• Nuclear Engineering and Technology
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• 제38권6호
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• pp.459-482
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• 2006

A geochemical approach to the long-term safety of waste disposal is discussed in connection with the significance of actinides, which shall deliver the major radioactivity inventory subsequent to the relatively short-term decay of fission products. Every power reactor generates transuranic (TRU) elements: plutonium and minor actinides (Np, Am, Cm), which consist chiefly of long-lived nuclides emitting alpha radiation. The amount of TRU actinides generated in a fuel life period is found to be relatively small (about 1 wt% or less in spent fuel) but their radioactivity persists many hundred thousands years. Geological confinement of waste containing TRU actinides demands, as a result, fundamental knowledge on the geochemical behavior of actinides in the repository environment for a long period of time. Appraisal of the scientific progress in this subject area is the main objective of the present paper. Following the introductory discussion on natural radioactivities, the nuclear fuel cycle is briefly brought up with reference to actinide generation and waste disposal. As the long-term disposal safety concerns inevitably with actinides, the significance of the aquatic actinide chemistry is summarized in two parts: the fundamental properties relevant to their aquatic behavior and the geochemical reactions in nanoscopic scale. The constrained space of writing allows discussion on some examples only, for which topics of the primary concern are selected, e.g. apparent solubility and colloid generation, colloid-facilitated migration, notable speciation of such processes, etc. Discussion is summed up to end with how to make a geochemical approach available for the long-term disposal safety of nuclear waste or for the performance assessment (PA) as known generally.

• 한국통신학회논문지
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• 제39A권9호
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• pp.548-556
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• 2014

최근 급증하는 데이터 트래픽에 효율적으로 대응하기 위해 매크로 기지국 영역에 매크로 기지국과 같은 주파수를 사용하는 소형 기지국이 공존하는 이종망에 관한 연구가 활발하게 진행 중이다. 이때, 매크로셀로부터 소형셀로의 간섭을 줄이기 위해 시간 영역에서 ABS (Almost Blank Subframe)을 이용한 enhanced Inter-cell Interference Coordination (eICIC) 기법이 제안되어 있다. 그러나 간섭 문제 해결을 위해 데이터를 전송하지 않는 서브프레임들이 발생함으로써 매크로셀 입장에서는 자원 낭비 문제가 발생한다. 본 논문에서는 능동 안테나 시스템 (AAS)과 Genetic Algorithm (GA)을 이용하여 소형 셀 방향으로 안테나 이득을 줄인 매크로 기지국의 3D 섹터 빔을 형성하여 셀간의 간섭신호 세기가 감소 되도록 하고 데이터 전송에 모든 서브프레임을 이용하여 낭비되는 자원이 없도록 한다. LTE -Advanced 시스템 레벨 시뮬레이터를 통해 기존 eICIC 기법과의 성능을 비교 분석하며, 제안된 기법의 성능 향상을 확인한다.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2003년도 추계정기총회 및 국제심포지엄
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• pp.116-121
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• 2003

In this study, the thermal degradation process has been investigated at various reaction temperature$(350{\sim}400^{\circ}C)$ and times$(30{\sim}120\;min)$ in order to recycle waste plastic films as solid state wax. Waste plastic films were easily melted by adding a small amount of waxes. The effects of wax addition and nitrogen flow rate on their thermal degradation properties were investigated. FT-IR, GPC and viscometer were used to analyze properties of the solid wax including the structure, molicular weight distribution and melt viscosity. The average molecular weight of solid wax was decreased with increasing the reaction time, temperature and amount of wax added, Also, the viscosity of solid wax decreased with increasing the stirring speed at a constant reaction temperature and time, and its viscosity got close to zero above $390^{\circ}C$.

• 미생물과산업
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• 제19권4호
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• pp.2-13
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• 1993

Some microorganisms, including actinomycetes, cyanobacteria, and other bacteria, algae, fungi, and yeast, can accumulate and retain relatively high quantities of heavy metals and radionuclides from their external environments (1-4). Both living and dead cells can be used for biosorptive metal/radionuclide removal from solution. Thus microorganisms and products excreted by or derived from microbial cells (2) may provide an alternative or adjunct to conventional techniuqes of metal removal and recovery. Recent approaches have separated the microbial growth and metal removal process to manipulate production of metal-adsorptive capacity of bacteria and metal removal process. If pre-grown cells are immobilized and used for metal removal, mathematical modeling can be applied to predict immobilized cell reactor behavior under specific process conditions. Waste and microbial adsorbent could be separated from the treated flow in one step. Once treated, the metal waste is concentrated in a small volume of sorbed form for easy metal disposal or recovery.

• 수산해양교육연구
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• 제11권1호
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• pp.24-42
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• 1999

I have studied historical transition process of fisheries industries, fisheries Institute in abreast of developing fisheries industries of west coast of Korea since 1910 year with regard to the Gogunsan Is. The results were summarized as follows. In 1910 year, fishery industry has been carried out shifting fishing gear e.g set-net in shallow waters, small stow net, small seine net adapting to the tophorgrapical feature, shape of coast, oceanic condition, however, the fishing gear and fishing method were undeveloped, so that, Japanese fishermen had been exploited fisheries resources penetrating the fishing ground. Most important species were lot of captured croaker, cod, spanish mackeral, sea abream, herring in coastal sea. nowaday, squid, anchovy, shrimp, crab, pompret were much captured. The species were captured in 18 century were not captured. It is rarely than that period. Fishereis aquatic culture had been not farmed till 1960 year, but sea laver, shrimp, crab, had been breeded 1970 year also, the fresh water fish e.g. eel, cat-fish had been breeded activately. The fisheries processing industry were composed of salt. icing, dry, method. the salted fish industry had been prevailed at Gangyng, Kwangchon, Kunsan, Julpo comparatively. The fisheries institute had been established at Kunsan at first, but institute established in other region had been abolished in a short time. This phenomenon was related with development of fisheries resources. The western coast fisheries industries had been wasted of decreasing of fisheries resources, variation of environment. Accordingly, the study of preserving the marine resources. educated man power who engaged in fisheries field have to accomplish. Sea was dying with reason of loss of mud in west coast factory waste, waste of life the increase of accident of sea polluted, each illegal fishing industry physical and chemical reason etc. in this respect, Kusan maritime college, fisheries developing agency, institute have to take important role for developing fishing industry.

• 셀메드
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• 제10권3호
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• pp.19.1-19.6
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• 2020

The kidneys are exposed to toxicants and waste product and can be affected easily by these toxicants and by products of the metabolism. The consumption of adequate water is necessary to remove waste and to keep kidney healthy. Deficiency of liquid in the blood leads to various adverse effects on the kidney. The most common adverse deficiency of liquid in blood is deposition of solid matter in the kidney and subsequently formation of kidney stone. Nephrolithiasis (kidney stone) can be treated by drugs if it is small in size but if it blocks the route due to its big size then surgery is the only way to remove it. The recurrence rate of the problem is very high and it may reappear within 10 years. In Unani literature Hasāh wa Raml al-Kulya (nephrolithiasis) is described in detail. As per Unani literature stagnation of Ghalīz mādda (filthy and viscous matter) in the kidney is the main cause of the formation of kidney stone. Various single and compound formulations drugs are described for the management of kidney stone which are very effective as well as safe. Management is divided into two parts i.e. symptomatic treatment to relieve pain and to methods adopted to remove stone from the kidney. Musakkin-i-Waja'(analgesic) drugs are used for pain while Mufattit-i-Hasāh (lithotriptic) and Mudirr-i-Bawl (Diuretic) drugs are used to remove stone. Majoon Aqrab, Qurs Kaknaj and Dawa-e-Gurda etc. are compound drugs mentioned in literature for removal of kidney stone. Single drugs like Alu Balu, Tukhm Khayar, and Kharkhask etc. are also used for same purpose.

• 한국대기환경학회지
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• 제20권1호
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• pp.59-68
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• 2004

In this study, we investigated the concentrations of volatile organic compounds (VOC) in the ambient air of a small scale municipal waste landfill site. Seasonal sampling was carried out simultaneously at two sites, i.e. one in the center of the landfill area, and the other at a boundary site. Among 38 target VOC, toluene appeared to be the most dominant compound, followed by benzene. and xylenes. The higher levels of BTX imply that paint -containing materials and/or organic solvents are the most significant sources of the VOC in the landfill environment. Seasonal variations for the samples collected at the landfill site indicated that the VOC concentrations tend to be higher in the spring and fall season and lower in the winter season. In addition, night- time concentrations appeared to be generally higher than day-time. Such daily variation might be due to more stabilized atmosphere during the night-time. Similar patterns were also found in samples collected at a boundary site. This study demonstrated that the municipal landfill, although it is small -scaled, could be an important emission source of atmospheric VOC, particularly in the vicinities of the landfill. Thus, an appropriate control strategy is required to prevent any undesirable secondary pollutions from the environmental sanitary facilities such as landfill.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.81-91
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• 2013

A novel design process of a parallel multi-flow type air-cooled condenser of a dual-loop waste heat recovery system with Rankine steam cycles for improving the fuel efficiency of gasoline automobiles has been investigated focusing on reduction of the pressure drop inside the micro-tubes. The low temperature condenser plays a role to dissipate heat from the system by condensing the low temperature loop working fluid sufficiently. However, the refrigerant has low evaporation temperature enough to recover the waste from engine coolant of about $100^{\circ}C$ but has small saturation enthalpy so that excessive mass flow rate of the LT working fluid, e.g., over 150 g/s, causes enormously large pressure drop of the working fluid to maintain the heat dissipation performance of more than 20 kW. This paper has dealt with the scheme to design the low temperature condenser that has reduced pressure drop while ensuring the required thermal performance. The number of pass, the arrangement of the tubes of each pass, and the positions of the inlet and outlet ports on the header are most critical parameters affecting the flow uniformity through all the tubes of the condenser. For the purpose of the performance predictions and the parametric study for the LT condenser, we have developed a 1-dimensional user-friendly performance prediction program that calculates feasibly the phase change of the working fluid in the tubes. An example is presented through the proposed design process and compared with an experiment.

• 신재생에너지
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• 제4권2호
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• pp.21-30
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• 2008

Anaerobic digestion (AD) is the most promising method of treating and recycling of different organic wastes, such as OFMSW, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. degradation in the absence of oxygen, organic material is decomposed by anaerobes forming degestates such as an excellent fertilizer and biogas, a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to producing renewable energy and to reducing $CO_2$ and other GHG emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. A classification of the basic AD technologies for the production of biogas can be made according to the dry matter of biowaste and digestion temperature, which divide the AD process in wet and dry, mesophilic and thermophilic. The biogas produced from AD plant can be utilized as an alternative energy source, for lighting and cooking in case of small-scale, for CHP and vehicle fuel or fuel in industrials in case of large-scale. This paper provides an overview of the status of biogas production and utilization technologies.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.202-205
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• 2008

Anaerobic digestion(AD) is the most promising method of treating and recycling of different organic wastes, such as OFMSW, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. degradation in the absence of oxygen, organic material is decomposed by anaerobes forming degestates such as an excellent fertilizer and biogas, a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to producing renewable energy and to reducing $CO_2$ and other GHG emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. A classification of the basic AD technologies for the production of biogas can be made according to the dry matter of biowaste and digestion temperature, which divide the AD process in wet and dry, mesophilic and thermophilic. The biogas produced from AD plant can be utilized as an alternative energy source, for lighting and cooking in case of small-scale, for CHP and vehicle fuel or fuel in industrials in case of large-scale. This paper provides an overview of the status of biogas production and utilization technologies.