193 research outputs found

    High-Voltage Resonant Converter with Extreme Load Variation: Design Criteria and Applications

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    The power converter that feeds high-frequency, high-voltage transformers must be carefully designed due to parasitic components, mainly the secondary winding capacitance and the leakage inductance, that introduces resonances in relatively low-frequency range, next to the switching frequency. This paper considers applications in which the load (resistive) has an unpredictable behavior, changing from open to short-circuit condition faster than the output voltage control loop could react. In this context, to avoid over voltage and over current situations, that could damage the converter, the transformer or the load, it is necessary to find an operation point that assure the desired output voltage in spite of the load condition. This can done adjusting the frequency response of the transformer adding an external inductance, together with selecting the switching frequency to get stable output voltage independently of the load

    Sanitation: a set of interventions mandated by the Italian government to limit the spread of SARS-CoV-2 in non-medical facilities

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    There have been several concerns about the environmental persistence of SARS-CoV-2 virus. These concerns led to the formulation of sanitation measures that try to lower the risk of indirect transmission of SARS-CoV-2 in non-medical facilities. This manuscript will elucidate the topic of environmental persistence of SARS-CoV-2. This will benefit the occupational health professionals two-fold. It describes the proper techniques for an effective sanitation of the workplace. It also explains how to protect workers who are responsible for carrying out these interventions. Sanitation is an important measure for a safe workplace. Sanitation is legally established and referenced by all the decrees so far enacted by the Italian government. It is defined as a set of actions and procedures that aim to lower the risk of indirect transmission of SARS-CoV-2 virus

    Caracterização térmica de amido e bagaço de Amaranthus cruentus.

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    O amaranto Ă© um pseudocereal, que produz pequenas sementes de cor amarelo-avermelhado. Foram avaliados o amido e o bagaço de amaranto obtidos no processo de extração. Nas curvas TG/DTG identificouse que o bagaço nĂŁo apresentou perĂ­odo de estabilidade tĂ©rmica, justificado pela composição mais complexa. Com o DSC visualizou-se a ocorrĂȘncia de gelatinização do bagaço, com To e Tp superiores ao amido, porĂ©m, com menor entalpia, apontando um teor residual de amido.Edição dos Anais do 7Âș SimpĂłsio de AnĂĄlise TĂ©rmica, 2015, Bauru

    Effect of treatment with hcl/alcoholic in the modification of corn starch.

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    Corn is the cereal most produced in the world. Corn starches were modified by HCl 0.1 mol L-1 in alcoholic and aqueous solutions. Three mass losses can be observed in the degradation process using TG-DTG curve. The native and treated starches samples don't show differences in the stability region. With DSC curves were observed lower values of the ΔH of gelatinization of the modified starch by HCl in the alcoholic solutions. The modifications using alcoholic solutions demonstrated a good alternative to obtain modifies starches.Edição dos Anais do 7Âș SimpĂłsio de AnĂĄlise TĂ©rmica, 2015, Bauru

    A stochastic view on surface inhomogeneity of nanoparticles

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    The interactions between and with nanostructures can only be fully understood when the functional group distribution on their surfaces can be quantified accurately. Here we apply a combination of direct stochastic optical reconstruction microscopy (dSTORM) imaging and probabilistic modelling to analyse molecular distributions on spherical nanoparticles. The properties of individual fluorophores are assessed and incorporated into a model for the dSTORM imaging process. Using this tailored model, overcounting artefacts are greatly reduced and the locations of dye labels can be accurately estimated, revealing their spatial distribution. We show that standard chemical protocols for dye attachment lead to inhomogeneous functionalization in the case of ubiquitous polystyrene nanoparticles. Moreover, we demonstrate that stochastic fluctuations result in large variability of the local group density between particles. These results cast doubt on the uniform surface coverage commonly assumed in the creation of amorphous functional nanoparticles and expose a striking difference between the average population and individual nanoparticle coverage

    Enteral Glutamine Administration in Critically Ill Nonseptic Patients Does Not Trigger Arginine Synthesis

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    Glutamine supplementation in specific groups of critically ill patients results in favourable clinical outcome. Enhancement of citrulline and arginine synthesis by glutamine could serve as a potential mechanism. However, while receiving optimal enteral nutrition, uptake and enteral metabolism of glutamine in critically ill patients remain unknown. Therefore we investigated the effect of a therapeutically relevant dose of L-glutamine on synthesis of L-citrulline and subsequent L-arginine in this group. Ten versus ten critically ill patients receiving full enteral nutrition, or isocaloric isonitrogenous enteral nutrition including 0.5 g/kg L-alanyl-L-glutamine, were studied using stable isotopes. A cross-over design using intravenous and enteral tracers enabled splanchnic extraction (SE) calculations. Endogenous rate of appearance and SE of glutamine citrulline and arginine was not different (SE controls versus alanyl-glutamine: glutamine 48 and 48%, citrulline 33 versus 45%, and arginine 45 versus 42%). Turnover from glutamine to citrulline and arginine was not higher in glutamine-administered patients. In critically ill nonseptic patients receiving adequate nutrition and a relevant dose of glutamine there was no extra citrulline or arginine synthesis and glutamine SE was not increased. This suggests that for arginine synthesis enhancement there is no need for an additional dose of glutamine when this population is adequately fed. This trial is registered with NTR228

    Dominion cartoon satire as trench culture narratives: complaints, endurance and stoicism

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    Although Dominion soldiers’ Great War field publications are relatively well known, the way troops created cartoon multi-panel formats in some of them has been neglected as a record of satirical social observation. Visual narrative humour provides a ‘bottom-up’ perspective for journalistic observations that in many cases capture the spirit of the army in terms of stoicism, buoyed by a culture of internal complaints. Troop concerns expressed in the early comic strips of Australians, Canadians, New Zealanders and British were similar. They shared a collective editorial purpose of morale boosting among the ranks through the use of everyday narratives that elevated the anti-heroism of the citizen soldier, portrayed as a transnational everyman in the service of empire. The regenerative value of disparagement humour provided a redefinition of courage as the very act of endurance on the Western Front
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