• Journal of Korea Foundry Society
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• v.25 no.5
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• pp.203-208
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• 2005

The main emphasis of this study is to optimize the process variables for manufacturing aluminum foam materials by direct foaming of remelted aluminum scraps. Aluminum foams were fabricated from two different raw materials, pure aluminum and used beverage cans. For both cases, $TiH_{2}$ was used as a foaming agent. Calcium was added as a thickener for the foaming of pure aluminum and no thickener was added for that of used beverage Cans because the pre-existing oxides of the used beverage cans are used as a thickener. Calcium and $TiH_{2}$ content varies from 0.5wt.% to 2.0wt.% and from 0.5wt.% to 1.5wt.%, respectively. The processing conditions, such as the effect of calcium on the melt viscosity, foaming temperature, and the optimum amount of the foaming agent with regard to the melt viscosity were discussed.

• Environmental and Resource Economics Review
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• v.10 no.3
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• pp.413-431
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• 2001

Previous analyses of deposit-refund systems (hereafter DRS) mosty concerned consumer-paid DRS. While there has been a trend to put more emphasis on the producers' responsibility in recycling, especilly in Europe, and the supplier-paid DRS has been enforced in Korea during the past decade, little attempt has been made to analyse rigorously the nature of the supplier-paid DRS. This paper looks into the effects of the supplier-paid DRS on firm behaviors and profits under the oligopolistic market structure. It is shown that, in the cournot model where firms strategically interact each other, when the deposit rate is high enough, firms' profit increase as the deposit rate rises. Furthermore, where the number of firms are sufficiently large, it can happen that, as the deposit rate increases, both social welfare and firms' profit improve.

• Korean Management Science Review
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• v.13 no.2
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• pp.13-24
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• 1996

CIM and JIT have been known as a suitable production system under various product with small quantity production environment which demands short delivery, high quality, and flexibility. CIM is the integrated system for both automated facilities and computer information processing technology and JIT is the system for an exhaustive waste elimination. This paper proposes the JIT-CIM system which combines the concepts and characteristics of JIT and CIM. The JIT-CIM system has been implemented under the strategy of management such as market-in, integration, recycling and resonable profit and which integrates the automation facilities and information processing technology on the basis of waste elimination concept and small lot pronciple of JIT.

• Korean Journal of Construction Engineering and Management
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• v.7 no.3 s.31
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• pp.159-168
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• 2006

In order to respond to interest and regulations in sustainable environment which is increasing, construction industry needs to establish a sustainable production system. When generation of wastes can be diminished and recycling of them raised in the construction site as a part of a sustainable production system, it might contribute to not only establishing a sustainable production system but also gaining economical profit. This study is a preliminary research for establishing a sustainable production system, which aims to identify construction waste generation patterns and factors causing construction waste generation. Case studies were implemented to investigate these patterns and factors.

• Journal of Dairy Science and Biotechnology
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• v.27 no.1
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• pp.13-18
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• 2009

We confirmed methane production and reduction of pollution during anaerobic digestion of milk waste and analyzed the economic potential of using milk waste as a renewable energy source. The milk waste sludge was obtained from the Pasteur milk factory and processed by anaerobic digestion to produce methane. The methane production from two completely mixed tank reactors with an effective capacity of 6 ${\ell}$, 15 days of hydraulic retention time (HRT), and a mid-temperature of $35^{\circ}C$ averaged 4.11 ${\ell}$/day. The total chemical oxygen demand (TCOD) during production decreased from an initial 31,416 mg/${\ell}$ to 13,500 mg/${\ell}$, showing a maximum TCOD removal efficiency of 60%. When HRT was reduced to 12 days, methane production increased by 44% under a high-temperature condition of $55^{\circ}C$. An economic analysis based on these results was applied to a Korean milk factory of typical size and demonstrated that the installation of an anaerobic digester could provide sufficient economic profit.