• 설비공학논문집
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• 제16권10호
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• pp.990-998
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• 2004

Dynamic behavior of an ammonia-water absorption system was investigated numerically. Thermal-hydraulic model for a single-effect 3 RT chiller was developed by applying transient conservation equations of total mass, $NH_3$ mass, energy and momentum to each component. Transient variations of system properties and transport variables were analysed during start-up operation. Numerical analyses were performed to quantify the effects of bulk concentration and charging ratio on the system performance in terms of cooling capacity, coefficient of performance, and time constant of system. For an absorption chiller considered in the present study, optimum charging ratio and bulk concentration were to found to exist, which resulted in the maximum cooling capacity and COP. The time constant increased as the charging ratio increased, but decreased with the increase of bulk concentration.

• 한국수소및신에너지학회논문집
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• 제29권5호
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• pp.530-537
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• 2018

The effect of temperature and absorption capacity on heat of reaction, which is one of the characteristic studies of $CO_2$ absorption, were investigated in a differential reaction calorimeter (DRC) by using piperazine (PZ) and 2-methylpiperazine (2-MPZ). For all absorbents, $CO_2$ loading capacity decreased with increasing the temperature, while the heat of reaction increased, it figured out that these had a linear correlation between $CO_2$ loading capacity and/or heat of reaction and the temperature. The heat of reaction of all absorbents increased with increasing $CO_2$ loading capacity, especially 2-MPZ rapidly increased at $70^{\circ}C$. The reason for increase in the heat of reaction was occurred the regeneration of $CO_2$, which is a reverse-reaction, simultaneously with the absorption.

• 한국수소및신에너지학회논문집
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• 제24권4호
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• pp.334-339
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• 2013

In this study, as a candidate of the carbon dioxide ($CO_2$) absorbents, the mixture solution of polyethylene glycol dimethyl ether (PEGDME) and tetrahydrofuran (THF) were investigated. $CO_2$ absorption rate was measured by using high pressure $CO_2$ screening equipment in the range of 1 - 10wt% THF. Absorption capacity of the mixture solution was also estimated. Based on the results, we found that mixture solution containing THF had higher absorption rate and $CO_2$ loading capacity compared to PEGDME at $25^{\circ}C$.

• 한국환경과학회지
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• 제19권1호
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• pp.97-103
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• 2010

The biodegradable oil absorption resin was prepared by the suspension polymerization of the modified starch and 2-ethylhexyl acrylate (2-EHA). The highest oil-absorption capacity of B-PEHA prepared showed at the condition of the modified starch content of 10 g and ethyleneglycol dimethacrylate (EGDMA) of 0.133 wt%. Its maximum oil absorption capacity per g of oil absorber was chloroform 30.88 g, toluene 19.75 g, xylene 18.78 g, tetrahydofuran (THF) 15.96 g, octane 11.43 g, hexane 9.5 g diesel oil 12.80 g, and kerosene 13.79 g, respectively. The biodegradation of poly-2-ethylhexylacrylate (B-PEHA) determined by enzymatic hydrolysis showed approximately 17~20%. The results showed that the preparation of the biodegradable oil absorption resin is available using the modified starch.

• Advances in materials Research
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• 제11권3호
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• pp.237-250
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• 2022

The cone bolts with expanded front ends supply improved anchoring performances and increase energy absorbing capacities due to ploughing in the grouted drills. Within this study, use of a novel energy absorber for the cone bolt heads were investigated to assess its design in terms of supplying high support performances. Additionally, different grout material designs were tested to investigate whether the energy absorption capacities of the rock bolts can be improved using a silicone based thermoset polymer (STP) additive. To determine load bearing and energy absorption capacities, a series of deformation controlled pull-out tests were carried out by using bolt samples grouted in rock blocks. According to the results obtained from this study, maximum load bearing capacities of cone bolts are similar and mostly depend on the steel material strength, whereas the energy absorption capacity was determined to significantly vary in accordance with the displacement limits of the shanks. As a result of using STP additive and new polyamide absorber rings, displacement limits without the steel failure increase. The STP additive was found to improve the energy absorption capacities of grouted cone bolts. The absorber rings designed within this study were also assessed to be highly effective and able to double up the energy absorption capacities of the cone bolts.

• 공업화학
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• 제21권3호
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• pp.284-290
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• 2010

본 연구에서는 이산화탄소 포집 기술에 적용할 수 있는 흡수제인 $K_2CO_3$와 homopiperazine (homoPZ)을 이용한 혼합 수용액을 사용하여 이산화탄소 흡수 특성을 연구하였다. 기액 흡수평형(VLE) 장치를 사용하여 60, $80^{\circ}C$에서 이산화탄소 평형분압($P_{CO_2}^*$)과 압력변화를 측정하였고, 40, 60, $80^{\circ}C$에서 반회분식(semi-batch) 흡수 장치를 사용하여 흡수능을 평가하였다. $K_2CO_3$ 수용액의 결정 생성 문제 개선과 $CO_2$ 흡수량 및 흡수속도 증대를 위해 고리형 diamine인 homoPZ를 증진제로 사용하였으며, 기존 연구된 MEA, $K_2CO_3$와 $K_2CO_3$/piperazine (PZ)과의 성능을 비교 평가하였다. 실험결과 homoPZ를 첨가하였을 경우 $K_2CO_3$ 수용액보다 이산화탄소 평형분압이 낮아져 흡수능이 개선되었으며, 흡수속도는 $60^{\circ}C$에서 약 0.375배, $80^{\circ}C$에서 약 0.343배 향상되었다. $K_2CO_3$/homoPZ 수용액의 $CO_2$ loading capacity는 $60^{\circ}C$에서 $K_2CO_3$/PZ 수용액과 유사하였고, MEA 수용액보다는 우수하였다.

• 대한기계학회논문집
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• 제19권1호
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• pp.277-283
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• 1995

For the development of low NO$_{x}$ gas burners aimed for absorption chiller/heater unit, three proto type burners of different capacity (265000, 498000, and 664000 kcal/h) have been manufactured through a combustion method of step-by-step air injection. In order to characterize the overall features of the flame and the properties of the emission gas, the temperature of the flame and the concentration of NO$_{x}$ and CO were determined. The main factors in the design of burners (the area of primary air injection, the diameter of secondary air injection hole, fuel nozzle diameter) were observed to increase linearly with the scale-up of burner capacity. The flame temperature profiles of the burners were observed to be almost similar, irrespective of their capacity. However, as their capacity increased, the flame temperature slightly increased and the hot region of the flames moved to ward the flame tip along with the expansion to the direction of radius. From the proto type units, the amount of their NO$_{x}$ emission was determined to be around 25 - 30 vppm(3% )$_{2}$) and the CO emission was less than 19 vppm (3% $O_{2}$).TEX>).

• 한국지진공학회논문집
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• 제5권5호
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• pp.47-56
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• 2001

원전 격납건물은 내진 안정성을 확보하기 위해 설계단계에서 여유나 보수성을 부여하게 된다. 원전 구조물의 내진성능 평가는 이러한 여유나 보수성을 배제한 실질적인 성능 및 응답을 기준으로 평가하게 된다. 본 연구에서는 내진성능 평가에 고려되는 구조물의 성능 및 응답관련 계수들 중 그 기여도가 비교적 큰 비탄성 에너지 흡수계수의 산정방법에 대한 비교를 수행하였다. 또한 각종 방법에 따라 산정된 비탄성 에너지 흡수계수에 따른 HCLPF(high confidence of low probability of failure)값의 변화를 분석하였다. 연구결과 원전 격납건물의 비탄성 에너지 흡수계수는 1.5~1.75로 나타났다. 구조물의 내진성능을 명확히 평가하기 위해서는 먼저 구조물의 비선형 거동 및 연성도를 정확히 평가하여야 함을 알 수 있다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.581-586
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• 2002

Addition of steel fiber to shotcrete is to improve the brittleness of concrete. Quality of steel fiber reinforced shotcrete can be evaluated by quantitive analysis of toughness characteristics after cracking. The toughness characteristics can be expressed by absolute value of energy absorption capacity, non-dimensional toughness index related to the energy absorption capacity, and equivalent flexural strength at arbitrary deflection. In this study, merits and demerits of flexural toughness by RTA round panel of Australia and other specifications have been analyzed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.830-839
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• 2008

This study is designed to manufacture the upgraded sound absorption concrete by using foamed concrete by using artificial light weight aggregate which raises the continuous void ratio to increase the sound absorption ratio and improve the strength. In manufacturing the sound absorption block, the pre-foaming form is applied to generate continuous voids, controlling the density by the addition of bubbles. It is general that the more porosity creates, the weaker strength becomes. Each of specimens are used for this experiment and measured their absorption ratio to examine the absorption property depending on frequency. As a results of experiment, it is evaluated that the absorption capacity of the sound absorption block has relation to compression strength and surface shape.