The pros of mandatory service

Introduction Students appear to be overwhelmed by the myriad of activities that make up their school programs. Many would argue that this would be just another burden for them. However, choosing such a stance would obscure the long term merits of the program. Focusing on the short discomforts of mandatory voluntary service causes one to miss out on the great benefits that can emanate from the program. Not only would participants gain work-related skills like team-building and time management, they would also develop a deep community identity.Advertising We will write a custom research paper sample on The pros of mandatory service specifically for you for only $16.05 $11/page Learn More Why the bill should become law Mandatory community or military service would strengthen students’ association with their communities. As students volunteer in hospitals, fire departments, drug recovery centers and others, they will get to learn about unmet needs in their community (Worrall 15). This could compel them to become passionate about filling those gaps and thus more active in their adult life. For instance, a training psychologist could learn about the lack of adequate follow-through in drug rehabilitation centers and this could propel him or her to become a better professional in the future. Alternatively, if a person finds that things are working well in his or her community, the volunteer could develop a sense of pride. He or she will appreciate the valuable work that other people are putting into his or her area of residence. Therefore, the program will enhance community identity and ownership over initiatives. One may also argue that modern American youth are too consumer-oriented (Longo 93). Most of them tend to focus on their individual needs rather than that of their surroundings. These young men and women only care about what they can get out of their parents or the government rather than what they can give back. National vo luntary services would enable such persons to connect with forces beyond themselves and develop a moral outlook (Sauerwein 15). Mandatory volunteer work will strengthen students’ prospects for employment. Individuals who work in community services must build rapport with others. They need to know teamwork as they must consult with paid professionals, fellow volunteers, or beneficiaries of the programs (Light 81). Additionally, these persons must plan their time adequately in order to fit it into their school routine. They will thus learn time management skills. Several students are already doing volunteer work and they do not even know it. One indication of this trend is participation in internship programs. Internship often gives students an added advantage in job recruitments (Shivaun 43). Consequently, the same may be said of the proposed mandatory community program. Opportunities and skills obtained from the plan would be priceless. For instance, individuals would build n etworks in their desired career line, and this could enhance their prospects for finding employment.Advertising Looking for research paper on education? Let's see if we can help you! Get your first paper with 15% OFF Learn More Conclusion Students require opportunities to make them more marketable to employers, and voluntary service is one such avenue. The consumerist attitude that pervades western societies has caused American youth to become self-centered. This policy could foster a greater moral attitude among the country’s citizenry. In essence, such a policy would make participants better professionals because they would learn about inadequacies in current arrangements. This could cause them to foster change in their professions. Some short term sacrifices always have to be made in order to realize a greater good. Students, parents, employers and other stakeholders will appreciate the proposed law once they see the gains of the policy. Works Cited Light, Ri chard. Making the most of college: Students speak their minds. Harvard: HUP, 2001. Print. Longo, Nicholas. Why community matters: Connecting education with civic life. NY: SUNY press, 2007. Print. Sauerwein, Kristina. â€Å"A compelling case for volunteers.† The American School Board Journal 183.3 (1996): 29-31. Print. Shivaun, Perez. Assessing service learning using pragmatic principles of Education. Texas: Texas State University Press, 2000. Print. Worrall, Laurie. â€Å"Asking the community: A case study of community partner perspectives.† Michigan Journal of Community Service Learning 14.1(2007): 5-17. Print.Advertising We will write a custom research paper sample on The pros of mandatory service specifically for you for only $16.05 $11/page Learn More This research paper on The pros of mandatory service was written and submitted by user S0l0 to help you with your own studies. You are free to use it for research and reference purposes in order to write your own paper; however, you must cite it accordingly. You can donate your paper here.

Analysis of teen magazines.

Analysis of teen magazines. The main theme the cover of the widely known magazine, Cosmopolitan, is trying to convey is sex. There are three captions that are bold and stand out with bright yellow writing. Each caption has the word sex in it and that is the main idea this magazine is getting through to these young women or teenagers. Cameron Diaz, a pretty and famous actress is on the cover of the magazine. She is in a sexy pose with a low cut spaghetti strap tank top in order to catch guys' attentions who are passing by the magazine stand and to attract the girls who would do anything to be or be like her.There are 54 different featured columns or stories. Of the 54, 48 of them have to do with beauty, sex, celebrities, and/or fashion. There are a few stories that are meaningful; however 95% of the magazine is all about superficialities.James G. Howes and Welsh actress Catherine Zeta Jo...A few examples of some titles are 101 sex tips, His sexiest time, Fall's Perfect Pants, Beauty news, Tackling touchy subject s in bed, Women who seduce teens, Bedroom blog, and so on. As one can tell by just the titles, this magazine revolves around very superficial ideas and con women into thinking that it is a necessity to be up to date with all the celebrity drama and new fashion styles. The theme that stands out to me the most is how to improve the girl's sex life. I understand now, why girls are so pressured and eager to start having sex at such a young age. It is all around them flashing at them everywhere they go and they will obviously get curious and want to experience the "big hype" for themselves.There are ads every couple of pages and 77 out of the 90 ads...

Case study Example | Topics and Well Written Essays - 500 words - 65

Case Study Example It has been very aggressive in its profit responsibility; using its programs and projects as means of communication to showcase its products and services to a larger population. This has demonstrated to be even more effective than the traditional way of holding advertising campaigns. The overall mission of Toyota is to contribute to the society and the economy by producing high-quality products and services. This is achieved through the Toyota way, which is a philosophy, built on five principles: challenging long-term visions and approaching them with creativity, Kaizen i.e. continuously improve business processes. Genchi Genbustu which, means going to the source to verify the facts in order to make accurate decisions; stimulating teamwork and performance and finally respect for the others and the environment by responsibility for it. Thus, Toyotas concept of sustainable mobility is key to achieving the Toyota way, which believes in respecting the atmosphere, and taking care of it. The Toyota National Parks project has been very successful. Parks included in this partnership are Yellowstone National Park, Great Smoky Mountains National Park, Everglades National park, the Golden Gate Bridge Foundation, Yosemite National park, the Grand Canyon and the Santa Monica National Recreational reserves. The program tries to engage with the visitors at the park personally and expose them to Toyota’s hybrid vehicles which when used in a natural setting are able to receive messages about sustainable mobility. A corporate image study which was recently conducted shows that Toyota ranked highest among its competitors namely Toyota, Honda, Ford and GM when it came to indicators such as ‘Leader in High MPG’, ‘Leader in Technology Development’, ‘Environmentally Friendly Vehicles’ and in the ‘Wins Environmental Awards’ (107). I would suggest that Toyota gets involved in even more activities that raise environmental-friendly awareness. They should be proactive

Health Promotion Package for Diabetes Essay Example | Topics and Well Written Essays - 2000 words

Health Promotion Package for Diabetes - Essay Example Health promotion can take varied forms, depending on the concerned groups or individuals. Different constructs of health and well-being exist. In the context of Edna, various constructs are applicable in enhancing her well-being and health status. The constructs are multi-perspective and addresses various health concerns highlighted in the case study. Most relevant constructs includes; Social model theory of health promotion remains addressed from different perspective. It does not focus on medical profession domain alone. The social model does not entirely rely on the medical model on addressing various health issues. A multi-perspective approach that includes all the individual experiences and defined places are taken into consideration in this approach. Principally, there is a correlation dynamic interaction between the social structures and the concerned human agency. In addressing the medical conditions of Edna, a multi-perspective social model can find use in efficiently remedying her health concerns. Psychological model differs from medical model from the test that confirms and qualify an individual as sick. While the medical model may require an independent test to determine a medical condition, psychological model relies mostly on the psychological examinations that do not involve medical tests. For the case of Edna, psychological therapy may help relieve conditions such as stress due to death of the husband. Psychological model relies more on the subjective manifestation of the condition rather than the objective determinants of a given condition. Medical model of disease management utilizes the scientific theories and doctor patient relationship in managing a disease condition. Independent objective test are carried to determine specific condition affecting an individual. The medical models rely on the use of medicine in the management of health. For the case of Edna, medical

Pamantasan ng Lungsod ng Marikina Essay Example for Free

Pamantasan ng Lungsod ng Marikina Essay There are lots of effects which DotA brings to our society, to be particular, the youth. With no doubt this game is one of the hottest game in the market. In every Cyber Cafe you can see gamers stick with their screen and mouse and  keyboard, with their face that full of concentration and excitements finding ways to defeat their opposing team or enemies. Actually Computer games or DotA serves as a platform for youth to communicate. Teenagers who initislly don’t know each other can easily become friends through Computer games or playing DotA. Chapter I Introduction DotA effects have been continue for several years since the launch of the War of War Craft and the Frozen Throne. Almost every people especially the youth has played this game at the very beginning of the years. What is the content that DotA offers to the gamers? And how’s the excitements that brings towards the gamers. And you may ask a key question, how long will DotA effects last? The lifestyle of the youth who have been playing Computer Games especially DotA is affected by the game. There are both advantage and disadvantages for them. Let’s talkl about the advantages first. As one of the most playable games online, DotA can make the players become alert in the mental, They will also turn to be strategic and cooperative through computing the magic, damages, gold, physical reduction, present and other stuff, they will get more lore in mathematics. Thus the youth can also get some benefits on playing Computer games. Statement of the problem or Thesis Statement Why is Computer games or DotA so Addicting to Students? 1. A Time killer Boredom is the most common problem of most people today. DotA can consume a lot of time without you even noticing it . you just say after the game â€Å"WTF !, Im late !† 2. Non-exhasuting game Unlike basketball or other physical sports , you can play DotA until you can still mangae to sit, look at the monitor, use mouse and keyboard and think, Yes , using your is aslo tiring but it’ll takes an average of 3 games before you’d want to take a rest 3. Fame Source Most players want to be the best in this game to gain fame which I find natural but technically nonsense. I have to admit that thirst for fame drove me to practice and improve my game. After getting the fame I wanted, I asked myself â€Å"Now what?†. For players who don’t have plan on having DotA as their profession ,Fame isn’t that important. 4. Team work game When we were kids, we already love having team battles. That’s why a lot of team sports games cames up and multi-player computer games have been invented. Playing with teammates is more addicting than playing alone. 5. Tranquilizing DotA makes you forget your problems and make you think of simpler problems (like how to win the game) 6. Non violent war We love wars. That’s why there are shows like Wrestling, UFC ,Action films , etc. DotA is a chance to engage in wars safely. We can fight all day long and just stand up from our computer without even having a scratch on our face. 7. Easy to play Surveys shows that DotA is played by more people thatn other strategy like Starcraft. One of the reason is its simplicity. You only have to control one hero (great news for people who are not into doing micros.) 8. No height or physical disadvantages In basketball you cannot have a team composed of 5 short players. In Rugby , you should be muscular. In DotA you can be as thin and as short as you want and still own everyone. 9. Losing makes you thirsty to win On the other hand, losing is still addicting because you become more urge to have that wonderful feeling of winning. 10. Winning feels Good Yup, winning in every game makes you feel good and addicting. Background of the Study Significance of the study How to overcome DotA Addiction ? 1. Accept responsibility The problem lies within the individual, not within DotA. No attempt at beating addiction can succeed until the individual accepts its existence. 2. Identify the Impact How many hours a day do you spend playing DotA? Do you normally go out on the weekend?When was the last time you read a book?Identifying the negative impacts of the addiction will help you focus on positive improvements and getting back the things that you really are missing. 3. Avoid Blame Blaming others for problems that you alone must face does not solve the problems. 4. Set limits If you decide that you have 1 hour per day to spend playing DotA. Since DotA requires many hours of gameplay to have fun, you likely should consider a different game or different genre of games. 5. Stay positive Be positive whenever possible. While negative reinforcement is sometimes necessary, positive reinforcements will always go further in the end. What is DotA ? DotA is basically game expanded from version of War of War Craft, which initially a strategic game similar to Red Alert Series. But eventually evolved into current state. Gamers can play Dota in a Wide range ; from single player, local LAN, or LAN over internet connection with various country’s gamers. There contain variety of Heroes to be chosen as your character, There are many type of gaming modes , and different type of map for the game modes. There are lots of gamers who are more expert in the world of playing DotA . Chapter V Summary and Conclusion Summary and Conclusion We know that Playing computer games especially DotA brings bad effects to the students, they influenceed by the other gamers like â€Å"trash talks† they know how to gamble because they are playing DotA for â€Å"pustahan†. DotA really affects the lifestyle of the youth who are into this game, although it has one good benefit, but it corrupts the mind and the way the youth think. It also weakened the body system, money and moral values were not given importance because of this game.

Model for Predicting Fatigue Life of Nanomaterials

Model for Predicting Fatigue Life of Nanomaterials Introduction In the past, the primary function of micro-systems packaging was to provide input/output (I/O) connections to and from integrated circuits (ICs) and to provide interconnection between the components on the system board level while physically supporting the electronic device and protecting the assembly from the environment. In order to increase the functionality and the miniaturization of the current electronic devices, these IC devices have not only incorporated more transistors but have also included more active and passive components on an individual chip. This has resulted in the emerging trend of a new convergent system[1] Currently, there are three main approaches to achieving these convergent systems, namely the system-on-chip (SOC), system-in-package (SIP) and system on package (SOP). SOC seeks to integrate numerous system functions on one silicon chip. However, this approach has numerous fundamental and economical limitations which include high fabrication costs and integration limits on wireless communications, which due to inherent losses of silicon and size restriction. SIP is a 3-D packaging approach, where vertical stacking of multi-chip modules is employed. Since all of the ICs in the stack are still limited to CMOS IC processing, the fundamental integration limitation of the SOC still remains. SOP on the other hand, seeks to achieve a highly integrated microminiaturized system on the package using silicon for transistor integration and package for RF, digital and optical integration[1] IC packaging is one of the key enabling technologies for microprocessor performance. As performance increases, technical challenges increase in the areas of power delivery, heat removal, I/O density and thermo-mechanical reliability. These are the most difficult challenges for improving performance and increasing integration, along with decreasing manufacturing cost. Chip-to-package interconnections in microsystems packages serve as electrical interconnections but often fail by mechanisms such as fatigue and creep. Furthermore, driven by the need for increase the system functionality and decrease the feature size, the International Technology Roadmap for Semi-conductors (ITRS) has predicted that integrated chip (IC) packages will have interconnections with I/O pitch of 90 nm by the year 2018 [2]. Lead-based solder materials have been used for interconnections in flip chip technology and the surface mount technology for many decades. The traditional lead-based and lead-free solder bumps will not satisfy the thermal mechanical requirement of these fine pitches interconnects. These electronic packages, even under normal operating conditions, can reach a temperature as high as 150C. Due to differences in the coefficient of thermal expansion of the materials in an IC package, the packages will experience significant thermal strains due to the mismatch, which in turn will cause lead and lead-free solder interconnections to fail prematurely. Aggarwal et al [3] had modeled the stress experienced by chip to package interconnect. In his work, he developed interconnects with a height of 15 to 50 micrometre on different substrate using classic beam theory. Figure 1 shows the schematic of his model and a summary of some of his results. Although compliant intrerconect could reduces the stress experienced by the interconnect, it is still in sufficient. Chng et al. [4] performed a parametric study on the fatigue life of a solder column for a pitch of 100micrometre using a macro-micro approach. In her work, she developed models of a solder column/bump with a pad size of 50micrometre and heights of 50 micrometre to 200 micrometre. Table I shows a summary of some of her results. Table 1.1: Fatigue life estimation of solder column chip thickness (micrometre) 250 640 640 640 board CTE (ppm/K) 18 18 10 5 solder column height (micrometre) Fatigue life estimation/cycle) 50 81 N.A 171 3237 100 150 27 276 3124 150 134 31 518 4405 200 74 38 273 5772 It can be seen from Table 1.1 that the fatigue lives of all solder columns are extremely short. Apart from the 5ppm/K board where there is excellent CTE matching, the largest fatigue life of the solder column is only about 518 cycles. As expected, the fatigue life increases significantly when the board CTE decreases from 18ppm/K to 10ppm/K and as the height increases from 50micrometre to 200micrometre.This is mainly due to the large strain induced by the thermal mismatch as shown in Figure 1.2. The maximum inelastic principal strain was about 0.16 which exceeds the maximum strain that the material can support. Although the fatigue life of the chip to package interconnection can be increases by increasing the interconnects height, it will not be able to meet the high frequency electrical requirements of the future IC where they need to be operating at a high frequencies of 10-20 GHz and a signal bandwidth of 20 Gbps, By definition, nanocrystalline materials are materials that have grain size less than 100nm and these materials are not new since nanocrystalline materials have been observed in several naturally-occurring specimens including seashells, bone, and tooth enamel [5, 6]. However, the nanocrystalline materials have been attracting a lot of research interest due to its superior mechanical and electrical properties as compared to the coarse-grained counterpart. For example, the nano-crystalline copper has about 6 times the strength of bulk copper [7]. Furthermore, the improvement in the mechanical properties due to the reduction in grain size has been well-documented. Increase in strength due to the reduction in grain-size is predicted by the Hall-Petch relationship which has also been confirmed numerically by Swygenhoven et al [8] and was first demonstrated experimentally by Weertman [9]. The implantation of nanocrystalline copper as interconnect materials seems to be feasible from the processing viewpoint too. Copper has been used as interconnects materials since 1989 whereas nano-copper has also been widely processed using electroplating and other severe plastic deformation techniques in the past few years. For instance, Lu et al. [10] have reported electroplating of nano-copper with grain size less than 100 nm and electrical conductivity comparable to microcrystalline copper. Furthermore, Aggarwal et al [11] have demonstrated the feasibility of using electrolytic plating processes to deposit nanocrystalline nickel as a back-end wafer compatible process. However, there are certain challenges regarding implantation of nanocrystalline copper as interconnects materials. As discussed above, nanocrystalline copper have a high potential of being used as the next generation interconnect for electronic packaging. However, it is vital to understand their material properties, deformation mechanisms and microstructures stability. Although the increase in strength due to the Hall-Petch relationship which has also been confirmed numerically and experimentally by Weertman [9], the improvement in the fatigue properties is not well documented and no model has been established to predict/characterize these nano materials in interconnection application; conflicting results regarding the fatigue properties have also been reported. Kumar et al [12] reported that for nano-crystalline and ultra-fine crystalline Ni, although there is an increase in tensile stress range and the endurance limit, the crack growth rate also increases. However, Bansal et al. [7] reported that with decreasing grain size, the tensile stress range increases but the crack growth rate decreases substantially at the same cyclic stress intensity range. Thus, nanostructured materials can potentially provide a solution for the reliability of low pitch interconnections. However, the fatigue resistance of nanostructured interconnections needs to be further investigated. Since grain boundaries in polycrystalline material increases the total energy of the system as compare to perfect single crystal, it will resulted in a driving force to reduce the overall grain boundary area by increasing the average grain size. In the case of nanocrystalline materials which have a high volume fraction of grain boundaries, there is a huge driving force for grain to growth and this presented a presents a significant obstacle to the processing and use of nanocrystalline copper for interconnect applications. Millet et al [13] have shown, though a series of systematic molecular dynamics simulations, grain growth in bulk nanocrystalline copper during annealing at constant temperature of 800K can be impeded with dopants segregated in the grain boundaries regions. However, it has been observed that stress can trigger grain growth in nanocrystalline materials [14] and there is no literature available on impeding stress assisted grain growth. There is an impending need to investigate the impediment to grain growth caused by the dopant during fatigue/stress assisted grain growth Dissertation Objectives The goal of present project is to develop a model for the fatigue resistance of nano-materials that have been shown to have superior fatigue resistance. Accordingly, the following research objectives are proposed. Develops a model for predicting fatigue life of nanostructured chip-to-package copper interconnections Develops a fundamental understanding on the fatigue behavior of nanocrystalline copper for interconnect application Addresses the issue on the stability of nanocrystalline materials undergoing cyclic loading Overview of the Thesis The thesis is organized so that past research on nanocrystalline materials forms the basis of the understanding and new knowledge discovered in this research. Chapter 2 reviews much of the pertinent literature regarding nanocrystalline materials, including synthesis, deformation mechanisms, and grain growth. Chapter 3 describes a detailed overview of the technical aspects of the molecular dynamics simulation method including inter-atomic potentials, time integration algorithms, the NVT NPT, and NEPT ensembles, as well as periodic boundary conditions and neighbor lists. Include in this chapter is the algorithms for creating nanocrystalline materials used in this dissertations.. Chapter 4 describes the simulation procedure designed to investigate and develop the long crack growth analysis. The results of the long crack growth analysis will be presented at the end of Chapter 4. Chapter 5 presents the result and discussion on mechanical behavior of single and nanocrystalline copper subjected to monotonic and cyclic loading whereas Chapter 6 presents the result and discussion on the impediment to grain growth caused by the dopant during fatigue/stress assisted grain growth. Finally, conclusions and recommendations for future work are presented in Chapter 5. Chapter 2 This chapter offers an expanded summary of the literature published with regards to the fabrication methods, characterization, and properties of nanocrystalline materials in addition to a description of existing interconnect technology. 2.1 Off-Chip Interconnect Technologies Chip-to-package interconnections in microsystems packages serve as electrical interconnections but they will often failed by mechanisms such as fatigue and creep. Furthermore, driven by the need for increase the system functionality and decrease the feature size, the International Technology Roadmap for Semi-conductors (ITRS) has predicted that interconnections of integrated chip (IC) packages will have a I/O pitch of 90 nm by the year 2018 [2]. The International Technology Roadmap for Semiconductors (ITRS) roadmap is a roadmap that semiconductor industry closely follows closely and its projects the need for several technology generations. The package must be capable of meeting these projections in order for it to be successful. This section reviews some of the current interconnect technology. Wire bonding [15] as shown in Figure 2.1, is generally considered as one of the most simple, cost-effective and flexible interconnect technology. The devices on the silicon die are (gold or aluminum) wire bonded to electrically connect from the chip to the wire bond pads on the periphery. However, the disadvantages of wire bonding are the slow rate, large pitch and long interconnect length and hence this will not be suitable for high I/O application. Instead of wires in the wire bonding, tape automated bonding (TAB) is an interconnect technology using a prefabricated perforated polyimide film, with copper leads between chip and substrate. The advantage of this technology is the high throughput and the high lead count. However, it is limited by the high initial costs for tooling. An alternative to peripheral interconnect technology is the area-array solution, as shown in Figure 2.3, that access the unused area by using the area under the chip. In area-array packaging, the chip has an array of solder bumps that are joined to a substrate. Under-fill is then fills the gap between the chip and substrate to enhance mechanical adhesion. This technology gives the highest packaging density methods and best electrical characteristics of all the avaiable interconnection technology. However, not only is its initial cost is high, it requires a very demanding technology to establish and operate. With the need for higher I/O density, compliant interconnects have been developed to satisfy the mechanical requirements of high performance micron sized interconnects. The basic idea is to reduce shear stress experienced by the interconnects through increasing their height or decreasing of its shear modulus (i.e. increases in their compliant) and hence the name compliant interconnects. Some of recent research in compliant interconnects include Tesseras Wide Area Vertical Expansion, Form Factors Wire on Wafer and Georgia Institute of Technologys Helix interconnects [17-19] as shown in Figure 2.4. Although compliant interconnects can solve the problem of mechanical reliability issue, they are done at the expense of the electrical performance. Since there is a need to reduce the packages parasitic through a decrease line delays, there is a need to minimize the electrical connection length in order to increase the system working frequency. Hence, compliant interconnect may not meet the high electrical frequency requirements of future devices. Figure 2.4: (a) Wide Area Vertical Expansion, (b) Wire on Wafer and (c) G-Helix [17-19] Lead and lead-free solders typically fail mechanical when scaled down to less than to a pitch of 100 mm. Compliant interconnections, on the other hand, do not meet the high frequency electrical requirements. The Microsystems Packaging Research Center at Georgia institute of Technology had demonstrated the feasibility of using re-workable nanostructure interconnections. Aggarwal et al [20] had show that nanostructured nickel interconnections, through a Flip Chip test vehicle, was able to improve the mechanical reliability while maintaining the shortest electrical connection length. However, the main disadvantages of this method was the significant signal loss at high frequency signal of nanocrystalline nickel [21]. As discussed above, nanostructure interconnects technology is the most promising interconnect technology to best meet the stringent mechanical and electrical requirement of next generation devices. However, there is a need of an alternate materials and a sensible choice of materials in this case would be nanocrystalline copper for its high strength material with superior electrical conductivity. Hence, it would be beneficial to use nanocrystalline-copper as material for the nanostructure interconnects. Due to the tendency for the grain to grow, there is a need to stabilize the grain growth in nanocrystalline copper before using it could be considered as a potential candidate for nanostructure interconnect. 2.2 Nanocrystalline material Nanocrystalline materials are polycrystalline materials with an average grain size of less than 100 nm [22]. Over the past decade , new nanocrystalline or nanostructured materials with key microstructural length scales on the order of a few tens of nanometers has been gaining a lot of interest in the material science research society. This is mainly due to its unique and superior properties, as compared to their microcrystalline counterparts which includes increased strength [22] and wear resistance [23]. These unique properties are due to the large volume fraction of atoms at or near the grain boundaries. As a result, these materials have unique properties that are representative of both the grain boundary surface characteristics and the bulk. Recent advances in synthesis and processing methodology for producing nanocrystalline materials such as inert gas condensation [24], mechanical milling [25, 26], electro-deposition [27], and severe plastic deformation [28] have made it possible to produce sufficient nanocrystalline materials for small scale application. 2.2.1 Synthesis Inert gas condensation, the first method used to synthesis bulk nanocrystalline [29], consists of evaporating a metal inside a high-vacuum chamber and then backfilling the chamber with inert gas [30]. These evaporated metal atoms would then collide with the gas atoms, causing them to lose kinetic energy and condenses into powder of small nano-crystals. These powders are then compacted under high pressure and vacuum into nearly fully dense nanocrystalline solids. The grain size distribution obtained from this method is usually very narrow. However, the major draws back of this method are its high porosity levels and imperfection bonding. Grain coarsening also occurs due to the high temperature during the compaction stage [31]. Mechanical milling consists of heavy cyclic deformation in powders until the final composition of the powders corresponds to a certain percentages of the respective initial constituents [25, 26]. A wide grain size distribution is obtained by this method. This technique is a popular method to prepare nanocrystalline materials because of its applicability to any material and simplicity. However, their main drawback includes contamination and grain coarsening during the consolidation stage. Electro-deposition consists of using electrical current to reduce cations of a desired material from a electrolyte solution and coating a conductive object on the substrate. Electro-deposition has many advantages over processing techniques and this includes its applicability to a wide variety of materials, low initial capital investment requirements and porosity-free finished products without a need for consolidation processing [27]. Furthermore, Shen et al. [32] and Lu et al.[33] had recently show that the right electro-deposition condition can produce a highly twinned structure which leads to enhanced ductility. The main drawback of this method is it is the difficulty to achieve high purity. Severe plastic deformation, such as high-pressure torsion, equal channel angular extrusion (ECAE), continuous confined shear straining and accumulative roll-bonding, uses extreme plastic straining to produce nanocrystalline materials by mechanisms such as grain fragmentation, dynamic recovery, and geometric re-crystallization [34]. It is the only technology that transformed conventional macro-grained metals directly into nanocrystalline materials without the need of potentially hazardous nano-sized powders. This is achieved by introducing very high shear deformations into the material under superimposed hydrostatic pressure. Two of the most commonly used methods are high-pressure torsion and ECAE [35]. In the study of the effect of ECAE on the microstructure of nanocrystalline copper, Dalla Torre et al [36] observed that the grains become more equi-axial and randomly orientation as the number of passes increases, as shown in Figure 2.5 Figure 2.5: Microstructure of ECAE copper subjected to (a) 1 passes (b) 2 passes (c) 4 passes (d) 8 passes (e) 12 passes and (f) 16 passes [36] 2.2.2 Mechanical Behavior of nanocrystalline materials Due to the small grain size and high volume fraction of grain boundaries, nanocrystalline materials exhibit significantly different properties and behavior as compared to their microcrystalline counterpart. The structure and mechanical behavior of nanocrystalline materials has been the subject of a lot of researchers interests both experimentally [37-43] and theoretically [44-50]. This section reviews the principal mechanical properties and behavior of nanocrystalline materials. 2.2.2.1 Strength and ductility Recent studies of nanocrystalline metals have shown that there is a five to ten fold increases in the strength and hardness as compared to their microcrystalline state [7, 36, 37, 51, 52]. This increase in the strength is due to the presence of grain boundaries impeding the nucleation and movement of dislocations. Since decreasing grain boundary size increases the number of barrier and the amount of applied stress necessary to move a dislocation across a grain boundary, this resulted in a much higher yield strength. The inverse relationship between grain size and strength is characterized by the Hall-Petch relationship [53, 54] as shown in equation (2.1). Eq (2.1) In equation (2.1), s is the mechanical strength, k is a material constant and d is the average grain size. Hence, nanocrystalline materials are expected to exhibit higher strength as compared to their microcrystalline counterpart. Figure 2.6 and Figure 2.7 show the summary of hardness and yield strength from tensile test that are reported in the literature. Indeed, hardness and yield strength of copper with a grain size of 10nm (3GPa) can be one order higher than their microcrystalline counterpart. To the larger specimens. Derivation from Hall-Petch relationship begins as the grain size approaches 30nm where the stresses needed to activate the dislocation multiplication via Frank-Read sources within the grains are too high and the plastic deformation is instead accommodated by grain boundaries sliding and migration.[12]. Furthermore, as the grain size reduces, the volume fraction of the grain boundaries and the triple points increases. Material properties will be more representative of the grain boundary activity [64] and this will resulting the strength to be inversely proportional to grain size instead of square roots of the grain size as predicted by Hall Petch relation [65]. Further reduction in the grain size will result in grain boundaries processes controlling the plastic deformation and reverse Hall-Petch effect, where the materials soften, will take place. Although sample defects had been account for the earlier experimental observation of reverse Hall-Petch effect[24], Swygenhoven et al [66] and Schiotz et al [47], using molecular simulation, was able to showed that nanocrystalline copper had the highest strength (about 2.3GPa ) at a grain size of 8nm and 10-15nm respectively. Conrad et al [67] pointed out that below this critical grain size, the mechanisms shifted to grain boundary-mediated from dislocation-mediated plasticity and this causes the material to become dependent on strain rate, temperature, Taylor orientation factor and presence of the type of dislocation. The yield stress of nanocrystalline copper was highly sensitive to strain rate even though it is a fcc materials. The strain rate sensitivity, m, in equation 2.2 a engineering parameter which measured the dependency of the strain rate and Figure 2.8 shows a summary of m as a function of grain size for copper specimen in the literature [51, 68-70]. Due to high localized dislocation activities at the grain boundaries which results in enhanced strain rate sensitivities in nanocrystalline materials, m increases drastically when the grain size is below 0.1 mm as shown in Figure 2.8. (2.2) Room temperature strain rate sensitivity was found to dependent on dislocation activities and grain boundaries diffusion [52, 71, 72]. Due to the negligible lattice diffusion at room temperature, the rate limiting process for microcrystalline copper was the gliding dislocation to cutting through forest dislocation, resulting in low strain rate sensitivities. However, due to the increasing presence of obstacles such as grain boundaries for nanocrystalline materials, the rate limiting process for smaller grain size was the interaction of dislocation and the grain boundaries, which is strain rate and temperature dependence. By considering the length scale of the dislocation and grain boundaries interaction, Cheng et al [52] proposed the following model for strain rate sensitivities . (2.3) z is the distance swept by the dislocation during activation, r is the dislocation density and a, a and b are the proportional factors. With this model, they will be able to predict higher strain rate sensitivities for nanocrystalline material produced by severe plastic deformation as compared to other technique. Since the twin boundaries in nanocrystalline or ultra fine grain copper served as a barriers for dislocation motion and nucleation which led to highly localized dislocations near the twin boundaries, the strain rate sensitivity of copper with high density of coherent twin boundaries was found to be higher than those without any twin boundaries [33]. Lastly, the increase enhanced strain rate sensitivity in nanocrystalline copper had been credited for it increases in strength and ductility. For example, Valiev et al [60] credited the enhanced strain rate sensitivity of 0.16 for the high ductility. In addition to a strong dependency on the strain rate, strength in nanocrystalline materials was also highly dependent on the temperature. Wang et al [73] observed that the yield strength for ultra fine grain copper with a grain size of 300nm increases from approximately 370MPa to 500MPa when the temperature reduces from room temperature to 77k. The authors attributed this increase in yield strength due to the absence of additional thermal deformation processes at 77k. This is consistent with Huang et al [74] observation where the temperature dependence of nanocrystalline copper with an increase in hardness of nanocrystalline copper with lowering the temperature is noted Ductility is another important characteristic of nanocrystalline materials. In microcrystalline materials, a reduction in grain size will increase the ductility due to the presence of grain boundaries acting as effective barriers to the propagation of micro-cracks[75]. However, nanocrystalline copper showed a lower strain to failure than that of their microcrystalline counterparts and this lacks in ductility was attributed to the presence of processing defects [76]. Recent advanced in processing of nanocrystalline materials offer materials with fairly good ductility in additional to ultra-high strength. Lu et al [10] reported that nanocrystalline copper with minimal flaw produced via electro-deposition had an elongation to fracture of 30%. Furthermore, Youssef et al [77] observed a 15.5% elongation to failure for defect free nanocrystalline copper produced via mechanical milling. Hence, it was possible for nanocrystalline copper to be both strong and ductile if the processing artifacts are minimized. The failure are usually consists of dimples several time larger than their grain size was normally found on the failure morphology of nanocrystalline materials and Kumar et al [78] presented the following model for initiation and hence the eventual failure of nanocrystalline materials. Furthermore, the presence of shear region was found to be due to shear localization since the ratio of strain hardening rate to prevailing stress was usually small [79, 80]. Figure 2.9: Schematic illustration of fracture in nanocrystalline material postulated by Kumar et al [78] 2.2.2.2 Creeps Nanocrystalline materials are expected to creep during room temperature. This is because Due to the higher fraction of grain boundaries and triple junctions, self diffusivity of nanocrystalline material had been shown to increase by an order of three as compared to microcrystalline copper [81]. Since creep behavior was dependent on grain size and diffusivity, with creep rate increases with an increase in diffusivity or a decrease in grain size, the creep temperature for nanocrystalline copper was known to be a small fraction of melting temperature (about 0.22 of its melting points). Furthermore, since creep had always been cited as one of the reason for grain size softening in nanocrystalline materials, creeps were other important mechanical properties of nanocrystalline materials that had been gaining a lot of researchers attention. Due to the high volume fraction of grain boundaries and enhanced diffusivity rate Model for Predicting Fatigue Life of Nanomaterials Model for Predicting Fatigue Life of Nanomaterials Introduction In the past, the primary function of micro-systems packaging was to provide input/output (I/O) connections to and from integrated circuits (ICs) and to provide interconnection between the components on the system board level while physically supporting the electronic device and protecting the assembly from the environment. In order to increase the functionality and the miniaturization of the current electronic devices, these IC devices have not only incorporated more transistors but have also included more active and passive components on an individual chip. This has resulted in the emerging trend of a new convergent system[1] Currently, there are three main approaches to achieving these convergent systems, namely the system-on-chip (SOC), system-in-package (SIP) and system on package (SOP). SOC seeks to integrate numerous system functions on one silicon chip. However, this approach has numerous fundamental and economical limitations which include high fabrication costs and integration limits on wireless communications, which due to inherent losses of silicon and size restriction. SIP is a 3-D packaging approach, where vertical stacking of multi-chip modules is employed. Since all of the ICs in the stack are still limited to CMOS IC processing, the fundamental integration limitation of the SOC still remains. SOP on the other hand, seeks to achieve a highly integrated microminiaturized system on the package using silicon for transistor integration and package for RF, digital and optical integration[1] IC packaging is one of the key enabling technologies for microprocessor performance. As performance increases, technical challenges increase in the areas of power delivery, heat removal, I/O density and thermo-mechanical reliability. These are the most difficult challenges for improving performance and increasing integration, along with decreasing manufacturing cost. Chip-to-package interconnections in microsystems packages serve as electrical interconnections but often fail by mechanisms such as fatigue and creep. Furthermore, driven by the need for increase the system functionality and decrease the feature size, the International Technology Roadmap for Semi-conductors (ITRS) has predicted that integrated chip (IC) packages will have interconnections with I/O pitch of 90 nm by the year 2018 [2]. Lead-based solder materials have been used for interconnections in flip chip technology and the surface mount technology for many decades. The traditional lead-based and lead-free solder bumps will not satisfy the thermal mechanical requirement of these fine pitches interconnects. These electronic packages, even under normal operating conditions, can reach a temperature as high as 150C. Due to differences in the coefficient of thermal expansion of the materials in an IC package, the packages will experience significant thermal strains due to the mismatch, which in turn will cause lead and lead-free solder interconnections to fail prematurely. Aggarwal et al [3] had modeled the stress experienced by chip to package interconnect. In his work, he developed interconnects with a height of 15 to 50 micrometre on different substrate using classic beam theory. Figure 1 shows the schematic of his model and a summary of some of his results. Although compliant intrerconect could reduces the stress experienced by the interconnect, it is still in sufficient. Chng et al. [4] performed a parametric study on the fatigue life of a solder column for a pitch of 100micrometre using a macro-micro approach. In her work, she developed models of a solder column/bump with a pad size of 50micrometre and heights of 50 micrometre to 200 micrometre. Table I shows a summary of some of her results. Table 1.1: Fatigue life estimation of solder column chip thickness (micrometre) 250 640 640 640 board CTE (ppm/K) 18 18 10 5 solder column height (micrometre) Fatigue life estimation/cycle) 50 81 N.A 171 3237 100 150 27 276 3124 150 134 31 518 4405 200 74 38 273 5772 It can be seen from Table 1.1 that the fatigue lives of all solder columns are extremely short. Apart from the 5ppm/K board where there is excellent CTE matching, the largest fatigue life of the solder column is only about 518 cycles. As expected, the fatigue life increases significantly when the board CTE decreases from 18ppm/K to 10ppm/K and as the height increases from 50micrometre to 200micrometre.This is mainly due to the large strain induced by the thermal mismatch as shown in Figure 1.2. The maximum inelastic principal strain was about 0.16 which exceeds the maximum strain that the material can support. Although the fatigue life of the chip to package interconnection can be increases by increasing the interconnects height, it will not be able to meet the high frequency electrical requirements of the future IC where they need to be operating at a high frequencies of 10-20 GHz and a signal bandwidth of 20 Gbps, By definition, nanocrystalline materials are materials that have grain size less than 100nm and these materials are not new since nanocrystalline materials have been observed in several naturally-occurring specimens including seashells, bone, and tooth enamel [5, 6]. However, the nanocrystalline materials have been attracting a lot of research interest due to its superior mechanical and electrical properties as compared to the coarse-grained counterpart. For example, the nano-crystalline copper has about 6 times the strength of bulk copper [7]. Furthermore, the improvement in the mechanical properties due to the reduction in grain size has been well-documented. Increase in strength due to the reduction in grain-size is predicted by the Hall-Petch relationship which has also been confirmed numerically by Swygenhoven et al [8] and was first demonstrated experimentally by Weertman [9]. The implantation of nanocrystalline copper as interconnect materials seems to be feasible from the processing viewpoint too. Copper has been used as interconnects materials since 1989 whereas nano-copper has also been widely processed using electroplating and other severe plastic deformation techniques in the past few years. For instance, Lu et al. [10] have reported electroplating of nano-copper with grain size less than 100 nm and electrical conductivity comparable to microcrystalline copper. Furthermore, Aggarwal et al [11] have demonstrated the feasibility of using electrolytic plating processes to deposit nanocrystalline nickel as a back-end wafer compatible process. However, there are certain challenges regarding implantation of nanocrystalline copper as interconnects materials. As discussed above, nanocrystalline copper have a high potential of being used as the next generation interconnect for electronic packaging. However, it is vital to understand their material properties, deformation mechanisms and microstructures stability. Although the increase in strength due to the Hall-Petch relationship which has also been confirmed numerically and experimentally by Weertman [9], the improvement in the fatigue properties is not well documented and no model has been established to predict/characterize these nano materials in interconnection application; conflicting results regarding the fatigue properties have also been reported. Kumar et al [12] reported that for nano-crystalline and ultra-fine crystalline Ni, although there is an increase in tensile stress range and the endurance limit, the crack growth rate also increases. However, Bansal et al. [7] reported that with decreasing grain size, the tensile stress range increases but the crack growth rate decreases substantially at the same cyclic stress intensity range. Thus, nanostructured materials can potentially provide a solution for the reliability of low pitch interconnections. However, the fatigue resistance of nanostructured interconnections needs to be further investigated. Since grain boundaries in polycrystalline material increases the total energy of the system as compare to perfect single crystal, it will resulted in a driving force to reduce the overall grain boundary area by increasing the average grain size. In the case of nanocrystalline materials which have a high volume fraction of grain boundaries, there is a huge driving force for grain to growth and this presented a presents a significant obstacle to the processing and use of nanocrystalline copper for interconnect applications. Millet et al [13] have shown, though a series of systematic molecular dynamics simulations, grain growth in bulk nanocrystalline copper during annealing at constant temperature of 800K can be impeded with dopants segregated in the grain boundaries regions. However, it has been observed that stress can trigger grain growth in nanocrystalline materials [14] and there is no literature available on impeding stress assisted grain growth. There is an impending need to investigate the impediment to grain growth caused by the dopant during fatigue/stress assisted grain growth Dissertation Objectives The goal of present project is to develop a model for the fatigue resistance of nano-materials that have been shown to have superior fatigue resistance. Accordingly, the following research objectives are proposed. Develops a model for predicting fatigue life of nanostructured chip-to-package copper interconnections Develops a fundamental understanding on the fatigue behavior of nanocrystalline copper for interconnect application Addresses the issue on the stability of nanocrystalline materials undergoing cyclic loading Overview of the Thesis The thesis is organized so that past research on nanocrystalline materials forms the basis of the understanding and new knowledge discovered in this research. Chapter 2 reviews much of the pertinent literature regarding nanocrystalline materials, including synthesis, deformation mechanisms, and grain growth. Chapter 3 describes a detailed overview of the technical aspects of the molecular dynamics simulation method including inter-atomic potentials, time integration algorithms, the NVT NPT, and NEPT ensembles, as well as periodic boundary conditions and neighbor lists. Include in this chapter is the algorithms for creating nanocrystalline materials used in this dissertations.. Chapter 4 describes the simulation procedure designed to investigate and develop the long crack growth analysis. The results of the long crack growth analysis will be presented at the end of Chapter 4. Chapter 5 presents the result and discussion on mechanical behavior of single and nanocrystalline copper subjected to monotonic and cyclic loading whereas Chapter 6 presents the result and discussion on the impediment to grain growth caused by the dopant during fatigue/stress assisted grain growth. Finally, conclusions and recommendations for future work are presented in Chapter 5. Chapter 2 This chapter offers an expanded summary of the literature published with regards to the fabrication methods, characterization, and properties of nanocrystalline materials in addition to a description of existing interconnect technology. 2.1 Off-Chip Interconnect Technologies Chip-to-package interconnections in microsystems packages serve as electrical interconnections but they will often failed by mechanisms such as fatigue and creep. Furthermore, driven by the need for increase the system functionality and decrease the feature size, the International Technology Roadmap for Semi-conductors (ITRS) has predicted that interconnections of integrated chip (IC) packages will have a I/O pitch of 90 nm by the year 2018 [2]. The International Technology Roadmap for Semiconductors (ITRS) roadmap is a roadmap that semiconductor industry closely follows closely and its projects the need for several technology generations. The package must be capable of meeting these projections in order for it to be successful. This section reviews some of the current interconnect technology. Wire bonding [15] as shown in Figure 2.1, is generally considered as one of the most simple, cost-effective and flexible interconnect technology. The devices on the silicon die are (gold or aluminum) wire bonded to electrically connect from the chip to the wire bond pads on the periphery. However, the disadvantages of wire bonding are the slow rate, large pitch and long interconnect length and hence this will not be suitable for high I/O application. Instead of wires in the wire bonding, tape automated bonding (TAB) is an interconnect technology using a prefabricated perforated polyimide film, with copper leads between chip and substrate. The advantage of this technology is the high throughput and the high lead count. However, it is limited by the high initial costs for tooling. An alternative to peripheral interconnect technology is the area-array solution, as shown in Figure 2.3, that access the unused area by using the area under the chip. In area-array packaging, the chip has an array of solder bumps that are joined to a substrate. Under-fill is then fills the gap between the chip and substrate to enhance mechanical adhesion. This technology gives the highest packaging density methods and best electrical characteristics of all the avaiable interconnection technology. However, not only is its initial cost is high, it requires a very demanding technology to establish and operate. With the need for higher I/O density, compliant interconnects have been developed to satisfy the mechanical requirements of high performance micron sized interconnects. The basic idea is to reduce shear stress experienced by the interconnects through increasing their height or decreasing of its shear modulus (i.e. increases in their compliant) and hence the name compliant interconnects. Some of recent research in compliant interconnects include Tesseras Wide Area Vertical Expansion, Form Factors Wire on Wafer and Georgia Institute of Technologys Helix interconnects [17-19] as shown in Figure 2.4. Although compliant interconnects can solve the problem of mechanical reliability issue, they are done at the expense of the electrical performance. Since there is a need to reduce the packages parasitic through a decrease line delays, there is a need to minimize the electrical connection length in order to increase the system working frequency. Hence, compliant interconnect may not meet the high electrical frequency requirements of future devices. Figure 2.4: (a) Wide Area Vertical Expansion, (b) Wire on Wafer and (c) G-Helix [17-19] Lead and lead-free solders typically fail mechanical when scaled down to less than to a pitch of 100 mm. Compliant interconnections, on the other hand, do not meet the high frequency electrical requirements. The Microsystems Packaging Research Center at Georgia institute of Technology had demonstrated the feasibility of using re-workable nanostructure interconnections. Aggarwal et al [20] had show that nanostructured nickel interconnections, through a Flip Chip test vehicle, was able to improve the mechanical reliability while maintaining the shortest electrical connection length. However, the main disadvantages of this method was the significant signal loss at high frequency signal of nanocrystalline nickel [21]. As discussed above, nanostructure interconnects technology is the most promising interconnect technology to best meet the stringent mechanical and electrical requirement of next generation devices. However, there is a need of an alternate materials and a sensible choice of materials in this case would be nanocrystalline copper for its high strength material with superior electrical conductivity. Hence, it would be beneficial to use nanocrystalline-copper as material for the nanostructure interconnects. Due to the tendency for the grain to grow, there is a need to stabilize the grain growth in nanocrystalline copper before using it could be considered as a potential candidate for nanostructure interconnect. 2.2 Nanocrystalline material Nanocrystalline materials are polycrystalline materials with an average grain size of less than 100 nm [22]. Over the past decade , new nanocrystalline or nanostructured materials with key microstructural length scales on the order of a few tens of nanometers has been gaining a lot of interest in the material science research society. This is mainly due to its unique and superior properties, as compared to their microcrystalline counterparts which includes increased strength [22] and wear resistance [23]. These unique properties are due to the large volume fraction of atoms at or near the grain boundaries. As a result, these materials have unique properties that are representative of both the grain boundary surface characteristics and the bulk. Recent advances in synthesis and processing methodology for producing nanocrystalline materials such as inert gas condensation [24], mechanical milling [25, 26], electro-deposition [27], and severe plastic deformation [28] have made it possible to produce sufficient nanocrystalline materials for small scale application. 2.2.1 Synthesis Inert gas condensation, the first method used to synthesis bulk nanocrystalline [29], consists of evaporating a metal inside a high-vacuum chamber and then backfilling the chamber with inert gas [30]. These evaporated metal atoms would then collide with the gas atoms, causing them to lose kinetic energy and condenses into powder of small nano-crystals. These powders are then compacted under high pressure and vacuum into nearly fully dense nanocrystalline solids. The grain size distribution obtained from this method is usually very narrow. However, the major draws back of this method are its high porosity levels and imperfection bonding. Grain coarsening also occurs due to the high temperature during the compaction stage [31]. Mechanical milling consists of heavy cyclic deformation in powders until the final composition of the powders corresponds to a certain percentages of the respective initial constituents [25, 26]. A wide grain size distribution is obtained by this method. This technique is a popular method to prepare nanocrystalline materials because of its applicability to any material and simplicity. However, their main drawback includes contamination and grain coarsening during the consolidation stage. Electro-deposition consists of using electrical current to reduce cations of a desired material from a electrolyte solution and coating a conductive object on the substrate. Electro-deposition has many advantages over processing techniques and this includes its applicability to a wide variety of materials, low initial capital investment requirements and porosity-free finished products without a need for consolidation processing [27]. Furthermore, Shen et al. [32] and Lu et al.[33] had recently show that the right electro-deposition condition can produce a highly twinned structure which leads to enhanced ductility. The main drawback of this method is it is the difficulty to achieve high purity. Severe plastic deformation, such as high-pressure torsion, equal channel angular extrusion (ECAE), continuous confined shear straining and accumulative roll-bonding, uses extreme plastic straining to produce nanocrystalline materials by mechanisms such as grain fragmentation, dynamic recovery, and geometric re-crystallization [34]. It is the only technology that transformed conventional macro-grained metals directly into nanocrystalline materials without the need of potentially hazardous nano-sized powders. This is achieved by introducing very high shear deformations into the material under superimposed hydrostatic pressure. Two of the most commonly used methods are high-pressure torsion and ECAE [35]. In the study of the effect of ECAE on the microstructure of nanocrystalline copper, Dalla Torre et al [36] observed that the grains become more equi-axial and randomly orientation as the number of passes increases, as shown in Figure 2.5 Figure 2.5: Microstructure of ECAE copper subjected to (a) 1 passes (b) 2 passes (c) 4 passes (d) 8 passes (e) 12 passes and (f) 16 passes [36] 2.2.2 Mechanical Behavior of nanocrystalline materials Due to the small grain size and high volume fraction of grain boundaries, nanocrystalline materials exhibit significantly different properties and behavior as compared to their microcrystalline counterpart. The structure and mechanical behavior of nanocrystalline materials has been the subject of a lot of researchers interests both experimentally [37-43] and theoretically [44-50]. This section reviews the principal mechanical properties and behavior of nanocrystalline materials. 2.2.2.1 Strength and ductility Recent studies of nanocrystalline metals have shown that there is a five to ten fold increases in the strength and hardness as compared to their microcrystalline state [7, 36, 37, 51, 52]. This increase in the strength is due to the presence of grain boundaries impeding the nucleation and movement of dislocations. Since decreasing grain boundary size increases the number of barrier and the amount of applied stress necessary to move a dislocation across a grain boundary, this resulted in a much higher yield strength. The inverse relationship between grain size and strength is characterized by the Hall-Petch relationship [53, 54] as shown in equation (2.1). Eq (2.1) In equation (2.1), s is the mechanical strength, k is a material constant and d is the average grain size. Hence, nanocrystalline materials are expected to exhibit higher strength as compared to their microcrystalline counterpart. Figure 2.6 and Figure 2.7 show the summary of hardness and yield strength from tensile test that are reported in the literature. Indeed, hardness and yield strength of copper with a grain size of 10nm (3GPa) can be one order higher than their microcrystalline counterpart. To the larger specimens. Derivation from Hall-Petch relationship begins as the grain size approaches 30nm where the stresses needed to activate the dislocation multiplication via Frank-Read sources within the grains are too high and the plastic deformation is instead accommodated by grain boundaries sliding and migration.[12]. Furthermore, as the grain size reduces, the volume fraction of the grain boundaries and the triple points increases. Material properties will be more representative of the grain boundary activity [64] and this will resulting the strength to be inversely proportional to grain size instead of square roots of the grain size as predicted by Hall Petch relation [65]. Further reduction in the grain size will result in grain boundaries processes controlling the plastic deformation and reverse Hall-Petch effect, where the materials soften, will take place. Although sample defects had been account for the earlier experimental observation of reverse Hall-Petch effect[24], Swygenhoven et al [66] and Schiotz et al [47], using molecular simulation, was able to showed that nanocrystalline copper had the highest strength (about 2.3GPa ) at a grain size of 8nm and 10-15nm respectively. Conrad et al [67] pointed out that below this critical grain size, the mechanisms shifted to grain boundary-mediated from dislocation-mediated plasticity and this causes the material to become dependent on strain rate, temperature, Taylor orientation factor and presence of the type of dislocation. The yield stress of nanocrystalline copper was highly sensitive to strain rate even though it is a fcc materials. The strain rate sensitivity, m, in equation 2.2 a engineering parameter which measured the dependency of the strain rate and Figure 2.8 shows a summary of m as a function of grain size for copper specimen in the literature [51, 68-70]. Due to high localized dislocation activities at the grain boundaries which results in enhanced strain rate sensitivities in nanocrystalline materials, m increases drastically when the grain size is below 0.1 mm as shown in Figure 2.8. (2.2) Room temperature strain rate sensitivity was found to dependent on dislocation activities and grain boundaries diffusion [52, 71, 72]. Due to the negligible lattice diffusion at room temperature, the rate limiting process for microcrystalline copper was the gliding dislocation to cutting through forest dislocation, resulting in low strain rate sensitivities. However, due to the increasing presence of obstacles such as grain boundaries for nanocrystalline materials, the rate limiting process for smaller grain size was the interaction of dislocation and the grain boundaries, which is strain rate and temperature dependence. By considering the length scale of the dislocation and grain boundaries interaction, Cheng et al [52] proposed the following model for strain rate sensitivities . (2.3) z is the distance swept by the dislocation during activation, r is the dislocation density and a, a and b are the proportional factors. With this model, they will be able to predict higher strain rate sensitivities for nanocrystalline material produced by severe plastic deformation as compared to other technique. Since the twin boundaries in nanocrystalline or ultra fine grain copper served as a barriers for dislocation motion and nucleation which led to highly localized dislocations near the twin boundaries, the strain rate sensitivity of copper with high density of coherent twin boundaries was found to be higher than those without any twin boundaries [33]. Lastly, the increase enhanced strain rate sensitivity in nanocrystalline copper had been credited for it increases in strength and ductility. For example, Valiev et al [60] credited the enhanced strain rate sensitivity of 0.16 for the high ductility. In addition to a strong dependency on the strain rate, strength in nanocrystalline materials was also highly dependent on the temperature. Wang et al [73] observed that the yield strength for ultra fine grain copper with a grain size of 300nm increases from approximately 370MPa to 500MPa when the temperature reduces from room temperature to 77k. The authors attributed this increase in yield strength due to the absence of additional thermal deformation processes at 77k. This is consistent with Huang et al [74] observation where the temperature dependence of nanocrystalline copper with an increase in hardness of nanocrystalline copper with lowering the temperature is noted Ductility is another important characteristic of nanocrystalline materials. In microcrystalline materials, a reduction in grain size will increase the ductility due to the presence of grain boundaries acting as effective barriers to the propagation of micro-cracks[75]. However, nanocrystalline copper showed a lower strain to failure than that of their microcrystalline counterparts and this lacks in ductility was attributed to the presence of processing defects [76]. Recent advanced in processing of nanocrystalline materials offer materials with fairly good ductility in additional to ultra-high strength. Lu et al [10] reported that nanocrystalline copper with minimal flaw produced via electro-deposition had an elongation to fracture of 30%. Furthermore, Youssef et al [77] observed a 15.5% elongation to failure for defect free nanocrystalline copper produced via mechanical milling. Hence, it was possible for nanocrystalline copper to be both strong and ductile if the processing artifacts are minimized. The failure are usually consists of dimples several time larger than their grain size was normally found on the failure morphology of nanocrystalline materials and Kumar et al [78] presented the following model for initiation and hence the eventual failure of nanocrystalline materials. Furthermore, the presence of shear region was found to be due to shear localization since the ratio of strain hardening rate to prevailing stress was usually small [79, 80]. Figure 2.9: Schematic illustration of fracture in nanocrystalline material postulated by Kumar et al [78] 2.2.2.2 Creeps Nanocrystalline materials are expected to creep during room temperature. This is because Due to the higher fraction of grain boundaries and triple junctions, self diffusivity of nanocrystalline material had been shown to increase by an order of three as compared to microcrystalline copper [81]. Since creep behavior was dependent on grain size and diffusivity, with creep rate increases with an increase in diffusivity or a decrease in grain size, the creep temperature for nanocrystalline copper was known to be a small fraction of melting temperature (about 0.22 of its melting points). Furthermore, since creep had always been cited as one of the reason for grain size softening in nanocrystalline materials, creeps were other important mechanical properties of nanocrystalline materials that had been gaining a lot of researchers attention. Due to the high volume fraction of grain boundaries and enhanced diffusivity rate

Celsus Arguments Against Christianity

The first of 4 arguments I believe to be of importance is that of the virgin birth. Jesus claims to be born of a virgin in the town of Bethlehem. It was said that Jesus was born to a virgin and God himself. When it was time for Mary to give birth she and her husband set off to have God’s son. Because there was no room at an Inn Jesus was born in a stable. On the contrary to what the Christian religion believes Celsus says that Jesus was born to a mother who was a spinner, and his legitimate father a Roman soldier, Panthera (Celsus pg. 57). It seemed as if it ere common knowledge the transgressions that Jesus mother had committed with the Roman. When this was found out Jesus mother was cast out by her carpenter husband and convicted of adultery (Celsus pg. 57). The Jews then went on with the story by saying this was explained by the fact that Herod wanted Jesus killed so they fled to Egypt (Celsus pg. 59). Herod feared that the son of God was going to be born and become the rig htful king taking Herod’s throne. Herod sent out a decree that all male babies born would be put to death.Celsus felt that being a God, Jesus should have not been afraid of death, but yet embrace it like the roman Gods did. He was a king after all, and kings were noble, righteous, brave, and willing to die for their subjects. This argument against Jesus seems to be just the beginning, in my opinion, of the downfall of his character. The next point I feel valid to Celsus arguments is that of the Christian faith and their followers. Celsus argued that instead of Jesus wanting all to follow his disciples seemed to pray on the weak and dumb (Celsus pg. 73-75). Jesus followers were the weak, poor, lame, children, and women.This was hardly the kingdom that was respectable. Roman Gods had kingdoms and armies of all kinds. It takes men, women, children, poor and rich to have a community. This was not the case for Christians. Christians used the excuse that those who were educated, se nsible, or wise were evil (Celsus pg. 72). By welcoming only the weak and slow into the Christian fold it looks as if they can only sell their ideas to those who can’t think for themselves. It was like they were more interested in finding followers that were going to follow them no matter the stakes without any sort of challenge. Christianity seemed to be for the lower lass. This is surprising considering that Christianity was met with resistance from the Roman government where a lot of it needed to be done in secrecy. This seems to be a slap in the face to the Romans who encouraged progression and education, yet felt that loyalty was a must. Roman Gods are that of noble character and moral values. They surround themselves with people of the same likeness. Roman Gods were held to a higher standard and were expected to lead their lands with a moral compass and the best interests of everyone. They did not have the luxury of taking risky or even selfish chances.They had to be th e upmost and noblest of leaders to lead their people to a better life Jesus did not seem to follow this thinking, and surrounded himself with ten or eleven friends that he associated with (Celsus pg. 59) that were less than moral men, yet he was gaining followers (Celsus pg. 57). This was very dangerous to Rome. The next argument that seems to be of merit was that of GOD being God. In the reading Celsus makes points that the Christian God is nothing like the Greek and Roman Gods. The Christian God seemed as if he did not have an explanation as to why he let things happen to Good people.He did not have anyone he answered to. The Roman Gods and Kings were the authority of the land, but did not have the right to be reckless with their kingdoms and subjects. The decisions the Romans made affected everyone under their reign, and they made sure that what was done was done in the best interests of all. Not only was it their moral compass, but also an ironclad duty to guide those under thei r authority in the ways of rightness. God did not follow this thinking pattern. God was justified by his followers by saying that it was a test they needed o endure. He was never challenged, or even questioned. Questioning seems to be a bit of taboo. Celsus brings up important points about God being unreachable and unable to save them from harm. My thinking on this was that he was sitting up in the sky watching, but doing nothing. Celsus points out that God keeps his purposes to himself for long periods of time and just stands by when evil overcomes good (Celsus pg. 77). Instead of stopping the suffering that going on he continued to let it happen. He just stood by when plagues, fires, earthquakes, and famines riddled the land.It is hard to fathom God being all knowing and all mighty, yet he sits around and watches as thousands of his followers are killed through these disasters that he could have ceased with a single command or swipe of his hand. It does not seem to be something th at a God with love for his children would let happen if he truly loved them like Christians claim. Instead his followers continued to believe that they just needed to have faith and they would be delivered. For Christians God, in likeness, is thought to be as man is with hands, body, and a voice that he uses to speak to his followers.In fact, it says man is made of God’s likeness and image (Celsus pg. 103). Celsus disagreed with this point wholeheartedly. That is not how God is at all. It was known that the true God in his infinity is without shape or color (Celsus pg. 103). Celsus also showed discord in the fact that God is all powerful, but did nothing to save his own son from torture and death (Celsus pg. 39). Instead of using divine power, he let his son die a humiliating death. Kings and Gods would not have let this happen. They would have protected their own with everything they had, even if this meant their own deaths.The last argument that seemed to have merit for me in this book would have to be that of Christianity being unoriginal, and taken instead from many other religions. Instead of being something original and brought about by itself. The Christian faith is just a melting pot of many other religions and laws. It is said that Moses wrote their history so it reflected them in a positive light. His doctrine was not only held by him, but many other nations and cities such as Egypt, Assyrians, Indians, Persians, Gaul, Getae, and so on (Celsus pg. 55). Many of the laws that are eld by Christianity were given their start by other nations. Even circumcision was said to be started by another society and picked up by the Jews. It seems as if all the facts are more of fables and stories from other people. It is even said that God’s wisdom and man’s goes back to Heracleitus and Plato (Celsus pg. 93). Homer even writes about the Christians beliefs in the afterlife or resurrection. He says â€Å"The gods will take you to the Elysian pla ins at the end of the earth, and there life will be easy† (Celsus pg. 109). This is one of the biggest draws to the Christian faith.Everyone wants to believe that this life is not all there is to life. They want to believe there is life after death. It makes a person feel better about their lives. My point to this is that if the life hereafter is founded on someone else’s principles, what is honest and original about Christianity? I think the thing that was the most eye opening point to me was the fact you always here the prophesy of this God and how he was slapped on a the cheek, and he did nothing in retaliation, except turn the other cheek. Plato shares the same sentiments when he is talking toSocrates in the Crito (Celsus pg. 113).. He talks about never ever doing wrong to someone even if they have avenged us first. He says that in doing that because we were wronged first, it is no different than if we had harmed the person first. Plato says it best in an exerpt â⠂¬Å"So we should never take revenge and never hurt anyone even if we have been hurt† (Celsus pg. 113). I think Celsus was just in thinking Christianity had quite a few flaws in it. Celsus was Looking at it as many should. While they are taught that it is enough to just believe, sometimes that is not enough.Celsus was standing up for his country and his officials. He was putting thought in himself and the rules that were put down. We are taught to stand up for our country. How many times are we led astray by others? Do we simply just take officials word for it that They are doing what is right? I agree with Celsus that you stand for your country and your leaders. I also think and agree that you challenge someone if what they are saying seems to be a bit off. Celsus stood up for his gods and leaders of his country against someone who was threatening their very existence.

Investigating the Effects of Surface Area on the Rate of Reaction Essay

Aim: To study the effects of changing the surface area on the rate of a chemical reaction Hypothesis: This hypothesis is based on the Collision Theory, where in order to react, the two particles involved must: 1. Collide with each other 2. The collision must be energetic enough to overcome the activation energy of the reaction 3. The collision must bring the reactive parts of the molecule into contact the correct way – they must collide with appropriate geometry (the reactive parts) Considering that the surface area of a particle is a factor that mainly affects the collision rate of particles, it would be safe to assume that as the surface area increases, the reaction rate increases. The graph should turn out to be something like this: 1. the reaction is the fastest at the start 2. The reaction is slowing down here 3. No more product is formed Amount of product Time Variables: Variable Factor What is manipulated Dependent Time The time it takes for the reaction to complete depends on the surface area of the compounds being used, because it determines the rate in which the reaction will occur. Independent Volume of the gas collected (H2, CO2) The amount of gas collected for each experiment will depend on the Controlled 1. Mass of Calcium Carbonate (both marble chips and powdered form) 2. Mass of Magnesium (both ribbon and powder) 3. Volume of Hydrochloric Acid 4. Apparatus Used 1. The masses of the substances utilized will remain constantly fixed during the experiment 2. 50 cm3 of HCl will be used for every trial – 550 cm3 in total 3. The apparatus used will remain the same throughout the whole experiment Chemical Reactions: Mg + 2HCl → MgCl2 + H2 1. Magnesium ribbon 2. Hydrogen Gas will be the gas collected 1. 3 Trials will take place 1. Mass of Magnesium ribbon in: 1. Trial 1: 0.064 grams 2. Trial 2: 0.063 grams 3. Trial 3: 0.065 grams CaCO3 + 2HCl → CaCl2 + H2O + CO2 1. Marble Chips 2. Carbon Dioxide will be the gas collected 1. 2 Trials will take place 1. Mass of Marble Chips in: 1. Trial 1: 3.998 grams 2. Trial 2: 3.988 grams Na2CO3 + 2HCl → 2NaCl + H2O + CO2 1. Sodium Carbonate (Powdered) 2. Carbon Dioxide will be the gas collected 1. 2 Trials will take place 1. Mass of Sodium Carbonate 1. Trial 1: 0.504 grams 2. Trial 2: 0.505 grams Apparatus: 1. Eye-Protection – 1 pair of Safety Glasses 2. 1 pair of Scissors 3. 1 Electronic Scale 4. 1 Conical Flask (100cm3) 5. 1 Single-holed rubber bung and delivery tube to fit conical flask 6. 1 Measuring cylinder (100cm3) 7. Stopwatch Chemicals: 1. 12cm of Magnesium Ribbon 2. 550 cm3 of Hydrochloric Acid 3. Marble Chips 4. Sodium Carbonate (Powdered) Method: 1. Set up apparatus as shown 2. Fill the conical flask with 50cm3 of HCl 3. Insert the end of the syringe into the hole on top of the stopper 4. Add the magnesium ribbon 5. Seal the flask with a rubber stopper as quickly as you can, at the same time have someone else present to start the stop watch once the magnesium ribbon has been added to the hydrochloric acid 6. As the reaction takes place, note down the time it takes for the gas collected to reach a multiple of 5 (i.e. 5mL, 10mL †¦.50,55,60,65 etc) 7. Keep measuring until the reaction has stopped, or you are unable to measure anymore 8. Repeat each experiment 3 times, just to be sure the data collected is accurate 9. At step 4, replace the underlined compound with the next compound after one experiment is completed Conclusion Unfortunately I was unable to create a graph using time as the independent variable, because the lab that I had utilized did not have the equipment available to accurately to record the data if time were to be the independent variable. Another factor that played into my decision was the fact that the smallest calibration of the glass syringe I used was 5 cm3. Since the only visible measurements shown on the syringe were multiples of 5, it would only seem reasonable that I switch around the variables, making time the dependent variable, and the volume collected the independent variable, since I couldn’t exactly measure how much gas would be collected every 5 seconds; otherwise the relationship the graph would depict would be completely incorrect. As you can see on the graphs, the slightly steep slopes show when the reaction is the quickest, as it should be in the beginning. The curve shows the reaction slowing down, but unfortunately the curve continues. This is because the reaction is still taking place. I was unable to record the rest of the data because the measuring tools that were available weren’t able to record to such a high degree. In some cases though, like in the powdered sodium carbonate experiment, the reaction began so quickly that I wasn’t able to record the time in most cases, so I just stuck with those that I had managed to note down. In other cases, there were so many distractions in the lab that it was difficult to remain focused. My classmates kept removing some if the items that I was using. The idea was to see how the rate of reaction changed when the surface area of a substance was increased. Initially, my plan was to react magnesium ribbon and magnesium powder with 1 mole of Hydrochloric acid; so I could compare and contrast how the surface area of the substance affected the rate of reaction. I had planned to keep everything about the two substances the same. Its element, mass, the amount of Hydrochloric acid I was going to react with it; the only thing different would be its surface area. Unfortunately the Lab didn’t have any available. So I decided to do the same experiment to Calcium Carbonate, this time using marble chips and powdered calcium carbonate. To my dismay I found that the powdered calcium carbonate wasn’t reacting at all. So I had to change it to sodium carbonate. There is skepticism about using different elements, seeing as they have different orders of reactivity. These factors, including the concentration of the acid used, could also affect the rate of reaction. However, the same acid concentration was used for all experiments, in all trials; so we can dismiss that. However, sodium is much higher up the reactivity series than calcium, which is higher up the reactivity series than magnesium. This is the problem with this experiment; the elements positions in the reactivity series could have really altered the rate of reaction. However, the experiments still prove that when the surface area of a substance is increased, the rate of reaction increases as well. This happens because, when two substances react only the surface particles of the substances can come into direct contact with the reactant particles. Increasing a substance’s surface area, like turning big solid chunks of calcium carbonate into powder, leaves more solid particles available to react. The more particles available to react at one time, the faster the rate of the reaction. Like this: Only atoms on the surface can react If you break the substance down, more atoms are exposed and ready to react. Evaluation Considering the lack of material available, I think I was able to manage the experiment fairly enough to produce results. However, I am not pleased with the factors that may or may not have affected my results, and the circumstances in which I had to switch my variables around. Therefore I would like to state a few things I would like to alter, if ever I got the change to do this experiment again. 1. Apparatus 1. Next time, instead of using a stopwatch, I would like to use a digital device, like a laptop for example, that was somehow connected to the glass syringe, which was programmed to record the volume of the gas collected every 5 seconds. This time the graph would turn out the way it should be. 2. Instead of using a measuring cylinder, I would replace it with a burette, as it takes more accurate measurements of liquids. 1. Chemicals Used 1. I would try and used the same element next time; the only difference would be the surface area. For example, if I used magnesium, to study the effects of surface area on the rate of reaction, I would only you magnesium ribbon and magnesium powder. Studying different elements with different reactivity’s would dismiss any data already collected because an element’s position on the reactivity series may also determine the rate of reaction. Use the same element. 1. Amount of People involved in the experiment 1. If I had to do the experiment again, with the same apparatus, I think I would like to have 3 people participating in the collection of data. 1 person would be watching the syringe rise and call out to record whenever it rose, the 2nd person would time it, and the 3rd person would record it. This time, the data may be even more accurate, because no one is taking their eye off the experiment, like I was doing during my experiment just to record data. I feel that altering these aspects of the experiment would increase the level of accuracy, as to get more substantial data to calculate the order of reaction. Unfortunately with the data I have so far, I am unable to derive the concentrations of the substances I had utilized in my experiment. However, as the objective was to investigate whether or not different surface areas affected the rate of the reaction, I think that I have produced enough data to support my theory.

Ocean pollution essays

Ocean pollution essays Oil pollution is a very large threat to the ocean and it's inhabitants. Roughly about 706 millions of oil pollute ocean waters worldwide each year. Some of the main cause's include oil spills, oil in runoff, air pollution, and even natural seeping of oil into the ocean. In 1987, more than 3.5 million tons of oil were released into the oceans around the world. Out of that only 28 percent of the spillage was accidental; the remaining 72 percent was deliberate, illegal actions. A lot of the illegal pollution is caused by cleaning of oil tanks at sea. After they are cleaned the tankers then dump the polluted water, mixed with all the oil residue, back into the ocean. Blowouts occurring at oil well heads release huge amounts of oil and gas into the ocean. The drilling vessel IXTOTI released more than 400,000 tons of oil into the Gulf of mexico over a period of 9 months after its well exploded in 1978. The most publicized of the oil spills are those caused by tanker accidents. There have been hundreds of accidents involving the spilling of million of tons of oil. Big oil spills, no matter what way they occur, reflect on the oil industry badly. The clean-up cost alone is enormous, and the amount of damages can be into the millions of dollars. Despite the clean-up efforts, once there is an oil spill, it cannot be prevented from causing major damage to wildlife and the environment. All the migrating seabirds like guillemots, puffins, and razorbills are at risk from oil pollution. During migration, they look for calm water where they rest and fish. Oil ©covered seas look calm to birds, and they land on the water by thousands, only to be trapped in the oil and die of starvation. The birds that don't become trapped usually die as well from trying to remove the oil from their feathers, the birds ingest the oil and that usually kills them in a few days. The oil that washes to shore on the beaches where seals and sea lion...

Cherokee Indains essays

Cherokee Indains essays It is Cherokee belief that at first there was only a brother and a sister. The brother hit the sister with a fish, and told her to multiply, so she did. In seven days she gave birth to her first kid. The seven days later she did it again, and again, and again. There were too many children to keep track of them, so they decided to be able to only have one kid a year. The Cherokee first settled in the southeastern portion of the United States in about 1300 A.D. The center of the Cherokee nation was Kituhwa, near Bryson City, NC, so the Cherokee Indians were often referred to as Ani-Kituhwagi, which meant the people of Kituhwa. The Cherokee Indains are a branch of the Iroquois nation. In 1838 the U.S Army made the Cherokee Indians leave their homeland and marched them to "Indian Territory" in what is today Oklahoma. This is now known as the 'Trail of Tears". It is customary for Cherokee Indains to wake up and thank the Creator, to the four directions, to Mother Earth, to Father Sky, and to all of our relations, for the life within you and for all life around you. Thats a part of The Way of the Circle. Kinship and membership in seven clans were decided through the mother, even though women were never considered important. Agriculture relied primarily on corn, beans, and squash and by hunting and gathering wild plants.Cherokee villages were usually independent in daily activities, with the whole tribe only coming together for ceremonies or times of war. Leadership was divided according the circumstances which were : "red" chiefs during war and "white" chiefs in times of peace. Cherokee chanting comes from the slaying of Stone Coat (Nayvnvwi). They speak Atali, Chickamauga, Etali, Onnontiogg, and Qualia. ...

Pathophysiology and Structural Influence Assignment

Pathophysiology and Structural Influence - Assignment Example From regions with low concentration to high, require sodium ion gradient, utilizes energy and involve a movement of polar molecules like glucose and amino acids (Vander et al., 2001). Primary active transport - movement from regions with low concentration to high, requires ATP to function, involves the movement of ions like hydrogen, calcium, sodium, and potassium (Vander et al., 2001). c) Ca-ATPase – this system pumps the calcium ions to the extracellular fluid from the cytoplasm. Besides, in the organelles, it involves pumping of calcium to the lumen of the organelles from the cytoplasm. It utilizes ATP as a source of energy d) Na-K-ATPase – this system pumps two molecules of potassium in the cell while removing three molecules of sodium from the cell through the hydrolysis of energy. This makes the intracellular negative relative to the extracellular environment of the cell (Vander et al., 2001). The difference in charge between the inside and the outside of the cell affects the movement of cations and ions across the membrane. When there is a net charge difference the cations and anions will move in the direction with a low concentration of the molecules until both sides of the cells attain an equilibrium during which the cell would be referred to be in a resting membrane potential (Vander et al., 2001). Monogenetic inheritance is called so because it involves a single genetic disease. The changes in DNA sequence happens at a single genetic code. The modes include X-linked (sex-linked, and sex-limited), autosomal recessive, autosomal dominant, abnormal mitochondrial gene (Vander et al., 2001). Hormonal hyperplasia is a type of abnormal medical condition that involves proliferation of tissues involved in the production of hormones. The proliferation leads to increase in the production of the chemical substances called hormones. In the hormonal hyperplasia, the general structure of the cell or the tissue remains the same even after the proliferation.  

Read one artical from texasisd.com regarding upcoming legislative Article

Read one artical from texasisd.com regarding upcoming legislative Session ) and answer 3 questions in attach file - Article Example By being informed an educator can either chose to weigh in on one side or the other. Additionally, as being an educator, your opinion is valued and it is necessary to be aware of the changes that are taking place within the field as well as have an opinion one way or the other. As a function of being aware of this issue, it is my responsibility to form an opinion as to which side I support in the battle for school choice. Although both sides have salient points which bear repeating, it is without question that enabling school choice will further disenfranchise a large number of at risk and less fortunate children while serving to further help those that are in the least need of help. Bluey, Rob. "VIDEO: The Future Is Brighter With School Choice." The Foundry: Conservative Policy News Blog from The Heritage Foundation. N.p., n.d. Web. 03 Oct. 2012.