Propriedades Físicas do Semicondutor Bi2Te3

Thermoelectric Refrigerators (TEC Thermoelectric Cooling) are solid-state heat pumps used in applications where stabilization of temperature cycles or cooling below the room temperature are required. TEC are based on thermoelectric devices, and these in turn, are based on the Peltier effect, which is the production of a difference in temperature when an electric current is applied to a junction formed by two non-similar materials. This is one of the three thermoelectric effects and is a typical semiconductor junction phenomenon. The thermoelectric efficiency, known as Z thermoelectric or merit figure is a parameter that measures the quality of a thermoelectric device. It depends directly on electrical conductivity and inversely on the thermal conductivity. Therefore, good thermoelectric devices have typically high values of electrical conductivity and low values of thermal conductivity. One of the most common materials in the composition of thermoelectric devices is the semiconductor bismuth telluride (Bi2Te3) and its alloys. Peltier plates made up by crystals of semiconductor P-type and N-type are commercially available for various applications in thermoelectric systems. In this work, we characterize the electrical properties of bismuth telluride through conductivity/resistivity of the material, and X-rays power diffraction and magnetoresistance measurements. The results were compared with values taken from specific literature. Moreover, two techniques of material preparation, and applications in refrigerators, are discussed

Avaliação de implementação da Educação Superior a Distância: o caso da Secretaria de Educação a Distância da Universidade Federal do Rio Grande do Norte SEDIS/UFRN

The considerable expansion of Distance Education registered in recent years in Brazil raises the importance of debate about how the implementation of this policy has been happening so that formulators and implementers make better informed decisions, maximizing results, identifying successes and overcoming bottlenecks. This study aims to evaluate the implementation process of Distance Education policy by Secretary of Distance Education of the Federal University of Rio Grande do Norte. For this, we sought to use an evaluation proposal consistent with this policy, and came to the one developed by Sonia Draibe (2001), which suggests an analysis called anatomy of evaluation general process. To achieve the objectives, we made a qualitative research, case study type, using documentary research and semi-structured interviews with three groups of subjects who belong to the policy: managers, technicians and beneficiaries. It was concluded that: the implementation process needs a open contact channel between the management and technicians and beneficiaries; the lack of clarity in the dissemination of information between technicians produces noises that affects the outcomes; the absence of dissemination of internal and external actions contributes to the perpetuation of prejudice in relation to Distance Education; using selection criteria based on competence and merit contributes to form a team of skilled technicians to perform their function within the policy; an institution that do not enable technicians generates gaps that possibly will turn into policy implementation failures; all subjects involved in politics need internal evaluations to contribute to improvements in the implementation process, however, a gap is opened between the subjects if there is no socialization of results; the existence of an internal structure that manipulates financial resources and balances the budget from different maintainer programs is essencial; the consortium between IES and municipalities in presential support poles are bottlenecks in the process, since beneficiaries are exposed to inconsistency and lack of commitment of these local municipalities

Refrigerator COP with thermal storage

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Stratified Sampling Applied to Estimation of the Volumetric Fraction of Alumina in Cast Metal Matrix Composites

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Photopyroelectric response of PTCa/PEEK composite

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Postoperative renal function evaluation, through RIFLE criteria, of elderly patients who underwent femur fracture surgery under spinal anesthesia

Introduction. The postoperative acute renal failure (ARF) incidence in different kinds of surgery has rarely been studied. Age, cardiac dysfunction, previous renal dysfunction, intraoperative hypoperfusion, and use of nephrotoxic medications are mentioned as risk factors for ARF at the postoperative period. The postoperative ARF definition was based on the creatinine increase by the RIFLE classification (R = risk, I = injury, F = failure, L = loss, E = end stage), which corresponds to a 1.5 creatinine increase, two to three times, respectively, above the basal value. This study aimed to evaluate the postoperative ARF incidence in elderly patients who underwent femur fracture surgery under subarachnoid anesthesia and stratify it by the RIFLE criteria. Methods. Ninety patients older than 65 years under spinal anesthesia with fixed dosage of 15 mg of 0.5% isobaric bupivacaine associated with morphine 50 g were studied. Immediate postoperative creatinine was considered basal and compared with maximal creatinine evaluated at 24, 48, and 72 postoperative hours. Results. The mean age of the patients was 80.27 years. ARF incidence was 24.44% and stratified this way: R = 21.11% and I = 3.33%. Conclusions. In conclusion, the postoperative ARF incidence after femur fracture surgery in patients over 65 years was 24.44%. By analyzing the stratification based on the RIFLE classification, the incidence was categorized as Risk (R) = 21.11% and Injury (I) = 3.33%.

Estudo comparativo entre protocolos para profilaxia da trombose venosa profunda: uma nova proposta

INTRODUÇÃO: O artigo compara os protocolos Davison-Caprini (americano) e Sandri (brasileiro) para profilaxia da trombose venosa profunda (TVP), buscando a elaboração de um novo protocolo, mais abrangente e aplicável. MÉTODO: Foi realizado um estudo prospectivo, durante um ano, abrangendo 212 pacientes, comparando os protocolos quanto à estratificação de risco de TVP, e ao tipo de profilaxia indicado. Um novo protocolo foi proposto, aplicado e comparado aos anteriores. RESULTADOS: Obteve-se um novo protocolo, denominado Sandri modificado, que restringe a heparina a um grupo seleto de pacientes, semelhante ao americano, mantendo-se adequado tanto para cirurgias estéticas quanto reparadoras. CONCLUSÕES: A baixa adesão, por parte dos cirurgiões plásticos, ao uso rotineiro da profilaxia de TVP, espelha a escassez de informação sobre o tema. O protocolo Sandri modificado busca melhorar a compreensão e a aplicabilidade da profilaxia da TVP na cirurgia plástica.

Caracterização hidrodinâmica e morfo-sedimentar do estuário Potengi e áreas adjascentes: subsídios para controle e recuperação ambiental no caso de derrames de hidrocarboneto

This study presents the Environmental Sensibility Mapping to oil spillings on the Potengi estuary - RN and neighboring coastline through remote sensing data, collecting, treatment and integration of the geomorphologic, oceanographic (temperature, salinity, density, direction and intensity), meteorological (wind speed and direction) and high resolution seismic (bathymetry and sonography) data. The Potengi river estuary is located on the eastern coastline of the Rio Grande do Norte State, being inserted in the geological context for the coastal Pernambuco-Paraíba basin and spreading over 18 km; it shelters the Natal harbor zone and an oil terminal, centralizing, therefore, important oil transport operations that can cause accidental spillings. Under the oceanographic point of view, the Potengi estuary is characterized by the absence of any expressive thermic stratification, being classified as partially mixed, B type according to Pritchard (1955), and 2 type in conformity to the stratification-circulation diagram by Hansen & Rattray (1966). Two main wind systems are responsable for the formation of wave sets that occur in the area. The dynamic tide presents, in the Natal Harbor, mean amplitude in spring and quadrature tides, with around 2.8 and 2m, respectively. The mechanism of saline tide mixing was defined through the salinity which is the main parameter for the identification of this mechanism. Important variations of the salinity mean values (36.32 psu), temperature (28.11ºC) and density (22.96 kg/m3) in the estuarine waters presented features belonging to low latitude regions. The water temperature follows the air temperature variations, in the region, with expressive daily amplitudes. In this study, the identification of the estuarine bed morphology through bathymetric and sonographic analysis, had the purpose to evaluate the influence of the superficial and bottom currents for the bottom shaping. In this way, the use of the side scan sonar showed, to be very useful in the identification of the bottom morphology and its relationship with the predominant action of the tidal currents in the Potengi estuary. Besides, it showed how the sonograms can be a support to the comparison of the several patterns derived from the local hydrodynamic variations. The holocene sediments, which fill the estuarine channel, are predominantly sandy, varying from selected, sometimes silty. The sedimentation is controlled by the environmental hydrodynamic conditions, being recognized two important textural facies: Muddy Facies and Sandy Facies. The distribution of these textural facies apparently oscillates owing to the tidal cycle and flow intensity. Each one of the above mentioned data was integrated in a Geographic Information System (GIS), from which was produced the Environmental Sensibility Map to oil spillings with Coastal Sensibility Index (CSI) to the Potengi estuary. The integrated analysis of these data is essential to oil spilling contingency plans, in order to reduce the spilling environmental consequences and to make efficient the endeavours of contention and cleaning up/removal on the Natal Harbor. This study has the aim to collaborate for the increase of informations about the estuarine environment and contribute to a better management of the question: environment/polluting loads

A produção capitalista do espaço: os loteamentos, os condomínios fechados e o seu papel na formação do Bairro de Nova Parnamirim/Parnamirim-RN

This work exposed desired to investigate the function of evolution of closed allotment, of market of the earth and of forms of extraction of the lace of earth, in the processes capitalist production of urban space in Nova Parnamirim, community of Parnamirim/RN. This tendentious urbanization were marked for an expressive increase of number of horizontal and vertical closed residences joint ownership concerning at social groups more privileged financial position. Go after, set off, a temporal investigation, based in the forms of appropriation of space in the middle intermediate by action of the several producers agent of capitalist capital. This way, make necessary understand the past of local structure earth, in order that to make possible analyze the beginning of the process. Not enough, appealed the publics institutions as immobile notary s office and secretary municipal for to collect the more important information, and in the field through of application of formulary together the population of ward, in order that of examine the motivation of residential establishment inside. Make this, confirmed that the actual spatial organization of ward of Nova Parnamirim started of two allotments: the Vale do Pitimbú Park and Eucaliptos Park, both divided in several little allotments. Before of begin the ward, allotments reproduced set off from that native has been consigned during the 80, 90 decade s and begin the actual century, resigning a complicated urban structure earth, dynamized by exploration of a promising residential area. Leashed of this, confirmed the installation of logic of segregation and auto-segregation conducted by an immobile market which exclude the poor class and absorb rich class, motivate by perspective of obtaining of urban lace of earth by immobile promoter. However, perceived that the growth this market was promoted by migration of groups of capital, interior of state and others regions of country. Not distant, horizontal and vertical closed residences represent production forms of a new form of residence, corresponding the pattern architectonic as socioeconomics, strengthened by ideal of security, quality of life, necessity of reclusion and of proximity of Natal. Is in the capital which this individual found possibilities of attend satisfactory minimum of yours necessity in relation a consumption of bens and specialized and specifics services. Before this qualitative perceive that the social and spacial differential of Nova Parnamirim was the responsible by soil and habitation valorization of ward, that reinforce the promotion of segregation and of auto-segregation, and consequently, of capitalist reproduction of urban space

Inquérito de saúde: comparação dos entrevistados segundo posse de linha telefônica residencial

OBJETIVO: Analisar diferenças quanto a características sociodemográficas e relacionadas à saúde entre indivíduos com e sem linha telefônica residencial. MÉTODOS: Foram analisados os dados do Inquérito de Saúde (ISA-Capital) 2003, um estudo transversal realizado em São Paulo, SP, no mesmo ano. Os moradores que possuíam linha telefônica residencial foram comparados com os que disseram não possuir linha telefônica, segundo as variáveis sociodemográficas, de estilo de vida, estado de saúde e utilização de serviços de saúde. Foram estimados os vícios associados à não-cobertura por parte da população sem telefone, verificando-se sua diminuição após a utilização de ajustes de pós-estratificação. RESULTADOS: Dos 1.878 entrevistados acima de 18 anos, 80,1% possuía linha telefônica residencial. Na comparação entre os grupos, as principais diferenças sociodemográficas entre indivíduos que não possuíam linha residencial foram: menor idade, maior proporção de indivíduos de raça/cor negra e parda, menor proporção de entrevistados casada, maior proporção de desempregados e com menor escolaridade. Os moradores sem linha telefônica residencial realizavam menos exames de saúde, fumavam e bebiam mais. Ainda, esse grupo consumiu menos medicamentos, auto-avaliou-se em piores condições de saúde e usou mais o Sistema Único de Saúde. Ao se excluir da análise a população sem telefone, as estimativas de consultas odontológicas, alcoolismo, consumo de medicamentos e utilização do SUS para realização de Papanicolaou foram as que tiveram maior vício. Após o ajuste de pós-estratificação, houve diminuição do vício das estimativas para as variáveis associadas à posse de linha telefônica residencial. CONCLUSÕES: A exclusão dos moradores sem linha telefônica é uma das principais limitações das pesquisas realizadas por esse meio. No entanto, a utilização de técnicas estatísticas de ajustes de pós-estratificação permite a diminuição dos vícios de não-cobertura.