• Nuclear Engineering and Technology
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• v.43 no.2
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• pp.149-158
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• 2011

Metal waste generated from the pyroprocessing of 10 MtU of spent fuel was classified by comparing the specific activity of a relevant radionuclide with the limit value of the specific activity specified in the Korean acceptance criteria for a lowand intermediate-level waste repository. A Korean Optimized Fuel Assembly design with a 17${\times}$17 array, an initial enrichment of 4.5 weight-percent, discharge burn-up of 55 GWD/MtU, and a 10-year cooling time was considered. Initially, the mass and volume of each structural component of the assembly were calculated in detail, and a source term analysis was subsequently performed using ORIGEN-S for these components. An activation cross-section library generated by the KENO-VI/ORIGEN-S module was utilized for top-end and bottom-end pieces. As a result, an Inconel grid plate, a SUS plenum spring, a SUS guide tube subpart, SUS top-end and bottom-end pieces, and an Inconel top-end leaf spring were determined to be unacceptable for the Gyeongju low- and intermediate-level waste repository, as these waste products exceeded the acceptance criteria. In contrast, a Zircaloy grid plate and guide tube can be placed in the Gyeongju repository. Non-contaminated Zircaloy cladding occupying 76% of the metal waste was found to have a lower level of specific activity than the limit value. However, Zircaloy cladding contaminated by fission products and actinides during the decladding process of pyroprocessing was revealed to have 52 and 2 times higher specific activity levels than the limit values for alpha and $^{90}Sr$, respectively. Finally, it was found that 88.7% of the metal waste from the 17${\times}$17 Korean Optimized Fuel Assembly design should be disposed of in a deep geological repository. Therefore, it can be summarized that separation technology with a higher decontamination factor for transuranics and strontium should be developed for the efficient management of metal waste resulting from pyroprocessing.

• The Korean Journal of Zoology
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• v.7 no.1
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• pp.33-38
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• 1964

한국산 도롱뇽 (Hynobius leechi BOULENGER) 발생배의 질소화합물의 대사를 연구하고져 발생단계에 따른 단백질구성(아미노) 산의 촉진(아미노) 산의 정성적 분석과 질소 배설물(ammonia, urea, uric acid, creatine and/or creatinine, total nitrogen)의 정량분석을 미수정란, 란할배, 포배, 양배, 신경배 및 부화직전의 배에 대하여 행하였다. 1. 발생단계에 따른 발생배내 단백질구성 (아미노산)은 전 단계를 통하여 일양하게 18종씩 검출되어TRh 유리 (아미노산) 은 17 내지 23 종 검출되었으며, 전체적으로 유리(아미노산) 분포상에 큰 변화가 없었다. 2. 발생단계에 따른 질소배설물 분석의 결과는 다음과같다. Ammonia 와 urea 의 배내 함량은 미수정란에서부터 양배까지 점차 감소하여 양배 이후 부화직전배까지 급격히 증가한다. Uric acid의 함량은 전 단계를 통해 미소하였으며 creating and/or creatininie 은 본 실험에서는 검출되지 않았다. 3. 발생단계에 따른 발생배내 ammonia 함량에 대한 sodium azide의 영향은 농도에 따라 이원적인 특이성을 가지고 있었다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.75-78
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• 1996

End Milling is avilable for machining the variable shape of products and has been widely applicated in many industries. To manufacture precise products a surface roughness has to be noticable as a improtant parameter. In end milling the research for tool wear has been insufficient because the tool shape and the cutting geometry are complicated. In this paper the pattern of endmill wear is investigated and the machinability is evaluated. As finding out the characteristics of cutting force and surface roughness the effect of endmill wear on machinability is investigated.

• IE interfaces
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• v.20 no.2
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• pp.154-161
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• 2007

When the electrical appliances such as TVs and refrigerators become obsolete, they must be collected to the recycling centers to avoid environmental damages. The obsolete home appliances are first moved to the regional collection point; and then transported to one of the recycling centers. Each recycling center has a limited capacity; and some recycling centers can process only certain types of products. For given locations of the existing collection points and recycling centers, optimally assigning the obsolete home appliances of each type from each collection point to the recycling centers can significantly reduce the total transportation cost. We formulate this problem as an LP problem. We also present an approach to determine the locations of additional recycling centers in order to alleviate the over-utilization of the current recycling centers.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.833-838
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• 2012

The thermal degradation products of polytrimethylene terephthalate (PTT) obtained by heating the sample in the temperature range of $250-360^{\circ}C$ under non-oxidative conditions was characterized using MALDI-TOF (matrix assisted laser desorption/ionization) mass spectrometry. The structures of the degradation products were determined and the relative compositions were estimated. The MALDI-TOF mass spectra of the thermally degraded PTT sample showed three main series of oligomer products with different end groups, which were carboxyl/carboxyl, carboxyl/allyl, and allyl/allyl. In contrast to the thermal degradation of polyethylene terephthalate (PET), the oligomers containing terephthalic anhydrides were not detected, whereas the formation of oligomers containing the unsaturated allyl ester group was confirmed by mass assignment. From these results, it was concluded that the thermal degradation of PTT proceeds exclusively through the ${\beta}$-CH hydrogen transfer mechanism, which is in accordance with the proposed reaction mechanism for the thermal degradation of polybutylene terephthalate (PBT).

• Safe Food
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• v.8 no.2
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• pp.24-30
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• 2013

• 한국약용작물학회:학술대회논문집
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• 2011.09a
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• pp.272-273
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• 2011

• Journal of the Korea Safety Management & Science
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• v.6 no.2
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• pp.187-197
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• 2004

The recycling cell formation problem means that disposal products are classified into recycling product families using group technology in their end-of-life phase. Disposal products have the uncertainties of product condition usage influences. Recycling cells are formed considering design, process and usage attributes. In this paper, a new approach for the design of cellular recycling system is proposed, which deals with the recycling cell formation and assignment of identical products concurrently. Fuzzy ART neural networks are applied to describe the condition of disposal product with the membership functions and to make recycling cell formation. The approach leads to cluster materials, components, and subassemblies for reuse or recycling and can evaluate the value at each cell of disposal products. Disposal refrigerators are shown as an example.

• Proceedings of the Safety Management and Science Conference
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• 2000.05a
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• pp.111-123
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• 2000

The recycling cell formation problem means that disposal products are classified into recycling part families using group technology in their end of life phase. Disposal products have the uncertainties of product status by usage influences. Recycling cells are formed considering design, process and usage attributes. In this paper, a novel approach to the design of cellular recycling system is proposed, which deals with the recycling cell formation and assignment of identical products concurrently. Fuzzy clustering algorithm and Fuzzy-ART neural network are applied to describe the states of disposal product with the membership functions and to make recycling cell formation. This approach leads to recycling and reuse of the materials, components, and subassemblies and can evaluate the value at each cell of disposal products. Application examples are illustrated by disposal refrigerators, compared fuzzy clustering with Fuzzy-ART neural network performance in cell formation.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.294-299
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• 2009

Micro end-milling has been becoming an important machining process to manufacture a number of small products such as micro-devices, bio-chips, micro-patterns and so on. Many related researches have given grand effects to micro end-milling phenomenon, for example, micro end-milling mechanism, cutting force modeling and machinability. This paper strongly concerned actual problem, micro tool deflection, which causes excessive machining errors on the workpiece. Machining error were predicted and measured through a series of test micro cutting and analysis of their SEM images and FEM analysis. Experiments are carried out to validate the approaches.