• Journal of Advanced Marine Engineering and Technology
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• 제35권8호
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• pp.1001-1008
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• 2011

본 논문은 내부 열교환기를 가지는 R744와 R404A용 캐스케이드 냉동시스템의 운전변수에 대한 최적의 설계를 위해서 냉동장치의 성능과 엑서지를 이론적으로 분석하였다. 본 연구에서 고려된 작동변수로는 과열도와 과냉각도, 내부 열교환기와 압축기 효율, 증발 및 응축온도 등이다. 분석한 결과를 요약하면 다음과 같다. 캐스케이드 증발온도가 증가할수록 R404A용 고온사이클의 COP는 증가하는 반면에, R744용 저온사이클의 COP는 감소한다. 따라서 이러한 이유로 전체 캐스케이드 냉동사이클의 COP는 거의 일정하다. 또한 캐스케이드 증발온도가 증가할수록 R404A용 응축기와 압축기의 엑서지 손실이 가장 큰 것을 알 수 있다. 따라서 R744와 R404A용 캐스케이드 냉동시스템의 COP 향상을 위해서는 R404용 응축기와 압축이의 엑서지 손실을 줄여야만 한다.

• 한국축산시설환경학회지
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• 제8권2호
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• pp.119-124
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• 2002

To evaluate composting process of piggery slurry, we made $1m^3$ bench scale composting reactor, and investigated the input and output of mass, moisture evaporation, volatile solid degradation, and running cost. For 15 days experimentation the results was as followed, The quantity of sawdust used was 0.47ton(18,000won) per 1ton slurry. The amount of moisture evaporated was 16.8kg/kg VS degradated. Total evaporation and VS degradation were 24.8%, 5.7% respectably. To analysis the running cost of that, we included only two factors, sawdust cost and compost income. The compost price to sell was 63won/kg(50% of market price) it made 8,694won income to 756 won loss, but 25won/kg, it was $13,650{\sim}23,100won$ loss per 1 ton slurry in the current pig farmer's condition. This cost was $8.5{\sim}14.4%$ of pig production cost and damage strongly to pig farmers to treat it.

• 한국세라믹학회지
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• 제17권2호
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• pp.80-88
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• 1980

The sintering phenomena and piezoelectric properties of PZT ceramics of composition $Pb(Zr_{0.54} Ti_{0.46})O_3$ were investigated when a small quantity of $La_2O_3$ , $LaMnO_3$, $LaCrO_3$ were added. The unwanted chemical composition change in PZT during sinterin porces du to PbO evaporation poses a severe problem in PZt manufacturinig. It is observed tat an addition of small amount of $LaMnO_3$ to PZT markedly decreases the evaporation of PbO during sintering . The green compact of (1-x) PZT.xLaMnO3(x=0.02~0.10) could be sintered of under O2 atmosphere alone with no significant loss of PbO. The planar coupling factor kp of the sintered $0.98Pb(Zr_{0.54} Ti_{0.46})O_{3.0.02}LaMnO}3$ is similar to that of commercial PZT 6A. Microstructure investigation shows that part of sintering process of $Pb(Zr, Ti)O_3$.$LaMnO_3$ system progresses via liquid phase sintering. It is believed that the evaporation of PbO in PZT sintering is restricted by the addition of $LaMnO_3$ due to the above phenomena. Furthermore the solid solution of $LaMnO_3$ in PZT causes diffuses phase transition.

• Journal of the korean society of oceanography
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• 제37권3호
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• pp.117-124
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• 2002

Anthropogenic changes have been made to the water budget for the Mediterranean Sea as a result of river diversion projects. The decrease in freshwater inflow to the Mediterranean represents an effective increase in the overall net evaporation over the basin. Hydraulic control models for the exchange between the Mediterranean and Atlantic through the Strait of Gibraltar predict that the salinity of the Mediterranean should increase if the net evaporation over the Mediterranean increases. Increases in the salinity of the deep waters in both the western and eastern Mediterranean basins have been observed. The causes of such higher deep water salinity are attributed to increases in intermediate water salinity which are ultimately mixed down into the deep sea during wintertime buoyancy loss events. The pattern of the Mediterranean salinity increase is instructive for understanding how the water mass properties in a basin change over time as a result of anthropogenic changes.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.209-211
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• 2015

Evaporation characteristics of a single droplet of carbon nanofluids were investigated in a rapid compression machine(RCM). n-Heptane and carbon black N990 were used to synthesize the carbon nanofluids. RCM is an experimental set-up to simulate a single compression stroke of reciprocating engine. Temperature and pressure in a reaction chamber were measured during the compression stroke. After the piston reaches top dead center(TDC), temperature and pressure decreased due to the heat loss at wall. In that process, a single droplet of carbon nanofluids underwent unsteady condition. A single droplet was put at the center of reaction chamber. Thermocouple whose tip is $50{\mu}m$ was used not only to measure transient bulk temperature, but also to suspend the droplet. The picture of single droplet was taken using high speed camera with a frame rate of 500 fps. From those pictures, the droplet diameter was measured by visual basic program.

• International Journal of Industrial Entomology and Biomaterials
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• 제27권2호
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• pp.312-316
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• 2013

Caffeine is a thermogenic agent that can be used in weight loss products. In order to achieve a sustained release of caffeine, silk fibroin (SF) film was uses as carrier. It has been shown that the loading method of caffeine into SF film affected the uniform distribution of caffeine in the SF film. When caffeine was added directly into SF solution, gelation has been occurred immediately and prevented the uniform distribution of caffeine. On the other hand, caffeine was dissolved in methanol in order to load the caffeine in SF film and crystallize the SF film at the same time. However, due to the fast evaporation of methanol, caffeine was recrystallized on the surface of SF film rather than penetrating into the film. Finally, caffeine was loaded into pre-crystallized SF film and uniform distribution of caffeine could be achieved. There was an initial burst of caffeine during the first 15 min, but after that a sustained release was achieved.

• 콘크리트학회논문집
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• 제16권5호
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• pp.725-731
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• 2004

A field test program was conducted for the newly placed concrete pavement of US Interstate Highway 10 between March 26th and 28th, 2003. The test section was located between Van Horn and Sierra Blanca in Hudspeth County approximately 130 km east of El Paso, Texas. The main objective of the test was collecting moisture-related data to validate the models of effective curing thickness, evaporation rate, and moisture-based maturity. Effect of moisture loss on drying shrinkage strain was studied using additional test instrumentation.

• 한국세라믹학회지
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• 제38권2호
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• pp.137-142
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• 2001

SOFC 음극으로 쓰이는 Ni-YSZ 복합체의 제조과정 중에 생기는 조성의 변화를 관찰하였다. XRD를 이용하여 복합체 부위별로 상분석한 결과 Ni-YSZ 복합체는 소결과정이나 환원처리시 복합체 내-외부간의 조성차가 일어나며 이로 인해 전기적 물성의 불균일성이 나타난다. 복합체 조성의 불균일성 및 전기적 물성의 불균일성은 주로 복합체를 구성하는 Ni 성분의 변화에 기인했는데 소결과정이나 환원과정시 Ni 성분이 기판으로 확산해가거나 기상으로 증발해버려 Ni 손실이 생기기 때문인 것으로 나타났다. Ni 성분의 손실은 열처리 온도와 시간에 비례하여 커졌으며 이로 인해 복합체의 전기적 물성도 악화되었다.

• 한국의류학회지
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• 제21권7호
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• pp.1153-1161
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• 1997

The insulation provided by clothing system is usually expressed in terms of a coo units and its distribution of the body, directly affect convective, conductive, and radiant heat loss from the skin to the environment Evaporated heat loss is dependent upon fabric permeability, the amount of body surface area covered by clothing, and the pumping of air between the body and garment layers. Persons at low to medium activity levels, dressed in conventional apparel in door environments, usually do not lose a large amount of heat through evaporation. Thermal manikin technology is used to measure the resistance to heat transfer provided by clothing systems. The reciprocal of this value, 6.45 W/m2.$^{\circ}C$ is often used in calculations for convenience. The purpose of this study was to implement a research program for calculation the insulation value (clo), body surface area and basal metabolic rate of selected clothing system. The project provided for the building of an insulation data base for use in evaluating and comparing new and improved garments.

• 대한의용생체공학회:의공학회지
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• 제10권2호
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• pp.94-96
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• 1989

Explosive evaporative removal process of biological tissue by absorption of a CW laser has been simulated by using gelatin and a multimode Nd:YAG laser. Because the point of maximun temperature of laser-irradiated gelatin exists below the surface due to surface cooling, evaporation at the boiling temperature is made explosively from below the surface. The important parameters of this process are the conduction loss to laser power absorption (defined as the conduction-to-laser power parameter, Nk), the convection heat transfer at the surface to conduction loss (defined as Bi), dimensionless extinction coefficient (defined as Br.), and dimensionless irradiation time (defined as Fo). Dependence of Fo on Nk and Bi has been observed by experiment, and the results have been compared with the numerical results obtained by solving a 2-dimensional conduction equation. Fo and explosion depth (from the surface to the point of maximun temperature) are increased when Nk and Bi are increased.To find out the minimum laser power for explosive evaporative removal process, steady state analysis has been also made. The limit of Nk to induce evaporative removal, which is proportional to the inverse of the laser power, has been obtained.