• 설비공학논문집
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• 제11권3호
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• pp.422-430
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• 1999

This paper concerns the study of a two-stage absorption heat pump cycle to utilize treated sewage. This two-stage cycle consists of coupling double-effect with parallel or series flow type and single effect cycle so that the first stage absorber and condenser produces hot water to evaporate refrigerant in the evaporator of the second stage. The effects of operating variables such as absorber temperature on the coefficient of performance have been studied for two-stage absorption heat pump cycle. The working fluid is lithium bromide and water solution. The efficiency of the two-stage absorption heat pump cycle has been studied and simulation results show that higher coefficient of performance could be obtained for the first stage with parallel flow type. The optimum ratio of solution distribution can be shown by considering the COP, the crystallization of solution and the generator temperature.

• Journal of Mechanical Science and Technology
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• 제18권7호
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• pp.1140-1149
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• 2004

The absorption characteristics of water vapor into a LiBr-H$_2$O solution flowing down on finned inclined surfaces are numerically investigated in order to study the absorbing performances of different surface shapes of finned tubes as an absorber element. A three-dimensional numerical model is developed. The momentum, energy, and diffusion equations are solved simultaneously using a finite difference method. In order to obtain the temperature and concentration distributions, the Runge-Kutta and the Successive over relaxation methods are used. The flat, circular, elliptic, and parabolic shapes of the tube surfaces are considered in order to find the optimal surface shapes for absorption. In addition, the effects of the fin intervals and Reynolds numbers are studied. The results show that the absorption mainly happens near the fin tip due to the temperature and concentration gradient, and the absorbing performance of the parabolic surface is better than those of the other surfaces.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2003년도 춘계 학술발표회 논문집
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• pp.351-357
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• 2003

In absorption system, the performance of the absorber is critical the overall system performance, size, and first-cost. The objective of this paper is to provide a comprehensive review of the significant effects that researchers have made to numerically analysis model the coupled heat and mass transfer process that occur during falling-film absorption and experimental researches. This study includes experimental work in the enhancement of absorption performance, the effect of the geometry of a vertical absorber, and the effect of configuration of absorption system. This paper is used to highlight key areas which need attention such as film ans vapor hydrodynamics, especially the non-periodicity, instability, and recirculatory motion of waves in the vertical absorber case.

• 한국방사선학회논문지
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• 제2권3호
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• pp.33-35
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• 2008

In the neutron capture experiment and calculation, the neutron absorption and scattering are very important. Especially these effects are conspicuous in the resonance energy region and below the thermal energy region. In the present study, we obtained energy dependent neutron absorption ratios of natural rhodium in energy region from 0.003 to 100 eV by MCNP-4B Code. The coefficients for neutron absorption was calculated for several types of thickness. In the lower energy region, neutron absorption is larger than higher region, because of large capture cross section (1/v). Furthermore it seems very different neutron absorption in the large resonance energy region. These results are very useful to decide the thickness of sample and shielding materials.

• 소음진동
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• 제7권5호
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• pp.797-801
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• 1997

This paper raises issues in testing the absorption coefficients of sound-absorptive samples using the standing wave apparatus according to the Korean standard of KS F 2814. The standard code does not consider any effect of air-damping which is significant in testing relatively low sound-absorptive samples. This limitation has been shown to yield much variation of sound absorption coefficients for recent samples tests whose coefficients are less than 10%. An improved method of calculating the sound absorption coefficients is proposed in this work and its effectiveness in real test is also illustrated. Finally, the guideline for the modification of our national standard code KS F 2814 is proposed.

• 한국의류학회지
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• 제18권5호
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• pp.622-627
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• 1994

The purpose of this study is to investigate the adsorption rate, adsorption quantities and the UV-Cut effects of cotton fabrics treated with several UV absorbents. The result of this study were as follows: cotton fabric treated with 2,2'-dihydroxy-4- methoxy-benzophenone shows more efficient than ones treated with 4-aminobenzoic acid and 2·hydroxy-1, 4-naphthoquinone in UV absorption. This may be due to the absorption of UV light by formation of intra moleculaar hydrogen bond. The formation of hydrogen bonds between hydrogen atoms of two hydroxy groups and one oxygen atom of carboxyl group in 2, 2'-dihydroxy-4-methoxy-benzophenone would be easier than that of the other absorbents. The adsorption isotherms of 4-aminobenzoic acid and 2-hydroxy-1, 4-naphthoquinone were similar to Freundlich type, while that of 2, 2'-Dihydroxy-4-methoxy-benzophenone was Henry type. Cotton fabrics treated with Antifade MC-100 and W Cut I-2 were just alike in UV absorption, but Antifade 8001 was inferior to the others.

• Advances in aircraft and spacecraft science
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• 제2권4호
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• pp.391-401
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• 2015

Crashworthiness design and certification have been and will continue to be the main concern in aviation safety. The effects of roll angles on fuselage section crashworthiness for typical civil transport category aircrafts were investigated. A fuselage section with waved-plates under cargo floor is suggested, and the finite element model of fuselage section is developed to simulate drop test subjected to 7 m/s impact velocity under conditions of 0-deg, 5-deg, 10-deg and 15-deg roll angles, respectively. A comparative analysis of failure modes, acceleration responses, and energy absorption of fuselage section under various conditions are given. The results show that the change of roll angles will significantly affect fuselage deformation, seat peak overloads, and energy absorption. The crashworthiness capability of aircraft can be effectively improved by choosing appropriate landing way.

• Journal of Pharmaceutical Investigation
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• 제12권2호
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• pp.45-53
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• 1982

The effects of mixture of tween 20 and span 20 or span 80 on griseofulvin absorption in rabbit were studied. The plasma concentration of griseofulvin in blood samples was determined by high pressure liquid chromatographic procedure. Griseofulvin suspension with 0.05% surfactant increased mostly drug absorption and produced about two times higher plasma level of griseofulvin than that of the suspension with 1% and 0.1% surfactant. Surfactants with H.L.B. value 4.3 resulted $2.74{\mu}g/ml$ of maximum plasma levels of griseofulvin at 18 hours after its oral administration and surfactants with H.L.B. value 16.7 resulted $0.56{\mu}g/ml$ of peak plasma levels of griseofulvin at 1 hour after its oral administration.

• Journal of electromagnetic engineering and science
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• 제15권3호
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• pp.167-172
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• 2015

Research results on possible effects caused by radiofrequency fields in children are limited because most of the studies published so far have focused on adults, rather than children. Mobile phone use is now widespread, even among younger children. If a biological risk due to mobile phone exposure is found, it might be greater in children because their bodies might be more sensitive to radiofrequency energy. The issue of a possible difference in sensitivity between adults and children begins with whether any difference exists physically in terms of electromagnetic absorption. This paper presents a review of recent publications on dosimetric comparisons between children and adults with respect to radiation from mobile phones. The issue of the health effects of mobile phone use is beyond the scope of the present review. Most of the dosimetry research on possible differences in power absorption between children and adults has been based on numerical modeling and analysis. The understanding of the results so far is presented and needed studies are described.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.885-891
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• 2003

Effects of each acoustic property on absorption characteristics of polyester fiber materials has been studied in this paper. It would be impossible for us to measure effects of each acoustic property by experimental method since we cannot make sound-absorbing materials in which only one of the properties is changed. We have adopted a numerical prediction method to carry out parameter studies for each acoustic property. And to get a general behavior of acoustic performance of the materials, the numerical simulation has been repeated to several cases of different bulk density. Finally we have obtained frequency-dependent control factors in the absorption performance which gives us design capability of acoustic absorbing materials.