Reconstrução e visualização de campos escalares 3D

-A necessidade de uma representação computacional cada vez mais fiel dos objetos do mundo real é inerente ao avanço das tecnologias computacionais na sociedade atual. Em especial, na computação gráfica, o objetivo é conseguir uma visualização que represente bem os modelos reais. Para que um objeto real seja representado graficamente, o ponto de partida seria a aquisição de dados do mesmo. A depender do resultado gráfico esperado, esses dados podem passar por uma serie de processamentos até que se obtenha um modelo a ser exibido. Muitas vezes, técnicas de modelagem geométrica não são suficientes para se gerar o modelo geométrico esperado. Isso porque podem esbarrar em uma série de empecilhos como: o alto tempo gasto em todo processo, a incoerência dos dados adquiridos, as inexatidões geradas por etapas manuais, etc. O surgimento e o avanço tecnológico dos dispositivos ópticos de obtenção de dados geométricos permitem uma amostragem de dados cada vez melhor de objetos reais. Porém, introduz-se um novo problema: como extrair das amostras boas representações de superfícies? A resposta a essa pergunta é a aplicação de técnicas de uma área de estudos dentro da computação gráfica: a reconstrução de superfícies. Campos escalares podem ser arbitrariamente complexos. Isso leva a uma grande preocupação quanto ao custo dos métodos e dos modelos finais destas aplicações. A conseqüência é que a otimização, concorrentemente às pesquisas de reconstrução, mostrou-se de grande importância e com grande diversidade de métodos para a realização da mesma. A otimização é comumente realizada sobre a malha resultante do processo de reconstrução. Após a reconstrução de um campo escalar, é necessário obter um modelo computacional eficiente e com grande grau de fidelidade ao modelo real. Este projeto se insere neste contexto. O objetivo é extrair informações a partir de campos escalares (superfícies ou volumes) e processá-los de forma que possa ser visualizado e analisado eficientemente. Esses processamentos envolveram o estudo de estruturas de dados eficientes, a otimização da malha que representa o modelo computacional. Essas operações precisam, não só manter a coerência, como ser feitas em um tempo hábil, devido à necessidade, por exemplo, de que estas sejam utilizadas em uma aplicação de tempo real. O principal resultado desta primeira parte do projeto é um conjunto de soluções para reconstrução de campos escalares e processamento de malhas. Para o desenvolvimento desta biblioteca, foi fundamental um estudo sobre vários conceitos importantes para que esta fosse consistente e atendesse a diversas aplicações. Foram utilizandos o método de Hoppe para reconstrução de superfícies e da teoria estelar na área de geometria computacional. A teoria estelar consiste no estudo da equivalência entre combinações de complexos simpliciais, ou seja, estuda uma classe de operações para editar uma malha sem alterar a sua topologia. Os resultados são basante satisfatórios no sentido de que foram abertas novas linhas de pesquisa. Entre elas podemos destacar a cooperação do GCG - Grupo de Computação Gráfica, Imagem e Visão com o Grupo da Física da Matéria Condensada na formulação de soluções para construção virtual de nanotubos de carbono e processamento de campos escalares contendo aglomerados de partículas. Além desses desdobramentos, esperam-se publicações importantes ainda em 2008

Evaluation of the relation between lean manufacturing, industry 4.0, and sustainability

Nowadays, Lean Manufacturing, Industry 4.0, and Sustainability are important concerns for the companies and in a general way for the society, principally, the influence of the two production philosophies, Lean Manufacturing and Industry 4.0, in the three main pillars of sustainability: economic, environmental, and social. According to the literature review done in this work, these relations are not well known and are dispersed by different sustainability’s criteria. To address this gap, this research proposes a structural equation model, with six hypotheses, to quantitatively measure the effects of Lean Manufacturing and Industry 4.0, in Sustainability. To statistically validate such hypotheses, we collected 252 valid questionnaires from industrial companies of Iberian Peninsula (Portugal and Spain). Results show that: (1) it is not conclusive that Lean Manufacturing is correlated with any of the sustainability pillars; and (2) Industry 4.0 shows a strong correlation with the three sustainability pillars. These results can contribute as an important decision support for the industrial companies and its stakeholders, even because not all the results are in line with other opinions and studies.This work has been supported by FCT - Fundação para a Ciência e Tecnologia within the Projects Scope: UID/CEC/00319/2019, and UID/615/2019. Moreover, the authors thank the 2100 Projects Association for the monetary support to develop this study, the three experts that contributed for survey validation, and also the enriching improvement suggestions of the Journal reviewers.info:eu-repo/semantics/publishedVersio

Análise da estabilização por solidificação de lodo de fosfatização em matrizes de cimento Portland e de cerâmica vermelha para a utilização na construção civil

O lodo de fosfatização gerado no tratamento de efluentes do processo de revestimento fosfático de aço é um resíduo sólido Classe IIA – Não Inerte, geralmente disposto em aterro industrial. Uma alternativa para o tratamento de resíduos é a estabilização por solidificação em matrizes cerâmicas e à base de cimento Portland. Isto permite a reciclagem do resíduo como matéria-prima para a construção civil, diminui os custos de tratamento e disposição final e reduz áreas de aterros. O presente estudo tem como objetivo verificar a estabilização por solidificação de lodo de fosfatização em matrizes de cerâmica vermelha, empregada na produção de blocos cerâmicos de alvenaria, e em concretos de cimento Portland. Foram realizadas caracterizações dos materiais envolvidos e ensaios de lixiviação e solubilização das matrizes estudadas com e sem a incorporação do lodo. Os resultados indicam que há uma tendência à estabilização por solidificação dos parâmetros avaliados tanto na matriz cerâmica quanto na matriz de cimento Portland

Reusing equipment in cells reconfiguration for a lean and sustainable production

Production cells are considered a flexible production system capable to face new market demands. In most cases, this is provided by their capability of reconfiguration, i.e., by removing/adding new equipment needed and/or reusing the existent equipment for the new demand. Nevertheless, some companies are not conveniently exploring this opportunity. What happened, many times, is the design of a complete new cell replacing all the equipment and sending the existent machinery to the warehouse. This is a decision that, economically and environmentally, is costly. Furthermore, knowing that some equipment could be reused for a new product. In a Lean Thinking, this is waste and a Lean company should promote a more efficient and sustainable production. This paper introduces a study in a Lean company that has developed practices to reuse equipment. The reasons for the non-reuse of the existent equipment were studied and some strategies were proposed to turn this equipment available and visible for reuse. Also, the benefits of reusing equipment related with saved costs and contribution to the environmental sustainability, are discussed.The authors acknowledge the company for allowing this study. This work has been supported by FCT – FundaXYo para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019

Lean and green – a systematic review of the state of the art literature

The move towards greener operations and products has forced companies to seek alternatives to balance efficiency gains and environmental friendliness in their operations and products. The exploration of the sequential or simultaneous deployment of lean and green initiatives is the results of this balancing action. However, the lean-green topic is relatively new, and it lacks of a clear and structured research definition. Thus, this paper’s main contribution is the offering of a systematic review of the existing literature on lean and green, aimed at providing guidance on the topic, uncovering gaps and inconsistencies in the literature, and finding new paths for research. The paper identifies and structures, through a concept map, six main research streams that comprise both conceptual and empirical research conducted within the context of various organisational functions and industrial sectors. Important issues for future research are then suggested in the form of research questions. The paper’s aim is to also contribute by stimulating scholars to further study this area in depth, which will lead to a better understanding of the compatibility and impact on organisational performance of lean and green initiatives. It also holds important implications for industrialists, who can develop a deeper and richer knowledge on lean and green to help them formulate more effective strategies for their deployment

A framework for the integration of green and lean six sigma for superior sustainability performance

Evidence suggests that Lean, Six Sigma and Green approaches make a positive contribution to the economic, social and environmental (i.e. sustainability) performance of organizations. However, evidence also suggests that organizations have found their integration and implementation challenging. The purpose of this research is therefore to present a framework that methodically guides companies through a five stages and sixteen steps process to effectively integrate and implement the Green, Lean and Six Sigma approaches to improve their sustainability performance. To achieve this, a critical review of the existing literature in the subject area was conducted to build a research gap, and subsequently develop the methodological framework proposed. The paper presents the results from the application of the proposed framework in four organizations with different sizes and operating in a diverse range of industries. The results showed that the integration of Lean Six Sigma and Green helped the organizations to averagely reduce their resources consumption from 20% to 40% and minimize the cost of energy and mass streams by 7-12%. The application of the framework should be gradual, the companies should assess their weaknesses and strengths, set priorities, and identify goals for successful implementation. This paper is one of the very first researches that presents a framework to integrate Green and Lean Six Sigma at a factory level, and hence offers the potential to be expanded to multiple factories or even supply chains

Green and lean sustainable development path in China: Guanxi, practices and performance

Globalisation has created both drivers and pressure for Chinese organisations to enhance their business performance as well as environmental performance. Green and lean practice is emerging as a critical approach for Chinese organisations to achieve sustainable development and improve organisational performance. By conducting empirical studies from 172 respondents on green and lean practice in different Chinese organisations, this research shows how green and lean practice affects organisational performance and how this association is affected by guanxi. The findings explain that guanxi between organisational partners improves the positive effect of green and lean practice on organisational performance. The results of this paper offer helpful insights into how managers should enhance their guanxi initiatives, in order to improve environmental and business performance over their supply chains. The paper also suggests the limitations of this research, as well as directions for future research

Primary problems associated with the health and welfare of employees observed when implementing lean manufacturing projects.

Lean philosophy is used by companies to increase productivity and reduce costs. Although uncontested benefits are created, it is necessary to highlight the problems related to employees' health and welfare caused by implementing lean manufacturing projects.The primary objective of this paper is to review the literature and identify the most relevant problems created by lean philosophy for employees.Research about the theme was performed on many international databases over three months, and an initial sample of 77 papers was found. Twenty-seven sources were utilized.We identified 22 categories of problems related to health and welfare of employees.The most cited problem was work intensification, mentioned by thirteen papers. Increased stress and increased responsibilities, demands and, consequently, pressure on the workers are among the primary problems observed in the research