953 resultados para Methods of Encryption


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Soluble conducting alkyl polypyrrole polymers have been applied by either chemical polymerization of the 3-alkyl monomers or direct application of polymer emulsion to the surface. Solution, vapor and spray polymerization methods of coating poly(3-alkylpyrroles) to the surface of woven wool fabrics are explored. Conductive textile samples have also been prepared by applying emulsions of soluble prepolymerized 3-alkylpyrrole to the fabric surface. Direct applications of a conductive paint to the textile surface eliminate the exposure of the substrate to damaging oxidizing agents which allow the coating of more sensitive and delicate substrates. All textiles produced are tested for abrasion resistance and conductivity. For alkyl polypyrrole coated fabrics, the optimum carbon chain lengths are between n=10 and n=14, which result in optimum values of conductivity and solubility. The darkness of the tone is inversely related to the surface resistivity of the resulting conductive fabric. Therefore, deep black coatings have low resistivity whereas light gray coatings on a white fabric surface have higher surface resistivity. Longer alkyl chains result in higher surface resistivity in fabrics. The conductive coating of poly(3-decanylpyrrole) on the textile surface has a better abrasion resistance compared to that of an unsubstituted polypyrrole coating.

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In recent times critical approaches to educational policy studies have been subject to increasing interrogation over methodological issues, often by critical policy researchers themselves. In the main, their reflexive posturings have been informed by critique which proceeds that beyond brief descriptions of research logis tics and a general commitment to the methodologies of a critical orientation, critical policy analyses offer few explicit accounts of the connections between the stories they tell about policy and the data used to tell them. As a way of addressing these silences, this paper proposes three methodological approaches within which to explore and explain matters of policy, each generating its own particular view of the (policy) issues worth looking for, where they can be found and how to look for them. Drawing on research into the production of Australian higher education policy during the late 1980s and early 1990s, the paper illustrates the characteristics of these approaches, referring to them as policy historiography, policy genealogy and policy archaeology. Without claiming absolute distinctions between their interests, the paper couples policy historiography with the substantive issues of policy at particular hegemonic moments, policy genealogy with social actors' engagement with policy, and policy archaeology with conditions that regulate policy formations.

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In this article, pre-service teachers' mathematics content knowledge is explored through the analysis of two items about ratio from a Mathematical Competency, Skills and Knowledge Test. Pre-service teachers' thinking strategies, common errors and misconceptions in their responses are presented and discussed. Of particular interest was the range and nature of common incorrect responses for one whole-whole ratio question. Results suggested pre-service teachers had difficulty interpreting a worded multi-step, ratio (scale) question, with errors relating to ratio and/or conversion of measurement knowledge. These difficulties reveal underdeveloped knowledge of mathematical structure and mathematical connections as well as an inability to deconstruct key components of a mathematical problem. Most pre-service teachers also lacked knowledge of standard procedures and methods of solutions.

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The usability of applications designed and developed for mobile devices integral user experience, particularly for current touch-screen mobile devices. This conceptual paper provides a profile of the ways in which mobile device usability evaluation methods are being adapted to better reflect technological. With an increasing capacity for greater user interactivity through a range of tasks and in a variety of contexts, the importance and impact of mobile device context-of-use components is of particular interest to researchers. This requires a need for a shift in evaluation method paradigms with a particular focus on methods involving the user, as part of the overall development process. Having a better understanding of the context-of-use may contribute to improvements in mobile device usability and the overall user experience.

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Fabrication of microfluidic devices has always been a challenging endeavour due to its characteristics and cost involved. Recently, laser ablation using low cost engravers has been exploited for fast and cheap prototyping. In this paper, we explore the various parameters affecting the fabrication of polycarbonate microfluidic channels using CO2 laser ablation. The results show that, by manipulating the focus length of the laser beam, we can achieve good cross sectional profiles with low surface roughness. The results also show that various profiles can be fabricated by changing the laser parameters such as laser power, cutting speed and number of laser pulses.

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Build-up of earwax is a common reason for attendance in primary care. Current practice for earwax removal generally involves the use of a softening agent, followed by irrigation of the ear if required. However, the safety and benefits of the different methods of removal are not known for certain.