• 제목/요약/키워드: Thermodynamic Characteristics

검색결과 355건 처리시간 0.028초

Characteristics of Southern Ocean Sea Ice Distribution Modeled Using Cavitating Fluid Rheology and Climatological Atmospheric Data

  • Yih, Hyung-Moh;Mechoso, Carlos R.
    • Journal of the korean society of oceanography
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    • 제34권2호
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    • pp.59-72
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    • 1999
  • Cavitating fluid sea ice model of Plato and Hibler (1992) is applied to the Southern Ocean with an idealized, circular Antarctica. Using climatological atmospheric forcing fields averaged in the zonal direction, we show that oceanic heat flux and ice velocity have major effects on the seasonal change of ice edge, as other studies showed. In our model results, there appears a zone of free drift that contains a polynya zone. Thermodynamic forcing functions make dominant contributions to daily increments of ice thickness and compactness, except the zones of ice edge and polynya. The dominant contributions are also shown in distributions of the temperature on ice surface and several to terms in surface heat balance equation, and are also confirmed by those obtained from the thermodynamic-only model with the different locations of ice edge.

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피발산비닐과 아세트산비닐의 공중합에 관한 이론적 고찰 (Theoretical Investigations on the Copolymerization of Vinyl Pivalate and Vinyl Acetate)

  • Ghim, Han-Do;Kim, Jae-Pil;Lyo, Won-Seok
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2002년도 봄 학술발표회 논문집
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    • pp.29-32
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    • 2002
  • Thermodynamics of copolymerization is one of the fundamental elements for studying the effects of copolymerization parameters on the copolymer characteristics. Up until now, it has not been easy work not because there are not effective models but because the known thermodynamic values are limited to some copolymer pairs. Recently, owing to the development of molecular modeling methods, some thermodynamic parameters can be calculated and estimated on computer. (omitted)

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이성분계(3차 부틸-히드로과산화물 + 기체) 클러스레이트 하이드레이트의 구조적 특성과 열역학적 안정성에 관한 연구 (Phase equilibria and structure identification of tert-butylhydroperoxide + gaseous clathrate hydrates)

  • 윤여범;차민준;권민철;이흔
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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    • pp.150.1-150.1
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    • 2011
  • Structure-II hydrate has been highlighted due to its higher gas storage capacity and favorable thermodynamic conditions. In this study, we introduce a new structure-II hydrate former, tert-butyl hydroperoxide (TBHP) and confirm the structural characteristics through High-Resolution Powder Diffraction (HRPD), $^{13}C$ solide-state NMR and Ramanspectroscopy. Here,we also investigated the thermodynamic stability of binary(TBHP+gaseous) clathrate hydrates. The experimental data were generated using an isochoric pressure-search method. The dissociation data for (TBHP +gaseous) clathrate hydrates are compared with the other hydrocarbon hydrate and pure gaseous hydrate.

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NON-GREY RADIATIVE TRANSFER IN THE PHOTOSPHERIC CONVECTION : VALIDITY OF THE EDDINGTON APPROXIMATION

  • BACH, KIEHUNN
    • 천문학회지
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    • 제49권1호
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    • pp.1-8
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    • 2016
  • The aim of this study is to describe the physical processes taking place in the solar photosphere. Based on 3D hydrodynamic simulations including a detailed radiation transfer scheme, we investigate thermodynamic structures and radiation fields in solar surface convection. As a starting model, the initial stratification in the outer envelope calculated using the solar calibrations in the context of the standard stellar theory. When the numerical fluid becomes thermally relaxed, the thermodynamic structure of the steady-state turbulent flow was explicitly collected. Particularly, a non-grey radiative transfer incorporating the opacity distribution function was considered in our calculations. In addition, we evaluate the classical approximations that are usually adopted in the onedimensional stellar structure models. We numerically reconfirm that radiation fields are well represented by the asymptotic characteristics of the Eddington approximation (the diffusion limit and the streaming limit). However, this classical approximation underestimates radiation energy in the shallow layers near the surface, which implies that a reliable treatment of the non-grey line opacities is crucial for the accurate description of the photospheric convection phenomenon.

Dynamic-Thermodynamic Sea Ice Model: Application to Climate Study and Navigation

  • Makshtas, Alexander;Shoutilin, Serger V.;Marchenko, Alexey V.;Bekryaev, Roman V.
    • Journal of Ship and Ocean Technology
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    • 제8권2호
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    • pp.20-28
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    • 2004
  • A dynamic-thermodynamic sea ice model with 50-km spatial and 24-hour temporal resolution is used to investigate the spatial and long-term temporal variability of the sea ice cover the Arctic Basin. The model satisfactorily reproduces the averaged main characteristics of the sea ice and the sea ice extent in the Arctic Basin and its decrease in early 1990th. At times model allows to suppose partial recovery of sea ice cover in the last years of twenty century. The employment of explicit form for description of ridging gives opportunity to assume that the observed thinning is the result of reduction the intensity of ridging processes and to estimate long-term variability of probability the ridge free navigation in the different parts of the Arctic Ocean including the North Sea Route area.

DPPC의 상전이에 미치는 Dammarane Series의 Triterpenoidal Glycoside와 그 Aglycone의 영향 (Effect of Triterpenoidal Glycosides of Dammarane Series and Their Aglycones on Phase Transitions of Dipalmitoylphosphatidylcholine)

  • Kim, Yu.A.;Park, Kyeong-Mee;Park, Hwa-Jin
    • Journal of Ginseng Research
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    • 제20권1호
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    • pp.23-29
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    • 1996
  • The effect of ginseng glycosides and their aglycones on the thermodynamic characteristics of membranes from dipalmitoylphosphatidylcholine (DPPC) was investigated. Total saponins (TS) from Korean red ginseng, Panax ginseng C.A. Meyer, interacted with the Eel Phase of lipid in the Polar region and did not penetrate the deeper glycerol backbone of lipid molecule. From the all investigated components of TS (aglycons and ginsenosides), only 20-(S)-panaxadiol (PD) had an effect similar to TS. High concentration of TS penetrated in hydrophobic Cl-C8 region. The presence of cholesterol did not influence the interaction of TS with DPPC. An elimination of transition, however, took place at 10~100 $\mu\textrm{g}$/ml of TS. DPPC had a low ability to interact with cholesterol (CHL) as compared with other lecithins except ethanolamine. From our results, only TS and PD, at high concentrations (100 mol%), influenced the phase transition of mixture of DPPC:CHL.

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Methodology for Describing Different Phase States of Molecular Nitrogen

  • Cho, Haeng Muk;Kudryavtsev, I.N.;Kramskoy, A.V.
    • 에너지공학
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    • 제23권4호
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    • pp.215-222
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    • 2014
  • A theory-based methodology for describing the thermodynamic properties of molecular nitrogen is presented. The results obtained indicate a successful application of a fully consistent statistical method for the description of a molecular system in different phase states. The method employs a density of states equation for solid nitrogen and a perturbation potential for gaseous and liquid nitrogen. The main characteristics of the calculation method include the need for a minimal number of initial data and the absence of fitting parameters. The adequacy of the physical model that is the basis for the method allows a description of existing experimental data and the peculiarities of the thermodynamic properties.

Mutation Effects on FAS1 Domain 4 Related to Protein Aggregation by Molecular Dynamics Simulations and Solvation Free Energy Analysis

  • Cho, Sunhee;Ham, Sihyun
    • EDISON SW 활용 경진대회 논문집
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    • 제4회(2015년)
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    • pp.70-75
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    • 2015
  • Fasciclin 1 (FAS1) is an extracellular protein whose aggregation in cornea leads to visual impairment. While a number of FAS1 mutants have been studied that exhibit enhanced/decreased aggregation propensity, no structural information has been provided so far that is associated with distinct aggregation potential. In this study, we have investigated the structural and thermodynamic characteristics of the wild-type FAS1 and its two mutants, R555Q and R555W, by using molecular dynamics simulations and three-dimensional reference interaction site model (3D-RISM) theory. We find that the hydrophobic solvent accessible surface area increases due to hydrophobic core repacking in the C-terminus caused by the mutation. We also find that the solvation free energy of the mutants increases due to the enhanced non-native H-bonding. These structural and thermodynamic changes upon mutation contribute to understand the aggregation of these mutants.

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플라스틱병을 이용한 빙축시스템의 열역학적 성능에 관한 연구 (A Study on the Thermodynamic Performance of Plastic Bottle Ice Storage System)

  • 이세균;김호연;이영덕
    • 설비공학논문집
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    • 제8권4호
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    • pp.484-496
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    • 1996
  • This paper presents an anlaysis on the thermodynamic performance of ice storage system. The primary interest in this work is the exergetic efficiency of the system. The ice storage system considered here is the capsule type system with the waste plastic bottle being used as a capsule. To examine the characteristics of irreversibility production and exergetic efficiency in detail the ice storage system to be analyzed has been separated from the refrigerator in this analysis. The analysis is based on the lumped model with 3 uniform temperatures. The results indicate that 3 dimensionless parameters can describe the exergetic efficiency of the system, from which the characteristics of irreversibilities and the ranges of these parameters to ensure the reasonable performance of the system can be found. Experiments also have been performed to demonstrate the feasibility of such a system. This analysis only shows the performance of ice storage side, with the refrigeration side excluded. However, the results can be interpreted as a total performance if the refrigerator coupled with the ice storage system operatres reversibly.

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Thermal Storage and Thermodynamic Characteristics of Phase Change Materials Slurries

  • Kwon, Ki-Hyun;Jeong, Jin-Woong;Kim, Jong-Hoon;Kim, Yong-Joo;Choi, Chang-Hyun
    • Food Science and Biotechnology
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    • 제18권6호
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    • pp.1392-1397
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    • 2009
  • This study was aimed at developing a low cost cold storage system for agricultural products. Three kinds of slurries: $K_1$, $K_2$, and $K_3$ slurries were developed using phase change materials (PCMs) such as tetradecane, octadecane, and sodium polyacrylate to maintain the desired temperature ranges. The slurries were manufactured by in-situ polymerization. Tetradecane and octadecane were capsulated in a core with melamine at the surface. The thermodynamic characteristics of the slurries were measured and analyzed. The latent heats of the $K_1$, $K_2$, and $K_3$ slurries at the melting points were 206.41, 186.88, and 147.91 kJ/kg, respectively. A transportable cold storage container was built to investigate the performance of the slurries as thermal storage media. The temperatures at the insides of the container could be maintained in the ranges of 0-5, 5-10, and $10-15^{\circ}C$ for more than 23, 27, and 60 hr with the $K_1$, $K_2$, and $K_3$ slurries, respectively.