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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.

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.

The present study deals with the development of the principles and conditions of fish waste mineralization using the method of wet combustion with hydrogen peroxide in alternating electromagnetic field and describes testing mineralized human waste and fish waste as sources of nutrients for plants in the biotechnical human life support system (BTLSS). The study shows that mineralization of fish waste in the wet combustion reactor should be performed in the presence of readily oxidized organic matter, represented by human waste, as an activator of oxidation. Re-mineralization of the sediment in the mixture of hydrogen peroxide and nitric acid in the wet combustion reactor converts mineral elements bound in the sediment into the form available to plants. Using mineralized fish waste as an additional source of mineral elements in the nutrient solutions for growing plants based on mineralized human waste is a way to reduce the amounts of mineral elements added to the solution to replenish it, enabling fuller closure of material loops in the BTLSS.

In Advanced Life Support (ALS) systems with bioregenerative components, plant photosynthesis would be used to produce O2 and food, while removing CO2. Much of the plant biomass would be inedible and hence must be considered in waste management. This waste could be oxidized (e.g., incinerated or aerobically digested) to resupply CO2 to the plants, but this would not be needed unless the system were highly closed with regard to food. For example, in a partially closed system where some of the food is grown and some is imported, CO2 from oxidized waste when combined with crew and microbial respiration could exceed the CO2 removal capability of the plants. Moreover, it would consume some O2 produced from photosynthesis that could have been used by the crew. For partially closed systems it would be more appropriate to store or find other uses for the inedible biomass and excess carbon, such as generating soils or growing woody plants (e.g., dwarf fruit trees). Regardless of system closure, high harvest crops (i.e., crops with a high edible to total biomass ratio) would increase food production per unit area and O2 yields for systems where waste biomass is oxidized to recycle CO2. Such interlinking effects between the plants and waste treatment strategies point out the importance of oxidizing only that amount of waste needed to optimize system performance.

AbstractW. R. Butterworth reports on the performance and scientific base of a commercial operation which matches two problems: recycling urban ‘wastes’ and producing sustainable biofuels. The proximity recycling of ‘wastes’ to produce biofuels in a closed loop mimics the original processes in the Carboniferous Era which laid down the global fossilized fuel reserves. When urban wastes are composted and can substitute for mineral fertilizers, a crop will use the green leaf and photo synthesis to capture far more carbon dioxide than is released when the biofuel produced from the crop seed is finally burned to release the energy captured from the sun. Most of the captured carbon goes into a carbon sink in the soil from which it only slowly oxidizes and at predictable rates. The figures of carbon capture, oxygen release and food production are related to fuels produced. Published © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd

Abstract Water hammer is a transient flow phenomenon generated in a pipeline, when there is a sudden change in velocity, due to the closing of valves. This is particularly important for plants based on complicated hydraulic circuits and piping, to avoid malfunctioning in the urban sewer network. In this study, the effect of a set of parameters: length, diameter and material of the pipe with and without surge tank on transient pressure is investigated by using the software HAMMER V8i. The results show that the maximum Transient Pressure is strongly influenced by an increase of 41.24% of the pipe diameter when the Surge Tank is not present. When the surge tank is inserted the transient pressure increases only of about 12.2%. So the surge tank can have a positive influence on the entire network. Moreover, the increase in the length will lead to a decrease in the Total Pressure of about 10% without Surge Tank and of 8.62% with Surge Tank. While the change in the roughness coefficient of the material used for the pipes will cause a decrease in the Total Pressure of about 42.6%, without Surge tank, and of 12.2% with Surge Tank.

Nowadays the sustainability issues are trendy considering the environmental problems caused by an unbridled use of the resources. Governments are making efforts aiming to increase the industrial sensibility to environmental problems promoting actions to reduce the impact of their activities. The manufacturing technologies are involved in this scenario too. Electrical Discharge Machining (EDM) is a technology that finds a wide use in the micromachining sector for a variety of drilling applications in automotive, aerospace, biomedical sectors on different materials such as stainless steels, titanium alloys and others metals regardless of their mechanical properties. In this paper, a method to evaluate the sustainability of this process is proposed, taking into account the consumption of the electrical energy, the wear of the tool electrode during the machining, the consumption of the dielectric fluid, the environmental impact and part conformance. This method was applied for the drilling of a component in biomedical sector such as a bone plates in titanium alloy for fractures of small body parts. The micro holes were executed in different conditions as regards both electrode material and dielectric fluid. The sustainability of the machining was evaluated for all the tested conditions. In this way, the best operative conditions to minimize the environmental impact by using this technology were found. Moreover, the more critical aspects were identified. This allows targeted actions to be taken to diminish the impact of these aspects.