Why I want to be an HR Generalist Essay Example | Topics and Well Written Essays - 250 words

Why I want to be an HR Generalist - Essay Example I qualify for this job also because I have about 18 months of experience of working as an HR Generalist with a company where I was required to manage the day-to-day operations, manage employee relations, administer the policies, programs, and procedures, arrange training and development programs for the employees, and address their individualistic and collective issues by serving as a medium of coordination between them and the top management. One thing that I love about working as an HR Generalist is that it involves a lot of strategic management. The HR Generalist has to manage things in a way that generates positive messages for the organizational personnel so that they feel intrinsically motivated to cooperate and be a part of the change. I look forward to this opportunity so that I can apply the concepts I gained through years of training and practical experience.

Contributors of the Periodic Table of Elements Essay Example for Free

Contributors of the Periodic Table of Elements Essay The First International Congress of Chemists took place in September 1860 in Karlsruhe, Germany to review scientific matters that there was little agreement to. Following this congress led to the development of the periodic table of elements. Top contributors to the periodic table included Staislao Cannizzaro, Dmitri Mendeleev, Henry Gwyn-Jeffreys Moseley, John William Strutt, William Ramsay, Friedrich Ernst Dorn, and Glenn Seaborg. Stanislao Cannizzaro, born in 1826 and died in 1910, was an Italian chemist. He presented a method to measure atomic masses and to interpret the results of the measurements. Cannizzaro’s method aided scientists into agreeing standard values for atomic masses. The scientists then searched for relationships among atomic masses and other properties of the elements. Dmitri Mendeleev, born in 1834, was a Russian chemist, and is sometimes considered as the ‘father of the Periodic Table’. Mendeleev was in the process of writing a chemistry textbook and he wanted to organize the elements according to their properties. Mendeleev created a table where elements with similar properties were grouped together. Mendeleev’s table left several empty spaces because there were elements that had not been discovered yet. Then in 1871, Mendeleev predicted the existence and properties of three elements. His predictions were a success and it led to scientists accepting his periodic table. Henry Gwyn-Jeffreys Moseley, born in 1887, was an English scientist that discovered that atomic number, not atomic mass, was the basis for the organization of the Periodic Table. Moseley and Rutherford performed multiple experiments on 38 metals and Moseley discovered a pattern in which the positive charge of the nucleus increased by one unit from one element to the next when the elements are arranged as they are in the Periodic Table. His studies also led to the modern definition of atomic number and it provided justification for Mendeleev’s ordering of the Periodic Table by properties rather than just by atomic mass. Mendeleev’s Periodic Table did not include noble gases because at that time it was not discovered then. The English physicists John William Strutt and William Ramsay discovered four of he noble gases. Argon and helium were discovered by the two scientists in 1894. To fit argon and helium into the table, they proposed a new group that was placed between Group 17 and Group 1. Then, krypton and xenon were discovered by Ramsay in 1898. Radon, the final noble gas, was discovered in 1900 by a German scientist named Friedrich Ernst Dorn. Glenn Seaborg was an American scientist and he discovered all the transuranic elements from 94 to 102. With this discovery, he was the last person to majorly change the Periodic Table by placing the actinide series below the lanthanide series.

Chipset Summary Report :: Essays Papers

Chipset Summary Report Dear Manager Please find attached our submission for your Invitation for offer for a motherboard to meet the specifications supplied. This report supplies details of all required specifications. Please do not hesitate to contact my office if you should have any questions regarding this offer. Executive Summary "Your Name Here" Computers is proposing to deliver a comprehensive solution to the Ajax Computer Company both to address your immediate needs as well as to provide a platform for future development. As one of the world’s leading providers of computer hardware and networking equipment, "Your Name Here" Computers is focused on providing the Ajax Computer Company with a solution focused on delivering:  High quality products which translates into low cost of ownership over the entire life of the equipment – this saves you money  A state of the art solution helping you to keep your network on the air – this provides you with the ability to deliver the best to your staff  A scalable solution with no need to make major equipment replacements when you need more features or capacity – this saves you money  A high performance solution – this minimises your staff waiting around for â€Å"the computer† The MS-5184 motherboard proposed by "Your Name Here" Computers is based on a product that has been shipping for a substantial period of time and has many reference sites both in Australia and globally. "Your Name Here" Computers are prepared to conduct a proof of concept with you on short notice to demonstrate our MS-5184 motherboard solution. We appreciate that Ajax Computer Company has limited exposure to "Your Name Here" Computer technologies. In order to address this issue and demonstrate to you the friendly and professional approach of "Your Name Here" Computers we have provided the following reference material as per your request: Year 2000 Compliance Dear Customer: For all "Your Name Here" Computer products with a Year 2000 readiness status of "YES" and operating at the stated minimum software level specified on the "Your Name Here" Computer.com web site; "Your Name Here" Computers provides the following Year 2000 Warranty. ""Your Name Here" Computer Corporation" warrants that "Your Name Here" Computer Products (hereinafter 'Products') that are date sensitive which have been sold or licensed to Customer will continue performing properly with regard to such date data on and after January 1, 2000, provided that all other products used by customer in connection or combination with the "Your Name Here" Computer Products, including hardware, software, and firmware, accurately exchange date data with the "Your Name Here" Computer Products.

Farms to Cities

For most American’s, lifestyles changed dramatically for those who were used to living on the farm. Farmland started changing to the urbanization of the cities from the late 1860’s to the 1920’s. Due to the mass increase of immigration, both the â€Å"Old Immigration† and the â€Å"New Immigration† gained new opportunities due to the Second Industrial Revolution. This included the introduction new technology and innovations, and the creation of factories and the assembly line and mass production, and a new urbanized lifestyle. The city became a new and worthy opportunity for those who formerly worked on a farm. By 1925 the city, and not the farm, had become the basic reality for most Americans because of the Second Industrial Revolution, the mass immigration, and the opportunity for greater wages. The Second Industrial Revolution is considered to have begun in the 1860’s. New technologies and innovations such as the Bessemer steel converter, the internal combustion engine, the production and refining of oil and gasoline, the telegraph, the radio, electricity and the American system of manufacturing were created in the mid to late 19th century. The Bessemer converter worked by blowing air through holes at the bottom of the convertor to create a reaction that oxidizes the silicon and excess carbon which converted it to pure steel or iron. This machine allowed a lowered price on steel and iron as well as speed in production. This was a major contributor to the production of railroads. The expansion of the railroads greatly increased from 1860 to 1920. Railroads tripled from 1860 to 1880 and then doubled again by 1920. The railroads lowered the cost of shipping which enabled the cheaper movement of raw materials that would be used in factories. These new tracks also connected isolated towns to larger markets which allowed them access to new materials they could not have before. Larger cities had an expansion of better transportation systems, such elevated railways and subways and road way systems for the bicycle craze of the 1890’s. These innovations introduce in the 1880’s such as the American system of manufacturing substantially increased the productivity in the sewing and bicycle industries. A major development in the manufacturing methods of the Second Industrial Revolution was introduction of electricity to factories. This enabled the factories to utilize the new innovations of the assembly line and mass production. New Factories were starting to pop up in many cities in the Northeast sections of the United States. Since more and more factories were being built, they needed more and more workers to help run the factory and to keep it stable. These factories created many new job opportunities for those that were considered middle class. Wages were much higher compared to farming jobs and local small town jobs. There were two types of workers, skilled workers and unskilled workers. The skilled workers were very good at what they did and instructed the unskilled workers to perform simple task and to repeat it over and over again. This soon created the assembly line which helped the skilled worker get his job done faster since all the unskilled workers were helpingthe small task move along so the skilled worker could finish the project. Many of the unskilled workers were tired of repeating these motions and wanted to gain a skill set to become more valuable and earn higher wages. Therefore some of the first colleges were created to help teach these unskilled men new skill sets. Also, the workers in the factories created a new market demand for things such as housing, grocery stores, and department stores. Because of this new market demand, the US economy grew immensely from the late 1860’s to the 1920’s.

Prospects for the Future of Liberal Democracy in Libya

Following the death of the infamous former Libyan leader Colonel Muammar Qaddafi former Libyan leader, a lot of debates and concerns have been raised worldwide about the future of the nation. A range of issues from social, economic, religious and political are being raised and the big question seems to be, what next? After years of authoritarian rule and with the ‘enemy’ finally out of the picture, the Libyan government faces different prospects for its development and in this essay I will be looking at different possibilities for the nation in relation to the promotion of liberal democracy.Currently under a transitional government, Libya stands the chance to embrace change and adopt what may be considered by some as positive western ideals. According to a Freedom house report â€Å"another country that endured decades of brutal misrule, Libya, now has the potential for significant gains thanks to the overthrow of al-Qadhafi. † (Puddington, 2012) Democracy has at no other time in history been knocking at the doors of many political regimes and with voices calling not only from foreigners but also from indigenous citizens it would be very hard to ignore the relevance that democracy plays in our modern day society.Over the past year especially, the world has witnessed many political resistance campaigns; what is now popularly referred to as the Arab Spring has flooded the news very often and one common outcry from these people is the need for change. One might wonder what fuelled this uprising from the people to demand new leadership, in my educate d opinion, decades of authoritarian rule, human rights abuses, oppression on opposition and the inability of people to speak freely amongst others have all led to this desire for change. Before delving into the prospects for democracy in Libya, I feel it will be essential to underline what democracy entails.Robert Dahl in his book ‘On democracy’ lists various desirable features of a dem ocratic society as follows: †¢Control of military and police by elected officials. †¢Democratic beliefs and political culture †¢No strong foreign control hostile to democracy †¢A modern market economy and society †¢Weak subcultural pluralism (Dahl, 2005) Based on this it is fair to say that liberal democracy demands the inclusion of people, it believes in equality and fairness and encourages the notion of two (or many) heads being better than one.However it is also true that democracy is not the only route for stability, in reality â€Å"the highest risk of political crisis lies in the middle ground between authoritarianism and democracy† (Goldstone, 2005) I believe a democratic and representative government can be attainable in Libya despite being broken into various sects for close to fifty years. Both pro and anti Qaddafi forces can push Libya forward but as to whether this will mature fully into a liberal democracy is tricky. The prospects for Lib ya would look bleak especially when considered from the perspective of historical precedents.In the Libyan case, several factors cement this view. To begin with, Libya is a society filled with many different tribes. From what might be considered extreme Islamists, to the more moderate ones, to the presence of Christians and then other religious and secular divisions the presence of diversity in terms of culture or beliefs could either hinder or promote liberal democracy. In other parts of the continent, particularly sub-Saharan Africa, this situation has been witnessed before but â€Å"among the most important lessons to emerge is the importance of avoiding factionalism. (Goldstone, 2005) Take Rwanda for example, where Hutu’s and Tutsi rebels have shed blood over conflicting tribalistic views. In places where there is a vast difference in opinions, quite often people tend to disagree rather than agree and in order for democracy to prevail it is mandatory that people learn to compromise and agree for the better of the people. In the eastern part of the nation, we can find the current ruling rebels and in the West where Sirte is located there is a stronger presence of pro Qaddafi forces or loyalists. In order for democracy to take place it will take a combined effort from the North to South and East to West.A scholar who has engaged in different studies of transitional governments, Professor Michael Greig made several observations on the Libyan scenario, he bases his conclusions from his studies on transitions over the last 170 years of history and notes that the more diverse a society is, the less stable new regimes tend to be. (Coleman, 2011)With the murder of the former leader, the fear for this transition to be peaceful of fairly smooth is that loyalists might try to hold reprisal attacks, there could be various terror attacks even on innocent victims and militants, leaders, or officials under the former regime might strongly esist cooperating with t he new government and this will undermine attempts to achieve a sound and stable democratic environment. Should this occur, it could lead to an indefinite civil war and the country which already seems to be broken down into various fragments could end up losing more lives, it could also deter foreign investment and trade and regardless of the large oil reserve the country has, it could still have serious economic implications such as higher inflation rates.On the political front also, as to how confident citizens are in the government and how effect institutions being put in place will benefit the nation, only time will tell. Indeed Libyans have been shown a glimmer of hope since the death of their former leader however can they be guaranteed that another Qaddafi will not surface? â€Å"And while Libya has benefited greatly from the demise of the Qadhafi dictatorship, the country confronts an array of daunting political and security challenges, and has yet to hold its first electio ns†. Puddington, 2012)The Libyan people understandably seem to have trust issues in their new government and with this lack of trust, the people might not be too welcoming to the new rules or laws that might be put in place. Should they not have faith in the new government for too long they could be a coup d’Etat or some other form of uprising. Unrest could take place and this could just mean that democracy will fail yet again. Furthermore, there are serious doubts about how women, former members of the Qaddafi government and minorities will fare in the new order.The role of women is essential in achieving a liberal democracy. Women can be instrumental in broadening the parameters of democratic participation. They can challenge and sensitize others about the preconceived notions of what Islam can entail in a liberal democracy. For example, in Turkey, women activists achieved this to within the Islamist Refah (Welfare) Party. Libya has no democratic role models in the Ar ab world from whom to seek mentorship.One main factor that the people of Libya have going in their favour is the fact that when they finally decided to come out and rebel against their long term leader they were not influenced by the western nations or the international community as a whole. The effort was undoubtedly from within the very borders of the country and throughout the country there were many cries which eventually fell unto the ears of the international community. The freedom house report confirms this by stating â€Å"America’s firmness in assisting NATO’s Libyan campaign was an important step.After initial hesitation, the administration has also cautiously supported the process of building democratic systems in Tunisia, Egypt, and Libya. † (Puddington 2012) The Libyans did indeed capture and kill Muammar Qaddafi with the help of NATO forces however they initially started the movement and asked for help to take power away from Qaddafi. The significa nce of this is that there are dependency theorists for example who believe that the western world continues to infiltrate third world nations and prevents them from standing on their own but in this particular case that can be debunked.The issue of neocolonialism at least at the time that the uprising in Libya took place was arguably not present or wasn’t the main driving force and this means that the people of Libya do indeed have a voice of their own and will not be coerced into making policies or vital decisions presented to them by countries like the United Kingdom and United States of America. Liberal democracy therefore can eventually be introduced and maintained in a society like this where the people have a voice and do what they believe and agree together is best rather than allowing external forces to impose laws on them.Another positive factor about Libya which should well favour the nation is that due to its large oil reserves and the fact that they are a major ex porter of oil to different parts of the world, they have a more attractive economy as compared to others in the Arab spring. It is common for nations to establish and develop their political and democratic institutions before any significant change is seen in the economy, however the presence of an already good and healthy economy makes it fairly easier for the presence of democracy.The important thing here would be to have competent people in government to take key and important decisions and also to manage the resources of the nation well. When this is done and the citizens see an even better improvement in the economy it will build their confidence in the government and promote more civilian participation (a very important feature for liberal democracy). With higher literacy rates than other African nations (Puddington, 2012) and with the introduction of new laws for the land Libya in the future can definitely be a success story.To reiterate what has been mentioned above in this essay there is a fair possibility of the existence of a liberal democracy in Libya. It is important to note that â€Å"remarkably, after several years of assembling and sifting data , the panel found that economic , ethnic , and regional effect shave only a modest impact on a country’s risk of political instability. Rather, stability is overwhelmingly determined by a country’s patterns of political competition and political authority. (Goldstone, 2005). Although Libya is a country that is divided along tribal lines, it also has a good educated population and a decent economic growth. Research has shown that economic, regional and ethnic effects only have a modest effect on a country’s risk of political instability and â€Å"clearly, what â€Å"works† in establishing a stable democracy is moving toward a political system with completely open and fully competitive parties that maintains strong checks on executive authority. (Goldstone, 2005) Stability is hugely determined by the prevailing patterns of political authority and competition. The key to maintaining stability lies in the following 1. making democratic institutions that promote open and fair competition 2. Avoiding political polarization and factionalism 3. Imposing substantial measures against abuse of executive power Furthermore, wealth and few or no communal tensions help, but a country does not need wealth or a homogenous population to achieve stability.The fact of Libya having a well educated population also aids in its capability for liberal democracy. Educated people tend to hold liberal views and be more tolerant of divergent views. In the case of Libya, there exist factors that are in its favour in terms of achieving a liberal democracy. In addition, its oil reserves and a wealthy treasury are assets that can be used to build democratic institutions and improve capacity building in its current institutions. The enactment of laws that curb excesses by the executive will be huge boost in this direction.Thus, the prospects of democracy in Libya are not so bleak when considering its wealthy treasury and its small and talented population which have proven that they possess a voice to speak out for the promotion of a good agenda in Libya. Unlike poorer countries who may have to seek external funding to support their democratic initiatives, it need not do so. It has the necessary capital to start a wide range of socio-economic programs aimed towards a liberal democracy.For now, the rebel leaders seem to be receiving acceptable levels of support from the populace and this among other factors serve as crucial pointers that the prospects of a liberal democratic Libya are real. To conclude, we deduce from the above highlighted points that democratic development in Libya is faced with numerous challenges, political and economic, internal and external of long year’s authoritarian regimes, coupled with bad governance, fear of mismanagement of accum ulated capital and mass participation, non-conducive investor atmosphere and a shield from the West.At a minimum, the core elements of developing political democracy are: A strong, pluralistic civil society independent of state control and able to hold government accountable; Regular and effective mechanisms to choose and to change representatives, governments, and policies by non-violent means; wide dispersion of economic resources and state commitment to broadly distributed human development; The rule of law incorporating the principles of the supremacy of the law, equality before the law, and the impartial and fair administration of the law; Strong institutions and an international environment which supports, or at least not harmful to, the above element. This is what Africa and other emerging liberal democracies need in achieving political and economic development of this ‘new world order’ regime.

Quarry Sites - The Archaeological Study of Ancient Mining

Quarry Sites - The Archaeological Study of Ancient Mining To an archaeologist, a quarry or mine site is where a particular raw material- stone, metal ore, or clay- was mined in the past to be used to make stone tools, to carve blocks for building or statuary, or to make ceramic pots. Significance Some quarries used by ancient people were located near their point of use, regularly visited and fiercely protected from other groups as part of claimed territory. Other quarries, especially those for portable goods such as stone tools, were hundreds of miles away from the point of use, where the stone tools were found. In those cases, the people might have found the quarry on a hunting trip, made tools there and then carried the tools with them for a few months or years. Some high quality materials might also have been traded as part of a long distance exchange network. Artifacts made from far away resources are called exotic compared to local artifacts. Quarry sites are significant because they provide a wealth of information concerning the day-to-day living of people in the past. How well did a particular group understand and use the resources in their neighborhoods? How important was it for them to use high quality materials, and for what? How do we determine what a high quality resource means for an object or building? Questions Posed at Quarries At the quarry site itself, there might be evidence of the technical knowledge a society had about mining, such as the types of tools they used to excavate and shape materials. Quarry sites can also have workshops- some quarries were also production sites, where objects might be partly or completely finished. There might be tool marks on the outcrop showing how the workers pried the material out. There might be spoil heaps and discarded materials, which can illustrate what attributes that made a resource unusable. There might be encampments, where the miners lived while they were working. There might be inscriptions on the outcrops, such as notes about the quality of the material, or prayers to gods for good luck, or graffiti from bored miners. There could also be cart ruts from wheeled vehicles or other evidence of infrastructure suggesting how the material was transported to the point of use. The Challenge of Quarries Quarries are difficult to discover, because sometimes they are hard to see and scattered across the region. Outcrops of a particular source can cover many acres across a wide landscape. An archaeologist could find a stone tool or a pot or a stone structure at an archaeological site, but finding where the raw material to make that object or building came from is difficult, unless there are already quarries for that type of material that have been identified. Potential quarry sources can be found by using bedrock maps of the area, which are produced for the U.S. by the United States Geological Survey, and for the United Kingdom by the British Geological Survey: similar government-backed bureaus can be found for almost any country. Finding an outcrop open to the surface near an archaeological site, and then looking for evidence there that it was mined, can be an effective technique. Evidence could be tool marks, or excavation pits or campsites; but those might be difficult to identify if hundreds or thousands of years have passed since the quarry was used. Once a potential quarry has been identified, the archaeologist submits samples to a laboratory for sourcing, a process that breaks down the chemical or mineral content of a material, using Neutron Activation Analysis, or X-ray Fluorescence or another analytical tool. That provides a greater assurance that the proposed connection between tool and quarry is likely correct. However, quarries can vary in quality and content within a single deposit, and it may be that the chemical make up of the object and the quarry may never be perfectly matched. Some Recent Studies The following are some recent quarry studies, only a fraction of the available research which has been conducted. Wadi Dara (Egypt). This gold and copper mine was used during the Early Dynastic and Old Kingdom periods (3200–2160 BCE). Evidence includes pit trenches, tools (grooved stone axes and pounding slabs), smelting sites and slags from furnaces; as well as several huts where the miners lived. Described in Klemm and Klemm 2013. Carn Menyn (Preseli Hills, Wales, UK). The unique blend of rhyolites and dolerites at Carn Menyn mine were quarried for the 80 bluestones at Stonehenge, 136 miles (220 km) away. Evidence includes a scattering of broken or abandoned pillars of the same size and proportion as those at Stonehenge, and some hammer stones. The quarry was used before and after Stonehenge was built, between 5000–1000 BCE. See Darvill and Wainright 2014. Rano Raraku and Maunga Puna Pau Quarries (Rapa Nui aka Easter Island). Rano Raraku was the source of the volcanic tuff which was used to sculpt all 1,000 of the Easter Island statues (moai). The quarry faces are visible and several uncompleted statues are still connected to the bedrock. Described in Richards and others . Maunga Puna Pau was the source for the red scoria hats the moai wear, as well as other buildings used by the people of Rapa Nui between 1200–1650 CE. Described in Seager 2014. Rumiqolqa (Peru). Rumiqolqa was a quarry where Inca Enpire (1438–1532 CE) stonemasons excavated andesite for temples and other structures in the capital city of Cusco. Mning operations here entailed the creation of pits and cuts on the quarry landscape. Huge stone blocks were cut by using wedges placed in natural fractures, or by creating a line of holes then using wooden or bronze poles as pry bars, rock hammers and stone and bronze chisels. Some stones were further reduced in size before being dragged along the Inca road to their final destination. Inca temples were made of a variety of materials: granite, diorite, rhyolite, and andesite, and many of those quarries have been found and reported by Dennis Ogburn (2013). Pipestone National Monument (USA). This national monument in southwestern Minnesota was used as a source for catlinite, one of several mines scattered through the midwest that produce a sedimentary and metamorphic rock that was used by Native American communities to manufacture ornaments and pipes. Pipestone NM is known to have been an important religious and quarry site for historic period Native American groups during the 18th and 19th centuries CE. See Wisserman and colleagues (2012) and Emerson and colleagues (2013). Sources Bloxam, Elizabeth. Ancient Quarries in Mind: Pathways to a More Accessible Significance. World Archaeology 43.2 (2011): 149–66. Print.Darvill, Timothy, and Geoffrey Wainwright. Beyond Stonehenge: Carn Menyn Quarry and the Origin and Date of Bluestone Extraction in the Preseli Hills of South-West Wales. Antiquity 88.342:1099–14 (2014). Print.Emerson, Thomas, et al. The Allure of the Exotic: Reexamining the Use of Local and Distant Pipestone Quarries in Ohio Hopewell Pipe Caches. American Antiquity 78.1 (2013): 48–67. Print.Klemm, Rosemarie, and Dietrich Klemm. Gold Production Sites and Gold Mining in Ancient Egypt. Gold and Gold Mining in Ancient Egypt and Nubia. Natural Science in Archaeology: Springer Berlin Heidelberg, 2013. 51–339. Print.Kloppmann, W., et al. Tracing Medieval and Renaissance Alabaster Works of Art Back to Quarries: A Multi-Isotope (Sr, S, O) Approach. Archaeometry 56.2 (2014): 203–19. Print.Ogburn, Dennis E. Variation in Inca Bui lding Stone Quarry Operations in Peru and Ecuador. Mining and Quarrying in the Ancient Andes. Eds. Tripcevich, Nicholas and Kevin J. Vaughn. Interdisciplinary Contributions to Archaeology: Springer New York, 2013. 45–64. Print. Richards, Colin, et al. Road My Body Goes: Re-Creating Ancestors from Stone at the Great Moai Quarry of Rano Raraku, Rapa Nui (Easter Island). World Archaeology 43.2 (2011): 191–210. Print.Seager Thomas, Mike. Stone Use and Avoidance on Easter Island: Red Scoria from the Topknot Quarry at Puna Pau and Other Sources. Archaeology in Oceania 49.2 (2014): 95–109. Print.Summers, Geoffrey D., and Erol Ãâ€"zen. The Hittite Stone and Sculpture Quarry at Karakiz Kasabasi and Hapis Bogazi in the District of Sorgun, Yozgat, Central Anatolia. American Journal of Archaeology 116.3 (2012): 507–19. Print.Tripcevich, Nicholas, Jelmer W. Eerkens, and Tim R. Carpenter. Obsidian Hydration at High Elevation: Archaic Quarrying at the Chivay Source, Southern Peru. Journal of Archaeological Science 39.5 (2012): 1360–67. Print.Uchida, Etsuo, and Ichita Shimoda. Quarries and Transportation Routes of Angkor Monument Sandstone Blocks. Journal of Archaeological Science 40.2 (2013): 1158–64. Print.Wisseman, Sarah U., et al. Refining the Identification of Native American Pipestone Quarries in the Midcontinental United States. Journal of Archaeological Science 39.7 (2012): 2496–505. Print.

Amalgam Definition and Uses

Amalgam Definition and Uses An amalgam is a type of alloy found in dentistry, mining, mirrors and other applications. Here is a look at an amalgams composition, uses, and the risks associated with use. Key Takeaways: Amalgam Simply put, an amalgam is an alloy of the element mercury.While mercury is a liquid element, amalgams tend to harden.Amalgams are use to make dental fillings, to bind to precious metals so they can be isolated later, and to produce mirror coatings.As with elements in other alloys, a small amount of mercury may be released by contact with an amalgam. Because mercury is toxic, amalgams may present health or environmental risks. Amalgam Definition An amalgam the name given to any alloy of mercury. Mercury forms alloys with almost all other metals, except iron, tungsten, tantalum, and platinum. Amalgams may occur naturally (e.g., arquerite, a natural amalgam of mercury and silver) or may be synthesized. Key uses of amalgams are in dentistry, gold extraction, and chemistry. Amalgamation (the formation of an amalgam) is usually an exothermic process that results in hexagonal or other structural forms. Amalgam Types and Uses Because the word amalgam already indicates the presence of mercury, amalgams are generally named according to the other metals in the alloy. Examples of important amalgams include: Dental Amalgam Dental amalgam is the name given to any amalgam used in dentistry. Amalgam is used as a restorative material (i.e., for fillings) because its fairly easy to shape once mixed, but hardens into a tough substance. Its also inexpensive. Most dental amalgam consists of mercury with silver. Other metals that may be used with or in place of silver include indium, copper, tin, and zinc. Traditionally, amalgam was stronger and longer-lasting than composite resins, but modern resins are more durable than they used to be and strong enough for use on teeth subject to wear, such as molars. There are disadvantages to using dental amalgam. Some people are allergic to the mercury or other elements in amalgam. According to Colgate, the American Dental Association (ADA) reports fewer than 100 cases of amalgam allergy have been reported, so its very rare. A more significant risk is posed by the release of small amounts of mercury vapor as the amalgam wears over time. This is primarily a concern for persons already exposed to mercury in daily life. Its recommended pregnant women avoid getting amalgam fillings. The ADA does not recommend getting existing amalgam fillings removed (unless they are worn or the tooth is damaged) because the removal process can damage existing healthy tissue and may result in the unnecessary release of mercury. When an amalgam filling is removed, a dentist uses suction to minimize mercury exposure and takes steps to prevent mercury from entering the plumbing. Silver and Gold Amalgam Mercury is used to recover silver and gold from their ores because the precious metals readily amalgamate (form an amalgam). There are different methods of using mercury with gold or silver, depending on the situation. In general, the ore is exposed to mercury and the heavy amalgam is recovered and processed to separate the mercury from the other metal. The patio process was developed in 1557 in Mexico to process silver ores, although silver amalgam is also used in the Washoe process and in panning for the metal. To extract gold, a slurry of crushed ore can be mixed with mercury or run across mercury-coated copper plates. A process called retorting separates the metals. Amalgam is heated in a distillation retort. The high vapor pressure of mercury allows for easy separation and recovery for re-use. Amalgam extraction has largely been replaced by other methods because of environmental concerns. Amalgam slugs may be found downstream of old mining operations to the present day. Retorting also released mercury in the form of vapor. Other Amalgams In the mid-19th century, tin amalgam was used as a reflective mirror coating for surfaces. Zinc amalgam is used in the Clemmensen Reduction for organic synthesis and the Jones reductor for analytical chemistry. Sodium amalgam is used as a reducing agent in chemistry. Aluminum amalgam is used to reduce imines to amines. Thallium amalgam is used in low temperature thermometers because it has a lower freezing point than pure mercury. Although normally considered a combination of metals, other substances may be considered amalgams. For example, ammonium amalgam (H3N-Hg-H), discovered by Humphry Davy and Jons Jakob Berzelius, is a substance that decomposes when it comes into contact with water or alcohol or in air at room temperature. The decomposition reaction forms ammonia, hydrogen gas, and mercury. Detecting Amalgam Because mercury salts dissolve in water to form toxic ions and compounds, its important to be able to detect the element in the environment. An amalgam probe is a piece of copper foil to which a nitric acid salt solution has been applied. If the probe is dipped in water that contains mercury ions, a copper amalgam forms on the foil and discolors it. Silver also reacts with copper to form spots, but they are easily rinsed away, while amalgam remains.