Wednesday, October 30, 2019

The evolution of semiautomatic rifles Essay Example | Topics and Well Written Essays - 1750 words

The evolution of semiautomatic rifles - Essay Example After 1885, smokeless powder and a cupro-nickel jacketed bullet ushered the SR into a new era. Maxim received a patent in 1891 for a short-stroke gas piston, where the gas is taken off through a barrel port close to the chamber, which drives a short piston that operates the action. John Browning, in 1889, entered the SR field, producing a lever rifle that featured a concave muzzle cap that was hook up below the barrel, connecting with the triggerguard rifle lever. Griffiths and Woodgate were two Englishmen who introduced a SR that had simplicity as its value. In 1898, Mauser introduced a SR that incorporate a locking principle which was modified to form the Deglyarev LMG lock principle and the lock of the gas operated rifles with which Germany ended the war. Major Amerigo Cei-Rigotti introduced a gas system in 1900, which was a modification of the Italian 1891 rifle design, but had the action further forward to protect the shooter. The Cei-Rigotti, in firing tests in 1900, delivered 300 rounds in a minute of full automatic fire, after which the barrel was too hot to use. This was a mechanism that was used by the Russians in 1936 and 1940 and by Germany in 1943, with their mechanism being mounted on to of barrels, instead of below. The main person who was driving the development of the SR was Mannlicher. In 1891, Mannlicher developed two SRs, which operated on the short recoil principle. His second experimentation was a rifle that featured a small hook bored in the barrels bottom and a gas-operated arm. Mannlicher came back in 1893 with two SRs with a revolving bolt locked rifle. The first was a modification of his standard turning bolt magazine rifle; the second was the Mannlicher Model 90 straight-pull design. In 1894, Mannlicher introduced two â€Å"blow forward† designs with hesitation locking cams. The first required cocking after every shot. The second featured a standing

Sunday, October 27, 2019

Sea water desalination

Sea water desalination Abstract Despite the lack of water in some areas of the world in one hand, and the increasing consumption of it in some others make it essential for scientists and engineers to search for practical solutions for this world crisis. This paper closely examined the sea water desalination to be one of the most widespread methods that provide the world with a considerable amount of drinkable water in terms of quality, quantity and cost. Desalination of Seawater is an approach used (and may be the only method) to overcome shortage of fresh water from natural resources in many regions in the world. In recent years, many desalination processes become technically and economically affordable. The production of one cubic meter of desalinated water becomes very reasonably to be less than $1/m3 for many new installations. Introduction Desalination Industry is driven by desalination process such as Multi Stage Flash (MSF) and Reveres Osmosis (RO). Operations of these processes and controlling them are very complicated due to many reasons. Many researchers tried to study dynamic behavior of desalination plants to address plant variables during operation .The plant shutdown can lead to considerable affects or effects on the plant economics. Influence of Plant Factor[1] on Plant Economics . In many researches and new installations, attempts to develop much better and reliable control policy have been investigated and many more are still on going under research . The effective performance and evaluation of different control schemes is important and possibility of implementing new control policies can open new windows for operation of desalination plants for near future. At the same time, this research also aims to improve our understanding of controllability and operability of the desalination plants for better, safer and economic plant operations with maximizing productivity, availability and profitability. The study achievement is believed to be beneficial for desalination community and it helps developing local MENA human resources significantly. Aims and Objectives: Study dynamic behaviors with controllability of MSFs and R.O processes. Emphasis on unique characteristics of desalination processes such as physical, chemical and fluid dynamics will be considered, Simulation of the two methods will be developed on to evaluate the response of a classical desalination system to different operation scenarios based on conventional control schemes. Addressing desalination system components in control policy such as ventilation performance in capturing non-condensable gases, fouling rate formation in condenser tubes, and brine flow hydraulics variations, Computational Fluid Dynamics will be used to describe some complex desalination plant dynamic behavior and phenomena such as brine entrainments to distillate trays and mist eliminator efficiency, and brine level change with orifice configuration, Economic analysis justification for implement iterative Learning control in thermal desalination plants. Why the Work is Important: Recent development of process and control methodology of the desalination plant behavior using its operating data. The integration of performance and process control will allow improve controllability the plants even during failures events. Addressing some dynamic phenomena in the plants and performance of some plants components will be covered with utilisation of Simulation. Economic analysis of implement different the control system will be done. Furthermore, this project will help in developing knowledge capacity and human resources in MENA region. Discussion This study will address two of the most widely used processes of seawater desalination. El-Dessouky and Ettouney argue that, the thermal processes or membrane separation methods are best methods for desalination processes (2002: 11). Based on this point, we are going to analyze an example of each type, namely MSF and RO. Multistage Flashing: MSF is considered to be one of the thermal-based processes to desalinate seawater. Simply put, seawater goes through a process of evaporation followed by that of condensation. Based on this observation, we may conclude that the process at hand imitates the kind of evaporation that occurs in nature. The mechanism in which this takes place is explained by the National Research Council (2004: 76) who points out that: MSF uses a series of chambers, each with successively lower temperature and pressure, to rapidly vaporize (or â€Å"flash†) water from bulk liquid .The vapour is than condensed by tubes of the inflowing feed water, thereby recovering energy from the heat of condensation. As it turns out, heat is the main source of energy needed for this process to take place. Multistage flash. SOURCE: Buros et al. (1980); Buros (2000). Reverse Osmosis : RO is viewed as one of the membrane-based processes to desalinate seawater. In this method high pressure during semi-permeable membranes permeates the fresh water of highly concentrated brine solution (El-Dessouky and Ettouney 2002, P. 12). Thus, the efficiency of this technique is mainly dependent on how good the membranes are in separating salts, metals and other materials from water. Unlike other membrane processes, RO relies on the pressure put on seawater against the membrane, the higher the pressure the better. The following flow chart explains this process: (RBF Consulting, 2004) Seawater Reverse Osmosis Plant SOURCE: RBF Consulting 2004. Three criteria will be considered to investigate the advantages and disadvantages that each method has: The Quantity and Quality of the Produced Water: According to RBF Consulting (2004), the fresh water produced by MSF constitutes around 61.6 % of the desalted water in the world. This is, of course, not strange since this method has been used since the mid 1940s. Specifically, the desalted water produced in winter is more than that in summer. Obviously, this does not comply with what is required. To solve this problem, we might ensure that the plant is provided with high temperatures all the year around. However, this might lead to the gradual corrosion of the plant equipment. On the other hand, the amount produced by RO comprises around 26.7 % of the overall production as indicated by RBF Consulting (2004). Interestingly, Saudi Arabia is ranked second in the world with approximately 12.9 % of the desalted water produced by RO. However, the amount produced by MSF is almost twice as much as the amount produced by RO. The following table shows the change in the capacity of the desalted water in Saudi Arabia: Water Desalination in the UK. This is considered to be new in one of the wettest countries in the world. This tendency towards this source of drinkable water can be ascribed to two factors: Firstly, there has been an increasing prediction or fear of drier summers. Secondly, the constant growth of population makes it necessary to quickly find alternatives to water sources. This is actually a point of difference between Saudi Arabia and the UK. Specifically, Saudi Arabias production of desalted water will necessarily be much bigger than that of the UK, because Saudi Arabia is thought to be one of the driest places in the world. As for the method adopted in the UK, it has been argued that RO is preferred to MSF as being less expensive. This follows from the reduction in the capital costs of membranes, which eventually leads to the reduction in the operational costs. Indeed, RO is chosen to desalinate water in the Beckton Plant in East London which is meant to take saline water from River Thames. This plant is expected to reach a capacity of 150 MLD that will be sufficient for 400.000 households as indicated by Bennett (2005). As far as quality is concerned, it is evident that water produced by MSF is very pure. However, the purity of the water produced by RO depends on the efficiency of the membrane. In other words, it relies on the ability of the membrane to capture minerals, salt particles and materials. Thus, we may say that purity is one of the advantages that MSF has over RO. The Cost of the Produced Water: The inclination of some countries to adopt RO in seawater desalination although it provides less pure water can be linked with the lower costs required for this process. Dickie (2007: 11) argues that large scale thermal desalination has been completely limited to the rich, energy affluent and water poor countries nearby the Arabian Gulf. Based on this observation, we may account for the wide use of MSF in Saudi Arabia since this country is rich with energy sources required for this process as discussed before. This also justifies the use of RO in the UK as being less expensive. In fact, RO tends to be the optimal method to desalinate seawater all over the world. The Team Work: This project is based on a MSc program in the University of Newcastle and it will establish a promising cooperation between two RD organizations; Saline Water Conversion Corporation (SWCC) and School of Chemical Engineering and Advanced Materials in the University of Newcastle. The principle investigator, Nasser Zouli, is a member of taskforce team of project on performance of desalination plants in the (SWCC). The project has evaluated more than 20 desalination plants.

Friday, October 25, 2019

Luis Valdezs Los Vendidos Essay example -- History Historical Los Ven

Luis Valdez's Los Vendidos "Los Vendidos," which translates from the literal Spanish to "The Sold Ones" or a more appropriate translation of the title is "The Sell Outs." This is a satiric play written by Luis Valdez and performed by "El Teatro Campesino," which translates into "The Farmworkers’ Theater." El Teatro Campesino, founded by Luis Valdez in 1965, was a group of California farmworkers who put together "Actos," or "Skits." These "Actos" were made mainly to entertain "striking farmworkers, support them in their marches, and attract public attention to their strikes and organization" (http://www.pbs.org/chicano/bios/lvaldez.html). Though there is much comedy in the play, it brings about many important social issues that faced Mexicans and Mexican-Americans in the U.S. during the 1960’s. Even after almost three decades, these social issues are still apparent in Mexican-American society and others as well. While I was aware of such movements, such as the Black Panthers’ moveme nt observed in African-American history, I was never aware of the hardships facing Latin@s, such as Chicanos, in the U.S. By analyzing "Los Vendidos" through class readings, class notes, notes from a speaker, and Internet resources, I can easily further my understanding of a society that was in need of equality. In the first part of the video, our "Latin@s in the U.S.A." class was shown part of Chicano! The part of the video documentary that our class saw showed us a brief summary of what life was like for Mexicans in the 1960’s. The way Mexicans were treated by the U.S. government wasn’t fair. For instance this is seen, in Chicano!, when "journalist Ruben Salazar, who is the news director of KMEX and a columnist for the L.A. Times,... ...em did not want to go. After watching "Los Vendidos," and after laughing a little or a lot, all the underlying messages, or most of them, are jumping straight out of the film. The more the film is watched, the more the underlying messages you’ll find dwelling in this bed of knowledge and hidden beneath the sheets of comedy and sarcasm. At the end, we find out that Honest Sancho was the real robot and that all the people he was trying to sell were just acting. Each member in the lot feels for Eric, whose real name is Kiki, because he really did not want to leave with the secretary, Miss Jimenez. Though it seemed throughout the play that Chicanos did not know what to do, the last segment of the play clarifies all. By taking out a map, the Chicanos continue to work systematically figuring out how to disperse as many Chicanos to as many communities as possible.

Thursday, October 24, 2019

Charismatic style of Leadership

I have chosen the leader of a local foundation in our community who had been in the public eye due to his tireless efforts and initiative in addressing the homeless problem that are common even in suburban America. The person exhibits all three characteristics which include firstly, charm and grace, a primary characteristic of charismatic type of leadership. Secondly, the leader has the ability to command respect because he has immense self-belief that he can accomplish a lot for the homeless people. Thirdly, this person or leader has been influential as well because he can draw people in the upper echelon of society to support in many aspects of their program. People, both within the volunteer and paid staff, the homeless themselves and the supporters respect, abide by and pursue this leader’s vision and plans because they see firsthand his transparency and personally admire or have a high regard for his manner of dealing with the staff. This is what is called intense â€Å"attraction† to a leader because of his/her ability to command respect, conduct with such verve and energy (â€Å"Charismatic Leadership, 2007). When they hold meetings or when this leader speaks to people, he sees everyone in the room, and seems to convey at a level of â€Å"closeness.† The leader picks at the moods and behavior of the moment and then tailors what he is going to do next based on those observations. The leader employs different methods or strategies to get the attention of the followers, is very persuasive and very effective in using gestures and body language (â€Å"Charismatic Leadership, 2007). When this person leads his team, he tries to create a distinction about his group in contrast with that of others. He builds the uniqueness of the group in the eyes of members and makes efforts to solidify the group’s adherence to the leader but the members expect as well of their leader’s loyalty towards them. He exhibits leadership skills coupled with a positive outlook and is other –oriented which results to changes for the good of the team usually (â€Å"Charismatic Leadership, 2007). Reference: _________ â€Å"Charismatic Leadership†. 2007. Changing minds.org. Accessed March 24, 2008

Wednesday, October 23, 2019

The Enlightenment

The Enlightenment BY unet193 World Literature The Enlightenment's Impact on the Modern World The Enlightenment, Age of Reason, began in the late 17th and 18th century. This was a period in Europe and America when mankind was emerging from centuries of ignorance into a new age enlightened by reason, science, and respect for humanity. This period promoted scientific thought, skeptics, and intellectual interchange: dismissing superstition, intolerance, and for some, religion. Western Europe, Germany, France, and Great Britain, and the American Colonies generally influenced the age of reason.Following the Renaissance, science and rationality was the forefront of this age. The enlightenment came as a wave throughout Europe, drastically changing the culture. The literature of time reflected this idea. Authors such as Voltaire and Jean-Jacques Rousseau were torchbearers of this time, writing Enlightenment literature and philosophy. The Enlightenment was the forefront for modern literature a nd changed the way people viewed and interacted with the world, without it society today would not be the same. The ideas of the Enlightenment have had a long-term major impact on the culture, politics, and governments of theWestern worlds. English philosopher John Locke's principles of religious tolerance, the separation of church and state, and the social contract, for instance, greatly influenced the Founding Fathers of the United States as they planned their new country. Locke's idea of a social contract, which Rousseau in particular developed, was also of great importance in France both before and after the French Revolution. Democratic institutions were in existence to some degree in England, Switzerland, and the United Province of the Netherlands when Rousseau elaborated his social contract.Many of the ideas that the philosophers developed are intrinsic to modern democratic society, and they were often developed with the intent of creating such a society. It is important to n ote that Enlightenment thinkers were not the only source of such ideas. These are only two of many examples of how these ideas influenced later events. In fact, these three countries were important centers for printing and discussion, even though much of the discussion was about how to change the repressive society in France; French exiles, including both Rousseau and Voltaire, took efuge in these countries when the French state sought to silence them.The 18th century was a time, which saw a significant expansion of knowledge in the realm of the natural world. In conjunction with the emerging philosophical enquiry of the Enlightenment, men of science began to investigate widespread beliefs about the structure of the universe, and even the type of knowledge that was possible for the human mind to understand. A great many of the Enlightenment writers possessed a background in the sciences, or a willingness to conduct scientific experiments. Adam Smith, US representative and philosophe r states, Science is the great antidote to the poison of enthusiasm and superstition. (Smith) Like many he believed that in order to clear the mind ot talse superstition and tocus on the true nature of a human science was necessary. A notable opponent was Rousseau, he believed that science led to the distancing of mankind from nature and often worked against the improvement and development of individuals. The spread of science in the 18th century was enhanced by the numbers of scientific societies and academies which had started to emerge in the previous century and which, in eneral, accepted â€Å"Newtonianism† over the Cartesian system.It should be noted, however, that science was not a term often used by Enlightenment thinkers; the use of natural philosophy illustrates that it was originally conceived of as a line of enquiry that shared contact points with moral philosophy and epistemology. The philosophers generally favored reducing government control over the market, whi ch we call â€Å"laissez-faire† economics. The most prominent school of laissez-faire thinkers in France were the physiocrats, who believed that the only real ource of national wealth was agriculture.An unobstructed supply of grain in France would be a means of increasing total output. In 1776 Adam Smith published The Wealth of Nations, which forwards similar ideas. Smith was somewhat different from the physiocrats, though, because he believed that labor and the market were the prime creators of wealth. Smith argues â€Å"The greatest improvement in the productive powers of labour, and the greater part of the skill, dexterity, and Judgment with which it is anywhere directed, or applied, seem to have been the effects of the division of abour. (Smith) He believes labor for one owns success is the best way to work, not wealth based on social standings. In making these arguments, both the physiocrats and Adam Smith struck at the hold that the aristocracy was trying to maintain o n the economy. Locke agrees, â€Å"All wealth is the product of labor† The laissez-faire economists believed that wealth should not be confined to one class. As articulated in France, therefore, the argument for laissez-faire economics was an argument that the ancient regime should be abolished and replaced with a more equal basis for ociety.Most literature was nonfiction, which means it was based on fact rather than being made up by the author's imagination. Its aims were to instruct, to enlighten, and to make people think. Immanuel Kant, German philosopher, states â€Å"Two things inspire me to awe: the starry heavens above and the moral universe within. â€Å"(Kant) He explains the sort of wonder and inspiration found in the literature of the Enlightenment age Two of the primary targets of critical examination during the Enlightenment were governments and religious authorities.These calls for reform ere raised by some of the most eloquent writers in history, such that th e Enlightenment is also known as the golden age of satire. The two leading figures of Enlightenment satire are Voltaire (in French) and Swift (in English). Voltaire battled many forms of injustice, including religious and political discrimination, arbitrary imprisonment, and torture. He is known primarily for his many philosophical and satirical works, including novels, short stories, and essays. His masterpiece is the novel Gulliver's Travels, a broad examination of ethics, politics, and society framed in series of fantastic adventures.During the late seventeenth century, France waxed as the supreme political and cultural power of Europe. Classical French literature flourished especially in the form of drama. French tragedy peaked in the works of Jean Racine, while Moliere, otten considered the greatest ot all French dramatists, attained the pinnacle of French comedy. While ancient and medieval writers produced novels, the form received unprecedented attention in modern times. Form ative age novel writing flourished primarily in Spanish, French, English, and German.As the novel did not achieve its supreme position until the nineteenth century, novelists of the formative age are generally less prominent than other literary fgures, namely poets and dramatists. Nonetheless, a list of the foremost novelists of the formative age will be attempted here: in Spanish, Cervantes; Defoe's foremost work, Robinson Crusoe, is likely the most widely familiar novel of the entire formative age. These ideas, works, and principles of the Enlightenment would continue to affect Europe and the rest of the Western world for decades and even centuries to come.Nearly every theory or fact that is held in modern science has a foundation in the Enlightenment; Yet it is not simply the knowledge attained during the Enlightenment that makes the era so pivotal†it's also the era's groundbreaking and tenacious new approaches to investigation, reasoning, and problem solving that make it s o important. although some may have been persecuted for their new ideas, it nevertheless became indisputable that thought had the power to incite real change. Just like calculus or free trade, the very concept of freedom of expression had to come from somewhere, and it too had firm roots in the Enlightenment.