Development and use of explosives over the past century

The history of explosives and propellants, also known generally as ‘energetic materials’ began with the material known as gunpowder or black powder, whether the intended use was for civil applications such as rock blasting, military uses in demolition, shell filling (bursting charges) and construction projects, or military and civilian propellant charges for short guns, pistols, rifles or artillery. The individual inventor of black powder will undoubtedly forever remain unknown, but numerous writers such as Drinker (1878), Munroe (1888), Marshall (1915), and Davis (1941, 1943), described what is known about its development and evolution.Until the discovery of nitrated explosive compounds such as nitrocellulose by schonbein and Bottger (independently of one another) and nitroglycerin by Sobrero (all occurring in 1846), the only explosive available for any purpose was black powder. 1) Solid (particulate) propellants; 2) Military explosives; 3) Commercial explosives. Propel lants Propellants may be granular, solid, or liquid. The primary focus was on granular (particulate) material since they are the most commonly encountered by the forensic chemist.Solid propellants are deflagrating materials designed to accelerate a projectile from its position of rest at the breech of a weapon to its full velocity as it exits the tube or barrel. In the ideal (and designed for case), the complete consumption of the propellant and the exit of projectile occurs at the same instant. Propellant gains are thus chemically formulated and physically designed to achieve this end. The gains burn particle to particle at speeds below the speed of sound in the material: this defined the word ‘deflagrating’. Historically such materials have been termed progressive powders.In addition to burning particle- to- particle burns from its free surface inward or, in the case of perforated grains, also from the free surface outward. This characteristic enables the propellant d esigner to size and configure the grains or particles to be totally consumed at the optimum instant. Propellant gains may be found in multitude of shapes and sizes, as might be expected given the varieties of weapons and desired pressures and projectile velocities. Black powder Black powder is the mixture of three components, generally (and originally) charcoal, sulfur, and potassium nitrate.These are typically in the ratio of 15:10:75. Many variations to that ratio have been used: Cundill (1889) lists over 20 varieties, many with sub –varieties. Most of the differences, however, are insignificant. The one major development in the past 100 years is the use of sodium nitrate in some black powder grades. Black powder has an inherent drawback as a military propellant due to the fact that it produces a solid reaction product. Because of this, a dense black cloud is produced upon firing weapon is readily apparent, and after a number of rounds are fired the volume of battlefield sm oke leads to confusion and general chaos.For this reason the development of the ‘smokeless’ propellant charge was an objective of every governments weapons laboratory. Upon the discovery of the nitration reaction this research intensified. Smokeless powder The early history of the nitrated carbohydrates, which includes the 1833 discovery of nitro-starch (called xyloidine by its discoverer, Braconnot) and guncotton, called pyroxyline or pyroxyle be the chemist Pelouze, is thoroughly covered by Devis (1941).Guncotton, nitrocellulose of high nitrogen content (13. 35% to 13. 45%), was the first nitrated material to be tried as a replacement for black powder, but it was too prone to accidents. However its military use continued after it was found that the newly –invented mercury fulminate blasting cap would cause compressed guncotton to detonate, leading to its application as a demolition charge and shell filling. Its use was rather short lived, however due to the int roduction of picric acid.Research was continued on nitrocellulose of lower nitrogen content as a propellant material, and the first good smokeless riffle powder was produced by Vielle in 1886, for the French Government. This was nitrocellulose with either alcohol, kneaded in bread making type machine, rolled out into thin sheets, and then cut into small squares and dried (Military Explosives, 1924). This was a ‘single base’ smokeless powder (nitrocellulose only). In 1888 Nobel invented a powder called Ballistite, which was a low nitrated nitrocotton gelatinized with nitroglycerin: which came to be known as; double base’ powder.In the same year Cordite (given that name because it was extruded in the form of cord or ribbon), a mixture of high nitrated guncotton, nitroglycerine, and Vaseline, gelatinized by means if acetone was developed by an English Committee. (Marshall, 1915) Later ‘triple base’ smokeless powder were developed, containing nitro guani dine in addition to the nitrocotton and nitroglycerin of typical double base powders. Triple base powders were cooler-burning than the single or double base materials and use was mainly restricted to large caliber weapons.Developments in smokeless powder since those early days had been primarily to improve stability, decrease the erosion of the barrel of the weapon, control pressures, decrease smoke output (‘smokeless’ powders are smokeless in comparison to black powder, but still produce visible smoke), and to decrease the muzzle flash from a firing weapon. The geometry of powders may include flakes, tubes, cylinders, sticks, flattened balls, or spheres. Military Explosives As black powder was the first propellant, so it was the first military explosive too.It was used for shell filling, demolition, and military construction projects from the earliest times up until the invention of nitroglycerin. Military explosives as discussed here are those used as the shell filing or ‘bursting charge’ in artillery round and those explosives used for demolition charges. Military construction projects typically use commercial-type explosives, except in field-expedient situations. The brief use of guncotton as a military explosive was noted above. Trinitrotoluene (TNT)During and after World War I the explosive trinitrotoluene (TNT, C7H5N3O6) became the dominant shell filling and demolition charge material. TNT has the advantage of being very easy to cast, since it has a wide spread between its melting and decomposition temperatures. One disadvantage is its extreme insensitivity. In the order to conserve TNT for small caliber shells in World War I, a mixture of TNT and ammonium nitrate (‘amatol’) was developed. It was specified for use only in shell of $. 7-inch to 9. 2-inch diameter (Crowell, 1919) but in actual practice it was used in all sizes.For the same reason of conserving TNT, nitro starch explosives were used very successfully in that war for hand grenades and trench mortar shells (Williams, 1920). Tetryl Tetryl (2, 4, 6-trinitrophenyllmethylnitramine, N-2, 4, 6-tetra-nitro-N-methyl aniline, or picrylmethyl nitramine) was used in military boosters, but has generally been replaced by materials such as RDX and HMX. The ‘tetrytols’ are mixtures of tetryl and TNT, which were utilized in boosters, demolition charges, shells, and shaped charges. The TNT generally ranged from 20 to 35 percent of the mixture.An advantage of tetrytol is that it allows the casting of the explosive into munitions rather than requiring pressing. It is also more powerful than TNT, but not as sensitive as tetryl alone. RDX and HMX Between the world Wars a number of explosives were developed, and after the start of the second war a vast amount of explosives research took place. One of the most important and useful military explosive is RDX (an acronym for ‘Research Department Explosive’), which was discovered i n 1899, but not used until World War II.It is also called cyclonite, hexagen, and cyclo-trimethylenetrinitramine. HMX was another explosive used for military applications during and after World War II. The initials are said to stand for â€Å"High Melting Explosive’, although other sources for the acronym are sometimes cited. It is also called cyclo-tetramethylenetetranitramine or octogen. (Beveridge 1-4) Blasting and Use of Explosives Only authorized persons can handle and use explosives. No person using explosives is allowed to be under the influence of alcohol or drugs.Nothing which could be an ignition source, such as matches, open flames, or smokers, is to be around explosives. Accountability is required to assure that explosives are under the care of a qualified person. All blasting aboveground is done between sunup and sundown and, when blasting is done, blasters are to take special precaution near public utilities, around transportation conveyances, and near public a reas to assure safety and mitigate any damage. Care must be taken to assure that accidental premature ignition does not occur from stray electrical sources or radio transmitters.The blaster is to be considered a competent person in the use and care of explosives, and have experience with the type of blasting methods being used. The transportation of explosive and blasting materials must conform to the department of Transportation regulatory provisions. Drivers of trucks containing explosives and blasting equipment must be licensed and should be in good physical and mental condition. No blasting materials are to be transported with other cargo and blasting caps are not to be transported in the same vehicle as other explosives.These vehicles should be marked with a placard signifying â€Å"Explosives† and have a fully charged fire extinguisher. (Reese, Edison 648) Different uses of an Explosive Blasting is extremely important both to mining and the world economy. The saying is often used, â€Å"If it can’t be grown it has to be mined,† however if the ground is too hard to be mechanically mined economically, it has to be blasted. Certainly many materials, such as iron, copper and concrete to name but a few would be significantly more expensive if it weren’t for explosives and our ability to easily drill holes to use these explosives efficiently.Shock wave compression technology is not only a means of extremely high-pressure generation, but also a means of extremely high-temperature production in solids. When dynamite shock load is applied to solids by means of explosive and high-speed impact, the shock pressure and the shock temperature generated depend on the shock load and the density of the solid. Between 1985 and early 1991, there were 182 incendiary or explosive devices planted in Great Britain by animal-rights activists.This number accounted for approximately 50 percent of all explosive devices planted in all of Great Britain, ma king it numerically a larger problem in Great Britain than incidents attributed to the provisional Irish Republican Army. However, the majority of these devices were far less sophisticated and far less dangerous than the PIRA devices. In 1980 in Great Britain, the first use of high explosives by animal-rights terrorists took place. These acts appear to have been perpetrates by a small group, which had obtained a high explosive used both in military operations and in commercial applications, such as quarries.First it was used against the staff restaurant at Bristol University, where a 5-puound bomb was set off about midnight, wrecking about two floors of the building. More recently in 1990, the same explosive was used presumably by the same group in two car bobs. In one case, a passing infant was severely wounded. Conclusion During the past centuries, it has been proved that there is a beginning international acknowledgement of the future need for demolition of plants and buildings. There is also evidence of an increasing interest in demolition techniques and the re-use of building materials.There are literally hundreds of different types of explosives, varying from black powder used in pipe bombs (still a favorite of domestic bombers), to dynamite sticks, and from blocks of TNT to plastic explosives that can be molded into diverse forms, including thin sheets. A dozen or so of the most notable explosives are used by the terrorists. Of particular note are the explosives RDX and PETN which, together with plastic and other fillers, compose many plastic explosives such as Detasheet and SEMTEX.Explosives are mostly harmful (destructive) but on the other hand in many cases they are useful (constructive) too. Doctors, Engineers use explosives in a constructive way while at the same time criminals and terrorists use explosive in the destructive way. There are many uses of explosives such as Mining, Pyrotechnics, Building Demolition and even Construction. Explosives ar e also used in Carve Mount Rushmore, Avalanches and are used in backcountry for Trail Maintenance. Explosive are used in Medicines to break-up kidney-stones. Works cited Beveridge, Alexander. Forensic Investigation of Explosions. New York: CRC Press, 1998. 1,2,3,4 Kasai, Yoshio. Kenkyuio, Kenchiku, Kensetsusho. (Japan), Nihon Daigaku. Demolition and Reuse of Concrete and Masonry: Proceedings of the Second†¦.New York: Taylor & Francis, 1998. 49 Technology against terrorism: the federal effort, US: DIANE Publishing, (1992) Reese, D. Charles. Eidson, V. James. Handbook of OSHA Construction Safety and Health New York: CRC Press, 2006. 648

Importance of Research Essay

Jean Piaget is a trailblazer whose focus was on children’s cognitive development. He lay the foundation by naming four stages sensorimotor, preoperational, concrete operational, and formal operational. Each stage builds upon the other, coinciding with biological development of the brain. Although some of his theories were deemed inaccurate, they paved the way and gave direction for upcoming psychologists who were able to build upon his work by disproving some of his theories simply to develop their own. Just as Jean Piaget, several scientists have theorized on many other parts of psychology, but all with general advantages. They provide us with a better understanding of ourselves, they provide us with a better understanding of others, and they provide us with methods to prevent and/or treat mental illnesses. At times it seems as though we do not know ourselves at all. We question our behaviors and feelings. Psychologically understanding these behaviors helps us to understand that we are probably not alone in our feelings. Also, by having a full understanding of self, psychologically, we can learn how to respond to certain feelings and emotions and how to wean ourselves off of them. In the same way that we can further understand ourselves in the study of this field we can apply reverse psychology to understand others. Being able to do so enhances people’s skills and work skills by enabling you to question possibilities and to address them as needed. This makes for more effective communication skills expanding beyond personal life and into the workforce. Lastly, research/experiments in psychology help to treat and prevent mental illnesses. Scientists have discovered biosocial, cognitive, and psychosocial facts that influence mental illnesses. Case studies allow these illnesses to be identified. By knowing what triggers them, scientists can make the general public aware of those that are most influential and can advise of help if at all needed. Factors are considered, tested, and named. Research further helps us to recognize early symptoms or onsets. In conclusion, effective research/experiments play a large role in today’s society. It helps to influence several work fields such as law enforcement in which psychologists profile criminals to help catch them. In major corporations, psychology is used to screen potential candidates or present employees and even as a part of advertising, appealing to consumer’s wants and needs. Even schools use the influence of psychology to enrich student’s learning experiences via group assignments or to enhance athlete’s performances via pep rallies. You see, Psychology is an inevitable part of everyday life. Effective research and experiments help us to better understand our behaviors, thoughts, and emotions enabling us great communication skills and a better well-being.

Discussion question Essay Example | Topics and Well Written Essays - 500 words - 7

Discussion question - Essay Example While this is true however, education does not necessarily translate into economic growth of a country, it is only a single factor to the various reasons for economic growth. Education has faced a significant expansion in the last decades across the world, with countries registering double-digit growth patterns. In the 1990s, the world, according to Easterly (73), had 99 percent enrollment for primary education. Education investment has brought little or no impact in the world economy and especially for the countries themselves. Growth of human capital in a country does not necessarily mean that their contribution to the growth of a country. If the argument that education brings growth to a country, fresh graduates should be entitled to higher salaries than experienced workers should. However, salary increment is based on the years of experience, making this belief to be untrue. In fact, Easterner (77) is of the opinion that, the contribution of education growth and growth of a worker’s output is negligible, stating that in some African countries, this growth is actually negative. The Gross Domestic Product per worker in is just a small percentage in most Eastern Europe and the Soviet Union countries. With time, the median growth rate of poor countries in the world has kept a declining trend overtime, indicating a poor education contribution to growth, yet education received a massive growth. Due to in direct effects of human capital, countries with higher initial human capital are likely to have a faster growth than those with low initial human capital.in case the level of human capital and physical capital are both high, there will be high returns on physical capital investment until there is a balance between the two(76-77). In all nations worldwide, variations in the country’s growth have little contributions from variations in growth of the human capital, rising more serious concerns regarding initial schooling and

Development of Teaching Strategies Research Paper

Development of Teaching Strategies - Research Paper Example While developing a teaching strategy, some of the points that must be considered include but are not limited to the objectives of teaching and its learning outcomes, the needs of students, the desires of students, the previous experience of the students as learners and the strategies of teaching that they are used to, the expertise of the teacher, the resources available to the teacher, and the possible impact of the adjustments made in the teaching method on the teacher. This paper discusses the development of teaching strategies. Fundamentals of Effective Teaching Significance of subject in the teaching strategy Developing an effective teaching strategy is integrally linked with the subject that needs to be taught. Learning needs differ from one subject to another. On one hand, there are subjects that are entirely theoretical e.g. history, politics, and philosophy whereas on the other hand, there are subjects that are mathematical e.g. math and physics etcetera. There is also a thi rd category of subjects that are both theoretical and mathematical simultaneously depending upon the course selected for that subject e.g. risk management. To be able to impart maximum knowledge to the students, it is imperative that a teacher assesses the individualistic needs of the subject being taught. For instance, developing a teaching strategy for the subject of â€Å"History† might not require a teacher to take the students on a field visit because most of the knowledge is essentially gained merely by reading the books whereas for the subject of â€Å"Geology†, a teacher might never consider the job done unless the students have been taken to a field visit and have been provided with an opportunity to see, touch, and feel the rocks, minerals, and metals that constitute a particular strata of Earth. Equal attention While teaching, it is the moral and ethical responsibility of a teacher to provide all students with equal attention. Disparity in the division of at tention of a teacher among the students is one of the causes of poor academic performance of certain students; the ones that are neglected or not sufficiently attended to. â€Å"In this task, teachers are crucial because of the central role they play in promoting participation and reducing underachievement, particularly with children who might be perceived as having difficulties in learning† (Rouse 1). (McGhie-Richmond, Underwood, and Jordan) carried out a study to investigate the skills required for effective teaching in the elementary teachers in the inclusive classrooms. The researchers’ objective was to find out if the appearance of the constructivist skills follows from or is independent of the mastery of more transmissive behaviors of teaching. The researchers found that the patterns of behaviors of teaching were consistent across the students, though the academically ‘at risk’ students were found to be receiving differentiated instruction and less a ttention of the teacher as compared to other students. Differentiated teaching The term â€Å"differentiated teaching† means planning of ways by the teachers to address differences in such factors as age, culture, profile of multiple intelligences, ethnicity, temperament, personality style, development and possible delays in development, and styles of learning of

No topic Assignment Example | Topics and Well Written Essays - 250 words - 14

No topic - Assignment Example In an attempt to resolve the scarcity concern, reliance on chemically processed substitutes or genetically engineered crop products could emerge in the economy but these could have adverse health implications. Use of chemically processed foods may intoxicate people while genetically engineered foods may alter change cell structure to alter people’s body physiology. Farmers would also lose their jobs and this would mean their lost earnings. Following the loss, poverty rate is likely to increase and its effects such as inability to meet social needs are likely. With inability to meet care costs, quality of life is likely to deteriorate and escalate problems that could arise from scarcity of food or use of chemically processed foods (Ball State University 9, 10). Low life expectancy is another anticipated effect of the concern, as residents of the state would suffer from famine. This could also lead to high mortality rate, especially among poor members of the society who have bee n relying on crop farming for their income (Doblhammer, Berg, and Lumey n.p.). Doblhammer, Gabriele, Berg, Gerard, and Lumey, L. â€Å"Long-term effects of famine on life expectancy: A re-analysis of the great Finish famine of 1866-1868.† IZA. February 2011. Web. April 2, 2015. < http://ftp.iza.org/dp5534.pdf

MBTI Preferences Essay Example | Topics and Well Written Essays - 500 words

MBTI Preferences - Essay Example While it was believed that the results would reflect the friendly and interactive nature, they pointed at a preference towards looking within and share significant events with a few close people rather than many acquaintances. The score on this variable is not very strong, and it could be situational factors that affected this factor. There are examples from the workplace as well as from personal experiences that underline the friendly nature and comfort in interacting with even unknown persons. The comfort in being in a position at work that involves interacting with people and keeping negotiations in good humour is itself an indicator of extraverted nature. Thus, it is difficult to accept the test’s result that claim Introversion over personal understanding and experiences that verify Extraversion. The second variable of Sensing – Intuition defines the primary means of conducting an analysis on information available. Both the test results and the hypothesized score fa ll in the same direction – i.e. – Sensing. Individuals high on Sensing will typically rely more on information that is gathered through senses than on inductive reasoning. They also process information deductively. There is a distinct inclination to base decisions and opinions on the basis of verifiable facts and not on assumptions.

What does the experience of school by Japanese youth suggest about the Essay

What does the experience of school by Japanese youth suggest about the education for sustainable development In what ways does it resonate in Malaysia - Essay Example As defined by the World Bank Group, Education is the first step for poverty reduction and to increase human development. It is a primordial element to acquire knowledge. It is stated at the top of every state policy they will implement. Each government makes an effort to improve their system of education, because this will benefit their country, particularly their economy, in the long run. As Milton Freidman stated, the government interferes with its citizens’ education to promote the welfare of the society. An educated individual is a great addition to boost a country’s economic growth and to sustain its future needs, provided that he will be able to apply what he had learned from school. Sustainable development is a concept which deals with the balance on how present demands are meet without compromising the future needs of the young generations. This protects a country from exhausting all its natural resources to meet its present needs without undermining its economi c growth. It is how conflicts should be resolved between the present necessities and the economic development, in order to withstand the upcoming needs. Education for sustainable development is one of the most pressing topics in the world. as discussed in the preceding paragraphs, education is a tool for achieving sustainable development. It provides individuals training, discipline and knowledge. It gives guidance to the future work force. However, though the goal of education for sustainable development is towards a positive result, the idea still has negative implications along the way. ESD not only focused on the academic side of education but also how values are being taught to sustain development. The values formation curriculum varies from one country to another. It depends on how closely knit the cultural ties of a certain country (McKeown, Hopkins, Rizi, &Chrystalbridge 2002). Since the subject on values formation is not universally the same, the approach on the students va ries from one country to another. These problems lead us to the question whether the predicaments in the present education will be able to sustain the impending needs of the future generations. In this paper, a comparative analysis will be presented with regard the education for sustainable development in Japan and Malaysia, and its negative implications to its people. The discussion made on this paper has transcendental importance and must be able to provide us a concrete picture of what is happening in these two countries, and to examine whether such will be advantageous in the long run. Japan and its Economy Japan is one of the most looked up countries, especially in Asia, due to its rapid economic progress. According to Asianinfo.org (2011a), tt is the third largest economy in the world. The currency used by Japan is Yen. It implements a semi-pegged foreign exchange. Japan’s leading industries are manufacturing, construction, communication and distribution. All these sect ors are backed by the country’s labor force (Japan-guide.com 2011). In state.gov (2011) it is stated that the work force in Japan is approximately 65.9 million in 2010, which is divided in three main sectors: Services which is composed of 68 percent of the work force, industry with 28% and agriculture with 4 percent. The literacy rate in Japan in 2010 is an outstanding 99 percent. The literacy statistics show that Japan has an excellent educational system. Education in Japan According to Kaori Okano and Motonori Tsuchiya (1999), education plays a major role on the countries development. Education must be able to cope up with the speedy economic growth of Japan. With that, state