• Title/Summary/Keyword: boiling effect

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Blending effect of pyrolyzed fuel oil and coal tar in pitch production for artificial graphite

  • Bai, Byong Chol;Kim, Jong Gu;Kim, Ji Hong;Lee, Chul Wee;Lee, Young-Seak;Im, Ji Sun
    • Carbon letters
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    • v.25
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    • pp.78-83
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    • 2018
  • Pyrolyzed fuel oil (PFO) and coal tar was blended in the feedstock to produce pitch via thermal reaction. The blended feedstock and produced pitch were characterized to investigate the effect of the blending ratio. In the feedstock analysis, coal tar exhibited a distinct distribution in its boiling point related to the number of aromatic rings and showed higher Conradson carbon residue and aromaticity values of 26.6% and 0.67%, respectively, compared with PFO. The pitch yield changed with the blending ratio, while the softening point of the produced pitch was determined by the PFO ratio in the blends. On the other hand, the carbon yield increased with increasing coal tar ratio in the blends. This phenomenon indicated that the formation of aliphatic bridges in PFO may occur during the thermal reaction, resulting in an increased softening point. In addition, it was confirmed that the molecular weight distribution of the produced pitch was associated with the predominant feedstock in the blend.

Antioxidant and Antidiabetic Activities of Eucommia ulmoides Bark

  • Qu, Guan-Zheng;Heo, Seong-Il;Wang, Myeong-Hyeon
    • Journal of Applied Biological Chemistry
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    • v.49 no.3
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    • pp.82-85
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    • 2006
  • Eucommia ulmoides bark extracts by cold water, boiling water, 100% EtOH, 70% EtOH, 100% MeOH, 70% MeOH and $CHCl_3$ were assayed for their medicinal effects. The antioxidant activity of the extracts ranged from $IC_{50}$ 125.2 to $IC_{50}\;872.7{\mu}g/ml$ in the 1,1-diphenyl-2-picrylhydrazyl (DDPH) free radical-scavenging assay, and cold water extracts had the highest antioxidant activity. $CHCl_3$ extracts had the highest inhibitory effect on angiotensin I-converting enzyme (ACE) giving inhibition of up to 56.4% at a concentration of 1 mg/ml. Extracts in 100% EtOH had the greatest inhibitory effect on $\acute{a}-amylase$ activity ($IC_{50}=174.6{\mu}g/ml$), and 70% MeOH extracts had the greatest inhibitory effect on ${\alpha}-glucosidase$ activity ($IC_{50}=14.0{\mu}g/ml$). Taken together, these results provided the in vitro evidence on the ACE, amylase and glucosidase inhibitory actions of E. ulmoides bark that form the pharmacological basis for its antihypertensive and antidiabetic action.

Effects of Green and Taste Teas on the Growth and Vacuolating Toxin Titer of Helicobacter pylori (녹차 등의 기호차가 Helicobacter pylori의 증식 억제와 공포화 독소 역가에 미치는 영향)

  • 정양숙;강경희;장명웅
    • KSBB Journal
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    • v.16 no.2
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    • pp.163-169
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    • 2001
  • This study was undertaken to evaluate the effects of green and taste teas on the in-vitro antimicrobial activity and vacuolating toxin titer of Helicobacter pylori. Crude aqueous extracts prepared by adding 2 g of tea leaf or powder to 100 ml of boiling distilled water, and sterilized by passing through a 0.22 $mutextrm{m}$ membrane filter. Green tea, coffee, and ginger tea showed bactericidal activity on H. pylori within 3 hours. Black tea and ssangwha tea also showed bactericidal activity on H. pylori in 24 hours. Arrowroot tea show no bactericidal effect on H. pylori after 48 hours. Two fold diluted green tea and coffee decreased(1/10,000cfu) the growth of H. pylori in 24 hours, but the two fold diluted black tea, ssangwha tea, and ginger tea showed suppression effect upon of(1/10cfu) H. pylori in 24 hours. The two-fold and 10-fold diluted green tea, coffee and two-fold diluted black tea abrogated the vacuolating toxin titer of H. pylori, but the two-fold and 10-fold diluted ginger, ssangwha, ginseng, and arrowroot tea only reduced the vacuolating toxin titer of H.pylori from 1/2 to 1/8. These result suggest that green tea and coffee have effective antibacterial or bactericidal effects on H.pylori, and that they also have a neutralization effect upon the vacuolating toxin of H.pylori.

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Antioxidant Activities and the Effect of Reducing Serum Alcohol Concentration of Lentinus edodes (표고버섯의 항산화능과 알코올분해능에 미치는 영향)

  • Kim, Chae-Hyun;Jeong, Jong-Gil
    • The Korea Journal of Herbology
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    • v.24 no.4
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    • pp.159-164
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    • 2009
  • Objectives : The purpose of this study is to evaluate antioxidant activities and reducing serum alcohol concentration of extract of Lentinus edodes on the alcohol administered rats. Methods : Antioxidant effect was measured by total phenolic compound and DPPH-radical scavenging activity of extract of Lentinus edodes in vitro. Blood alcohol concentration, aldehyde concentration, malondialdehyde concentration, glutathion concentration were measured in vivo. Results : The extract of Lentinus edodes increased DPPH-radical scavenging activity dose-dependently. The water extract with boiling water showed lower antioxidant activity and phenolic content than 70% ethanol extract in vitro. Blood alcohol concentration was significantly reduced by pre-treatment of ethanol extract of Lentinus edodes. The effect was more significant than commercial product used as a positive control. Conclusions : This study suggest that Lentinus edodes can be a potential nature resource for the management of ethanol toxicity although the mechanism of action involved in the treatment remains to be explored.

Thermal-Hydraulic Analysis and Parametric Study on the Spent Fuel Pool Storage (기사용 핵연료 저장조에 대한 열수력 해석 및 관련 인자의 영향 평가)

  • Lee, Kye-Bock;Nam, Ki-Il;Park, Jong-Ryul;Lee, Sang-Keun
    • Nuclear Engineering and Technology
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    • v.26 no.1
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    • pp.19-31
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    • 1994
  • The objective of this study is to conduct a thermal-hydraulic analysis on the spent fuel pool and to evaluate a parametric effect for the thermal-hydraulic analysis of spent fuel pool. The selected parameters are the Reynolds Number and the gap flow through the oater gap between fuel cell and fuel bundle. The simplified flow network for a path of fuel cells is used to analyze the natural circulation phenomenon. In the flow network analysis, the pressure drop for each assembly from the entrance of the fuel rack to the exit of the fuel assembly is balanced by the driving head due to the density difference between the pool fluid and the average fluid in each spent fuel assembly. The governing equations ore developed using this relation. But, since the parameters(flow rate, pressure loss coefficient, decay heat, density)are coupled each other, iteration method is used to obtain the solution. For the analysis of the YGN 3&4 spent fuel rack, 12 channels are considered and the inputs such as decay heat and pressure loss coefficient are determined conservatively. The results show the thermal-hydraulic characteristics(void fraction, density, boiling height)of the YGN 3&4 spent fuel rack. There occurs small amount of boiling in the cells. Fuel cladding temperature is lower than 343.3$^{\circ}C$. The evaluation of parametric effect indicates that flow resistances by geometric effect are very sensitive to Reynolds number in the transition region and the gap flow is negligible because of the larger flow resistance in the gap flow path than in the fuel bundle.

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

Anti-Inflammatory Effects of Water Chestnut Extract on Cytokine Responses via Nuclear Factor-κB-signaling Pathway

  • Kim, Bora;Kim, Jin Eun;Choi, Byung-Kook;Kim, Hyun-Soo
    • Biomolecules & Therapeutics
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    • v.23 no.1
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    • pp.90-97
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    • 2015
  • Water chestnut (Trapa japonica Flerov.) is an annual aquatic plant. In the present study, we showed that the treatment of water chestnut extracted with boiling water resulted in a significant increase 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity and decrease the intracellular $H_2O_2$-induced accumulation of reactive oxygen species. In addition, water chestnut extract (WCE) inhibited lipopolysaccharide (LPS)-induced nitric oxide production and suppressed mRNA and protein expression of the inducible nitric oxide synthase gene. The cytokine array results showed that WCE inhibited inflammatory cytokine secretion. Also, WCE reduced tumor necrosis factor-${\alpha}$- and interleukin-6-induced nuclear factor-${\kappa}B$ activity. Furthermore, during sodium lauryl sulfate (SLS)-induced irritation of human skin, WCE reduced SLS-induced skin erythema and improved barrier regeneration. These results indicate that WCE may be a promising topical anti-inflammatory agent.

Study on Correlation of Critical Heat Flux in Spray Cooling (분무냉각에 있어서 임계열유속 상관식에 관한 연구)

  • Kim, Yeung Chan
    • Journal of ILASS-Korea
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    • v.23 no.3
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    • pp.109-113
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    • 2018
  • The critical heat flux of spray cooling were measured on the test surface of 10 mm diameter made by stainless steel. The experiments were carried out for the droplet-flow-rate of $0.00002{\sim}0.003m^3/(m^2s)$ and liquid subcooling temperature of $40{\sim}75^{\circ}C$. Experimental results showed that the critical heat flux of spray cooling increased remarkably with the increase of droplet-flow-rate. Meanwhile, the effect of liquid subcooling on critical heat flux of spray cooling appeared weakly under the present experimental conditions. In additions, correlation between the dimensionless critical heat flux and Weber number based on droplet-floe-rate was developed for experimental results.

Experimental Study on Minimum Heat Flux Point of Liquid Film Flow (액막류의 MHF 점에 관한 실험적 연구)

  • Kim, Yeung-Chan
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.208-213
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    • 2001
  • The minimum heat flux conditions are experimentally investigated for the subcooled liquid film flow on the horizontal plate. The experimental results show that the minimum heat flux point temperature becomes higher with the increase of the velocity and the subcooling of the liquid film flow. However, the effect of distance from the leading edge of the heat transfer plate on the minimum heat flux is almost negligible. Also, the experimental results show that the propagation velocity of wetting front increase with increasing the velocity and the subcooling of the liquid film flow.

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Correlation Development on Critical Power in a Spherical Narrow Gap (구형 간극에서의 임계 출력에 대한 상관식 개발)

  • Park, Rae-Joon;Ha, Kwang-Soon;Kim, Sang-Baik;Kim, Hee-Dong;Jeong, Ji-Hwan
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.235-240
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    • 2001
  • The CHFG (Critical Heat Flux in Gap) test results have been evaluated to quantify the critical power in hemispherical narrow gaps and a new correlation has been developed. The CHFG test results have shown that increases in the gap thickness and pressure lead to an increase in critical power. The pressure effect on the critical power was found to be much milder than predictions by CHF correlations of other researches. From the CHFG test results, a new correlation on critical power in the hemispherical gap has been developed using the non-dimensional parameters as follows: $$\frac{qCHF}{{\rho}g^hfg}{\cdot}4\sqrt{\frac{{\rho}_g^2}{g{\sigma}{\Delta}{\rho}}=\frac{0.1042}{1+0.1375({\rho}g/{\rho}l)^{0.21}(D/s)}$$ The developed correlation has been expanded to apply the spherical geometry using the Siemens/KWU's correlation.

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