996 resultados para Técnicas de intensificação compostas


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Compararam-se as dificuldades transcirúrgicas e as complicações pós-operatórias das técnicas guilhotina (TG) e stripping (TS) para a neurectomia digital em eqüinos. Sob anestesia com halotano, quatro éguas tiveram os nervos digitais de um dos membros torácicos e um dos pélvicos submetidos à TG, enquanto os nervos digitais dos membros colaterais foram submetidos à TS. Os tempos cirúrgicos médios de TG e TS foram semelhantes. O comprimento médio do fragmento do nervo removido foi três vezes maior em TS (P<0,001). Independente da técnica utilizada, houve perda total da sensibilidade nos talões de todos os membros dentro dos quatro primeiros meses da cirurgia. Após 14 meses, houve retorno da sensibilidade em 37% dos membros em TG e 18,8% em TS (P=0,06). Ao exame de palpação para identificação de neuromas dolorosos, houve episódios de sensibilidade discreta em um maior número de cotos nervosos proximais operados com TS, 53,6% contra 6,4% dos operados com TG (P=0,003). Ambas as técnicas foram satisfatórias por não apresentarem maiores complicações durante ou após a cirurgia. Considerou-se que TG apresentou menor potencial para produzir reinervação e neuromas dolorosos.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Na bovinocultura brasileira, a vacinação contra o vírus da Febre Aftosa (FA) é fundamental para a fase inicial de erradicação da enfermidade. Mesmo a qualidade da vacina tendo controle rígido feito pelos órgãos oficiais, restam variáveis técnicas ainda não monitoradas como manipulação, transporte e conservação pelo consumidor, dose, local e forma de aplicação que interferem na resposta imune, preocupações essas, que direcionam o presente estudo. Assim, pela pesquisa de anticorpos neutralizantes do vírus da FA em placas de microtitulação com cultivo de células BHK-21, foram determinados os títulos, calculados em logaritmo decimal (SN), em soros sanguíneos de bovinos vacinados conforme o protocolo apresentado. No primeiro grupo com 25 animais, a média de SN foi igual a 2,37 e 2,19, respectivamente, 30 e 180 dias após a vacinação, cuja vacina foi manejada por especialista com todos os cuidados técnicos recomendados. Outro grupo com 140 bovinos, distribuídos em 5 fazendas distintas, apresentou média de SN igual a 1,66 e 1,5l depois de 30 e 180 dias após a vacinação, cuja vacina foi manejada sem acompanhamento técnico e por indivíduos não especializados. Finalmente um terceiro grupo com 10 animais, que ficaram sem vacinação, apresentou média de SN igual a 0,82 e 0,81, também 30 e 180 dias após a aplicação do placebo. Assim, só os cuidados com a qualidade da vacina são insuficientes para proporcionar títulos satisfatórios que determinam proteção dos rebanhos contra o vírus da FA, uma vez que a literatura pertinente considera rebanhos com 1,52 de média do SN como tendo 50% dos animais protegidos, e com 1,70 como tendo mais de 70% de proteção, no período de até 7 meses.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Analyze the work of the school manager who now faces the changes experienced in school management for the last two decades. We propose that there have been changes in school management that have generated a larger number of activities to be developed by managers, causing both the intensification of work and a greater involvement of professionals in the financial-administrative dimension of their work in opposition to the political and pedagogical dimension. This study has a historic-critic approach. That is why we performed semi-structured interviews with school managers of the city schools in Natal RN, BR as a methodological procedure. We also analyzed the literature as well as the documentation relevant to this subject. From the study it was possible to conclude that changes in the field of school management and also teaching have led to an intensification of work of school managers and that such changes have not been followed by corresponding improvement in working conditions and teaching career of these professionals. They, as a rule, are considered by controlling agencies and by the school community as the primarily responsible for the school condition and for creating actions or projects that may improve the institutional objectives and results, including even the maintenance of the institution. Moreover, the growing number of administrative activities represents for obvious reasons extra work for these managers, who, when trying to cope with the growing bureaucratic situations, end up misplacing other political and educational aspects of school work, which may undermine the final purpose of school itself. We stress that we must broaden the discussions on the functions of the school manager, so that this worker can actualize a pedagogical project more committed to an emancipatory nature, despite all the challenge in keeping the school running in often-precarious conditions

Relevância:

20.00% 20.00%

Publicador:

Resumo:

O conhecimento da variação espacial de atributos do solo pode contribuir para o planejamento e a otimização na condução de experimentos e de lavouras comerciais, objetivando a agricultura de precisão. O objetivo deste trabalho foi avaliar a necessidade de fertilizante e calcário para implantação da agricultura de precisão, com base no comportamento espacial de atributos químicos de um Latossolo após o corte da cana-planta. Os dados foram avaliados pela estatística descritiva e análise da dependência espacial, com base no ajuste de semivariogramas. As técnicas de geoestatísticas apresentam-se como ferramentas auxiliares na aplicação de fertilizantes por meio de taxa variada, detectando, para a área em estudo, que não se recomenda a aplicação de fósforo e calagem por taxa variada.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The search for cultural heritage preservation should be a constant, in order to minimize the lost of historical and cultural identity of a country. As part of this cultural heritage, highlights the importance of historical buildings. For the principles of restoration are met its important to know the state of conservation and the existing materials. Given the above, this work aims to study the pathological manifestations of the mortar coating from the Grupo Escolar Augusto Severo. For this, was conducted historical survey of the building, on-site visits with visual observation, collecting samples of mortar coating and characterization through visual and laboratory analysis, XRF, XRD, TG/DTG, OM and SEM-EDS. From the observations, pathological manifestations were found as: cracks, detachment of the coating, dirt, use of inappropriate material basis of cement, efflorescence, mold and mildew and also incompatible material base of cement. It was found that the pathological manifestations were intensified due to lack of coverage in some spots and especially the abandonment of the building, that many years does not have restoration or any other type of preventive and corrective maintenance. The results of laboratory tests indicated that the mortars studied are based on lime, with calcitic nature, and siliceous aggregate, with the presence of clay in two samples. From the samples collected, two are composed of lime, sand and clay and two by lime and sand. In this regard, it is important to conduct periodic inspections and maintenance, as well as carrying out restoration with use of material compatible with the original

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Nowadays, telecommunications is one of the most dynamic and strategic areas in the world. Organizations are always seeking to find new management practices within an ever increasing competitive environment where resources are getting scarce. In this scenario, data obtained from business and corporate processes have even greater importance, although this data is not yet adequately explored. Knowledge Discovery in Databases (KDD) appears then, as an option to allow the study of complex problems in different areas of management. This work proposes both a systematization of KDD activities using concepts from different methodologies, such as CRISP-DM, SEMMA and FAYYAD approaches and a study concerning the viability of multivariate regression analysis models to explain corporative telecommunications sales using performance indicators. Thus, statistical methods were outlined to analyze the effects of such indicators on the behavior of business productivity. According to business and standard statistical analysis, equations were defined and fit to their respective determination coefficients. Tests of hypotheses were also conducted on parameters with the purpose of validating the regression models. The results show that there is a relationship between these development indicators and the amount of sales

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this work is to draw attention to the importance of use of techniques of loss prevention in small retail organization, analyzing and creating a classification model related to the use of these in companies. This work identifies the fragilities and virtues of companies and classifies them relating the use of techniques of loss prevention. The used methodology is based in a revision of the available literature on measurements and techniques of loss prevention, analyzing the processes that techniques needed to be adopted to reduce losses, approaching the "pillars" of loss prevention, the cycle life of products in retail and cycles of continues improvement in business. Based on the objectives of this work and on the light of researched techniques, was defined the case study, developed from a questionnaire application and the researcher's observation on a net of 16 small supermarkets. From those studies a model of classification of companies was created. The practical implications of this work are useful to point mistakes in retail administration that can become losses, reducing the profitability of companies or even making them impracticable. The academic contribution of this study is a proposal of an unpublished model of classification for small supermarkets based on the use of techniques of loss prevention. As a result of the research, 14 companies were classified as Companies with Minimum Use of Loss Prevention Techniques - CMULPT, and 02 companies were classified as Companies with Deficient Use of Loss Prevention Techniques - CDULPT. The result of the research concludes that on average the group was classified as being Companies with Minimum Use of Techniques of Prevention of Losses EUMTPP, and that the companies should adopt a program of loss prevention focusing in the identification and quantification of losses and in a implantation of a culture of loss prevention

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The objective of this work was to investigate the factors that inhibit the use of Environmental Techniques in the Gas Station of the city of Natal/RN. For this, a survey with the aid of a questionnaire was used like research instrument. It s used a sample for convenience, not probabilistic. For collection of the data, it was used directly application of the questionnaire to the Managers or Assistant managers of the gas station, in accordance with its availability or presence. The data was collected in all the regions of Natal (North, South, East and West). The population in accordance with the data of the ANP of September 2005 is of 111 ranks and the collected sample was of 86. To carry through the analysis of the data of this research had been used softwares Excel and Statistic version 5.0, for Windows. The analysis of data is divided in two parts; descriptive analysis and analysis of groupings (clusters). The results showed that bigger part of the interviewed ones has between 30 and 39 years of age; they have second grade completed; they had declared to have little between and reasonable knowledge how much to the use of Clean Technology (CT) in gas station; and a small part of the interviewed ones had informed to have much knowledge how much the resolutions of the CONAMA established for the Gas Station. Of the searched ranks, the majority is national(76.7%); the most accurate practice environmental used in the gas station are: it collects selective of oil used or contaminated and ecological tanks - coated with strengthened fibre glass; great part of the interviewed ones (33.8%) informed that never the TL makes planning of referring future action; about of the half of the interviewed ones (84.9%) they had more declared that its employees have of none to a reasonable level of training for deal with problems that compromise the environment; the majority of the ranks (72.1%) functions has for more then six years. It is observed that almost all the interviewed ones (96.5%) evaluate as being important or very important the implantation of CT in Gas Station and the great majority (82.1%) evaluates the difficulty in if implanting these technologies in Gas Station as being easy or very easy. In the analysis of cluster, it was verified existence of two groupings (as much in the variable of the barriers and benefits), being that inside of each clusters exists homogeneity and between clusters exists heterogeneity. In reality, everything is important or very important in the opinion of the interviewed ones. There only exists a small significant difference that separates them in clusters

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The usual programs for load flow calculation were in general developped aiming the simulation of electric energy transmission, subtransmission and distribution systems. However, the mathematical methods and algorithms used by the formulations were based, in majority, just on the characteristics of the transmittion systems, which were the main concern focus of engineers and researchers. Though, the physical characteristics of these systems are quite different from the distribution ones. In the transmission systems, the voltage levels are high and the lines are generally very long. These aspects contribute the capacitive and inductive effects that appear in the system to have a considerable influence in the values of the interest quantities, reason why they should be taken into consideration. Still in the transmission systems, the loads have a macro nature, as for example, cities, neiborhoods, or big industries. These loads are, generally, practically balanced, what reduces the necessity of utilization of three-phase methodology for the load flow calculation. Distribution systems, on the other hand, present different characteristics: the voltage levels are small in comparison to the transmission ones. This almost annul the capacitive effects of the lines. The loads are, in this case, transformers, in whose secondaries are connected small consumers, in a sort of times, mono-phase ones, so that the probability of finding an unbalanced circuit is high. This way, the utilization of three-phase methodologies assumes an important dimension. Besides, equipments like voltage regulators, that use simultaneously the concepts of phase and line voltage in their functioning, need a three-phase methodology, in order to allow the simulation of their real behavior. For the exposed reasons, initially was developped, in the scope of this work, a method for three-phase load flow calculation in order to simulate the steady-state behaviour of distribution systems. Aiming to achieve this goal, the Power Summation Algorithm was used, as a base for developing the three phase method. This algorithm was already widely tested and approved by researchers and engineers in the simulation of radial electric energy distribution systems, mainly for single-phase representation. By our formulation, lines are modeled in three-phase circuits, considering the magnetic coupling between the phases; but the earth effect is considered through the Carson reduction. It s important to point out that, in spite of the loads being normally connected to the transformer s secondaries, was considered the hypothesis of existence of star or delta loads connected to the primary circuit. To perform the simulation of voltage regulators, a new model was utilized, allowing the simulation of various types of configurations, according to their real functioning. Finally, was considered the possibility of representation of switches with current measuring in various points of the feeder. The loads are adjusted during the iteractive process, in order to match the current in each switch, converging to the measured value specified by the input data. In a second stage of the work, sensibility parameters were derived taking as base the described load flow, with the objective of suporting further optimization processes. This parameters are found by calculating of the partial derivatives of a variable in respect to another, in general, voltages, losses and reactive powers. After describing the calculation of the sensibility parameters, the Gradient Method was presented, using these parameters to optimize an objective function, that will be defined for each type of study. The first one refers to the reduction of technical losses in a medium voltage feeder, through the installation of capacitor banks; the second one refers to the problem of correction of voltage profile, through the instalation of capacitor banks or voltage regulators. In case of the losses reduction will be considered, as objective function, the sum of the losses in all the parts of the system. To the correction of the voltage profile, the objective function will be the sum of the square voltage deviations in each node, in respect to the rated voltage. In the end of the work, results of application of the described methods in some feeders are presented, aiming to give insight about their performance and acuity

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Techniques of optimization known as metaheuristics have achieved success in the resolution of many problems classified as NP-Hard. These methods use non deterministic approaches that reach very good solutions which, however, don t guarantee the determination of the global optimum. Beyond the inherent difficulties related to the complexity that characterizes the optimization problems, the metaheuristics still face the dilemma of xploration/exploitation, which consists of choosing between a greedy search and a wider exploration of the solution space. A way to guide such algorithms during the searching of better solutions is supplying them with more knowledge of the problem through the use of a intelligent agent, able to recognize promising regions and also identify when they should diversify the direction of the search. This way, this work proposes the use of Reinforcement Learning technique - Q-learning Algorithm - as exploration/exploitation strategy for the metaheuristics GRASP (Greedy Randomized Adaptive Search Procedure) and Genetic Algorithm. The GRASP metaheuristic uses Q-learning instead of the traditional greedy-random algorithm in the construction phase. This replacement has the purpose of improving the quality of the initial solutions that are used in the local search phase of the GRASP, and also provides for the metaheuristic an adaptive memory mechanism that allows the reuse of good previous decisions and also avoids the repetition of bad decisions. In the Genetic Algorithm, the Q-learning algorithm was used to generate an initial population of high fitness, and after a determined number of generations, where the rate of diversity of the population is less than a certain limit L, it also was applied to supply one of the parents to be used in the genetic crossover operator. Another significant change in the hybrid genetic algorithm is the proposal of a mutually interactive cooperation process between the genetic operators and the Q-learning algorithm. In this interactive/cooperative process, the Q-learning algorithm receives an additional update in the matrix of Q-values based on the current best solution of the Genetic Algorithm. The computational experiments presented in this thesis compares the results obtained with the implementation of traditional versions of GRASP metaheuristic and Genetic Algorithm, with those obtained using the proposed hybrid methods. Both algorithms had been applied successfully to the symmetrical Traveling Salesman Problem, which was modeled as a Markov decision process

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study presents a description of the development model of a representation of simplified grid applied in hybrid load flow for calculation of the voltage variations in a steady-state caused by the wind farm on power system. Also, it proposes an optimal load-flow able to control power factor on connection bar and to minimize the loss. The analysis process on system, led by the wind producer, it has as base given technician supplied by the grid. So, the propose model to the simplification of the grid that allows the necessity of some knowledge only about the data referring the internal network, that is, the part of the network that interests in the analysis. In this way, it is intended to supply forms for the auxiliary in the systematization of the relations between the sector agents. The model for simplified network proposed identifies the internal network, external network and the buses of boulders from a study of vulnerability of the network, attributing them floating liquid powers attributing slack models. It was opted to apply the presented model in Newton-Raphson and a hybrid load flow, composed by The Gauss-Seidel method Zbarra and Summation Power. Finally, presents the results obtained to a developed computational environment of SCILAB and FORTRAN, with their respective analysis and conclusion, comparing them with the ANAREDE

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Artificial Intelligence techniques are applied to improve performance of a simulated oil distillation system. The chosen system was a debutanizer column. At this process, the feed, which comes to the column, is segmented by heating. The lightest components become steams, by forming the LPG (Liquefied Petroleum Gas). The others components, C5+, continue liquid. In the composition of the LPG, ideally, we have only propane and butanes, but, in practice, there are contaminants, for example, pentanes. The objective of this work is to control pentane amount in LPG, by means of intelligent set points (SP s) determination for PID controllers that are present in original instrumentation (regulatory control) of the column. A fuzzy system will be responsible for adjusting the SP's, driven by the comparison between the molar fraction of the pentane present in the output of the plant (LPG) and the desired amount. However, the molar fraction of pentane is difficult to measure on-line, due to constraints such as: long intervals of measurement, high reliability and low cost. Therefore, an inference system was used, based on a multilayer neural network, to infer the pentane molar fraction through secondary variables of the column. Finally, the results shown that the proposed control system were able to control the value of pentane molar fraction under different operational situations

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Neste trabalho, são utilizadas a Técnica da Ressonância Transversa (TRT) e a Técnica da Ressonância Transversa Modificada (MTRT), para a determinação das freqüências dos modos ressonantes de antenas de microfita com patch quadrado, retangular e circular e com substratos isotrópicos e anisotrópicos. Para isso, é proposto um modelo da cavidade equivalente, onde a antena tipo patch retangular é representada como sendo a superposição de duas linhas infinitas em microfita, uma de largura W, representando a dimensão que expressa a largura do patch, e a outra com largura L, representando a dimensão que expressa o comprimento do patch. A avaliação da eficiência e aplicabilidade dos métodos citados é realizada comparando-se com resultados experimentais e obtidos através de outras técnicas. Três situações serão verificadas: estruturas com substrato infinito, estrutura com substrato tipo pedestal e estruturas com substrato truncado além dos limites da fita metálica. Os resultados obtidos demonstram que as técnicas de análise de onda completa utilizadas neste trabalho, por um formalismo matemático mais rigoroso, são eficientes e precisas tanto na aplicação em estruturas com substrato isotrópico como nas que possuem substrato anisotrópico. Inicialmente são consideradas apenas as estruturas com substratos isotrópicos, com diferentes constantes dielétricas, e é avaliada a influência da largura do substrato sobre as freqüências dos modos ressonantes das antenas. Posteriormente, a análise do truncamento do dielétrico é realizada para estruturas com substrato anisotrópico. Em todos os casos, os resultados experimentais, obtidos a partir da construção de protótipos, são confrontados com os obtidos a partir de simulação, utilizando as técnicas TRT e MTRT. No final, as técnicas descritas são utilizadas para antenas tipo patch circular, sendo utilizada uma técnica de equivalência para transformar a antena circular em outra quadrada ou retangular equivalente, dependendo do modo que se queira encontrar. Os resultados obtidos são então analisados, observando-se uma boa concordância e indicando a viabilidade do método. Após isso, são apresentadas as conclusões e sugeridos alguns temas para a continuidade deste trabalho

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The usual programs for load flow calculation were in general developped aiming the simulation of electric energy transmission, subtransmission and distribution systems. However, the mathematical methods and algorithms used by the formulations were based, in majority, just on the characteristics of the transmittion systems, which were the main concern focus of engineers and researchers. Though, the physical characteristics of these systems are quite different from the distribution ones. In the transmission systems, the voltage levels are high and the lines are generally very long. These aspects contribute the capacitive and inductive effects that appear in the system to have a considerable influence in the values of the interest quantities, reason why they should be taken into consideration. Still in the transmission systems, the loads have a macro nature, as for example, cities, neiborhoods, or big industries. These loads are, generally, practically balanced, what reduces the necessity of utilization of three-phase methodology for the load flow calculation. Distribution systems, on the other hand, present different characteristics: the voltage levels are small in comparison to the transmission ones. This almost annul the capacitive effects of the lines. The loads are, in this case, transformers, in whose secondaries are connected small consumers, in a sort of times, mono-phase ones, so that the probability of finding an unbalanced circuit is high. This way, the utilization of three-phase methodologies assumes an important dimension. Besides, equipments like voltage regulators, that use simultaneously the concepts of phase and line voltage in their functioning, need a three-phase methodology, in order to allow the simulation of their real behavior. For the exposed reasons, initially was developped, in the scope of this work, a method for three-phase load flow calculation in order to simulate the steady-state behaviour of distribution systems. Aiming to achieve this goal, the Power Summation Algorithm was used, as a base for developping the three phase method. This algorithm was already widely tested and approved by researchers and engineers in the simulation of radial electric energy distribution systems, mainly for single-phase representation. By our formulation, lines are modeled in three-phase circuits, considering the magnetic coupling between the phases; but the earth effect is considered through the Carson reduction. Its important to point out that, in spite of the loads being normally connected to the transformers secondaries, was considered the hypothesis of existence of star or delta loads connected to the primary circuit. To perform the simulation of voltage regulators, a new model was utilized, allowing the simulation of various types of configurations, according to their real functioning. Finally, was considered the possibility of representation of switches with current measuring in various points of the feeder. The loads are adjusted during the iteractive process, in order to match the current in each switch, converging to the measured value specified by the input data. In a second stage of the work, sensibility parameters were derived taking as base the described load flow, with the objective of suporting further optimization processes. This parameters are found by calculating of the partial derivatives of a variable in respect to another, in general, voltages, losses and reactive powers. After describing the calculation of the sensibility parameters, the Gradient Method was presented, using these parameters to optimize an objective function, that will be defined for each type of study. The first one refers to the reduction of technical losses in a medium voltage feeder, through the installation of capacitor banks; the second one refers to the problem of correction of voltage profile, through the instalation of capacitor banks or voltage regulators. In case of the losses reduction will be considered, as objective function, the sum of the losses in all the parts of the system. To the correction of the voltage profile, the objective function will be the sum of the square voltage deviations in each node, in respect to the rated voltage. In the end of the work, results of application of the described methods in some feeders are presented, aiming to give insight about their performance and acuity

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior