865 resultados para Zero reflection controller
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The function of lipids in human nutrition has been intensively debated in the last decade.This context reinforces the concern about controlling the trans fat ingestion, due to its negative implications on health. Interesterification provides an important alternative to modify the consistency of oils and fats without causing formation of trans isomers. This article reports research done towards production of zero trans fats by chemical interesterification, for different industrial purposes. Aspects related to the effect of trans fats on diet, their impact on health and modifications in Brazilian legislation are also covered.
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A martensitic single crystal Cu-23.95Zn-3.62(wt.%)Al alloy was obtained melting pure Cu, Zn and Al using Bridgman's method. The martensitic phase (monoclinic) can present up to 24 variants, and orienting the surface according to a certain plane is a very hard task. The single crystal was submitted to 8 tons of tension (stress) along the longitudinal direction to reduce the number of variants and facilitate the surface orientation according to the desired plane. This single crystal was oriented using the Laüe back-reflection method to give surfaces with the following oriented crystallographic planes: (010), (120) and (130). It was observed that the tension stress was applied along the [010] direction.
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Signal processing methods based on the combined use of the continuous wavelet transform (CWT) and zero-crossing technique were applied to the simultaneous spectrophotometric determination of perindopril (PER) and indapamide (IND) in tablets. These signal processing methods do not require any priory separation step. Initially, various wavelet families were tested to identify the optimum signal processing giving the best recovery results. From this procedure, the Haar and Biorthogonal1.5 continuous wavelet transform (HAAR-CWT and BIOR1.5-CWT, respectively) were found suitable for the analysis of the related compounds. After transformation of the absorbance vectors by using HAAR-CWT and BIOR1.5-CWT, the CWT-coefficients were drawn as a graph versus wavelength and then the HAAR-CWT and BIOR1.5-CWT spectra were obtained. Calibration graphs for PER and IND were obtained by measuring the CWT amplitudes at 231.1 and 291.0 nm in the HAAR-CWT spectra and at 228.5 and 246.8 nm in BIOR1.5-CWT spectra, respectively. In order to compare the performance of HAAR-CWT and BIOR1.5-CWT approaches, derivative spectrophotometric (DS) method and HPLC as comparison methods, were applied to the PER-IND samples. In this DS method, first derivative absorbance values at 221.6 for PER and 282.7 nm for IND were used to obtain the calibration graphs. The validation of the CWT and DS signal processing methods was carried out by using the recovery study and standard addition technique. In the following step, these methods were successfully applied to the commercial tablets containing PER and IND compounds and good accuracy and precision were reported for the experimental results obtained by all proposed signal processing methods.
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This study investigated the reductive degradation of acetamiprid (5 mg L-1) in aqueous medium (at pH 2.0) induced by zero-valent iron (50 mg). The process was monitored using high-performance liquid chromatography (HPLC) to determine the degradation rate as a function of reaction time, and direct infusion electrospray ionization mass spectrometry (DI-ESI-MS) to search for (and potentially characterize) any possible byproducts formed during degradation. The results obtained via HPLC showed that after 60 min, the degradation of the substrate reached nearly 100% in an acidic medium, whereas the mineralization rate (as determined by total organic carbon measurements) was as low as 3%. Data obtained by DI-ESI-MS showed that byproducts were formed mainly by insertions of hydrogen atoms into the nitrile, imine, and pyridine ring moieties, in addition to the observation of chlorine substitution by hydrogen replacement (hydrodechlorination) reactions.
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Multilevel converters provide an attractive solution to bring the benefits of speed-controlled rotational movement to high-power applications. Therefore, multilevel inverters have attracted wide interest in both the academic community and in the industry for the past two decades. In this doctoral thesis, modulation methods suitable especially for series connected H-bridge multilevel inverters are discussed. A concept of duty cycle modulation is presented and its modification is proposed. These methods are compared with other well-known modulation schemes, such as space-vector pulse width modulation and carrier-based modulation schemes. The advantage of the modified duty-cycle modulation is its algorithmic simplicity. A similar mathematical formulation for the original duty cycle modulation is proposed. The modified duty cycle modulation is shown to produce well-formed phase-to-neutral voltages that have lower total harmonic distortion than the space-vector pulse width modulation and the duty cycle modulation. The space-vector-based solution and the duty cycle modulation, on the other hand, result in a better-quality line-to-line voltage and current waveform. The voltage of the DC links in the modules of the series-connected H-bridge inverter are shown to fluctuate while they are under load. The fluctuation causes inaccuracies in the voltage production, which may result in a failure of the flux estimator in the controller. An extension for upper-level modulation schemes, which changes the switching instants of the inverter so that the output voltage meets the reference voltage accurately regardless of the DC link voltages, is proposed. The method is shown to reduce the error to a very low level when a sufficient switching frequency is used. An appropriate way to organize the switching instants of the multilevel inverter is to make only one-level steps at a time. This causes restrictions on the dynamical features of the modulation schemes. The produced voltage vector cannot be rotated several tens of degrees in a single switching period without violating the above-mentioned one-level-step rule. The dynamical capabilities of multilevel inverters are analyzed in this doctoral thesis, and it is shown that the multilevel inverters are capable of operating even in dynamically demanding metal industry applications. In addition to the discussion on modulation schemes, an overvoltage in multilevel converter drives caused by cable reflection is addressed. The voltage reflection phenomenon in drives with long feeder cables causes premature insulation deterioration and also affects the commonmode voltage, which is one of the main reasons for bearing currents. Bearing currents, on the other hand, cause fluting in the bearings, which results in premature bearing failure. The reflection phenomenon is traditionally prevented by filtering, but in this thesis, a modulationbased filterless method to mitigate the overvoltage in multilevel drives is proposed. Moreover, the mitigation method can be implemented as an extension for upper-level modulation schemes. The method exploits the oscillations caused by two consecutive voltage edges so that the sum of the oscillations results in a mitigated peak of the overvoltage. The applicability of the method is verified by simulations together with experiments with a full-scale prototype.
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The thesis studies possibility of using embedded controller in a crane application and furthermore defines requirements when designing such a controller. Basic crane control architectures are considered and compared. Then embedded controller product life cycle is described: considering such issues like microcontroller selection, software/hardware design and application development tools. Finally, available embedded controller is described and used for implementing crane control.
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O reconhecimento de uma autoridade (de fatos, de observações compartilhadas, de princípios comumente aceitos etc.) por parte de quem se convence é o que buscamos quando nos engajamos em uma prática de oferecer razões para um pensamento ou uma ação. Parece que o ato do reconhecimento é um elemento constitutivo do estado em que temos (ou aceitamos) razões. Por outro lado, muitas vezes estamos inclinados a dizer que temos ou não temos razão; como se, caso a tenhamos, o reconhecimento da autoridade da nossa razão seja compulsório. Por vezes, quando nos movemos no espaço das razões, temos a impressão de que elas já estão lá, de que elas são independentes do nosso melhor julgamento, e o melhor que temos a fazer é aprender a ficar sensíveis a elas. Neste texto examino o realismo quanto a razões como uma formulação do externalismo e considero as conexões entre externalismo em semântica e em epistemologia. Argumento que um realismo quanto a razões pode fazer uso de uma estratégia davidsoniana para conciliar a idéia de que razões estão no mundo com a concepção destas últimas segundo a qual o reconhecimento lhes é constitutivo.
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ABSTRACT Microsprinkler non-pressure compensating nozzles usually show water flow variation along the lateral line. This study aimed at adapting microtubes into non-compensating system of microsprinklers previous installed in the field, as a self-compensated nozzle, to improve the flow uniformity along the lateral line. Microtubes were adapted to three types of commercial microsprinklers. Tests were conducted, both in the laboratory and in field, to evaluate the microsprinkler performance at four different flows (40, 50, 60 and 70 L h-1) under pressure head range from 75 to 245 kPa. Nozzles presented coefficient of flow-rate variation (CVq) lower than 5.5% and distribution uniformity (DU) greater than 95%, which are classified as excellent. The original spatial water distribution of the microsprinkler did not change by using microtube as a nozzle. This device adapted to non-pressure compensating microsprinklers are functional and operate effectively with flows ranging up to 70 L h-1. Small variations at microsprinkler flows along the lateral line can occur, however, at random manner, which is common for pressure-compensating nozzles. Therefore, the microtube technique is able to control pressure variation in microsprinklers.
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Contemporary organisations have to embrace the notion of doing ‘more with less’. This challenges knowledge production within companies and public organisations, forcing them to reorganise their structures and rethink what knowledge production actually means in the context of innovation and how knowledge is actually produced among various professional groups within the organisation in their everyday actions. Innovations are vital for organisational survival, and ‘ordinary’ employees and customers are central but too-often ignored producers of knowledge for contemporary organisations. Broader levels of participation and reflexive practices are needed. This dissertation discusses the missing links between innovation research conducted in the context of industrial management, arts, and culture; applied drama and theatre practices (specifically post-Boalian approaches); and learning – especially organising reflection – in organisational settings. This dissertation (1) explores and extends the role of research-based theatre to organising reflection and reflexive practices in the context of practice-based innovation, (2) develops a reflexive model of RBT for investigating and developing practice-based organisational process innovations in order to contribute to the development of a tool for innovation management and analysis, and (3) operationalises this model within private- and publicsector organisations. The proposed novel reflexive model of research-based theatre for investigating and developing practice-based organisational process innovations extends existing methods and offers a different way of organising reflection and reflexive practices in the context of general innovation management. The model was developed through five participatory action research processes conducted in four different organisations. The results provide learning steps – a reflection path – for understanding complex organisational life, people, and relations amid renewal and change actions. The proposed model provides a new approach to organising and cultivating reflexivity in practice-based innovation activities via research-based theatre. The results can be utilised as a guideline when processing practice-based innovation within private or public organisations. The model helps innovation managers to construct, together with their employees, temporary communities where they can learn together through reflecting on their own and each others’ experiences and to break down assumptions related to their own perspectives. The results include recommendations for practical development steps applicable in various organisations with regard to (i) application of research-based theatre and (ii) related general innovation management. The dissertation thus contributes to the development of novel learning approaches in knowledge production. Keywords: practice-based innovation, research-based theatre, learning, reflection, mode 2b knowledge production
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Objetivos: estudar os fatores prognósticos para o óbito perinatal em gestações com diagnóstico de diástole zero (DZ) ou reversa (DR) na dopplervelocimetria das artérias umbilicais. Métodos: foram analisadas retrospectivamente 204 gestantes com DZ ou DR, sendo realizados os exames de cardiotocografia, perfil biofísico fetal, índice do líquido amniótico e dopplervelocimetria do ducto venoso e das artérias umbilicais, uterinas, aorta e cerebral média. Em 170 casos foi aplicado o modelo de regressão logística para determinar a variável com melhor acurácia na predição do óbito perinatal. Resultados: a mortalidade foi de 28 casos de óbito fetal (13,7%) e 45 de óbito pós-natal (22,1%). Houve correlação significativa entre os óbitos e as variáveis analisadas. A proporção de óbitos no grupo com recém-nascidos de peso inferior a 1.000 g foi de 74,7% e no grupo com idade gestacional inferior a 31 semanas, de 66,3%. Na regressão logística, o peso do recém-nascido foi a melhor variável capaz de predizer o óbito perinatal (p<0,0001), permitindo a elaboração de uma curva de probabilidade de óbito de acordo com esta variável. Conclusões: a DZ ou DR representam um grave comprometimento fetal, cujo risco para óbito perinatal está relacionado principalmente ao peso do RN e à idade gestacional inferior a 31 semanas.
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Objetivos: elaborar modelo matemático baseado em parâmetros da cardiotocografia (CTG) anteparto de repouso para predição da acidose metabólica no nascimento, caracterizada por valores do excesso de bases (BE) inferiores a -10 mEq/L, em gestações com diagnóstico de diástole zero (DZ) ou reversa (DR) na dopplervelocimetria das artérias umbilicais. Métodos: foi estudada a última cardiotocografia de 127 gestantes de alto risco com diagnóstico de DZ ou DR, pela análise visual do traçado. Os parâmetros da CTG estudados foram a variabilidade da FCF, acelerações transitórias, desacelerações e padrão pseudo-sinusoidal. Entre as características da gravidez foram analisadas a idade gestacional, o intervalo em dias entre o diagnóstico da DZ ou DR e o parto. O modelo de regressão logística foi aplicado na determinação do melhor modelo matemático para predição da acidose. Resultados: a acidose metabólica ocorreu em 51 casos (40,2%). O modelo matemático para predição da acidose contemplou os seguintes parâmetros: intervalo em dias entre o diagnóstico da DZ ou DR e o parto (X1), idade gestacional em semanas (X2), variabilidade da FCF <5 bpm (X3) e variabilidade da FCF entre 5 e 9 bpm (X4). As variáveis de análise da variabilidade receberam valor 1 quando presente e valor 0 quando ausente. O coeficiente z foi calculado pela seguinte fórmula: z = 2,2348 + (-0,0117 X1) + (-0,09 X2) + (1,9552 X3) + (-0,4474 X4). Aplicando-se a expressão p = e z/(1 + e z), a probabilidade (p) foi calculada. Conclusões: o modelo matemático apresentado permite calcular a probabilidade da ocorrência de acidose metabólica no nascimento, em gestações com DZ ou DR, a partir da análise visual da cardiotocografia anteparto de repouso.
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OBJETIVO: avaliar os fatores de risco antenatais e pós-natais para o óbito neonatal em gestações com diástole zero (DZ) ou reversa (DR) na doplervelocimetria da artéria umbilical. MÉTODOS: estudo transversal, retrospectivo, inferencial, a partir de 48 prontuários de gestações únicas com DZ ou DR, idade gestacional entre 24 e 34 semanas, em uma maternidade no Nordeste do Brasil. A média de idade foi de 27,3 anos (DP: 7,9). Vinte (41,7%) eram primigestas. Síndromes hipertensivas foram observadas em 44 (91,7%) casos. Trinta e cinco (72,9%) apresentavam DZ e 13 (27,1%) DR. Procedeu-se inicialmente à análise univariada (teste t de Student e teste Exato de Fisher), relacionando os parâmetros com o desfecho avaliado (óbito neonatal). As variáveis que apresentaram associação significativa foram incluídas no modelo de regressão logística (Estatística de Wald). O nível de significância utilizado foi de 5%. RESULTADOS: a mortalidade perinatal foi de 64,6% (31/48). Ocorreram cinco óbitos fetais e 26 neonatais. A média de idade gestacional no momento do diagnóstico foi de 27,9 (DP: 2,8) semanas. A resolução da gestação antes de 24 horas após o diagnóstico ocorreu em 52,1% dos casos. Parto abdominal foi realizado em 85,4% dos casos. Os recém-nascidos pesaram em média 975,9 g (DP: 457,5). Vinte e quatro (57,1%) apresentaram Apgar menor que 7 no primeiro minuto e 21,4%, no quinto. A idade gestacional no momento do diagnóstico, o peso ao nascer e o Apgar de primeiro minuto revelaram-se variáveis significativamente relacionadas com o óbito neonatal (valores de p foram, respectivamente, 0,008; 0,004 e 0,020). As razões de chance foi de 6,6; 25,3 e 13,8 para o óbito neonatal, quando o diagnóstico foi estabelecido até a 28ª semana, peso <1000 g e Apgar < 7, respectivamente. CONCLUSÕES: idade gestacional no momento do diagnóstico, peso ao nascer e Apgar de primeiro minuto foram fatores capazes de predizer o óbito neonatal em gestações com DZ ou DR na doplervelocimetria da artéria umbilical.
Model-View-Controller architectural pattern and its evolution in graphical user interface frameworks
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Model-View-Controller (MVC) is an architectural pattern used in software development for graphical user interfaces. It was one of the first proposed solutions in the late 1970s to the Smart UI anti-pattern, which refers to the act of writing all domain logic into a user interface. The original MVC pattern has since evolved in multiple directions, with various names and may confuse many. The goal of this thesis is to present the origin of the MVC pattern and how it has changed over time. Software architecture in general and the MVC’s evolution within web applications are not the primary focus. Fundamen- tal designs are abstracted, and then used to examine the more recent versions. Prob- lems with the subject and its terminology are also presented.