The modern lifestyle has resulted in a gradual dismantling of the vital services offered by nature, putting human existence at risk. In this sense, it is understood as a Public Administration responsibility the active participation in the promotion of sustainable consumption and production strategies, not only through public policies implementation, but also through its abundant purchasing power. Thus, the present investigation aims to identify and classify the main barriers that have hampered the massive application of sustainable public procurement (SPP) in Brazil. The proposed objective was achieved through a Delphi study. A panel of experts identified 32 main obstacles for SPP implementation, which were subsequently ranked according to a five-point Likert scale. The results suggest that, among all the barriers identified, 10 are the leading factors that hinder the implementation of SPPs in the Brazilian public sector. The findings of this paper, therefore, provide a valuable reference for experts and practitioners in the selection of the obstacles that must be firstly overcome to stimulate the application of SPPs.

Resumo O cenário atual é marcado por uma crescente necessidade de energia, esgotamento de recursos naturais e pela necessidade de se aumentar os cuidados com o consumo de energia do setor elétrico. Com o crescimento da demanda por energia, torna-se essencial a obtenção de maior eficiência energética. Para tal é fundamental não somente buscar soluções que produzam energia através de fontes limpas e renováveis, como também mitigar as perdas no sistema elétrico atual. Assim sendo, surge uma proposta de investigar a possibilidade de reestruturar os sistemas de iluminação, utilizando lâmpadas de LED, distribuídos em corrente contínua e abastecidos a partir de energia solar fotovoltaica. O presente artigo se insere nessa linha e apresenta a eficiência gerada pelos sistemas de iluminação constituídos por meio de lâmpadas de LED sem drivers de conversão e energia gerada através de painéis fotovoltaicos. A pesquisa mediu em laboratório as perdas e os ganhos em eficiência dessas lâmpadas de LED. Os resultados experimentais demonstraram ganho na eficiência energética das lâmpadas de LED sem o driver de conversão frente às lâmpadas com drivers. Com o dimensionamento do sistema solar fotovoltaico necessário para o sistema de iluminação, obteve-se o tempo de retorno do investimento.

Forecast models play a fundamental role in anticipating the effects of the energy demand in buildings to addressing the energy crisis. A forecast model for anticipating from one to three days every 30 min of the building energy demand is presented. In this model, a feed-forward artificial neural network (ANN) is combined with bootstrap aggregation techniques, using a Box-Cox transformation, seasonal and trend decomposition using loess, and a moving block bootstrap technique. An analysis was conducted using the data provided by a building's energy demand; the data were collected during a period of four months, with readings every 10 s and averages of the values obtained every 30 min. The feed-forward neural-network method combined with bootstrap aggregation techniques consistently outperformed the forecasting accuracy of the original feedforward neural network through cross-validation in the root mean square error (RMSE) and the mean absolute percentage error. From cross-validation in-sample period, used for the initial Original Research Article

Inspiration "We physicists can dream up and work out all the details of power reactors based on dozens of combinations of the essentials, but it is only a paper reactor until the metallurgist tells us whether it can be built and from what. Then only can one figure whether there is any hope that they can provide power."Dr. Norman Hilberry, former Director, Argonne National Laboratory Higher Temperature Reactor Materials Workshop March 18-21, 2002iii The goal of the Generation IV initiative is to make revolutionary improvements in nuclear energy system design in the areas of sustainability, economics, safety and reliability. The Generation IV Nuclear Energy Systems Roadmap working groups have identified operation at higher temperature as an important step in improving economic performance and providing a means for nuclear energy to support thermochemical production of hydrogen. However, the move to higher operating temperatures will require the development and qualification of advanced materials to perform in the more challenging environment. As part of the process of developing advanced materials for these reactor concepts, a fundamental understanding of materials behavior must be established and the data-base defining critical performance limitations of these materials under irradiation must be developed.This workshop reviewed potential reactor designs and operating regimes, potential materials for application in high-temperature reactor environments, anticipated degradation mechanisms, and research necessary to understand and develop reactor materials capable of satisfactory performance while subject to irradiation damage at high temperature. The workshop brought together experts from the reactor materials and fundamental materials science communities to identify research and development needs and opportunities to provide optimum high temperature nuclear energy system structural materials. Higher Temperature Reactor Materials Workshop March 18-21, 20022 Many materials R&D areas were identified to support development of Generation IV concepts.Based on the discussions at this workshop, the following areas appear to be the most critical for advancing Generation IV concepts.Research on advanced ferritic-martensitic and martensitic steels that allow for increased temperature of operation for liquid-metal and supercritical water concepts while improving toughness at lower temperatures. Issues include stability of oxides in ODS materials, basic microstructural and microchemical changes, and phase stability at high temperatures.Development and fundamental understanding of radiation performance of refractory alloys, ceramic composites, and coatings for high and very high temperature concepts.Research to improve radiation performance of austenitic stainless alloys including resistance to void swelling, embrittlement and stress corrosion cracking.Development of new high-temperature superalloys that are tailored for radiation environments (e.g., low nickel contents and controlled phase stability)Fundamental and applied un...

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