• Title/Summary/Keyword: Kim Dong-hwan

Search Result 6,907, Processing Time 0.046 seconds

Depressive Disorders among Hansen Disease Patients Living in a Collective Farm (한 집단 농원 한센병 환자들의 우울장애)

  • Kim, Yun-Gu;Park, Min-Ho;Park, Jae-Won;Song, Joon-Ho;Sim, Seong-Gyun;Lee, Joo-Hyoung;Lee, Hee-Young;Yun, Dong-Il;Jung, Sung-Hwan;Min, Young-Sun;Bae, Geun-Ryang;Jung, Cheoll;Lim, Hyun-Sul;Cheong, Hae-Kwan
    • Journal of agricultural medicine and community health
    • /
    • v.29 no.1
    • /
    • pp.133-145
    • /
    • 2004
  • Objectives: Depression is a major health concern that can be life threatening if not recognized and treated early. However, there is few report on the depressive disorder of Hansen disease patients in Korea. Therefore, the authors executed this study in order to check factors related to a depressive disorder of a Hansen disease patients and compare with factors to reach to a depressive symptoms of ordinary people with studying their life state and the trouble that Hansen disease patients were currently experiencing Method: The authors surveyed depressive symptoms using self-reported questionnaires in 74 Hansen disease patients and 84 controls. The severity of depressive symptoms was measured using Korean Form of Geriatric Depression Scale (KGDS) score. Result: Positive rate of depressive disorders among Hansen disease patients was 70.3% and that the referents was 31.0%. There is significant difference positive rate of depressive disorders between Hansen disease group and the referents in the factors such as gender, age, frequency of going out, familial type, and familial income. Depressive disorder of Hansen disease group was associated with sex, familial income. According to the multiple logistic regression, the odds ratios of the Hansen disease group versus referents, gender, familial income, frequency of going out were significant (p<0.05). Conclusion: Hansen disease patients had statistically significant higher depressive symptom score than the referents. Also, Hansen disease patients who have lower familial income were more likely to have depressive disorders. Therefore, Economical supports and policy are required for the Hansen disease patients.

  • PDF

A Study on the Effect of the Changes of Play Facilities on Rules Changes - Focusing on the City of Seoul - (관련법규 변천이 아파트단지 내 어린이놀이터 변화에 미치는 영향 연구 - 서울시 소재 현장을 중심으로 -)

  • Kim, Dong-Chan;Suh, Joo-Hwan;Park, You-Jeong
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.37 no.2
    • /
    • pp.26-35
    • /
    • 2009
  • This study is an analysis of the design changes of children's play facilities and the related rules and regulations which causes these changes. Accordingly, it is noticed that a site's change of design by legislation and by yearly alternation influences playground design. First, after revising the provisions for the distance from roads and parking lots, the constructing of safety fences between play facilities and the using of durable materials, alterations of the designs have been made a reality. Second, the design changes after the period of regulation transitions were caused by provisions related to the shelter of evergreens and conditions of the sun. Third, the changes of the playgrounds were related to the substitution of exercise facilities for the local residents and in carrying out a hygiene exam more than twice a year. Because a lack of regulatory standards for the design of playgrounds resulted in compliance based on individual interpretation and because a substitution of exercise facilities is part of the way to alleviate these regulations, the conditions of the site under investigation could be projeced. By such changes of regulations and analysis of alterations of playground design, programs for improvement were suggested. It turned out that the composition of the concrete standard in conformity with regulations required closer observance. Moreover, design standards for children's playgrounds are needed, such as the provision of variation in external appearance, the creation of more flexible layouts and the outlining of spaces by themes.

Effect of Dietary Supplementation of Yellow Loess on Performance, Blood Component Profile and Concentration in Feces in Broiler Chickens (사료 내 황토 첨가 급여가 육계의 생산성, 혈액성상 및 계분 내 암모니아 발생량에 미치는 영향)

  • Park, Sung-Bok;Kang, Hwan-Ku;Bang, Han-Tae;Kim, Min-Ji;Choi, Hee-Chul;Chae, Hyun-Seok;Yu, Dong-Jo;Suh, Ok-Suk;Na, Jae-Cheon
    • Korean Journal of Poultry Science
    • /
    • v.37 no.1
    • /
    • pp.9-13
    • /
    • 2010
  • This experiment was conducted to investigate the effect of dietary supplementation of yellow loess on performance and blood component profile in broiler chickens. A total of three hundred sixty, 1 day old broiler chicks (Ross) were randomly divided into 3 groups with 4 replicates of 30 birds each. The experiment feeds were; control (basal diet), 0~10 days (basal diet with yellow loess T1 4%, T2 2%), 11~21 days (basal diet with yellow loess T1 2%, T2 1%), 22~35 days (basal diet with yellow loess T1 1%, T2 1%). The body weight and weight gain of the broilers fed T2 diet was significant higher than the T1 and control treatment (P<0.05). Feed intake was significantly higher than the control during overall period (P<0.05). Total cholesterol in all yellow loess supplemented treatments were significantly higher than the control treatment (P<0.05), and the triglyceride of broiler fed the diet containing T1 was significantly higher than the control and T2 treatment (P<0.05). No significant differences were observed on the total white blood cell (WBC), neutrophil (NE), monocyte (MO) and eosinophil (EO) in all yellow loess supplemented treatments compared to the control. Lymphocyte of T2 treatment was significantly higher than T1 and control treatment (P<0.05). No significant difference was observed on fecal ammonia gas emission, but broiler fed yellow loess was lower than the control treatment. Aa a result, dietary supplementation of yellow loess was improve to weight gain and feed intake of broiler.

The Characteristics of Membranoproliferative Glomerulonephritis I Detected from School Urine Screening (학교 집단 소변 검사로 발견 된 막증식성 사구체신염 I형의 특성)

  • Choi, Jung-Youn;Park, Mi-Young;Lee, Yong-Jik;Ha, Il-Soo;Cheong, Hae-Il;Choi, Yong;Park, Young-Seo;Han, Hye-Won;Jin, Dong-Kyu;Chung, Woo-Yeong;Kim, Kee-Hyuck;Yoo, Kee-Hwan;Park, Yong-Hoon
    • Childhood Kidney Diseases
    • /
    • v.10 no.2
    • /
    • pp.152-161
    • /
    • 2006
  • Purpose : In Korea, the school urine screening program is a useful tool for screening urine abnormalities. It is particularly useful in early detection of membranoproliferative glomerulonephritis(MPGN) I, which frequently progresses to chronic renal failure. In this study, we studied the medical history, laboratory findings, and histologic findings of MPGN to gain helpful information on early detection and treatment. Methods : The subjects were 19 children, who were diagnosed with MPGN from kidney biopsies that were performed in ten nationwide university hospitals because of abnormal urine findings from school urine screening programs conducted from July 1999 to April 2004. We divided the patients into 2 groups, a nephrotic range proteinuria group(n=8) and a non-nephrotic proteinuria group(n=11), and retrospectively analyzed the clinical features, laboratory findings, histologic findings, treatment, and clinical course. Results : The mean age at the first abnormal urinalysis was $10.6{\pm}2.2$ years in the nephrotic proteinuria group and $9.6{\pm}3.2$ years in the non-nephrotic proteinuria group. The mean age at the time of kidney biopsy was $11.3{\pm}2.3$ years in the nephrotic range proteinuria group and $10.4{\pm}3.2$ years in the non-nephrotic proteinuria group respectively. There was no significant difference in the mean age and sex between the two groups. In the nephrotic proteinuria group, 6 children had a low plasma C3 level and in the non-nephrotic proteinuria group, 8 children had a low plasma C3 level, but there was no significant difference between the 2 groups. There was no significant difference in the laboratory test results(including WBC count, RBC count, platelet count and other serologic tests) between the 2 groups except for 24 hour urine protein secretion. There was no difference between the 2 groups with regard to the acute and chronic changes in the glomerulus on light microscopic findings, IgG, IgA, Ig M, C1q, C3, C4, fibrogen deposition on immunofluoroscence findings, and mesangial deposits, subendothelial deposits, and subepithelial deposits on electron microscopic findings. The children were treated with corticosteroids, ACE(angiotensin-converting enzyme) inhibitors, dipyridamole and other immunosuppressive agents. During the course of treatment, there were no children whose clinical condition worsened. Among 19 children, 3 children went into remission(2 in the nephrotic proteinuria group, 1 in the non-nephrotic proteinuria group) and 9 children went into a partial remission(4 in the nephrotic proteinuria group, 5 in the non-nephrotic proteinuria group) on urinalysis. There was no significant difference in the treatment results between the two groups. Conclusion : The 73.7% of children who were incidentally diagnosed with MPGN by the school urine screening program had reduced C3. 42.1% of the children had nephrotic range proteinuria. There were no significant differences in clinical features, laboratory test results, light microscopic, immunofluorescence microscopic, and electron microscopic findings between the nephrotic proteinuria group and the non-nephrotic proteinuria group except for the 24 hour urine protein secretion. Therefore, for early detection of MPGN during the school urine screening program, we strongly recommend a kidney biopsy if children have abnormal urine findings such as persistent proteinuria and persistent hematuria, or if the serum C3 is reduced.

  • PDF

Evaluation of Treatment Efficencies of Pollutants in Juksancheon Constructed Wetlands for Treating Non-point Source Pollution (비점오염원 저감을 위한 죽산천 인공습지의 오염물질 정화효율 평가)

  • Choi, Ik-Won;Seo, Dong-Cheol;Kang, Se-Won;Lee, Sang-Gyu;Seo, Young-Jin;Lim, Byung-Jin;Park, Jong-Hwan;Kim, Kap-Soon;Heo, Jong-Soo;Cho, Ju-Sik
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.45 no.4
    • /
    • pp.642-648
    • /
    • 2012
  • To evaluate the water quality in Juksancheon constructed wetlands for treating non-point source pollution, the removal rates of nutrients in water and the total amounts of T-N and T-P uptakes by water plants were investigated. Chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), SS (Suspended Solids), T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were -10, 51, 66, -3 and 5%, respectively. The maximum amount of T-N uptake by water plants in August was $368.7mg\;plant^{-1}$ in the $2^{nd}$ treatment stage by Nymphoides peltata, $1314.6mg\;plant^{-1}$ in the $3^{rd}$ treatment stage by Iris pseudacorus, $1160.4mg\;plant^{-1}$ in the $4^{th}$ treatment stage by Nymphaea tetragona GEORGI, respectively. The maximum amount of T-P uptake by water plants in August was $121.7mg\;plant^{-1}$ by Nymphoides peltata in the $2^{nd}$ treatment stage, $268.7mg\;plant^{-1}$ by Iris pseudacorus in the $3^{rd}$ treatment stage and $212.0mg\;plant^{-1}$ by Nymphaea tetragona GEORGI in the $4^{th}$ treatment stage, respectively. Organic matter contents in sediments were not different. Contents of T-N and T-P in sediments were higher in spring. Microbial biomass C:N:P ratios in sediments in spring, summer, autumn and winter were 117~140:1~4:1, 86~126:5~6:1, 68~101:2~6:1 and 47~138:2~4:1, respectively. We could conclude that Juksancheon constructed wetlands show high removal efficiencies of COD and SS. However, improvements of management in winter season should be considered to improve the removal efficiencies of pollutants.

Effect of Temperature on Survival of Salmonella enterica and Staphylococcus aureus (퇴비에서 온도조건에 따른 Salmonella enterica와 Staphylococcus aureus의 내열성 변화)

  • Jung, Kyu-Seok;Heu, Sung-Gi;Roh, Eun-Jung;Jang, Mee-Na;Lee, Dong-Hwan;Choi, Jae-Hyuk;Lee, Sun-Young;Yun, Jong-Chul;Kim, Kye-Hoon
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.45 no.4
    • /
    • pp.555-559
    • /
    • 2012
  • Manures contain a variety of pathogenic microorganisms that pose a risk to human or animal. On-farm contaminations through contaminated manure were considered likely sources of the pathogen for several outbreak. Pathogenic microorganisms may survive in low numbers during the composting process and subsequently regrow to high levels under favorable conditions. The objective of this study was to investigate effect of temperature on survival of Salmonella enterica and Staphylococcus aureus in livestock manure compost. Commercial livestock manure compost (manure 60%, sawdust 40%) was inoculated with S. enterica and S. aureus. Compost was incubated at four different temperatures (10, 25, 35, and $55^{\circ}C$) for 20 weeks. Samples were taken every week during incubation depending on the given conditions. S. enterica persisted for up to 1 day in livestock manure compost at $55^{\circ}C$, over 140 days at $10^{\circ}C$, 140 days at $25^{\circ}C$, and 70 days at $35^{\circ}C$, respectively. S. aureus persisted for up to 1 day in livestock manure compost at $55^{\circ}C$ and 90 days at $10^{\circ}C$, 70 days at $25^{\circ}C$, and 40 days at $35^{\circ}C$, respectively. The results indicate that S. enterica and S. aureus persisted longer under low temperature condition. S. enterica survived longer than S. aureus at three different temperatures (10, 25, and $35^{\circ}C$). This study will provide useful and practical guidelines to applicators of soil in deciding appropriate handling and time frames for land application of livestock manure compost for sustainable agriculture. Results from these studies provide useful information in identifying manure handling practices to reduce the risk of S. enterica and S. aureus transmission to fresh produce.

Applications of Different Types of Germanium Compounds on Rice Plant Growth and its Ge Uptake (게르마늄 종류별 토양처리시 벼의 생육특성 및 게르마늄 흡수에 미치는 영향)

  • Seo, Dong-Cheol;Cheon, Yeong-Seok;Park, Seong-Kyu;Park, Jong-Hwan;Kim, Ah-Reum;Lee, Won-Gyu;Lee, Seong-Tae;Lee, Young-Han;Cho, Ju-Sik;Heo, Jong-Soo
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.43 no.2
    • /
    • pp.166-173
    • /
    • 2010
  • In order to obtain the basic information for agricultural utilization of germanium (Ge), the growth characteristics, Ge uptake, and grain quality of rice plant (Hopyungbyeo) were investigated under different germanium ($GeO_2$, and commercial Ge) treatments in paddy field. Phytotoxicity was detected in $GeO_2$ treatment but not in commercial Ge treatment. The grain yield was greater in the order of control treatment > commercial Ge treatment > $GeO_2$ treatment. The dry weight was greater in order of control treatment > $GeO_2$ treatment ${\geq}$ commercial Ge treatment. The Ge content of leaf in $GeO_2$ treatment was 6 times (177 mg $m^{-2}$) higher than that in commercial Ge treatment. The Ge content in rice bran was not different in $GeO_2$, and commercial Ge treatments. The Ge contents of brown rice in$GeO_2$, and commercial treatments were 40.9, and 31.1 mg $kg^{-1}$, respectively. The Ge uptake rates in rice plant was higher in the order of leaf > rice bran > brown rice > stem > root. Under $GeO_2$, 15.56% of Ge absorbed into plant with 11.1% in leaf, 1.6% in stem, 0.03% in root, 2.2% in rice bran and 0.73% in brown rice. Under commercial Ge treatment, 5.19% of Ge absorbed into plant with 1.8% in leaf, 0.46% in stem, 0,01% in root, 2.2% in rice bran, and 0.71% in brown rice. Based on these results, the Ge contents in polished rice in commercial Ge treatment were higher than those in $GeO_2$ treatment. However, the Ge contents of rice grain (containing rice bran and polished rice) in $GeO_2$ treatment were higher than those in commercial Ge treatment.

Metal 첨가물질에 따른 비정질 IGZO 투명전극 특성 연구

  • Sin, Han-Jae;Hwang, Do-Yeon;Lee, Jeong-Hwan;Lee, Dong-Ik;Park, Seong-Eun;Park, Jae-Seong;Kim, Seong-Jin;Lee, Yeong-Ju;Seo, Chang-Taek
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.02a
    • /
    • pp.368-370
    • /
    • 2013
  • 투명 전극은 전기전도도를 갖는 동시에 가시광선을 투과하는 소재를 말하며, 구체적으로는 빛의 파장이 400~700 nm 영역대의 가시광선을 80% 이상 투과하며 전기전도도가 비저항으로 $10^{-3}{\Omega}cm$이하이거나 면저항이 $10^3{\Omega}$/${\Box}$소재를 의미한다. 투명 전극은 전기전도도에 따라 사용되는 용도가 다양하다. LCD, PDP, OLED 와 같은 평판디스플레이 및 3D 디스플레이의 투명전극으로 사용되는 핵심재료일 뿐만 아니라 터치스크린, 투명필름, 대전방지막, 열반사막, EMI 방지막, 태양전지 분야에 광범위하게 이용되고 있다. 일반적으로, 투명전극 박막에 가장 많이 사용되고 있는 소재는 ITO (indium tin oxide)이나, 주성분인 In의 사용량 증가로 상용 ITO 타겟 가격이 급등하고 있음으며, 고가의 ITO 타겟을 대체하기 위한 저가의 투명전극 소재 개발이 절대적으로 요구되며, 신규 소재 개발을 통한 기술력 우위 선점이 필수적으로 요구되는 상황이다. 본 연구에서는 기존에 디스플레이 분야에서 널리 활용되는 고가의 ITO를 대체하기 위한 다성분 금속산화물 투명전극 스퍼터링 타겟 제조기술을 개발하기 위한 연구로서, Metal이 첨가된 In-Ga-Zn-O기반의 3성분계 투명도전성 소재를 조성설계, 고밀도 균질 타겟 제조 및 투명전극 박막을 형성하는 연구를 실시하였다. 고체산화물 산화인듐(In2O3)분말, 산화갈륨(Ga2O3) 분말그리고 산화아연(ZnO)분말과 Metal을 몰비로 칭량한 후 분말을 폴리에틸렌제 포트에 넣고 에탄올을 충분히 채운 후 지르코니아(ZrO2) 볼(ball)을 이용하여 24 h 동안 볼 밀링(ball milling) 방법으로 혼합한 뒤, $120^{\circ}C$의 플레이트위에서 마그네틱 바로 stirring하면서 건조하였다. 이 분말을 건조기에서 완전히 건조한 후 알루미나 유발을 이용해서 pulverizing한 후 sieving기를 이용하여 분말의 조립화를 하였다. 이 분말을 금형에 넣고 300 kg/$cm^2$의 압력으로 press하여 성형한 뒤 대기중에서 소결하였다 소결을 위한 승온 온도는 $10^{\circ}C$/min이었고 소결은 $1,450^{\circ}C$에서 6 h 동안 하였다. IGZO target의 조성 비율은 1:1:12 (mol%)를 사용하였으며, 첨가한 Metal은 Boron (B), Germanium (Ge), Barium (Ba)을 사용하여 타겟을 제작하였다. M-IGZO 박막은RF magnetron Sputter를 이용하여 증착하였으며, 앞선 실험에서 제작한 타겟을 사용하여 M-IGZO박막을 투명전극으로 사용하기 위한 각각의 특성을 파악하였다. 모든 박막은 상온에서 증착을 하였으며, 증착된 박막두께를 측정하기 위해 ${\alpha}$-step IQ를 사용하였고, 광학적 특성을 분석하기 위해 UV-Visible spectrophotometer 로 투과율을 측정하였다. 그리고 전기적 특성을 측정하기 위해 Hall effect measurement 및 4-probe를 사용하였으며, 결정성 분석을 위하여 XRD를 이용하여 분석하였다. 표1은 M-IGZO타겟을 사용하여 증착시간에 따른 면저항 특성을 나타내었다. Ge, B, Ba이 첨가된 IGZO 박막은 증착시간이 증가할수록 면저항이 낮아짐을 알 수 있었다. 또한, Ge이 첨가된 IGZO 박막이 다른 금속이 첨가된 IGZO 박막의 면저항보다 현저히 낮음을 알 수 있었다. Fig. 1(a), (b), (c)는 각 타겟을 동일한 조건으로 증착을 하여 광학적특성을 나타내는 그래프이다. GZO 박막의 광학적 특성을 보면 가시광 영역에서 평균 투과율은 모두 80% 이상으로 우수한 광투과 특성을 보여 투명전자소자로 사용가능하다. 특히, 자외선 영역을 모두 차단하는 UV cut 능력이 우수함을 알 수 있었다. 따라서, 금속이 첨가된 IGZO 박막을 태양전지용 투명전극으로 사용할 경우, 자외선에 의하여 수명이 단축되는 현상을 줄여줄 수 있음을 기대할 수 있으며 내구성 향상에 크게 기여할 것으로 보인다. Fig. 2는 Ge=0, 0.5, 5%인 IGZO 투명전극을 총 40회 반복하여 증착을 실시한 후 각각의 면저항을 측정한 결과이다. 실험결과에 따르면 Ge가 0%, 5%인 IGZO 투명전극은 증착을 거듭할수록 면저항이 증가하는 결과를 나타내었으며, 0.5%인 IGZO 투명전극은 점차 안정화되어가는 결과를 나타내었다. 따라서 안정화 되었을 때 평균 면저항은 26ohm/sq.로 나타났으며, 광투과율은 Fig. 3과 같이 가시광영역에서 평균 80%이상의 결과를 보였으며, 550 nm에서는 86.36%의 우수한 특성을 나타내었다. 본 연구에서는 Metal이 첨가된 In-Ga-Zn-O기반의 3성분계 투명도전성 소재 target을 제작하여 RF magnetron sputter로 박막을 형성한 후 특성을 비교하였다. M-IGZO target 중 Ge (0.5%)을 첨가한 IGZO 타겟을 사용한 투명전극이 가장 우수한 특성을 보였으며, 제작된 M-target의 In 비율이 30% 정도로 기존의 ITO (90%) 대비하여 투명전극 제작 단가를 절감할 수 있다.

  • PDF

Factors Influencing on the Cognitive Function in Type 2 Diabetics (2형 당뇨병 환자의 인지 기능에 영향 미치는 인자)

  • Goh, Dong Hwan;Cheon, Jin Sook;Choi, Young Sik;Kim, Ho Chan;Oh, Byoung Hoon
    • Korean Journal of Psychosomatic Medicine
    • /
    • v.26 no.1
    • /
    • pp.59-67
    • /
    • 2018
  • Objectives : The aims of this study were to know the frequency and the nature of cognitive dysfunction in type 2 diabetics, and to reveal influencing variables on it. Methods : From eighty type 2 diabetics (42 males and 38 females), demographic and clinical data were obtained by structured interviews. Cognitive functions were measured using the MMSE-K (Korean Version of the Mini-Mental State Examination) and the Korean Version of the Montreal Cognitive Assessment (MoCA-K) tests. Severity of depression was evaluated by the Korean Version of the Hamilton Depression Rating Scale (K-HDRS). Results : 1) Among eighty type 2 diabetics, 13.75% were below 24 on the MMSE-K, while 38.8% were below 22 on the MoCA-K. 2) The total scores and subtest scores of the MoCA-K including visuospatial/ executive, attention, language, delayed recall and orientation were significantly lower in type 2 diabetics with cognitive dysfunction (N=31) than those without cognitive dysfunction (N=49) (p<0.001, respectively). 3) There were significant difference between type 2 diabetics with and those without cognitive dysfunction in age, education, economic status, body mass index, duration of diabetes, total scores of the K-HDRS, the MMSE-K and the MoCA-K (p<0.05, respectively). 4) The total scores of the MoCA-K had significant correlation with age, education, body mass index, family history of diabetes, duration of diabetes, total scores of the K-HDRS (p<0.05, respectively). 5) The risks of cognitive dysfunction in type 2 diabetics were significantly influenced by sex, education, fasting plasma glucose and depression. Conclusions : The cognitive dysfunction in type 2 diabetics seemed to be related to multiple factors. Therefore, more comprehensive biopsychosocial approaches needed for diagnosis and management of type 2 diabetes.

Measurement of Terminal Velocity for Scatter Prevention of Powder in the Voloxidizer for Oxidation of UO$_{2}$ Pellet (UO$_{2}$ 펠릿 산화로의 분말 비산 방지를 위한 최종속도 측정)

  • Kim Young-Hwan;Yoon Ji-Sup;Jung Jae-Hoo;Jin Jae-Hyun;Hong Dong-Hee
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
    • /
    • v.3 no.2
    • /
    • pp.77-84
    • /
    • 2005
  • A voloxidizer for a hot cell demonstration, that handles spent fuels of a high radiation level in a limited space should be small and spent fuel powders should not be dispersed out of the equipment involved. In this study a density rate equation as well as the Stokes'equation has been proposed in order to obtain the theoretical terminal velocity of powders. The terminal velocity of U$_{3}$O$_{8}$ has been predicted by using the terminal velocity of SiO$_{2}$, and then determination has been the optimum air flow rate which is able to prevent powders from scattering. An equation which has shown a relationship between theoretical terminal velocities of U$_{3}$O$_{8}$ and SiO$_{2}$ has been derived with the help of the Stokes'equation, and then an experimental verification made for the theoretical Stokes' equation of SiO$_{2}$ by means of an experimental device made of acryl. The theoretical terminal velocity based on the proposed density rate equation has been verified by detecting U$_{3}$O$_{8}$ powders in a filter installed in the mock-up voloxidizer. As the results, the optimum air flow rates seem to be 20 LPM by the Stokes'equation while they are 14.5 L/min by the density rate equation. At the experiments with the mock-up voloxidizer, a trace amount of U$_{3}$O$_{8}$ seems to be detectable at the air flow rate of 14.5 L/min by the density rate equation, but U$_{3}$O$_{8}$ powders of 7$\mu$m diameter seem detectable at the air flow rate of 20 L/min by the Stokes'equation. It is revealed that 14.5 L/min is the optimum air flowe rate which is capable of preventing U$_{3}$O$_{8}$ powders from scattering in the UO$_{2}$ voloxidizer and the proposed density rate equation is proper to calculate the terminal velocity of U$_{3}$O$_{8}$ powders.

  • PDF