Background information about waste disposal practices Essays

Background information about waste disposal practices Essays Background information about waste disposal practices Paper Background information about waste disposal practices Paper A primary objective of waste management today is to protect the public and the environment from potentially harmful effects of waste. Some waste materials are normally safe, but can become hazardous if not managed properly. For example, 1 gal (3. 75 1) of used motor oil can potentially contaminate one million gal (3,790,000 1) of drinking water . Every individual, business, or organization must make decisions and take some responsibility regarding the management of his or her waste. On a larger scale, government agencies at the local, state, and federal levels enact and enforce regulations governing waste management. These agencies also educate the public about proper waste management. In addition, local government agencies may provide disposal or recycling services, or they may hire or authorize private companies to perform those functions. Throughout history, there have been four basic methods of managing waste: dumping it, burning it, finding another use for it (reuse and recycling), and not creating the waste in the first place (waste prevention). How those four methods are utilized depends on the wastes being managed. Municipal solid waste is different from industrial, agricultural, or mining waste. Hazardous waste is a category that should be anteed separately, although it sometimes is generated with the other types. The first humans did not worry much about waste management. They simply left their garbage where it dropped. However, as permanent communities developed, people began to dispose of their waste in designated dumping areas. The use of such open dumps for garbage is still common in many parts of the world. Open dumps have major disadvantages, however, especially in heavily populated areas. Toxic chemicals can filter down through a dump and contaminate groundwater . The liquid that filters through a dump or landfill is called leached. Dumps may also generate methane, a flammable and explosive gas produced when organic wastes decompose under anaerobic (oxygen-poor) conditions. The landfill, also known as the sanitary landfill, was invented in England in the 1 sass. Ata landfill, the garbage is compacted and covered at the end of every day with several inches of soil . Landfill became common in the united States in the sass. By the late sass, it was the dominant method for disposing municipal solid waste in the nation. Early landfills had significant problems with leached and methane, but those have largely been resolved at facilities built since about he early 1 sass. Well-engineered landfills are lined with several feet of clay and with thick plastic sheets. Leached is collected at the bottom, drained through pipes, and processed. Methane gas is also safely piped out of many landfills. The dumping of waste does not just take place on land. Ocean dumping, in which barges carry garbage out to sea, was once used as a disposal method by some United States coastal cities and is still practiced by some nations. Sewage sludge, or waste material from sewage treatment, was dumped at sea in huge quantities by New York City as recently as 1 992, but his is now prohibited in the United States. Also called bossily, sewage sludge is not generally considered solid waste, but it is sometimes composted with organic municipal solid waste. Burning has a long history in municipal solid waste management. Some American cities began to burn their garbage in the late nineteenth century in devices called crematory. These Were not very efficient, however, and cities went back to dumping and other methods. In the 1 sass and sass, many cities built new types of more-efficient garbage burners known as incinerators. The early incinerators were rather dirty in arms of their emissions of air pollutants, and beginning in the sass they were gradually shut down. However, in the 1 9705, waste burning enjoyed another revival. These newer incinerators, many of which are still in operation, are called resource recovery or waste-to-energy plants. In addition to burning garbage, they produce heat or electricity that can be used in nearby buildings or residences, or sold to a utility. Many local governments became interested in waste-to-energy plants following the energy crisis in 1973. However, since the mid-1 sass, it became difficult to find locations to lid these facilities, mainly because of public opposition focused on air- quality issues. Another problem with incineration is that it generates ash, which must be landfill. Incinerators usually reduce the volume of garbage by 70-90%. The remainder of the incinerated waste comes out as ash that often contains high concentrations of toxic substances. Municipal solid waste will likely always be landfill or burned to some extent. In the past 25 years, however, non-disposal methods such as waste prevention and recycling have become more common. Because of public concerns and the high costs of entangling and burning (especially to build new facilities), local governments want to reduce the amount of waste that must be disposed in these ways. Municipal solid waste is a relatively small part of the overall waste generated in the United States. More than 95% of the total 4. 5 billion tons of solid waste generated in the United States each year is agricultural, mining, or industrial waste. These wastes do not receive nearly as much attention as municipal solid waste, because most people do not have direct experience with them. Also, agricultural and mining wastes, which make up 88% of the overall total f solid waste, are largely handled at the places they are generated, that is, in the fields or at remote mining sites. Mining nearly always generates substantial waste, whether the material being mined is coal , clay, sand , gravel, building stone, or metallic ore. Early mining concentrated on the richest lodes of minerals . Because modern methods of mining are more efficient, they can extract the desired minerals from veins that are less rich. However, much more waste is produced in the process. Many of the plant and animal wastes generated by agriculture remain in the fields or rangelands. These wastes can be beneficial because they return organic matter and nutrients to the soil. However, modern techniques of raising large numbers of animals in small areas generate huge volumes of animal waste, or manure. Waste in such concentrated quantities must be managed carefully, or it can contaminate groundwater or surface water. Industrial wastes that are not hazardous have traditionally been sent to landfills or incinerators. The rising cost of disposal has prompted many companies to seek alternative methods for handling these Wastes, such as Waste prevention and recycling. Often a manufacturing plant can reclaim certain east materials by feeding them back into the production process. Hazardous wastes are materials considered harmful or potentially harmful to human health or the environment. Wastes may be deemed hazardous because they are poisonous, flammable, or corrosive, or because they react with other substances in a dangerous way. Industrial operations have produced large quantities of hazardous waste for hundreds of years. Some hazardous wastes, such as mercury and dioxins, may be released as gases or vapors. Many hazardous industrial wastes are in liquid form. One of the greatest risks is that these wastes will contaminate water supplies. An estimated 60% of all hazardous industrial waste in the United States is disposed using a method called deep-well injection. With this technique, liquid wastes are injected through a well into an impervious reconfirmation that keeps the waste isolated from groundwater and surface water. Other methods of underground burial are also used to dispose hazardous industrial waste and other types of dangerous material. Pesticides used in farming may contaminate agricultural waste. Because of the enormous volumes of pesticides used in agriculture, the proper handling of unused pesticides is a daunting challenge for waste managers. Certain mining techniques also utilize toxic chemicals. Piles of mining and metal-processing waste, known as waste rock and tailings, may contain hazardous substances. Because of a reaction with the oxygen in the air, large amounts of toxic acids may form in waste rock and tailings and leach into surface waters. Public attitudes also play a pivotal role in decisions about waste management. Virtually every proposed new landfill or waste-to-energy plant is opposed by people who live near the site. Public officials and planners refer to this reaction as NIMBI, which stands for Not In My Backyard If an opposition group becomes vocal r powerful enough, a city or county council is not likely to approve a proposed waste-disposal project. The public also wields considerable influence with businesses. Recycling and waste prevention initiatives enjoy strong public support. About 19% of United States municipal solid waste was recycled or composted in 1 994, was incinerated, and 71 % was landfill. Preventing or reducing waste is typically the least expensive method for managing waste. Waste prevention may also reduce the amount of resources needed to manufacture or package a product. For example, most roll-on deodorants once came in a plastic bottle, which was inside a box. Beginning about 1 992, deodorant manufacturers redesigned the bottle so that it would not tip-over easily on store shelves, which eliminated the need for the box as packaging. This is the type of waste prevention called source reduction. It can save businesses money, while also reducing waste. Waste prevention includes many different practices that result in using fewer materials or products, or using materials that are less toxic. For example, a chain of clothing stores can ship its products to its Stores in reusable garment bags, instead of disposable lactic bags. Manufacturers of household batteries can reduce the amount of mercury in their batteries. In an office, employees can copy documents on both sides of a sheet of paper, instead of just one side. A family can use cloth instead of paper napkins. Composting grass clippings and tree leaves at home, rather than having them picked up for disposal or municipal composting, is another form of waste prevention. A resident can leave grass clippings on the lawn after mowing (this is known as grass-cycling), or can compost leaves and grass in a backyard composting bin, or use them as a mulch in the garden. When the current recycling boom began in the late sass, markets for the recyclables were not sufficiently considered. A result was that some recyclable materials were collected in large quantities but could not be sold, and some ended up going to landfills. Today, the development of recycling markets is a high priority. Close the loop is a catch-phrase in recycling education; it means that true recycling (I. E. , the recycling loop) has not taken place until the new product is purchased and used. To boost recycling markets, many local and state governments now require that their own agencies purchase and use products made from cycled materials. In a major step Fontana for recycling, President Bill Cloudiness an executive order in 1993 requiring the federal government to use more recycled products. Many managers of government recycling programs feel that manufacturers should take more responsibility for the disposal of their products and packaging rather than letting municipalities bear the brunt of the disposal costs. An innovative and controversial law in Germany requires manufacturers to set up collection and recycling programs for disused packaging of their products. The high cost of government-created recycling programs is often criticized. Supporters of recycling argue it is still less expensive than landfill or incineration, when all costs are considered. Another concern about recycling is that the recycling process itself may generate hazardous wastes that must be treated and disposed. Recycling of construction and demolition (CD) debris is one of the growth areas for recycling. Although CD debris is not normally considered a type of municipal solid waste, millions of tons of it have gone to municipal landfills over the years. If this material is separated at the construction or demolition site into separate piles of concrete, wood, and steel, it can usually e recycled. Composting is considered either a form of recycling, or a close relative. Composting occurs when organic waste-? such as yard waste, food waste, and paper-?is broken down by microbial processes. The resulting material, known as compost, can be used by landscapers and gardeners to improve the fertility of their soil. Yard waste, primarily grass clippings and tree leaves, makes up about one-fifth of the weight of municipal solid waste. Some states do not allow this waste to be disposed. These yard-waste bans have resulted in rapid growth for municipal composting programs. In these orgasm, yard waste is collected by trucks (separately from garbage and recyclables) and taken to a composting plant, where it is chopped up, heaped, and regularly turned until it becomes compost. Waste from food-processing plants and produce trimmings from grocery stores are composted in some parts of the country. Residential food waste is the next frontier for composting. The city of Halifax, in Canada, collects food waste from households and composts it in large, central facilities. Biological treatment, a technique for handling hazardous wastes, could be called a high-tech form of composting. Like composting biological treatment employs microbes to break down wastes through a series of metabolic reactions. Many substances that are toxic, carcinogenic (cancer-causing), or undesirable in the environment for other reasons can be rendered harmless through this method. Extensive research on biological treatment is in progress. Genetic engineering, a controversial branch of biology dealing with the modification of genetic codes, is closely linked with biological treatment, and could produce significant advances in this field. Waste management became a particularly expensive proposition during the 1 9905, especially for disposal. Consequently, waste managers constantly seek innovations that will improve efficiency and reduce costs. Several new ideas in land-filling involve the reclamation of useful resources from wastes. For example, instead of just burning or releasing the methane gas that is generated within solid-waste landfills, some operators collect this gas, and then use it to produce power locally or sell it as fuel. At a few landfills, managers have experimented with a bold but relatively untested concept known as landfill mining. This involves digging up an existing landfill to recover recyclable materials, and sometimes o re-bury the garbage more efficiently. Landfill mining has been criticized as costly and impractical, but some operators believe it can save money under certain circumstances. In the high-tech world of incineration, new designs and concepts are constantly being tried. One waste-to-energy technology for solid waste being introduced to the United States is called fluoride-bed incineration. About 40% of incinerators in Japan use this technology, which is designed to have lower emissions of some air pollutants than conventional incinerators. A 1 994 United States Supreme Court ruling could increase the cost of incineration significantly. The Court ruled that some ash produced by municipal solid-waste incinerators must be treated as a hazardous waste, because of high levels of toxic substances such as lead and cadmium. This means that incinerator ash now has to be tested, and part or all of the material may have to go to a hazardous waste landfill rather than a standard landfill. A much smaller type of incinerator is used at many hospitals to burn medical wastes, such as blood, surgical waste, syringes, and laboratory waste. The safety of these medical waste incinerators has become a major issue in some communities. A study by the Environmental Protection Agency released n 1 994 found that medical waste incinerators were leading sources of dioxin emissions into the air. The same study warned that dioxins, which can be formed by the burning of certain chemical compounds, pose a high risk of causing cancer and other health hazards in humans. The greatest impetus for waste prevention will likely come from the public. More and more citizens will come to understand that pesticides, excessive packaging, and the use of disposable rather than durable items have important environmental costs. Through the growth of the information society, knowledge about these and other environmental issues will increase. This should result in a continuing evolution towards more efficient and environmentally sensitive waste management. Waste management is the collection, transport, processing or disposal, managing and monitoring of waste materials. The term usually relates to materials produced by human activity, and the process is generally undertaken to reduce their effect on health, the environment or aesthetics. Waste management is a distinct practice from resource recovery which focuses on delaying the rate of consumption of natural resources. All waste materials, whether they are solid, liquid, gaseous or radioactive fall within the emit of waste management. Waste management practices can differ for developed and developing nations, for urban and rural areas, and for residential and industrial producers. Management of non-hazardous waste residential and institutional waste in metropolitan areas is usually the responsibility of local superconductivitys, while management for non- hazardous commercial and industrial waste is usually the responsibility of the generator subject to local, national or international authorities. Waste collection methods vary widely among different countries and regions. Domestic waste collection services are often provided by local government authorities, or by private companies in the industry. Some areas, especially those in less developed countries, do not have a formal waste-collection system. Examples of waste handling systems include: In Europe and a few other places around the world, a few communities use a proprietary collection system known as Invade, which conveys refuse via underground conduits using a vacuum system. Other vacuum-based solutions include the [emailprotected] [3] single-line and ring-line automatic waste collection system, here the waste is automatically collected through relatively small diameter flexible pipes from waste collection points spread out up to a distance of four kilometers from the waste collections stations. In Canadian urban centers curbside collection is the most common method of disposal, whereby the city collects waste and/or recyclables and/or organics on a scheduled basis. In rural areas people often dispose of their waste by hauling it to a transfer station. Waste collected is then transported to a regional landfill. In China, Plastic paralysis or Tire paralysis is: the process of converting waste lactic/tires into industrial fuels like paralysis oil, carbon black and hydrocarbon gas. End products are used as industrial fuels for producing heat, steam or electricity. Paralysis plant is also known as: paralysis unit, plastic to fuel industry, tire to fuel industry, plastic and tire recycling unit etc. The system is used in USA California, Australia, Greece, Mexico, the united Kingdom and in Israel-For example, REESE paralysis plant that has been operational at Texas USA since December 2011, and processes up to 60 tons per day. [J In Taipei, the city government charges its households and industries for the volume of rubbish they produce. Waste will only be collected by the city council if waste is disposed in government issued rubbish bags. This policy has successfully reduced the amount of waste the city produces and increased the recycling rate. In Israel, the Arrow Ecology company has developed the Aerobic system, which takes trash directly from collection trucks and separates organic and inorganic materials through gravitational settling, screening, and hydro-mechanical shredding. The system is capable of sorting huge volumes of solid waste, salvaging recyclables, and running the rest into biogas and rich agricultural compost.

Do not shoot, it shouted

`Do not shoot, it shouted `I am a B-b-british object!. These are the first words spoken by the main character Gemmy in the novel Remembering Babylon. Gemmy Fairley enters the environment of a distant Australian settlement having spent 16 years of his life living with the aborigines. He has lost contact to his past British background, to his language and cultural identity. In the Scottish settlement his past identity begins to reconstruct itself piece by piece, word by word. He struggles with familiar English words until whites avert their eyes, seeing in his search for simple sounds a sign of impairment or worse, of treason. In any case, it is a mark of otherness that subverts the settlers own identity. Gemmy compels them to ask themselves "Could you lose it? Not just language but it. It." (40) 16 years ago Gemmy was a "British object", he was still a boy until British seamen heaved him overboard near the coast of Australia sometime in the middle of the 19th century. Then he became an aboriginal object. Gemmys presence in the village makes the hardest men among them harder still. His indistinctness, his being neither one thing nor the other, in age, culture or appearance, his different consonants and different vowels seems more than imbecilic to the settlers, it seems monstrous. If his existence can be resolved at all in their minds it is that he must be a "blackfeller" disguised in white skin, a dangerous emissary of the outback. In unmasking themselves from the illusion of cultural objective truth, they would make progress and elevate the human nature. In the closeness of the settlers Gemmy tries to find his language and core identity, "It was as if the language these people spoke was an atmosphere they moved in. Just being in their proximity gave him access to it." (14) Gemmy believes that the words spoken by the settlers are the key to his lost language, and if he only c...

HOW ARE FASHION AND APPEARANCE CENTRAL TO THE CONSTRUCTION OF SOCIAL Essay

HOW ARE FASHION AND APPEARANCE CENTRAL TO THE CONSTRUCTION OF SOCIAL IDENTITIES DISCUSS, WITH REFERENCE TO SPECIFIC EXAMPLES - Essay Example In understanding beauty and the sacrifices that are made for representing what is beautiful, it can be seen that most cultures have supported alterations of the body in order to attain the essence of beauty as it is defined within the social construct, creating identity and status through those sacrifices. The value of beauty is so high that great pain has been endured in order to attain that representation The concept of beauty would seem a simple concept to define, however beauty is sociologically relevant to the culture that defines it and has an evolving meaning that changes through time. At the center of modern Western society is the beauty salon. According to Black (2004), â€Å"The beauty salon stands at the intersection of a number of techniques of the body, which in turn relate to gender, the body, sexuality, class, commodification, leisure practices, consumption, and so on† (p. 7). Current Western society also supports the use of painful surgical remedies to alter th e physical form and create a more beautified appearance. However, pain has been collateral to many of the ways in which beauty has been chased throughout the centuries. While contemporary society may frown upon some of the methods that have been used throughout history, the current trends are actually a continuation of culturally accepted concepts of the discomfort and pain that can be experienced in the pursuit of what is physically beautiful. The Beauty Salon in Western Society The core of the creation of beautiful through physical change within contemporary Western society is the beauty salon, a place where the hair, skin, and nails are attended to in order to project a more beautiful exterior presence. The salon is a social center, as much as it is a utilitarian entity. According to Black (2004), as she quotes Yvette, an owner of a salon, â€Å"Ordinary people come through here The desire of these ‘ordinary people’ is for pleasure and escapism† (p. 2). While what is done there occurs in order to emerge into society with the intention of the results having an impact on the way in which one is viewed, what happens within the salon is as much a part of the identity as the effect of the result. A relationship is developed between the staff and the client, a connection that is made in order to form a social contract where the professional expertise of the staff member becomes the center of the development of an intimacy with the client, the commodified relationship as emotional as it is purposeful. Often the relationship that one has to their beauty professional is as much emotionally therapeutic as it is physically therapeutic (Black 2004, p. 7). What occurs within the salon is often uncomfortable, if not painful, that level of suffering helping to form the bond between the beauty professional and the client. What is experienced and sacrificed in order to attain the result helps to create the intimacy through which the social contract is es tablished. Furthermore, there is a sexuality that is established within the confines of the experience. The salon professional often must inflict pain in a very intimate way in order to achieve the goals of the session. The pain is endured, the recipient developing a dependency on the one inflicting pain as the release of that sensation is within the control of the professional. This pain can become a deep resource of connectivity between the one inflicti

The Roman Fever Essay Example | Topics and Well Written Essays - 1000 words

The Roman Fever - Essay Example Background Essentially, the story was about the friendship of two women, Grace Ansley and Alida Slade. They were vacationing in Rome with their daughters, Barbara Ansley and Jenny Slade. This was the second time that the two elderly women had been to the city. They had previously visited Rome and the present travel provided a conducive for the two protagonists to reflect on their lives. A good part of it came as offshoot of what transpired in Rome many years ago. As they looked back on the past, a secret was revealed by Mrs. Slade amidst the long rivalry that hounded their friendship through the years. There was some sort of love triangle between Grace, Alida and her husband Delphin Slade in the past. It turned out that Mrs. Slade wrote a fake letter to Mrs. Ansley that supposedly came from Delphin Slade. The letter invited Grace to a tryst in the Coliseum in an effort to break her heart and cease getting in the way between Alida and Delphin as a consequence. It turned out that the t ryst actually transpired with Grace and Delphin meeting each other after the former revealed that she answered the letter and Delphin actually came. Strong Competing Women The story was a convoluted affair, but typical of the experience of the women of the American upper class during the 1930s. What makes this theme remarkable is that the story was controlled throughout by female protagonists, which depicted strong female roles. Certainly, the story was dominated by the two women and, then, there were their daughters, playing minor parts. The only physically present male in the narrative was the Italian waiter and some unseen Italian suitors who, from the statements of the protagonists, can be considered as objects of the predatory desires of their children. When the husbands were finally mentioned, they were referred to in passive roles or as tools in making a make a point, introducing an argument, and issue or a narration of experience. Mr. Horace Ansley was brought up by the two women only to be referred to as dull, spineless, boring and insufferably passive character – â€Å"just a duplicate of his wife† (12). It was obvious that his wife dominated him throughout their married life. Meanwhile, Delphin Slade was only introduced when the letter was brought up. Here, he was a facilitator or a device, if you may, in order for the desired reaction in the case of the letter to be effective. They are not unlike the Italian lovers previously mentioned. They were objects of the female rivalry and female negotiations as they navigated their relationships and pursued their objectives. They were there for a reason and such reason was determined by the women who need their respective resources and ammunition to outdo each other. There are some subtle hints provided by Wharton to support the above point of view. Delphin closely resembles the word "delphic" which is synonymous to ambiguousness and obscurity. The name Delphin may also be related to the Roman Apollo, who was the god of light and represents manly beauty. So Delphin was like the trophy - the object - by which Grace and Alida and their mothers, before them, worked hard to achieve. From the very first words of the story, this tone was already established: â€Å"the women, ladies of ripe but well-cared for middle age moved across the lofty terrace of the Roman restaurant... looked first at each other, and then down on the outspread glories of the Palatine... with the same expression of vague but

A brief history of diving Essay Example for Free

A brief history of diving Essay For those who can swim, diving in the sense of scuba diving or deep sea diving is certainly one of the most enjoyable pastimes a person can have. Like anything else, it has its pleasures and its risks, but the allure of the sea is certainly a major part in the life of any avid diver. Still, diving has its risks and perhaps in some sense those risks are greater than in other endeavors. The allure of the sea and the desire to enjoy it as freely as a fish is irresistible to many. Our fascination with the oceans may have made diving popular in the 19th century, but if so, it was certainly made more popular by the introduction of scuba equipment in the middle of the 20th century. Despite the relatively recent development of deep sea diving apparatus and of scuba diving, men and women have been diving for centuries. Often diving is for pleasure, but at other times it is just another basic survival skill to gather food, hunt for sponges (Hong et al. , 1991) or engage in military endeavors or otherwise. Until the invention of diving equipment, man was unable to go underwater and remain submerged for any extended period of time. His stay under water was limited by his ability to hold his breath so the problem was how to extend the amount of time underwater and, of course, the obvious solution was to find a means to provide an air supply to a submerged person. In August of last year (2006) while testing the Navys new Atmospheric Diving System (ADS) suit off the coast of La Jolla CA, a village of San Diego, Daniel Jackson, a Naval Reserve Diver, made the deepest free dive in history, a total of 2,000 feet. (Guinness, 2006) Perhaps it is because of the allure of the sea, but long before Jackson, men and women practiced breath-holding. Diving has many useful purposes such as gathering and providing food, military, recreational, research and others so these factors have no doubt added to the allure of diving. Despite the relatively new advent of scuba equipment and deep sea diving equipment, diving has been around for a long time. Of course, it is necessary to hold ones breath in order to go to any great depth and people have been using breath-holding techniques for diving for centuries. In ancient Greece, divers held their breath to search for sponges as some people do today, and throughout history some had done likewise in the process of military exploits. For those who wanted to stay underwater longer, the obvious question was how to do so? One solution was to breathe through hollow reeds while submerged. While this technique worked, there were limitations that prohibited it from being a valuable solution. Reeds longer than two feet long do not work well. Today we realize that it is difficult to inhale against water pressure below a certain depth. Another idea was to put air into a bag that could be used underwater, but that also presented problems, most significantly the fact that it caused divers to breathe in the carbon dioxide that had been exhaled. Although Aristotle wrote about a diving bell in the 4th century BC, all diving was probably done by holding the breath up until the 16th century. (Brylske, 1994; Somers, 1997) Whatever diving was done probably did not exceed depths of 100 feet if that much. The diving bell was the predominant diving apparatus during the 22 centuries from the 4th century BC until the around 1800. Using this stationary device, divers could get air from the bell and leave to do whatever they were doing underwater returning to the bell periodically for more air. This allowed divers to remain underwater until air in the bell was no longer breathable. By the 16th century, people began experimenting with diving bells. (Somers, 1997) These were actually bell shaped contraptions open at the bottom that were held a few feet from the surface. The diver could enter from the bottom which was open to water and the top part held compressed air, air that had been compressed by the water pressure. Early designs of the diving bell were refined in the late 1600s and became sizable and sophisticated by 1691 when Edmund Halley patented a ventilated diving bell that allowed divers to remain underwater for as much as an hour and a half. (Gilliam and von Maier, 1992) Even though electricity was not available for electric pumps at that time, manual pumps were used that could pump air from the surface down to divers as early as the 16th century in Europe. However, at greater depths, water pressure became a concern, so metal helmets and leather full diving suits were developed and used to protect divers who went below 60 feet. This diving equipment was continuously perfected up to the 19th and 20th centuries. By the 1830s, diving techniques that relied on air pumped to divers from the surface had been sufficiently well developed as to allow divers to work underwater for extended periods of time. Although these early techniques worked, they didnt entirely compensate for some diving concerns. Eventually, the improved technology of the 19th century resulted in compressed air pumps, regulators, carbon dioxide scrubbers and other improvements that allowed divers to remain underwater for longer and longer periods of time. As diving techniques improved, it became more apparent that there were at least two concerns in diving to depth. One, of course, was the need for an air supply that would eliminate the need to hold ones breath. The other problem was the need to compensate for depth. (Brylske, 1994; Somers, 1997) In 1905 Scotlands John Scott Haldane reported the fundamental discovery that breathing is regulated by the amount of carbon dioxide in the blood and in the brain. Haldane developed a method of decompression in stages that allowed deep-sea divers to ascend to the surface safely, information used for todays decompression charts. His work and that of the French physiologist Paul Bert increased our understanding of the physiological effects of air-pressure sufficiently to improve out knowledge of the hazards of diving to depth and how to overcome those hazards. Our understanding of the effects and safe limits of using compressed air for diving is due largely to the work of Haldane and Bert. (Gilliam and von Maier, 1992) Today, we realize that decompression, recompression, carbon dioxide and oxygen toxicity are important factors to consider in diving. Diving history can essentially be divided into four periods. Initially, there was the period of free diving when humans held their breath. Diving time and diving capacity were limited by the availability of air, the build-up of carbon dioxide and the effects at depth of pressure on the body. (Gilliam and von Maier, 1992) Later advances in diving during the second period of diving history led to the creation of heavy walled diving vessels which could maintain their internal atmosphere to that of sea level (1 atmosphere) so as to prevent the surrounding water pressure from being a hazard to the occupants. Diving bells and bathysphere are two such devices. Bathyspheres are essentially unpowered hollow steel balls that can be lowered from a mother ship by a steel cable. A bathyscaphe is a is bathysphere with a buoyancy control that eliminates the need for a cable. Then there is the submarine, a powered device with its own air supply and which is built so that it can handle all of the problems associated with depth and so it can travel great distances in any direction under its own power. Bathyspheres, bathyscaphes and submarines required a means to maintain the pressure at one atmosphere around the diver and a means to provide fresh oxygen while getting rid of exhaled carbon dioxide. Carbon dioxide was eliminated by using soda lime, lithium hydroxide and other compounds that take up the carbon dioxide. Later during this period, one atmosphere diving suits were also developed that were flexible and yet able to withstand pressures at great death so as to allow divers to work at depths up to several hundred meters for hours. (Somers, 1997) Diving entered a period of using compressed air next. The air could be supplied from the surface and delivered to the diver at depth. The hand-operated air compressor was a major advancement in diving history. It had appeared by 1770 and allowed for the development of helmet-hose diving systems that were the predominant diving techniques from 1800 until the mid-1950s. Unlike then final period, during this period of diving the diver is separated from his/her air supply, but has air delivered through a long umbilical cord to a regulator and mouthpiece carried by the diver. At great depth, the diver can be enclosed in a dive suit that can handle the water pressure at depth. These suits can be cumbersome but the buoyancy of the water can relieve some of their burden. Although diving masks with a regulator, mouthpiece and hose may come to mind when one considers these devices, caissons are also included in this category. Caissons are huge spaces that are supplied with compressed air. Diving bells and rigid helmet diving suits are also grouped in this category. The air that the diver breathes is at the same pressure as that of the water surrounding the diver thus leaving him at risk for decompression concerns such as the bends, air embolism, etc. pon their ascent if they ascend too fast. To assist with this concern, special mixtures of gas are used that allow divers to dive deeper than with compressed air. These gas mixtures combine oxygen with another gas or gases such as hydrogen, helium and/or nitrogen. (Somers, 1997; Gilliam and von Maier, 1992) The most recent development in diving is diving with compressed air or gas mixtures that include oxygen carried by the diver. This is referred to by the acronym S. C. U. B. A. which is generally referred to as scuba diving. Scuba stands for self contained underwater breathing apparatus and refers to the fact that the diver carries his or her air supply on their back while diving. Although we may view scuba gear to be a recent development in diving technology, the development of scuba gear can be traced back to 1680 when Borelli, who also experimented with fins and buoyancy compensation, developed a device based on the theory that the hot air a diver exhales could be rejuvenated by cooling and condensing in. (Somers, 1997) Although Borellis gear failed, it still represents a step forward in diving theory and technology. By the first third of the nineteenth century, Condert published a scuba design using a helmet and a compressed air reservoir that fit around the divers waist. In 1865, Rouquayrol developed a surface-supplied regulator system that did ultimately have an effect on todays scuba gear. By 1878, Fleuss and Davis developed a closed-circuit oxygen scuba device that used chemical carbon dioxide as absorbent. (Gilliam and von Maier, 1992; Somers, 1997) The scuba equipment commonly used today was developed by Emile Gagnan and Jacques-Yves Cousteau. Somers, 1997; Cousteau, 1986; Marx, 1990) The two principle types of scuba equipment are open circuit and closed circuit equipment. Open circuit equipment vents the expired air into the water while closed circuit systems all the carbon dioxide to be absorbed and add more oxygen so that the air can be re-used. Scuba divers are at risk for decompression problems if they ascend too fast and various gas mixtures allow scuba divers to go deeper than with compressed air. Scuba diving has a number of advantages over other forms of diving. The tanks allow the diver to remain underwater longer than would be possible by simply holding ones breath. Even though scuba allows divers to go deeper than with snorkeling and allows them more freedom than would be possible using compressed air from the surface, its major disadvantage is that the time spent underwater is limited by the amount of compressed air in the tanks. Since time is of essence and all muscle activity decreases the amount of time that oxygen will be available, scuba divers can increase the amount of time they will have underwater with scuba gear if they exert less energy while diving. Although most divers swim underwater while diving, they can resort to propulsion devices referred to as Diver Propulsion Vehicles (DPVs) commonly called scooters to move underwater. The term SCUBA originally referred to rebreathers used by the military for underwater warfare but today it generally refers to open-circuit equipment. However, rebreathers are also classified as scuba gear. The history of diving is certainly to complex and exciting to cover in these few pages, but what few comments have been presented do demonstrate how rich that history is and how far it extends back in time. Only by considering how far back into history diving extends and the advances diving has made with the passage of time will we truly realize the fascination diving has held for us through time. Perhaps the next great advance in diving will not be man growing gills, but whatever it will be will only add to the present fascination and allure of diving. We can only build on the future of diving by understanding how we arrived at our present level of knowledge and technology.

When Will It End? :: essays research papers

You may heard of me in ancient history. I am Genghis Khan and I,would like to share a story that was not recorded in history.In 1199 near the middle of winter,on the northern borders of china. My two best men and I were left standing,after being at war with the mongolians for several weeks,filled with hunger and dressed with wounds decided to retreat to home to heal and gather more men. I yelled lets go,We lofted on our horses,and right at that moment,a loft of arrows desended,up on all three of us killing my two men,and leaving me wounded in the arm, i broke the shaft of the arrow,and pulled it out,flung it on the ground and dug my spurs into my horses flesh,and like a bolt of lighting we shot through the woods.I knew my horse was weak, not having much to eat,but some bark off the trees,because of the heavy snow, my prayers were to the effect,that i would be home soon. I could hear hoof beats off in the distance,they sounded like they were getting closer, all i had on my mind was d arkness.Once dark my chances of escape are far better,I was still bleeding and felt like my horse was about to give up,as we arrived at the top of the mountain,looking down the other side and down at the bottom was a long winding river,i knew this was my escape,my horse collapsed to its side,gave his last breath.At that moment i heard a branch break,looking over my shoulder,gettig closer was that small army,of mongolians,run,run,run was going through my mind,i was weak and could not move very fast.i could here the words of the savages,bragging about how much my head was worth,then i slipped on the hard snow hit my head

Money Is the Root of All Evil

Money is the root of all evil. Many of us grew up hearing that money is the root of all evil, but that is not really what scripture teaches us. Money is neither evil nor good. It is only what happens with money once it is in our hands that gives it qualities of either good or evil. Money can be many things, depending on how we relate to it. We need to understand the difference between a physical currency that is the basis for our lives and a material desire that is driven by greed. It is a fact that money makes the world go round and this is how we bargain for food, shelter, education, travel and just about everything in life has a price.Money is the reward for our work that allows us to enjoy the good things in life. It is the foundation for our social organizations and the donations to churches and charitable organizations that allows them to become established and function properly within our communities. From this point of view, money is not the evil; it is just a source of our s urvival. From the other hand, the love of money can destroys our lives. Not only money by themselves, but the desire of them. The greediness can destroy individuals, break up homes and even bring down nations.When the love of material possessions, social status and political power are the driving force behind our desire for money, we become rooted in evil. People can also make money there god. It depends on whether money is in control of the person or the person is in control of the money. It is clear, when money is in control of person it can make a lot of harm. To sum up, I should say that money is not evil, as I think. It's just the greed that's in the hearts of those who want it for needless riches and power that gives money the label of being evil.