• Title/Summary/Keyword: Pre-equilibrium

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Neutron Cross Section Evaluation on Pr-141, Nd-143, Nd-145, Sm-147 and Sm-149

  • Lee, Y. D.;J. H. Chang
    • Nuclear Engineering and Technology
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    • v.34 no.4
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    • pp.370-381
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    • 2002
  • The neutron induced nuclear data for Pr-141, Nd-143, Nd-145, Sm-147 and Sm-149 were calculated and evaluated from 10 keV to 20 MeV. The energy dependent optical model potential parameters were extracted based on the recent experimental data and applied up to 20 MeV. The s-wave strength function was calculated. Spherical optical model , statistical model in equilibrium energy, multistep direct and multistep compound model in pre-equilibrium energy and direct capture model were introduced in Empire calculation. The theoretically calculated cross sections were compared with the experimental data and the evaluated files. The model calculated total and capture cross sections were in good agreement with the reference experimental data. The capture cross sections in pre-equilibrium were enhanced in recent released Empire version. The evaluated cross section results were compiled to ENDF-6 format and will improve the ENDF/B-Vl.

A Study on Adsorption Characteristics of the Heavy Metals using Melting Slag of Incinerator Ash (소각재 용융슬래그를 이용한 중금속 흡착특성에 관한 연구)

  • Yoo, Seung-Chol;Kim, Hwan-Gi
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.4
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    • pp.413-420
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    • 2008
  • In order to utilize cinder melting slag as a filter media to control the quality of early rainwater, its environmental stability was verified by heavy metal elution experiment and improved by pre-treatment. Possibilities of improving its function as an absorbent was considered. Absorption characteristics of melting slag before and after the pre-treatment were analyzed by heavy metal equilibrium and stationary-phase column experiments, which in turn were analyzed by comparison experiment with activated carbon. As a result of heavy metal elution experiment, every metal item existed in a much lower amount than the criteria or was not detected, implying that there is no problem recycling it. Absorption equilibrium experiment showed that the time for pre-treatment melting slag to reach the equilibrium was reduced, while the absorbed amount was greatly increased. Stationary-phase column experiment assures us that the elimination rate was not changed much by influx rate, pH and the change in packing volume rate, indicating that this melting slag can be used not only as a filter media to control the quality of early rainwater but also in many areas of water-processing.

Equilibrium Stress Mode Determination of Tensegrity Structure by CAD (CAD를 이용한 텐세그리티 구조물의 평형응력모드 결정법)

  • Kim, Jae-Yeol
    • Journal of Korean Association for Spatial Structures
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    • v.12 no.2
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    • pp.81-88
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    • 2012
  • Cable dome structures are composed of cables-masts and the cables should be in pre-tension since a structure without pre-tension is not stable. Under the pretension, self equilibrium stress state is the main characteristic of a cable dome structure. In this paper, a new method based on the basic principle of closed force polygon for equilibrium system is proposed for the determination of self-equilibrium mode of cable dome structure. The proposed method which is called geometric method has the unique characteristic of visualization of the force mode needed for maintenance of self-equilibrium. The basic theory for a self equilibrium of structure is that the summation of forces at each joint without any external load should be zero. The simplicity of the method which involves only drawing close polygon with the aid of suitable CAD software has been illustrated by means of a example. The results compared with mechanical calculation and existed method and shows good agreement.

The Effects of Mass Loss on the Pre-Main Sequence Evolutionary Tracks of Stein's Model Stars

  • Um, In-Kyung
    • Publications of The Korean Astronomical Society
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    • v.1 no.1
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    • pp.1-8
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    • 1984
  • Under the context of Stein's linear theory of stellar models, the luminosity-effective temperature relationship is derived for contracting pre-main sequence stars which are losing mass, according to the empirical formula, given by Reimers (1975). The effects of mass loss on their evolution are investigated by calculating evolutionary tracks of 1. $1.5M_{\odot}$, $5M_{\odot}$, and $10M_{\odot}$, stars. Our calculations reveal that the effects of mass loss show up in the radiative equilibrium stage of the evolution. It is found that an increase of mass loss rate leads to delay the onset of radiative equilibrium, thus resulting in under-luminous main sequence stars. It is also noted that the mass loss prolongs the pre-main sequence life time. Detailed results of the calculations are discussed.

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Simulation of Pre-burner Performance in Liquid-fueled Rocket Engine for Satellite Launch Vehicle (위성 발사체 액체 로켓 엔진의 Pre-burner 성능 모사)

  • Shin, Ji-Chul;Jung, Tae-Kyu;Lee, Soo-Yong
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.36 no.12
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    • pp.1180-1185
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    • 2008
  • In-house code which simulates the performance of pre-burner in staged-combustion liquid-fueled rocket engine was developed and demonstrated. Chemical reaction of pre-burner was modeled based on analytic algorithm of CEA (Chemical Equilibrium with Applications) and gas dynamics model was incorporated with it. Comparison results between in-house code and CEA have shown small relative errors except at very high or very low O/F ratio. Also the performance curve obtained by in-house code revealed that the calculated values follow the overall trend of real engine (RD-8) performance quite well and at steady-state operation, the deviation became very small.

Effects of load height application and pre-buckling deflections on lateral buckling of thin-walled beams

  • Mohri, F.;Potier-Ferry, M.
    • Steel and Composite Structures
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    • v.6 no.5
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    • pp.401-415
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    • 2006
  • Based on a non-linear model taking into account flexural-torsional couplings, analytical solutions are derived for lateral buckling of simply supported I beams under some representative load cases. A closed form is established for lateral buckling moments. It accounts for bending distribution, load height application and pre-buckling deflections. Coefficients $C_1$ and $C_2$ affected to these parameters are then derived. Regard to well known linear stability solutions, these coefficients are not constant but depend on another coefficient $k_1$ that represents the pre-buckling deflection effects. In numerical simulations, shell elements are used in mesh process. The buckling loads are achieved from solutions of eigenvalue problem and by bifurcations observed on non linear equilibrium paths. It is proved that both the buckling loads derived from linear stability and eigenvalue problem lead to poor results, especially for I sections with large flanges for which the behaviour is predominated by pre-buckling deflection and the coefficient $k_1$ is large. The proposed solutions are in good agreement with numerical bifurcations observed on non linear equilibrium paths.

Effects of Sensory Integration Training on Equilibrium Ability in the College Students of the Twenties (감각통합훈련이 20대 대학생들의 균형능력에 미치는 효과)

  • Han, Jong-Man;Lee, Woo-Hyung
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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    • v.16 no.1
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    • pp.37-42
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    • 2010
  • Purpose : The purpose of this study was to evaluate the influence of sensory integration training on equilibrium ability in the college students of the twenties. Methods : The sensory integration training group(male: n=10, female: n=9) was measured an equilibrium ability by Kinesthetic Ability Trainer(KAT) at pre-intervention and post-intervention in 4weeks. Results : Mean value of eye close both leg standing and eye close one leg standing tests of the sensory integration training group were significantly reduced among the intervention period(p<.05). Conclusion : We were found that sensory integration training could reduce mean value of eye close both leg standing and eye close one leg standing tests and improve a balance for the college students of the twenties.

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The Role of Ca Equilibrium on the Functional Properties of Cheese: A Review

  • Lee, Mee-Ryung;Lee, Won-Jae
    • Food Science of Animal Resources
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    • v.29 no.5
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    • pp.545-549
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    • 2009
  • The functional properties of cheese, such as texture and melt, are known to be controlled by several important parameters. Recently, the characteristics of Ca in cheeses, especially the form of Ca (insoluble (INSOL) or soluble) and the shift in Ca equilibrium (i.e., from INSOL to soluble Ca), during aging has received a lot of attention. The INSOL form of Ca, which is present as a structural form in casein, plays a critical role in determining the functional properties of cheese during the early period of ripening (~1 mon). It seems that there is always a reduction of INSOL Ca content in cheese during ripening and there are also factors that can affect the shift in Ca equilibrium. These factors may include the composition of cheese milk, cheese manufacturing pH, acid development during aging, adopting curd-washing in various methods, pre-acidification of milk, etc. There have been many studies showing that the rheological and melting properties of cheese during ripening were significantly (p<0.05) affected by the shift in Ca equilibrium. Therefore, for cheese makers, it is now possible to predict/manage the functional properties of cheese by monitoring and controlling Ca equilibrium in cheese during aging.

Purification and Characterization of Bacillus subtilis Protoporphyrinogen Oxidase and Pre-equilibrium Behavior During Oxidation of Protoporphyrinogen IX

  • Jeong, Eun-Ju;Han, Ok-Soo
    • BMB Reports
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    • v.34 no.1
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    • pp.39-42
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    • 2001
  • Previous studies indicate that B. subtilis protoporphyrinogen oxidase is poorly inhibited by diphenyl ether herbicides. To better understand the basis of this insensitivity, the enzyme was overexpressed as a soluble protein in E. coli, purified and characterized. The mechanism of oxidation of B. subtilis protoporphyrinogen IX was studied and the enzyme kinetic parameters were determined for protoporpyrinogen IX; $K_m$, and $k_{cat}$ were $6.3\;{\mu}M$ and $0.028\;h-^1$, respectively. The enzyme required flavin adenine dinucleotide as a cofactor and its activity was enhanced by 1 mM n-octylglucopyranoside. The nonenzymatic oxidation rate was dependent on the concentration of protoporphyrinogen IX, suggesting that the reaction involves a pre-equilibrium step followed by a rate-limiting step.

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Salt-Induced Protein Precipitation in Aqueous Solution: Single and Binary Protein Systems

  • Kim, Sang-Gon;Bae, Young-Chan
    • Macromolecular Research
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    • v.11 no.1
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    • pp.53-61
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    • 2003
  • A molecular-thermodynamic model is developed for the salt-induced protein precipitation. The protein molecules interact through four intermolecular potentials. An equation of state is derived based on the statistical mechanical perturbation theory with the modified Chiew's equation for the fluid phase, Young's equation for the solid phase as the reference system and a perturbation based on the protein-protein effective two body potential. The equation of state provides an expression for the chemical potential of the protein. In a single protein system, the phase separation is represented by fluid-fluid equilibria. The precipitation behaviors are simulated with the partition coefficient at various salt concentrations and degree of pre-aggregation effect for the protein particles. In a binary protein system, we regard the system as a fluid-solid phase equilibrium. At equilibrium, we compute the reduced osmotic pressure-composition diagram in the diverse protein size difference and salt concentrations.