Capacidade de absorção de energia de tubos de compósitos submetidos à compressão

Structures capable of absorbing large amounts of energy are of great interest, particularly for the automotive and aviation industries, to reduce tbe impact on passengers in the case of a collision. The energy absorption properties of composite materials structures can be tailored, thus making these structures an appealing option a substitute of more traditional structures in applications where energy absorption is crucial. ln this research, the influence of some parameters, which affect the energy absorption capacity of composite material tubes, was investigated. The tubes were fabricated by hand lay-up, using orthophthalic polyester resin and a plain weave E-glass fabric Test specimens were prepared and tested under compression load. The ínfluence of the following parameters on the specific energy absorption capacity of the tubes was studied: fiber configuration (0/90º or ± 45°), tube cross-section (circular or square), and processing conditions (with or without vacuum). The results indicated that circular cross-section tubes with fibers oriented at 0/90º presented the highest level of specific energy absorbed. Further, specimens from tubes fabricated under vacuum displayed higher energy absorption capacity, when compared with specimens from tubes fabricated without vacuum. Thus, it can be concluded that the fabrication process with vacuum produce composite structures with better energy absorption capacity

Efeito de adições poliméricas na aderência de pastas de cimento a tubos metálicos após ciclagem térmica

Thermal recovery methods, especially steam injection, have been used to produce heavy oils. However, these methods imply that the metallic casing-cement sheath interface is submitted to thermal cycling. As a consequence, cracking may develop due to the thermal expansion mismatch of such materials, which allows the flow of oil and gas through the cement sheath, with environmental and economical consequences. It is therefore important to anticipate interfacial discontinuities that may arise upon Thermal recovery. The present study reports a simple alternative method to measure the shear strength of casing-sheath interfaces using pushthrough geometry, applied to polymer-containing hardened cement slurries. Polyurethane and recycled tire rubber were added to Portland-bases slurries to improve the fracture energy of intrinsically brittle cement. Samples consisting of metallic casing sections surrounded by hardened polymer-cement composites were prepared and mechanically tested. The effect of thermal cycles was investigated to simulate temperature conditions encountered in steam injection recovery. The results showed that the addition of polyurethane significantly improved the shear strength of the casing-sheath interface. The strength values obtained adding 10% BWOC of polyurethane to a Portland-base slurry more than doubled with respect to that of polyurethane-free slurries. Therefore, the use of polyurethane significantly contributes to reduce the damage caused by thermal cycling to cement sheath, improving the safety conditions of oil wells and the recovery of heavy oils

Estudo de um isolante térmico para tubos fabricado em material compósito

It presents a new type of insulation for ductwork hot water, which can be used in solar systems for heating water, which consists of a composite of different compositions based on plaster, cement and EPS ground, palm and water. This composite has as its main features easy assembly and manufacturing processes and low cost. Comparative results will be presented on the tests of materials and thermal tubes proposed. Four formulations were used to manufacture tubes with three diameters 70, 65 and 42mm. It was also tested conventionally used for elastomeric foam insulation to 110 ° C, for a comparative analysis with the composite pipe insulator proposed. It will demonstrate that the cost of manufacturing of such tubes is competitive with alternative elastomeric foam tested, but results of the composite tube to the temperature range studied, are lower. Another drawback of the composite insulator tube is its large mass. It would be important to test such a composite for greater levels of temperature to a diagnostic technique competitive with conventionally used insulators. A positive factor of using the proposed composite-tube would be the recycling of EPS so damaging to the environment, representing an environmentally friendly application of science

Modelagem e simulação da solubilização da parafina em tubos circulares e em regime laminar

O óleo produzido nos novos campos de petróleo está cada vez mais parafínico e viscoso, com isso, à medida que o óleo é escoado, parafinas são depositadas sobre as paredes internas do tubo, e ao longo do tempo, tendem a reduzir drasticamente a área transversal ao escoamento. Visando estudar o processo de solubilização da parafina em dutos, esse trabalho objetiva desenvolver modelos matemáticos que represente o processo, com base nos fenômenos envolvidos no mesmo tais como transferência de massa, transferência de energia e equilíbrio sólido-líquido, implementando-os em um ambiente de desenvolvimento VBA (Visual Basic) for Excel ®. O presente trabalho foi realizado em quatro etapas: i) modelagem dos fenômenos de transferência de calor e massa, ii) modelagem da rotina dos coeficientes de atividade através do modelo UNIFAC e modelagem do sistema de equilíbrio sólido-líquido; iii) modelagem matemática do processo de solubilização e cálculo da espessura da parafina ao longo do tempo; iv) implementação dos modelos em um ambiente de desenvolvimento VBA for Excel® e criação de um simulador com uma interface gráfica, para simular o processo de solubilização da parafina depositada em dutos e sua otimização. O simulador conseguiu produzir soluções bastante adequadas, mantendo continuidade das equações diferenciáveis do balanço de energia e de massa, com uma interpretação física viável, sem a presença de dissipação de oscilações nos perfis de temperatura e massa. Além disso, esse simulador visa permitir a simulação nas diversas condições de escoamento, bem como compreender a importância das variáveis (vazão, temperatura de entrada, temperatura externa, cadeia carbônica do solvente). Através dos resultados foram possíveis verificar os perfis de temperatura, fração molar e o de solubilização

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

A sala de aula em cena: uma pesquisa em ensino do teatro a partir da experiência docente

At first moment we present a reflection about the history of theater and later a contextualization of didactic movements oriented to scenic arts. Through at the constant dialogue with authors of areas involving education, theatre, corporeality and music was possible analyzing, develop and criticize a education work under my responsibility involving fourteen classes. At the second moment will occur a critical self about the quality of theater classes his contents and methodologies. The technique will be at side of the emotion and together develop skills aimed at tracing paths for theater developed at a classroom of a especific private school in Natal-RN. At the third moment one class is chosen for analyze of the academic research and many experiments happen after this decision, initiated and sensitized through of the music with a significant look at the corporeality and prioritizing the theater as content in ninth grade - elementary school two. At the conclusion is possible see that learning is mutual and the theater can become life routine as well as the arts in general and when all arts will be regularized into the national educational system for public and private schools we will have more susceptible humans and more intellectual capacity

Efeito do Fucoidam de Fucus vesiculosus em um modelo experimental de artrite reumatóide

Rheumatoid arthritis (RA) is systemic auto imune disorder. It is caracterized by chronic inflammation of joints leading to progressive erosion of cartilage and bone. We investigated the effect of the administration of fucoidan, sulfated polysaccharides, from algae Fucus vesiculosus in the acute (6h) in zymosan-induced arthritis (AZy). Wistar rats (180-230 g) were used for all groups experimental. Non-treated animals received just intraarticular injection of 1 mg the zymosan, control group received intraarticular injection of 50 µL the saline, groups received either fucoidan of Fucus vesiculosus (15, 30, 50 or 70 mg/Kg) or parecoxib (1 mg/Kg) 1 hour after injection of zymosan. After 6 h, the articular exudates were collected for evaluation of the cell influx and nitrite (Griess reaction) release. The sinovial membranes and articular cartilages were excised for histopathological analysis and by determination of the glycosaminoglycan (GAG), respectively. ZyA led to increased NO and cell influx into the joints. Therapeutic administration of the fucoidan or parecoxib did significantly inhibited the cell influx and the synovitis, as compared to non-treated rats (p<0,05), though being able to reduced NO release. Representative agarose gel electrophoresis of the GAGs, the content of condroitin-sulphate was observed during the process. These findings suggest that the fucoidan from Fucus vesiculosus has potential anti-inflammatory activity

Desenvolvimento de tubulação em compósito polimérico revestida externamente com poliuretano de alta densidade

Pipelines for the transport of crude oil from the production wells to the collecting stations are named production lines . These pipes are subjected to chemical and electrochemical corrosion according to the environment and the type of petroleum transported. Some of these lines, depending upon the composition of the fluid produced, may leak within less than one year of operation due to internal corrosion. This work aims at the development of composite pipes with an external protecting layer of high density polyurethane for use in production lines of onshore oil wells, meeting operational requirements. The pipes were manufactured using glass fibers, epoxy resin, polyester resin, quartz sand and high density polyurethane. The pipes were produced by filament winding with the deposition of high density polyurethane on the external surface and threaded ends (API 15 HR/PM-VII). Three types of pipes were manufactured: glass/epoxy, glass/epoxy with an external polyurethane layer and glass/epoxy with an intermediate layer of glass fiber, polyester, sand and with an external polyurethane layer. The three samples were characterized by Scanning Electronic Microscopy (SEM) and for the determination of constituent content. In addition, the following tests were conducted: hydrostatic test, instant rupture, shorttime failure pressure, Gardner impact, transverse stiffness and axial tension. Field tests were conducted in Mossoró RN (BRAZIL), where 1,677 meters of piping were used. The tests results of the three types of pipes were compared in two events: after two months from manufacturing of the samples and after nine months of field application. The results indicate that the glass/epoxy pipes with an intermediate layer of fiber glass composite, polyester e sand and with an external layer of high density polyurethane showed superior properties as compared to the other two and met the requirements of pressure class, axial tensile strength, transverse stiffness, impact and environmental conditions, for onshore applications as production lines

Cinemática de partículas em fluidos de viscosidade variável com o tempo e sua aplicação na construção de poços de petróleo: avaliação durante paradas operacionais

The new oil reservoirs discoveries in onshore and ultra deep water offshore fields and complex trajectories require the optimization of procedures to reduce the stops operation during the well drilling, especially because the platforms and equipment high cost, and risks which are inherent to the operation. Among the most important aspects stands out the drilling fluids project and their behavior against different situations that may occur during the process. By means of sedimentation experiments, a correlation has been validated to determe the sedimentation particles velocity in variable viscosity fluids over time, applying the correction due to effective viscosity that is a shear rate and time function. The viscosity evolution over time was obtained by carrying out rheologic tests using a fixed shear rate, small enough to not interfere in the fluid gelling process. With the sedimentation particles velocity and the fluid viscosity over time equations an iterative procedure was proposed to determine the particles displacement over time. These equations were implemented in a case study to simulate the cuttings sedimentation generated in the oil well drilling during stops operation, especially in the connections and tripping, allowing the drilling fluid project in order to maintain the cuttings in suspension, avoiding risks, such as stuck pipe and in more drastic conditions, the loss of the well

Seleção de categorias da Classificação Internacional de Funcionalidade, Incapacidade e Saúde para avaliação do paciente com acidente vascular cerebral em reabilitação

Stroke represents the first cause of disabilities among adults. Although different professions work together in treatment of stroke patients, all they use different terminologies for the description of the patients problems and it can constitute an impediment in the communication between the staff members. Thus, the multidisciplinary and interdisciplinary work would be facilitated if using a reference common tool, as the new International Classification of Functioning, Disability and Health (ICF). However, the ICF is very extensive and complex and due to its complexity, it has been evidenced the necessity to select its categories to become it more practical. The aim of the study was to investigate which categories of the ICF are more suitable to evaluate and to describe the stroke patient in the view of teachers and municipal public health professionals. It was a descriptive research, which involved 5 professors and 11 professionals of Physiotherapy that have worked at the health public area in Natal / RN. It was used the Delphi Technique in 3 rounds and the Likert Scale to select the categories among the ICF components. As result, from the 362 IFC categories, 94 were selected. The selected categories correspond to rehabilitative characteristics of Stroke patients in the universe of the Physiotherapy performance. The methodology applied was suitable to the studied object emphasizing the necessity of future studies for validation of the chosen categories

Avaliação da eficácia analgésica no pós-operatório de revascularização do miocárdio: ensaio clínico randomizado controlado

A analgesia pós-operatória eficaz é especialmente importante após cirurgias torácicas, pois, além de aliviar a dor, facilita a retomada de atividades normais, incluindo a deambulação, a respiração e a tosse. Dessa forma, os objetivos deste estudo são: avaliar a eficácia analgésica da associação entre anestesia geral e raquianestesia com morfina e ropivacaína mais esquema multimodal em relação à anestesia geral e esquema multimodal em cirurgia de revascularização do miocárdio; analisar a eficácia analgésica da injeção subcutânea de lidocaína e analgesia multimodal na remoção de tubos torácicos em cirurgia de revascularização do miocárdio. A metodologia consiste em ensaio clínico randomizado, controlado, envolvendo 58 pacientes, de ambos os sexos, com idade média de 59,8  8,9 anos, estado físico ASA II e III. Os participantes foram alocados em dois grupos, sendo o GI composto por indivíduos submetidos à anestesia geral combinada à raquianestesia com morfina 400μg e 6 ml (30mg) a 8 ml (40mg) de ropivacaína a 0,5% e analgesia multimodal; já o GII foi composto por indivíduos submetidos à anestesia geral associada à analgesia multimodal. Foi avaliada a dor, ao despertar, nas primeiras 24 horas, e ao realizar exercício respiratório, ao retirar drenos de torácicos e o tempo para extubação. A análise estatística foi realizada pelos testes do Qui-quadrado e Teste t de Student e o teste de Fisher. O resultado obtido foi o seguinte: o GI apresentou menor intensidade de dor ao despertar (p= 0,001), nas primeiras 24 horas (p= 0,001) e durante a realização dos exercícios respiratórios (p= 0,004). Houve maior necessidade de analgesia complementar no grupo GII, com maior consumo de morfina (p= 0,05), e os efeitos colaterais leves, como náuseas (p= 0,001), vômito (p= 0,002), prurido (p= 0,030), predominaram no GI. Não houve diferença estatisticamente significante entre os grupos (P= 0,47), em relação à intensidade de dor na remoção dos drenos. Após as observações feitas, o estudo sugere que a anestesia geral combinada à raquianestesia com morfina associada à ropivacaína oferece melhor efeito analgésico no pós-operatório de cirurgia cardíaca. Adicionalmente, o estudo sugere que o efeito analgésico da injeção subcutânea de lidocaína 1% associado à analgesia multimodal não é eficaz

A transformação da Associação de Professores do Rio Grande do Norte (APRN) em Sindicato dos Trabalhadores em Educação (1986-1990)

El estudo que ahora apresentamos habla a respecto ala transformaçión de la Asociación de maestros del Rio Grande del Norte (APRN en sindicato de los trabajadores en educación (SINTE) en el período de 1986 1990. Tratase basicamiente de las razones que llebaran historicamente la APRN la reorganizar sus luchas, su cultura política y el su movimiento reivindicatório; que impulsionaran la construción del próprio sindicato el único de la categoria, após el regime militar em el país especialmente en el gobierno Sarney, y en el ánbito estadual com la resistência la política econômica y la repreción policial del gobierno Geraldo Melo, la época. El estudo también apunta algunas caraterísticas marcantes del contexto histórico de la educación nacional, enfatizando la asención de la escuela nueva en el Brasil en las décadas de 1920 y 1930, inclusive delante del movimiento sindical, controlado por el gobierno Vargas que tênia uma praetica corporativista. Es importante decir que esas características estavan juntas del contexto local, en el rato en que se percebia la primer gestan del prof Anfilóquio Cámara, como el primer presidente de la APRN, al partir de la su fundación (1920), y que tênia um relacionamento bastante estrecho com el poder público estadual de caráter liberal. Habia una discución sobre la abertura política y la atuación política de las clases médias brasileñas ya em 1979, y al mismo tiempo analisabase el desencandeamiento del nuevo sindicalismo en el ABC Paulista, mientras uno movimiento sindical, autônomo y democrático que tênia el objetivo de juntar lãs luchas de los operários dentro y fuera de las fábricas reivindicando basicamiente: la redución de la jornada del trabajo, reajuste de sueldo y condición del trabajo, bien como lãs sus consecuencias para el movimiento de los educadores potigurares. Al hacer en septembre de 1989, el sindicato de los trabajadores en educación del Rio Grande del Norte se desvincula definitivamiente de uma estructura sindical vertical (tradicional), que la ex-APRN herdo al longo de su História del gobierno Vargas, siempre controlada pelo Estado y que en las décadas de 1980 y 1990 fue fortalecido por la CNTE (Confederación Nacional de los Trabajadores en la, educación), principalmente, a partir del Congreso Nacional de Unificación de los Trabajadores en la Educación, realizado en Aracaju/SE em el período de 25 a 28 de enero de 1990 en el sentido tambien de las sus principais reivindicaciones: escuela pública, gratuita y de cualidades en todos los pasos, verbas públicas solamiente para las escuelas públicas, reposición de los reajustes de sueldo, condición del trabajo, sueldo unificado nacional y la eradicación del analfabetismo

A interação nas distâncias: a análise de um processo

Education and technology have always walked side by side. The Information and Communication Technologies are inserted in education as a profile of people from the new era. This research has the objective of understanding the insertion of the use of the Technologies of Information and Communication within the educational context, from the analysis of the process of interactivity among students and teachers of the Portuguese distance course of the Tiradentes University (Unit). For such, the empiric investigation was based on the analysis of academic documents, such as: the Course Pedagogical Project and Class Planning of regular classes, in regular classrooms, as well as interviews, focal groups, and pictures with people who live the history of the course. Direct observations were also conducted. The methodology applied was bibliographic and qualitative research of the exploratory type, using the information that was collected through the interviews. The results of this research demonstrated that the interaction promoted by the ICT represents a process of social change, and therefore, of development for education. It was concluded that the Distance Education has to overcome some fragilities, aiming at contributing to the educational field and to the promotion of interactions among students

Utilização intracoágulo de espuma fibrinolítica - preparação, caracterização e atividade in vitro de uma espuma de estreptoquinase e proposta de uma nova abordagem terapêutica

Foam was developed as a novel vehicle for streptokinase with the purpose of increasing the contact time and area between the fibrinolytic and the target thrombus, which would lead to a greater therapeutic efficacy at lower doses, decreasing the drug s potential to cause bleeding. Fibrinolytic foams were prepared using CO2 and human albumin (at different v:v ratios), as the gas and liquid phases, respectively, and streptokinase at a low total dose (100,000 IU) was used as fibrinolytic agent conveyed in 1 mL of foam and in isotonic saline solution. The foams were characterized as foam stability and apparent viscosity. The thrombolytic effect of the streptokinase foam was determined in vitro as thrombus lysis and the results were compared to those of a fibrinolytic solution (prepared using the same dose of streptokinase) and foam without the fibrinolytic. In vitro tests were conducted using fresh clots were weighed and placed in test tubes kept at 37 ° C. All the samples were injected intrathrombus using a multiperforated catheter. The results showed that both foam stability and apparent viscosity increased with the increase in the CO2:albumin solution ratio and therefore, the ratio of 3:1 was used for the incorporation of streptokinase. The results of thrombus lysis showed that the streptokinase foam presented the highest thrombolytic activity (44.78 ± 9.97%) when compared to those of the streptokinase solution (32.07 ± 3.41%) and the foam without the drug (19.2 ± 7.19%). We conclude that fibrinolytic foam showed statistically significant results regarding the enhancement of the lytic activity of streptokinase compared to the effect of the prepared saline solution, thus it can be a promising alternative in the treatment of thrombosis. However, in vivo studies are needed in order to corroborate the results obtained in vitro

Efeitos individuais e interativos da diversidade de detritos, contexto e variabilidade ambiental sobre a magnitude e estabilidade do processo de decomposição

Studies on the effects of changes in biodiversity and ecosystem functioning have been a central theme in ecology over the past two decades. Several studies have showed that the diversity of plant debris differently affects the decomposition process in aquatic and terrestrial environments, but we know very about the effects of detritus diversity on decomposition under fluctuating environmental conditions. We tested whether and how the environmental contexts, as well as the dynamic of their alternation, influence the effects of detritus diversity on the decomposition process. We performed a field experiment where we manipulate the litter diversity of 8 species of terrestrial plants decomposing (litterbags) in single and in mixture containing the eight species together in three different environmental contexts: the terrestrial environment (T), aquatic (A) and interface (I) - experimental treatment that simulates variation in flooding regime. We measured the rate of decomposition through the loss of mass of the community and each individual detritus in monocultures and mixtures. Species richness and environmental variability had no effects on the magnitude and stability of the decomposition process. However, there were significant diversity effects on the decomposition of an individual alien species, F. benjamina. Environmental context had significant effects on the magnitude and variability of decomposition. Detritus decomposition was faster and more variable on aquatic, interface and terrestrial conditions, respectively. Our results demonstrate that the diversity of plant detritus has minor effects to the decomposition across disparate environmental conditions and suggest that it is necessary to consider the potential of other abiotic factors in affect the magnitude and variability of the decomposition processes