Application of Design of experiments on the simulation of a process in an automotive industry

The objective of this article is to apply the Design of experiments technique along with the Discrete Events Simulation technique in an automotive process. The benefits of the design of experiments in simulation include the possibility to improve the performance in the simulation process, avoiding trial and error to seek solutions. The methodology of the conjoint use of Design of Experiments and Computer Simulation is presented to assess the effects of the variables and its interactions involved in the process. In this paper, the efficacy of the use of process mapping and design of experiments on the phases of conception and analysis are confirmed. © 2007 IEEE.

Improving a process in a brazilian automotive plant applying process mapping, Design of Experiments and Discrete Events Simulation

The objective of this article is to apply the Design of Experiments technique along with the Discrete Events Simulation technique in an automotive process. The benefits of the design of experiments in simulation include the possibility to improve the performance in the simulation process, avoiding trial and error to seek solutions. The methodology of the conjoint use of Design of Experiments and Computer Simulation is presented to assess the effects of the variables and its interactions involved in the process. In this paper, the efficacy of the use of process mapping and design of experiments on the phases of conception and analysis are confirmed.

Estimation of population profiles of two strains of the fly Megaselia scalaris (Diptera: Phoridae) by bootstrap simulation

A partir de perfis populacionais experimentais de linhagens do díptero forídeo Megaselia scalaris, foi determinado o número mínimo de perfis amostrais que devem ser repetidos, via processo de simulação bootstrap, para se ter uma estimativa confiável do perfil médio populacional e apresentar estimativas do erro-padrão como medida da precisão das simulações realizadas. Os dados originais são provenientes de populações experimentais fundadas com as linhagens SR e R4, com três réplicas cada, e que foram mantidas por 33 semanas pela técnica da transferência seriada em câmara de temperatura constante (25 ± 1,0ºC). A variável usada foi tamanho populacional e o modelo adotado para cada perfíl foi o de um processo estocástico estacionário. Por meio das simulações, os perfis de três populações experimentais foram amplificados, determinando-se, dessa forma, o tamanho mínimo de amostra. Fixado o tamanho de amostra, simulações bootstrap foram realizadas para construção de intervalos de confiança e comparação dos perfis médios populacionais das duas linhagens. Os resultados mostram que com o tamanho de amostra igual a 50 inicia-se o processo de estabilização dos valores médios.

Determinação de caminhos k-críticos em redes PERT

Neste trabalho, apresenta-se um estudo sobre os principais métodos para identificar os caminhos de maior duração em redes PERT, denominados na literatura de caminhos k-críticos (quando k = 1, tem-se o caminho mais longo, conhecido tradicionalmente por caminho crítico; quando k = 2, tem-se o segundo caminho mais longo, e assim sucessivamente). São discutidos três algoritmos apresentados na literatura e propõe-se um novo procedimento, denominado algoritmo da folga mínima, que apresenta algumas vantagens sobre os anteriores. O comportamento do algoritmo da folga mínima, quando aplicado a redes PERT, é verificado por meio de simulação.

A new three-phase transformer modeling for three-phase harmonic analysis in distribution systems

This work presents a new three-phase transformer modeling suitable for simulations in Pspice environment, which until now represents the electrical characteristics of a real transformer. It is proposed the model comparison to a three-phase transformer modeling present in EMTP - ATP program, which includes the electrical and magnetic characteristics. In addition, a set including non-linear loads and a real three-phase transformer was prepared in order to compare and validate the results of this new proposed model. The three-phase Pspice transformer modeling, different from the conventional one using inductance coupling, is remarkable for its simplicity and ease in simulation process, since it uses available voltage and current sources present in Pspice program, enabling simulations of three-phase network system including the most common configuration, three wires in the primary side and four wires in the secondary side (three-phases and neutral). Finally, the proposed modeling becomes a powerful tool for three-phase network simulations due to its simplicity and accuracy, able to simulate and analyze harmonic flow in three-phase systems under balanced and unbalanced conditions.

Desenvolvimento de um sistema para análise da estabilidade transitória de sistemas de energia elétrica via redes neurais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Eficiência de estimadores, geradores e algoritmos na simulação de dados diários de precipitação pluviométrica utilizando a distribuição gama

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Uso de modelos lineares mistos na avaliação genética de escores visuais: estudo de simulação

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

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

Continuous pasteurization of egg yolk: Thermophysical properties and process simulation

This article presents empirical correlations to predict the density, specific heat, thermal conductivity and rheological power-law parameters of liquid egg yolk over a temperature range compatible with its industrial thermal processing (0-61 C). Moreover, a mathematical model for a pasteurizer that takes into account the spatial variation of the overall heat transfer coefficient throughout the plate heat exchanger is presented, as are two of its simplified forms. The obtained correlations of thermophysical properties are applied for the simulation of the egg yolk pasteurization, and the obtained temperature profiles are used for evaluating the extent of thermal inactivation. A detailed simulation example shows that there is a considerable deviation between the designed level of heat treatment and that this is predicted through process simulation. It is shown that a reliable mathematical model, combined with specialized thermophysical property correlations, provide a more accurate design of the pasteurization equipment that ensures effective inactivation, while preserving nutritional and sensorial characteristics.

Numerical simulation of the liquid phase in SnO2 thin film deposition by sol-gel-dip-coating

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

MIGRATION MEASUREMENTS FROM PLASTIC PACKAGING: A SIMULATION STUDY ON INFLUENCE OF INITIAL CONCENTRATION PROFILE

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Numerical simulation of magnetic field enhanced plasma immersion ion implantation

The behavior of plasma and sheath characteristics under the action of an applied magnetic field is important in many applications including plasma probes and material processing. Plasma immersion ion implantation (PIII) has been developed as a fast and efficient surface modification technique of complex shaped three-dimensional objects. The PIII process relies on the acceleration of ions across a high-voltage plasma sheath that develops around the target. Recent studies have shown that the sheath dynamics is significantly affected by an external magnetic field. In this work we describe a two-dimensional computer simulation of magnetic field enhanced plasma immersion implantation system. Negative bias voltage is applied to a cylindrical target located on the axis of a grounded cylindrical vacuum chamber filled with uniform nitrogen plasma. An axial magnetic field is created by a solenoid installed inside the cylindrical target. The computer code employs the Monte Carlo method for collision of electrons and neutrals in the plasma and a particle-in-cell (PIC) algorithm for simulating the movement of charged particles in the electromagnetic field. Secondary electron emission from the target subjected to ion bombardment is also included. It is found that a high-density plasma region is formed around the cylindrical target due to the intense background gas ionization by the magnetized electrons drifting in the crossed ExB fields. An increase of implantation current density in front of high density plasma region is observed. (C) 2007 Elsevier B.V. All rights reserved.

Investigation of Plasma Immersion Ion Implantation Process in Magnetic Mirror Geometry

Plasma immersion ion implantation (PIII) with low external magnetic field has been investigated both numerically and experimentally. The static magnetic field considered is essentially nonuniform and is generated by two magnetic coils installed outside the vacuum chamber. Experiments have been conducted to investigate the effect of two of the most important PIII parameters: target voltage and gas pressure. In that context, it was found that the current density increased when the external parameters were varied. Later, the PIII process was analyzed numerically using the 2.5-D computer code KARAT. The numerical results show that the system of crossed E x B fields enhances the PIII process. The simulation showed an increase of the plasma density around the target under the operating and design conditions considered. Consequently, an increase of the ion current density on the target was observed. All these results are explained through the mechanism of gas ionization by collisions with electrons drifting in crossed E x B fields.

Low voltage four-quadrant current multiplier: An improved topology for n-well CMOS process

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)