...Solidification and crystalline imperfections: When molten alloys are cast, solidification starts at the walls of the mold as it is being cooled. The solidification of the alloy takes place not at a specific temperature but over a range of temperatures. While the alloy in the this range, it has a pasty form that consist of solid, tree-like structures called dendrites (meaning tree-like) and metal. The formation of Stable Nuclei in Liquid Metals: The two main mechanism by which the nucleation of solid particles in liquid metal occurs are homogeneous nucleation and heterogeneous nucleation. Homogeneous Nucleation in a liquid melt occurs when the metal itself provides the atoms needed to form nuclei. When a pre liquid metal is cooled below its equilibrium freezing temperature to a sufficient degree, many homogeneous nuclei are created by slow-moving atoms bonding together. For a nucleus to be stable so that it can grow into a crystal, it must reach a critical size. A cluster of atoms bonded together that is less than a critical size is called an embryo and one that is larger than the critical size is called a nucleus. Embryos: Small particles of a new phase formed by a phase (i. e. solidification) that are not of critical size and that can resolve. Nucle: Small particles of a new phase formed by a phase change (e . i . solidification) that can grow until the phase change is complete. Homogeneous Nucleation: The formation of small regions of a...
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...Principally, there is a marked increase in hardness and electrical resistivity with the amount of cold working. Microstructurally, this increment in internal energy is associated with an increase in the dislocation density as well as the density of point defects, such as vacancies and interstitials. For most metals, the dislocation density increases from the values of 106-107 lines/cm2 (typical of the annealed state) to 108-109 after a few percent deformation and up to 1011 -1012 lines/cm2 after heavy deformation. At a more macrostructural level, the grains become markedly elongated in the direction of working and heavily distorted. This distortion is evident from a bending of annealing twins and from unevenness in etching caused by local strain inhomogeneities. While the increased hardness and strength that result from the working operation can be important, it is often necessary to return the metal to its initial condition by annealing. This usually means holding the cold worked metal at a temperature above about 1/3 of the absolute melting point for a period of time. The annealing treatment is divided into three distinct regions: 1. Recovery: This usually occurs at low temperatures and involves motion and annihilation of point defects as well as annihilation and rearrangement of dislocations resulting in the formation of subgrains and subgrain boundaries (e.g., tilt and/or twist low-angle boundaries). A distinctive feature of the recovery process is that it...
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...Cold Working of Brass Kevin Louie MatE 25 October 20, 2014 | Marine Research Corporation | To: | Irene Huang | From: | Kevin Louie | Date: | September 29, 2014 | Re: | Determination on whether brass ingot can be used instead of plate form for a motor bracket application. | | | In response to the assigned investigation for Equipment used in the Oceanographic Research Platforms in the Arctic region, the following observation and test were performed. The scenario is having Research equipment installed on the Research Platforms that can survive harsh marine environments while operating for long periods of time with little or no maintenance. The material used for these equipment are to be made of brass plate because it is good corrosion resistance, easy machining tough. The question seeking for an answer of the investigation is “Can buying brass ingot and roll it flat to get a 60 percent reduction in thickness and hardness of 45 without it cracking?” For this experiment, there was two test that was conducted, Cold Working test and the Heat Treatment Test, on a sample of 260 Brass in ingot form. For the Cold Working Test, the first done was putting the sample through a Stanat Rolling Mill to reduce the thickness of the ingot. Part two of the Cold Working Test was to use the Rockwell Hardness Tester to measure the hardness of Brass. Do this test ten times at increments of -0.75 from 10.5mm to 3mm. At each targeted thickness, measure the width and length. The result...
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...Introduction The following is a basic report with regards to three specific questions which will be answered, centered on material studies. The first question is based around work hardening, the changes in the atomic structure as a result thereof and the reason why some materials are more susceptible to work hardening than others. The second question is based on the process of embrittlement, as well as listing a few different ways in which embrittlement can occur. The third and last question is based on the significance of heat affected zones, with special emphasis on the effects with regards to steel. Work hardening Work hardening is a phenomenon found in metallic materials, where deformations in the metals have led to the metal itself becoming strengthened, or harder as such. The deformations which cause this effect are called plastic deformations, which means that the metal material was stressed beyond the point where elastic deformation takes place, thereby resulting in a permanent deformation in the crystalline structure of the metal material. These plastic deformations are caused by high heat exposure for a specific minimum length of time, causing the molecules within the crystalline structure to rearrange themselves. A few common physical processes which take place on metals and can cause this effect are as follows: hammering, bending, rolling, drawing, shearing, squeezing or collisions between metals for example. All of the above would result in some form of work...
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...15% Specimen 4 Thickness= 1.4+0.006=1.406mm Indentation Hardness test Indentation Force=20N Specimen 1: I. 154HV II. 157HV III. 157HV Average Hardness= 157 HV Specimen 2: I. 162HV II. 160HV III. 159HV Average Hardness= 160.33 HV Specimen 1: I. 169HV II. 174HV III. 174HV Average Hardness= 172.33 HV Specimen 1: I. 184HV II. 183HV III. 181HV Average Hardness= 182.66 HV Conclusion: We observed that- * As we deform the material hardness increases. * Metals harden due to deformation at room temperature (cold working). * Grain boundaries, impurities, precipitates act as barriers or obstacles to the movement of dislocations. Dislocations get piled up at the grain boundaries. * To overcome the barriers and cause...
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...Waking up not knowing where I was or what was going on. Only to see my mother and father in tears along with my sisters, I will never forget the look on each one of their faces till the day I die and long after. Sheer disappointment and fear is all I could see in their eyes. As I slowly started to regain my consciousness I began to realize what was going on. I was in a hospital bed, IV syringes and defibrillator patches all over my body. I was in the 10th grade, I was on top of the world. Perfect set up; friends, cars, family, loved everywhere and loved everyone around me. However I was extremely ungrateful, took everything for granted and at the time I did not realize how blessed I was. Was taking everything for granted. I felt like the rules did not apply to me. I had everything a kid at my age could ask for. Being the only boy sibling of four other sisters I was spoiled rotten. The answer ‘no’ was never on the table for me. Little did I know my life was about to take a turn for the worst but also turned out to be one of the best learning experiences as well. It all started one random night my cousins, friends and I met up as usual at my house for a little get-together. We got a case of beer and started drinking with no plans of heading down town. We figured we would stay in our compound have a couple beers, a few laughs and call it a night. Little did we know that what was to come would never be forgotten or be changed. One beer after the other things started to escalate...
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...Running Title: Acute posterior sternoclavicular fracture-dislocation in a 10-year-old boy Authors: Joseph Y. Choi, MD, PhD, Devin P. McFadden, MD, Vipul N. Nanavati, MD Corresponding Author: Francis G. O’Connor, MD Introduction A 10-year-old male was referred to the office after falling onto his left shoulder while playing football. At presentation, he denied any numbness, tingling or loss of sensation of his left upper extremity. Examination of his shoulder girdles revealed an internally rotated left shoulder and shortened clavicular distance. He did have a visible deformation of his left clavicle when compared to the contralateral, uninjured side and had excruciating pain to palpation of the clavicular and sternoclavicular area. The patient had full flexion and extension at the elbow. Shoulder deltoid was intact as were internal and external rotation of his shoulder. Furthermore, the patient denied being short of breath, feeling dizzy, or with difficulty swallowing. Radiographs of the left clavicle and sternoclavicular joint (SCJ) at the initial visit were remarkable for a posterior dislocation of the clavicle. A magnetic resonance imaging (MRI) study of the left clavicle and SCJ revealed that it was posteriorly displaced and edema was present at the fracture site. The physeal attachment to the manubrium was intact. Furthermore, the anterior portion of the clavicle was abutting the brachiocephalic and left subclavian vein (Figure 1). ...
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...I remember laying in a bed at the hospital while all these doctors came in at various times to do things with me. That’s what you get when you need surgery. I was in there to have my shoulder repaired. The tragic accidents continuously replay in my mind while I mindlessly lay in the bed. Surgery is unforgettable, terrifying, and painful.. Everyone probably remembers playing badminton in high school gym class. It was more to me than just another class activity. It was a game that changed my life. One day we were playing it and I went up to hit the birdie and “pop”. I suddenly drop to the ground. The pain from my shoulder dislocating was unbearable. I finally stand up and somehow I am capable of getting my shoulder back in. But I was unable to move it without screaming out in pain. The teachers help me ice it but that doesn’t help me as much as it should. Eventually my mom gets called to come pick me up and she takes me right to the hospital. Which is when the long journey began. The visit to the hospital declared nothing. We were scheduled to meet with a specialist that later ordered a MRI for me. Which then told us that my capsule was too loose and needed to have surgery to tighten it up. If I didn’t have surgery then I would continue to dislocate my shoulder. Therefore we did choose to have it done for me. Weeks later I show up to the hospital at 6:45 am. The nurses help get me changed and the iv in my arm. I can’t even remember how many different doctors came...
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...Diasporic Cross-Currents in Michael Ondaatje’s Anil’s Ghost and Anita Rau Badami’s The Hero’s Walk HEIKE HÄRTING N HIS REVIEW of Anil’s Ghost, Todd Hoffmann describes Michael Ondaatje’s novel as a “mystery of identity” (449). Similarly, Aritha van Herk identifies “fear, unpredictability, secrecy, [and] loss” (44) as the central features of the novel and its female protagonist. Anil’s Ghost, van Herk argues, presents its readers with a “motiveless world” of terror in which “no identity is reliable, no theory waterproof” (45). Ondaatje’s novel tells the story of Anil Tessera, a Sri Lankan expatriate and forensic anthropologist working for a UN-affiliated human rights organization. Haunted by a strong sense of personal and cultural dislocation, Anil takes up an assignment in Sri Lanka, where she teams up with a local archeologist, Sarath Diyasena, to uncover evidence of the Sri Lankan government’s violations of human rights during the country’s period of acute civil war. Yet, by the end of the novel, Anil has lost the evidence that could have indicted the government and is forced to leave the country, carrying with her a feeling of guilt for her unwitting complicity in Sarath’s death. On one hand, Anil certainly embodies an ethical (albeit rather schematic) critique of the failure of global justice. On the other, her character stages diaspora, in Vijay Mishra terms, as the “normative” and “ exemplary … condition of late modernity” (“Diasporic” 441) — a condition usually associated...
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...In Nauja Kleist’s article, "Elusive Jannah: The Somali Diaspora and a Borderless Muslim Identity by Cawo M. Abdi," she expounds on the Somali idea of an earthly paradise, called jannah. Although, the place in which jannah has been referred to has changed throughout time the idea of a “paradise” existing in America is like the idea of “the American dream”. A place of belonging and prosperity that will allow for a thriving family. Even though Somalis may see the United States as a place of jannah, they may face a low socioeconomic position, challenged gender and family relations, and a sense of dislocation and religious alienation (Kleist 647). After a rise in discrimination after the events of 9/11 many Somalis have shifted their view of what...
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...Multicultural Assessment Norma Garcia Grand Canyon University Family Centered Health Promotion NRS-429V Serina Madden February 25, 2015 Multicultural Assessment The author of this paper is a student at Grand Canyon University who is currently taking Family Centered Health Promotion. The topic discussed in class this week was, Culture and Cultural Competency in Health Promotion. The corresponding assignment to this course was to perform a heritage assessment; three families of the community were interviewed. The Heritage Assessment tool consist of 29 questions about families background, religious and ethnicity practices and current living status. The Interviews where performed via telephone calls. Veronica Navarro is a Hispanic female who migrated to the United States of America (USA) at the age of 12. Her parents and grandparents are Mexicans. She grew up with her six siblings and extended family living with her as a child. She was raised as Catholic and as an adult became a Christian. Veronica is married to a Hispanic male; they practice Christianity at home by praying, and celebrating religious holidays. They also participate in ethnic activities such as dancing, singing, Holiday celebrations and festivals. Veronica and her family currently live in a multicultural neighborhood. Veronicas native language is Spanish; she speaks both English and Spanish equally (V. Navarro, personal communication, February 20, 2015). Sarah Redmond is a single White female raised and...
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...8 Creolization in Anthropological Theory and in Mauritius Thomas Hylland Eriksen A great amount of intellectual energy has been invested in cultural mixing during the last decades. Reacting against an idea of boundedness, internal homogeneity, and stability that has been associated with mainstream twentieth-century anthropology, hundreds—possibly thousands—of anthropologists have tried to redefine, reform, revolutionize, or even relinquish that abhorred “C” word—”culture.” The range of engagement is suggested in the apparent congruence between postmodernist American anthropologists (for example, Clifford & Marcus 1986) and their now classic critique of the Geertzian notion of cultural integration, and the older European critique of the structural-functionalist idea of social integration, which was led by people such as Barth (1966), whose rationalism and naturalism is everything but postmodernist. In both cases, presuppositions of integrated wholes, cultures or social structures, have been debunked. From being a discipline concentrating its efforts on understanding nonliterate societies, often implicitly positing the uncontaminated aborigine as its hero, anthropology increasingly studies cultural impurity and hybridity, and the dominant normative discourse in the field has shifted from defending the cultural rights of small peoples to combating essentialism and reifying identity politics. While this development has been important and necessary for a variety of reasons,...
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...GIS 3117 Modern China Spring, 2014 Dr. Amy Y. Situ-Liu (Please use Blackboard internal email for your communication with the instructor. In case of an emergency that prevents you from accessing to your computer, please leave your voice mail at 652-4314, and then email me afterward) Orientation: Location: Textbooks (required): China Since 1949 By Linda Benson, Longman, 2nd edition, 2011 China: The Balance Sheet – What the World Needs to Know About the Emerging Superpower By Fred Burgsten and others, 2006 China Road By Rob Gifford, Random House, 2008 Video Programs: All assigned programs are available on “Video on Demand” provided in our library homepage. Most of them are ready for you to review. But since they are online programs, a few may be not available by the times you click the links. If so, just skip that one and watch the others. Please try both “by segment” or “by title” for your search. Course Description: China, the most populous country, is an excellent "laboratory" for the social scientific study of political, economic and social behavior. The Twentieth Century alone has seen many changes in China's fundamental institutions: from imperial courts to military regimes and single-party police states, from rural households to international stock-holding companies, and from foot-binding and slavery to mass movements and democracy protests. The latest development in the last decade has led to the calling...
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...Diversity in the Workplace Alain Kraussman Hall Baker College Online Human Behavior Management of Organization/BUS615 December 6, 2012 Introduction Diversity is defined as “the condition of having or being composed of differing elements: variety; especially: the inclusion of different types of people (as people of different races or cultures) in a group or organization” ("diversity," 2012). These differing elements are becoming more and more prevalent in today’s society, and especially in the business world. Emigrants from every country in the world have made their way to the shores of America, and from there, to millions of companies and organizations across the nation. From the owner of the neighborhood corner store to the CEO position at Citigroup and Pfizer, foreign-born employees are giving this country a new, diverse, face. Diversity is not just of race, but of age, gender, ethnicity, religion, and disability. In every decade since 1900, the percentage of women 16 years and older in the workplace has increased, going from just 18.3 percent in 1900 to 53.6 percent in 2010 ("Women in the," 2007). The same holds true of disabled workers. In December 1976, there were roughly 2,088,242 blind and disabled workers in the United States. Growing nearly every year since, the Social Security Administration reports that as of December 2011, there are 6,996,435 blind and disabled people in the workforce ("Ssi annual statistical...
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...Participant observation is defined as first hand experience. Participant observation is a method developed by Anthropologists in the early 20th century. When Anthropologists noticed that in order to fully understand the question, “Why” in culture. Why do a certain people do this, why is that important, or why do they all do it, are just some of the questions anthropologists use participant observation. The key to participant observation is fieldwork, where the anthropologist actively lives with the people of the culture they are studying for about a year or more. Where the anthropologist goes through culture shock by leaving all their possessions at home and starting a new. This technique of studying gets the anthropologist to become one with the culture, where they participate in ceremony’s and traditions with the people as a member. So much so that they go through culture shock once they return home, because they have opened their minds to a whole new way of thinking and living. Colin M. Turnbull is an anthropologist who went to live in the Ituri Forest with a group of people called the Pygmies. The Pygmies is a culture that many people before Turnbull mistaken as uneducated and weren’t living life to the fullest because of this. Turnbull had two voyages to the Forest where in his first voyage he saw the Nkumbi ritual and was inducted as a member of the Pygmies. Two years later he went back to the forest leaving everything behind, unlike his first voyage where he believed he...
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