Evaluation of corrosion rate AK80 and ZK60 Mg alloys Essay

Evaluation of corrosion rate AK80 and ZK60 Mg alloys - Essay Example (R.K. Sinnott, 2005) (2) Galvanic Corrosion- When two dissimilar metals are in contact in an atmosphere conducive to corrosion, then by its position in the electrochemical series one forms the anode and the other forms the cathode. The anode thus formed readily corrodes. This principle is used to protect the outside hull of ships by using sacrificial zinc anodes. By its position in the electrochemical series zinc forms the anode and undergoes material erosion thereby protecting the steel hull. (Oliver M. Siebert, B.et al; 1997) (3) Pitting- This is a highly localized form of corrosion. Usually materials are given a good surface finish to prevent its occurrence. The rate of corrosion in such cases is difficult to predict because once the corroding point breaks through the surface finish the material degradation progresses in a rapid manner. This proceeds by forming a pit and in an oxygenated atmosphere its activity is increased. Slag inclusion and entrapment of air during welding and formation of bubbles in pipes and valves during liquid flow all lead to pitting corrosion. (4) Inter-granular Corrosion-This is a form of corrosion which happens in alloying materials. Since alloys are a mix of different metals, the impurities tend to accumulate at the grain boundaries during heat treatment. This leads to propagation of corrosion although the amount of material corroded is small. (Oliver M. Siebert, B.et al; 1997) (5) Stress induced corrosion- This form of corrosion proceeds when materials are subjected to highly stressed environments. After a welding process, there will always be residual stresses that need to be relieved by post weld heat treatment. Failure to do so will lead to these stresses creating cracks and fissures in the welds. Materials that are subjected to repeated cyclic loads may fail due to fatigue stresses that are generated with time. Under such conditions the

Head Trauma Research Paper Example | Topics and Well Written Essays - 1750 words

Head Trauma - Research Paper Example . What then becomes the main question is to what extent the current NFL will attempt to ameliorate the risks that recent studies have indicated. As such, this brief research paper will consider the following three research areas as a means of drawing inference upon the main research question: 1) to what extent has mental health evaluations of current and former NFL players revealed with regards to the health consequences of frequent and prolonged head injuries, 2) to what extent has this level of long-term head injury been discussed and researched within the medical community, 3) what preventative measures, both in the way that the game is played, coached, and recruited can help to ameliorate this risk and are any of these approaches likely to take hold within the current environment that defines today’s NFL. It can be seen that for the most part the level of analysis that has been performed, regarding the long-term effects of head trauma, has made it fairly evident that there is a clear and identifiable link between head trauma and mental health issues and/or neurological disorders. ... It does not take a large body of research to realize that the game of football is filled with heavy impacts and oftentimes characterized by head trauma (Jarret 1). Still, the shareholders within the decision making branches of the process sought little action with regards to seeking to identify and possibly ameliorate the broad range of known mental health issues that were beginning to show themselves within current and past players. Instead, the issue was subsequently swept under the rub as it was determined that the bad press and negative image that this could present to the game as well as the marked reduction in overall profits were too costly. Yet, as it became increasingly clear from an array of highly publicized issues, the sports and medical communities could no longer ignore the role that head trauma played within the National Football League. As a function of this level of exposure, the medical community began to focus more and more specifically on the level to which mental health issues were a direct result of the injuries and trauma sustained on the field of play. As the level and body of overall knowledge continued to grow and advance, medical practitioners and sports science specialists alike came to be aware of the true nature in which mental health was irrevocably linked to the ways in which players were repeatedly injured on the field and projected these injuries long after their short careers had drawn to a close (Tamney 5). This information leads the analysis to a fundamental juncture of understanding. It appears, from the research that has thus far been conducted, that key shareholders within the institution of professional