Análise do desempenho de um refrigerador doméstico funcionando com uma válvula de expansão micrométrica

Household refrigerators are equipments that represent a significant portion on the eletricity consumption of Brazilian homes. The use of these devices with low energy efficiency contributes to increase the energy consumption. The energy efficiency of a refrigerator is a function of the interaction between the coolant fluid and the components of the thermodynamic cycle. Changes in load and/or nature of the coolant may modify the condensing and/or evaporation pressures. The volumetric capacity of the compressor, the mass flow of coolant and the compression power are dependent parameters of the condensation and evaporation pressures. Thus, the expansion devices exert an importante role in the balance of these pressures, being fundamental for the better performance of the refrigeration cycle. This experimental research aims to investigate the sensitivity of the performance parameters of a household refrigerator operating with R134a and at different evaporation pressures. Therefore, a small refrigerator was instrumented with temperature, pressure sensors and other variables of interest, installed along the cooling circuit, in order to allow the thermal mapping and the evaluation of the equipment performance parameters. The variation of pressure loss in the coolant fluid resulting from the operation of the expansion valve with micrometric adjustment that modifies the evaporation temperature, influencing significantly the performance parameters of the thermodynamic refrigeration cycle.

Uma modelagem de indicadores de desempenho para instituições de ensino superior no Brasil na abordagem do balanced scorecard: um estudo com instituições privadas

This Master of Science Thesis deals with a BSC modeling for higher education institution focusing on private institution in the Brazilian context. It‟s accomplished a literature review in order to understand the BSC and its application to for profit and non for profit organizations and as a main result it is proposed a BSC conceptual model with a new perspective (Government) and a change in the hierarchy of the main BSC perspective equaling financial to customer/society. Taking the national higher education assessment system of Education Ministry indicators a model is deployed and the relations between the indicators are measured with the Pearson correlation coefficient. As a result a model emerges with sound relations of indicators but a improvement in the financial indicators is needed

Análise de desempenho de um refrigerador de pequeno porte com drop in de refrigerantes hidrocarbonetos

From what was stated in the Montreal Protocol, the researchers and refrigeration industry seek substitutes for synthetic refrigerants -chlorofluorocarbons (CFCs) and HCFCs (HCFC) - that contribute to the depletion of the ozone layer. The phase-out of these substances was started using as one of the replacement alternatives the synthetic fluids based on hydro fluorocarbons (HFCs) that have zero potential depletion of the ozone layer. However, contribute to the process of global warming. HFC refrigerants are greenhouse gases and are part of the group of gases whose emissions must be reduced as the Kyoto Protocol says. The hydrocarbons (HC's), for not contribute to the depletion of the ozone layer, because they have very low global warming potential, and are found abundantly in nature, has been presented as an alternative, and therefore, are being used in new home refrigeration equipment in several countries. In Brazil, due to incipient production of domestic refrigerators using HC's, the transition refrigerants remain on the scene for some years. This dissertation deals with an experimental evaluation of the conduct of a drinking fountain designed to work with HFC (R-134a), operating with a mixture of HC's or isobutane (R-600a) without any modification to the system or the lubricating oil. In the refrigeration laboratory of Federal University of Rio Grande do Norte were installed, in a drinking fountain, temperature and pressure sensors at strategic points in the refrigeration cycle, connected to an acquisition system of computerized data, to enable the mapping and thermodynamics analysis of the device operating with R-134a or with a mixture of HC's or with R-600a. The refrigerator-test operating with the natural fluids (mixture of HC's or R-600a) had a coefficient of performance (COP) lower than the R-134a

Desempenho de analistas sell-side no mercado de ações brasileiro

The purpose of this study was to analyze the behavior of Sell-Side analysts and analysts propose a classification, considering the performance of the price forecasts and recom- mendations (sell-hold-buy) in the Brazilian stock market. For this, the first step was to analyze the consensus of analysts to understand the importance of this collective interven- tion in the market; the second was to analyze the analysts individually to understand how improve their analysis in time. Third was to understand how are the main methods of ranking used in markets. Finally, propose a form of classification that reflects the previous aspects discussed. To investigate the hypotheses proposed in the study were used linear models for panel to capture elements in time. The data of price forecasts and analyst recommendations individually and consensus, in the period 2005-2013 were obtained from Bloomberg R ○ . The main results were: (i) superior performance of consensus recommen- dations, compared with the individual analyzes; (ii) associating the number of analysts issuing recommendations with improved accuracy allows supposing that this number may be associated with increased consensus strength and hence accuracy; (iii) the anchoring effect of the analysts consensus revisions makes his predictions are biased, overvaluating the assets; (iv) analysts need to have greater caution in times of economic turbulence, noting also foreign markets such as the USA. For these may result changes in bias between optimism and pessimism; (v) effects due to changes in bias, as increased pessimism can cause excessive increase in purchase recommendations number. In this case, analysts can should be more cautious in analysis, mainly for consistency between recommendation and the expected price; (vi) the experience of the analyst with the asset economic sector and the asset contributes to the improvement of forecasts, however, the overall experience showed opposite evidence; (vii) the optimism associated with the overall experience, over time, shows a similar behavior to an excess of confidence, which could cause reduction of accuracy; (viii) the conflicting effect of general experience between the accuracy and the observed return shows evidence that, over time, the analyst has effects similar to the endowment bias on assets, which would result in a conflict analysis of recommendations and forecasts ; (ix) despite the focus on fewer sectors contribute to the quality of accuracy, the same does not occur with the focus on assets. So it is possible that analysts may have economies of scale when cover more assets within the same industry; and finally, (x) was possible to develop a proposal for classification analysts to consider both returns and the consistency of these predictions, called Analysis coefficient. This ranking resulted better results, considering the return / standard deviation.

Recomendações para o desenvolvimento de uma ferramenta de suporte às primeiras decisões projetuais visando ao desempenho energético de edificações de escritório em clima quente

PEDRINI, Aldomar; SZOKOLAY, Steven. Recomendações para o desenvolvimento de uma ferramenta de suporte às primeiras decisões projetuais visando ao desempenho energético de edificações de escritório em clima quente. Ambiente Construído, Porto Alegre, v. 5, n. 1, p.39-54, jan./mar. 2005. Trimestral. Disponível em: . Acesso em: 04 out. 2010.

Análise de desempenho sobre redes IEEE 802.3/PM-AH: protoclo multicilos para automação hospitalar

Com a incorporação de conceitos da automação em ambientes hospitalares surge uma série de novos requisitos pertinentes a área médica. Dentre esses requisitos, um que merece destaque é a necessidade do estabelecimento de uma rede de comunicação segura e eficiente entre os elementos do ambiente hospitalar, visto que, os mesmos encontram-se de maneira distribuída. Nesse sentido, existe uma série de protocolos que podem ser utilizados no estabelecimento dessa rede, dentre os quais, um que merece destaque é o PM-AH (Protocolo Multiciclos para Automação Hospitalar) justamente por ser voltado a automatização de ambientes hospitalares tanto no que diz respeito ao cumprimento dos requisitos impostos nesse tipo de ambiente, como pelo fato de ser projetado para funcionar sobre a tecnologia Ethernet, padrão esse que é comumente utilizado pela rede de dados dos hospitais. Em decorrência disso, o presente trabalho aborda uma análise de desempenho comparativa entre redes PM-AH e puramente Ethernet visando atestar a eficiência do primeiro no que diz respeito ao cumprimento dos requisitos impostos pela automação hospitalar

A confiança interorganizacional nas compras

This research is part of the field of organizational studies, focusing on organizational purchase behavior and, specifically, trust interorganizational at the purchases. This topic is current and relevant by addressing the development of good relations between buyer-supplier that increases the exchange of information, increases the length of relationship, reduces the hierarchical controls and improves performance. Furthermore, although there is a vast literature on trust, the scientific work that deal specifically at the trust interorganizational still need further research to synthesize and validate the variables that generate this phenomenon. In this sense, this investigation is to explain the antecedents of trust interorganizational by the relationship between the variable operational performance, organizational characteristics, shared values and interpersonal relationships on purchases by manufacturing industries, in order to develop a robust literature, most consensual, that includes the current sociological and economic, considering the effect of interpersonal relationships in this phenomenon. This proposal is configured in a new vision of the antecedents of interorganizational trust, described as significant quantitative from models Morgan and Hunt (1994), Doney and Cannon (1997), Zhao and Cavusgil (2006) and Nyaga, Whipple, Lynch (2011), as well as qualitative analysis of Tacconi et al. (2011). With regard to methodological aspects, the study assumes the form of a descriptive, survey type, and causal trace theoretical and empirical. As for his nature, the investigation, explicative character, has developed a quantitative approach with the use of exploratory factor analysis and structural equation modeling SEM, with the use of IBM software SPSS Amos 18.0, using the method of maximum verisimilitude, and supported by technical bootstraping. The unit of analysis was the buyer-supplier relationship, in which the object under investigation was the supplier organization in view of the purchasing company. 237 valid questionnaires were collected among key informants, using a simple random sampling developed in manufacturing industries (SIC 10-33), located in the city of Natal and in the region of Natal. The first results of descriptive analysis demonstrate the phenomenon of interorganizational trust, in which purchasing firms believe, feel secure about the supplier. This demonstration showed high levels of intensity, predominantly among the vendors that supply the company with materials that are used directly in the production process. The exploratory and confirmatory factor analysis, performed on each variable alone, generated a set of observable and unobservable variables more consistent, giving rise to a model, that needed to be further specified. This again specify model consists of trajectories was positive, with a good fit, with a composite reliability and variance extracted satisfactory, and demonstrates convergent and discriminant validity, in which the factor loadings are significant and strong explanatory power. Given the findings that reinforce the model again specify data, suggesting a high probability that this model may be more suited for the study population, the results support the explanation that interorganizational trust depends on purchases directly from interpersonal relationships, sharing value and operating performance and indirectly of personal relationships, social networks, organizational characteristics, physical and relational aspect of performance. It is concluded that this trust can be explained by a set of interactions between these three determinants, where the focus is on interpersonal relationships, with the largest path coefficient for the factor under study

Recursos intangíveis de um destino turístico: um estudo de desempenho da cidade de Natal tendo como base a teoria das capacidades dinâmicas

O objetivo desta tese foi analisar os recursos intangíveis de um destino turístico. Foi feito um estudo de desempenho da cidade de Natal tendo como base a teoria das capacidades dinâmicas. Inicialmente, foi desenvolvido um instrumento de pesquisa para oportunizar a construção de um modelo de medida com vistas à captação de variáveis latentes para os recursos intangíveis existentes no setor do turismo em Natal-RN. Em seguida, foi realizada uma análise dos recursos intangíveis que são evidenciados pelos turistas acerca da cidade. Finalmente, foi feita a investigação de um modelo de estrutura que estabeleceu as relações entre as variáveis latentes dos recursos intangíveis e a percepção de desempenho do turismo na cidade de Natal. Procedeu-se uma revisão de literatura para construção de um modelo inicial acerca dos ativos intangíveis dentro da teoria das capacidades e foram relacionados dez recursos, quais sejam: recursos humanos prestadores de serviços; recursos humanos como gestores; cultura local; conservação do meio ambiente; know-how empresarial; inovação empresarial; tecnologia; marca; preço; e promoção. Estes dez recursos, em conjunto, seriam responsáveis pelo desempenho do destino turístico. Após ser realizada uma análise de equações estruturais, apenas quatro recursos manifestaram relações com o desempenho: marca; cultura; conservação do meio ambiente; e preço. Análisando dos dados, verificou-se que a variável desempenho positivo da cidade na ótica do turista se manifestou fortemente e foi influenciada de forma forte pela cultura local, marca e conservação do meio ambiente em conjunto. O preço foi influenciado pelo desempenho positivo mostrando que o turista sente que o preço pago foi satisfatório diante dos atributos do destino Provavelmente, isso seja um ponto positivo muito forte para o destino turístico de Natal, pois, em termos de recursos intangíveis e de juntos formarem capacidades, eles são inimitáveis, raros e são capazes de se ajustarem às mudanças organizacionais e ambientais, para reconfigurar os ativos e as estruturas de um destino, corroborando, assim, com a teoria das capacidades dinâmicas. Esses recursos da cidade de Natal, como destino turístico, são únicos e provavelmente têm um peso muito maior para o desempenho da cidade do que problemas existentes na localidade. Logo, esses atributos devem ser estimulados a continuar crescendo e se modificando de acordo com as exigências atuais e futuras de consumo

Desempenho internacional de empresas exportadoras: um modelo estrutural baseado em capacidades organizacionais e ambiente

The internationalization as an organizational phenomenon fundamentally strategic had as theoretical contributions some Schools that throughout the decades 60, 70, and 80 developed behavioral and economic approaches in order to explain the process. The behavioral approach deals with the perception of phenomenon as a gradual process from the perspective of the executives behavior (JOHANSON and VAHLNE, 1977; HALLÉN and WIEDERSHEIM - PAUL, 1979; CZINKOTA, 1985). This phenomenon in permanent theoretical and managerial evolution made an opportunity to build this investigation, whose goal is to analyse the impact comes from organizational capabilities and the external environment on the international performance of exporting firms. For both, were used as theoretical basis two types of analysis for the comprehension of international performance: Strategic Management - Industrial Organization and Resource-Based View and International Businesses - Current Economic and Behavioral. It was made a cross-sectional survey-based explanatory research, including 150 exporting companies with operations in the Northeast of Brazil. A conceptual model was made with eight constructs and eight research hypotheses, representative of the effects of external factors on international performance. The data were processed using the Exploratory Factor Analysis and Structural Equation Modeling. The structural equations model was reespecified and estimated through the use of the maximum-likelihood method up to achieve adequated values of indexes of adjustment. As the main theoretical contribution, were identified organizational and physical resources which shows the importance of the management skills development, of the learning capability and capability to establish strategic alliances abroad. That because the knowledge, as the operational point of view as in its strategic application, offers to organization conditions of market positioning which can create opportunities sustainable competitive advantages and which impact the performance of international companies

Fatores críticos de sucesso como antecedentes da aceitação de um sistema de informação em uma universidade federal

In recent decades the public sector comes under pressure in order to improve its performance. The use of Information Technology (IT) has been a tool increasingly used in reaching that goal. Thus, it has become an important issue in public organizations, particularly in institutions of higher education, determine which factors influence the acceptance and use of technology, impacting on the success of its implementation and the desired organizational results. The Technology Acceptance Model - TAM was used as the basis for this study and is based on the constructs perceived usefulness and perceived ease of use. However, when it comes to integrated management systems due to the complexity of its implementation,organizational factors were added to thus seek further explanation of the acceptance of such systems. Thus, added to the model five TAM constructs related to critical success factors in implementing ERP systems, they are: support of top management, communication, training, cooperation, and technological complexity (BUENO and SALMERON, 2008). Based on the foregoing, launches the following research problem: What factors influence the acceptance and use of SIE / module academic at the Federal University of Para, from the users' perception of teachers and technicians? The purpose of this study was to identify the influence of organizational factors, and behavioral antecedents of behavioral intention to use the SIE / module academic UFPA in the perspective of teachers and technical users. This is applied research, exploratory and descriptive, quantitative with the implementation of a survey, and data collection occurred through a structured questionnaire applied to a sample of 229 teachers and 30 technical and administrative staff. Data analysis was carried out through descriptive statistics and structural equation modeling with the technique of partial least squares (PLS). Effected primarily to assess the measurement model, which were verified reliability, convergent and discriminant validity for all indicators and constructs. Then the structural model was analyzed using the bootstrap resampling technique like. In assessing statistical significance, all hypotheses were supported. The coefficient of determination (R ²) was high or average in five of the six endogenous variables, so the model explains 47.3% of the variation in behavioral intention. It is noteworthy that among the antecedents of behavioral intention (BI) analyzed in this study, perceived usefulness is the variable that has a greater effect on behavioral intention, followed by ease of use (PEU) and attitude (AT). Among the organizational aspects (critical success factors) studied technological complexity (TC) and training (ERT) were those with greatest effect on behavioral intention to use, although these effects were lower than those produced by behavioral factors (originating from TAM). It is pointed out further that the support of senior management (TMS) showed, among all variables, the least effect on the intention to use (BI) and was followed by communications (COM) and cooperation (CO), which exert a low effect on behavioral intention (BI). Therefore, as other studies on the TAM constructs were adequate for the present research. Thus, the study contributed towards proving evidence that the Technology Acceptance Model can be applied to predict the acceptance of integrated management systems, even in public. Keywords: Technology

Relações entre mecanismos de coordenação e controle com desempenho organizacional: um estudo nas instituições públicas de ensino médio de Natal

This research aimed at relating coordination and control forms to organizational performance. The multicase study was applied in two public high schools: Centro Federal de Educação Tecnológica do Rio Grande do Norte and Floriano Cavalcanti. In order to accomplish these objectives, it was developed a qualitative analysis and considered coordination and control forms of several authors. Also was considered Sander´s (1984) model of organizational performance. The mentioned model considers two criteria to analyze organizational performance: one instrumental (efficiency and efficacy) and other substantive (effectiveness e relevance). The research attempts to show the importance of balancing these criteria in a way that effectiveness and relevance becomes more important at schools. It was proven that the use of bureaucratic coordination forms has the power to influence the evaluation on the instrumental technique. At the same time, it was observed that the use of mechanisms based on the autonomy of the school is related to efficiency and efficacy. The object of this research can be considered successful

Atuação e desempenho do Ministério Público do Estado do Rio Grande do Norte no contexto da gestão pública: perspectiva estratégica

The present dissertation analyzes the performance and acting of the Rio Grande do Norte Public Ministery, in the strategic perspective, while responsible Institution for the defense of the collective rights. The comprehension of this theme inserts in a context of modernization of the public administration, in which is inserted, as well as their functional and structural changes, in a reality of innovations there is passing the organizations, looking to rescue the legitimacy of the government organizations, aligning them to the democratic values of the society. It detaches the strategic administration and the public administration and it exposes the strategic performance about the central point of the study, focusing in the development of the organization in the last four years, and other relative subjects to the acting. It is a unic case study, framed in the characteristics of the qualitative approaches - descriptive and exploratory. The analysis showed, through the method of content analysis, by the criterion of thematic categorization, that MP / RN come developing in an intense way,and it detaches that the changes already happened reflect a good strategic acting of the Institution, especially in the structural and functional areas, showing the strategic conscience of this, although that is not still enough to consider it as a strategic organization, and it concludes that there is still a lot for doing, and that the occurrence of an administration typically strategic in the extent of MP/RN is possible, with the conscience and participation of all, members and servants

Eleição nas escolas: uma análise do impacto do diretor eleito sobre o desempenho educacional no Estado da Bahia

In Brazil, the selection of school principals is set in a decentralized manner by each state and city, such that processes may vary with time for a specific locality. In the state of Bahia, school principals were appointed by a higher political hierarchy until 2008, when schools under state administration started selecting principals by elections. The main goal of this work is to evaluate whether changing this specific rule affected students proficiency levels. This is achieved by using a panel data and difference-in-differences approachs that compares state schools (treatment group) to city schools (control group) that did not face a selection rule change and thus kept having their principals politically appointed. The databases used are Prova Brasil 2007, 2009 and 2011, the first one prior and the other two former to the policy change. Our results suggest that students attending schools with principals that are selected and elected have slightly lower mean proficiency levels both in mathematics and in portuguese exams than those attending schools with appointed principals. This result, according to the literature, could be related to perverse effects of selecting school administrators by vote, such as corporatism, clientelism and politicization of the school environment

Desempenho e background familiar: um estudo no acesso a uma instituição de ensino técnico federal no Brasil

This paper comprises an investigation on the influence of the variable family backgrounds (father school level, mother school level and family income) over the pupil s performance in admissions examination (entrance test or PROITEC) at Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte (IFRN). From that point of view, the main goal of this research is to analyze the influence of the family background as a determiner of the pupil´s performance in the access to Technical and Professional education at IFRN. Secondary data were used from two databases (entrance test and PROITEC) adding up to 19.226 observations to the vacancies offered in the year of 2013. Aiming at achieving the proposed goal, a conceptual model composed of three hypothesis was developed. The results were presented in four stages: stage I presentation of the descriptive statistical results of the two databases; stage II separation of the campi in clusters; stage III analysis of multiple regressions; stage IV analysis of the logistics regressions. Two statistical tests were used to validate the hypothesis: T-test and Wald test. Hypothesis 1 and 2 were confirmed and H3 was refused. The results presented favorable causal connections to the family income and the father school level variables (with bigger effect for fathers with a higher education degree). The mother school level variable did not provide statistical significance for this research. Based on this result, after this work, this institution is to develop a strategic plan to assist in the success rate of students preparing diagnoses in order to diminish the effects of the variables that impacted negatively

Proposta de método para avaliação do desempenho térmico de residências unifamiliares em clima quente e úmido

Nowadays, evaluation methods to measure thermal performance of buildings have been developed in order to improve thermal comfort in buildings and reduce the use of energy with active cooling and heating systems. However, in developed countries, the criteria used in rating systems to asses the thermal and energy performance of buildings have demonstrated some limitations when applied to naturally ventilated building in tropical climates. The present research has as its main objective to propose a method to evaluate the thermal performance of low-rise residential buildings in warm humid climates, through computational simulation. The method was developed in order to conceive a suitable rating system for the athermal performance assessment of such buildings using as criteria the indoor air temperature and a thermal comfort adaptive model. The research made use of the software VisualDOE 4.1 in two simulations runs of a base case modeled for two basic types of occupancies: living room and bedroom. In the first simulation run, sensitive analyses were made to identify the variables with the higher impact over the cases´ thermal performance. Besides that, the results also allowed the formulation of design recommendations to warm humid climates toward an improvement on the thermal performance of residential building in similar situations. The results of the second simulation run was used to identify the named Thermal Performance Spectrum (TPS) of both occupancies types, which reflect the variations on the thermal performance considering the local climate, building typology, chosen construction material and studied occupancies. This analysis generates an index named IDTR Thermal Performance Resultant Index, which was configured as a thermal performance rating system. It correlates the thermal performance with the number of hours that the indoor air temperature was on each of the six thermal comfort bands pre-defined that received weights to measure the discomfort intensity. The use of this rating system showed to be appropriated when used in one of the simulated cases, presenting advantages in relation to other evaluation methods and becoming a tool for the understanding of building thermal behavior