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1.
This paper investigates the scope for stabilizing commodity prices by buffer stock interventions. Optimal control is used, rather than simulation, to evaluate the scope for intervention at best. Applications to a world copper market model show that substantial but extensive gains to stabilization are possible. These gains cannot be realised by traditional bandwidth decision rules. An important difficulty is setting the level at which prices should be stabilized. The lack of this information severely reduces the achievable gains.  相似文献   
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Soy-polyol has been synthesized via a low energy two-step continuous route thus avoiding intermediate steps and chemicals. The functional groups of soy-polyol thus produced were identified by Fourier transform infrared (FTIR) spectroscopy which confirmed the cleavage of the double bonds, the formation of new epoxy linkages and the presence of hydroxyl groups. The change in chemical structure and physical properties of the soy polyol was further characterized and the results indicated a successful conversion with reduced unsaturation, increased hydroxyl number and increased viscosity. Polyurethane foam was prepared from soy-polyol using isocyanate and thermogravimetric analysis was used to study its thermal decomposition behaviour. Multiple transitions were identified in relation to depolymerization and bond dissociation. Density and compressive strength of the soy-foam were found to be satisfactory. An investigation of microstructure of soy foam by scanning electron microscope and X-ray computed tomography revealed the internal cell morphology and cell structure.  相似文献   
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This study examines cointegration and Granger causality among global oil prices, precious metal (Gold, Platinum and Silver) prices and Indian Rupee–US Dollar exchange rate using daily data spanning from 2nd January 2009 to 30th December 2011. ARDL bounds tests indicate that the series are cointegrated. Toda–Yamamoto version of Granger causality has been employed to establish the causation amongst the variables. The study also examines generalized error variance decomposition of variables due to various shocks in the system. Such information provides insight into the transmission links between the global oil market and the Indian precious metals and foreign exchange market. These have the potential for significant impact in further research, portfolio management and central bank policy design.  相似文献   
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The uptake in Europe of Energy from Waste (EfW) incinerator plants has increased rapidly in recent years. In the UK, 25 municipal waste incinerators with energy recovery are now in operation; however, their waste supply chains and business practices vary significantly. With over a hundred more plant developments being considered it is important to establish best business practices for ensuring efficient environmental and operational performance. By reviewing the 25 plants we identify four suitable case study plants to compare technologies (moving grate, fluidised bed and rotary kiln), plant economics and operations. Using data collected from annual reports and through interviews and site visits we provide recommendations for improving the supply chain for waste incinerators and highlight the current issues and challenges faced by the industry. We find that plants using moving grate have a high availability of 87–92%. However, compared to the fluidised bed and rotary kiln, quantities of bottom ash and emissions of hydrogen chloride and carbon monoxide are high. The uptake of integrated recycling practices, combined heat and power, and post incineration non-ferrous metal collections needs to be increased among EfW incinerators in the UK. We conclude that one of the major difficulties encountered by waste facilities is the appropriate selection of technology, capacity, site, waste suppliers and heat consumers. This study will be of particular value to EfW plant developers, government authorities and researchers working within the sector of waste management.  相似文献   
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This study was undertaken to assess the pulmonary and respiratory problems of workers in a zarda factory. A total of 70 permanent zarda workers (50 manufacturing workers and 20 office ones) were studied in a factory in Baguihati, Kolkata, India. The study included (a) completion of a questionnaire (on pulmonary and respiratory problems), (b) measurement of physical parameters, (c) spirometry and (d) measurement of peak expiratory flow rate. At the same time, the worksite was analyzed with an OSHA-recommended ergonomics checklist. Many zarda manufacturing workers complained of respiratory symptoms. Continuous exposure to the tobacco processing environment reduced the workers' lung volume and peak expiratory flow rates. Our study indicates that zarda manufacturing workers may have respiratory and pulmonary disorders related to exposure to tobacco dust in their work environment.  相似文献   
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Steel dominates the global metal production accounting for 5 % of increase in Earth’s atmospheric carbon dioxide (CO2). Today, India is the 4th largest producer of crude steel in the world. The sector contributes around 3 % to the country’s gross domestic product (GDP) but adds 6.2 % to the national greenhouse gas (GHG) load. It accounts for 28.4% of the entire industry sector emissions, which are 23.9% of the country’s total emissions. Being a developing country, India is not obliged to cut its emissions under the Kyoto Protocol to the United Nations Framework Convention on Climate Change (FCCC), but gave voluntary commitment to reduce the emission intensity of its GDP by 20–25 % from the 2005 level by 2020. This paper attempts to find out if the Indian steel sector can help the country in fulfilling this commitment. The sector reduced its CO2 emissions per ton of steel produced by 58% from 1994 to 2007. The study generates six scenarios for future projections which show that the sector can reduce its emission intensity by 12.5 % to 63 %. But going by the conservative estimates, the sector can reduce emission intensity by 30 % to 53 %. However, actual emissions will go up significantly in every case.  相似文献   
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