Análise teórico-experimental do coeficiente de perfomance (COP) de um sistema de refrigeração por jato-compressão

The use of waste heat of energy conversion equipment to produce a cooling effect, consists currently in a very interesting way of efficiency improvement of energy systems. The present research has as intention the theoretical and experimental study of a new intermittent refrigeration system ejector cycle characteristics, with use of waste heat. Initially, was doing a bibliographical survey about the vapor ejector refrigeration system technology. In the following stage was doing a simulation of the corresponding thermodynamic cycle, with preliminarily intention to evaluate the performance of the system for different refrigerants fluids. On the basis of the results of the simulation were selected the refrigerant fluid and developed an experimental group of benches of the refrigeration system considered, where pressure and temperature sensory had been inserted in strategical points of the refrigeration archetype and connected to a computerized data acquisition system for measure the refrigerant fluid properties in the thermodynamic cycle. The test results obtained show good agreement with the literature

Comparação antropométrica, composição corporal, somatotipo e saltos verticais de atletas de voleibol de praia masculino

The kinanthropometric characteristics are used by the sports science as selection criteria and detection of talents. Hence, this study aimed at comparing the anthropometrical profile, the body composition, the somatotype and the vertical jumps of the beach volleyball players. This study consists of 79 male beach volleyball players, being forty nine (n=49) Brazilian participants of the National Circuit and thirty (n=30) of 15 countries participating in the XV Pan American Games. In order to analyze the vertical jumps of the Brazilian the participants were allocated into two groups (G1 and G2) in agreement with the national ranking of their teams. The vertical jump protocol developed by Smith and collaborators was used to evaluate the vertical jumps of spike and block. The Heath-Carter anthropometrical technique (1990) was used for calculating the somatotype. The Student s t test with the Bonferroni adjustment was used to calculate the differences among the investigated variables. The multiple regression analysis was used to identify the contributions of the anthropometrical variables in the performance of the vertical jumps and the multivariance analysis was used to calculate the differences among the components of the somatotype. The Brazilian athletes of G1 were better than G2 in the spike jump (p <0.01), block jump (p <0.01) and in the block difference (p <0.01). The prediction model of the spike jump of G2 included the body mass and standing spike reach (adjusted R2 = 0.77), the body mass and the standing block reach were also included in the model of the block jump (adjusted R2 = 0.73). The regression model of G1 was not statistically significant. As for the somatotype, statistically significant differences were found between the Brazilians and the Pan Americans (Wilks' lambda = 0.498; p <0.05). The Brazilian somatotype was classified as balanced mesomorph (2.7-4.3-3.0) and the Pan American somatotype as endomorphic mesomorph (3.5-4.6-2.4). As to the specific position of the block game (2.8-4.3-2.9) and the defense game (2.6-4.4-3.0), the Brazilian somatotype was classified as balanced mesomorph and the Pan American somatotype, the block (3.7-4.4-2.4) and the defense (3.4-4.9-2.3), was classified as endomorphic mesomorph. In conclusion, the vertical jump height (spike and block) influences the male Brazilian beach volleyball players performance. The physical type of the Brazilian blockers and defenders was similar with relationship to the somatotype. The Brazilian and Pan American beach volleyball players differ in terms of kinanthropometric characteristics. This work had a multidisciplinary feature with the participation of several departments and laboratories, like the Physiotherapy Department, the Nutrition Department, the Physical Education Laboratory, thus corroborating the multidisciplinary research feature

Nanosistemas de penicilina G benzatina para tratamento profilático da febre reumática: estudo analítico

Investigations in the field of pharmaceutical analysis and quality control of medicines require analytical procedures with good perfomance characteristics. Calibration is one of the most important steps in chemical analysis, presenting direct relation to parameters such as linearity. This work consisted in the development of a new methodology to obtain calibration curves for drug analysis: the stationary cuvette one. It was compared to the currently used methodology, and possible sources of variation between them were evaluated. The results demonstrated that the proposed technique presented similar reproducibility compared to the traditional methodology. In addition to that, some advantages were observed, such as user-friendliness, cost-effectiveness, accuracy, precision and robustness. Therefore, the stationary cuvette methodology may be considered the best choice to obtain calibration curves for drug analyis by spectrophotometry

Geometrizando no segundo ciclo :relato de uma intervenção pedagógica voltada à construção de conceitos geométricos no ensino fundamental

This work has proposed to relate the experience product of a pedagogical intervention, performed in a public institution of teaching situated in this capital. It had as objective to validade the applying of a teaching module of geometry, more specifically about the conceptions of perimeter and área in the second cycle of fundamental teaching. This dissertation has presented the problematic which involves the teaching of geometry in different contexts. It has adopted the broach of the radical constructivism while methodological theoretical referencial through which it has tried to explain the phenomena that involves the teaching and the apprenticeship. It appropriates Jean s Piaget contributions related to the development stages, while referencial that will dialogue in the search by sense and comprehension of the geometric apprenticeship process and it runs over Richard s Skemp (1980) theory in order to explicit the student s apprenticeship according to the levels of instrumental comprehesion and relacional comprehension . The research has presented datum related to initial diagnosis evaluantion, the pedagogical intervention and analysis of the activities and students perfomance displaying still the results of the final evaluation. According to the results got, we could check the students group growth front to the acquisition of the concepts of perimeter and área in comparison with the previous knowledges presented in the initial diagnosis evoluation of the students participants of the research. We have concluded evaluating the objectives of the research, connecting the strategies and reasoning employed by the students in order to resolve the questions and then to reach the objectives proposed by the teaching module. We have presented still the main obstacles to the apprenticeship of such concepts

Análise da situação de trabalho do motorista em uma empresa de ônibus urbano da idade de Natal (RN)

The problem dealt with in this study concerns the analysis of bus drivers' working situation. It stemmed from the need to identify the difficulties faced by these professionals in accomplishing the results expected by the company. A case study was carried out in a public transportation company in the city of Natal. Records and observations made in the workplace, alongside perfomance indicators, such as absenteeism tax, staff turnover and traffic accidents, revealed problems in their activity. It was made clear that, in the company being studied, absenteeism was related to health problems, particularly psychiatric and musculoskeletal disorders, and that although the indicators of traffic accidents and staff turnover have declined over the years, they are still elevated. The interviews involved 50 of the 124 drivers who worked directly in the service, and contained questions covering eleven factors related to the drivers' work. They indicated a gap between the prescribed work and the work actually done, in that there were a series of embarassing or stressful situations involving traffic, itinerary length, road conditions, vehicle maintenance, physical environment (bus terminus), job post and supervision policies. On the other hand, factors such as enjoying driving, the work itself and being with workmates positively influenced the drivers' working conditions. In the propositions of the administration and human resources subsystems, some alternatives were found in order to remodel this activity

Utilizando Pesos estáticos e dinâmicos em sistemas multi-classificadores com diferentes níveis de diversidade

Although some individual techniques of supervised Machine Learning (ML), also known as classifiers, or algorithms of classification, to supply solutions that, most of the time, are considered efficient, have experimental results gotten with the use of large sets of pattern and/or that they have a expressive amount of irrelevant data or incomplete characteristic, that show a decrease in the efficiency of the precision of these techniques. In other words, such techniques can t do an recognition of patterns of an efficient form in complex problems. With the intention to get better performance and efficiency of these ML techniques, were thought about the idea to using some types of LM algorithms work jointly, thus origin to the term Multi-Classifier System (MCS). The MCS s presents, as component, different of LM algorithms, called of base classifiers, and realized a combination of results gotten for these algorithms to reach the final result. So that the MCS has a better performance that the base classifiers, the results gotten for each base classifier must present an certain diversity, in other words, a difference between the results gotten for each classifier that compose the system. It can be said that it does not make signification to have MCS s whose base classifiers have identical answers to the sames patterns. Although the MCS s present better results that the individually systems, has always the search to improve the results gotten for this type of system. Aim at this improvement and a better consistency in the results, as well as a larger diversity of the classifiers of a MCS, comes being recently searched methodologies that present as characteristic the use of weights, or confidence values. These weights can describe the importance that certain classifier supplied when associating with each pattern to a determined class. These weights still are used, in associate with the exits of the classifiers, during the process of recognition (use) of the MCS s. Exist different ways of calculating these weights and can be divided in two categories: the static weights and the dynamic weights. The first category of weights is characterizes for not having the modification of its values during the classification process, different it occurs with the second category, where the values suffers modifications during the classification process. In this work an analysis will be made to verify if the use of the weights, statics as much as dynamics, they can increase the perfomance of the MCS s in comparison with the individually systems. Moreover, will be made an analysis in the diversity gotten for the MCS s, for this mode verify if it has some relation between the use of the weights in the MCS s with different levels of diversity