Modelagem e simulação numérica de um sistema de refrigeração por absorção utilizando o par H2O-LiBr

The term refrigeration solar refers to any air conditioning system that uses solar energy as a primary energy source. The use of solar radiation for cooling purposes is divided according to their technological possibilities which are distinguished from one another as the way that energy is involved in the cycle, work or heat. The first case is related to vapor compression cycles, in which the work input is provided by the photovoltaic conversion of solar energy into electrical energy. In the second case, an absorption refrigeration cycle is used and the thermal energy collected from the solar radiation is provided at the generator of this cycle.. In this work a system with an absorption cycle using the pair BrLi-water, using solar energy as input is modeled. It is considered a simple refrigeration cycle whose the equations of mass and energy conservation in each component are developed in order to obtain an algebraic equation set and a simulation routine using the EES software. Although the simulation operates under certain specified thermal load it is possible to estimate the necessary areas of heat exchangers and solar collectors

Pós-processamento de formas de ondas oriundas de descargas atmosféricas no Centro de Estudos de Descargas Atmosféricas e Alta Tensão (CENDAT) – IEE/USP

Atmospheric Discharges are responsible for several lost in the electrical system therefore it´s done studies to find ways to reduce the problem caused by discharges. This branch of engineering is necessary the gathering, stock and analysis of large quantity of data to validate or refuse the many studies produced about it The CENDAT proposed a project to collect data on induced voltages in distribution lines and current waveform of the lightning, but a difficulty that arose was the accumulation of data due to lack of manpower available to catalog all the data collected. Thinking in this difficulty, the engineer Acacio Silva Neto CENDAT´s researcher with trainees began to develop a program to solve this problem. This work keeps the development of this program in order to solve the problem of accumulation of data

Órtese de tornozelo: efeito sobre a razão de pico torque muscular eversor excêntrico/inversor concêntrico do tornozelo durante simulação do basquetebol

The ankle sprains represent the most common injuries in sports and basketball. In this sense, the use of ankle bracing and strength capacity analysis of the ankle evertor and invertor muscles, have been suggested as preventive measures and important tools for identifying risk factors associated with ankle sprains. However, questions still persist as to effect of the use ankle bracing on biomechanical variables related to the stability of the ankle. For this reason, this study aims to analyze the effect of the use of ankle bracing on peak torque (PT) of ankle evertor and invertor muscles and on eccentric evertor/concentric invertor torque ratio (EVEECC/INVCON), during the basketball match-play simulation. Ten healthy college basketball players, without mechanics or functional ankle instability performed a laboratory-based protocol representative of work rates observed during basketball match-play, in two different situations, with and without use of ankle bracing. The test was composed of a succession of intermittent physical effort equally distributed in four periods of 10 minutes each, considering the mechanical and physiological demands of a basketball match-play. Prior to the start of the trial (Evaluation 1) and after 2° (Evaluation 2) and 4° (Evaluation 3) periods, the subjects performed five maximal isokinetic concentric and eccentric contractions of ankle invertor and evertor muscles, separated by two minutes rest, at 60 °/s and 120 °/s. After testing for normality of data distribution with the Shapiro-Wilk test, was used the ANOVA repeated measures for two factors and post-hoc Bonferroni test for comparison of variables between assessments. Was adopted p < 0.05. There was no significant difference for PT and EVEECC/INVCON torque ratio between assessments. There was a decrease in PT EVEECC at 60º/s and 120º/s for the ...(Complete abstract click electronic access below)

Concepção e simulação de uma chaminé solar

The present work intends to study some fluid dynamic and heat transfer aspects of a solar chimney, aiming at a preliminary design of a facility. Some definitions and concepts of this system are presented. The simulation was performed based on a theoretical model validated with measurements of a prototype in Manzanares, Spain. Using the same theoretical model and some considerations, dimensions on a small scale are applied, making the model more interesting from its constructive aspect. The results show the behavior of the air velocity inside the chimney and illustrate some values of two preselected turbines. This technology looks promising in Brazilian territory due to high levels of solar radiation

Caracterização e origem da composição química da incrustação e simulação de cenários de perda de energia em setor da rede de abastecimento de água da cidade de Rio Claro - SP

The purpose of this work was the inlay’s characterization from the water supply networks of Rio Claro-SP city; as well analyze the influence of network’s aging in the actual system. To do this, some samples of inlays were collected and made chemistry analysis and X-Ray Diffraction Spectrometry. The history of the source water quality was also analyzed, to make possible to known the origins of the inlays. To evaluate the performance of the network, some different scenarios have been simulated, varying the resistance coefficient of the water supply networks of Rio Claro-SP. The characterization results showed that there are basically oxide and hydroxide of iron (magnetite and goethite) and quartz in the inlays, which are materials of high hardness. The hydraulic simulations indicated that the simulated scenarios had a variation of ~2000% in terms of loss of energy

Parametrização de modelo para simulação de distribuição de combustíveis em um terminal

A great competition between companies happens nowadays, due to, among other factors, the globalized economic system, the growing consumer demand and the technological advances. This fact implies the need for fast and efficient tools in decision making. A validated simulation model is able to perform this task. Thus, it was parameterized a simulation model of a fuel distribution terminal. It is a complex system because of its great variability. The model´s data input were collected, however the model was not statistically validated, in other word, does not adequately represent the real system. A search was made for the possible causes of this fact: dividing the compartments of tanker trucks, data collection may have been insufficient, inefficient model for unloading of biofuels

Análise comparativa de softwares de simulação de onda de cheia e corridas de massa

This scientific research aimed at presenting a comparative analysis of softwares used to represent the processes of flood wave and debris flow. For this, a literature review was performed on these processes and on simulation models used to represent them. Then, a research on scientific database and developers’ websites was performed to identify the softwares used to simulate these processes. This step was performed based on specific criteria such as the type of simulation performed by the software, its practical applications and a user friendly interface. A free distribution and totally functional software was chosen and its simulation mechanisms were tested through a simulation exercise and the results interpreted based on data on measured in the Basin of Ribeirão Marins section Monjolinho located in Piracicaba - SP. With respect to the processes, it was sought to present the dynamics, constraints, parameters and variables used to understand them and for the simulation models were presented the conceptual aspects of mathematical modeling including the steps of the simulation process and the different types of simulation models used to represent them. In total, 20 softwares were identified, and the software object of analysis was the ABC 6 that performs simulation of flood wave. Through the simulation exercise, it was observed that were presented overestimated values of flow compared to measured data in the basin. For both hypotheses were raised about the causes of the discrepancy between the observed and simulated flow. It has been concluded that the simulation process consisted of a complex procedure where generalizations, misrepresentations and simplifications may occur due to the data used and the method adopted, but it is a useful tool in planning and decision making in various types of studies and environmental projects

Projeto de um dispositivo para prensar bobinas polares de pólos salientes para hidrogeradores

The increasing demand for productivity and quality in companies has converged to a common point: reducing costs. In this context the present work aims at the development of a mechanical press which is designed for pressing polar hydrogenerators coils with salient pole in field facilitating the assembly of the poles in the plant, as well as reforms especially in hydrogenerators, reducing significantly the transport costs. With security in mind as well as reduced costs, a study was made of the materials to be used as it was applied a methodology for calculating the correct choice of safety factor to be used in the device. Through mechanical calculations were dimensioned critical items of the device as the diameter of the rods as well as the minimum thickness of the base of the device must have so that it does not break threaded shear in the region by applying the total load of traction on the risers implementation of the pressing. All compression loading device will be through the application of torque on the nuts of bolts in this way was defined by calculations the required torque for each nut so that you can reach the pressure specified in the design specifies. The modeling of the device was made using the INVENTOR™ program in conjunction with the program ANSYS ™. These programs have created designs in three dimensions, assembly and simulation of stress analysis in components of the device

Avaliação das condições de contorno da teoria de Hertz, comparando os resultados analíticos e numéricos a partir de simulações em software de elementos finitos

The objective of this study was to present the comparison between analytical and numerical results trying to identify the differences and behaviors of the variation of the principal stresses and the maximum contact pressure for different model configurations. The analytical equations of the theory of Hertz from the boundary conditions adopted by him were differences are shown. A step-by-step of developing the model indicating the geometric dimensions, surface contact, type of contact, the formulation used by the software, type of mesh, as well as the boundary conditions and load was presented. In the results, the stresses calculated analytically and compared with the stresses obtained by the finite element simulation software indicating the changes have been made

Ajuste do modelo QUAL2K e simulação de cenários para o Ribeirão Claro

The project has as objective to adjust the model QUAL2K to “Ribeirão Claro” river to evaluate the behavior of OD and DBO when are simulated the following sceneries: (i) implantation of a hypothetic wastewater station treatment that treats all the effluent thrown nowadays in the body of water; (ii) increase of withdrawal flow of DAAE to public supply and (iii) increase of nowadays flow of wastewater throwing, being the two last caused for the population increasing. The results obtained allowed to conclude that the model QUAL2K presented a good adjustment to the variable OD and a reasonable adjustment to the variable DBO, being that the same was suitable to the simulation of the sceneries proposed.

Simulação numérica de fluxo de águas subterrâneas na bacia do Rio Grande (BA)

The Urucuia Aquifer System represents a strategic water source in western Bahia. Its baseflow is responsible for the flow rate of the main tributaries of São Francisco river left bank in the dry season, including the Rio Grande, its main tributary in Bahia state. This river has a hydrological regime heavily affected by groundwater and is located in a region with conflicts about water resources. The aquifers geology is constituted by neocretacious sandstones of Urucuia Group subdivided in Posse Formation and Serra das Araras Formation. The embasement is formed by neoproterozoic rocks of Bambuí Group. This work focuses on an important tool application, the mathematical model, whose function is represent approximately and suitably the reality so that can assist in different scenarios simulations and make predictions. Many studies developed in this basin provided the conceptual model basis including a full free aquifer, lithological and hydraulical homogeneity in entire basin, null flux at plateau borders and aquifer base. The finite element method is the numerical method used and FEFLOW the computational algorithm. The simulated area was discretized in a single layer with 27.357,6 km² (314.432 elements and 320.452 nodes) totaling a 4.249,89 km³ volume. Were utilized 21 observation wells from CERB to calibrate the model. The terrain topography was obtained by SRTM data and the impermeable base was generated by interpolation of descriptive profiles from wells and electric vertical drilling from previous studies. Works in this area obtained mean recharge rates varying approximately from 20% to 25% of average precipitation, thus the values of model recharge zones varying in this range. Were distributed 4 hydraulic conductivity zones: (K1) west zone with K=6x10-5 m/s; (K2) center-east zone with K=3x10-4 m/s; (K3) far east zone with K=5x10-4 m/s; e (K4) east-north zone with K=1x10-5 m/s. Thereby was incorporated to the final conceptual model...

A simulação de Monte Carlo como instrumento fundamental para a análise de viabilidade econômica: a implementação de uma fundição de ferro em uma empresa metalúrgica

In uncertainly economic scenarios, an economic feasibility analysis must be done to accept a project based on investment criteria, such as NPV and IRR, mainly because the shareholders tend to invest their budget in a project if it has a great chance to return their investments. The studied company outsources all of its foundry services, what makes it very dependent of its suppliers, because the products have a lower quality level, long delivery periods and high prices. Therefore, this work will analyze the project of building an iron-casting foundry to decrease the dependence of its suppliers. In order to develop this research, all needed data related to the construction of the foundry and sales were collected to create deterministic and probabilistic (Monte Carlo Simulation) cash flows using MsExcel® and Oracle's Crystal Ball® software. As a result, the project was found to be risky by the NPV and IRR in the case of this new production line supplying only the internal needs. However, when the company offers its services to the foundry market, the project turns to be feasible

Simulação do tempo de descarga de caminhões graneleiros em uma estação de transbordo de carga em Porto Murtinho, MS

In the current decade, inter modal transport is widely discussed. In Brazil road transport is used in excess whereas there could be more focus and investment towards water transport. Water transport presents many benefits like being low cost and low maintenance. Sea and river ports today aren't capable of supporting Brazil's transport needs. Therefore, with this obstacle, this paper consists of an attempt of modeling and simulation of the process of unloading grain cargo from trucks, through simulation with ProModel software, to verify the necessity of installing more tumblers at the cargo unloading station in Porto Murtinho, MS

Estudo da fluência dos aços inoxidáveis ferríticos estabilizados ao titânio e nióbio e simulação numérica do processo no abaqus

The purpose of this research was tested a finite element model (FEM) that represented the creep of a slab during the reheating process of hot rolling. The aim is to prevent creep phenomenon changing the reheating profile with hot tensile test in Gleeble 3500, and, also, understand the former defect crisis. The goal of this work is to have a predictive tool to optimize the reheating process changing parameters (length and thickness). Then, use input parameters obtained from the tests to approximate the solution of the problem aided by Abaqus CAE. The results have showed that the ferritic stainless steel AISI 409 has a lower sensitivity to creep comparing to the stainless steel AISI 409, AISI 430Ti, AISI 441 and AISI 444

Estudo de melhorias dos painéis de baixa tensão da Faculdade de Engenharia de Guaratinguetá - UNESP

The protection and distribution systems for the electrics equipments are really important for the safety of products, process and final users, for an enterprise or even for a residence. For that, it’s necessary the utilization of low voltage switchboards for controlling the feeding of a charge, avoiding any kind of abnormality that can eventually occur. It’s necessary to pay attention in the cubicles conditions, and always verify if they are in accordance to the norms of the product, verifying also any kind of physical damage for the operator and/or users. In this line, the present graduation work analyses the low voltage switchboards in the college, checking if they are attending the actual standards, suggesting some improvements and later making a simulation of the creation of a new panel that reach all the needing in substitution of this actual, through the software Simaris. Using the research and lecture of norms and regulations for verifying the problems, this way we could register the greatest acting failures. These actions are made for becoming aware to the university about the danger in using electrics equipments without a minimum degree of protection, allowed by the law, and attempting to the urgency in changing this fails