13 resultados para improvements

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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A Summary of different topological arrangements concerning a ZCS-PWM cell is presented, based on the analysis of its application in boost rectifying preregulators, controlled by the technique of instantaneous average values of input current, with the purpose of obtaining high-input-power-factor rectifier and high efficiency in single-phase applications in telecommunication systems. The main characteristics of each switching cell are described, providing conditions to establish a qualitative comparison among the structures. In addition, experimental results are presented for a prototype of the latest version of the ZCS-PWM boost rectifier, implemented for processing normal values of 1200 W output power and 400 V output average voltage, at 220 V Input RMS voltage and 50 kHz switching frequency.

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Integer carrier phase ambiguity resolution is the key to rapid and high-precision global navigation satellite system (GNSS) positioning and navigation. As important as the integer ambiguity estimation, it is the validation of the solution, because, even when one uses an optimal, or close to optimal, integer ambiguity estimator, unacceptable integer solution can still be obtained. This can happen, for example, when the data are degraded by multipath effects, which affect the real-valued float ambiguity solution, conducting to an incorrect integer (fixed) ambiguity solution. Thus, it is important to use a statistic test that has a correct theoretical and probabilistic base, which has became possible by using the Ratio Test Integer Aperture (RTIA) estimator. The properties and underlying concept of this statistic test are shortly described. An experiment was performed using data with and without multipath. Reflector objects were placed surrounding the receiver antenna aiming to cause multipath. A method based on multiresolution analysis by wavelet transform is used to reduce the multipath of the GPS double difference (DDs) observations. So, the objective of this paper is to compare the ambiguity resolution and validation using data from these two situations: data with multipath and with multipath reduced by wavelets. Additionally, the accuracy of the estimated coordinates is also assessed by comparing with the ground truth coordinates, which were estimated using data without multipath effects. The success and fail probabilities of the RTIA were, in general, coherent and showed the efficiency and the reliability of this statistic test. After multipath mitigation, ambiguity resolution becomes more reliable and the coordinates more precise. © Springer-Verlag Berlin Heidelberg 2007.

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Plasma immersion ion implantation (PIII) process is a three dimensional surface modification method that is quite mature and well known to the surface engineering community nowadays, especially to those working in the field of plasma-materials interaction, aiming at both industrial and academic applications. More recently, deposition methods have been added to PIII, the PIII&D, opening possibilities of broader range of applications of these techniques. So, PIII&D is becoming a routine method of surface modification, with the advantage of pushing up the retained dose levels limited by the sputtering due to ion implantation. Therefore, well adherent, thick, three-dimensional films without stress are possible to be achieved, at relatively low cost, using PIII&D. In this paper, we will discuss about a few PIII and PIII&D experiments that have been performed recently to achieve surface improvements in different materials: 1 - high temperature nitrogen PIII in Ti6Al4V alloy in which a deep nitrogen rich treated layer resulted in surface improvements as increase of hardness, corrosion resistance and resistance to wear of the Ti alloy; 2 - nanostructures in ZnO films, obtained by PIII&D of vaporized & ionized Zn source; 3 - combined implantation and deposition of calcium for biomaterial activity of Ti alloy (PIII&D), allowing the growth of hydroxyapatite in a body solution; 4 - magnetron sputtering deposition of Cr that was enhanced by the glow discharge Ar plasma to allow implantation and deposition of Cr on SAE 1070 steel (PIII&D) resulting in surfaces with high resistance to corrosion; and 5 - implantation of nitrogen by ordinary PIII into this Cr film, which improved resistance to corrosion, while keeping the tribological properties as good as for the SAE 1070 steel surface. © 2012 Elsevier B.V.

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The aim of the present study was to analyze the effects of age on cardiorespiratory fitness (CRF), muscle strength and heart rate (HR) response to exercise adaptation in women in response to a long-term twice-weekly combined aerobic and resistance exercise program. 85 sedentary women, divided into young (YG; n=22, 30.3±6.2 years), early middle-aged (EMG; n=28, 44.1±2.5 years), late middle-aged (LMG; n=20, 56.7±3.5 years) and older (OG; n=15, 71.4±6.9 years) groups, had their CRF, muscle strength (1-repetition maximum test) and HR response to exercise (graded exercise test) measured before and after 12 months of combined exercise training. Exercise training improved CRF and muscle strength in all age groups (P<0.05), and no significant differences were observed between groups. Exercise training also improved resting HR and recovery HR in YG and EMG (P<0.05), but not in LMG and OG. Maximal HR did not change in any group. Combined aerobic and resistance training at a frequency of 2 days/week improves CRF and muscle strength throughout the lifespan. However, exercise-induced improvements in the HR recovery response to exercise may be impaired in late middle-aged and older women. © Georg Thieme Verlag KG.

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To identify the critical success factors in the adoption of energy efficiency actions in Brazilian hospitals and describe their behaviour are the objectives of this paper. In order to achieve these goals, a literature review was performed on green management and energy efficiency. This was the basis to define the questions of the interview script applied to two hospitals located in the state of Sao Paulo, Brazil. The interview script application was complemented by secondary data and direct observation. The results showed that: a) the studied hospitals are embracing environmental management actions more often and, whenever possible, energy efficiency actions are taken as well; and b) in the cases analysed top management support, commitment with the environment, green process design and employee empowerment were some of the most relevant critical success factors to the accomplishment of energy efficiency actions. These findings may be of interest to emerging countries, including BRICS (Brazil, Russia, India, China and South Africa).

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The increasing amount of sequences stored in genomic databases has become unfeasible to the sequential analysis. Then, the parallel computing brought its power to the Bioinformatics through parallel algorithms to align and analyze the sequences, providing improvements mainly in the running time of these algorithms. In many situations, the parallel strategy contributes to reducing the computational complexity of the big problems. This work shows some results obtained by an implementation of a parallel score estimating technique for the score matrix calculation stage, which is the first stage of a progressive multiple sequence alignment. The performance and quality of the parallel score estimating are compared with the results of a dynamic programming approach also implemented in parallel. This comparison shows a significant reduction of running time. Moreover, the quality of the final alignment, using the new strategy, is analyzed and compared with the quality of the approach with dynamic programming.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The prevalence of childhood obesity has been increasing worldwide and lifestyle changes are the most important strategies in managing this prevalence. This study aimed to describe the intervention effects of nutrition and physical activities offered as an after school short-term on outcomes of healthy nutrition practices, fitness and lowering fatness. This quasi-experimental study was conducted with a convenience sample of 59 caucasian children, aged 7.7 ± 1.4 years old (52.5% girls) registered on a private school of a middle-size town located in Sao Paulo State, Brazil. The school-based 12-week intervention consisted of 2 weekly 60 minutes section, during 3 months, including a nutritional education and a physical activity curriculum. Anthropometric data was measured for all children at baseline and after 12 weeks. All parents were contacted and requested to complete questionnaire about child’s eating behavior at baseline and after the 12-week program. After the intervention, children showed an increasing in the intake of fruits (64.3%), vegetables (61.9%), and water (52.0%). Overall, 83.3% of the children changed eating behavior according to the questionnaire responded by the parents. Waist circumference was significantly lower and abdominal strength improved after participating in the intervention program. Mean height and weight were significantly higher in boys and girls after a 12-week intervention. Although mean values of BMI remained the same after the intervention it was observed a decreasing in the prevalence of obesity among the children. Thus our study showed that a school-based intervention program focused on nutritional education and physical activity program promoted waist circumference reduction and decreased obesity without affecting the height growth along with improved fitness and healthy eating behavior. This intervention program would be feasible and replicable in others schools around the country.