• Title/Summary/Keyword: FC-72

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Heat Transfer Characteristics of Spray Cooling Up to Critical Heat Flux on Thermoexcel-E Enhanced Surface (Thermoexcel-E 촉진 표면에서 임계 열유속까지의 분무 냉각 열전달 특성)

  • Lee, Yohan;Hong, Gwang-Wook;Lee, Jun-Soo;Jung, Dongsoo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.9
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    • pp.373-380
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    • 2016
  • Spray cooling is a technology of increasing interest for electronic cooling and other high heat flux applications. In this study, heat transfer coefficients (HTCs) and critical heat fluxes (CHFs) are measured on a smooth square flat copper heater of $9.53{\times}9.53mm$ at $36^{\circ}C$ in a pool, a smooth flat surface and Thermoexcel-E surfaces are used to see the change in HTCs and CHFs according to the surface characteristics and FC-72 is used as the working fluid. FC-72 fluid has a significant influence on heat transfer characteristics of the spray over the cooling surface. HTCs are taken from $10kW/m^2$ to critical heat flux for all surfaces. Test results with Thermoexcel-E showed that CHFs of all enhanced surface is greatly improved. It can be said that surface form affects heat transfer coefficient and critical heat flux.

Heat Transfer Characteristics of Spray Cooling up to Critical Heat Flux on a Low-fin Enhanced Surface (Low-fin 촉진 표면에서 임계 열유속까지의 분무 냉각 열전달 특성)

  • Lee, Yohan;Kang, Dong-Gyu;Jung, Dongsoo
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.9
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    • pp.522-528
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    • 2013
  • Spray cooling is a technology of increasing interest for electronic cooling and other high heat flux applications. In this study, heat transfer coefficients (HTCs) and critical heat fluxes (CHFs) were measured on a smooth square flat copper heater of $9.53{\times}9.53$ mm at $36^{\circ}C$ in a pool, with a smooth flat surface, and 26 fpi. Low-fin surfaces were used to see the change in HTCs and CHFs according to the surface characteristics, and FC-72 was used as the working fluid. FC-72 fluid had a significant influence on the heat transfer characteristics of the spray over the cooling surface. HTCs were taken from 10 $kW/m^2$ to critical heat flux, for all surfaces. Test results with Low-fin showed that the CHFs of all the enhanced surface were greatly improved. It can be said that the surface form affects the heat transfer coefficient and critical heat flux.

목탁액의 첨가.급여가 산란계의 생산성에 미치는 영향

  • 이홍룡;김상호;박수영;류경선
    • Proceedings of the Korea Society of Poultry Science Conference
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    • 2000.11a
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    • pp.70-72
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    • 2000
  • The Effects of Dietary Supplemental Charcoal Extract (CE) were examined on performance of 19-week-old ISA Brown hens for 12weeks. Four hundred and fifty were randolmy assigned to 0, 0.025, 0.05, 0.075, 0.1% dietary CE, respectively with five replicates of 18 hens per pen. Basal diets contained 17.5% CP and 2,800 ME. Egg production egg weight, feed conversion(FC), and egg qualities were measured in every four weeks. Egg production and FC was slightly improved in 0.05% supplemental CE group compared to that of other treatments, but was not signhificant different. Average egg weight was significantly higher in 0.025% and 0.1% than other treatments(P<0.05). Total egg mass tended to be higher in 0.05% supplementation. Daily feed intake increased in 0.1% supplementation than the others, but was not statistically different. Eggshell breaking strength and Haugh unit were tended to be higher in 0.05% supplementation. There were no significant difference in eggshell thickness and yolk color of all treatments.

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The Convergence study on the Ego state, Interpersonal competence and problem solving ability of nursing students. (간호대학생의 자아 상태, 대인관계 유능성 및 문제해결 능력에 관한 융합연구)

  • Kim, Sangl-Nam;Kim, Young-Mi;Lee, So-Young
    • Journal of the Korea Convergence Society
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    • v.9 no.2
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    • pp.61-72
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    • 2018
  • The purpose of this study was to analyze the relationship between ego state, interpersonal competence and problem solving ability of nursing students. The method of this study was survay study 311 nursing students who have clinical experience. Data was collected by structured questionnaire and analyzed by SPSS / Win 21.0 program. The results showed that there was a positive correlation with the critical parent ego state(CP), nurturing parent ego state(NP), adult ego state(A), free child ego state(FC), interpersonal competence and problem solving ability. Adaptive Child ego state(AC) showed negative correlation between interpersonal competence and problem solving ability. In order to improve interpersonal competence and problem solving ability of nursing college students, it is necessary to develop CP and NP, A, FC ego state and develop and apply mutual AC analysis program to overcome the negative characteristics of AC ego state.

Nutrition Practice to Alleviate the Adverse Effects of Stress on Laying Performance, Metabolic Profile and Egg Quality in Peak Producing Hens: II. The Probiotic Supplementation

  • Hayirli, Armagan;Esenbuga, N.;Macit, M.;Yoruk, M.A.;Yildiz, A.;Karaca, H.
    • Asian-Australasian Journal of Animal Sciences
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    • v.18 no.12
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    • pp.1752-1760
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    • 2005
  • In this experiment, the effects of cage density (CD) and probiotic supplementation (PS) on laying performance, metabolic profile, and egg quality in peak-producing hens were evaluated. After blocking according to the cage location, Lohman layers (n = 180, 46 wks of age) were allocated randomly to two levels of CD (540 vs. 360 $cm^2$/hen) and three levels of PS (0, 0.15, and 0.30%). Probiotic contained Enterococcus faecium culture (10${\times}$10$^9$ cfu/g). Egg production (EP) and feed consumption (FC) were measured daily; egg weight (EW) was measured bi-weekly; BW was measured before and after the experiment; and blood samples were obtained at the end of the experiment. The data were analyzed using two-way ANOVA. Increasing CD decreased FC (125.0 vs. 120.8 g/d, p<0.0001) and FCR (1.93 vs. 1.87, p<0.0001) and did not alter EP, EW, and BW. Increasing level of PS linearly decreased FC (p<0.02) and FCR (p<0.006). Averages were 123.9, 123.2, and 121.6 g/d for FC and 1.91, 1.92, and 1.86 for FCR in hens supplemented with 0, 0.15, and 0.30% probiotic, respectively. Hens placed in high-density cages had greater serum corticosterone concentration than hens placed in normal-density cages (12.8 vs. 11.3 $\mu$g/dL, p<0.04); CD did not affect concentrations of other metabolites. Increasing level of PS linearly increased serum glucose, albumin, and creatine concentrations and quadratically increased total protein, globulin, Ca, and P concentrations. Average concentrations (mg/dL) were 260, 297, and 305 for glucose; 6.28, 8.09, and 7.58 for total protein; 1.98, 2.48, and 2.38 for albumin; 4.30, 5.62, and 5.19 for globulin; 0.40, 0.52, and 0.54 for creatine; 16.0, 16.5, and 16.3 for Ca; and 6.27, 8.14, and 7.17 for P in hens supplemented with 0, 0.15, and 0.30% probiotic, respectively. There was no effect of CD on egg quality. Increasing level of PS linearly improved yolk color (YC) and quadratically increased albumen index (AI) and Haugh unit (HU). The mean values were 9.67, 9.75, and 10.58 for YC; 8.94, 6.93, and 8.72% for AI; and 85.6, 74.9, and 82.9 for HU for hens supplemented with 0, 0.15, and 0.30% probiotic, respectively. There was also CD by PS effect on FC, EP, and serum glucose, total protein, albumin, globulin, creatine, Ca and P concentrations. In conclusion, increased CD partially depressed laying performance and caused stress. Probiotic supplementation improved laying performance and metabolic profile. It also partially alleviated the adverse effects of stress resulting from increased caging density.

A Comparative Study of Hataedock versus Probiotics on Immunomodulating Effect in Intestinal Mucosa (황련감초 하태독법과 프로바이오틱스의 대장점막 내 면역조절 효과 비교연구)

  • Ahn, Sang Hyun;Cha, Ho Yeol;Kim, Ki Bong
    • The Journal of Pediatrics of Korean Medicine
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    • v.31 no.2
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    • pp.48-56
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    • 2017
  • Objectives Hataedock is a treatment that dispels toxic heat and meconium which has been accumulated to the fetus from a pregnant mother via orally administering herbal extracts to a newborn baby. This study was conducted to compare the efficacy of Hataedock, with using the extract of Coptis japonica & Glycyrrhiza uralensis, to the early administration of probiotics for immunomodulation in the intestinal mucosa. Methods NC/Nga mice were divided into three groups; Control group (no treatment), CGT group (3-week-old mice given the extract of Coptis japonica & Glycyrrhiza uralensis), and MBT group (3-week-old mice given a Bifidobacterium). After 2 weeks, the intestinal mucosa tissues of each group of mice were observed. Immunohistochemical staining for IL-4, IL-13, CD40, $Fc{\varepsilon}RI$, $p-I{\kappa}B$, EGF, and VEGF in the intestinal mucosa was performed. Results CGT group showed 65% decrease in IL-4, 67% decrease in IL-13, 58% decrease in CD40, 72% decrease in $Fc{\varepsilon}RI$, 76% decrease in $p-I{\kappa}B$, 41% increase in EGF and 100% increase in VEGF compared to the control group. MBT group also showed 50% decrease in IL-4, 63% decrease in IL-13, 33% decrease in CD40, 53% decrease in $Fc{\varepsilon}RI$, 46% decrease in $p-I{\kappa}B$, 23% increase in EGF and 151% increase in VEGF compared to the control group. Conclusions These results suggest that both Hataedock, with using the extract of Coptis japonica & Glycyrrhiza uralensis, and early administration of probiotics were effective in regulating Th2, relieving inflammation and developing intestinal mucosal tissues. Hataedock with extract of Coptis japonica & Glycyrrhiza uralensis may be more effective for immunomodulation in intestinal mucosa than probiotics.

Heat Transfer Enhancement from Plain and Micro Finned Surfaces According to Liquid Subcooling (작동유체의 과냉도에 따른 매끈한 표면과 마이크로 핀 표면에서의 열전달 촉진에 관한 연구)

  • Lim, Tae-Woo;You, Sam-Sang;Choi, Hyeung-Sik
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.8
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    • pp.1137-1143
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    • 2009
  • Experiments were conducted to evaluate pool boiling heat transfer performance between plain and micro finned surfaces with FC-72, which is chemically and electrically stable. Three kinds of micro fins with the dimension of $100{\mu}m\;{\times}\;10{\mu}m$, $150{\mu}m\;{\times}\;10{\mu}m$ and $200{\mu}m\;{\times}\;10{\mu}m$ (width $\times$ height) were fabricated on the surface of a silicon chip. The experiments were carried out on the liquid subcooling of 5, 10 and 15 K under the atmospheric condition. The micro finned surface with a larger fin width of $200{\mu}m$ provided a better pool boiling heat transfer performance. Also, the micro finned surfaces showed a sharp increase in heat flux with increasing wall superheat and a larger heat transfer enhancement compared to a plain surface.

A Function-characteristic Aware Thread-mapping Strategy for an SEDA-based Message Processor in Multi-core Environments (멀티코어 환경에서 SEDA 기반 메시지 처리기의 수행함수 특성을 고려한 쓰레드 매핑 기법)

  • Kang, Heeeun;Park, Sungyong;Lee, Younjeong;Jee, Seungbae
    • Journal of KIISE
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    • v.44 no.1
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    • pp.13-20
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    • 2017
  • A message processor is server software that receives various message formats from clients, creates the corresponding threads to process them, and lastly delivers the results to the destination. Considering that each function of an SEDA-based message processor has its own characteristics such as CPU-bound or IO-bound, this paper proposes a thread-mapping strategy called "FC-TM" (function-characteristic aware thread mapping) that schedules the threads to the cores based on the function characteristics in multi-core environments. This paper assumes that message-processor functions are static in the sense that they are pre-defined when the message processor is built; therefore, we profile each function in advance and map each thread to a core using the information in order to maximize the throughput. The benchmarking results show that the throughput increased by up to a maximum of 72 % compared with the previous studies when the ratio of the IO-bound functions to the CPU-bound functions exceeds a certain percentage.

Study on flow boiling heat transfer in two-phase micro-channels heat sink (2상 마이크로 채널 히트 싱크에서의 유동 비등 열전달에 관한 연구)

  • Choi, Yong-Seok;Lim, Tae-Woo
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.7
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    • pp.702-708
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    • 2015
  • Two-phase flow boiling experiments were conducted using FC-72 as the working fluid. The micro-channels consisted of 15 channels with a depth of 0.2 mm, width of 0.45 mm, and length of 60 mm. Tests were performed over a mass flux range of $200-400kg/m^2s$, heat flux range of $5.6-49.0kW/m^2$, and vapor quality range of 0.02-0.93. Based on the results of the experiment, the heat transfer mechanism by nucleate boiling was dominant at a lower vapor quality (x<0.2), whereas that in the region of a vapor quality greater than 0.2 was complexly influenced by nucleate boiling and forced convection boiling. The nucleate boiling and forced convection boiling could be expressed as functions of the boiling number and convection number, respectively. In addition, the heat transfer coefficient obtained by the experiment was compared with the heat transfer coefficient by the existing correlation.

Heat transfer characteristic and flow pattern investigation in micro-channels during two-phase flow boiling (이상 유동 비등 시 마이크로 채널에서의 열전달 특성과 유동양식 조사)

  • Choi, Yong-Seok;Lim, Tae-Woo
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.7
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    • pp.696-701
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    • 2015
  • Two-phase flow boiling experiments were conducted in 15 micro-channels with a depth of 0.2 mm, width of 0.45 mm, and length of 60 mm. FC-72 was used as the working fluid, and the mass fluxes ranged from 200 to $400kg/m^2s$. Tests were performed over a heat flux range of $5-40kW/m^2$ and vapor quality range of 0.1-0.9. The heat transfer coefficient sharply decreased at a lower heat flux and then was kept approximately constant as the heat flux is increased. Based on the measured heat transfer data, the flow pattern was simply classified into bubbly, slug, churn, and wavy/annular flows using the existing method. In addition, these classified results were compared to the transition criterion to wavy/annular regime. However, it was found that the existing transition criterion did not satisfactorily predict the transition criterion to annular regime for the present data.