 billion kg of commercial explosives were consumed in the United States (12 m per capita), representing an estimated expenditure of 3.5 to 4 billion 1993 dollars on blasting. In this year

10197-413: Was invented by Nobel in 1875, using nitroglycerin, wood pulp , and sodium or potassium nitrate . This was an early, low-cost, flexible explosive. Nitroglycerin belongs to a group of drugs called nitrates, which includes many other nitrates like isosorbide dinitrate (Isordil) and isosorbide mononitrate (Imdur, Ismo, Monoket). These agents all exert their effect by being converted to nitric oxide in

10300-509: Was made by mixing nitroglycerin with diatomaceous earth (" Kieselguhr " in German) found in the Krümmel hills. Similar mixtures, such as "dualine" (1867), "lithofracteur" (1869), and " gelignite " (1875), were formed by mixing nitroglycerin with other inert absorbents, and many combinations were tried by other companies in attempts to get around Nobel's tightly held patents for dynamite. Dynamite mixtures containing nitrocellulose , which increases

10403-432: Was previously known that these beneficial effects are due to nitroglycerin being converted to nitric oxide , a potent venodilator, the enzyme for this conversion was only discovered to be mitochondrial aldehyde dehydrogenase ( ALDH2 ) in 2002. Nitroglycerin is available in sublingual tablets , sprays, ointments, and patches. Nitroglycerin was the first practical explosive produced that was stronger than black powder . It

10506-431: Was replacing the iron wire, by which the passage for the gunpowder is formed, with one of copper, to eliminate sparking that could ignite the powder prematurely. Another was the use of a safety fuse . This consisted of small train of gunpowder inserted in a water-proof cord, which burns at a steady and uniform rate. This in turn was later replaced by a long piece of wire that was used to deliver an electric charge to ignite

10609-603: Was synthesized by the Italian chemist Ascanio Sobrero in 1846, working under Théophile-Jules Pelouze at the University of Turin . Sobrero initially called his discovery pyroglycerine and warned vigorously against its use as an explosive. Nitroglycerin was adopted as a commercially useful explosive by Alfred Nobel , who experimented with safer ways to handle the dangerous compound after his younger brother, Emil Oskar Nobel , and several factory workers were killed in an explosion at

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