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In this work, we consider the practical issues of resource allocation problem in OFDMA two-way relay networks: the inaccuracy of channel-state information (CSI) available to the transmitters. Instead, only the estimated channel status is known by the transmitters. In this context, a joint optimization of subcarrier pairing and allocation, relay selection and transmit power allocation is formulated in the OFDMA two-way amplify-and-forward relay networks. Moreover, to ensure the Quality of Service (QoS) requirement, the energy consumption must be minimized without compromising the QoS. Therefore, by applying convex optimization techniques, energy efficient algorithms are developed with the objective to minimize the total transmit power while guaranteeing the required data rates. Through simulation studies, energy consumption performance of the systems under the proposed schemes are investigated. It is shown that the proposed scheme can improve the energy consumption performance without scarifying the QoS.

Abstract The relationship between fuel consumption in a multi-storey block of flats and climatic exposure is investigated. Fuel consumption anomalies between identical flats are attributed to vagaries in the airflow around the building and highlight the need for improved standards of thermal insulation and/or differential thermal insulation, dependent upon flat location. Climate and building design and the subject of building Climatology in architectural education are discussed briefly.

Constructed in 1986, the Biosphere 2 Test Module has been used since the end of that year for closed ecological systems experiments. It is the largest closed ecological facility ever built, with a sealed variable volume of some 480 cubic meters. It is built with a skin of steel spaceframes with double-laminated glass panels admitting about 65 percent Photosynthetically Active Radiation (PAR). The floor is of welded steel and there is an underground atmospheric connection via an air duct to a variable volume chamber ("lung") permitting expansion and contraction of the Test Module's air volume caused by changes in temperature and barometric pressure, which causes a slight positive pressure from inside the closed system to the outside thereby insuring that the very small leakage rate is outward. Several series of closed ecological system investigations have been carried out in this facility. One series of experiments investigated the dynamics of higher plants and associated soils with the atmosphere under varying light and temperature conditions. Another series of experiments included one human in the closed system for three, five and twenty-one days. During these experiments the Test Module had subsystems which completely recycled its water and atmosphere; all the human dietary needs were produced within the facility, and all wastes were recycled using a marsh plant/microbe system. Other experiments have examined the capability of individual component systems used, such as the soil bed reactors, to eliminate experimentally introduced trace gases. Analytic systems developed for these experiments include continuous monitors of eleven atmospheric gases in addition to the complete gas chromatography mass spectrometry (GCMS) examinations of potable, waste system and irrigation water quality.

The design of the facility is described in terms of its use as an investigation tool for evaluating crop growth in space with reference to required emerging technologies. NASA's CELSS Test Facility (CTF) is designed to permit the measurement of crop-plant productivity under microgravity conditions including biomass production, food production, water transpiration, and O2/CO2 exchanges. Crucial hardware tests and qualifications are identified to assure the operation of CTF technologies in space including the nutrient-delivery, water-condensation, and gas-liquid-mixing subsystems. The design concept and related scientific requirements are described and shown to provide microgravity crop research. The CTF is expected to provide data for plant research and for concepts for bioregenerative life-support systems for applications to Martian, lunar, and space-station missions.

The global apparel and textile market has been changed considerably during the recent years. At the one hand, new trends and consumer preferences for different styles and fashion products emerge continuously, thus the apparel industry becomes more mass customized. On the other hand, attention to social and environmental sustainability has been dramatically increased in the entire industry. However, the current fast-changing fashion trends result to significant environmental and resource depletion problems in the textile lifecycle. As a result, the apparel industry should consider sustainable manufacturing strategies. The current options such as organic fibers and environmentally safe dyes seem promising. Nonetheless, there are significant challenges for apparel manufacturers and retailers to capitalize sustainability. To address these problems, in this paper, we develop a conceptual model of Social Manufacturing for the apparel industry. We study the current value chain of the apparel industry and identify its challenges from the sustainability's view. Then, we propose a new model to improve the sustainability throughout the value chain of the apparel industry.

Abstract China Three Gorges Corporation (CTGC) is China's largest clean energy company and one of the world's leading hydropower companies. In the process of building itself into a “world-class clean energy group”, the company is faced with such disadvantages as lack of project experience in the new energy industry, relative shortage of human resources, and shortage of technology reserves for the new energy industry. The company also faces threats from potential competitors in the clean energy industry, the international environment, seasonal constraints, capital markets and other factors. An enterprise development strategy assessment is needed. This paper uses the SWOT method to analyze the fit between the enterprise's current situation and development goals from six aspects, including opportunities, threats, advantages and disadvantages. A quantitative evaluation index system of internal environment and external environment factors is established, and the advantages and disadvantages of enterprise development environment are determined by constructing an evaluation matrix. The comprehensive study shows that in order to realize the vision of “becoming a first-class clean energy group”, the enterprise should change from the conservative progressive development mode to the expansive development strategy mode.

To satisfy the needs of a demanding and competitive market, Amtrol-Alfa decided to allocate its resources in a new innovative composite cylinder. The CoMet cylinder consists of a thin steel inner liner, wrapped in a commingled glass and polypropylene fibre inside a plastic jacket, which exceeded our expectations. Safety and environment are on the top of Amtrol-Alfa’s priorities. As such, the manufacturing of the CoMet cylinder has no dangerous emissions to the environment, in comparison with thermoset traditional processes, and uses inert products such as PP and HDPE. Regarding recyclability, the steel can be reprocessed, the commingled fibres can be chopped and used in injection processes, including the HDPE exterior jacket that can also be chopped and re-injected. The use of only recyclable products contributes to a better environment. The design was thoroughly studied, so that the handling is less aggressive to the costumer. The cylinder exterior is also very important, not only because the new design may look more ergonomic and elegant, but also because it is cleaner and safer. CoMet lightweight cylinder integrates in one cylinder, the Past and the Future, the Proven and the Innovation, in an elegant compromise.

Abstract An EHC (electrically heated catalyst) of a four stroke motorcycle engine with heat storing material was used to investigate the effect of input energy on the carbon monoxide (CO) conversion efficiency after cold start. The factors studied included the length of the heat storing material, heating temperature and pre-heating time. The stainless steel heat storing material was 15 mm wide and 0.3 mm deep and was installed at the inlet and mid-section of the catalyst. The settings of the parameters were heat storing material lengths of 30 and 60 cm, pre-heating time of 5, 15 and 25 s, a CO setting level of 1.3% and 1.8% and a heating temperature of 140, 180 and 220 °C. It was revealed that for the shorter heat storing material, better conversion efficiency was attained when heating at the inlet. Heating at the mid-section of the catalyst with the same length of heat storing material resulted in less energy stored, quicker heat dissipation and more frequent re-heating required. In contrast, with a longer heat storing material, the temperature rise was more gradual and more heat was absorbed, resulting in a more stable overall temperature development. It was further showed that under the same input energy, the shorter heat storing material provided a higher CO conversion efficiency than the longer material. Further, a threshold total input energy for achieving a CO conversion efficiency above 65% was found to be 100 kJ.

AbstractSolid‐state cooling is an environmentally friendly, no global warming potential alternative to vapor compression‐based systems. Elastocaloric cooling based on NiTi shape memory alloys exhibits excellent cooling capabilities. Due to the high specific latent heats activated by mechanical loading/unloading, large temperature changes can be generated in the material. The small required work input enables a high coefficient of performance. An overview of elastocaloric cooling from basic principles, such as elastocaloric cooling cycles, material characterization, modeling, and optimization, to the design of elastocaloric cooling devices is presented. Current work performed within the DFG (Deutsche Forschungsgemeinschaft) Priority Program SPP 1599 “Ferroic Cooling”, which is focused on the development and realization of a continuously operating elastocaloric cooling device, is highlighted. The cooling device operates in a rotatory mode with wires under tensile loading. The design allows maximization of cooling power by suitable wire diameter scaling as well as efficiency optimization by implementing a novel drive concept. Finally, computer‐aided design (CAD) models of the discussed solid‐state air cooling device are presented.