Modelagem numérica de escoamento em padrão anular com transferência de calor e massa

Annular flow is the prevailing pattern in transport and energy conversion systems and therefore, one of the most important patterns in multiphase flow in ducts. The correct prediction of the pressure gradient and heat transfer coefficient is essential for optimizing the system s capacity. The objective of this work is to develop and implement a numerical algorithm capable of predicting hydrodynamic and thermal characteristics for upflow, vertical, annular flow. The numerical algorithm is then complemented with the physical modeling of phenomena that occurs in this flow pattern. These are, turbulence, entrainment and deposition and phase change. For the development of the numerical model, axial diffusion of heat and momentum is neglected. In this way the time-averaged equations are solved in their parabolic form obtaining the velocity and temperature profiles for each axial step at a time, together with the global parameters, namely, pressure gradient, mean film thickness and heat transfer coefficient, as well as their variation in the axial direction. The model is validated for the following conditions: fully-developed laminar flow with no entrainment; fully developed laminar flow with heat transfer, fully-developed turbulent flow with entrained drops, developing turbulent annular flow with entrained drops, and turbulent flow with heat transfer and phase change

Análise aerodinâmica de perfis de asa para aeronaves experimentais tipo jn-1

The great importance in selecting the profile of an aircraft wing concerns the fact that its relevance in the performance thereof; influencing this displacement costs (fuel consumption, flight level, for example), the conditions of flight safety (response in critical condition) of the plane. The aim of this study was to examine the aerodynamic parameters that affect some types of wing profile, based on wind tunnel testing, to determine the aerodynamic efficiency of each one of them. We compared three types of planforms, chosen from considerations about the characteristics of the aircraft model. One of them has a common setup, and very common in laboratory classes to be a sort of standard aerodynamic, it is a symmetrical profile. The second profile shows a conFiguration of the concave-convex type, the third is also a concave-convex profile, but with different implementation of the second, and finally, the fourth airfoil profile has a plano-convex. Thus, three different categories are covered in profile, showing the main points of relevance to their employment. To perform the experiment used a wind tunnel-type open circuit, where we analyzed the pressure distribution across the surface of each profile. Possession of the drag polar of each wing profile can be, from the theoretical basis of this work, the aerodynamic characteristics relate to the expected performance of the experimental aircraft, thus creating a selection model with guaranteed performance aerodynamics. It is believed that the philosophy used in this dissertation research validates the results, resulting in an experimental alternative for reliable implementation of aerodynamic testing in models of planforms

Método de Otimização Topológica em Estruturas Tridimensionais

The topology optimization problem characterize and determine the optimum distribution of material into the domain. In other words, after the definition of the boundary conditions in a pre-established domain, the problem is how to distribute the material to solve the minimization problem. The objective of this work is to propose a competitive formulation for optimum structural topologies determination in 3D problems and able to provide high-resolution layouts. The procedure combines the Galerkin Finite Elements Method with the optimization method, looking for the best material distribution along the fixed domain of project. The layout topology optimization method is based on the material approach, proposed by Bendsoe & Kikuchi (1988), and considers a homogenized constitutive equation that depends only on the relative density of the material. The finite element used for the approach is a four nodes tetrahedron with a selective integration scheme, which interpolate not only the components of the displacement field but also the relative density field. The proposed procedure consists in the solution of a sequence of layout optimization problems applied to compliance minimization problems and mass minimization problems under local stress constraint. The microstructure used in this procedure was the SIMP (Solid Isotropic Material with Penalty). The approach reduces considerably the computational cost, showing to be efficient and robust. The results provided a well defined structural layout, with a sharpness distribution of the material and a boundary condition definition. The layout quality was proporcional to the medium size of the element and a considerable reduction of the project variables was observed due to the tetrahedrycal element

Análise térmica e mecânica de um compósito de matriz cerâmica com carga de EPS e raspa de pneu para construção de casas populares

Space Science was built using a composite made of plaster, EPS, shredded tires, cement and water. Studies were conducted to thermal and mechanical resistance. Inside the mold EPS plates were placed in order to obtain a higher thermal resistance on the wall constructed, as well as to give it an end environmentally friendly in view of both the tire and the EPS occupy a large space in landfills and year need to be degraded when released into the environment. Compression tests were performed according to ABNT blocks to seal, measurements of the temperature variation in the external and internal walls using a laser thermometer and check the temperature of the indoor environment using a thermocouple attached to a digital thermometer. The experiments demonstrated the heat provided by the composite values from the temperature difference between the internal and external surfaces on the walls, reaching levels of 12.4 ° C and room temperature in the interior space of the Science of 33.3 ° C, remaining within the zone thermal comfort for hot climate countries. It was also demonstrated the proper mechanical strength of such a composite for sealing walls. The proposed use of the composite can contribute to reducing the extreme housing shortage in our country, producing popular homes at low cost and with little time to work

Estudo de um compósito de matriz cerâmica com carga de recicláveis para o uso na construção civi

With a view to revitalizing public environments through criteria that include economy, tourism, aesthetics and respect for the environment, this paper proposes a model of kiosk manufactured with composite material blocks, to be employed as a public instrument. . The model consists of a structure composed of planned blocks and manufactured in cement-based composite, gypsum, ground and water, having the styrofoam inside filled with pet bottles of 500 ml dose. The social and environmental issue is the critical point of the work when it can, through the reuse of environmentally harmful materials such as polyethylene terephthalate PET, using such modules for the construction of various areas of Commerce, promoting the protection of the environment combined with the improvement of the quality of life of the population. The tourism factor, which is significant in the economy of the North, is also considered as the modulated kiosk has a visual aspect innovative and differentiated. The environmental issue is addressed by encouraging the reuse of PET material and EPS (polystyrene)

Controle por modos deslizantes com compensação difusa aplicado a sistemas com descontinuidade

The development of non-linear controllers gained space in the theoretical ambit and of practical applications on the moment that the arising of digital computers enabled the implementation of these methodologies. In comparison with the linear controllers more utilized, the non -linear controllers present the advantage of not requiring the linearity of the system to determine the parameters of control, which permits a more efficient control especially when the system presents a high level of non-linearity. Another additional advantage is the reduction of costs, since to obtain the efficient control through linear controllers it is necessary the utilization of sensors and more refined actuators than when it is utilized a non-linear controller. Among the non-linear theories of control, the method of control by gliding ways is detached for being a method that presents more robustness, before uncertainties. It is already confirmed that the adoption of compensation on the region of residual error permits to improve better the performance of these controllers. So, in this work it is described the development of a non-linear controller that looks for an association of strategy of control by gliding ways, with the fuzzy compensation technique. Through the implementation of some strategies of fuzzy compensation, it was searched the one which provided the biggest efficiency before a system with high level of nonlinearities and uncertainties. The electrohydraulic actuator was utilized as an example of research, and the results appoint to two configurations of compensation that permit a bigger reduction of the residual error

Avaliação dos impactos ambientais gerados por uma industria cerâmica típica da Região do Seridó/RN

The present work deals with an evaluation of the environmental impacts arised from a typical ceramics industry located in the Seridó region of Rio Grande do Norte State. That region contains the largest State s producing basin of red ceramics. The district of Parelhas stands out as the largest producing nucleus. The studied company is located in the rural zone of Parelhas, it was selected as study object because it possesses a great part of the representative characteristics of the Region s ceramics park as a whole. Impacts produced at the implantation and operation phases of the Company had been evaluated, being this last phase subdivided in stages of the productive process. Among found adverse impacts, they are distinguished: losses in air quality, undesirable noises, microclimatic alterations, impoverishment of the ground, elimination of the vegetal covering, agricultural exodus, crisis in cattle agriculture and, superficial and underground water contamination, beyond risks ocupational diseases and industrial accidents. The Leopold s interactive matrix, that summarizes results of the work, was presented in form of 15 (fifteen) tables that display impacts classified in qualitative and quantitative way. Totally, 175 (one hundred and seventy-five) significant impacts produced by this Company had been identified, being 114 (one hundred and fourteen) negative, 38 (thirty-eight) positive and 23 (twenty-three) among mixed, indefinite and inert ones. In the work, before the evaluation of impacts properly said, it was constructed a diagnostic table of the ambient situation at a previous moment to implantation of the Company, elaborated on basis of inferences and historical researches. It was proposed still, mitigative steps for adverse impacts identified, as also elaborated a program to accompaniment and observing that the fulfilment of indicated mitigative steps guarantees. The final part of the work contemplates conclusions and suggestions that aim to influence positively the presented sight in terms of environmental management

Estudo da oxidação do metabissulfito de sódio contido no efluente da carcinicultura

The shrimp farming is a process of creation of shrimp that has been growing rapidly in the country, occupying a meaningful space in the Brazilian exporting. In 2003, this activity presented a volume of 60 millions of tons and 220 millions of dollars, being the main generator of employment and income of the primary sector of the northeast economy. However, it is a new activity with c.a. five years in the Rio Grande do Norte State and therefore needs investment in the technological area. Among the wastewaters of this activity, the sulphite solution is being usually applied in the process of fishing, i.e. retrieval of the shrimps from the farming. The aim of this work is to present the oxidation experimental results of the sulphite that may be and to determine what it s the most efficient method, trough laboratory experiments. The measurements were carried out in a mixing reactor inserting air and with hydrogen peroxide addition with and without UV light. The solutions were prepared synthetically with concentrations found in the wastewater of fishing and also collected in locu. The oxidation process using air was monitorated by iodometric analysis for the sulphite and the oxidation using hydrogen peroxide was evaluated with turbidimetric analysis for sulphate, by spectrophotometer. The sulphite was totally oxidized in both processes. The experimental results permit to conclude that the oxidation by hydrogen peroxide is more efficient and allowed to determine the optimum operational conditions in terms of concentration and time of treatment

Limonologia e qualidade ambiental de um corpo lêntico receptor de efluentes tratados da indústria de petróleo

Environmental pollution has become a subject of public interest throughout the world. Not only have developed countries been affected by environmental problems but also the developing nations have started to suffer from the serious impacts of pollution. Within this context it is necessary to collect simplified environmental data to assist in the management of water resources by the appropriate authorities. These data are obtained through an environmental index that allows a space-time comparison of points distributed in the same aquatic body, or between different water bodies, for physico-chemical and bacteriological parameters. The aim of this present study was to determine the environmental status of the Lagoa de Baixo at Guamaré/RN, where a production unit of PETROBRAS RN/CE is located. For this purpose the Water Quality Index (WQI) was used in both an add and multiply form, the Trophic State Index (TSI) and the Environmental Quality Quotient (EQQ), as well as determining the concentrations of metals. The average values obtained for the WQI, in its two forms were 68,67 and 62,76 respectively which were inside the good qualification. According to the TSI the lagoon showed characteristics of a middle trophic state, and an impact level of regular as determined by the EQQ

Estudo das características físico-químicas e funcionalidade de bagaços de frutas tropicais desidratados em leito de jorro

Fruits are rich sources of bioactive compounds, including phenolic compounds. Tropical fruit cultivation is an important productive segment in Brazilian Northeast. Its industrialization generates solid wastes as co-products, with potential environmental impact. Considering the recognized bioactive content of fruit and its derivatives, this research has the objective of investigating acerola (Malpighia glabra L.), cajá-umbu (Spondia ssp), jambolan (Syzygium cumini) and pitanga (Eugenia uniflora) dried wastes obtained by spouted bed drier. It was analyzed the physical-chemical composition, solubility and microphotographic aspect of these dried wastes. Besides this, it was also evaluated the bioactive content, antioxidant activity and inhibitory activity against aamylase and a-glycosidase enzymes of water and ethanol (70%, 80% e 100% v/v) extracts prepared from fruit dried wastes, as well as their possible correlations. The dried fruit wastes showed high phenolic (606.04 to 3074.6 mg GAE eq/100 g sample), anthocyanin (478.7 mg/100 g for jambolan) and ascorbic acid (2748.03 mg/100 g for acerola) contents, as well as high antioxidant DPPH activity (14.27 a 36.30 mg Trolox eq/g sample). The extracts exhibited moderate to high a-amylase inhibition (23.97% a 76.58%) and high α-glycosidase inhibition, which 99.32% peak was reached for ethanol 70% pitanga extracts. It was also observed great positive correlation between phenolic content and DPPH activity (0.97 for acerola), anthocyanin (0.95 for jambolan) and α- glycosidase inhibition (0.98 for acerola). The α-glycosidase inhibition also correlated well with the antioxidant activity for all fruit extracts. The results show that these dried fruit wastes are valuable material for further applications as functional ingredients

Avaliação da aplicação de modelos para a secagem de pastas e suspensões em leito de jorro com alimentação contínua

This work studies the development, implementation and improvement of a macroscopic model to describe the behavior of the spouted bed dryer with continuous feeding for pastes and suspensions drying. This model is based on the CST model (Freire et al., 2009) and the model of Fernandes (2005), whose theoretical foundation is based on macroscopic mass and heat balances for the three phases involved in the process: gas, liquid and solid. Because this technique is quite relevant, the studies of modeling and simulation of spouted bed drying are essential in the analysis of the process as a whole, because through them it is possible to predict and understand the behavior of the process, which contributes significantly to more efficient project and operation. The development and understanding of the phenomena involved in the drying process can be obtained by comparing the experimental data with those from computer simulations. Such knowledge is critical for choosing properly the process conditions in order to obtain a good drying efficiency. Over the past few years, researches and development of works in the field of pastes and suspensions drying in spouted bed has been gaining ground in Brazil. The Particulate Systems Laboratory at Universidade Federal do Rio Grande do Norte, has been developing several researches and generating a huge collection of experimental data concerning the drying of fruit pulps, vegetables pastes, goat milk and suspensions of agro-industrial residues. From this collection, some data of goat milk and residue from acerola (Malpighia glabra L.) drying were collected. For the first time, these data were used for the development and validation of a model that can describe the behavior of spouted bed dryer. Thus, it was possible to model the dryer and to evaluate the influence of process variables (paste feeding, temperature and flow rate of the drying air) in the drying dynamics. We also performed water evaporation experiments in order to understand and to study the behavior of the dryer wall temperature and the evaporation rate. All these analysis will contribute to future works involving the implementation of control strategies in the pastes and suspensions drying. The results obtained in transient analysis were compared with experimental data indicating that this model well represents the process

Projeto e Operação em Escala Semi-Industrial de um Equipamento para Tratamento de Águas Produzidas na Indústria do Petróleo Utilizando Nova Tecnologia: misturador-decantador à inversão de fases - MDIF

The aim of this work is to use a new technology in the treatment of produced wastewaters from oil industry. An unit for treat produced waters called UTMDIF, was designed, installed and operated in an industrial plant for treatment of effluents from oil industry. This unit operates by means of the method of separation of phase inversion and can become a promising alternative to solve the problem of oil/water separation. This method constitutes the basis of the working of a new design of mixersettler of vertical configuration which occupies small surface area. The last characteristic becomes specially important when there is limitation on the lay-out of the plant, for example, over maritime platforms to explore oil. This equipment in a semi-industrial scale treats produced wastewaters contaminated with oil at low concentrations (ranging from 30 to 150 mg/L) and throughputs of 320 m3/d (47,4 m3 m-2 h-1). Good results were obtained in oil/water separation which leads to the necessary specification to discharge those wastewaters. Besides, the non dependence of the efficiency of separation in spite of the salinity of the medium becomes the equipment an attractive new technology to treat wastewaters containing oil at low concentrations

Estratégia de gestão ambiental baseada nos princípios da produção mais limpa : um estudo de caso focado no segmento da carcinicultura

The objective of this scientific article is to introduce the opportunities of implementation of cleaner production (CP) in a shrimp culture farm. The methodology used for this was exploratory research implemented in a production unit located in the Northeast Brazil. The scientific article approaches since generic aspects of the technique about the management to use water, energy and the effluent characterization of this productive activity. It discusses quantitative aspects, environmental questions and chances of P+L during the productive process phases. The results points to input economy in the form of feed, soil correctives, medicines, and energy applied to the process, which range from 4% to 27%, emphasizing the small profit should be viewed as a source of considerable environment return. The authors conclude for the adoption property of this technique in this agribusiness segment, point out to the management importance of the input dosage in the quality of the final effluent, besides the adoption of a physical-chemistry remediation mechanism to the residual of Sodium metabissulphite used in the process of shrimp caught

Avaliação do potencial fitorremediador da mamona (Ricinus communis L.) e girassol (Helianthus annuus L.) quanto à remoção de chumbo e tolueno em efluentes sintéticos.

The development of research that aim to reduce or even eliminate the environmental impacts provided by anthropogenic actions. One of these main action is the discard of industrial waste in the biotic compartments such as soil, water and air, gained more space in academic settings and in private. A technique of phytoremediation involving the use of plants (trees, shrubs, creepers and aquatic) and their associated microorganisms in order to remove, degrade or isolate toxic substances to the environment. This study aimed to evaluate the potential for phytoremediation of castor bean (Ricinus communis L.) and sunflower (Helianthus annuus L.), wild crops suitable region of Rio Grande do Norte, to reduce concentrations of lead and toluene present in synthetic wastewater that simulate the characteristics of treated water production originated in the petrochemical Guamaré. The experiment was accomplished in randomized blocks in four replicates. Seeds of BRS Energy for the development of seedlings of castor beans and sunflower for Catissol 01, both provided by EMPARN (Empresa de Pesquisa Agropecuária do Rio Grande do Norte) were used. Lead concentrations tested were 250, 500 and 1000 mg/L called T2, T3 and T4, respectively, for toluene the concentrations used were 125, 256 and 501 μg/L, called T5, T6 and T7, respectively. The data for removal of lead in relation to sewage systems applied in castor bean and sunflower were 43.89 and 51.85% (T2), 73.60 and 73.74% (T3) and 85.66 and 87.80 % (T4), respectively, and toluene were approximately 52.12 and 25.54% (T5), 55.10 and 58.05% (T6) and 79.77 and 74.76% (T7) for castor and sunflower seeds, respectively. From the data obtained, it can be deduce that mechanisms involved in reducing the contaminants were of phytoextraction, in relation to lead and phytodegradation for toluene. However, it can be concluded that the castor bean and sunflower crops can be used in exhaust after-treatment of industrial effluents that have this type of contaminant

Variação da qualidade da água de chuva no início da precipitação

One of the most evident and actual concern, not only in the scientific means, but also of the public knowledge in general, is the lack problem of the potable water, that come increasing more each time, motivated mainly for the po llution of the sources, the bad use of the water and the increase of the population. In such a way, the necessity of looking for new water sources and the development of techniques to use sources minus explored is becoming even more important and urgent. T he rainwater comes being used since a long time like a supplying source, but, due the few knowledge of its characteristics, the generated preconception and the discrimination around its consumption and to the bad use of the technique of collection and stor age, it comes being little used, wasting consequently a significant parcel of this source. Trying to develop the knowing of some characteristics of the rainwater, the present work looks for to define the curve of variation of the quality of the rainwater i n three points with distinct characteristics of the city of Natal -RN, in the course of the precipitation, in some situations of time and space. For describe the curve of variation of the water s quality, some variables must be analyzed, and to be identifie d when they modify themselves in the endurance of rain, showing in which moment the purification of the water is more or less quickly. The pH, the Turbidity and the Electric Conductivity can be related with a big part of the physicist -chemistries variables found in the water and, like its analyses don't spend any material, they have easy access and measurement. The present work analyzes the curves of decline of these three variables, in three points with distinct characteristics in the city of Natal -RN, being these points: one next to the sea, another one in region with great buildings concentration and the last point in a less polluted area. For the studied region, it was during the five first millimeters of rain that occurs the biggest reduction of the exi sting impurities in the atmosphere, mainly between the first and the second millimeter, and after the five first millimeters the values of the variables stabilize. With exception of the University Campus, where initially the rainwater already has very good quality, the values of Turbidity and Electric Conductivity suffer a brusque reduction after the first millimeter of rain