• 한국수산과학회지
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• 제45권5호
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• pp.430-437
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• 2012

The effects of low temperature and starvation on the physiochemical characteristics of the muscle of the olive flounder Paralichthys olivaceus, were examined. Fish were deprived of feed for 28 days at 2, 4, 6, 8, 10, 12, and $20^{\circ}C$ in order to establish suitable conditions for live fish transportation. Throughout most of the 4 weeks of feed restriction, the physiochemical characteristics of the muscle of olive flounder were found to be dependent on the acclimation temperature. The breaking strength of muscle did not show a significant reduction during feed restriction at 2 and $4^{\circ}C$. With increasing temperatures, however, the breaking strength of muscle differed significantly according to the individual and feed restriction period (P<0.05). The moisture content in muscle acclimated at 10, 12, and $20^{\circ}C$ increased steadily over the feed-restriction period, while the crude lipid content decreased during the same period (P<0.05). At water temperatures above $2-8^{\circ}C$, no significant differences were shown during the same period. After it reached 6, 8, 10, 12, and $20^{\circ}C$, the muscle had an accumulation of lactate, and a loss of ATP. There was no change in the lactate or ATP content during the feed restriction period at 2 and $4^{\circ}C$, although there were differences among the water temperature groups. These results clearly show that temperature can have an important influence on the of muscle of physiochemical characteristics of muscle during live fish transportation.

• 방사성폐기물학회지
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• 제3권2호
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• pp.135-148
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• 2005

방사성 폐기물의 지층 처분장 건설 및 운영을 위한 개념 선정 단계에서는 폐기물 운반 및 거치뿐 아니라, 처분장의 건설/운영/폐쇄 기간 동안 지하 처분장의 작업 환경 및 위생, 안전, 그리고 처분장내의 수분 제거와 같은 향후 처분장의 환경을 위해 처분장 환기시스템에 대한 고려가 향후 처분장의 환경을 위해 반드시 필요하다. 본 논문은 동굴처분 방식의 중-저준위 처분장 및 지하 심부에 위치하게 될 고준위 처분장에 대한 환기시스템 개념설계 기준 및 요구사항에 대한 내용이다. 방사성폐기물 처분장의 환기 시스템에서 가장 주된 기본 설계 개념은 처분장 건설과 폐기물저장을 위한 작업활동을 위해 각각 독립적이고 분리된 환기시스템을 적용하여야 한다는 것이다. 본 논문에서는 방사성폐기물 처분장의 환기시스템의 설계과정에 대해 기술하고 환기회로 모델링 방법, 자연 환기, 환기 모니터링 시스템과 실시간 환기 시뮬레이션, 화재 시뮬레이션 및 비상 방재 시스템에 관한 사항도 논의하였다

• 한국방재학회 논문집
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• 제10권3호
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• pp.147-154
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• 2010

본 연구에서는 강우에 기인하는 산사태에 의한 토사발생특성을 분석하였다. 이를 위해 1차원 불포화 지하수해석을 수행하여 강우에 따른 토양수분의 거동을 추정하였으며, 무한사면해석법을 이용하여 토양수분상태에 따른 유역단위 사면안정해석을 수행하였다. 이 때, 산사태의 발생 및 파괴깊이에 영향을 주는 토양심 및 여러 식생인자들을 고려하였다. 강우사상의 특성에 따른 토사발생특성 분석 결과, 산사태에 의한 토사의 발생에는 강우강도와 강우의 시간적 군집상태가 결정적인 영향을 미친다는 것을 알 수 있었다. 극치강우에 의한 유역 내 토사발생특성 분석결과, 태풍 '루사' 시의 잔여강우량이 다른 극치사상들에 비하여 매우 크게 나타났으며, 이러한 잔여강우량이 발생된 토사의 운송에 기여하였을 것으로 파악되었다. 아울러, 소수의 극치강우에 의하여 발생한 토사량이 유역 내 전체 토사발생량의 많은 부분을 차지함을 알 수 있었다.

• 한국동물위생학회지
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• 제28권3호
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• pp.225-234
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• 2005

Egg has been considered as one of the most important food sources in both nutritionally and economically. However, because the hazards of egg flow chains' complexity from producers to consumers and the insufficiency of cold chain systems in Korea are still remained, preventive measures for egg safety should be established. This experiment was carried out to investigate the changes of egg qualify during storage in order to find out the proper storage condition and eggshell treatment. Eggs were stored at cold condition $(5^{\circ}C,\;relative\;humidity;\;RH:\;65\pm3\%)$ and room Condition $(1st: Sep\; 6\~Nov\; 15,\;2001,\; 10\~30^{\circ}C,\;RH\;41\~86\%,\;2nd;\; Dec\;13,\;2001\~Feb\;21,\;2002,\;4\~23^{\circ}C,\;RH\;36\~89\%)$ after eggshell treatment (unwashed, washed and coated egg) during'10 weeks and examined weight loss and interior quality periodically. Weight loss was in decreasing order room washed > room unwashed > cold washed > cold unwashed > room coated > cold coated egg. And, Haugh unit was decreasing order room washed > room unwashed > room coated > cold washed > cold unwashed > cold coated egg. Our findings show that both coated eggs and refrigeration reduces the rate of decline in Haugh units and egg weight. And, washed eggs had lower average Haugh units and a higher weight loss than any of the eggshell treatment in both storage conditions. Conclusively, for washing eggshell, 150 ppm of sodium hypochlorite, regular exchange and temperature control of water should be consistent and also eggs should be dried immediately after washing. Also, national guidelines for temperature and moisture of storage places, transportation and expiration data should be established to keep quality and weight loss of eggs. Storage temperature that is a critical factor in the quality and safety of eggs should be kept under 12'c and labelling of expiration date should be obligatory.

• 한국축산식품학회지
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• 제34권3호
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• pp.287-296
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• 2014

The physicochemical and functional traits for loin muscles of Hanwoo steers were compared by quality grade (QG). A total of 500 Hanwoo steers were slaughtered, their carcasses were categorized into four groups (QG 1++, 1+, 1, and 2), and the longissimus dorsi muscles were analyzed. QG 1++ group had the highest fat and lowest moisture content (p<0.05). QG 1++ showed higher $L^*$ and $b^*$ color values, higher cooking loss, and lower shear force values, compared with the other groups (p<0.05). The flavor, tenderness, juiciness, and preference scores by sensory evaluation were highly ranked for premium QG groups (1++ and 1+). Regarding the micro compounds, QG 1 and QG 2 had greater amounts of inosine monophosphate, and QG 2 had greater amounts of anserine, carnosine, and creatine, than QG 1++ (p<0.05). QG 1++ and 1+ had higher percentages of oleic acid (C18:1) than QG 2 (p<0.05). Within premium QG 1++ and 1+, the results of the nucleotides, free amino acids, dipeptides, and fatty acids did not show any distinctive differences. Hanwoo beef as determined by the current grading system was not significantly different in terms of functional components; the only significant difference was in intramuscular fat content.

• 한국축산식품학회지
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• 제33권2호
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• pp.189-197
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• 2013

This study was conducted to determine the meat quality characteristics of pork belly from 3 different two-way crossbreeds of Yorkshire${\times}$Landrace (YL), Yorkshire${\times}$Berkshire (YB), and Yorkshire${\times}$Chester White (YC), which were domesticated for Korean consumers. Twenty pigs from each crossbreed (total n=60) were randomly selected when they reached the 110-120 kg range of market weight, slaughtered, and cooled at $0^{\circ}C$ for 24 h. The pork bellies on the left side of the cooled carcasses were then sampled and analyzed. The pH of pork bellies was the lowest in YC among the crossbreds. There was no significant difference in fat content by crossbred, but YB bellies had the lowest moisture content (p<0.05). The cooking loss of YB bellies was lower than those of others (p<0.05). The TBARS values in YB was significantly higher than those of the others at 14 d. YL bellies had a higher percentage of stearic acid, oleic acid, and MUFA than the other breeds, while YB and YC had a higher percentage of myristic acid, linoleic acid, linolenic acid, and n-6 fatty acids than the YB (p<0.05). PUFA content and P/S were significantly higher in YC compared with YL. Except for arginine, the concentrations of most free amino acids were higher in YB bellies than in others, (p<0.05). Sensory evaluation scores of bellies were higher for YC than for other breeds (p<0.05).

• Journal of Biosystems Engineering
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• 제41권4호
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• pp.365-372
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• 2016

Purpose: Tea is the most frequently consumed drink worldwide, next to water. About 75% of the total world tea production includes black tea, and withering is one of the major processing steps critical for the quality of black tea. There are two types of tea withering methods: physical and chemical withering. Withering can be achieved by using tat, tunnel, drum, and trough withering systems. Of these, the trough withering system is the most commonly used. This study focuses on the different types of withering, their effect on the various quality attributes of tea, and other aspects of withering methods that affect superior quality tea. Results: During physical withering, tea shoots loose moisture content that drops from approximately 70-80% to 60-70% (wet basis). This leads to increased sap concentration in tea leaf cells, and turgid leaves become flaccid. It also prevents tea shoots from damage during maceration or rolling. During chemical withering, complex chemical compounds break down into simpler ones volatile flavor compounds, amino acids, and simple sugars are formed. Withering increases enzymatic activities as well as the concentration of caffeine. Research indicates that about 15% of chlorophyll degradation occurs during withering. It is also reported that during withering lipids break down into simpler compounds and catechin levels decrease. Improper withering can cause adverse effects on subsequent manufacturing operations, such as maceration, rolling, fermentation, drying, and tea storage. Conclusion: Freshly harvested leaves are conditioned physically and chemically for subsequent processing. There is no specified withering duration, but 14-18 h is generally considered the optimum period. Proper and even withering of tea shoots greatly depends on the standards of plucking, handling, transportation, environmental conditions, time, and temperature. Thus, to ensure consumption of high quality tea, the withering step must be monitored carefully.

• 한국항해항만학회지
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• 제27권4호
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• pp.485-489
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• 2003

우리나라 서남권에 해당하는 서해안고속도로가 통과하는 전라북도 고창지역은 점토분이 많아 내포돼 있는 황토가 많다. 황토는 수박이나 고구마 같은 작물의 재배에는 양질의 토사이지만, 도로를 구축하기 위한 노상재료로 사용하는데는 원하는 강도값을 얻기가 힘들 토사였다. 이 연구 대상구간의 지역은 절토부의 노상재료가 원하는 재료의 품질기준을 충족시키지 못하였다. 노상층의 재료 특성을 보면, ＃200번체 통과량이 25～82％정도로 지하수위가 거의 노상면과 일치하여 자연함수비 과다로 시공시 노상토의 지지력 확보가 불가능한 것으로 판단되었다. 본 연구는 이와 같이 지지력이 부족한 현장에 적절한 절토부 노상지지력의 확보방안을 수립하여 원하는 공정을 추진함으로서 보다 안전하고 튼튼한 고속도로를 건설하는데 있었다.

• 복식문화연구
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• 제30권1호
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• pp.88-101
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• 2022

Molybdenum is used in electrical contacts, industrial motors, and transportation materials due to its remarkable ability to resist heat and corrosion. It is also used to flame coat other metals. This study investigated, the thermal characteristics of the molybdenum sputtered material, such as electrical conductivity, and stealth effects on infrared thermal imaging cameras. To this end, molybdenum sputtered samples were prepared by varying the density of the base sample and the type of base materials used. Thereafter, the produced samples were evaluated for their surface state, electrical conductivity, electromagnetic field characteristics, thermal characteristics, stealth effect on infrared thermal imaging cameras, and moisture characteristics. As a result of infrared thermal imaging, the molybdenum layer was directed towards the outside air, and when the sample was a film, it demonstrated a greater stealth effect than the fabric. When the molybdenum layer was directed to the outside air, all of the molybdenum sputtering-treated samples exhibited a lower surface temperature than the "untreated sample." In addition, as a result of confirming electrical properties following the molybdenum sputtering treatment, it was determined that the film exhibited better electrical conductivity than the fabric. All samples that were subjected to molybdenum sputtering exhibited significantly reduced electromagnetic and IR transmission. As a result, the stealth effect on infrared thermal imaging cameras is considered to be a better way of interpreting heat transfer than infrared transmission. These results are expected to have future applications in high-performance smartwear, military uniforms, and medical wear.

• 열처리공학회지
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• 제36권3호
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• pp.153-160
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• 2023

The use of biogas is an industrially necessary means to achieve resource circulation. However, since biogas obtained from waste frequently causes corrosion in pipes, it is important to elucidate corrosion mechanisms of the pipes used for biogas transportation. Recently, corrosion failure occurred in a pipe which supplied for the biogas at the speed of 12.5 m/s. Pinholes and pits were found in a straight line along the seamline of the pipe. By using corrosion-damaged samples, residual thickness, microstructure, and composition of oxide film and inclusion were examined to analyze the cause of the failure. It was revealed that the thickness reduction of biogas pipe was ~0.11 mm per year. A thin sulfuric acid film was formed on the surface of the interior of a pipe due to moisture and hydrogen sulfide contained in a biogas. Near the seamline, microstructure was heterogeneous and manganese sulfide (MnS) was found. Pits were generated by micro-galvanic corrosion between the manganese sulfide and the matrix in the interior of the pipe along the seamline. In addition, microcracks formed along the grain boundaries beneath the pits revealed that hydrogen-induced cracking (HIC) also contributed to accelerating the pitting corrosion.