In this study, infrared thermometry techniques were used to conduct surface wetting performance tests (wicking tests) on micropillar structures with good fluid supply capabilities to enhance the critical heat flux. Wicking tests were conducted based on various micropillar shapes (i.e., diameter and spacing) to investigate the surface wetting performance near the boiling point of the fluid(~100°C). The surface temperature was increased from 20°C to 95°C, to examine the wicking performance The shape of the micropillars were quantified by the roughness and the effect of the roughness and temperature on the wicking performance was analyzed. As a result, we confirmed that the roughness of the micropillars increases the capillary pressure, improving the wicking performance. The sample D04 G10 with the highest roughness coefficient at room temperature (r=2.51) exhibited the highest wicking coefficient, showing a 170% improvement in wicking performance compared to D04G20 with the smallest roughness coefficient at room temperature(r=1.51). Additionally, the D04 G10 sample (r=2.51) recorded a 50% improvement in the wicking coefficient at the highest temperature(95°C) compared to room temperature(20°C). The wicking coefficient data will be utilized as a database for developing a new correlation for critical heat flux.
한중 조리동사는 의미의 범주가 달라 대응관계가 매우 복잡하다. 동일한 조리활동 을 가리키면서도 중국어와 한국어가 ‘일대일’의 대응관계를 보이지 않는 경우가 있다. 본 연구는 삶다(煮)류 의미장의 중국어 13개, 한국어 9개 조리동사를 대상으로 계열 관계와 결합관계를 통해 의미소를 설정하고 이들의 의미특징을 분석하여 한중 조리 동사의 대응관계를 살펴보는데 목적이 있다. 특히 사전과 코퍼스를 활용하여 다의어 에서 다수의 의미소를 설정하고 분석하는 방법과 과정을 제시함으로써 한중 조리동 사의 의미 범주 차이를 고찰하였다. 구체적인 의미자질 분석을 통해 중국어 조리동 사에서 다의성이 강하게 나타나고 의미의 범주가 크다는 결론을 내릴 수 있었다.
Double slug interaction in downward-facing nucleate boiling was studied to investigate its effect on boiling performance. Two heating surfaces were individually controlled to apply heat flux while their boiling performance were measured. A slug generated from upper heater affect on lower heater to make convectional flow by suction following departure of slug. Moreover, it showed to reduce hovering time of slug bubble on lower heater because it could help bubble departure on lower heater. Meanwhile, a slug generated from lower heater affected on upper heater to make convectional flow by sweeping. However, it showed to increase hovering time of slug bubble on upper heater, because they collapsed to each other. So, the slugs from lower heater enhanced the boiling performance of upper heater with low heat flux condition, but reduced the performance of it with high heat flux condition.
This paper reports slug bubble dynamics on modified surface with two-dimensional graphene film in downward-facing nucleate boiling. Behaviors of slug bubbles were observed with high speed camera, and post-processing was followed to measure departing speed, frequency, and diameter of slug bubbles, which were important to analyze boiling performance change. The graphene-modified surface showed enhanced boiling heat transfer coefficient (BHTC) and critical heat flux (CHF). The effect of surface modification on slug bubble dynamics was quantitatively analyzed; bigger slugs departed from the modified surface with faster speed but same frequency, compared with the bare. It seems that the BHTC enhancement is caused by increase of bubble diameter, resulting in increase of its departing speed. The higher speed of departing bubble could extend the hydrodynamic limit of vapor removal from downward-facing surface, so that CHF performance could be enhanced.
This paper reports an uncertainty analysis of quantitative visualization methodology for slug bubble dynamics in downward-facing nucleate boiling condition. Measurement of dynamics of slug bubble, i.e. departing speed, frequency, and diameter, is very important to predict safety margin of thermal systems in moving vehicle. By employing high speed visualization and post-processing, we quantitatively measured the volume and location of slug bubble, so that vapor generation rate and departing speed data were derived from their time differentiation. As a visualization methodology, its reliability was evaluated via uncertainty analysis. For 95% confidence interval, uncertainty of vapor generation rate and departing speed were 3% and 2%, respectively, and which were one order lower than standard deviation of those data.
In this study, we investigated to the heat transfer performance of coating nano-structure with various shapes and patterns on the heat transfer surface. As a result of the measurement of the 3D nano shape, it was confirmed that the roughness generally increases when the adhesive is sprayed on the coating surface and finished durability experiment. In the case of TEOS adhesive, the roughness increased by 0.074 ㎛, 0.012 ㎛ and 0.015 ㎛, and the contact angle decreased 12.64°, 1.31°, 9.84° at the coating time of 120 seconds, 180 seconds and 240 seconds, respectively. In the case of PVA adhesive, the roughness increased by 0.069 ㎛, 0.056 ㎛ and 0.03 ㎛, and the contact angle decreased 2.85°, 4.82°, 6.96° at the coating time of 120 seconds, 180 seconds and 240 seconds, respectively. In the case of DGEBF adhesive, the roughness increased by 0.042 ㎛, 0.053 ㎛ and 0 ㎛, and the contact angle decreased 0.81° at the coating time of 120 seconds, increased 4.82°, 6.96° at the coating time of 180 seconds and 240 seconds, respectively. As a result, the durability tends to decrease as more nano-structures are deposited, and 3D nano shapes, contact angles and SEM photographs showed that the performance of the PVA adhesive was superior among the three adhesives.
Potato Virus Y (PVY) (Potyviridae: potyvirus) is one of the serious emerging virus of seed potato world-wide. It affects the seed potato by transmitting non-persistently via aphids. Here, we developed a simple PVY detection method which used the boiling technique for releasing of the viral RNA from aphid such as stylet and amplification by PVY specific primers located in the viral coat protein gene which suitable for various strains. This simplified method could save the time compared to earlier detection method due to the simplified RNA extraction step. Following this procedure, we tested this one step RT-PCR based PVY detection method by using three PVY vectoring aphid species (M. persicae, A. gossypii and M. euphorbiae) as well as other sucking type insect such as thrips (F. occidentalis). This PVY detection method is rapid, easy-to-use and suitable for large-scale testing in laboratories of seed potato.
Flexible two-phase thermosyphons are devices that can transfer large amounts of heat flux with boiling and condensation of working fluid resulting from small temperature differences. A flexible two-phase thermosyphon consists of a evaporator, an insulation unit, and a condenser. The working fluid inside the evaporator is evaporated by heating the evaporator in the lower part of the flexible two-phase thermosyphon and the evaporated steam rises to the condenser in the upper part to transfer heat in response to the cooling fluid outside the tube. The resultant condensed working fluid flows downward along the inside surface of the tube due to gravity. These processes form a cycle. Using R134a refrigerant as the working fluid of a loop type flexible two-phase thermosyphon heat exchanger, an experiment was conducted to analyse changes in boiling heat transfer performances according to differences in the temperature of the oil for heating of the evaporator, the temperature variations of the refrigerant, and the mass flows. According to the results of the present study, the circulation rate of the refrigerant increased and the pressure in the evaporator also increased proportionally as the temperature of the oil in the evaporator increased. In addition, the heat transfer rate of the boiler increased as the temperature of the oil in the evaporator increased.
PURPOSES : The purpose of this paper is to evaluate the moisture susceptibility of asphalt mixtures containing developed liquid antistripping agents using the boiling water test as a screening test.
METHODS: The boiling water test was used to evaluate the moisture susceptibility of asphalt mixtures containing different anti-stripping agents. The tensile strength ratio was calculated to compare the moisture susceptibility of the asphalt mixtures after indirect strength tests were performed. Additionally, image analysis techniques were used to calculate and analyze the quantity of stripped area in the asphalt mixtures.
RESULTS: In general, the asphalt mixtures containing anti-stripping agents showed a higher resistance of anti-stripping based on the boiling water test and tensile strength ratio.
CONCLUSIONS: The boiling water test can be used to differentiate the resistance of moisture susceptibility of asphalt mixtures, except for asphalt mixtures containing hydrated lime. The boiling water test can be used as a screening test for asphalt mixtures before conducting time consuming and expensive indirect tensile strength tests.
PVY (Potyviridae: potyvirus) is one of the most important potato virus affecting seed potato production and also it is transmitted non-persistently via aphids. For healthy seed potato production, a virus detection system is highly important in addition to aphid monitoring and control. To achieve this detection method, it need to fast and easy to use. About two decades ago RT-PCR based PVY detection method was developed. However that was very time consuming and has low sensitivity. Here, we developed an advanced PVY detection method which a uses the boiling extraction of the viral RNA from aphid stylet and amplification by specific primers located in the viral capsid protein gene. Therefore, it could directly synthesize cDNA of PVY viral capsid gene from extracted RNA of PVY using one-step RT-PCR method in very short time compared to previous methods due to the omission of RNA extraction step. We confirmed this PVY detection method using the two aphid species (Macrosiphum euphorbiae and Aphis gossypii) that known as PVY vectors. The efficiency of this PVY detection method was 60% to 80% from two the aphid species. Hence, this method could be potentially applied to virus free seed potato production programs.
본 연구에서는 수문사설 에 수록된 토란병의 제조방법을 확립하기 위하여 토란의 가열 시간 및 고명에 따라 토란병을 제조하고, 품질특성을 비교․분석하였다. 가열 시간에 따른 수분, 조단백질, 조지방 및 조회분 함량은 각각 83.42~84.61%, 1.25~1.31%, 0.08~0.11%, 0.62~0.81% 범위로 조지방은 유의적 인 차이가 없었으며, 조회분은 가열처리로 인해 유의적으로 감소하였다. 토란의 주요 유리당은 fructose, glucose 및 sucrose 가 검출되었고, 가열 시간에 따라 각각 0.17~0.33%, 0.16~0.29% 및 0.26~0.38% 범위로 15분 가열처리 때까지 유의적으로 감 소하였다. 경도 역시 가열 시간이 늘어날수록 2.75 ㎏에서 0.14 ㎏까지 감소하였다. 가열 시간에 따른 관능특성을 평가한 결 과, 향과 맛은 각 처리구간 유의적인 차이를 보이지 않았고, 질감과 전반적인 기호도는 5분 처리구가 다른 처리구에 비해 유의적으로 낮게 평가되었으며, 10분 처리 이후에는 큰 차이 를 보이지 않았다. 이상의 결과, 토란병의 제조 시 가열 시간 은 10분이 바람직할 것으로 판단된다. 잣고물, 콩고물, 검은 깨고물 및 밤고물 등 고명 종류에 따른 토란병의 관능특성을 평가한 결과, 색, 향, 질감, 맛 및 전반적인 기호도는 각각 5.20~7.50, 5.40~7.70, 6.10~7.00, 6.10~7.20 및 6.20~7.60 범위 로 평가되었고, 콩고물을 묻힌 토란병이 모든 항목에서 가장 높게 평가되었다.
The reduction rate of pesticide residues on spinach(bifenthrin, metalaxyl, procymidone), chard(bifenthrin, imidacloprid) and mallow(bifenthrin, chlorpyrifos, imidacloprid) were tested on each step of washing and boiling(spinach: 1, 3, 5min., chard: 3, 6, 9min., mallow: 10, 20, 30min.). The reduction rates of bifenthrin and procymidone by washing were 58~64% and 82%, and these were not changed significantly after boiling. In case of imidacloprid, the rates showed 43% on chard and 12% on mallow by washing, and these were highly increased to 94% after boiling. And the reduction rate of metalaxyl and chloropyrifos were 69% and 11% by washing, and 96~98% and 77~79% by boiling. Specifically we monitored the pesticide residues on both boiled vegetable and its water because there are used to cook as soup in Korea. The total residual amounts of imidacloprid and chloropyrifos were effectively removed on both boiled mallow and its water (12% → 34~40%, 11% → 76~79%), however, the other tested pesticides were not changed on pesticide residues when calculated with total amounts on boiled vegetable and its water. These explained the other pesticides were just moved vegetable to water by boiling.
This study is experimentally to analyze the heat transfer characteristics and photographic observation of bubble generation in saturated nucleate pool boiling. The photographs were taken of water boiling from heated nickel wires. The attempts is made to explain the different nucleate boiling of water. Some of the bubbles photographed were very close to the spherical shape, while others were close to the hemispherical. Also, a number of bubble had intermediate shapes that were called oblate bubbles. At least, heat transfer regions of three and possibly four were found to exist in nucleate boiling depended upon the mode of vapor generation. The vapor structure on the surface progressed through a sequence of first discrete bubbles, then vapor columns and vapor mushrooms, and finally vapor paths, as the surface temperature was increased. These individual vapor structures or combinations of them determine the mechanism of heat transfer in the four nucleate boiling regions.
소뼈의 효과적인 이용을 위하여 사골뼈와 갈비뼈의 가열시간에 따른 칼슘, 인, 마그네슘, 단백질, 총 유리 아미노산, 콜라겐 등의 영양성분 측정과 관능검사를 실시한 결과는 다음과 같다. 12시간 까지 가열할 경우, 조리시간이 경과할수록 고형물, 칼슘, 인, 마그네슘, 단백질, 총 유리아미노산, 콜라겐 함량은 점점 증가하였으며 12시간 가열에서 가장 높았으며, 이와 같은 영양성분이 사골뼈 보다 갈비뼈에서 조금 높게 용출되었다. 12시간 끓인 시료에 식염 0.8%를 첨가하여 관능 검사를 실시한 결과 색, 향기, 맛, 종합적인 맛에서 갈비뼈 시료가 사골뼈 시료보다 높은 기호도를 나타냈다. 이상의 결과들로부터 사골뼈와 갈비뼈를 12시간 가열함으로써 칼슘과 마그네슘 등 영양성분이 가용화되기 쉬우며, 사골뼈와 갈비뼈의 영양성분과 맛이 우수하므로 다양한 이용과 개발을 시사하였다.
The “Film boiling” Chemical Vapor Infiltration (CVI) process is a rapid densification one developed in particular for theelaboration of carbon/carbon composite materials. In order to optimize this new thermal gradient process, we have carried outseveral studies, on one hand, about the nature of the complex chemical reactions in a confined medium, and on the other hand,relative to the role of heat and mass transfers inside the preform. We show in this study that the introduction of a permeablesheath around the preform leads to hybrid liquid/gas CVI process which presents the advantages of very high densificationrates associated with a moderate input energy.
적색장미의 변색방지 기술을 개발하고자 Al, AlK, Mg 및 CuSO4를 증류수에 0, 5, 10, 20 및 30%로 희석한 열탕(85∼90℃)에 장미 ‘카디날’ 꽃잎을 30초 동안 침지하여 건조한 후 자외선 조사에 따른 변색정도를 조사하였다. Al 용액 처리구는 a*값의 경우 5, 10% 처리구에서, b값은 20%처리구에서, △E*값은 30% 처리구에서 신선한 꽃과의 색차가 적었다. AlK 처리구는 5%와 30% 액에 처리시 신선한 꽃과의 헌트 a*, b* 및 △E*값의 차이가 적었다. Mg 처리구는 20% 및 30% 처리구에서 신선한 꽃과의 Hunter a*, b* 및 △E*값의 차이가 적었다. CuSO4 처리구는 5% 액에 처리시 신선한 꽃과의 Hunter a*, b*, △E*값 및 Munsell 표색계 H값의 차이가 적었다.
Texture is an important quality factor of processed chestnut products, which changes depending on the conditions of boiling process. The conventional boiling process consists of three stage(1st : 70 minutes at 60; 2nd : 20minutes at 70; 3rd : 80minutes at 98). To improve the conventional boiling process of processed chestnut products, we investigated the changes of texture at different stages of boiling process and undertook the optimization of boiling process by response surface method on heating times of 2nd and 3rd heating, and amount of softening agent. The initial hardness and cohesiveness, the most important textural characteristics of chestnut, were 7.876kg and 0.189, respectively. In the third boiling stage, hardness decreased to 0.313kg and cohesiveness increased to 0.310. Using response surface method the minimum point of hardness and maximum point of cohesiveness was examined and model equations for predicting the changes of hardness and cohesiveness in the optional boiling condition were developed.