It has been confirmed that some Trihalomethanes (THMs) suspected as carcinogens, can be formed during chlorination for water supply through the reaction of chlorine and humic substances in water. The electrochemical characteristics on activated carbon fiber filter (ACF) electrode were investigated to remove the THMs in the chlorination process of drinking water. The electrochemical removal efficiency depended on the applied voltage and flow rate. In this study, the best result showed that the removal efficiency of THMs was higher than 99%.
Reaction conditions and catalysts were investigated for direct CF3I synthesis. Optimum reaction temperature was determined by pyrolysis of CF3H and catalytic reactions. Reactions with changing oxygen concentration were performed. As a result, yield of CF3I increased with decreasing oxygen concentration. Catalytic activity was changed with the weight ratio of the used metal salts. This result was stemmed from the change in the pore size of activated carbon by the metal salts. The optimum reaction conditions were: 600℃, space velocity of 45hr-1, and with 7wt% KF/AC catalyst.
In this work, the properties as polishing wax for automobile of O/W type microemulsion containing wax, liquid paraffine and quaternaryammonium salt was investigated. The microemulsions were prepared at 96~97℃ by the phase inversion method, and polyoxyethylene(20) sorbitan monooleate (POE(20)SMO) and distearyl dimethyl ammonium chloride(D.D.A.C) as the emulsifiers were used. The mean particle size of the rnicroemulsions was about 7±0.5nm and as the properties of polishing wax, gloss increased degree, water resistant gloss degree, initial and final contact angle after water resistance were tested. The result was that the value of water resistantance and contact angle were decreased with increasing amount of POE(20)SMO and D.D.A.C., while the gloss degree values did not affected. And the rnicroemulsion blended with mono ethylene glycol(MEG) of 5~15wt% showed smaller particle size and more stable particle size distribution than without MEG. Finally, this microemulsion showed more excellent values of gloss degree, the water resistant gloss degree and contact angle, than two kinds of commercial polishing wax for automobile.
유기물과 질소를 동시에 제거하기 위하여 연속회분식으로 운전한 MBR (membrane bioreactor)시스템에서 미생물농도와 슬러지 부하량이 막오염과 미생물 활성에 미치는 영향을 살펴보았다. 막오염은 MLSS (mixed liquor suspended solid) 농도 증가에 따라 조금씩 증가하는 경향을 보였고, 그 효과는 비포기 조건보다 포기 조건에는 좀더 두드러지게 나타났다. MLSS 농도는 막오염에 직접적인 커다란 영향을 주지는 않으나, 지나치게 높은 MLSS에서 유도되는 낮은 슬러지 부하에서는 막오염이 크게 증가하는 현상이 발견되었고, 이러한 조건에서는 포기에 의한 막 세척 효과도 크게 줄어들었다. 미생물의 개별 활성도는 슬러지 부하가 감소할수록 지속적으로 감소하는 경향을 나타내었다 반응조 전체 활성도 또한 17,000 mg/L 이상의 높은 MLSS로부터 유도되는 낮은 슬러지 부하율에서는 높은 미생물 농도에도 불구하고 오히려 감소했는데 이는 기질 부족으로 인한 경쟁으로 활성도가 떨어지고, 용액의 점성 증가로 인해 산소 전달율이 저하되었기 때문이다.
Likelihood of failure for the external corrosion of carbon and low alloy steels, which affect to a risk of facilities, was analyzed quantitatively through the risk based inspection using API-581 BRD. We found that the technical module subfactor (TMSF) decreased as the inspection number increased and it increased as the Inspection effectiveness and the used year increased. In this condition, the TMSF showed high value for the case of the marine/cooling tower drift area as a corrosion driver, poor quality of coating, no insulation, and low insulation condition.
Recently, as steel structures become higher and more long-spanned, application of high-strength steels is increasing gradually. However, criteria and example for design of high-strength steel are not built up. exiting criteria for structural steels is not proper for economical design of high-strength steel. Moreover, exiting criteria will be decrease the fatigue performance of steel bridge using high-strength steel. Therefore, criterion for application of high-strength steel must be established. In this paper, the behavior of plate girder using high-strength vertical stiffeners was clarified by carrying out layer elastic-plastic finite element analysis using finite deformation theory. In order to optimize the design and construction of plate girder using high-strength vertical stiffener, criterion for application of high-strength vertical stiffener is proposed.
Almost the steel bridges are manufactured and constructed by using weld process. The welding is necessary for connecting the flange, web and stiffener of steel bridges. However, residual stress and welding deformation producted by welding is a causes of decreasing the load carrying capacity of steel bridges. therefore, it is need to consider the initial stresses by welding when design the steel bridge. However, the influence of initial stress producted by welding on load carrying capacity of steel bridges is not elucidated. In this paper, the initial stress state on the flange, web and stiffener of steel bridges are clarified by carrying out 3-dimensional non-steady heat conduction analysis and 3-dimensional thermal elastic-plastic analysis. The influence of initial stress by welding on load carrying capacity of steel bridges is clarified by carrying out 3-dimensional elastic-plastic finite element analysis using finite deformation theory.
This study aims to examine the usefulness on the Evaluation Process for the Feasibility & Priority of A Certain Public Projects. and the Methodology used AHP(Analytic Hierarchy Process) which used pairwise comparisons of the alternatives and criteria for solving discrete alternative multicriteria decision problems. In this paper, we present a similar phenomenon, rank reversal problem, when we apply the AHP to group decision making process. The problem is identified by an example problem in that the previous rank order of Public Projects choices. we also present three different methods to prevent the undesirable characteristic of the original AHP in appling to Decision Making Process.
What is the most important in articles of food is hygienic safety. Because food Is the most common thing in our everyday life, however, the importance of its hygienic safety and other many problems caused by food may be easily neglected. What is more, food is can be dangerous as much as it is directly related to human life and accidents from the same cause may have different effects on the victims according to physical and environmental differences of individuals. Thus PL action for food requires more thorough prevention and measure. Korea has been enforcing 'the Product Liability Act' since the 1<SUP>1st</SUP> of July 2002. Product Liability (PL) is liability of the manufacturer or the seller of a product to compensate for the death or injury of consumers or the loss of properties caused by the defect of the product. This study surveyed consumers' response to and the effects of the enforcement of the Product Liability Act, investigated how consumers perceived the importance of food safety and the risk of defective food based on PL standards and their experience in damage by food through a questionnaire survey, and analyzed collected data through empirical analyses (reliability analysis, factorial analysis, regression analysis and ANOVA t-test) using SPSS 10.0. Based on the results of analysis, the researcher proposed strategies for coping with the Product Liability Act in the food industry
This study investigated diagnostic skills that use meridian points and meridian which shows the signs of illness. From the text of Yeong-Chu, we tried to find out the relationship with meridian(contain meridian point) and disease. The diagnosis with the meridian, we made a study of the relationship with multiple abscess, channel disease, so-saeng-byung. The diagnosis with the meridian point, we considered that the relationship with characteristic of each meridian point, disease and diagnosis.
본 연구는 중학생을 대상으로 지속적인 음악청취가 발표불안에 미치는 영향을 밝히고자 하였다. 실험 참여자는 여중생 두 개 반을 대상으로 통제집단 33명, 실험집단 33명씩 총 66명이고, 음악처치를 받는 집단과 아무런 처치가 주어지지 않는 집단으로 나누었다. 처치 전, 처치 1주 후 및 2주 후에 자기보고식으로 이루어진 발표불안척도(SAS)와 교사의 평가로 이루어진 발표행동 평가척도(SBES)를 통하여 발표불안을 측정하였다. 결과는 음악처치를 받은 실험집단에서 발표불안이 의미 있게 감소하는 것으로 나타났다. 따라서 음악에 의한 감성 유발이 발표상황에서 받는 스트레스에 긍정적인 효과가 있었다.
These studies were carried out to improve the reproductive efficiency through embryos transfer of Hanwoo IVM/IVF embryos. Following routine IVM/IVF procedure, Oocytes and zygotes were cultured for 40 to 44 h in CR1aa medium with BSA. Then 2 to 8-cell embryos were removed the cumulus cell and were cultured in CR1aa medium containing 10% fetal bovine serum and 2.5 mM taurine in 5% O2 and 5% CO2 at 38.5℃. The fresh and frozen thawed embryos of the morulae and blastocysts cultured for 6 to 9 days in vitro were transferred into recipients. The pregnancy rates of the blastocyst produced for 6, 7, 8, and 9 days in in vitro culture were 41.9, 48.6, 57.9 and 47.4%, respectively. In the developmental stage, pregnancy rates of early blastocysts (41.7%), blastocysts (57.6%) and expanded blastocysts (50.0%) were higher than that of morulae stage (00.0%). Fresh and frozen embryos on the pregnancy rates were 48.9 and 50.0%, respectively. These results indicate that the pregnancy rate after transfer were affected on embryonic stage of in vitro embryos and in vitro culture periods.
This paper addresses a model for the transportation planning that determines the transportation cycle time and the ve-hicle Size to minimize the cost In a distribution system The vehicle routing to minimize the transportation distance of the vehicles is a
선진국일수록 서비스 산업의 비중이 큰 것은 주지의 사실이다 선진국 진입을 위해 진력하는 한국의 입장애서 신 진국 서비스 산업의 연구 및 정보는 긴요하다 이 연구는 세계 400 대 최량 기업들 중 서비스 기업들의 다양한 경영 업적들이 서비스 산업의 여러 분야와 그 하부 부문에서 어떻게 나타나고 있는지를 기술통계, 분산분석, 던칸 검정 등을 활용해 분석하였다 이로써 서비스 산업 분야에 대한 진입, 투자, 벤치마킹 등에 관해 활용할 수 있는 유의 한 결과들을