• Nuclear Engineering and Technology
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• v.23 no.4
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• pp.387-400
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• 1991

An ocean compartment model simulating transport of nuclides by advection due to ocean circulation and intertaction with suspended sediments is developed, by which concentration breakthrough curves of nuclides can be calculated as a function of time. Dividing ocean into arbitrary number of characteristic compartments and performing a balance of mass of nuclides in each ocean compartment, the governing equation for the concentration in the ocean is obtained and a solution by the numerical integration is obtained. The integration method is specially useful for general stiff systems. For transfer coefficients describing advective transport between adjacent compartments by ocean circulation, the ocean turnover time is calculated by a two-dimensional numerical ocean model. To exemplify the compartment model, a reference case calculation for breakthrough curves of three nuclides in low-level radioactive wastes, Tc-99, Cs-137, and Pu-238 released from hypothetical repository under the seabed is carried out with five ocean compartments. Sensitivity analysis studies for some parameters to the concentration breakthrough curves are also made, which indicates that parameters such as ocean turnover time and ocean water volume of compartments have an important effect on the breakthrough curves.

• Smart Structures and Systems
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• v.19 no.1
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• pp.39-46
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• 2017

Finite element model updating is very effective procedure to determine the uncertainty parameters in structural model and minimize the differences between experimentally and numerically identified dynamic characteristics. This procedure can be practiced with manual and automatic model updating procedures. The manual model updating involves manual changes of geometry and analyses parameters by trial and error, guided by engineering judgement. Besides, the automated updating is performed by constructing a series of loops based on optimization procedures. This paper addresses the ambient vibration based finite element model updating of long span reinforced concrete highway bridges using manual model updating procedure. Birecik Highway Bridge located on the $81^{st}km$ of Şanliurfa-Gaziantep state highway over Firat River in Turkey is selected as a case study. The structural carrier system of the bridge consists of two main parts: Arch and Beam Compartments. In this part of the paper, the arch compartment is investigated. Three dimensional finite element model of the arch compartment of the bridge is constructed using SAP2000 software to determine the dynamic characteristics, numerically. Operational Modal Analysis method is used to extract dynamic characteristics using Enhanced Frequency Domain Decomposition method. Numerically and experimentally identified dynamic characteristics are compared with each other and finite element model of the arch compartment of the bridge is updated manually by changing some uncertain parameters such as section properties, damages, boundary conditions and material properties to reduce the difference between the results. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of long span highway bridges. Maximum differences between the natural frequencies are reduced averagely from %49.1 to %0.6 by model updating. Also, a good harmony is found between mode shapes after finite element model updating.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.186-191
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• 2004

Sorption kinetics of 2-chlorophenol(2-ChP), 2,4-dichlorophenol(2,4-DChP) and 2,4,5-trichlorophenol (2,4,5-TChP), onto montmorillonite modified with hexadecyltrimethyl ammonium cations(HDTMA-mont) were investigated. One-site mass transfer model(OSMTM) and two compartment first-order kinetic model(TCFOKM) were used to analyze kinetics. As expected from the number of model parameters involved, the three-parameter TCFOKM was better than the two-parameter OSMTM in describing sorption and desorption kinetics of chlorophenols in HDTMA-mont. For all chlorophenols, the results of OSMTM analysis indicate that the predominant deprotonated speciation(at pH 9.15) exhibited higher mass transfer coefficient( $k_{s}$ ) than the protonated speciation(at pH 4.85). This is because the deprotonated speciation has stronger hydrophobic interaction than protonated speciation. Most sorption completes in three hours. The fraction of the fast sorption and the first-order sorption rate constants for the fast and slow compartments in TCFOKM were determined by fitting experimental data to the TCFOKM. The results of kinetics reveal that the fraction of the fast sorption( $f_1$) and the sorption rate constants in the fast compartments( $k_1$) were in the order 2,4,5-TChP > 2,4-DChP > 2-ChP, which agrees with the magnitude of the $K_{ow}$ . The first-order sorption rate constants in the fast compartment(10$^{0.8}$ - 10$^{1.22}$ h $r^{-1}$ ) were much larger than those in the slow compartment(10$^{-1}$.74/ - 10$^{-2}$.622/ h $r^{-1}$ ).> ).).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.17 no.1
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• pp.64-80
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• 1991

The SKINTEX Method is based on a two-compartment physico-chemical model which includes a Biomembrane Barrier in compartment one and an organized macromolecular matrix in compartment two. Test samples absorb onto or permeate through the keratin/collagen Biomembrane Barrier and then can interact with the organized macromolecular matrix. Changes in the integrity of the barrier release a dye indicator: Changes in the matrix can alter its transparency. The sum of these two responses is read spectrophotometrically at 470nm. An early investigation of 950 chemicals and formulations in the SKINTEX System produced results which were 89% concordance to in vivo Draize dermal irritation results obtained with 24-hour occluded application of test samples with-out abrasion and standard scoring. Alkaline materials were analyzed in a specialized SKINTEX AMA Protocol. In this early study, the model did not distinguish nonirritant test materials and formulation with PDII(Primary Dermal Irritation Index)in the range from 0 to 1.2, A High Sensitivity Assay Protocol(HSA)was developed to amplify the changes in both compartments of this model and provide more accurate calibration of these changes. A study of 60 low irritation test samples including cosmetics, household products, chemicals and petro-chemicals distinguished nonirritants with PDII $\leq$ 0.7 for 26 of 30 nonirritants. A second protocol was developed to evaluate the SKINTEX model predictability with respect to human irritation. The Human Response Assay (HRA )has been optimized based on differences in penetration and irritation responses in humans and rabbits. An additional 32 test materials with different mechanisms and degrees of dermal toxicity were evaluated by the HRA. These in vitro results were 86% concordant to human patch test results. In order to further evaluate this model, a Standard Chemical Labelling (SCL) Protocol was developed to optimize this system to predict Draize dermal irritation results after a 4-hour application of the test material. In a study of 52 chemicals including acids, bases, solvents, salts, surfactants and preservatives, the SCL results demonstrated 85% concordance to Draize results for a 4-hour application of test samples on non-abraded rabbit skin. The SKINTEX System, including three specialized protocols, provided results which demonstrated good correlation to the endpoint of dermal irritation in man and rabbits at different application times.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.495-500
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• 1997

For hydrogen management in severe accidents with degraded nuclear core of PWR's, several experiments have been performed in the SNU hydrogen mixing facility. The objectives are understanding the extent of hydrogen mixing and analyzing the effects of factors which dominate uniform or non-uniform mixing at compartments in the containment building. The facility represents on a 1/11th linearly scaled model of the YGN unit 3&4, hydrogen was simulated by helium. Because there are the gaps between safety injection tank and compartment layers in the containment, the test facility was constructed in three dimentinal mode for analyzing of mixture behavior through the gaps. From the experimental results we could conclude that overall hydrogen concentration distributed uniformly in the free volume of the test compartment, but fluctuated in the gaps. This paper is focused on experimental result from several experiment.

• Korean Journal of Ecology and Environment
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• v.36 no.3 s.104
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• pp.295-303
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• 2003

Sorption kinetics of hydrophobic organic compounds (chlorobenzene and phenanthrene) in natural wetland soils was investigated using laboratory batch adsorbers. One -site mass transfer model (OSMTM) and two compartment first-order kinetic model (TCFOKM) were used to analyze sorption kinetics. Analysis of OSMTM reveals that apparent sorption equilibria were obtained within 10 to 75 hours for chlorobenzene and 2 hours for phenanthrene, respectively. For chlorobenzene, the sorption equilibrium time for surface soil was longer than that of deeper soil presumably due to physico-chemical differences between the soils. For phenanthrene, however, no difference in sorption equilibrium time was observed between the soils. As expected from the number of model parameters involved, the three-parameter TCFOKM was better than the two-parameter OSMTM in describing sorption kinetics, The fraction of fast sorption ($f_1$) and the first-order sorption rate constants for fast ($k_1$)and slow ($k_2$) compartments were determined by fitting experimental data to the TCFOKM. The results of TCFOKM analysis indicate that the sorption rate constant in the fast compartment($k_1$) was much greater than that of slow fraction($k_2$) . The fraction of the fast sorption ($f_1$) and the sorption rate constant in the fast compartment($k_1$) were increasing in the order of increasing $k_{ow}$, phenanthrene > chlorobenzene. The first-order sorption rate constants in the fast ($k_1$) and slow ($k_2$) compartments were found to vary from $10^{-0.1}\;to\;-10^{1.0}$ and from $10^{-4}\;to-10^{-2}$, respectively.

• Korean Journal of Radiology
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• v.22 no.1
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• pp.139-154
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• 2021

Magnetic resonance imaging (MRI) has become a crucial tool for evaluating mediastinal masses considering that several lesions that appear indeterminate on computed tomography and radiography can be differentiated on MRI. Using a three-compartment model to localize the mass and employing a basic knowledge of MRI, radiologists can easily diagnose mediastinal masses. Here, we review the use of MRI in evaluating mediastinal masses and present the images of various mediastinal masses categorized using the International Thymic Malignancy Interest Group's three-compartment classification system. These masses include thymic hyperplasia, thymic cyst, pericardial cyst, thymoma, mediastinal hemangioma, lymphoma, mature teratoma, bronchogenic cyst, esophageal duplication cyst, mediastinal thyroid carcinoma originating from ectopic thyroid tissue, mediastinal liposarcoma, mediastinal pancreatic pseudocyst, neurogenic tumor, meningocele, and plasmacytoma.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.48-53
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• 1995

This study investigates a simple mathematical model for the quantitative estimation of regional myocardial blood flow in experimental canine coronary artery thrombosis using Rb-82 dynamic myocardial positron emission tomography. The coronary thrombosis was induced using the new catheter technique by narrowing the lumen of coronary vessel gradually, which finally led to partial obstruction of coronary artery. Ten Rb-82 dynamic myocardial PET scans were performed sequentially for each experiment using our 5, 10 and 20 second acquisition protocol, respectively, and three regions of interest were drawn on the transaxial slices, one on left ventricular chamber for input function and the other two on normal and decreased perfusion segments for the flow estimation in those regions. Single compartment model has been applied to the measured sets of regional PET data, and the rate constants of influx to myocardial tissue were calculated for regional myocardial flow estimates with the three parameter fits of raw data by the Levenberg-Marquardt method. The results showed that, (1) single compartment model suggested by Kety-Schmidt could be used for the simple estimation of regional myocardial blood flow, (2) the calculated regional myocardial blood flow estimates were dependent on the selection of input function, which reflected partial volume effect and left ventricular wall motion, and (3) mathematically fitted input and tissue time activity curves were more suitable than the direct application of the measured data in terms of convergence.

• Current Optics and Photonics
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• v.1 no.5
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• pp.529-537
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• 2017

We explored how changes in blood vessel compliance affected the systolic rise time (SRT) of the maximum blood pressure (BP) peak wave and the diastolic fall time (DFT) of the minimal BP peak wave, compared to photoplethysmograpic (PPG) parameters, using a two-compartment, second-order, arterial Windkessel model. We employed earlier two-compartment Windkessel models and the components thereof to construct equivalent blood vessel circuits, and reproduced BP waveforms using PSpice technology. The SRT and DFT values were obtained via circuit simulation, considering variations in compliance (the dominant influence on blood vessel parameters attributable to BP changes). And then performed regression analysis to identify how compliance affected the SRT and DFT. We compared the SRTs and DFTs of BP waves to the PPG values by reference to BP changes in each subject. We confirmed that the time-shift propensities of BP waves and the PPG data were highly consistent. However, the time shifts differed significantly among subjects. These simulation and experimental results allowed us to construct an initial trend curve of individual BP peak time (measured via wrist PPG evaluations at three arm positions) that facilitated accurate individual BP estimations.

• Journal of Radiation Protection and Research
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• v.9 no.2
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• pp.76-89
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• 1984

Weighted committed dose equivalents($W_T\;H_{50}$) per intake of unit activity of four nuclides-I-131, I-133, Cs-134 and Cs-137-, which was based on the concepts of ICRP Pub. 30, are calculated for adult who is 70 kg and 25 years old and, for infant who is 10 kg and 1 year old. Metabolism of iodine taken through oral or inhalation pathway is described by using the three-compartment model which consists of inorganic, thyroid and organic compartment. After intake, the amount of iodine in every compartment is calculated by solving the transfer equations among the these compartments. As soon as caesium is taken into the body, it is distributed uniformly in the body through the transfer compartment. In this case, the amount of caesium in total body is calculated by using the total body compartment model which is divided into two tissue compartments because of their different biological half-lifes of caesium in body. As a result of calculations, whether oral or inhalation pathway, the values of ($W_T\;H_{50}$) per intake of unit activity of I-131 for infants are about ten times as much as those of adults. On the other hand, for Cs-134 and Cs-137, the values of $W_T\;H_{50}$ per intake of unit activity show that, whether adults of infants, they have almost the same values.