• Journal of Korean Society of Industrial and Systems Engineering
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• v.47 no.2
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• pp.40-47
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• 2024

As environmental concerns escalate, the increase in recycling of aluminum scrap is notable within the aluminum alloy production sector. Precise control of essential components such as Al, Cu, and Si is crucial in aluminum alloy production. However, recycled metal products comprise various metal components, leading to inherent uncertainty in component concentrations. Thus, meticulous determination of input quantities of recycled metal products is necessary to adjust the composition ratio of components. This study proposes a stable input determination heuristic algorithm considering the uncertainty arising from utilizing recycled metal products. The objective is to minimize total costs while satisfying the desired component ratio in aluminum manufacturing processes. The proposed algorithm is designed to handle increased complexity due to introduced uncertainty. Validation of the proposed heuristic algorithm's effectiveness is conducted by comparing its performance with an algorithm mimicking the input determination method used in the field. The proposed heuristic algorithm demonstrates superior results compared to the field-mimicking algorithm and is anticipated to serve as a useful tool for decision-making in realistic scenarios.

• Geotechnical Engineering
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• v.12 no.3
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• pp.17-34
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• 1996

The objective of this paper is to evaluate the asphalt mixture performance with pyrolyzed carbon black(CBP) and air -cooled iron blast furnace slag. Marshall mix design was performed to determine the optimum binder content, The optimum binder content ranged from 6.3 percent to 7.75 percent. Dynamic creep testing was carried out using mixtures at the optimum binder content. Based on the test results, the use of pyrolyzed carbon black and slag in the asphalt pavement showed a positive result, such as the increase of Marshall stability, the decrease of the strain rate and the decrease in the mix stiffness rate at high temperature(5$0^{\circ}C$) and 137.9 kPa confinement. Within the limits of this research. it was concluded that pyrolyzed carbon black as an additive and slag as a coarse aggregate could be used to produce an asphalt paving mixture that has good stability, stiffness, and rutting resistance.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.5
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• pp.518-526
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• 2012

The objective of this research was to develop fugitive emission models of HFC-134a (Hydrofluorocarbon-134a) at the operation and disposal stages of passenger cars. It is essential to estimate the emission of HFC-134a from mobile air conditioner (MAC) due to its high Global Warming Potential (GWP) and extensive use as a refrigerant in MAC. The first-order emission model was introduced and the emission rate constant was assumed to be unvaried with time. A commercial recovery station of refrigerants was used to recover the HFC-134a from the MAC. Average emission rate constant and annual emission rate during the operation period of vehicle are estimated to be $0.0538{\pm}0.0092$ (n=21) $yr^{-1}$ and $5.2{\pm}0.6%$, respectively within a confidence interval of 95%. According to the model results, about 50% of HFC-134a would be emitted from the MAC during the 10 years operation of passenger cars. On the other hand, average remaining portion of HFC-134a in the MACs of scrap cars is $58.2{\pm}4.8%$ (n=50) within a confidence interval of 95%, suggesting that over 40% of the initially charged amount could be released fugitively after disposal provided that the HFC-134a would not be properly treated or recycled.

• The Journal of Fisheries Business Administration
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• v.37 no.2 s.71
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• pp.111-139
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• 2006

Cold storage warehouse industry in Japan has been extended in its scale in terms of both the number of storages and cold storage capacity in order to meet the extended reproduction of the marine products industry. However, increasing total amount of the stored goods since mid 80s led to relative decrease of marine products while the number of storages was remained the same or decreased, though cold storage capacity was gradually increased and is maintained the increase of the average cold storage capacity. As structural change in the cold storage warehouse industry emerges, cold storage warehouses require new approach to individual storage management with 1)diversity of the stored goods; 2) more competition due to increase of the cold storage capacity; and 3) sizing of the average cold storage capacity. Therefore, this study analyzed how cold storage warehouse management activity with individual storage sizing changes; and significance of sizing and functional change in cold storage warehouses experiencing sizing, by observing leading cold storage warehouse industry of the metropolitan area in Japan. In conclusion, reorganization of cold storage warehouse industry in the metropolitan area in Japan can be summarized as follows: First, competition among cold storage warehouses in the metropolitan area in Japan is not simply limited to storage industry but extended to establishment and securing physical distribution function. Second, since cold storage warehouse industry is in Scrap & Build phase, decision of management executives on whether taking direction to maintain/continue enhancement of physical distribution function may cause drastic reorganization in the cold storage warehouse industry, Third, since profit of physical distribution management based on cold storage warehouses is insignificant, it is not easy to accomplish expected management outcome, Fourth, today's cold storage warehouse industry mainly characterized by diversity of the stored goods needs facility reorganization with comprehensive and functional integration covering from F class cold storage capacity to F&C class.

• Clean Technology
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• v.19 no.2
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• pp.75-83
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• 2013

In the present paper, we review recycling and applications of titanium binary alloy scraps. The recycling techniques are to successfully prepare low oxygen content ingots using hydrogen plasma arc melting (HPAM) and to produce low oxygen content titanium alloy powders by Hydrogenation-dehydrogenation (HDH) and Deoxidation in solid state (DOSS) process. In addition, as applications of the titanium binary alloy scraps, Ti based solid-solution carbide powders, which would be used for producing Ti based solid-solution cermets with high toughness, were prepared using the titanium binary alloy scraps. These results confirmed that the titanium alloy scraps could be recycled and refined using the HPAM. The resulting oxygen content of the titanium alloy powders were below 1,000 ppm after powderizing. Finally, we had confirmed that the refined titanium alloy powders were able to be utilized as raw materials for preparing the toughened cermets.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.17.1-17.1
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• 2009

발포금속은 1948년에 Sosnik에 의해 알루미늄에 수은을 증발시키는 방법으로 발포 알루미늄을 제조한 이래, 1951년 Elliot에 의해 진보된 방식인 발포 매개체를 용탕에혼입하는 방법으로 발포금속을 제조하기 시작하였다. 현재 이들 선진국가의 생산방법 및 현황은 균질 기공의 조절, 연속주조 방식과 원가절감, 그리고 제조기술의 진보를 통하여 다양한 분야에 적용되고 있다. 그러나 실용화를 위해서는 요구특성을 만족하고 동시에 가격 경쟁력을 가진 제조기술의 보유 및 개발과 독특한 특성을활용한 새로운 적용 분야의 개척이 필요하다고 생각되며, 이를 위해 Harvard, MIT, Aachen, HMI 등 구미 유수 대학과 NASA, 미국방성등의 연구기관, ERG, 신강(新鋼) wire등 산업체를 중심으로제조 및 특성평가에 관한 기초연구와 활용방안이 활발히 모색중에 있다. 그리고 일부 자동차 생산 업체를중심으로 발포금속을 적용한 초경량, 에너지 절감형의 자동차 부품 소재,항공기 방열판 등에 대한 연구가 활발하게 진행되고 있다. 특히 금속 기체의 GASAR 공법은 Lotus 공법으로 Osaka 대학에서 개발되어 열교환기, 항공기, 방열기 등으로 응용이 확대되고 있다 국내에서 완제품생산은 실내장식용 복합패널로서 한소 프라임이 운영상의 문제로 생산을 중단하였으며, 유닉슨(주), 금강(주)에서 Batch식, 금성산업에서 Pot식이 일부 생산 및 연구가 진행되었으나 현재는 본연구실의 협조로 (주) 폼텍에서 발포패널을 주로 생산하고 있고 (주)드림메탈과 (주)아크로폼텍에서일부 생산되고, (주)동일알루미늄에서는 폐 scrap을 이용한 발포 Al 제조가 연구단계에 있다. 생기원에서는 분말 가열 흡음패널이 개발되었으나 강도와 내열성이 낮아 이들 특성을 향상시크는 연구가 진행중이다. 이들 제품은 성능상으로는 동양강판의 흡음패널과 KIMM의 필터용은연구개발이 낮은 수준이며, 본 연구팀과 공동 개발한 (주)폼텍의 복합패널은 10여 가지의 실용특허로 건축마감재로서 오히려 선진국수준을능가한 상태이다, 한편, 발포금속 기능성 개발은, 이들이 가지고 있는 우수한 특성 때문에 군수용으로부터 민수 산업용까지 전분야에 적용이 가능한 소재이므로 수요처를확장하고 있으므로 제품의 균질성, 안정성과 기능성 개발 향상을 위해 지속적이고 체계적인 연구가 필요하다고 생각된다.

• Resources Recycling
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• v.16 no.2 s.76
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• pp.63-76
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• 2007

Typical examples as unrecycled materials in Korea were Zinc from the electric arc furnace dust (EAF Dust), and Moiybdenium and Vanadium from the desulfurizing spent catalyst of petrochemical industries. In the otherwise, though recovery of valuable metals from the waste electronic scrap such as printed circuit boards (PCBs) and platinum group metals (PGM) from the waste automobile catalyst have been interesting issues, it is difficult to collect the exact informations or statistics on their material flow system. In this article, The current domestic research trends for unrecycled or less recycled materials have been reviewed, and material flow and recycling technologies on the desulfurizing spent catalyst were surveyed.

• Journal of Environmental Health Sciences
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• v.46 no.1
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• pp.88-95
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• 2020

Object: The purpose of this study was to select priority points for soil management using the location of groundwater and to suggest this method for soil contamination surveys. Method: Groundwater impact range was set to an area of 100 to 500 meters from the center point of agricultural groundwater wells. Data on industrial complex and factory areas, areas of stored or used ores and scrap metals, areas associated with waste and recycling, and traffic-related facilities areas were collected and checked for whether they fall within the groundwater impact range. Longitude and latitude coordinates of these data were mapped on the groundwater impact range using QGIS (Quantum Geographic Information System). Results: Considering the groundwater impact range, the points were selected as follows: 589 points were selected from 6,811 factories and 259 points were selected from 1,511 recycling business points. Traffic-related facility areas were divided between gas stations, bus depots, and auto mechanics. Thirty-four points were selected from 149 bus depots and 573 points were selected from 6,013 auto mechanic points. From the 2,409 gas station points, 323 were selected. Conclusion: Contaminated soil influences groundwater and crops, which can harm human health. However, soil pollution is not easily identified, so it is difficult to determine what has occurred. Pollution must be prevented beforehand and contaminated soil found. By selecting and investigating soil contamination survey points in consideration of the location of groundwater wells, we can safely manage water resources by preventing groundwater contamination in advance.

• Resources Recycling
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• v.13 no.3
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• pp.50-57
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• 2004

Waste aluminum dross is a major waste in the aluminum scrap smelters and its components are mostly alumina and remained metallic aluminum. In the process to extract the remained aluminum from the waste dross by leaching with sodium hydroxide solution, residue is generated and its main component is alumina. This residue could be recycled into ceramic materials such as alumina castable refractories by going through a series of treatments such as washing, drying and roasting. In this study, a pilot plant was constructed and tested to demonstrate the developed technology. One thousand tons of waste aluminum dross could be processed, and about seven hundred tons of ceramic materials produced in the demonstration line. From the test run of the pilot plant, although it was confirmed that the developed technology could be applied to commercialization, several technical improvements were found to be necessary for reducing impurities such as Na, Fe and for reforming drying equipment.

• Resources Recycling
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• v.24 no.1
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• pp.43-50
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• 2015

An extensive literature survey and personal communication with relevant experts made it possible to understand economic and technical feasibility of disposable diaper recycling. Commercial level of soiled diaper recycling technology is currently available from a Dutch company, Knowaste Co., who owns a proprietary separation technology of the pulps, plastics and super absorbing polymer (SAP). In Korea, on the other hand, pre-consumer diaper recycling technology without material separation at its infancy converts manufacturing scraps into refuse plastic fuel (RPF), container/truck cargo boards or automobile boards/sheets. Although previous studies on feasibility of post-consumer recycling in Korea showed mutually contradictory implication, it was found out in this research that significantly positive economic feasibility can be obtained with pre-consumer diaper recycling. Subsequent recycling R&D including pre-consumer scrap and policy support may expedite 'Establishment of Sustainable Society.