• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.611-617
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• 2008

Nowadays Plate Heat Exchanger (PHE) is widely used in different industries such as chemical, food and pharmaceutical process and refrigeration due to the efficient heat transfer performance, extreme compact design and efficient use of the construction material. In present study, discussed main conception of plate heat exchanger and applied in vacuum. PHE and aimed apply in the fresh water generator which installed in ship to desalinate seawater to fresh water use heat from engines. The experiment is proceeded to investigate the heat transfer between cold and hot fluid stream at different flow rate and supply temperature of hot fluid. Generated fresh water as outcome of the system. PHE is an important part of a condensing or evaporating system. One of common assumptions in basic heat exchanger design theory is that fluid is to be distributed uniformly at the inlet of each fluid side and throughout the core. However, in practice, flow mal-distribution is more common and can significantly reduce the heat exchanger performance. The flow and heat transfer are simulated by the k-$\varepsilon$ standard turbulence model. Moreover, the simulation contacted flow maldistribution in a PHE with 6 channels.

• 한국식품영양과학회지
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• 제30권4호
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• pp.574-578
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• 2001

담수어인 향어와 해수어인 방어의 white muscle과 red muscle로 부터 근원섬유단백질을 조제하여 생육 환경조건이 다른 어류의 근원섬유단백질간에는 어떠한 차이가 있는지에 대하여 알고자 myofibrillar protein ATPase 활성에 대한 온도의 존성과 열안정성을 실험하였다. 향어와 방어 근원섬유단백질의 기질친화도와 $V_{max}$ 값에 있어서는 향어가 방어에 비해 높은 값을 보였고, 활성에 대한 반응온도 및 반응시간에 따른 영향에 있어서는 myofibril의 경우 red muscle이 white muscle에 비해 낮은 활성을 나타냈으며, actomyosin의 경우에 있어서는 향어가 4$0^{\circ}C$에서도 활성증가를 나타낸 반면에 방어는 45$^{\circ}C$, 5$0^{\circ}C$와 같이 반응시간에 따른 활성증가를 나타내지 않았다. 그리고 일반적으로 향어가 방어보다 그리고 white muscle이 red muscle에 비해 높은 반응생성물을 나타내었다. 열안정성에 대한 열역학량(D value, Z value, )은 muscle 종류간 그리고 환경이 다른 어종간에 차이를 보였다. 향어와 방어 둘다 white muscle이 red muscle에 비해 안정하였으며, 향어 myofibrillar protein이 방어 myofibrillar protein보다 열에 안정한 값을 보여 환경조건이 열안정성에 차이를 줄 수 있는 것으로 나타났다.

• 한국식품과학회지
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• 제38권1호
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• pp.28-34
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• 2006

연구에서는 세정 및 표면살균처리 시스템을 개발 제작에 의한 세정, 표면살균처리 및 저장효과를 살펴보기 위해 치커리를 시료 로 수확후 저장기간별 품질평가를 실시하였다. 표면살균처리를 위해 오존수와 염소수를 사용한 결과 3 ppm 오존수와 염소수 100 ppm의 표면살균 처리는 미생물적 결과에서 커다란 차이를 보이지 않았으나, 두 살균수 모두 식품가공에 있어 제균력을 가지고 있음을 확인 할 수 있었다. 처리 조건을 신선편이 치커리에 적용해본 결과 저장 조건에 있어서는 $4^{\circ}C$에서 시료들은 관능적 평가에 있어서 9일까지는 양호한 상태를 보였으나, 이화학적 특성인 총비타민C와 총클로로필 함량을 시험해보았을 때, 영양소적 손실을 보였고, $10^{\circ}C$에 저장한 치커리의 경우 6일 이후 급격히 상품가치를 잃었다. 본 연구 결과를 토대로 위생적이고 안전한 최 소가공 농산물의 생산을 위하여 기계세정을 이용한 공정시간의 단축과 살균과정을 이용하여 식품 안전성의 위험이 될 수 있는 미생물의 오염을 막을 수 있고, 오존수를 이용하여 염소수 소독에 의존하고 있는 일반적인 생산과정의 중점관리로 지적되었던 사항을 개선할 수 있는 새로운 위생관리 방안으로써 이용 가치 있다고 평가된다.

• 한국농공학회지
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• 제43권5호
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• pp.93-105
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• 2001

The permeability of converter slag, replacing material of sand mat on improving soft clay foundation, was evaluated in the laboratory as well as in situ test. Effects of grain size, flow water time and aging were investigated using sea and fresh water Converter slag which has a grain size less than 10mm were submerged with fresh water and sea water. In fresh water, the coefficients of permeability in samples A and B were measured as 4.50${\times}$10$^{-2}$ cm per second and 1.20${\times}$10$^{-1}$ cm per second, respectively while as 1.88$\times$10$^{-2}$ cm per second and 3.86$\times$10$^{-1}$ cm per second in sea water. The condition of turbulent flow may exit and was experimentally certified based on the relationship of hydraulic gradient and seepage velocity. After 180 days in using sea water, the coefficients of permeability of samples A and B decreased ten times smaller than those initial values, and after that time continually decreased as for till 360 days. Finally, filling with voids in high-calcium quicklime(CaO) may result in the reduction of coefficient of permeability. In-situ coefficient of permeability however was Practically satisfactory.

• 한국균학회지
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• 제21권2호
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• pp.127-132
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• 1993

269 yeast strains were isolated from water samples collected from different sites in Minia governorate. These included 126 strains from fresh water, 108 strains from sewage and 35 strains from wastewater from sugar-cane factory. On the basis of 23 different physiological and morphological merkmals, the isolated strains were assigned to 16 species belonging to 11 genera. Total yeast cell counts as well as spectra of yeast species were highly variable in tested water. Total yeast cell counts ranged between $3.0{\times}10^3/l\;and\;1.8{\times}10^6/l$ for fresh water, $3.0{\times}10^4/l\;and\;3.0{\times}10^7/l$ for sewage and $1.5{\times}10^6/l\;and\;2.6{\times}10^7/l$ for wastewater from sugarcane factory. Debaryomyces hansenii, Rhodotorula mucilaginosa and Torulaspora delbrueckii were the dominant species in fresh water, whereas Debaryomyces hansenii, Thrichosporon beigelii, Rhodoforula mucilaginosa and Kluyveromyces marxianus were the dominant species in sewage and Saccharomyces cerevisiae, Kluyveromyces marxianus and Trichosporon beigelii were the dominant species in wastewater from sugar-cane factory. Yeast human pathogens, Trichosporon beigelii, Rhodotorula mucilaginosa and Candida albicans were encountered in water samples indicating that water in El-Minia governorate is also polluted by some pathogenic yeasts.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.754-757
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• 2009

The current concrete maturity method implemented with temperature sensors requires an extensive wiring, which is not often acceptable on construction site due to harsh working environment. Radio Frequency Identification (RFID) technology appears to provide a solution for the wiring issue because of its ability of sending data wirelessly. An RFID tag integrated with a temperature sensor and placed within fresh concrete may be able to read temperatures of concrete and transmit them to an RFID reader wirelessly in real-time. However the previous research illustrated that the RFID signal gets dispersed in liquid medium. One may speculate then whether RFID signals travel through fresh concrete with high water content. Would the tag's burying depth within fresh concrete affect its readability? The paper presents the preliminary results of our on-going investigation on the readability of RFID tags in concrete against water content and burying depth of tags.

• Journal of Advanced Marine Engineering and Technology
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• 제34권1호
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• pp.195-201
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• 2010

본 논문에서는 에너지 절감 기능을 포함한 대용량 전기추진모터용 냉각 시스템을 제안한다. 기존 시스템에서 청수, 해수 펌프 속도는 일정하며, 냉각수의 과냉각을 방지하기 위해 3-way valve으로 열교환기에 들어가는 유량을 제어하였다. 그리하여 외부 해수 온도의 변화와 관계없이 펌프의 전력 사용량은 일정하였다. 제안된 시스템은 외부 해수 온도에 따라 청수, 해수 펌프의 속도를 인버터로 제어하여 3-Way valve를 최소한으로 동작하도록 함으로써 에너지 손실을 방지한다. 본 연구에서는 제안한 시스템의 효율성을 확인하기 위해 시뮬레이션을 통하여 검증하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.223-226
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• 2002

This study is performed to investigate the influence of aggregate factor on the estimation of water content in fresh concrete. According to the results, water content is estimated higher in the case of basalt and granite aggregate than in the case of limestone because absorption water ratio of basalt and granite is large. As the replacement ratio of recycled aggregate increases, water content is estimated higher. But, after correcting absorption water ratio of aggregate, estimated water content is similar to mixture water content. Therefore, it is important to know the absorption water ratio of aggregates accurately, to estimate water content.

• 원예과학기술지
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• 제33권3호
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• pp.364-374
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• 2015

This study investigated quality changes in fresh-cut burdocks treated with hot water and anti-browning agents. The combined treatment using both heat treatment and anti-browning agents delayed the browning of burdocks, especially for those dipped in hot water and a solution of green tea extract plus NaCl. This treatment reduced the respiration rate and inhibited the growth of microorganisms more than heat treatment alone. The organoleptic quality of burdocks treated with the combined method proved to be the best according to sensory evaluation. Hence, this combined treatment using heat and anti-browning agents can enhance overall quality of processed fresh-cut root vegetables by browning inhibition and shelf-life extension.

• Journal of Advanced Marine Engineering and Technology
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• 제32권6호
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• pp.877-885
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• 2008

Steam injection heater is the most widely used method for fresh water generator throughout industry. This method is often chosen because of its simplicity. The steam bubbles condense and give up their heat to the surrounding liquid. Experimental study on steam injection heater has been performed in order to find the effect of major parameter. And conservation equation and Bernoulli obstruction theory are used for numerical simulation model of vapor flow-rate. Qualitative comparisons between simulations and measurements show a good agreement and the simulation models are thereby verified.