• 자원리싸이클링
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• 제17권2호
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• pp.63-69
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• 2008

폐알칼리망간전지 분말에 대한 $Ni^{2+}$의 흡착 거동을 살펴보기 위하여 흡착제의 양, 홉착질의 초기농도 및 반응온도를 변화시켜 가며 그 특성을 조사하였다. $Ni^{2+}$의 흡착반응은 유사이차반응속도를 잘 따르는 것을 알 수 있었으며 $Ni^{2+}$의 초기농도가 증가함에 따라 유사이차반응속도상수($k_2$)는 감소하는 것으로 나타났다. 흡착평형을 표현하는데 널리 이용되는 Langmuir와 Freundlich 흡착 모델에 평형흡착 결과를 적용하였으며 Freundlich isotherm모델에 적합한 것으로 나타났다. 반응온도가 증가함에 따라 평형흡착량이 증가하여 흡착반응은 흡열반응의 양상을 보였으며 온도의 변화에 대한 실험결과로부터 ${\Delta}H^{\circ},\;{\Delta}G^{\circ}$ 그리고 ${\Delta}S^{\circ}$ 열역학적 변수를 도출하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제23권4호
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• pp.543-551
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• 1999

Diesel engine is a major source of the air pollution. In general the concentrations of these pollu-tants in diesel engine exhaust differ from values calculated assuming chemical equibrium. Thus the detailed chemical mechanisms by which these pollutions form and the kinetic of these process-es are important in determining emission levels. In this study the computer program has been developed to calculate the required thermodynam-ic properties of combustion products(10 spacies) for both equilibrium and non-equilibrium in cylin-der for diesel engines. Nitric oxide emissions are calculated by using the extended Zeldovich Kinet-ic mechanism with a steady state assumption for the N concentration and equilibrium values used for H, O, $O_2$ and OH concentrations. By the results it is confirmed that developed simulations program with the NO prediction model is validated against residual mass fraction combustion index of Wiebe's functions pre-mixed com-bustion ration fuel injection timing.

• 자원리싸이클링
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• 제15권4호
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• pp.13-18
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• 2006

본 연구는 Gd 용액을 대상으로 추출시간, 평형 pH와 초기농도의 변화를 통하여 HEH/EHP를 함유한 추출수지의 추출특성을 파악하고자 하였다. 추출수지를 사용하여 Gd을 추출시 추출시간은 90분 정도가 적절한 것으로 판단된다. 추출율(%)은 평형 pH $1.0{\sim}2.0$ 사이에서 평형 pH가 증가할수록 증가하였다. 평형에서 Freundlich 흡착등온식을 사용하여 계산된 측정값과 예측값이 잘 일치하였다.

• 대한약리학회지
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• 제30권2호
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• pp.255-260
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• 1994

There are some reports about the influences of free fatty acids on the albumin binding of drugs. But they were concerned to the limited free fatty acids, mostly of azapropazone-warfarin bidning site bound drugs and determination of dissociation and association constants by stopped flow technique. These data were not enough to make conculsions for the general tendency of free fatty acid to albumin binding. Therefore the influence of various saturated fatty acids of $C_{10{\sim}20}$, oleic acid and linoleic acid as unsaturated fatty acids to albumin binding of warfarin and dansylsarcosine were studied by equilibrium dialysis. The concentration of free drug was determined by spectrophotometer according to the molar ratios of 0, 0.5, 1, 2 and 4 between free fatty acid and albumin. There were significant increasing in the free durg concentration of warfarin and dansylsarcosine when the molar ratio for capric acid, lauric acid and palmitic acid was 4. The free warfarin concentration was increased significantly at a molar ratio of 4 between oleic acid and albumin. Therefore the albumin binding of durgs can be variated significantly by increased free fatty acid of diabetics and cause to the pharmacokinetic variation between healthy and diabetics.

• 상하수도학회지
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• 제25권3호
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• pp.359-366
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• 2011

The feasibility of using volcanic ash for lead ion removal from wastewater was evaluated. The adsorption experiments were carried out in batch tests using volcanic ash that was treated with either NaOH or HCl prior to the use. Volcanic ash dose, temperature and initial Pb(II) concentration were chosen as 3 operational variables for a $2^3$ factorial design. Ash dose and concentration were found to be significant factors affecting Pb(II) adsorption. The removal of Pb(II) was enhanced with increasing volcanic ash dose and with decreasing the initial Pb(II) concentration. Pb(II) adsorption on the volcanic ash surface was spontaneous reaction and favored at high temperatures. Calculation of Gibb's free energy indicated that the adsorption was endothermic reaction. The equilibrium parameters were determined by fitting the Langmuir and Freundlich isotherms, and Langmuir model better fitted to the data than Freundlich model. BTV(base-treated volcanic ash) showed the maximum adsorption capacity($Q_{max}$) of 47.39mg/g. A pseudo second-order kinetic model was fitted to the data and the calculated $q_e$ values from the kinetic model were found close to the values obtained from the equilibrium experiments. The results of this study provided useful information about the adsorption characteristics of volcanic ash for Pb(II) removal from aqueous solution.

• 한국지반공학회지:지반
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• 제11권2호
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• pp.121-138
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• 1995

여러종류의 화합물질들이 동시에 토양에 유출되었을 때 이들이 토양에 흡착하는 정도를 예측 함에는 Langmuir Competitive Model과 IAS(Ideal Adsorption Model) 등이 널리 사용되고 있 는데, 5개의 유기화합물질(Phenol, 2,4-Dichlorophenol, 2,4,6-Trichlorophenot Brucine, Thiourea)과 2종류의 토양을 이용한 흡착실험을 통해서 이 Model들의 예측도를 비교분석하였다. 흡착실험은 이 화합물질들이 독자적인 상태에서 그리고 혼합상태에서 각각 구분하여 실헙하였다. 일반적으로 IAS Model이 Langmuir Model보다 혼합상태에서 각 구성 화합물질들의 흡착을 더 정확히 예측하였다. Langmuir Model은 Phenol과 함께 섞여있는 다른물질의 농도가 높을 때 Phenol의 흡착을 낮게 예측하였다. 두가지 Model모두 Thiourea가 혼합상태에 있을때 흡착정도를 만족스럽게 예측하지 못했는데 Thiourea는 Aliphatic화합물이고 나머지 4개는 Aromatic화합물이다.

• Food Science and Biotechnology
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• 제18권3호
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• pp.618-623
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• 2009

Synergistic interactions between xanthan (X) and carob (C) were investigated by studying the linear viscoelastic behavior of X, C, and X/C mixtures at sol and gel states. At the solution state, storage modulus (G') dominates the linear viscoelastic properties of X/C mixtures. The gelation temperature (52 to $57^{\circ}C$) was weakly dependent on the xanthan fraction (${\phi}x$) in the mixture. The ${\phi}x$ also had a strong effect on G' until ${\phi}x=0.5$. The elastic active network concentration (EANC) of X/C gels was estimated from the pseudo-equilibrium modulus. The EANC for systems with ${\phi}x=0.25$, 0.5, 0.75, and 1 at 1% total concentration was 2.3, 4.4, 4.1, and 0.32 (${\times}10^{-3}\;mol/m^3$), respectively. The maximum synergistic effect was observed at about ${\phi}x=0.5$. The G' at the transition state of X/C mixed gel was proportional to ${\omega}^{3/2}$ at ${\omega}$>${\omega}_{tr}$ (the onset transition frequency) compared to the theoretical limit of ${\omega}^{1/2}$.

• Applied Biological Chemistry
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• 제35권5호
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• pp.399-403
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• 1992

무의 염절임 과정에서 일어나는 염의 침투와 관련하여 무의 응력완화 변화를 측정하고 점탄성의 변화를 제시하였다. 침지 염용액의 농도와 침지온도가 증가할수록 염의 확산은 더 잘 일어났으나 염용액의 온도에 따른 염의 침투 정도는 낮은 염용액의 농도에 의해서 더 많은 영향을 미쳤다. 염장하지 않은 무의 높은 조직의 강도와 점탄성은 염용액의 온도를 증가시킴에 따라 초기 응력에 대한 조직의 강도약화를 보여 주었으며 응력완화의 정도도 빨라졌고 평형상태에서 잔여응력 양도 감소하였다. 또한 염용액의 농도가 증가할수록 무 조직의 응력완화정도와 잔존응력양의 변화가 거의 일치함을 보였다. 염용액의 온도와 농도를 증가시킴에 따라 염절인 무조직의 점탄성 성분들도 낮아졌는데, 온도에 따른 무의 점탄성의 낮아지는 정도는 염침투나 초기응력과 마찬가지로 낮은 염용액의 농도에서 더 많은 영향을 받았다.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.318-329
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• 2016

Reducing critical boron concentration in a commercial pressurized water reactor core offers many advantages in view of safety and economics. This paper presents a preliminary investigation of a reduced-boron pressurized water reactor core to achieve a clearly negative moderator temperature coefficient at hot zero power using the newly-proposed "Burnable absorber-Integrated Guide Thimble" (BigT) absorbers. The reference core is based on a commercial OPR1000 equilibrium configuration. The reduced-boron ORP1000 configuration was determined by simply replacing commercial gadolinia-based burnable absorbers with the optimized BigT-loaded design. The equilibrium cores in this study were directly searched via repetitive Monte Carlo depletion calculations until convergence. The results demonstrate that, with the same fuel management scheme as in the reference core, application of the BigT absorbers can effectively reduce the critical boron concentration at the beginning of cycle by about 65 ppm. More crucially, the analyses indicate promising potential of the reduced-boron OPR1000 core with the BigT absorbers, as its moderator temperature coefficient at the beginning of cycle is clearly more negative and all other vital neutronic parameters are within practical safety limits. All simulations were completed using the Monte Carlo Serpent code with the ENDF/B-VII.0 library.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.53-53
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• 2010

Car industry has required light-weight steels, but still with strong mechanical strength. To meet this requirement, a variety of researches on Fe-Al alloys have been performed. As Al is being added in a disordered manner, alloys become more ductile and show higher yield stress. At a certain concentration of Al, however, the Fe-Al alloy system falls in a second phase whose mechanical strength is worsened. To understand the microscopic role of Al, we investigate the stability and the elastic properties of various Fe-Al alloys using ab initio density functional theory. At agiven Al concentration, the equilibrium geometry is obtained among several disordered Fe-Al alloy structures by performing the geometry relaxation. The formation energies and elastic properties such as bulk moduli of the equilibrium structures are also computed as a function of Al concentration. We also investigate the effects of different elements such as Si and Mn. Fe-Si alloy systems exhibit unusual mechanical behaviors requiring further investigation to understand their physical origin. Especially, the microscopic role of Mn is investigated to find its physical origin of preventing the Fe-Al alloy system from forming an unfavorable second phase. The effect of manganese on mechanical properties of Fe-based alloys is also explored.