62 research outputs found

    Multiple logistic regressions: controlling factors in applications to soil class prediction.

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    Métodos mais eficazes para determinação do padrão de distribuição de classes de solo na paisagem precisam ser avaliados visando suprir a demanda por mapas de solo em escalas regional e global. Neste estudo, Regressões Logísticas Múltiplas foram utilizadas como modelos preditores em uma aplicação de Mapeamento Digital de Solos. Os modelos foram gerados utilizando um mapa de solos existente como variável dependente e atributos de terreno como variáveis independentes, o que possibilitou determinar a probabilidade de encontrar classes de solo na paisagem no primeiro e no segundo nível categórico do SiBCS. A qualidade dos mapas preditos foi verificada por meio da matriz de contingência. A classe dos Argissolos foi predita corretamente, em relação ao mapa original, em aproximadamente 85 %. As classes de solos hidromórficos (Planossolos e Gleissolos) foram preditas corretamente em 75 %. Houve confundimento dos modelos para as classes que ocupam posições muito semelhantes na paisagem. Foi verificado também que classes de solo pouco representativas na paisagem não são adequadamente espacializadas em razão da sensibilidade dos modelos logísticos à proporção relativa das amostras usadas para treinar os modelos

    Overcoming barriers towards Sustainable Product-Service Systems in Small and Medium-sized enterprises: State of the art and a novel Decision Matrix

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    The Sustainable Product-Service Systems are a promising approach based on a Triple Bottom Line perspective of the sustainability. However, its practical and effective adoption is still very limited and addresses significant barriers for the manufacturing firms. Furthermore, this emergent topic has been discussed by literature mainly in large company's context, turning in a very limited and immature stage the current body of knowledge for the Small and Medium-sized Enterprises (SMEs). Thus, considering the significance of small companies to the global economy and their intrinsic difficulties, the purpose of this study was to identify the main barriers involving the transition towards Sustainable Product-Service Systems in manufacturing Small and Medium-sized Enterprises as well as the strategies to overcome them. A systematic literature review of the past two decades was organized capturing the state of the art of the area. Findings reveal that internal barriers associated with intrinsic characteristics of SMEs become still more sensitive during the transition (e.g., limited financial resources, the lack of competences, follower mentality and resistance to change). As well as, barriers related with the novelty of Sustainable Product-Service Systems models require new attitudes to small companies (e.g., changing mindsets from product ownership to use, replacing the value of exchange by value in use involving long-term relations, understanding the Product-Service Systems concept) and particularly highlight the lack of models/methods supporting this transition. The practical contribution of this study is in organise a comprehensive body of knowledge on strategies to overcome barriers towards Sustainable Product-Service offering. Moreover, an innovative decision matrix supporting decision-makers during the Sustainable Product-Service System development was proposed from the literature review findings. (C) 2019 Elsevier Ltd. All rights reserved

    In‐plane shear strength of single‐lap co‐cured joints of self‐reinforced polyethylene composites

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    The present study introduces the analysis of single‐lap co‐cured joints of thermoplastic self‐reinforced composites made with reprocessed low‐density polyethylene (LDPE) and reinforced by ultra‐high‐molecular‐weight polyethylene (UHMWPE) fibers, along with a micromechanical analysis of its constituents. A set of optimal processing conditions for manufacturing these joints by hot‐press is proposed through a design of experiment using the response surface method to maximize their in‐plane shear strength by carrying tensile tests on co‐cured tapes. Optimal processing conditions were found at 1 bar, 115 °C, and 300 s, yielding joints with 6.88 MPa of shear strength. The shear failure is generally preceded by multiple debonding‐induced longitudinal cracks both inside and outside the joint due to accumulated transversal stress. This composite demonstrated to be an interesting structural material to be more widely applied in industry, possessing extremely elevated specific mechanical properties, progressive damage of co‐cured joints (thus avoiding unannounced catastrophic failures) and ultimate recyclability

    Mapeamento digital de classes de solos: características da abordagem brasileira.

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    O solo é cada vez mais reconhecido como tendo um importante papel nos ecossistemas, assim como para a produção de alimentos e regulação do clima global. Por esse motivo, a demanda por informações relevantes e atualizadas em solos é crescente. Pesquisadores em ciência do solo estão sendo demandados a gerar informações em diferentes resoluções espaciais e com qualidade associada dentro do que está sendo chamado de Mapeamento Digital de Solos (MDS). Devido ao crescente número de trabalhos relacionados ao MDS, faz-se necessário reunir e discutir as principais características dos estudos relacionados ao mapeamento digital de classes de solos no Brasil, o que irá possibilitar uma perspectiva mais ampla dos caminhos, além de nortear trabalhos e demandas futuras. O mapeamento de classes de solos empregando técnicas de MDS é recente no país, com a primeira publicação em 2006. Entre as funções preditivas utilizadas, predomina o emprego da técnica de regressões logísticas. O fator de formação relevo foi empregado na totalidade dos estudos revisados. Quanto à avaliação da qualidade dos modelos preditivos, o emprego da matriz de erros e do índice kappa têm sido os procedimentos mais usuais. A consolidação dessa abordagem automatizada como ferramenta auxiliar ao mapeamento convencional passa pelo treinamento dos jovens pedólogos para a utilização de tecnologias da geoinformação e de ferramentas quantitativas dos aspectos de variabilidade do solo

    The effect of collaboration and IT competency on reverse logistics competency - Evidence from Brazilian supply chain executives

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    Business models have being designed, worldwide, to create sustainability competencies and in particular to incorporate reverse logistics, but Brazilian executives have not yet fully adhered to Law 12,305 on solid waste and reverse logistics. What would be the Brazilian executives' perception about reverse logistics competency and the support provided by a collaborative and IT competency? The objective of the paper is to investigate the effects of collaboration and IT competency in developing reverse logistics competency, as a strategy, and its consequences in economic and environmental performance. A survey was performed with 320 Brazilian supply chain executives and analyzed using Structural Equation Modeling. The models demonstrated that collaboration has a direct positive influence on the development of reverse logistics competency, by executives' point of view. The moderation effect between collaboration and IT competency for reverse logistics was not confirmed, since it was adopted a strategic view of reverse logistics. Therefore, despite there was not a moderation effect, IT presented a lower direct effect on reverse logistics competency. Results reinforce that organizations that develop reverse logistics competency tend to improve their economic and environmental performances.info:eu-repo/semantics/publishedVersio

    Los caminhos de la calidad, un estudio sobre la visión de expertos y productores rurales a respeto de procesos y tecnologías.

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    The production of special coffees consists of an art, employing different management and production and processing systems, to obtain the most advantageous results regarding final product quality. Several factors interact during the production cycle being, almost always, essential to obtain a product with better quality or, on the other hand, for its deterioration. This work aims to study and quantify the perception of the degree of importance of various forms and methods for the production of special coffees, from producers and experts, in the mountain regions of Espírito Santo. As methodology to understand the processes adopted by producers and indicated by experts, we used a questionnaire with closed questions, being the questionnaire validated by Cronbach's Alpha. After instrument validation, data were analyzed by t test, for analysis and comparison of the studied groups. The results indicate that some processes have no homogeneity between experts and producers of special coffees, indicating gaps which need to be better understood and studied. The harvest, wet processing, storage and technical assistance constructs were more homogeneous among the studied group, indicating that various techniques are rooted between experts and producers of special coffees

    Sedimentary Basin Water and Energy Storage: A Low Environmental Impact Option for the Bananal Basin

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    Groundwater storage is an important water management solution that is overlooked by several countries worldwide. This paper evaluates the potential for storing water in the Bananal sedimentary basin and proposes the construction of canals to reduce sediment obstructions in the river flow and harmful flood events. This would allow for better control of the water level. The water stored in the sedimentary basin can be used as a climate change adaptation measure to ensure that the level of the flood plain is maintained high during a drought or low during an intense flood event. Additionally, the flood plain will function as a water reservoir, regulate the river flow downstream from the flood plain, and enhance hydropower generation. A significantly smaller reservoir area is expected to store water, as the water will be stored as groundwater in the sedimentary basin. Results show that the Bananal basin has the potential to store up to 49 km3 of water, which can add up to 11.7 TWh of energy storage to the Brazilian energy matrix for a CAPEX energy storage cost of 0.095 USD/kWh. This is an interesting solution for the Araguaia basin and several other basins worldwide

    Sedimentary Basin Water and Energy Storage: A Low Environmental Impact Option for the Bananal Basin

    Get PDF
    Groundwater storage is an important water management solution that is overlooked by several countries worldwide. This paper evaluates the potential for storing water in the Bananal sedimentary basin and proposes the construction of canals to reduce sediment obstructions in the river flow and harmful flood events. This would allow for better control of the water level. The water stored in the sedimentary basin can be used as a climate change adaptation measure to ensure that the level of the flood plain is maintained high during a drought or low during an intense flood event. Additionally, the flood plain will function as a water reservoir, regulate the river flow downstream from the flood plain, and enhance hydropower generation. A significantly smaller reservoir area is expected to store water, as the water will be stored as groundwater in the sedimentary basin. Results show that the Bananal basin has the potential to store up to 49 km3 of water, which can add up to 11.7 TWh of energy storage to the Brazilian energy matrix for a CAPEX energy storage cost of 0.095 USD/kWh. This is an interesting solution for the Araguaia basin and several other basins worldwide
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