28 resultados para Refrigeration of system

em Universidade Federal do Rio Grande do Norte(UFRN)


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BRITTO, Ricardo S.; MEDEIROS, Adelardo A. D.; ALSINA, Pablo J. Uma arquitetura distribuída de hardware e software para controle de um robô móvel autônomo. In: SIMPÓSIO BRASILEIRO DE AUTOMAÇÃO INTELIGENTE,8., 2007, Florianópolis. Anais... Florianópolis: SBAI, 2007.

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Oxide type spinel AB2O4 presents structure adjusted for application in the automobile industry. The spinel of cobalt has many practical applications had its excellent physical and chemical properties such as catalyst in hydrocarbon oxidation reaction. The CeO2 has been used in many of these processes because it assigns to a material with excellent thermal resistance and mechanics, high capacity of oxygen stockage (OSC) among others properties. This work deals with the synthesis, characterization and catalytic application of spinel of cobalt and CeO2 with fluorita structure, obtained for method of Pechini and method of Gel-Combustion. The process of Pechini, the puff was obtained at 300 ºC for 2 h in air. In the process of Gel-Combustion the approximately at 350 ºC material was prepared and burnt for Pyrolysis, both had been calcined at 500 ºC, 700 ºC, 900 ºC and 1050 ºC for 2 h in air. The materials of the calcinations had been characterized by TG/DTA, electronic microscopy of sweepings (MEV), spectroscopy of absorption in the infra-red ray (FTIR) and diffraction of X-rays (DRX). The obtained material reaches the phase oxide at 450 oC for Pechini method and 500 °C for combustion method. The samples were submitted catalytic reaction of n-hexane on superficies of materials. The reactor function in molar ration of 0, 85 mol.h-1.g-1 and temperature of system was 450 °C. The sample obtained for Pechini and support in alumine of superficial area of 178,63 m2.g-1 calcined at 700 ºC, give results of catalytic conversions of 39 % and the sample obtained for method of gel-combustion and support in alumina of 150 mesh calcined at 500 ºC result 13 % of conversion. Both method were selective specie C1

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Cells the solid oxide fuel are systems capable to directly convert energy of a chemical reaction into electric energy in clean, quiet way and if its components in the solid state differentiate of excessively the techniques for having all. Its more common geometric configurations are: the tubular one and to glide. Geometry to glide beyond the usual components (anode, cathode and electrolyte) needs interconnect and sealant. E the search for materials adjusted for these components is currently the biggest challenge found for the production of the cells. The sealants need to present chemical stability in high temperatures, to provoke electric isolation, to have coefficient of compatible thermal expansion with the excessively component ones. For presenting these characteristics the glass-ceramics materials are recommended for the application. In this work the study of the partial substitution of the ZrO2 for the Al2O3 in system LZS became it aiming at the formation of system LZAS, this with the addition of natural spodumene with 10, 20 and 30% in mass. The compositions had been casting to a temperature of 1500°C and later quickly cooled with the objective to continue amorphous. Each composition was worn out for attainment of a dust with average diameter of approximately 3μm and characterized by the techniques of DRX, FRX, MEV, dilatometric analysis and particle size analysis. Later the samples had been conformed and treated thermally with temperatures in the interval between 700-1000 °C, with platform of 10 minutes and 1 hour. The analyses for the treated samples had been: dilatometric analysis, DRX, FRX, electrical conductivity and tack. The results point with respect to the viability of the use of system LZAS for use as sealant a time that had presented good results as isolating electric, they had adhered to a material with similar α of the components of a SOFC and had presented steady crystalline phases

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Tuberculosis is a serious disease, but curable in practically 100% of new cases, since complied the principles of modern chemotherapy. Isoniazid (ISN), Rifampicin (RIF), Pyrazinamide (PYR) and Chloride Ethambutol (ETA) are considered first line drugs in the treatment of tuberculosis, by combining the highest level of efficiency with acceptable degree of toxicity. Concerning USP 33 - NF28 (2010) the chromatography analysis to 3 of 4 drugs (ISN, PYR and RIF) last in average 15 minutes and 10 minutes more to obtain the 4th drug (ETA) using a column and mobile phase mixture different, becoming its industrial application unfavorable. Thus, many studies have being carried out to minimize this problem. An alternative would use the UFLC, which is based with the same principles of HPLC, however it uses stationary phases with particles smaller than 2 μm. Therefore, this study goals to develop and validate new analytical methods to determine simultaneously the drugs by HPLC/DAD and UFLC/DAD. For this, a analytical screening was carried out, which verified that is necessary a gradient of mobile phase system A (acetate buffer:methanol 94:6 v/v) and B (acetate buffer:acetonitrile 55:45 v/v). Furthermore, to the development and optimization of the method in HPLC and UFLC, with achievement of the values of system suitability into the criteria limits required for both techniques, the validations have began. Standard solutions and tablets test solutions were prepared and injected into HPLC and UFLC, containing 0.008 mg/mL ISN, 0.043 mg/mL PYR, 0.030 mg.mL-1 ETA and 0.016 mg/mL RIF. The validation of analytical methods for HPLC and UFLC was carried out with the determination of specificity/selectivity, analytical curve, linearity, precision, limits of detection and quantification, accuracy and robustness. The methods were adequate for determination of 4 drugs separately without interfered with the others. Precise, due to the fact of the methods demonstrated since with the days variation, besides the repeatability, the values were into the level required by the regular agency. Linear (R> 0,99), once the methods were capable to demonstrate results directly proportional to the concentration of the analyte sample, within of specified range. Accurate, once the methods were capable to present values of variation coefficient and recovery percentage into the required limits (98 to 102%). The methods showed LOD and LOQ very low showing the high sensitivity of the methods for the four drugs. The robustness of the methods were evaluate, facing the temperature and flow changes, where they showed robustness just with the preview conditions established of temperature and flow, abrupt changes may influence with the results of methods

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We had as the problem of analysis in this research: what are the assumptions, principles and general content that based the Sistema Nacional de Avaliação da Educação Superior (SINAES). We started from the hypothesis that the general content of SINAES is essentially based on the assumptions and principles of a control/regulatory perspective of evaluation and a summative epistemology, objectivist and quantitativist, constituted by members who prioritize testing and classification of courses and institutions based on market values. The overall goal was to make a political evaluation of SINAES and the specific objectives were: a) apply the concepts of politics evaluation and meta-evaluation, b) identify the role of international organizations in education reform in the 1990s and its impact on superior education in Brazil c) redeem the concept of evaluation, especially in the field of studies in education; and d) investigate the evaluation policies of Brazilian superior education leading to SINAES. As for the technical procedures for collecting and analyzing data, the research was made with bibliography and documents, considering that it was developed by bibliographic sources and official publications. It was developed by crossing sources: texts or documents remitted to others; it was also concentrated: on the role of international organizations in educational and State reforms (in the 1990s); on the policies of evaluation of the Brazilian superior education (1980s and 1990s); on the proposal of the Comissão Especial de Avaliação (CEA); on the Law No. 10.861/2004; on the documents of CONAES; on the Decree No. 5.773/2006, and the MEC Regulatory Ordinances No. 4/2008 and No. 12/2008. It did not stop in the so called purely technical aspects, but in the ideological field itself. The research found that international organizations, notably the World Bank, played a political, intellectual and financial role determinant to the field of education, a fact that reflects in the legal framework. It was also found that the politics of evaluation of the superior education is historically marked by conflict, represented by two distinct perspectives of different natures and emphases. On one hand, the focus is on control / regulation, favoring efficiency, productivity and competitiveness benchmarking and prioritizing the punctual performance and measurement. On the other, it seeks to transform academic perspective in primarily formative / emancipatory, in order to support more institutional improvement. It was concluded that the CEA presented a conception evaluation predominantly formative and emancipatory, which emphasized the idea of system, centered around the institution and repudiated the rankings practices. In the post-formulation period, however, some of its principles were fragmenting and, gradually, the institution was giving way to the courses and the Exame Nacional de Desempenho de Estudantes (ENADE) grew in prominence. With the creation of the Conceito Preliminar de Cursos superiores (CPC) and of the Índice Geral de Cursos da Instituição de Educação Superior (IGC), it was redemeed the practice of evaluation as measurement and control, under the principles of efficiency and productivity. So, SINAES that seemed like a progressive evaluation method has assumed a setting that close resembles the Exame Nacional de Cursos (ENC-Provão). Nevertheless, the survival of institutional formative evaluation, in the superior education evaluation policies, still an issue in dispute

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The research arose from the necessity of showing ways to be followed by the actors of the System Guaranteeing Rights of the Child and Adolescent (SGD), regarding the implementation of rights for young people, because the legislation in force in Brazil is currently considered a model around the world and, paradoxically, the fundamental rights of children and adolescents are not met, even with the constitutionally guaranteed priority. Thus, the study investigates the fundamentality rights for young people, enshrined in the Constitution of the Republic, as well as the ways of effectiveness of these rights through the actions of actors of the System Guaranteeing Rights, especially the judiciary. Focusing realized, studying theories of fundamental rights, especially Structuring a Theory of Law (Strukturiende Rechtslehre), Friedrich Müller, who emphasizes the need for analysis of social reality in the application of the rule of law. Study also the public budget and public policies concerning children and adolescents, with emphasis on preparation of budget laws and the process of discussion, deliberation, choice and implementation of public policies for children and teenagers. It then presents the typical functions of the members of System Guaranteeing Rights, as well as prepare a plan for optimum performance for each of the actors, with emphasis on analysis of the implementation of public policies at the municipal level. Finally, it analyzes the theory of separation of three powers, and discusses the positive and negative factors for judicial intervention, concluding that the Courts can consider the action activist, from finding the omission of the Executive and legislative branches, as regards the implementation of the rights of children and adolescents, as well as the rights of children and young people are not realized in most cases, due to the omission of actors of the System Guaranteeing Rights

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The Brazilian tax structure has specific characteristics and the performance level of government. The autonomy given to municipalities to manage their activities after the 1988 Constitution, made them highly dependent on intergovernmental transfers of resources, revealing the fragility of the administrative capacity of these entities. The vertical gap revealed by the constitutional structure of the Brazilian fiscal federalism model contributes to the formation of this specific feature that you are eroding the tax base and the ability of municipal own revenues. Although there was a better regulation of these transfers after the enactment of the Fiscal Responsibility Law, it is observed that the amount of resources transferred to the municipalities of Rio Grande do Norte is very high and is the main source of revenue of municipalities. In light of the theory of federalism and fiscal decentralization, in particular, the theories related to intergovernmental transfers, we seek to diagnose the transfers from the systematization of information on the origin, destination and value. We used the econometric model of System Dynamic Panel GMM in making the diagnosis and verification of the impact of transfers on public finances of the municipalities of the newborn, associated with a review in light of the theory of fiscal federalism and intergovernmental transfers. The paper presents some proposals for the transfer system and the composition of spending in order to contribute to greater tax efficiency

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Although the records indicate the involvement of the City Christmas in the feeding system HiperDia, a survey conducted by the Health Ministry in 2004 found that the number of entries made in Natal was well below estimate. In order to understand the functioning of HiperDia, we performed this study to analyze the actions taken by the professionals involved in power system HiperDia in Natal / RN. The research has developed into a quantitative perspective, with the design of exploratory case study conducted in the health services that integrate the various levels of the organization who are directly involved with the process of system power HiperDia in Natal / RN , represented here by SMS, health districts and the Family Health Units in the period from August to October 2008.Study participants were 110 professionals, including nurses, physicians, operators, administrator and a coordinator. The survey results showed that feeding HiperDia in Natal was maintained mainly by health professionals and operators. Activities include carrying out the state registration, monitoring, and updating of data transfer routines. They report that the difficulties in the process of feeding data are related to the work of teams and / or lack of structure of the Program of Hypertension and Diabetes (HA and DM), the discontinuity of federal investments in improving the HiperDia and lack of training. We can see then that the process of feeding system on Christmas HiperDia therefore is developing the three levels (SMS, districts and health units), however is not matching the expectations established by MS, considering that the gaps the flow of information are undermining the end result of this process

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One of the concerns of this century is with the handling and the final destination of urban solid waste (RSU), where depending on the form as they will be made use, they can cause diverse problems, they are of ambient or social order, being able to generate the loss of the quality of life and illnesses to the population, of direct or indirect form. The objective of the present work was to diagnosis the environmental partner situation of the Final Destination of the urban solid residues in the District of Guajiru, city of São Gonçalo do Amarante/RN, standing out the partner-economic situation of the scavengers. The research was carried through in the period of March of 2008 the October of 2009, with a methodology developed through analyzes them of documents made available for the state ambient agency, the Air base of Christmas and managing agencies of the city. For collection of the date, it was used directly application of the questionnaire with 20 existing scavengers in points of destination of residues, evaluation of the old place of final destination through the use of the spread sheet of the IQR (Index of Quality of the Residues), developed for the CETESB, identification of the matter dump and photographic register. For effect of treatment of the data, a descriptive analysis with regard to the answers of the interviewed scavengers was carried through. The acquired date, Scale had been according to tabulated and analyzed in Excel 2003, where they had been generated graphical to observe the behavior of the data. The results show that of the twenty interviewed scavengers, 35% possess age between 20 and 30 years; 75% possess incomplete basic education; 60% inhabit in houses of waal or huts (cardboard or wood); 55% do not make use of system of water supply and system of sanitary exhaustion; with regard to income monthly for scavengers, 35% had presented income between R$ 200,00 and R$300,00 and 20% possess income above of R$ 500,00 for possessing another source of income; 80% of the interviewed ones, use some type of equipment of individual protection; In the year of 2009, confirming what it was informed by the State agency of Environment, during the field visit, we evidence that the city of Is Gonçalo do Amarante, currently, destines its residues in Sanitary landfill of São Region Metropolitan of Natal in the District of Massaranduba in the city of Ceará-Mirim, after some interventions of the State Public prosecution service. However, in the district of Guajiru some diggings still exist that today are used as final destination of RCD' s (Residues of Construction and Demolition) of the cities of Natal and São Gonçalo do Amarante, as well as private dumps that are used by scavengers that deviate the final destination (Sanitary landfill) of the residues of the great generators (supermarkets, shopping Center and hotels), with presence of urubus, generating a new ambient problem for the city and the aeroportuária security. Ahead of this scene, the study it suggests viable alternatives for the elimination of the private dumps and for the social situation of the escavengers, aiming at to improve its quality of life and 10 to minimize the ambient impacts caused by the inadequate destination of the solid waste in the community of Guajiru, São Gonçalo do Amarante/RN, being able to contribute so that the public managers carry through action in the handling and the control of the final destination of the urban solid waste

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Due of industrial informatics several attempts have been done to develop notations and semantics, which are used for classifying and describing different kind of system behavior, particularly in the modeling phase. Such attempts provide the infrastructure to resolve some real problems of engineering and construct practical systems that aim at, mainly, to increase the productivity, quality, and security of the process. Despite the many studies that have attempted to develop friendly methods for industrial controller programming, they are still programmed by conventional trial-and-error methods and, in practice, there is little written documentation on these systems. The ideal solution would be to use a computational environment that allows industrial engineers to implement the system using high-level language and that follows international standards. Accordingly, this work proposes a methodology for plant and control modelling of the discrete event systems that include sequential, parallel and timed operations, using a formalism based on Statecharts, denominated Basic Statechart (BSC). The methodology also permits automatic procedures to validate and implement these systems. To validate our methodology, we presented two case studies with typical examples of the manufacturing sector. The first example shows a sequential control for a tagged machine, which is used to illustrated dependences between the devices of the plant. In the second example, we discuss more than one strategy for controlling a manufacturing cell. The model with no control has 72 states (distinct configurations) and, the model with sequential control generated 20 different states, but they only act in 8 distinct configurations. The model with parallel control generated 210 different states, but these 210 configurations act only in 26 distinct configurations, therefore, one strategy control less restrictive than previous. Lastly, we presented one example for highlight the modular characteristic of our methodology, which it is very important to maintenance of applications. In this example, the sensors for identifying pieces in the plant were removed. So, changes in the control model are needed to transmit the information of the input buffer sensor to the others positions of the cell

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Conventional control strategies used in shunt active power filters (SAPF) employs real-time instantaneous harmonic detection schemes which is usually implements with digital filters. This increase the number of current sensors on the filter structure which results in high costs. Furthermore, these detection schemes introduce time delays which can deteriorate the harmonic compensation performance. Differently from the conventional control schemes, this paper proposes a non-standard control strategy which indirectly regulates the phase currents of the power mains. The reference currents of system are generated by the dc-link voltage controller and is based on the active power balance of SAPF system. The reference currents are aligned to the phase angle of the power mains voltage vector which is obtained by using a dq phase locked loop (PLL) system. The current control strategy is implemented by an adaptive pole placement control strategy integrated to a variable structure control scheme (VS-APPC). In the VS-APPC, the internal model principle (IMP) of reference currents is used for achieving the zero steady state tracking error of the power system currents. This forces the phase current of the system mains to be sinusoidal with low harmonics content. Moreover, the current controllers are implemented on the stationary reference frame to avoid transformations to the mains voltage vector reference coordinates. This proposed current control strategy enhance the performance of SAPF with fast transient response and robustness to parametric uncertainties. Experimental results are showing for determining the effectiveness of SAPF proposed control system

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In this work, we present a hardware-software architecture for controlling the autonomous mobile robot Kapeck. The hardware of the robot is composed of a set of sensors and actuators organized in a CAN bus. Two embedded computers and eigth microcontroller based boards are used in the system. One of the computers hosts the vision system, due to the significant processing needs of this kind of system. The other computer is used to coordinate and access the CAN bus and to accomplish the other activities of the robot. The microcontroller-based boards are used with the sensors and actuators. The robot has this distributed configuration in order to exhibit a good real-time behavior, where the response time and the temporal predictability of the system is important. We adopted the hybrid deliberative-reactive paradigm in the proposed architecture to conciliate the reactive behavior of the sensors-actuators net and the deliberative activities required to accomplish more complex tasks

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At present, the electricity generation through wind energy has an importance growing in the world, with the existence of very large plans for future wind power installation worldwide. Thus, the increasing the electricity generation through wind power requires, more and more, analysis of studies of interaction between wind parks and electric power systems. This paper has as purposes to implement equivalent models for synchronous wind generators to represent a wind park in ATP program and to check behavior of the models through simulations. Simulations with applications of faults were achieved to evaluate the behavior of voltages of system for each equivalent model, through comparisons between the results of models proposed, to verify if the differences obtained allows the adoption of the simplest model

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The industries are getting more and more rigorous, when security is in question, no matter is to avoid financial damages due to accidents and low productivity, or when it s related to the environment protection. It was thinking about great world accidents around the world involving aircrafts and industrial process (nuclear, petrochemical and so on) that we decided to invest in systems that could detect fault and diagnosis (FDD) them. The FDD systems can avoid eventual fault helping man on the maintenance and exchange of defective equipments. Nowadays, the issues that involve detection, isolation, diagnose and the controlling of tolerance fault are gathering strength in the academic and industrial environment. It is based on this fact, in this work, we discuss the importance of techniques that can assist in the development of systems for Fault Detection and Diagnosis (FDD) and propose a hybrid method for FDD in dynamic systems. We present a brief history to contextualize the techniques used in working environments. The detection of fault in the proposed system is based on state observers in conjunction with other statistical techniques. The principal idea is to use the observer himself, in addition to serving as an analytical redundancy, in allowing the creation of a residue. This residue is used in FDD. A signature database assists in the identification of system faults, which based on the signatures derived from trend analysis of the residue signal and its difference, performs the classification of the faults based purely on a decision tree. This FDD system is tested and validated in two plants: a simulated plant with coupled tanks and didactic plant with industrial instrumentation. All collected results of those tests will be discussed

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Conventional control strategies used in shunt active power filters (SAPF) employs real-time instantaneous harmonic detection schemes which is usually implements with digital filters. This increase the number of current sensors on the filter structure which results in high costs. Furthermore, these detection schemes introduce time delays which can deteriorate the harmonic compensation performance. Differently from the conventional control schemes, this paper proposes a non-standard control strategy which indirectly regulates the phase currents of the power mains. The reference currents of system are generated by the dc-link voltage controller and is based on the active power balance of SAPF system. The reference currents are aligned to the phase angle of the power mains voltage vector which is obtained by using a dq phase locked loop (PLL) system. The current control strategy is implemented by an adaptive pole placement control strategy integrated to a variable structure control scheme (VS¡APPC). In the VS¡APPC, the internal model principle (IMP) of reference currents is used for achieving the zero steady state tracking error of the power system currents. This forces the phase current of the system mains to be sinusoidal with low harmonics content. Moreover, the current controllers are implemented on the stationary reference frame to avoid transformations to the mains voltage vector reference coordinates. This proposed current control strategy enhance the performance of SAPF with fast transient response and robustness to parametric uncertainties. Experimental results are showing for determining the effectiveness of SAPF proposed control system