• Title/Summary/Keyword: Absorption effect

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Development of High Efficiency Cycle by Combining Double-Effect with Single-Effect Absorption Chiller Systems (이중 효용과 일중 효용을 복합한 다단 재생 고효율 흡수식 냉동 사이클 개발)

  • Yun, Sang Kook
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.7
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    • pp.360-365
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    • 2017
  • Recently, development efforts of triple-effect absorption chiller have been increased in order to improve the efficiency of double-effect absorption chiller. However, triple-effect absorption chiller has some disadvantages, including high corrosion characteristic of LiBr solution at high temperature of $200^{\circ}C$. Moreover, it is necessary to develop new components for operation under high pressure of 2 bars even though COP is increased to 1.6 or 1.7. The objective of this study was to introduce a new system by combining double effect absorption chiller with single effect absorption chiller with multi-generators using bypass flow of LiBr dilute solution to $3^{rd}$ generator to overcome the disadvantages of triple-effect chiller and improve energy efficiency. Results indicate that the new absorption cycle had a much higher efficiency than double-effect chiller system, showing significant improvement when bypass solution flow rate of 25% was applied to the $3^{rd}$ generator using the main dilute solution of the absorber. The COP of the new chiller system was found to be 1.438, which was 21.7% higher than that (1.18) of the present double-effect system. The COP was decreased when solution by-pass rate to the $3^{rd}$ generator was increased. In addition, lower cooling water temperature caused higher COP. Therefore, the multi-generator system with by-pass solution might be an excellent chiller alternative to triple-effect absorption chiller with higher efficiency.

Comparative study of rifampicin pharmacokinetics administered orally and intravenously in the fasted and non-fasted rats

  • Shim, Chang-Koo;Lee, Jeong-Uk
    • Archives of Pharmacal Research
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    • v.8 no.3
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    • pp.177-186
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    • 1985
  • Effect of food on the absorption characteristics of oral rifampicin was studied in the fasted rats. Rifampicin dissolved in a new cosolvent was also injected to the rats intravenously, and the pharmacokinetic analysis was performed to explain the effect of food on the gastrointestinal absorption of rifampicin. Rifampicin was absorbed rapidly and completely in the fasting state. Food had a profound effect on the gastrointestinal absorption of rifampicin, i. e., bioavailability and the extent of absorption were decreased to less than one-third of the fasting state in the postprandial state. Food seemed to imhibit the absorption and reabsorption of rifampicin in the gastrointestinal tract, but not the absorption rate constant. Hepatobiliary excretion seemed to be the major route of elimination, since the renal clearance accounted for only 8 % of the systemic clearance. Nevertheless, first-pass effect was negligibly small and most of rifampicin absorbed could reach systemic circulation. Serum concentration change of oral rifampicin on multiple dosing differed markedly in the fasting and postprandial state, which suggested the need of careful adjustment of dosage regimen in both states.

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Effect of Ginseng on the Intestinal Absorption of Ethanol (인삼 성분이 Ethanol의 장관내 흡수에 미치는 영향)

  • Huh, Keun;Choi, Chong-Won
    • YAKHAK HOEJI
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    • v.27 no.2
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    • pp.163-168
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    • 1983
  • The effect of ginseng butanol fraction (total sponin) on the absorption rate of ethanol in rat intestine was examined. Ginseng butanol fraction showed inhibitory effect on the intestinal absorption of ethanol in situ as well as in vitro test. Ginseng butanol fraction markedly decreased the ethanol blood level, delayed onset time of ethanol effect and shortened sleeping time when it was adminstered orally together with ethanol. These results suggest that ginseng may alter the ethanol blood level by decreasing the intestinal absorption of ethanol.

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Recent Advances in Intranasal Drug Delivery (경비 약물전달체계의 최근의 진보)

  • Park, Gee-Bae;Lee, Yong-Suk;Lee, Kwang-Pyo
    • Journal of Pharmaceutical Investigation
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    • v.22 no.2
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    • pp.77-96
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    • 1992
  • In recent years intranasal administration of drugs has received great attention as a convenient and efficent method of drug delivery because of its potential to improve the systemic effect of substances with a poor oral bioavailability. In addition to offering advantages such as rapid absorption, fast onset of action and avoiding the first -pass effect, it provides for delivery of drugs from very lipophilic drugs such as steroids to polar and hydrophilic drugs such as peptides and proteins. However, little is still known about the nature of various barriers existing in the nasal mucosae as well as mechanism by which these molecules are absorbed. This review article therefore intends to discuss nasal physiology, experimental methods and evaluation of absorption from the nasal cavity, factors influencing nasal absorption, mechanism of nasal absorption, approaches to improve the residence time and to obtain the sustained-release effect of intranasally administered drugs, promoters and mechanism for the enhancement of nasal absorption, Several examples for intranasal delivery of various systemically effective drugs will be reviewed and illustrated. Drug metabolism in the nasal mucosae and problems associated with intranasal administration of drugs will be also discussed.

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A Study on the Absorption-Enhancing Effect of Sodium-5-methoxysalicylate (Sodium-5-Methoxy Salicylate의 흡수촉진 효과에 관한 연구)

  • 김기헌
    • YAKHAK HOEJI
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    • v.29 no.3
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    • pp.111-116
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    • 1985
  • Effect of sodium-5-methoxysalicyclate (5MSA-Na) on the absorption of cefmetazol (CMZ) was studied in rectum and duodenum of rats via in situ loop method. Effect of 5MSA-Na on the absorption of CMZ showed markedly different results in rectum and duodenu. Penetration of 5MSA-Na was greater in rectum than in duodenum and water-transfer was markedly increased in duodenum.

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A Study on the Sound Absorption Coefficient by Varying Sample Size (시편의 크기에 따른 흡음계수 변화 연구)

  • 정성수;이우섭;조문재;서상준
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.5
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    • pp.83-88
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    • 2001
  • The sound absorption coefficient of glass wool (bulk density of 48 kg/m:1 and 32 kg/m7) was measured by reverberation room method as varying their cross-sectional area. The results show that the absorption is larger for smaller samples because of edge effect. The absorption coefficient with two different kinds of sources. 1/.7-octave band and while noise, gives similar values.

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Effects of Egg Phospholipids on the Intestinal Absorption of Lipids

  • Noh Sang K.;Koo Sung I.
    • Proceedings of the Korean Society of Food Science and Nutrition Conference
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    • 2004.11a
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    • pp.47-52
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    • 2004
  • This study was conducted to determine the effects of egg phospholipids [(Phosphatidylcholine (PC) and sphingomyelin (SM)] on intestinal absorption of cholesterol and other lipids. Each rat with Iymph cannula was infused via a duodenal catheter at 3.0 mL/h for 8 h with a lipid emulsion containing triolein, cholesterol and PC in 24 mL PBS. The PC in the lipid emulsion was egg PC (EPC), hydrogenated egg PC (HPC), or soy PC (SPC). The EPC in the lipid emulsion markedly lowered the Iymphatic absorption of cholesterol, compared with SPC and a lipid emulsion containing no PC. The HPC further lowered the absorption of cholesterol. The phospholipid output was not affected by the source of PC infused. The total Iymphatic output of oleic acid (18: 1), the major fatty acid infused in the form of triolein, did not differ among the NPC, SPC and EPC groups, but was significantly lower in the HPC group. The findings provide the first evidence that EPC markedly lowers the Iymphatic absorption of cholesterol under in vivo conditions. The inhibitory effect of EPC appears to be due to the higher degree of saturation of its acyl groups relative to SPC, suggesting that the intestinal absorption of egg cholesterol may be reduced by the presence of PC in e99 yolk. Experiment 2 was designed to determine whether egg SM, structurally similar to PC, also inhibits the Iymphatic absorption of cholesterol. Egg SM lowered the Lymphatic absorption of cholesterol in a dose dependent manner. Likewise, SM lowered the Iymphatic absorption of oleic acid, whereas it had no effect on retinol absorption. SM at a high dose lowered the Iymphatic outputs of both PC and SM, whereas there was no such effect at a lower dose. These results also indicate that luminal egg SM has an inhibitory effect on the intestinal absorption of cholesterol and other lipids of relatively high hydrophobicity.

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Development of Vibration Absorption Device for the Transportation-Trailer System (IV) - Connecting Hitch, Leaf Spring and Shock Absorber Suspension - (수송 트레일러의 충격흡수장치 개발 (IV) - 동력경운기 적재함의 연결히치, 판스프링, 쇽업쇼바 -)

  • Hong, Jong Ho;Wu, Yong Gen
    • Journal of Biosystems Engineering
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    • v.37 no.6
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    • pp.359-364
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    • 2012
  • Purpose: This study was conducted to analyze the vibration absorption effect for the agricultural product transportation-trailer equipped with vibration absorbable connecting hitch, leaf spring suspension, and shock absorber simultaneously (HLS), comparing with the trailer equipped with vibration absorbable connecting hitch only(H), trailer equipped with connecting hitch and leaf spring suspension (HL), and existing trailer with no vibration absorption device (E). Methods: Vertical accelerations were measured at driver seat and front, middle, rear parts of trailer bottom with no load for 4 types of transportation-trailer, and analyzed using FFT analyzer. Results: The magnitude of average vibration accelerations occurred up to 20 Hz, at this low frequencies the severe damage for agricultural products could be represented, was lower (maximum 6 times) for HLS trailer compared with H trailer. And vibration absorption effect for HLS trailer was also higher up to 40-80 Hz and 80-100 Hz, but the difference was less. At driver seat, the vibration absorption effect was high severely for HL and HLS trailer, and the magnitude of vibration acceleration was showed less difference in comparing at trailer bottom. Conclusions: From the test results, it could be recommended that the agricultural products transportation trailer should be equipped with vibration absorption device of HLS.

Effect of Geometrical Shape and Cold Work on Deformation of the Hydrogen Absorption Metal with Hydrogen Absorption-Desorption Cycling (수소저장-방출싸이클링에 의한 수소저장금속의 변형거동에 관한 형상 및 가공의 영향)

  • Jeong, Y.G.
    • Journal of Hydrogen and New Energy
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    • v.14 no.3
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    • pp.207-216
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    • 2003
  • By using the electrochemical method, the relation between the deformation and the geometrical shape, and the effect of cold work on hydrogen absorption-desorption cycling in palladium were investigated, In order to study this problem, four kinds of the Pd specimens used were plates and bars as cold worked and annealed states. As results, it is found that the deformation of thickness direction in the palladium plates increased whereas other lateral directions decreased. But the palladium bars showed the same deformation ratio in all directions because of uniform distribution of the $\beta$ phase. Grains in the plate specimens were greatly deformed after hydrogenation cycling whereas grains in the bar specimens were pulverized. Also, deterioration of the hydrogen absorption rate of the bar specimen was larger than the plate specimen. And the effect of cold work on hydrogen absorption capacity was relatively small.

Catalytic effect of metal oxides on CO2 absorption in an aqueous potassium salt of lysine

  • Dharmalingam, Sivanesan;Park, Ki Tae;Lee, Ju-Yeol;Park, Il-Gun;Jeong, Soon Kwan
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.335-341
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    • 2018
  • We report the catalytic effects of metal oxides on the $CO_2$ absorption rate in an aqueous potassium salt of ${\text\tiny{L}}-lysine-HCl$ using the vapor liquid equilibrium method. The best $CO_2$ absorption rate obtained through testing metal oxides in a highly concentrated potassium salt of amino acids (2.0 M) was identified using CuO. The recyclability of the metal oxides was tested over three cycles. The catalyst CuO was found to enhance the absorption rate of $CO_2$ by 61%. A possible mechanism was proposed based on NMR spectroscopy studies. Further, the effect of change in liquid absorbent viscosity on $CO_2$ absorption is discussed.