Gray Farias Moita

Experimental and numerical analysis of large ferrocement water tanks

Abstract In the current work the ferrocement construction technique is revisited with the purpose of applying the material in civil engineering structures, particularly in large water tanks for water treatment stations. Although it is not a new technology, ferrocement continues to be an attractive alternative. The plastic potential, the unsophisticated construction techniques and the low cost justify its use, especially suitable for developing countries. However, modelling studies of this material are rare in the literature; this is what justifies the studies currently being conducted to improve current practices of design, as well as to further advance the understanding of the material. This work describes experimental and numerical tests for large ferrocement tanks, part of the water treatment facility in Divinopolis, Brazil. Different finite element models have been used in the analyses in order to evaluate the effect of some adopted simplifications. Some comparisons of the investigated approaches with the experimental data are also included, as well as remarks on the use of different constitutive models, homogenisation techniques and accuracy of the modelling data.

Simulação da movimentação de pessoas em situações de emergência: aspectos ergonômicos e computacionais com autômatos Fuzzy e sua aplicação ao projeto arquitetônico

Este artigo apresenta o programa computacional Fuga, desenvolvido para simular a movimentacao de pessoas em ambientes construidos durante uma situacao de abandono. Esse programa se baseia na modelagem celular e possui como principais paradigmas a utilizacao de aspectos ergonomicos associados a movimentacao humana e a utilizacao da Logica Fuzzy como ferramenta de inteligencia computacional para emulacao do processo de tomada de decisao humana. Os aspectos ergonomicos e o processo de tomada de decisoes sao apresentados. E realizada uma validacao do modelo, assim como varias simulacoes, ilustrando como pode ser utilizado na concepcao de ambientes mais seguros, de uma forma que dificilmente seria obtida pela simples aplicacao das legislacoes vigentes.

Inspection technique for the validation of software development processes

Although, there are several software development processes with different characteristics in the literature, such processes are not enough to encompass the numerous fields of software applications. The practices of development differ among the developers and, sometimes, it is necessary to improve, customize or join processes already known to guarantee one needs. However, a process can only guarantee its correctness and efficiency after being thoroughly tested and validated. In the current work, a process validation model is proposed, based on the concepts of Verification and Validation (V&V), making use of the Software Inspection Technique to validate software development processes. It is presented a case study that was carried out as a first attempt of analysing the proposed model.

Simulation of People Flow by a New Fuzzy Discrete Automata Model and an Ergonomic Approach

This work presents the computer program FUGA v. 1.0, developed to simulate the movement of people in constructed environments in normal situations and also during an evacuation in emergency situations. FUGA is based on a discrete automata model using pre-defined rules. This program uses an ergonomic approach associated with human movement and fuzzy logic as a computer intelligence tool to emulate the human decision-making process. The model incorporates mechanical and mental aspects, as well as their quantitative and qualitative nature. This work shows how selected ergonomic quantities are incorporated into a human decision-making process emulated by a fuzzy logic system. FUGA simulates environments with any internal or external geometry; with one or more floors; with or without staircases or ramps and with uni or multi directional flows. Some simulations are performed showing how the software FUGA can be used in the design of safer environments, in a way that could hardly be achieved by simply applying the existing regulations.

Influence of fibre reinforced polymers in the rehabilitation of damaged masonry wallettes

In the past decade, the interest in repair and retrofitting of existing structures and rehabilitation of the damaged structures has led to the development of more effective and low invasive architectural and engineering strategies. In this aspect, the application of fibre reinforced polymer (FRP) strengthening techniques has become reasonably widespread as suitable solutions in addition to the traditional ones. They are promising techniques because of their key characteristics such as: high specific strength, high stiffness, small thickness compared to conventional materials, low influence on the global mass, little durability concerns, ease of handling, flexibility and fast installation that improve on-site productivity, and have a low impact on building functions. In this context, the use of carbon fibre reinforced polymers (CFRP) and glass fibre reinforced polymers (GFRP) for the rehabilitation of damaged small masonry walls (here called wallettes) was investigated experimentally. This study sought to measure the maximum loading carrying capacity of the wallettes and to assess the possible structural rehabilitation in the damaged masonry structures after their reinforcement with the composite polymers. For the adhesion between the wallettes and the reinforcement fibres, primer, putty and a saturant glue epoxy resins were used. Debonding between the FRP composites and the substrate has been recognized as the primary failure mechanism of this reinforcement system and it occurs when the system shear capacity is reached and the FRP is detached from the element. This phenomenon is also addressed in this paper. In general, the experimental results showed the recovery of the original compressive loading bearing capacity of the structures, in spite of the debonding of the FRP composites. Moreover, it could be observed an increasing of up to 39% and up to 49% of the compressive strength for the damaged masonry wallettes reinforced with CFRP and GFRP systems, respectively. The recover (or even rise) in the loading capacity of the reinforced structures due to the external fibres bonding is a good indication of their effectiveness in these situations.

Uma análise dos principais tópicos de pesquisas investigados pelos pesquisadores doutores brasileiros

The production and publication of scientific papers presented an impressive growth in the last decades, being the Internet the main factor of access and diffusion of these to the community. Given this context, there is a global interest in all areas of knowledge regarding studies of scientific production data, in order to know what has been done about science. The understanding of how the researches have evolved may serve as a basis to build scientific policies that accelerate the progress of science or to impel research groups to become more productive. In this context, the aim of this study is to analyze the research topics published during the last 55 years in the Brazilian Science trajectory of researchers with a doctoral degree, in order to map scientific knowledge and identify hot topics. For this, the general characterization and an analysis of data related to the keywords of the articles published in congresses annals and in periodicals are carried out, written by the researchers who have curricula registered in the Lattes Platform. The results showed an overview of the keywords used by the PhDs, and identification and analysis of the main research topics developed by them. Also the validity of the results from the quantitative point of view was verified, to help the understanding about the development of the Brazilian science.

Analysis of the evolution of institutional scientific collaborations of post-graduate teachers between the years of 2012 to 2015

The propagation and dissemination of knowledge are extremely important elements for the collaboration of the countrys scientific growth and development. One example is scientific collaboration networks, where interactions between two or more researchers occur, making it easier to share and perform tasks for a mutual purpose. The objective of this work is to analyze how the institutional scientific collaborations occur through the collaborative networks of the Brazilian research institutions throughout the last four years, and also to identify how these networks have become denser with the intensity of collaborations of researchers linked to these institutions. As a result, there was the characterization of graphs, graphics and tabular results of the Lattes Platform data network. It is concluded that the number of publications among researchers of the same institution is still relatively high and that the evolution of institutional scientific collaborations is increasing.

A text mining based strategy for understanding the process of orientation in scientific data repositories

Academic genealogy allows us to understand the guiding-oriented relationship, and to analyze how the knowledge diffuses through the counselor, especially in postgraduate programs, where most of the students intend to remain in the academic environment. Given this, this is an important means to analyze this relationship in several areas of knowledge. In this work, the data of orientations and supervisions coming from Lattes curricula related to the area of computer science are used, obtaining an overview of the genealogy of this group, and also, to produce genealogical trees, allowing to analyze how the knowledge has been propagated.

On the Boate Kiss Fire and the Brazilian Safety Legislation - What we can learn

Brazil was recently the scenario of a great tragedy in the fire at Kiss nightclub, where 242 people were killed. The starting point of the fire was the use of a pyrotechnic device over an acoustic coating made of polyurethane foam. The causalities were caused mainly by asphyxia and inhalation of toxic gases in a very fast smoke expansion. However, several additional causes contributed to the amount of damage and human losses. The accident investigations emphasized the necessity to discuss details in the applicable Brazilian legislation. In this work, the tragedy of Kiss nightclub is presented and the some of their mainly aspects discussed. The Brazilian standard (ABNT NBR 9077) to determine the dimension of emergency exits is also presented. Then, a computational simulation of evacuation process in an environment externally similar to Kiss nightclub with different width exits and populations is performed using the software Fuga. It was found that, in spite of the configurations of Kiss nightclub have had a fundamental role in tragedy, the current Brazilian standard was not appropriate for the design of such environment and should not have been used. Moreover, clear and more rigorous standards also need to be further discussed, particularly for panic situations. At the end, some considerations are made in order to improve the standards about the dimensioning of emergency exits.

Simulação com Lógica Fuzzy da Movimentação Bidirecional de Pessoas com Formação de Rios de Escoamento e do Empacotamento Humano

Durante a movimentacao de pessoas em uma situacao de abandono de um ambiente construido, normalmente, se imagina que o escape ira ocorrer em fluxo unidirecional rumo as saidas mais proximas. Mas em situacoes de grande estresse e desorientacao, o fluxo humano pode nao ser direcionado. Alem disso, mesmo numa situacao de normalidade, um fluxo bidirecional mal concebido pode causar uma perigosa situacao de congestionamento ou comportamento nao adaptativo. Dois dos importantes fenomenos que podem acontecer na movimentacao bidirecional sao a formacao dos rios de escoamento e do empacotamento. Na movimentacao humana, alem dos aspectos fisicos, devem tambem ser considerados os aspectos comportamentais e cognitivos das pessoas envolvidas, cuja natureza e basicamente qualitativa. Para que se possa realizar uma modelagem com fatores de natureza tao distinta, uma ferramenta de inteligencia computacional passivel de ser usada e a logica fuzzy. Assim, este trabalho tem como objetivo modelar qualitativamente a movimentacao humana em fluxos bidirecionais, observando a formacao dos rios de escoamento humano e do empacotamento, por meio de uma modelagem celular associada a logica fuzzy.