Search

To investigate the optimal detector material for prompt gamma imaging during boron neutron capture therapy, in this study, we evaluated the characteristic regarding radiation reaction of available detector materials using a Monte Carlo simulation. Sixteen detector materials used for radiation detection were investigated to assess their advantages and drawbacks. The estimations used previous experimental data to build the simulation codes. The energy resolution and detection efficiency of each material was investigated, and prompt gamma images during BNCT simulation were acquired using only the detectors that showed good performance in our preliminary data. From the simulation, we could evaluate the majority of detector materials in BNCT and also could acquire a prompt gamma image using the six high ranked-detector materials and lutetium yttrium oxyorthosilicate. We provide a strategy to select an optimal detector material for the prompt gamma imaging during BNCT with three conclusions. Keywords: Boron neutron capture therapy (BNCT), Prompt gamma, Detector materials, Monte Carlo simulation

Enhanced mass transport in polymer electrolyte membrane fuel cells (PEMFCs) is required for achieving high performance because concentration losses dominate cell performance. In particular, the flow field is crucial for mass transport. Recently, metal foam has been proposed as an alternative flow field owing to its three-dimensional pores, high porosity, and enhanced electrical conductivity. Here, we inspect the microstructure of various copper foams and investigate its effect as a flow field on PEMFCs. The PEMFCs with the optimized foam flow field deliver the highest performance reported to date. A large contact area and small ribs of the optimized foam flow field are advantageous for mass transfer and ohmic resistance. In addition, the internally generated pressure increases the partial pressure of the reactant, which leads to increased performance. This foam flow field has a significant potential for achieving high cell performance by enhancing the electrochemical reaction of the catalyst.

In this study, an iridium oxide (IrO2) inverse-opal membrane-electrode assembly (inverse-opal MEA) was fabricated via the decal-transfer method for an anode in polymer-electrolyte membrane water electrolysis (PEMWE) to decrease the loading of the noble catalyst. Electrodeposition parameters including current and total number of cycles were investigated to achieve the IrO2 inverse-opal electrode. The inverse-opal MEA with ultra-low loading exhibited outstanding performance that exceeded or was comparable to that obtained in other PEMWE studies. Additionally, it exhibited higher performance and lower ohmic and charge-transfer resistance when compared with that of commercial IrO2. Furthermore, the performance corresponded to the highest mass activity reported to date since the loading in the inverse-opal MEA was ultra-low. This was because the inverse-opal structure improved electron transfer owing to the interconnected pores and increased the surface area due to high porosity, thereby leading to the enhanced utilization of the catalyst.

Global warming due to greenhouse gases is an issue of great concern today. Fossil fuel power plants, especially coal-fired thermal power plants, are a major source of carbon dioxide emission. In this work, carbon capture and utilization using sodium hydroxide was studied experimentally. Application for flue gas of a coal-fired power plant is considered. Carbon dioxide, reacting with an aqueous solution of sodium hydroxide, could be converted to sodium bicarbonate (NaHCO3). A bench-scale unit of a reactor system was designed for this experiment. The capture scale of the reactor system was 2 kg of carbon dioxide per day. The detailed operational condition could be determined. The purity of produced sodium bicarbonate was above 97% and the absorption rate of CO2 was above 95% through the experiment using this reactor system. The results obtained in this experiment contain useful information for the construction and operation of a commercial-scale plant. Through this experiment, the possibility of carbon capture for coal power plants using sodium hydroxide could be confirmed.

The absorption efficiency of amine CO2 absorbent (KoSol-5) developed by KEPCO research institute was evaluated using a 0.1 MW test bed. The performance of post-combustion technology to capture two tons of CO2 per day from a slipstream of the flue gas from a 500 MW coal-fired power station was first confirmed in Korea. Also the analysis of the absorbent regeneration energy was conducted to suggest the reliable data for the KoSol-5 absorbent performance. And we tested energy reduction effects by improving the absorption tower inter-cooling system. Overall results showed that the CO2 removal rate met the technical guideline (CO2 removal rate : 90%) suggested by IEA-GHG. Also the regeneration energy of the KoSol-5 showed about 3.05 GJ/tonCO2 which was about 25% reduction in the regeneration energy compared to that of using the com- mercial absorbent MEA (Monoethanolamine). Based on current experiments, the KoSol-5 absorbent showed high efficiency for CO2 capture. It is expected that the application of KoSol-5 to commercial scale CO2 capture plants could dramatically reduce CO2 capture costs.

이 연구는 관상동맥 CT 석회화점수 검사를 2회 이상 받은 자 중에서, 이전에 비하여 점수가 낮아진 원인을 후향적으로 분석하였다. 건강검자 환자 100명(남자 85명 60.6±6.9세, 여자 15명 67.2±7.3세)을 대상으로 하였다. 석회화점수 감소가 발생한 경우를 Agatston의 분류 방법에 따라 minimal (1-10), mild(11-100), moderate(101-400), severe (400< ) 4개 그룹으로 분류하였다. Mild 그룹에서 49명으로 가장 많았으며, minimal 그룹에서 감소율 변동이 가장 크게 나타났다. 석회화점수 감소 요인은 Scan location 불일치 51%, Motion artifact26%, 장비변동 14%, 작업자의 실수 5%, 입력 miss 2%, Image loss 1%, 부정맥 1% 로 나타났다. Scan location의 불일치는 scan된 석회화의 slice 위치에 따른 부분체적 효과로 생각되며, 관상동맥 석회화 점수가 작은 100 이하 그룹에서는 높은 변화폭(19.7%)이 나타났고 100 이상의 그룹에서는 낮은 변화폭(2.2%)을 보여 석회화 점수에 따라 허용될 수 있는 변화폭이 달라진다는 것을 알 수 있었다. Motion artifact 요인은 26%로 나타났으며, 이는 높은 심박동에 의한 것으로 심박동이 높거나 검사 전 폐기능, 운동부하 등 심박동에 영향을 미치는 선행검사와 밀접한 관련이 있었다.

본 연구에서는 다양한 CO2 재활용 기술 중 경제성 및 CO2 감축량 효과가 큰 것으로 평가되는 CO2 활용 중탄산나 트륨 제조기술 대상으로 상용 플랜트 운영시 전체 CO2 감축량을 산정하고자 하였다. 상기 CO2 재활용 기술은 발전소 배가스 중에 포함된 CO2의 탄산화 반응을 통해 상업적으로 유용한 중탄산나트륨을 제조하는 기술로서 현재 한국동서 발전의 지원을 받아 한전 전력연구원에서 연구개발 진행 중이다(기술개발 사업명: NCCU, Non-Capture CO2 Utilization). 본 기술의 CO2 감축량 산정을 위해 하루 100톤 CO2 처리 규모(연간 36,500톤 CO2 처리 가능, 발전 용량 기준 5 MW 급)의 상용급 플랜트를 대상으로 공정모사 프로그램(PRO/II 9.1)을 활용한 열 및 물질 수지 분석을 수행하였으며 특히 종래 유사기술과의 비교를 통한 간접 CO2 감축량 산정을 위해 탄산나트륨 및 중탄산나트륨 등의 제조를 위한 대표적기술인 Solvay 공정과의 에너지 사용량을 비교·분석하였다. 분석 결과 종래 Solvay 공정은 단위 중탄산나트륨 생산을 위한 에너지 사용량이 약 7.4 GJ/tNaHCO3으로 이를 해당 에너지를 얻기 위해 필요한 석탄 사용량 및 CO2 발생량으로 환산시 연간 약 48,862 톤 CO2에 해당 된다. 반면 발전소 배가스 중에 포함된 CO2를 활용한 중탄산나트륨 제조공정의 경우 탄산화 반응에 의한 CO2 직접 포집분(연간 약 36,500 톤)과 동일 화합물 생산을 위한 종래 공정(Solvay) 대비 낮은 에너지 사용량에 따른 간접적인 CO2 저감량(연간 약 46,885 톤) 효과로 전체 CO2 감축량은 약 83,385톤으로 산정되었다. 상기 분석을 통해 본 논문의 CO2 활용 중탄산나트륨 제조기술은 제품 판매에 따른 경제적 효과뿐만 아니라 종래 공정에 비해 낮은 에너지 사용으로 CO2 저감효과가 매우 높아 대규모 CO2 저장 공간이 필요한 CCS(Carbon Capture & Sequestration) 기술의 대안기술로서 유망한 것으로 분석되었다.

A performance and economic analysis of a commercial-scale coal-fired power plant with a post-combus- tion CO2 capture process in South Korea was performed. Based on the KoSol Process for CO2 Capture (KPCC) devel- oped by the Korea Electric Power Company Research Institute, a power plant cost model coupled with a performance model was developed to evaluate the levelized cost of electricity and the cost of CO2 avoided for power plants with CCS. A techno-economic evaluation result, based on the general guideline suggested by the IEA task force group and key performance data of the pilot-scale CO2 capture test results showed that at the base case, the LCOE of a commer- cial-scale USC power plant with CCS in South Korea will increase from 47 USD/tCO2 (without CCS) to 68 USD/tCO2 (with CCS), and the cost of CO2 avoided was calculated as 33 USD/tCO2. Comparing this with various studies in other literature showed that the cost of CO2 avoided for power plants in South Korea was much lower than that of the OECD average, which was mainly due to the relatively low capital expenditure (CAPEX) and operating expenditure (OPEX) of a power plant with/without CCS.

Capture and storage of post combustion CO 2 from fossil fuel power plants is the best technique that can be rapidly and safely employed for the control of greenhouse gas emissions. Test bed studies with highly efficient amine CO 2 solvent (KoSol −4 ) developed by KEPCO Research Institute was performed. For the first time in Korea, evaluation of post-combustion CO 2 capture technology to capture 2 t-CO 2 /day from a slipstream of flue gas from a commercial scale coal-fired power station was performed. Based on a chemical absorption/regeneration process with KoSol −4 , we have studied the effects of lean solvent flow rate, input location and inter-cooling of absorbent, pressure and temperature of stripper for process optimization. This optimization aimed to reduce the energy for solvent regeneration. The optimum point in flow rate of lean absorbents was 700 kg/h in 350 Sm 3 /h flue gas. And the regeneration energy using new solvent was 3.02 GJ/t-CO 2 in 90% CO 2 removal, flue gas temperature of 40 °C and stripper pressure of 0.35 kgf/cm 2 . In addition, corrosion rate of the pilot plant were measured in six points. It is the largest as 40.52 mpy in the bottom of the stripper tower.

급성기 허혈성 뇌졸중 증상이 있는 뇌 관류 CT 검사를 시행한 환자를 대상으로 장비사가 제시한 고정 시간 기법(Fixed time technique)과 조영제 추적 기법(Bolus tracking technique)을 비교하여 환자의 피폭선량을 분석하고자 하였으며, 조영제 추적 기법의 유용성과 최적의 조영증강 구간을 구현하는 Time graph를 알아보기 위한 것이다. 환자에서는 PCT의 $CTDI_{VOL}$ 은 고정시간기법에서 431.72mGy, Bolus tracking에서 323.61mGy로 측정되었고, DLP값은 고정시간기법에서 $1243.47mG y{\cdot}cm$ , Bolus tracking에서 $932mGy{\cdot}cm$ 로 측정되었다. Time graph는 고정시간기법에서 다양하게 나타났으나, Bolus tracking 기법에서는 최적의 Time graph를 얻을 수 있었으며, 뇌 관류 CT검사 시 Bolus tracking기법을 적용하여 피폭선량을 25% 정도 감소시킬 수 있었다. 【This study was conducted to analyze the patient's exposed dose targeting the patients who had acute ischemic stroke symptoms and CT brain perfusion scan, by comparing fixed time technique and bolus tracking technique which was provided by the manufacturer and to identify the Time graph to implement the usability of contrast medium's tracking technique the best contrast enhancement intervals. $CTDI_{VOL}$ of PCT in patient appeared to be 431.72mGy in fixed scan delay protocol, whereas 323.61mGy in Bolus tracking technique. The value of DLP appeared to be $1243.47mGy{\cdot}cm$ in fixed scan delay protocol, whereas $932mGy{\cdot}cm$ in Bolus tracking technique. Time graph appeared to be various in fixed scan delay protocol, whereas the optimal time graph could be obtained in Bolus tracking. The exposure dose could be reduced by 25% applying Bolus tracking technique when taking brain perfusion CT scan.】

To study the positioning error according to the use of belly board and body mass index (BMI) for rectal cancer radiotherapy, a retrospective study was conducted on 114 patients from January 2012 to March 2013. The median age of the patients was 58 (29-83 years), mean BMI was (), 31 patients used belly board and 83 did not use belly board. There were a total of 527 AP & LAT images of treatment (EPID), and the mean and standard deviation of each X, Y, Z axis were , , and , respectively. Based on the BMI of 24 or higher, error occurrence risk of higher or equal to 2mm on Z axis was 4.8 times higher compared to BMI of 24 or lower (p

The objectives of this study were to investigate the degrees of emotional labor, the effects to organizational effectiveness and the significant factors influencing organizational effectiveness in radiation therapy professional. The subjects of this study were the radiation therapists working at the hospital in Seoul and Gyungi. The self-reported questionnaires were administered to 205 radiation therapists and the data were analyzed with SPSS 19.0 package. The level of emotional labor of single or female subjects were revealed higher than married or male. The professionalism of job has significant correlation with emotional labor. Significant explanatory variables of the degrees of emotional labor included organization culture, distress and self-leadership. These three variables demonstrated the explanatory power of 13.9% of the emotional labor. Based on the findings, emotional labor of radiation therapist was correlated with occupational professionalism. These results suggest that the intervention program intervening emotional labor should be continued to develop in order to improve the effective self-leadership, organization culture and distress factor.

KEPCO 전력연구원에서 개발한 고효율 습식 아민 CO2 흡수제(KoSol-4)를 적용하여 Test bed 성능시험을 수행하였다. 국내에서는 처음으로 석탄화력발전소에서 발생되는 연소 배가스를 적용하여 하루 2톤의 CO2를 처리할 수 있는 연소 후 CO2 포집기술의 성능을 확인하였으며 또한 국내에서는 유일하게 공정운전에 소요되는 재생에너지 소비량을 실험적으로 측정함으로써 KoSol-4 흡수제의 성능에 대한 신뢰성 있는 데이터를 제시하였다. 흡수제 순환량 및 재생탑 운전압력을 대 상으로 한 변수 실험 결과 Test bed 연속운전은 안정적으로 수행되었고, 흡수탑에서의 CO2 제거율은 국제에너지기구 온 실가스 프로그램(IEA-GHG)에서 제시하는 CO2 포집기술 성능평가 기준치(CO2 제거율: 90%)를 안정적으로 유지하였다. 또한 흡수제(KoSol-4)의 재생을 위한 스팀 사용량(재생에너지)은 3.0~3.2 GJ/tCO2이 소비되는 것으로 산출되었는데 이는 기존 상용 흡수제(MEA, Monoethanolamine)의 재생에너지 수준(약 4.09 GJ/tCO2, 본 연구) 대비 약 25% 이상 저감된 수 치일 뿐만 아니라 우리나라에서 연구 중인 모든 CO2 포집기술을 통틀어 가장 우수한 성능이다. 본 연구를 통해 KEPCO 전력연구원에서 개발한 KoSol-4 흡수제 및 공정의 우수한 CO2 포집 성능을 확인할 수 있었을 뿐만 아니라, 향후 고효율 흡수제(KoSol-4)를 상용 CO2 포집플랜트에 적용할 경우 CO2 포집비용을 크게 낮출 수 있을 것으로 기대되었다.

A pilot plant for CO 2 recovery of 2 ton-CO 2 /day from flue gas emitted from a 500 MW coal fired power plant was tested with aqueous amine absorbents. Based on a chemical absorption/regeneration process with 30 wt% aqueous monoethanolamine (MEA) solution, we studied the CO 2 recovery as a function of flow rate and input location of absorbent, pressure and temperature of stripper, and temperature of flue gas. Experimental data include the temperature profile of the absorber/stripper and CO 2 lean/rich loading values, which remained stable during the operation. We evaluated the energy requirement for regeneration of aqueous amine and the degree of CO 2 removal. While regeneration energy of aqueous amine increased with an increase in flue gas temperature and stripper pressure, it decreased with an increase in injection height of absorbent. The optimum point in flow rate of absorbent was 1300 kg/h in 350 Sm 3 /h flue gas. The regeneration energy using 30 wt% MEA solution was 3.92 GJ/ton CO 2 in 90% CO 2 removal, flue gas temperature of 40 °C, stripper pressure of 0.5 kgf/cm 2 and L/G ratio of 3.7 kg/Sm 3 . In addition, corrosion rate of the pilot plant were measured in six points. It is the largest as 79.11 mpy in the bottom of the stripper tower.

This study Seoul, Kyonggi area hospital and data were collected from 211 people in radiation therapy technologist. The collected data were analyzed by using SPSS 17 version, For verification of the differences among groups, coefficient of Pearson was executed. It was composed of social demographic characteristics, Job stress and the impact the organization effectiveness and reliability analysis of factors. Organization culture and self leadership of each of the types to classify the results of conducted analysis factors are as follows: And the difference in the gender, age, and satisfaction with the Organization. Organization commitment and working in accordance with each part working experience is different. Radiation therapy duties analysis results of correlation between the uniqueness. Job satisfaction(p

In this study, a performance analysis of a 500 MWe coal-fired power plant with a post-combustion CO2 capture system was performed. The amine-based chemical absorption process was considered as a base CO2 capture system. Based on the design conditions of the flue gas from the supercritical coal-fired power plant operating in the Republic of Korea, the energy consumption of the CO2 capture system was simulated using a process simulator. The simulation of the CO2 capture system was undertaken using Aspen Plus software with ELECNRTL property packages; based on these results, the energy requirement of the CO2 capture system and the overall efficiency of a power plant with the CO2 capture system was estimated. It was observed that the thermal energy required to regenerate the solvent reduces the efficiency of the power plant by 8.36%, the energy required to compress the CO2 from 0.1 to 11 MPa is the next largest factor, reducing the efficiency by 3.59%, and the other energy requirement amounts to 0.45%.

화학흡수법을 이용한 CO2 포집 공정에서 발생되는 아민계 흡수제의 휘발은 대기 환경에 좋지 않은 영향을 미칠 뿐 만 아니라 공정 운용에 있어 흡수제 손실을 보충하기 위한 비용의 증가를 초래하게 되므로 이에 대한 정확한 특성을 파악하는 것이 중요하다. 본 연구에서는 이를 위해 자체 고안한 휘발도 측정 장치를 활용하여 주요 아민 수용액 (MEA(monoethanolamine), MDEA(n-methyldiethanolamine), Pz(piperazine), AMP(2-amino-2-methyl-1-propanol), 2- MP(2-methylpiperazine), DGA(diglycolamine))의 휘발도를 측정하고, 가스크로마토그래피 장치를 활용한 정량적인 비 교를 통해 다양한 온도 조건과 CO2 부하 변화에 따른 휘발도의 영향을 분석하였다. 실험결과 MDEA＜DGA＜Pz＜2- MP＜MEA＜AMP 순으로 휘발도가 증가되었는데, 헨리상수가 큰 아민계 흡수제일수록 상대적으로 높은 휘발도를 보였으며 또한 반응온도가 상승하면 휘발도가 증가함을 확인하였다. 아민급수와 휘발도간의 상관관계 분석에서는 1차 아 민 중 DGA를 제외한 MEA 및 AMP가 3차 아민대비 휘발도가 높았으며, 3차 아민인 MDEA의 경우에는 반응온도 및 CO2 부하 조건에 따른 실험에서 휘발도가 매우 낮음을 확인할 수 있었다. 이는 MDEA의 분자 구조 내에 하이드록실기(-OH)가 2개 있어 높은 친수성으로 인하여 휘발이 거의 되지 않았고, 이에 비해 MEA 및 AMP는 하이드록실기 (-OH)가 1개이고, AMP의 경우 소수성기인 알킬기(-CH3)가 2개 있어 가장 많이 휘발된 것으로 판단된다.

Density functional theory (DFT) calculations of nucleophili-city do not consider steric hindrance around the nitrogenatoms in amines. Consideration of accessibility is required toestimate the reactivity of amines better. It can be included bycounting the number of collisions between reactive centers(N in amine, and C in CO

In this study, performance and economic analysis of 500 MWe coal-fired power plant with capture process was performed. For this purpose, chemical absorption method which is commercially available and most suitable for thermal power plant was studied and a criteria for technical and economic assessment of power plants suggested by IEA Greenhouse Gas R&D Programme was used. And we performed the sensitivity analysis focused on regeneration energy which exceed half of the total capture energy. Based on MEA(Monoethanoleamine) as a main chemical solvent and 3.31 GJ/ton regeneration energy in the stripper, net power efficiency was reduced from 41.0% (no capture) to 31.6%(with capture) and the cost of avoided was estimated 43.3 $/ton. And in case of 2.0 GJ/ton regeneration energy, the cost of avoided was calculated as 36.7 $/ton.

Chemical absorption method using amine based absorbents is the most applicable to post-combustion carbon dioxide capture process in thermal power station. The development of absorbent for CO 2 capture is the one of the core technologies in the manner of chemical absorption. To develop post-combustion carbon dioxide absorbents, IEA CCC suggested the requirements for excellent chemical absorbents such as higher carbon dioxide capacity, faster absorption and stripping rates, lower corrosivity and degradation rates, lower volatility, and reduced regeneration energy. In this study, Regeneration energy of KoSol-3 was 2.82 GJ/t- CO 2 . This value is lower than the value for the commercially used absorbent (MEA, 3.85 GJ/t- CO 2 ). These results mean that it is possible to reduce nearly 30% of regeneration energy when we use KoSol-3 as the carbon dioxide absorbent.

The effect of corrosion inhibitors such as CuCO3, CuSO4, and Na2SO3 on the oxidation of MEA has been investigated. The products of oxidative degradation of MEA were analyzed with or without the corrosion inhibitors. The corrosion inhibitor effects on the oxidative degradation of MEA and the extent of oxidative degradation is in the order CuCO3 > CuSO4 > MEA without inhibitors > Na2SO3. There was no difference in absorption/desorption rates among MEA solutions with and without the corrosion inhibitors. Among the products of the oxidative degradation of MEA, formate and acetate were dominant degradation products and nitrites and nitrates were also present in large amounts. The corrosion inhibitors CuCO3 and CuSO4 acted as catalysts for oxidative degradation of MEA. CuCO3 and CuSO4 influenced the formation of carboxylic acids (formate, acetate, and oxalate), but did not influence the formation of nitrogen products (nitrites and nitrates). Na2SO3 slightly inhibited the oxidative degradation of MEA and did not produce more oxidation products than CuCO3 and CuSO4.

A bench scale unit (2 m3N/h) for removing CO2 from flue gas was operated. Based on a chemical absorption/regeneration process with aqueous monoethanolamine (MEA) solution, we have evaluated the energy requirement for regeneration and degree of CO2 removal as a function of reboiler temperature, MEA concentration, CO2 concentration in the flue gas and ratio of the flow rate of liquid and flue gas. For verification of the experimental results from the bench scale CO2 capture unit, we have also calculated the regeneration energy by the summation of the reaction enthalpy of CO2, the sensible heat and the heat of vaporization of MEA solution and have compared these results with those of bench scale tests. It was observed that the regeneration energy using a 30 wt% MEA solution was 4.29 GJ/ton CO2 (experiment) and 4.55 GJ/ton CO2 (estimation), respectively. Also, the degree of CO2 removal increases with an increase in reboiler temperature and ratio of the flow rate of liquid and flue gas, while CO2 regeneration energy decreases with an increase in MEA concentration and CO2 concentration in the flue gas.

DFT calculations using a PCM solvation model were carried out to examine the reaction pathways for the formation of carbamate from CO2 and monoethanolamine (MEA) in the presence of an additional proton acceptor, MEA or H2O. In both cases, the zwitterionic species [HO(CH2)2NH2+—COO−] has a lower energy than the reactants. Proton transfer from the zwitterionic species to the base (MEA) produced a carbamate product with an accompanying gradual decrease in energy. However, a similar process for the water case resulted in an implausible increase in energy, which suggests that MEA is suitable as a base but H2O is not.

A pilot plant of 2 ton-CO 2 /day for CO 2 recovery from flue gas emitted from 250 MW LNG based power plant was tested with aqueous absorbents. The absorbent tested were of different nature such as primary amine (MEA), blend of primary, secondary, tertiary and sterically hindered amine such as MDEA + HMDA, AEPD + DPTA, and TIPA + DPTA. We have studied the CO 2 recovery as function of temperature, concentration, and flow rate of absorbent, pressure and temperature of stripper, and flow rate and temperature of flue gas. It was observed that while CO 2 recovery increases with increase in flow rate and concentration of absorbent, it decreases with increase in temperature and flow rate of flue gas. The CO 2 recovery ratio increases with increase in stripper temperature and decrease in stripper pressure. CO 2 loading (mol CO 2 /mol amine) also decreases with increase in stripper temperature. For the absorbent flow rate greater than 2.4 N m 3 /h, the carbon dioxide recovery ratio follows the sequence: MEA > MDEA + HMDA > AEPD + DPTA > TIPA + DPTA.

In this paper, density, viscosity, surface tension and vapor pressure of aqueous sodium glycinate solutions of different mass fractions (0.1–0.5) at different temperatures (20–100°C) were simulated using Pro/II (version 6.01), a commercial process simulator, and compared with corresponding experimentally measured data. It was found that simulated data of physicochemical properties compared well with corresponding experimental data. We have also predicted concentration of CO2 with each ideal stage in an absorber/stripper tower.

can produce eventually sulfuric acid after oxidationand reaction with water, it is considered as one of the mainsources causing acid rain. To prevent the environmentallyharmful gas from exposing to atmosphere, the flue gas de-sulfurization (FGD) processes such as limestone-scrubbingand chemical absorption are requested in the fire powerplant. Currently, among many sorbents limestone (CaCO

The study tried to comparatively analyze surgical findings based on the examination results of polysomnography and video-fluoroscopy which are examinations useful in diagnosis of obstructive sleep apnea syndrome. The subjects were patients over the age of 18 who were admitted for snoring, observed apnea, or sleepiness. Received under polysomnography and video-fluoroscopy inspection of obstructive sleep apnea of doubt from March 2013 to February 2014, it was intended for patients who have undergone surgical treatment. In the analysis was obstructive sleep apnea severity, there were difference in all clauses excluding age and height (P

The solubilities of carbon dioxide in aqueous solutions of tertiary amine, i.e. triisopropanolamine, have been measured at 313.15, 323.15, and 333.15 K and over the partial pressures of carbon dioxide ranging from 1 to 3000 kPa. The treated concentrations of aqueous triisopropanolamine solutions are 10 and 30 mass%. The solubilities of carbon dioxide in aqueous 30 mass% TIPA at 333.15 K were compared with those in aqueous solutions of MEA and MDEA.

This work was supported by Grant 2000-C-CD02-P-01 from the Korea Energy Management Corporation R&D Headquarter and also partially by the Brain Korea 21 Project.

Chemical reaction kinetics of CO2 with a sterically hindered amine, 2-amino-2-ethyl-1,3-propanediol (AEPD), in aqueous solutions has been studied by a wetted-wall column absorber. Three reaction temperatures of 305.15, 313.15, and 318.15 K and AEPD concentration ranges from 5 to 25 wt % APED were chosen. Specific absorption rates as a function of CO2 partial pressure in aqueous AEPD solutions were measured as well. The N2O analogy was applied to estimate the physicochemical properties of CO2 in amine solutions. Based on the zwitterion mechanism, the zwitterion deprotonation and second-order rate constants were calculated and presented at each temperature. The second-order rate constants, k2, were found to be 378, 855, and 1278 m3·kmol-1·s-1 at 303.15, 313.15, and 318.15 K, respectively.

The densities and viscosities of aqueous solutions of 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) were measured over the temperature range from (303.15 to 343.15) K and at the AHPD concentrations (5, 10, 15, 20, and 25) mass %. The solubilities of carbon dioxide in aqueous AHPD solutions were also measured at (313.15, 323.15, and 333.15) K over partial pressures of carbon dioxide ranging from (1 to 2000) kPa. The concentrations of aqueous AHPD solutions were (10 and 20) mass %. The thermodynamic characteristics of aqueous AHPD solution as a potential CO2 absorbent were identified through measurements of these three key properties.

A variety of 2-allylated-5-substituted tetrazoles were prepared in excellent yields through the reaction of alkyl- and arylidenemalononitriles, allyl acetates and trimethylsilyl azide in the presence of a palladium catalyst.

The synthesis of tetrazoles was achieved via the palladium-catalyzed three component coupling (TCC) reaction; The TCC reaction of malononitrile derivatives, allyl acetate and trimethylsilyl azide proceeds very smoothly under a catalytic amount of Pd(PPh3)4 to give 2-allyltetrazoles, and further the TCC reaction of various activated cyano compounds, allyl methyl carbonate and trimethylsilyl azide proceeds readily under a catalytic amount of Pd2(dba)3 x CHCl3 and (2-furyl)3P to give 2-allyltetrazoles. pi-Allylpalladium azide complex is proposed as a key intermediate in the catalytic cycle and the [3 + 2] cycloaddition between the pi-allylpalladium azide complex and cyano compounds most probably gives the tetrazole frameworks. The deallylation of the derived allyltetrazoles was attained via the two-step procedure; the ruthenium-catalyzed isomerization and ozonolysis.

Palladium-catalyzed intemolecular reaction of imines 1 with vinylic oxiranes 2 gives the regioselective [3 + 2] cycloaddition products, 1,3-oxazolidine derivatives 3 , in good to excellent yields. The present reaction permits the use of unconventional starting materials for the synthesis of 1,3-oxazolidines 3 .

The reaction of certain activated olefins (Michael acceptors) 5 with vinylic oxiranes 1 in the presence of catalytic amounts of Pd(PPh3)4 (5 mol %) in THF at 40 °C gave the corresponding [3 + 2] cycloaddition products 6. In all cases the reactions proceeded in regioselective manner, affording the corresponding polysubstituted tetrahydrofuran derivatives. The nature of electron-withdrawing group in activated olefins affected significantly the reactivity of substrates. Michael acceptors having sterically less bulky electron-withdrawing groups were essential for the cycloaddition reaction, and the presence of two electron-withdrawing groups at the α-position was needed. Accordingly, activated olefins having (CN, CN), (CN, CO2Et), (CN, SO2Ph), (Meldrum's type), and (SO2Ph, SO2Ph) could be used as a Michael acceptor. The present reaction provides a new method for the synthesis of tetrahydrofuran derivatives from vinylic oxiranes and Michael acceptors.

1,2,6-Hexanetriol reacts with aromatic primary amines in the presence of ruthenium complex catalyst, RuCl2(PPh3)3, to give selectively 1-substituted-3-hydroxyperhydroazepines in good yields.