• Title/Summary/Keyword: H2 absorption

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(+)-Catechin is a Potent Inhibitor of Intestinal Absorption of Cholesterol in Rats

  • Noh, Sang K.;Koo, Sung I.;Jiang, Yongzhi
    • Preventive Nutrition and Food Science
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    • v.8 no.1
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    • pp.1-6
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    • 2003
  • Catechins exhibit a hypocholesterolemic effect in cholesterol-fed animals. The present study was conducted to examine whether (+)-catechin influences the absorption of cholesterol in rats. Male Sprague-Dawley rats were fed ad libitum an AIN-93G diet containing soybean oil for 5 wk. Rats with lymph cannulae were infused at 3.0 mL/h for 8 h via a duodenal catheter with a lipid emulsion containing radiolabeled cholesterol with or without (+)-catechin. Lymph was collected hourly for 8 h. The enteral infusion of (+)-catechin significantly lowered the lymphatic absorption of $^{14}$ C-cholesterol (21.1 $\pm$ 3.6% dose/B h) compared with controls infused with the lipid emulsion devoid of (+)-catechin (38.2 $\pm$ 1.2% dose/8 h). The intestinal absorption of $\alpha$-tocopherol (24.2$\pm$3.0% dose/8 h) also was significantly decreased by (+)-catechin infusion, relative to controls (32.2$\pm$2.2% dose/8 h). However, the lymphatic outputs of oleic acid and phospholipid were not affected by enteral (+)-catechin infusion. The results indicate that (+)-catechin has a profound inhibitory effect on the intestinal absorption of cholesterol and $\alpha$-tocopherol without affecting the absorption of fat.

Characteristic Analysis of Double Effect Absorption Refrigeration Machine using $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ ($H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$를 이용한 2중 효용 흡수식 냉동기 특성해석)

  • 문춘근
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.6
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    • pp.792-799
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    • 1998
  • Further improvement of existing $H_{2}O/LiBr$ absorption refrigeration machine is absolutely neces-sary to promote the utilization of gas-cooling system Among various methods to improve the per-formance of the absorption refrigeration machine this research has focused on the use of a new working fluid that has better properties than the existing $H_{2}O/LiBr$ working fluid. In the series of the research, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ system was selected as the most promisable candidate. The absorption refrigeration machine is water-cooled double-effect, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ sys-tem with series flow type. In this study we found out the characteristic of new working solution through the cycle simulation and compared the result with that of LiBr solution to evaluate. Theoptimum designs and operating conditions were determined based on the operating constraints and the coefficient of performance. Results demonstrate that new working fluid subsrantially increases COP by as much as 10% and has a wider working range with 8% higher crystallization limits compared to the conventional $H_{2}O/LiBr$.

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Ultrasonic Absorption Measurements of Bovine Serum Albumin Solutions in the Frequency Range 200 kHz to 3 MHz (주파수 200 kHz-3 MHz영역에 대한 알부민용액의 초음파 흡수측정)

  • Bae, Jong-Rim
    • The Journal of the Acoustical Society of Korea
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    • v.25 no.1E
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    • pp.14-19
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    • 2006
  • Ultrasonic absorption and velocity spectra in bovine serum albumin (BSA) aqueous solutions have been measured at $20^{\circ}C$ over the frequency range 0.2-3 MHz in the pH range 1.5-13.2. The high-Q ultrasonic resonator and pulse-echo overlap methods were used. At acid pH's, excess absorption over that of pH 7 was explained by double relaxation. The pH dependences of the relaxation frequency and maximum absorption per wavelength, showed that the relaxation at about 200 kHz was related to the expansion of molecules and that about 3 MHz resulted from the proton transfer reaction of carboxyl group. At alkaline pH's, the excess absorption was explained by double relaxation. The relaxation at about 300 kHz was associated with a helix-coil transition, and that about 3 MHz was attributed to the proton transfer reaction of phenolic group. The rate constants and volume changes associated with these processes were estimated.

A experimental study of water vapor absorption characteristics using four components solution for gas fired absorption chiller (가스냉난방기용 4성분계 흡수용액의 수증기 흡수특성에 관한 실험적 연구)

  • Lee Yong-Won;Oh Young-Sam;Park Dal-Ryung;Baek Young-Soon
    • Journal of the Korean Institute of Gas
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    • v.2 no.4
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    • pp.47-52
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    • 1998
  • Water vapor absorption performance of four components solution ($LiBr+LiNO_3+LiC1+H_2O$) which could be substituted for commonly used $LiBr/H_2O$ solution in water cooled abosorption chiller is tested using a vertical tube absorber. Inlet solution concentration, inlet solution temperature, solution flow rate and inlet temperature of cooling water is varied as experimental parameters. The results of the experiment of water vapor absorption performance show that four components solution should have $2\%$ higher concentration for equal absorption capacity of $LiBr/H_2O$. But considering that four components solution have higher solubility than LiBr solution about $3\%$ high oncentration, four components solution ($LiBr+LiNO_3+LiC1+H_2O$) have more absorption capacity than LiBr solution in actual absorption chiller and can be applied to a small or air cooled absorption chiller.

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Synthesis, Reactions and Catalytic Activities of Water Soluble Rhodium and Iridium-Sulfonated Triphenylphosphine Complexes. 1. Polymerization of Terminal Alkynes

  • 주광석;김상열;진종식
    • Bulletin of the Korean Chemical Society
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    • v.18 no.12
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    • pp.1296-1301
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    • 1997
  • Polymerization of terminal alkynes (phenlacetylene and 4-ethynyltoluene) catalyzed by water soluble rhodium (Ⅰ) complex, RhCl(CO)(TPPTS)2 (TPPTS=m-P(C6H4SO3Na)3) (1) selectively produces cis-transoid polymers at room temperature in homogeneous solution of H2O and MeOH as well as in biphasic solutions of H2O and CHCl3. The rate of polymerization is higher in H2O/MeOH than in H2O/CHCl3. The iridium analog, IrCl(CO)(TPPTS)2 (2) shows catalytic activity for the polymerization of phenylacetylene only at elevated temperature to give trans-polymers. The polymerization rate increases significantly when the trimethylamine N-oxide (Me3NO) was added to the reaction mixtures. The electronic absorption spectra of the cis-transoid polymers show three absorption bands whereas the trasn-polymers show only one absorption band. It seems that the electronic absorption bands depend on the configuration of the polymers.

A Study on Remodeling for Solar driven $NH_3/H_2O$ absorption chiller (태양열 구동 $NH_3/H_2O$ 흡수식 냉동기 리모델링 연구)

  • Shin, You-Soo;Maeng, Ju-Sung;Kwak, Hee-Youl
    • Journal of the Korean Solar Energy Society
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    • v.23 no.4
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    • pp.37-43
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    • 2003
  • The aim of this research is to study the feasibility of the solar(hot fluid) driven $NH_3/H_2O$ absorption chiller, made by re-manufacturing of Gas fired $NH_3/H_2O$ absorption chiller. This experimental study is performed with the temperature of the inlet hot fluid of generator. In order to determine the inlet temperature of the generator, which gives maximum COP, the experimental data are obtained with various hot fluid supply temperature in range of $130\sim170^{\circ}C$. Remodeled chiller is operated with periodical cooling effect, which due to mixture subcooled pool boiling, then the COP is evaluated in average. The maximum COP$(\sim0.36)$ is at $160^{\circ}C$. The temperature is stable operation temperature range of typical vacuum collector. It offers a feasibility of solar driven $NH_3/H_2O$ absorption chiller.

Parametric Study on the $LiBr-H_2O$ Absorption Process on Horizontal Tubes (수평원관상의 $LiBr-H_2O$ 흡수특성에 대한 연구)

  • Min J. K.;Choi D. H.
    • Journal of computational fluids engineering
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    • v.5 no.1
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    • pp.33-42
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    • 2000
  • The LiBr-H₂O absorption process on a horizontal tube has been analyzed numerically. The flow field, which was calculated in the authors' previous study by solving the fully elliptic Navier-Stokes equations with accurate free-surface-tracking method, is used to solve the temperature and concentration distributions in the absorption film. With the assumption that the absorbent is linear, calculations have been made for various inlet temperature and flow-rate conditions. For low inlet temperature, the absorption rate is large in the upstream region but the mean temperature also increases and as a result the absorption decreases as the film flows to downstream while high-inlet-temperature case does the opposite. The difference in the absorption rate due to the inlet temperature change becomes smaller in the downstream than that in the upstream. For large flow rate, the heat transfer to the wall becomes poor due to the thick film and so does the absorption rate. The analyses have also been carried out for multiple tube arrangement and the results show that the absorption rate converges after a few tube rows.

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Parametric Study on the $LiBr-H_{2}O$ Absorption Process on Horizontal Tubes Using Wavier-Stokes Equations (Navier-Stokes 방정식을 사용한 수평원관상의 $LiBr-H_{2}O$ 흡수특성에 대한 연구)

  • Min J. K.;Choi D. H.
    • 한국전산유체공학회:학술대회논문집
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    • 1999.05a
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    • pp.213-218
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    • 1999
  • The $LiBr-H_{2}O$ absorption process on a horizontal tube has been analyzed using the numerical method which incorporates the fully elliptic Navier-Stokes equations for the momentum equations, the energy and mass-diffusion equations. On a staggered grid, the SIMPLER algorithm with the QUICK scheme is used to solve these equations along with the MAC method for the free surface tracking. With the assumption that the absorbent is linear, calculations have been made for various inlet temperature and flow-rate conditions. The detailed results of the parametric study, such as the temperature, concentration, absorption mass flux and wall heat flux distributions are presented. The self-sustained feature of the absorption process is clearly elaborated. The analyses have also been carried out for multiple tube arrangement and the results show that the absorption rate converges after a few tube rows.

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Coupled Heat and Mass Transfer in Absorption of Water Vapor into LiBr-$H_2O$ Solution Flowing over a Finned Inclined Surface (좁은 휜이 달린 경사면을 흐르는 리튬브로마이드 수용액 흡수기에서의 열 및 물질전달)

  • 조은준;서태범
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.9
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    • pp.860-867
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    • 2001
  • Absorption of water vapor into LiBr-$H_2O$ O solution flowing over a finned inclined surface is numerically investigated. The momentum, energy, and diffusion equation are numerically solved using a finite difference method. The four different shapes of the wall surfaces are considered to find the best surface for absorption assuming that the wall temperature and the surface tension are constant. The effects of the fin interval and Reynolds number are investigated. Based on the numerical results, it is known that the parabolic surface shows better absorption performance than the other surfaces, and that water vapor absorption increases gradually with decreasing the fin interval.

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Analysis of LiBr-H$_{2}$O Film Absorption on a Horizontal Tube (수평원관상의 LiBr-H$_{2}$O 액막흡수현상 해석)

  • Park, Il-Seok;Choe, Do-Hyeong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.2
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    • pp.670-679
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    • 1996
  • A numerical study for vapor absorption into LiBr-H$_{2}$O solution film flowing over horizontal circular tubes has been carried out. The momentum, energy and diffusion equations, which are parabolized by the boundary- layer approximation, are solved simultaneously for various mass-flow rates and inlet conditions. The results for the velocity, temperature and concentration fields, as well as the heat and mass flux at the free surface are presented. The effects of inlet conditions, i.e., flow rate, temperature and concentration, on the absorption process are also examined and discussed.