By I. Sinikar. Montana Tech. 2018.
Demonstrate your knowledge Writing coursework will have helped prepare you for answering essay questions in an exam buy discount ibuprofen 400mg on-line pain and spine treatment center dworkin. You will still be expected to demonstrate to the examiner the extent of your reading about the subject matter cheap 600mg ibuprofen mastercard menses pain treatment urdu. This will partly be apparent from the range of views and theories you are able to discuss. It will also be demonstrated by your reference to other sources in your answer. You are not usually expected to give a reference list at the end of your answer. Write clearly Exams are handwritten and as students are under pressure to complete the answers as quickly as possible, legibility often suffers. Although you should not slow yourself down by trying to write as neatly as possible, it is still important that the marker can decipher your scribbles. Someone marking around 200 papers will not want to spend ten minutes trying to work out individ ual letters and words. Illegible work is likely to be unmarked, meaning you will lose precious points. Astute editing will also help improve the quality and accuracy of your work. Emergency solutions Sometimes plans go astray and you will need to take emergency action: ° Running out of time – jot down, in note form, the points that would have completed your essay. Indicate you know that the information is from another source by using a general reference like ‘researchers have found’. For example, if you have forgotten the side effects of a drug, describe how you would find them out. Summary Points ° Summative assessments are set at the end of a study unit, term or academic year. It is distinguished from other essays submitted as coursework by its length and detailed treatment of its subject. Each student will make their own choice of topic, unlike set essays where all the students answer the same question. The content of the dissertation will represent the student’s independent study of the subject matter, and will extend beyond the theory and practical applications for merly taught on the course. Writing a dissertation provides the student with an opportunity to: ° study in depth one particular aspect of a subject ° learn the process of academic enquiry ° develop his or her thinking about a specific subject ° deal with a large amount of information ° be able to express ideas coherently ° sustain a discourse throughout a lengthy composition. Choosing a title Unlike set essays, where the question is chosen by the examiner, the stu dent decides on the title for his or her dissertation. Although this is often the most challenging part of the task, it is important to get it right as it will shape both the structure and content of the essay. For instance, some courses con tain advanced study units that involve the completion of a dissertation – so if you are studying ethics, your dissertation will be about some aspect of this. If you have more scope in choosing your topic, you may find Chapter 14 ‘Developing an Idea’ useful. You will have to spend an enormous amount of time and effort in preparing your dissertation. By the completion of your project you may be less than en thusiastic about the work, so start with something that really excites you or has some personal significance for you. This will range from access to the appropriate journals and texts to a tutor who can offer you the appropriate supervision in developing your work. Refining the topic Once you have a general idea of your subject matter, you can start to work at determining the focus of your enquiry. Use a brainstorm (see Chapter 5 ‘Letters and Reports’) or a mind map (see Chapter 11 ‘Assessment’) to gen erate ideas about different aspects of the topic. For example a brainstorm of ‘cross-infection’ might produce the keywords Staphylococcus aureus, antibi otics, wound infections, treatment, infection control measures and methicillin resistant Staphylococcus aureus (MRSA). Once you have narrowed your search to a few keywords, you can start to think about the perspective you will take. Use question stems (Polit and Hungler 1995) to help define your enquiry.
Even the phrase “power operated vehicle” suggests a car or other mode of voluntary transportation buy generic ibuprofen 600 mg online medial knee pain treatment, rather than a wheelchair a person requires for mobility buy 400 mg ibuprofen overnight delivery pain treatment kidney stone. Medicare covers power wheelchairs only when necessary based on the beneﬁciary’s “medical and physical condition. Medicare accepts prescriptions for these wheelchairs only from specialists in physical medicine, orthopedic surgery, neurology, or rheumatology (or from the bene- ﬁciary’s regular physician if specialists are distant or the person’s medical con- dition prevents travel to a specialist). Vendors must have physicians’ prescrip- tions in hand before they supply the equipment. Medicare makes coverage decisions at the national level for important new technologies with widespread implications (for other new interventions, the dozens of contractors that process Part A and B claims around the country make decisions). Major national coverage decisions involve analyzing medical evidence and posting proposed rules in the Federal Register, soliciting public comment. Medicare’s decision to cover liver transplants, for example, took four to ﬁve years. Local Medicare billing contractors make decisions more idiosyncratically, often relying on regional medical opinions rather than ex- plicit evidence. Although Medicare’s policies are still evolving, proposed rules for mak- ing coverage decisions echo medical necessity standards, following four se- quential steps (HCFA 2000b, 31127). Step 1—medical beneﬁt: Does sufficient evidence demonstrate that the item or service medically beneﬁts a deﬁned population? Step 2—added value: For this deﬁned patient population, do medically beneﬁ- cial alternatives exist that are currently covered by Medicare and within the same clinical modality? Step 3—added value: How does the beneﬁt of the item or service compare to the Medicare-covered alternative? Step 4—added value: Will costs of the item or service be equivalent or lower for the Medicare population than the Medicare-covered alternative? Canada’s health-care system differs sig- niﬁcantly from that in the United States: all Canadians have health insurance. Dishonest or disingenuous equipment vendors and therapists undoubt- edly do bilk the system, urging people to purchase unnecessary items or ser- vices. Policies should aim to prevent these abuses, not to withhold needed de- vices or therapies. Along with many other middle-aged people with progressive chronic conditions, Jimmy Howard has not been referred to state vocational rehabilita- tion. Purchases of assistive technology and required training through state vo- cational rehabilitation programs appear idiosyncratic. Numbers represent population estimates from the 1994–95 NHIS-D Phase I for people reporting they will use the equipment for at least 12 months. The NHIS-D gives cross-sectional prevalence estimates—the number of people who experience mobility difficulties—not incidence estimates (the number of people who develop mobility difficulties each year). If a new pro- gram purchased wheelchairs this year for all people with major mobility prob- lems who need them, next year the program would have to buy equipment only for those newly developing difficulties, a much smaller number. These ﬁndings come from the 1994–95 NHIS-D Phase II and are ad- justed for age group and sex. As elsewhere on the Internet, charlatans may misstate or exaggerate claims. The federal National Institute on Disability and Rehabilitation Re- search in the U. Department of Education has a web site that covers a variety of mobility-related topics, including equipment, with the content examined for accuracy (www. Many conditions that impair mobility, such as arthritis, MS, and Parkin- son’s disease, also limit ﬁne-motor movements involving the hands, such as using a keyboard or moving a mouse to position the cursor on the computer screen. Although new technologies allow “hands-free” use of computers, these devices are not widely available, are expensive, and may be affected by speech or language disorders. Percentages for persons with mild and moderate mobility problems are similar to those for people with major difficulties. These projections derive from the Longitudinal Study of Aging and consider six common chronic conditions: arthritis, stroke, diabetes, coronary artery disease, cancer, and confusion. Guide- lines for the Use of Assertive Technology: Evaluation, Referral, Prescrip- tion. Primary Care for Persons with Disabilities: The Internal Medicine Perspective. In Americans with Disabilities: Exploring Implications of the Law for Individ- uals and Institutions, ed.
Whereas initial approaches to mesoporous zeolites relied on larger and larger individual template molecules purchase ibuprofen 600mg line pain management for dogs with pancreatitis, Mobil researchers found that they could use supramolecular assemblies of mole- cules as templates buy ibuprofen 400 mg free shipping advanced pain treatment center jackson tn. They chose long chain quaternary ammonium salts as the micelle forming agent, and reacted Si and Al precursors around these using conditions similar to those for zeolite manufacture: removal of the template micelle, again by calcination, leaves a solid with pores, where the micelles were. These materials, known as MTSs (Micelle Templated Silicas) can be prepared with a range of pore sizes (see Figure 4. As the pore size is essen- tially the diameter of the micelle template, it is easy to estimate the pore size obtained with a given template. For example, a MTS made with a dodecyl trialkylammonium (C12) template would have a pore diameter approximately twice the length of the dodecyl trialkylammonium species – roughly 2. As the chain length of the template molecules decreases, there comes a point where they do not form micelles. This happens around C8, meaning that the smallest pores achievable using this method are around 1. Luckily, this is almost ideal in many ways, since the largest zeolites have pore sizes of c. At the other extreme, as the chain length increases, the ability of the quaternary salt to form micelles decreases, due to lack of solubility, and the largest template molecule which can easily be used is the C18 trialkylammonium salt. This range of sizes is sufﬁciently broad to allow ingress and reaction of many large molecules, but the Mobil researchers managed to increase the pore dimensions even further by expanding the micelle. They did this by inserting hydrophobic mesitylene (trimethylben- zene) molecules into the interior of the micelle. The rationale is that the mesitylene molecules will preferentially exist in the hydrocarbon interior of the micelle, rather than in the aqueous environment outside the micelle, causing the micelle to expand (see Figure 4. MTS materials grown using these expanded micelles have pore sizes from 4. The diagram shows self assembly of the surfactant into micelles followed by condensation of silica around the micelles. After the formation of the silica around the micelles, the micelles are burnt out, leaving pores where the micelles were. The pores are an accurate reﬂection of the size and shape of the micelles. Expansion of a micelle by inclusion of a hydrophobic guest into the hydrophobic interior of the micelles. The interior of the micelle is similarly water-repellent, and thus is a much more comfortable environment for the guest. The incorporation of the guest into the centre of the micelle causes an expansion, which in turn leads to larger pores in the resultant material. Molecules have to diffuse through the pores to feel the effect of the cata- lytic groups which exist in the interior and, after reaction, the reaction products must diffuse out. These diffusion processes can often be the slowest step in the reaction sequence, and thus pores which allow rapid dif- fusion will provide the most active catalysts. It is another feature of the MTSs that they have quite straight, cylindrical pores – ideal for the rapid diffusion of molecules. One ﬁnal extension of the original methodology is that different tem- plates can be used to structure the materials. Two of the most useful systems developed were discovered by Tom Pinnavaia of Michigan State University. These methods allow for the complete recovery of template, so that it can be reused, minimising waste in the preparation of the materi- als, and giving a much greater degree of ﬂexibility to the preparation, allow- ing the incorporation of a great variety of other catalytic groups. More recently, many workers have concentrated on controlling the size and shape of particles, with an eye on industrial applications, where such features must be well deﬁned and controllable. Many shapes have been made, including ﬁbres, spheres, plates, as well as membranes cast on 68 D. All these shapes could one day ﬁnd application, not only in catal- ysis, but in adsorption of e. This chem- istry is based on the fact that the aluminium centres in zeolites cause a negative charge to exist on the framework of the solid; this charge must be balanced by a cation.
However buy ibuprofen 600mg overnight delivery pain medication for dogs with hip problems, the rate of growth in these early experiments was low purchase ibuprofen 600 mg visa knee pain treatment options, and the ﬁlms were impure, containing a large proportion of unwanted graphite. The breakthrough came in the late 1960s, when researchers in the USA discovered that the presence of atomic hydrogen during the deposi- tion process would remove graphite from a surface much faster than diamond. In diamond, every carbon atom is bonded to four others in a strong, rigid tetrahedral structure. This process became known as ‘chemical vapour deposition’ (CVD), since it involves a chemi- cal reaction occurring within a vapour over a surface, leading to deposition of a thin coating onto that surface. Over the next few years more break- throughs were made which allowed diamond ﬁlms to be grown at signiﬁ- cant rates on many useful materials. This series of discoveries stimulated world-wide interest in diamond CVD, in both academia and industry, which continues to the present day. While each method differs in detail, they all share a number of features in common. For example, growth of diamond (rather than graph- ite) normally requires that the precursor gas (usually methane, CH4) is diluted in excess of hydrogen – typically the mixing ratio is 1 per cent methane to 99 per cent hydrogen. Also, the temperature of the substrate is usually greater than 700°C in order to ensure the formation of diamond rather than amorphous carbon. Throttle valves maintain the pressure in the chamber at typically 20–30 torr, while a heater is used to bring the substrate up to a temperature of 700–900°C. The size of the chamber is altered by a sliding barrier to achieve maximum microwave power transfer, which results in a ball of hot, ionised gas (a plasma ball) sitting on top of the heated substrate, onto which the diamond ﬁlm is deposited. The hot ﬁlament is particularly sensitive to oxidising or corrosive gases, and this limits the variety of gas mixtures which can be employed. It is also very difﬁcult to avoid contam- ination of the diamond ﬁlm with ﬁlament material. For diamond to be used in mechanical applications, metallic impurities at the tens of parts per million level are not a signiﬁcant problem, but it becomes unacceptable for electronic applications. Microwave Plasma CVD reactors use very similar conditions to hot ﬁl- ament reactors, and despite being signiﬁcantly more expensive, are now among the most widely used techniques for diamond growth. MAY systems, microwave power is coupled into the chamber in order to create a discharge or plasma. This leads to heating and fragmentation of the gas molecules, resulting in diamond deposition onto a substrate which is immersed in the plasma. Nowadays, microwave powers of up to 60 kW can be utilised in such systems giving growth rates well in excess of 0. As well as high powers and hence higher growth rates, other advantages of microwave systems over other types of reactors are that they can use a wide variety of gas mixtures, including mixtures with high oxygen content, or ones composed of chlorine- or ﬂuorine-containing gases. The fact that no ﬁlament is involved makes microwave systems inherently cleaner than hot ﬁlament systems, and so they have become the system of choice for making diamond for electronic applications. A number of other deposition methods have been used for growing diamond, with varying degrees of success. These include oxyacetylene welding torches, arc jets and plasma torches, laser ablation and liquid phase crystallisation, but none of these yet realistically compete with the hot ﬁlament or microwave systems for reliability and reproducibility. At ﬁrst sight, this may seem like a daunting array of physical and chemical reactions which need to be grasped if diamond CVD is to be understood. But over the past 10 years there have been a large number of studies of the gas phase chemistry, and we are now beginning to obtain a clearer picture of the important principles involved. The ﬁrst clue was that diamond growth appeared to be independent of the chemical nature of the gas phase precursors – it was only the total number of carbons, hydrogens and oxygens in the reactant molecules that mat- tered. This meant that the gas phase chemistry is so rapid that it simply and effectively breaks down the constituent gases to smaller, reactive components. It is now believed that the most critical component in the gas phase mixture is atomic hydrogen, and indeed, this reactive atom drives the whole chemical system. In a hot ﬁlament system, the thermal energy Diamond thin films 81 Figure 5. Schematic representation of the physical and chemical processes occurring during diamond growth. The process gases ﬁrst mix in the chamber before diffusing toward the substrate surface. This activation causes molecules to fragment into reactive radicals and atoms, creates ions and electrons, and heats the gas up to temperatures approaching a few thousand degrees Celsius.