Hot-pressing process modeling for medium density fiberboard (MDF)

In this paper we present a numerical solution for the mathematical modeling of the hot-pressing process applied to medium density fiberboard. The model is based in the work of Humphrey[82], Humphrey and Bolton[89] and Carvalho and Costa[98], with some modifications and extensions in order to take into account mainly the convective effects on the phase change term and also a conservative numerical treatment of the resulting system of partial differential equations.Comment: LaTeX, 11 figures. Added references. Fixed some errors. To appear in International Journal of Mathematics and Mathematical Sciences, http://jam.hindawi.co

Fostering a Culture of Innovation: A Case Study of Elementary School Principals in Costa Rica

To help promote a culture of innovation, the Ministry of Education andthe Ministry of Science, Technology, and Telecommunication of Costa Rica estab-lished a national executive decree requiring all public schools in the country partic-ipate in the National Program of Science and Technology Fairs (NPSTF). This casestudy examines the role of five elementary school principals in Costa Rica in implementing and preparing their schools for the NPSTF initiative. Principals played threesignificant roles: the motivator of teachers and students; acquirer of NPSTF resources;and the organizer of NPSTF committees and coalitions to help train and finance theinitiative. It is recommended the Ministry of Education establish a budget solely ded-icated to support infrastructure and professional development for NPSTF while aligning goals with all stakeholders

Coplanar back contacts for thin silicon solar cells

The type of coplanar back contact solar cell described was constructed with interdigitated n(+) and p(+) type regions on the back of the cell, such that both contacts are made on the back with no metallization grid on the front. This cell construction has several potential advantages over conventional cells for space use namely, convenience of interconnects, lower operating temperatures and higher efficiency due to the elimination of grid shadowing. However, the processing is more complex, and the cell is inherently more radiation sensitive. The latter problem can be reduced substantially by making the cells very thin (approximately 50 micrometers). Two types of interdigitated back contact cells are possible, the types being dependent on the character of the front surface. The front surface field cell has a front surface region that is of the same conductivity type as the bulk but is more heavily doped. This creates an electric field at the surface which repels the minority carriers. The tandem junction cell has a front surface region of a conductivity type that is opposite to that of the bulk. The junction thus created floats to open circuit voltage on illumination and injects carriers into the bulk which then can be collected at the rear junction. For space use, the front surface field cell is potentially more radiation resistant than the tandem junction cell because the flow of minority carriers (electrons) into the bulk will be less sensitive to the production of recombination centers, particularly in the space charge region at the front surface

Clinical phenotypes of SARS-CoV-2 : implications for clinicians and researchers

Patients with COVID-19 present a broad spectrum of clinical presentation. Whereas hypoxaemia is the marker of severity, different strategies of management should be customised to five specific individual phenotypes. Many intubated patients present with phenotype 4, characterised by pulmonary hypoxic vasoconstriction, being associated with severe hypoxaemia with "normal" (>40 mL·cmH2O-1) lung compliance and likely representing pulmonary microvascular thrombosis. Phenotype 5 is often associated with high plasma procalcitonin and has low pulmonary compliance, Which is a result of co-infection or acute lung injury after noninvasive ventilation. Identifying these clinical phenotypes and applying a personalised approach would benefit the optimisation of therapies and improve outcomes

An Observation of Resistance Training History in Ultramarathon Runners and Implications on Performance

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Implementation and Assessment Methodologies of Teachers' Training Courses for STEM Activities

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Functionalized lactic acid macromonomers polycondensation

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