Simulador computacional do comportamento em regime de poços de petróleo equipados com gas-lift contínuo

Amongst the results of the AutPoc Project - Automation of Wells, established between UFRN and Petrobras with the support of the CNPq, FINEP, CTPETRO, FUNPEC, was developed a simulator for equipped wells of oil with the method of rise for continuous gas-lift. The gas-lift is a method of rise sufficiently used in production offshore (sea production), and its basic concept is to inject gas in the deep one of the producing well of oil transform it less dense in order to facilitate its displacement since the reservoir until the surface. Based in the use of tables and equations that condense the biggest number of information on characteristics of the reservoir, the well and the valves of gas injection, it is allowed, through successive interpolations, to simulate representative curves of the physical behavior of the existing characteristic variable. With a simulator that approaches a computer of real the physical conditions of an oil well is possible to analyze peculiar behaviors with very bigger speeds, since the constants of time of the system in question well are raised e, moreover, to optimize costs with assays in field. The simulator presents great versatility, with prominance the analysis of the influence of parameters, as the static pressure, relation gas-liquid, pressure in the head of the well, BSW (Relation Basic Sediments and Water) in curves of request in deep of the well and the attainment of the curve of performance of the well where it can be simulated rules of control and otimization. In moving the rules of control, the simulator allows the use in two ways of simulation: the application of the control saw software simulated enclosed in the proper simulator, as well as the use of external controllers. This implies that the simulator can be used as tool of validation of control algorithms. Through the potentialities above cited, of course one another powerful application for the simulator appears: the didactic use of the tool. It will be possible to use it in formation courses and recycling of engineers

Controle automático para injeção otimizada de gás em poços de petróleo equipados para funcionamento com gás lift contínuo

The continuous gas lift method is the main artificial lifting method used in the oil industry for submarine wells, due to its robustness and the large range of flow rate that the well might operate. Nowadays, there is a huge amount of wells producing under this mechanism. This method of elevation has a slow dynamics due to the transients and a correlation between the injected gas rate and the of produced oil rate. Electronics controllers have been used to adjust many parameters of the oil wells and also to improve the efficiency of the gas lift injection system. This paper presents a intelligent control system applied to continuous gas injection in wells, based in production s rules, that has the target of keeping the wells producing during the maximum period of time, in its best operational condition, and doing automatically all necessary adjustments when occurs some disturbance in the system. The author also describes the application of the intelligent control system as a tool to control the flow pressure in the botton of the well (Pwf). In this case, the control system actuates in the surface control valve

Análise não-linear do campo de temperaturas desenvolvidas durante a soldagem do tipo TIG contínuo em placas delgadas

This study offers an analytical approach in order to provide a determination of the temperature field developed during the DC TIG welding of a thin plate of aluminum. The non-linear characteristics of the phenomenon, such as the dependence of the thermophysical and mechanical properties with temperature were considered in this study. In addition to the conductive heat exchange process, were taken into account the exchange by natural convection and radiation. A transient analysis is performed in order to obtain the temperature field as a function of time. It is also discussed a three-dimensional modeling of the heat source. The results obtained from the analytical model were be compared with the experimental ones and those available in the literature. The analytical results show a good correlation with the experimental ones available in the literature, thus proving the feasibility and efficiency of the analytical method for the simulation of the heat cycle for this welding process.

Efeitos dos exercícios aeróbio contínuo e intervalado na variabilidade da frequência cardíaca em adultos jovens saudáveis. Ensaio clínico aleatório

The high-intensity interval exercise has been described as an option for increasing physical activity and its use also being suggested in the therapeutic management of many conditions such as diabetes mellitus and heart failure. However, the knowledge of its physiological effects and parameters that can assure greater safety for interval exercise prescription; especially its effect on short- and medium-term (24 hours after exercise) exercise recovery, need to be clarified. This study objective was to evaluate the effect of continuous and interval aerobic exercise on the cardiac autonomic control immediate and medium term (24 hours), by assessing heart rate variability (HRV). The present study is a randomized crossover clinical trial in which healthy young individuals with low level of physical activity had the VFC 24 hours measured by a heart rate sensor and portable accelerometer (3D eMotion HRV, Kuopio, Finland) before and after continuous aerobic exercise (60-70% HR max, 21 min.) and interval exercise (cycle 1 min. 80-90% HR max, 2 min. at 50-60% HR max, duration 21 min.). HRV was measured in the time and frequency domain and the sympathovagal balance determined by the ratio LF / HF. Nonlinear evaluation was calculated by Shannon entropy. The data demonstrated delayed heart rate recovery immediate after exercise and lower HR after 24 hours compared to pre intervention values, especially in the interval exercise group. There was a tendency to higher predominance and representatives index values of sympathetic stimulation during the day in interval exercise group; however, without statistical significance. The study results help to clarify the effects of interval exercise on the 24 hours following interval exercise, setting parameters for prescription and for further evaluation of groups with metabolic and cardiovascular diseases.

Reabilitação cardíaca na insuficiência cardíaca crônica: efeitos de 12 semanas de treinamento intervalado x contínuo na função cardiopulmonar e qualidade de vida

Background: Cardiac Rehabilitation (CR) has effect on mortality in patients with heart failure (HF) chronic, and the exercise of the treatment of this patient. The most common exercise is ongoing training. Recently we have been studying the effects of interval training, but there is no consensus on the optimal dose of exercise. Objective: To evaluate the effects of interval aerobic training are superior to continuous aerobic training in patients with chronic HF. Methods: The clinical trial evaluated patients through cardiopulmonary test (CPX) and quality of life before and after the RC (3 times / 12 weeks). Patients were randomized into Group Interval Training (GTI - 85% of heart rate reserve - FCR), Continuous Training Group (GTC - 60% of HRR) and control group (CG) who received guidelines. Results: 18 patients were evaluated (mean age 44.7 ± 13.2 years and 35.2 ± 8.9% of left ventricular ejection fraction [LVEF]). Both groups were efficient to increase the peak VO2 and 15.1% (P = 0.02) in GTI and 16.1% (P = 0.01) GTC. As for the quality of life the GTI GTC showed improvement compared to the control group (P = 0.006). Hemodynamic mismatch events during the CPX were reduced after training in more GTC (patients 1 to 4) than in the GTI (5 to 3). Cardiac risk also decreased in the GTC (3 patients left the severe risk to take after training). Conclusion: Continuous training becomes more appropriate for improving fitness with little chance of developing cardiac event patients with chronic HF.

Papel da extensão e do trabalho junto à comunidade na formação médica

SILVA, Thiago Demétrio Nogueira Costa e; CORRÊA, Edison José; MARANHÃO, Técia Maria de Oliveira. O papel da extensão e do trabalho junto à comunidade na formação Médica. Revista Eletrônica Pesquisa Médica, v.1, n.3, p.9-13, jul./set. 2007

Desenvolvimento de coleções de fontes de informação eletrônica em bibliotecas universárias

O contexto hodierno caracteriza-se como um panorama de uso contínuo de informação nas mais variadas esferas da sociedade. A informação é usada em diversos contextos sob vários formatos e isso se torna possível com a evolução tecnológica realizada em ritmo acelerado, sobretudo nos últimos dois séculos. Essa evolução trouxe consigo a possibilidade ampliada de acesso à informação, mas por outro lado, impôs desafios circunstanciais no seu tratamento e difusão. Nos diversos tipos de unidades de informação, faz-se necessária a adoção de estratégias para a melhoria do gerenciamento e desenvolvimento das coleções, sobretudo as coleções digitais. De tal modo, o trabalho visa a traçar um panorama ligado às questões relacionadas à comunicação cientifica com a bibliotecas universitárias, com vistas a ampliar o debate sobre o desenvolvimento digital de coleções de periódicos em bibliotecas universitárias, bem como aspectos relacionados à adoção de critérios de seleção e avaliação destes itens de informação. Aborda os casos específicos, como o do Portal Capes e o SciELO como coleções digitais de periódicos sujeitos a estratégias de desenvolvimento das coleções. Aponta opções para a melhoria da gestão da coleção digital em bibliotecas universitárias. A metodologia empregada foi a de pesquisa bibliográfica em uso de fontes eletrônicas e convencionais, bem como análise de critérios utilizados na Avaliação e Coleções para Bibliotecas Universitárias e o Indicadores Qualis pela Condenação de Aperfeiçoamento de Pessoa de Ensino Superior (CAPES).

Educação superior em turismo: o profissional de turismo frente às competências exigidas pelo mercado de trabalho do setor hoteleiro em Natal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Práticas interdisciplinares no ensino superior: a experiência do curso de graduação em administração da UNAMA - Pará

This work addresses the study of interdisciplinarity in higher administration education, a topic of great relevance in the present context, due to guidelines issued by Ministry of Education through the National Curriculum Guidelines -NCGs for undergraduate courses in Management. The attention on the subject emerges from the gained experience of a researcher and teacher working as manager of an undergraduate course in Business Administration who set up interdisciplinarity through interdisciplinary projects in a management course pedagogical project at a private university in State of Pará/Brazil. The work rebuilds and reports experiences, and studies the practice of lecturers involved in those interdisciplinary actions. The study aimed to identify changes in pedagogical practices of teachers involved in the searched interdisciplinary experience. To address the questions that directed the work and achieve proposed objectives, from a qualitative approach, a significant bibliographical and documentary work was conducted on the topic. In the survey carried out on secondary sources such as publications of major authors and scientific papers reporting interdisciplinary experiences in higher administration education, it was found that interdisciplinarity for its ambiguous character is still poorly understood by teachers, and reports on its application in administration teaching are incipient. This study also used data collected from primary sources, from dialogues through interviews with educational fellows - teachers and officers of the institution that served as locus of the research, who had the opportunity to experience the studied interdisciplinary experience. Data were processed and analyzed using content analysis technique. Research results showed that teachers of the institution of research have a good understanding of meaning of interdisciplinarity as a link between disciplines; it was also found substantial evidence of changes in teaching practices and actions of such teachers based on their participation in interdisciplinary projects. Although the experience studied can be considered innovative and challenging, much needs to be done in the course management for achievement of interdisciplinary actions in the course, particularly regarding to the removal of institutional, methodological, psychosocial, epistemological obstacles in operationalizing interdisciplinary practices, with emphasis on the need of a process of continuous and specific training aiming at developing skills for interdisciplinary acting, to the extent that these education professionals do not perceive themselves able to act as interdisciplinary lecturers

A Performance como Outro Lugar da Escrita: Escritura, Autoperformance e Emergência

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Síntese, caracterização e estudo da regeneração do silicoaluminofosfato-11 (SAPO-11)

heterogeneous catalyst such as a silicoaluminophosphate, molecular sieve with AEL (Aluminophosphate eleven) structure such as SAPO-11, was synthesized through the hydrothermal method starting from silica, pseudoboehmite, orthophosphoric acid (85%) and water, in the presence of a di-isopropylamine organic template. For the preparation of SAPO-11 in a dry basis it was used as reactants: DIPA; H3PO4; SiO4; Pseudoboehmite and distilled water. The crystallization process occurred when the reactive hydrogel was charged into a vessel and autoclaved at 200ºC for a period of 72 hours under autogeneous pressure. The obtained material was washed, dried and calcined to remove the molecular sieves of DIPA. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), nitrogen adsorption (BET) and thermal analysis (TG/DTG). The acidic properties were determined using adsorption of nbutylamine followed by programmed thermodessorption. This method revealed that SAPO-11 shows an acidity that ranges from weak to moderate. However, a small quantity of strong acid sites could be detected there. The deactivation of the catalysts was conducted by artificial coking followed by the cracking of the n-hexane in a fixed bed with a continuous flow micro-reactor coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the regeneration and removal of the coke

Estudos comparativos do ciclo de regeneração de diferentes tipos de silicoaluminofosfatos

Different types of heterogeneous catalysts of the silicoaluminophosphate type, (SAPO-5, SAPO-11, SAPO-31, SAPO-34 and SAPO-41), molecular sieves with a: AFI, AEL, ATO, CHA and AFO structure, respectively, were synthesized through the hydrothermal method. Using sources such as hydrated alumina (pseudobohemita), phosphoric acid, silica gel, water, as well as, different types of organic structural templates, such as: cetyltrimethylammonium bromide (CTMABr), di-isopropylamine (DIPA), di-n- propylamine (DNPA) and tetraethylammonium hydroxide (TEOS), for the respective samples. During the preparation of the silicoaluminophosphates, the crystallization process of the samples occurred at a temperature of approximately 200 ° C, ranging through periods of 18-72 h, when it was possible to obtain pure phases for the SAPOs. The materials were furthermore washed with deionized water, dried and calcined to remove the molecules of the templates. Subsequently the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), absorption spectroscopy in the infrared region (FT-IR), specific surface area and thermal analysis via TG/DTG. The acidic properties were determined using adsorption of n-butylamine followed by programmed termodessorption. These methods revealed that the SAPO samples showed a typically weak to moderate acidity. However, a small amount of strong acid sites was also detected. The deactivation of the catalysts was conducted by artificially coking the samples, followed by n-hexane cracking reactions in a fixed bed with a continuous flow micro-reactor coupled on line to a gas chromatograph. The main products obtained were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin (model-free) kinetics method was used to determine the catalysts regeneration and removal of the coke

Estudo de reatores eletroquímicos para remoção de Cu2+ , Zn2+, Fenol e BTEX em água produzida

The production of water has become one of the most important wastes in the petroleum industry, specifically in the up stream segment. The treatment of this kind of effluents is complex and normally requires high costs. In this context, the electrochemical treatment emerges as an alternative methodology for treating the wastewaters. It employs electrochemical reactions to increase the capability and efficiency of the traditional chemical treatments for associated produced water. The use of electrochemical reactors can be effective with small changes in traditional treatments, generally not representing a significant additional surface area for new equipments (due to the high cost of square meter on offshore platforms) and also it can use almost the same equipments, in continuous or batch flow, without others high costs investments. Electrochemical treatment causes low environmental impact, because the process uses electrons as reagent and generates small amount of wastes. In this work, it was studied two types of electrochemical reactors: eletroflocculation and eletroflotation, with the aim of removing of Cu2+, Zn2+, phenol and BTEX mixture of produced water. In eletroflocculation, an electrical potential was applied to an aqueous solution containing NaCl. For this, it was used iron electrodes, which promote the dissolution of metal ions, generating Fe2+ and gases which, in appropriate pH, promote also clotting-flocculation reactions, removing Cu2+ and Zn2+. In eletroflotation, a carbon steel cathode and a DSA type anode (Ti/TiO2-RuO2-SnO2) were used in a NaCl solution. It was applied an electrical current, producing strong oxidant agents as Cl2 and HOCl, increasing the degradation rate of BTEX and phenol. Under different flow rates, the Zn2+ was removed by electrodeposition or by ZnOH formation, due the increasing of pH during the reaction. To better understand the electrochemical process, a statistical protocol factor (22) with central point was conducted to analyze the sensitivity of operating parameters on removing Zn2+ by eletroflotation, confirming that the current density affected the process negatively and the flow rate positively. For economical viability of these two electrochemical treatments, the energy consumption was calculated, taking in account the kWh given by ANEEL. The treatment cost obtained were quite attractive in comparison with the current treatments used in Rio Grande do Norte state. In addition, it could still be reduced for the case of using other alternative energy source such as solar, wind or gas generated directly from the Petrochemical Plant or offshore platforms

Desenvolvimento de uma unidade pirolítica com reator de cilindro rotativo: obtenção de bio-óleo

The demand for alternative sources of energy drives the technological development so that many fuels and energy conversion processes before judged as inadequate or even non-viable, are now competing fuels and so-called traditional processes. Thus, biomass plays an important role and is considered one of the sources of renewable energy most important of our planet. Biomass accounts for 29.2% of all renewable energy sources. The share of biomass energy from Brazil in the OIE is 13.6%, well above the world average of participation. Various types of pyrolysis processes have been studied in recent years, highlighting the process of fast pyrolysis of biomass to obtain bio-oil. The continuous fast pyrolysis, the most investigated and improved are the fluidized bed and ablative, but is being studied and developed other types in order to obtain Bio-oil a better quality, higher productivity, lower energy consumption, increased stability and process reliability and lower production cost. The stability of the product bio-oil is fundamental to designing consumer devices such as burners, engines and turbines. This study was motivated to produce Bio-oil, through the conversion of plant biomass or the use of its industrial and agricultural waste, presenting an alternative proposal for thermochemical pyrolysis process, taking advantage of particle dynamics in the rotating bed that favors the right gas-solid contact and heat transfer and mass. The pyrolyser designed to operate in a continuous process, a feeder containing two stages, a divisive system of biomass integrated with a tab of coal fines and a system of condensing steam pyrolytic. The prototype has been tested with sawdust, using a complete experimental design on two levels to investigate the sensitivity of factors: the process temperature, gas flow drag and spin speed compared to the mass yield of bio-oil. The best result was obtained in the condition of 570 oC, 25 Hz and 200 cm3/min, temperature being the parameter of greatest significance. The mass balance of the elementary stages presented in the order of 20% and 37% liquid pyrolytic carbon. We determined the properties of liquid and solid products of pyrolysis as density, viscosity, pH, PCI, and the composition characterized by chemical analysis, revealing the composition and properties of a Bio-oil.

Modelagem matemática para o transporte de partículas sujeitas a múltiplos mecanismos de retenção

Discrepancies between classical model predictions and experimental data for deep bed filtration have been reported by various authors. In order to understand these discrepancies, an analytic continuum model for deep bed filtration is proposed. In this model, a filter coefficient is attributed to each distinct retention mechanism (straining, diffusion, gravity interception, etc.). It was shown that these coefficients generally cannot be merged into an effective filter coefficient, as considered in the classical model. Furthermore, the derived analytic solutions for the proposed model were applied for fitting experimental data, and a very good agreement between experimental data and proposed model predictions were obtained. Comparison of the obtained results with empirical correlations allowed identifying the dominant retention mechanisms. In addition, it was shown that the larger the ratio of particle to pore sizes, the more intensive the straining mechanism and the larger the discrepancies between experimental data and classical model predictions. The classical model and proposed model were compared via statistical analysis. The obtained p values allow concluding that the proposed model should be preferred especially when straining plays an important role. In addition, deep bed filtration with finite retention capacity was studied. This work also involves the study of filtration of particles through porous media with a finite capacity of filtration. It was observed, in this case, that is necessary to consider changes in the boundary conditions through time evolution. It was obtained a solution for such a model using different functions of filtration coefficients. Besides that, it was shown how to build a solution for any filtration coefficient. It was seen that, even considering the same filtration coefficient, the classic model and the one here propposed, show different predictions for the concentration of particles retained in the porous media and for the suspended particles at the exit of the media