스티렌 현탁 중합반응에서 폭주반응 해석

박형일,신석주,이헌창,장서일,김태옥 한국산업안전학회 2002 한국안전학회지 Vol.17 No.3

The runaway reaction was analyzed experimently and theoretically at the batch styrene suspension polymerization process. In the experiments, the reaction temperature with time was measured at various experimental conditions. According to the experimental results, the risk of the runaway reaction was increased with increasing the ratio of the monomer(styrene, M) to the dispersion medium(water, W), the concentration of the initiator(BPO), and the monomer mass, respectively. And simulation results showed that the runaway reaction was significantly affected by the reaction rate constant of the propagation and that the phenomena of the runaway reaction occurred at about 70% conversion. Also, we found that the runaway reaction did not occur under the operation condition of below 0.5 for M/W, approximate 3 wt% BPO, and below 75℃ for the cooling temperature.

미소균열 탐상을 위한 자기광학소자를 이용한 비파괴탐상법의 제안과 적용

이형노,박한주,庄子 哲雄 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.2

항공기나 대형 플랜트 등의 경년구조물에 있어서 제조 및 설계 혹은 작업환경 등에 의해 발생하는 미소결함은 응력부식파괴로 이어지는 결정적인 원인으로 알려져 있다. 따라서 제조단계에서의 결함의 검출뿐만 아니라 운전개시 후에 있어서도 비파괴검사에 기초를 둔 정기적인 건전성평가가 요구된다. 특히 구조물내의 미소균열 평가는 구조 건전성 평가에 있어서 중요한 과제라 할 수 있다. 자기광학소자를 이용한 비파괴탐상법은 균열부근의 누설자속에 의한 자구 및 자벽의 변화를 이용하여 균열정보를 화상형태로 얻는다. 그러므로 빠른 탐상속도와 결과데이터 해석의 용이 그리고 실시간적으로 탐상결과를 획득할 수 있다는 장점을 지니고 있다. 본 논문은 자기광학소자를 이용한 새로운 비파괴적 탐상법을 제안하고, 본 탐상법을 이용하여 구조물에 존재하는 표면결함의 검출가능성 및 균열깊이의 평가를 실증하였다. 표면결함을 갖는 시험편과 파이프의 내면에 존재하는 피로균열을 대상으로 실험을 실시한 결과, 표면결함의 위치 및 2차원적 형상을 화상형식으로 얻을 수 있음을 증명하였다. 또한 피로시험중의 시험편을 대상으로 균열발생 및 균열진전과정을 평가를 통하여 원격탐상의 가능성을 제시하였다. Micro-defects induced by design and production failure or working environments are known as the cause of SCC(Stress Corrosion Cracking) in aged structures. Therefore, the evaluation of structural integrity based on micro-cracks is required not only a manufacturing step but also in-service term. So we introduce a new nondestructive inspection method using the magneto-optical film to detect micro-cracks. The method has some advantage such as high testing speed, real time data acquisition and the possibility of remote sensing by using of a magneto-optical film that takes advantages of the change of magnetic domains and domain walls. This paper introduces the concept of the new nondestructive inspection method using the magneto-optical film, also proves the possibility of this method as a remote testing system under oscillating load considering application on real fields by applying the method to four types of specimens.

감광제/광촉매에 의한 공기오염물질 제거

이재구,안기창,박주형,권정욱 충북대학교 첨단원예기술개발연구센터 1999 연구보고서 Vol.4 No.-

일반 주거환경 또는 재배시설 내의 공기오염물질인 농약 및 병원성 미생물을 인위적으로 제거하기 위해서 자연광 또는 인공광 조건하에서 몇몇 감광제/광촉매에 의한 광분해 촉진효과와 미생물의 살균효과 시험을 수행하였다. 광촉매로는 반도체 물질인 PC-1과 PC-2, 그리고 산화제로 사용되는 PC-3, PC-4, PC-5 및 PC-6과 감광제로 PS-7과 PS-8을 선발하였다. 그리고 시험화합물로는 유기인계 살충제인 dichlorvos와 dicarboximide계 살균제인 procymidone, 환경오염물질인 methyl tert-butyl ether (MTBE)를 선정하였고, 유해 미생물로는 Pseudomonas putida, Phytophthora capsici, Salmonella typhimurium, 및 Escherichia coli를 선정하였다. Dichlorvos의 경우에는 자연광과 인공광 조건하에서, 광촉매 무처리구에 비해 각각의 광촉매가 처리된 모든 처리구에서 4배 이상의 광분해 촉진효과를 보였으나, MTBE의 경우에는 단지 광촉매 PC-1 처리구만 이 광촉매 무처리구에 비해 약 17배 이상의 분해 촉진효과를 보였다. 또한 procymidone의 경우에도 PC-1, PC-6 및 PS-8에 의한 광분해가 약 3배 이상 촉진되었다. 공기 중의 미생물을 제거하기 위한 예비시험에서는 미생물 현탁액에 PC-1을 첨가하고 인공광을 조사함으로서 미생물의 생육이 저해됨을 확인할 수 있었다. 또한 평판배지에 도말된 Salmonella typhimurium은 광촉매 PC-1의 주변에서 미생물 생육이 저해됨을 보였다. 이상의 결과에서 볼 때, 광조건 하에서 이러한 감광제/광촉매를 이용한 기술은 농약을 비롯한 여러 환경 오염물질을 제거하여 재배시설 내의 작업자와 일반 대중의 환경오염원에 대한 노출을 예방할 수 있을 것으로 기대된다. For the artificial removal of the air pollutants such as pesticides, environmental toxicants, and pathogenic microorganisms in the greenhouse or the living environment, the accelerated photodegradation and the biocidal effects by some photosensitizers (PS)/photocatalysts (PC) were tested under the sunlight and/or artificial light. The selected photosensitizers/photocatalysts were the semiconductors (PC-1 and PC-2), the oxidizers (PC-3, PC-4, PC-5 and PC-6), the aromatic ketone (PS-7) and the aromatic amine(PS-8). The test toxic pollutants included the organophosphorus insecticide dichlorvos (DDVP), the dicarboximide fungicide procymidone, and the gasoline additive, methyl tert-butyl ether(MTBE) as the organic pollutants, and Pseudomonas putida, Phytophthora capsici, Escherichia coli and Salmonella typhimuriums as the pathogenic organisms. In the case of dichlorvos, all the photocatalysts selected showed more accelerated photodegradation than the control without photocatalyst under both the sunlight and artificial light. Whereas, only the photocatalyst PC-1 accelerated the degradation of MTBE about 17 times more than the control under both the sunlight and artificial light. Procymidone was much more degraded by the photosensitizer PS-8 and the two photocatalysts (PC-1, PC-6) than by PS-7. In the preliminary experiments to diminish the population of the microorganisms in the air, the photocatalyst-1 added to the microbial suspensions obviously inhibited the microbial growth under the artificial light. The photocatalyst-1 showed the bactericidal activity against Salmonella typhimurium spread on the nutrient broth agar medium. These results suggest that the photosensitizers/ photocatalysts under the light can remove some air pollutants and hence they can be used to reduce the exposure of the workers in the horticultural facilities and/or the public in the environment to the harmful pollutants.

자연정화공법에 의한 하수처리장에서 최적 여재 선정

서동철,이홍재,조주식,박현건,김형갑,허종수 한국환경농학회 2003 한국환경농학회지 Vol.22 No.1

농어촌 등에서 소규모로 발생하는 하수를 환경친화적이고 높은 하수처리효율을 유지하면서 하수처리장의 장기간 사용을 위한 최적의 여재를 선정하기 위하며 자연정화공법을 이용한 소형하수처리장치를 호기성조 및 혐기성조로 구분하여 시공한 다음, 하수처리량 및 여재 입경별 수처리 효율을 조사하였고, 호기성조와 혐기성조에서 여재 입경별 하수의 투수속도를 조사한 결과는 다음과 같다. 호기성조 처리수 및 방류수중의 pH 및 EC는 여제입경에 따라서 별 차이가 없었고, 용존산소는 호기성조를 동과한 호기성조 처리수의 용존산소는 큰 폭으로 증가하였으나 혐기성조를 통과한 방류수의 용존산소는 호기성조 처리수에 비해 약간 감소하여 여재입경 및 하수처리량에 따라서 별 차이가 없이 약 2.4~5.1 mg/L정도이었다. BOD,000 및 탁도 처리율은 여재 대(4~10 mm)를 사용했을 경우에도 호기성조 처리수에서 BOD 처리율은 약 91%이상, COD 처리율은 73%이상, 탁도 처리율은 83%이상이었으며, 이들 처리율은 여재입경이 작을수록 증가하였고 모든 조건에서 방류수중의 BOD 처리율은 98%이상, COD 처리율은 91%이상, 탁도 처리율은 98%이상이었다. 여재입경별 총 질소 및 총 인 처리율은 여재입경이 작을수록 약간 증가하였고, 모든 조건에서 방류수중의 총 질소 처리율은 약 45~59%, 총 인 처리율은 약 80~96% 정도이었다. 하수 처리율 및 투수속도를 고려해 볼 때 하수처리장 호기성조의 최적입경은 2~4 mm정도 혐기성조의 최적입경은 0.1~4 mm정도가 적절한 젓으로 사료되었다. 따라서 이러한 조건을 자연정화공법을 이용한 하수처리장에 적용하면 높은 하수처리효율을 유지하면서 하수처리장의 공극폐쇄현상이 일어나지 않아 장기간 운전할 수 있을 것으로 판단된다. An investigation was carried out to evaluate the effects of pebble size on the small-scale sewage treatment apparatus by natural purification method that consisted of aerobic and anaerobic plot pH and EC in both plots varied minimally regardless of pebble size. DO in aerobic plot increased as the pebble size decreased. That in the anaerobic plot was slightly less in comparison with that of the aerobic plot, but varied minimally, 2.4~5.1 mg/L regardless of pebble size. Under all experimental conditions, removals of BOD, COD and turbidity in anaerobic plot were more than 98, 91 and respectively. Removals of T-N and T-P increased as pebble size decreased. Under all experimental conditions, removals of T-N and T-P in anaerobic plot were about 45~59 and 80~96%, respectively. Judging from the above results, it should be considered that the optimum pebble size and pebble permeability in both plot was 2~4 mm and 0.1~4 mm, respectively.

Clean Fired-Power Plant Fuel Technology using the Waste Biomass

( Ju-hyoung Park ),( Gyu-seob Song ),( Jong Won Choi ),( Kwang Ho Song ),( Young-chan Choi ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-

Nowadays, it is widely recognized that waste biomass combustion processes can contribute to the mitigation of greenhouse gas emissions, and thus, these processes have become a viable option as an alternative energy source for the power industry. Among various waste biomasses, the herbaceous biomass is regarded as an abundant and relatively inexpensive fuel. However, it contains high ashes (especially high levels of alkali metals such as potassium and sodium et al.), leading to operation troubles such as slagging and fouling inside a heat exchanger or deterioration in efficiency. In this study, we proposed an acetic-acidbased pretreatment method to extract the alkali minerals inside herbaceous biomass and investigated the effect of treatment parameters such as concentration, temperature, and residence time. The optimal pretreatment conditions for the maximum ash rejection were found to be 1.76 in pH, 60 °C in temperature and 10 min in residence time, at which the hemicellulose, cellulose, and lignin losses were minimized. Seven different waste biomasses were investigated to validate the effects of method. The Kenaf shows the total mineral rejection of 93.48%. In particular, the potassium and sodium elements in the Kenaf, which are major factors influencing fouling and slagging in a boiler, were removed up to 99.46 and 100%, respectively. Furthermore, the proposed wet treatment was more effective for waste biomass with higher surface areas.

Giant Brunner’s Gland Hamartoma of the Duodenal Bulb Presenting with Upper Gastrointestinal Bleeding and Obstruction

Ju Hyoung Lee,Kyeong Min Jo,Tae Oh Kim,Jong Ha Park,Seung hyun Park,Jae Won Jung,So Chong Hur,양성연 대한소화기내시경학회 2016 Clinical Endoscopy Vol.49 No.6

Brunner’s gland hamartomas are small benign lesions that are most commonly found in the bulb of the duodenum. They are veryuncommon, and most are found incidentally during upper gastrointestinal series or esophagogastroduodenoscopy. The lesions tendto be asymptomatic, but patients may present with symptoms of duodenal obstruction or hemorrhage secondary to ulceration. Histologically, a Brunner's gland hamartoma consists of the components of Brunner's gland cells, as well as glandular, adipose andmuscle cells. In this study, we report the case of a 30-year-old man who presented with upper gastrointestinal bleeding and obstructivesymptoms due to a giant Brunner's gland hamartoma in the duodenal bulb. The hamartoma was successfully removed by endoscopicresection. No significant complications were observed. Microscopically, the lesion was found to be entirely composed of variableBrunner's glands and adipocytes.

Rhynchosia volubilis and Beta vulgaris Modulate UV-induced Retinal Pigment Epithelial Cells Damage and Ocular Injury in Mouse

Hyoung-ju PARK,Young Chan JEONG,Seon-Young KIM,Seong Woo KANG 한국생물공학회 2016 한국생물공학회 학술대회 Vol.2016 No.10

Prediction of the Shelf-life of Chilled Foods at Various Temperatures

Park, Sae-Rom,Lee, Yu-Si,Ha, Ji-Hyoung,Park, Ki-Hwan,Lee, Sook-Yeon,Choi, Youn-Ju,Lee, Dong-Ho,Park, Sun-Hee,Ryu, Kyung,Shin, Hyoung-Soo,Bae, Dong-Ho,Kim, Ae-Jung,Ha, Sang-Do The Korean Society for Applied Biological Chemistr 2008 Applied Biological Chemistry (Appl Biol Chem) Vol.53 No.4

This study was designed to estimate the shelf-life of the popular chilled foods kimbab (rice rolled in dried laver), samgak kimbab (triangular rice rolled in dried laver), eomook (fish surimi, boiled fish paste) mook (acorn-starch jelly), and tofu (soybean curd) in large discount markets and convenience stores. Different types of chilled foods were stored at 5, 7, and 10 for 7 and 28 days, and changes in the total numbers of the aerobic bacteria were monitored. Values of 6 and 7 log cfu/g were used as the standard. Ready-to-eat foods stored at 5 showed a much longer shelf-life compared to storage at 10. The respective percentage increases in the shelf-life observed at both 7 and 5 were kimbab (70%, 171%), samgak kimbab (87%, 143%), soybean curd (46%, 95%), fish surimi (46%, 99%), and mook (45%, 87%). To reduce the microbiological contamination, storages at 7 and 5 are recommended for the increases of 45-88 and 87-171% in the shelf-life of these chilled foods.

Production of lactoferricin derivative by high cell density culture of recombinant E. coli

Hyoung-ju PARK,Gi-jeong ROH,Eun-hye PARK,Hyune Hwan LEE,Seong Woo KANG 한국생물공학회 2017 한국생물공학회 학술대회 Vol.2017 No.10

Decline in non-smoking workers’ urine cotinine levels after increased smoking regulation in Korea

Ju-Hyoung Park,Chae-Kwan Lee,Se-Yeong Kim,Chunhui Suh,Kun-Hyung Kim,Jeong-Ho Kim,Byung-Chul Son,Jong-Tae Lee,Seung-Do Yu,Wookhee Choi,Hosub Im 대한직업환경의학회 2015 대한직업환경의학회지 Vol.27 No.-

Objectives: To identify any association between implementing smoking regulation policies and workers’ urine cotinine concentration levels in Korea. Methods: From the first stage of the Korean National Environmental Health Survey conducted by the National Institute of Environmental Research from 2009 to 2011, 2,475 non-smoking workers selected. We analyzed the trend in the changes of cotinine concentration in urine using the general linear model and linear regression, in various jobs as categorized by the National Center for Health Statistics (NCHS) and Korea Standard Classification of Occupations (KSCO). Results: The urine cotinine concentration tended to decrease every year (2.91 ng/ml in 2009, 2.12 ng/ml in 2010, and 1.31 ng/ml in 2011), showing a decreasing trend (P < 0.001). The total subjects’ decreased cotinine concentration in urine between 2009 and 2011 was 2.72 ng/ml (54.1 % relative decrease). The changes in each subgroup’s urine cotinine concentration ranged from 1.59 to 6.03 ng/ml (33.2 to 77.5 %). All groups except for the managerial group (n = 49), which had a small sample size, had statistically significant negative regression coefficients (p < 0.05). The ranges of the decrease in urine cotinine were 2.75 ng/ml (53.6 %) for males and 2.72 ng/ml (54.9 %) for females. The negative slope in urine cotinine level was statistically significantly greater in men than women. The changes in urine cotinine by occupation as classified by the NCHS occupational categories ranged from 2.43 to 3.36 ng/ml (46.6 to 61.5 % relative decrease). The negative slopes in urine cotinine levels of the white-collar and farm workers were statistically significantly greater than those of the service workers and blue-collar workers. The change by occupation as classified by the KSCO ranged from 1.59 to 6.03 ng/ml (a 33.2 to 77.5 % relative decrease). The negative slopes in urine cotinine levels of the professionals and related workers and clerks were statistically significantly greater than those of the service workers and plant and machine operators and assemblers. Conclusions: The cotinine concentration in urine among non-smoking worker groups tended to decline from 2009 to 2011. Such a result may be an indirect indicator of the effectiveness of smoking regulation policies including the revision of the National Health Promotion Act.