• Journal of Veterinary Clinics
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• v.26 no.1
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• pp.23-28
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• 2009

Peritoneal dialysis (PD) is a clinical technique that therapeutically removes toxic solutes from body fluids and normalizes endogenous solutes whose aberrant concentrations disrupt normal physiology. This study retrospectively evaluated clinical outcomes and complications of PD in 20 dogs with renal failure. Blood works (total count of red blood cells (RBC), packed cell volume (PCV), the serum biochemical, and electrolyte values related to renal insufficiency) and complications associated with peritoneal dialysis, and clinical outcomes were recorded before and after PD. Additionally, creatinine reduction ratio (CRR) and urea nitrogen reduction ratio (URR) were calculated for evaluating the efficacy of PD. PD resulted in a significant (p < 0.05) reduction in blood urea nitrogen (BUN) concentration in 19 dogs, while a significant (p < 0.05) reduction in creatinine concentration in 17 dogs. The complications of PD were hypoalbuminemia (12/20, 60%), anemia (10/20, 50%), subcutaneous dialysate leakage (9/20, 45%), bacterial peritonitis (6/20, 30%), dialysate retention (5/20, 25%) and limb edema (4/20, 20%). This study demonstrated that PD was effective in reducing the magnitude of azotemia in dogs with renal failure especially in acute phase, although the complication rate was high but manageable.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.1-7
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• 2019

Most oil refineries and chemical plants have flare systems designed to mitigate pressure rises in process facilities in case of emergencies that require the release of large amounts of gas due to sudden process shutdowns such as power outages. However, the rise of the flame of the flare system causes civil complaints from residents around the factory due to visible pollution, and economic loss occurs in the company, which requires constant management. In this study, two items were diagnosed and analyzed in order to derive the optimal operation method of flare system. First, to detect the cause of the rise in flame height, the acoustic leak detector was used to check gas leaks in safety valves and pressure control valves. Second, to identify the cause of flame instability, the pulsation phenomenon was diagnosed through the CFD simulation and modeling experiments of the sealing drum. By confirming the leak at 4.3% of the safety valve and 10% of the pressure control valve, the cause of abnormal sparking was derived. The information presented in this study can be easily applied to any company that has a flare system, and is expected to prevent complaints and product loss.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.3
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• pp.98-109
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• 2002

Each kinds of the leather process wastes which is occurred in the leather making process is almost more than 50% on the basis of the raw hide. The emitted process wastes are important oil and fats and protein resources because they are composed of animal oil and fats and fibrous protein. But most of them are incinerate or filled up simply as the industrial wastes without applying to recycling into the other use. Thus the problems of environmental pollution are becoming more critical and the processing cost of the leather process wastes (40,000~60,000 won) is a heavy burden on the production cost. Because the organic wastes such as fleshing scrap, pelt scrap are high fetid, its unlawful abandonment without being processed properly causes the occurrence of secondary pollution by an offensive odor and leakage of waste water. Thus we made the re-resource experiments in order to resolve this problems. The principal contents of this study are to process the collected leather waste scrape through separate the oil and fat ingredients with various propert by processing various chemicals and enzymes on the next effector. The re-resource application of separated oil and fat ingredients produced chemical for leather applicable to manufacturing process of leather through chemical transformation process(sulphation reaction, sulphitation reaction etc.) of oil and fats.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.115-115
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• 2010

고휘도 고효율 백색 LED (lighting emitting diode)가 차세대 조명광원으로 급부상하고 있다. 백색 LED를 생산하기 위한 공정에서 MOCVD (유기금속화학증착)장비를 이용한 에피웨이퍼공정은 에피층과 기판의 격자상수 차이와 열팽창계수차이로 인하여 생성되는 에피결함의 문제로 기판과 GaN 박막층 사이에 완충작용을 해줄 수 있는 버퍼층 (Buffer layer)을 만든다. 그 위에 InGaN/GaN MQW (Multi Quantum Well)공정을 하여 고휘도 고효율 백색 LED를 구현 할 수 있다. 이 공정에서 기판의 온도가 불균일해지면 wafer 파장 균일도가 나빠지므로 백색 LED의 yield가 떨어진다. 균일한 기판 온도를 갖기 위한 조건으로 기판과 induction heater의 간격, 가스의 흐름, 기판의 회전, 유도가열코일의 디자인 등이 장비의 설계 요소이다. 본 연구에서는 유도가열방식의 유도가열히터를 이용하여 기판과 히터의 간격에 차이에 따른 기판 균일도 측정했고, 회전에 의한 기판의 온도분포와 자기장분포의 실험적 결과를 상용화 유체역학 코드인 CFD-ACE+의 모델링 결과와 비교 했다. 또한 가스의 inlet위치에 따른 기판의 온도 균일도를 측정하였다. 본 연구에서 사용된 가열원은 유도가열히터 (Viewtong, VT-180C2)를 사용했고, 가열된 흑연판 표면의 온도를 2차원적으로 평가하기 위하여 적외선 열화상 카메라 (Fluke, Ti-10)를 이용하여 온도를 측정했다. 와전류에 의한 흑연판의 가열 현상을 누출 전계의 분포로 확인하기 위하여 Tektronix사의 A6302 probe와 TM502A amplifier를 사용했다. 흑연판 위에 1 cm2 간격으로 211곳에서 유도 전류를 측정했다. 유도전류는 벡터양이므로 $E{\theta}$를 측정했으며, 이때의 측정 방향은 흑연판의 원주방향이다. 또한 자기장에 의한 유도전류의 분포를 확인하기 위하여 KANETEC사의 TM-501을 이용하여 흑연판 중심으로부터 10 mm 간격으로 자기장을 측정 했다. 저항 가열 히터를 통하여 대류에 의한 온도 균일도를 평가한 결과 gap이 3 mm일때, 평균 온도 $166.5^{\circ}C$에서 불균일도 6.5%를 얻었으며, 회전에 의한 온도 균일도 측정 결과는 2.5 RPM일 때 평균온도 $163^{\circ}C$에서 5.5%의 불균일도를 확인했다. 또한 CFD-ACE+를 이용한 모델링 결과 자기장의 분포는 중심이 높은 분포를 나타냄을 확인했고, 기판의 온도분포는 중심으로부터 55 mm되는 곳에서 300 W/m3로 가장 높은 분포를 나타냈다. 가스 inlet 위치를 흑연판 중심으로 수직, 수평 방향으로 흘려주었을 때의 불균일도는 각각 10.5%, 8.0%로 수평 방향으로 가스를 흘려주었을 때 2.5% 온도 균일도 향상을 확인했다.

• Economic and Environmental Geology
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• v.42 no.4
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• pp.335-342
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• 2009

The effects of bacterial lysis on the rate of quartz dissolution were investigated under pH 7 condition using Bacillus subtilis cells which were either irradiated or non-irradiated with gamma ray. The amount of dissolved organic carbon (DOC) which resulted from bacterial lysis increased in slurries of quartz and bacteria mixture over experimental period. Lysis of non-irradiated bacteria led to the elevated concentration of dissolved silicon when compared with abiotic control. Concomitant increase in the amounts of DOC and dissolved silicon over time indicated that lixiviation of silicon from quartz was due to bacterial lysis. Higher amounts of DOC and dissolved silicon were present in the irradiated bacterial slurries than those of non-irradiated bacteria. The enhancement of quartz dissolution in the irradiated bacterial slurries was likely attributed to disruption of organic molecules in the bacterial cells by gamma ray and formation of effective ligands for quartz dissolution. The results suggest that the effects of bacterial lysis on mineral weathering rate should be considered for prediction of time for released radionuclides to migrate to surface biosphere in high level radioactive waste disposal site.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.382-387
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• 2008

$Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ oxide was synthesized by polymerized complex method. Dense membrane of perovskite oxide was prepared using as-prepared powder by pressing and sintering at $1080^{\circ}C$. Leakage test was conducted on the membrane sealed by gold ring, Pyrex ring or Pyrex powder as a sealing material. The oxygen permeation flux of $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membrane increased with increasing temperature and was $0.74mL/min{\cdot}cm^2$ at $900^{\circ}C$. In the case of the membrane applied by sealing material, oxygen permeation flux of the membrane using gold ring at $950^{\circ}C$ was higher than that using Pyrex materials because the undesired spreading of Pyrex glass materials in the membrane led to the reduction of effective permeation area. Microphotograph analysis results for the membrane after permeation test confirmedthe diffusion of Pyrex glass seal into the membrane.

• Journal of Radiation Protection and Research
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• v.30 no.3
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• pp.99-105
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• 2005

A model for evaluating radioactive contamination in the urban environment, named METRO-K, was developed as a basic step for accident consequence analysis in case of an accidental release. The three kind of radionuclides $(^{137}Cs,\;^{106}Ru,\;^{131}I)$ and the different chemical forms of iodine (particulate, organic and elemental forms) are considered in the model. The radioactive concentrations are evaluated for the five types of surface (roof, paved road, wall, lawn/soil, tree) as a function of time. Using the model, the contaminative impacts of the surfaces were intensively investigated with respect to with and without precipitation during the measurement periods of radionuclides in air. In addition, a practical application study was conducted using $^{137}Cs$ concentration in air and precipitation measured in an European country at the Chernobyl accident. As a result precipitation was an influential factor in surface contamination. The degree of contamination was strongly dependent on the types of radionuclide and surface. Precipitation was more influential in contamination of $^{137}Cs$ than that of $^{131}I$ (elemental form).

• Journal of the Korean Institute of Gas
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• v.21 no.2
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• pp.32-40
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• 2017

Safety Instrumented Systems (SIS) have wide application area. They are of vital importance at process plants to detect the onset of hazardous events, for instance, a release of some hazardous material, and for mitigating their consequences to humans, material assets, and the environment. The integrated safety systems, where electrical, electronic, and/or programmable electronic (E/E/PE) devices interact with mechanical, pneumatic, and hydraulic systems are governed by international safety standards like IEC 61508. IEC 61508 organises its requirements according to a Safety Life Cycle (SLC). Fulfilling these requirements following the SLC can be complex without the aid of SIS supporting tools. This paper presents simple SIS support tool which can greatly help the user to implement the design phase of the safety lifecycle. This tool is modelled in the form of Android application which can be integrated with a Web-based data reading and modifying system. This tool can reduce the computation time spent on the design phase of the SLC and reduce the possible errors which can arise in the process. In addition, this paper presents an optimization approach to SISs based on cost measures. The multi-objective genetic algorithm has been used for the optimization to search for the best combinations of solutions without enumeration of all the solution space.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.710-714
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• 2011

In present work, $La_{0.8}Ca_{0.2}CrO_{3}$(LCC), $La_{0.8}Sr_{0.2}CrO_{3}$(LSC) and $La_{0.8}Ca_{0.2}CrO_{0.9}Co_{0.1}O_{3}$(LCCC) ceramic interconnect layer for SOFC were prepared by using thermal plasma spray coating process. The LCC, LSC and LCCC powders were characterized by x-ray diffraction(XRD), scanning electron microscopy(SEM), particle counter and BET analysis. In addition, basic and essential properties such as the surface morphology, cross section, gas leak rate, and electrical conductivity of LCC, LSC, and LCCC layers coated by thermal plasma spray coating process were analyzed and discussed. Based on these experimental results, it can be concluded that the LCCC layer coated by thermal plasma spray coating process can be suitable as a ceramic interconnect of SOFC.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.185-192
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• 2010

The chemical-looping combustion(CLC) has advantages of no energy loss for separation of $CO_2$ without $NO_x$ formation. This CLC system consists of oxidation and reduction reactors where metal oxides particles are circulating through these two reactors. In the present study, the reaction kinetic equations of iron oxide oxygen carriers supported on bentonite have been determined by the shrinking core model. Based on the reactivity data, design values of solid circulation rate and solids inventory were determined for the rector. Two types of interconnected fluidized bed systems were designed for CLC application, one system consists of a riser and a bubbling fluidized bed, and the other one has a riser and two bubbling fluidized beds. Solid circulation rates were varied to about $30kg/m^2s$ by aeration into a loop-seal. Solid circulation rate increases with increasing aeration velocity and it increases further with an auxiliary gas flow into the loop-seal. As solid circulation rate is increased, solid hold up in the riser increases. A typical gas leakage from the riser to the fluidized bed is found to be less than 1%.