• Geomechanics and Engineering
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• v.34 no.2
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• pp.197-208
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• 2023

Rate-dependent mechanical response of sand, subjected to loading of medium to high strain rate range, is of interest for several civilian and military applications. Such rate-dependent response can vary significantly based on the initial density state of the sand, applied confining pressure, considered strain rate range, drainage condition and sand morphology. A numerical study has been carried out employing a recently proposed visco-plastic constitutive model to explore the rate-dependent mechanical behaviour of Toyoura sand under drained triaxial loading condition. The model parameters have been calibrated using the experimental data on Toyoura sand available in published literature. Under strain rates higher than a reference strain rate, the simulation results are found to be in good agreement with the experimentally observed characteristic shearing behaviour of sand, which includes increased shear strength, pronounced post-peak softening and suppressed compression. The rate-dependent response, subjected to intermediate strain rate range, has further been assessed in terms of enhancement of peak shear strength and peak friction angle over varying initial density and confining pressure. The simulation results indicate that the rate-induced strength increase is highest for the dense state and such strength enhancements remain nearly independent of the applied confinement level.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.862-868
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• 2012

Based on the recently derived general expression for the rates of diffusion-controlled reactions, we calculate the rates of dismutation of the superoxide anion radical catalyzed by Cu/Zn superoxide dismutases (SOD). This is the first attempt to calculate the absolute rates of diffusion-controlled enzyme reactions based on the atomiclevel molecular dynamics simulations. All solvent molecules are included explicitly and the effects of the structural flexibility of enzyme, especially those of side chain motions near the active site, are included in the present calculation. In addition, the actual mobility of the substrate molecule is taken into account, which may change as the molecule approaches the active site of enzyme from the bulk solution. The absolute value of the rate constant for the wild type SOD reaction obtained from MD simulation is shown to be in good agreement with the experimental value. The calculated reactivity of a mutant SOD is also in agreement with the experimental result.

• Journal of radiological science and technology
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• v.19 no.2
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• pp.71-77
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• 1996

Studies were conducted to determine the clinical application of photodiode. We compared photodiode with ion-chamber as to change of tube potential, tube current, mAs and measured decreasing rate of penetration dose. When tube potential was changed from 60 kVp to 120 kVp, output of photodiode and ion-chamber were changed from 0.4 to 1.625, and 1.018 to 4.268, respectively. This was a good agreement to theory that $I=Kv^2it$(I is intensity, K is constant, v is tube potential, i is tube current, t is time). Characteristics for change of tube current and mAs were also a good agreement to theory. And comparison in decreasing rate of penetration dose was similar except above 6 cm in depth. Our results indicated that photodiode was a good instrument for relative measurement of radiation exposure, but we can not use the photodiode for absolute radiation dose.

• The Journal of Fisheries Business Administration
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• v.38 no.1 s.73
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• pp.1-17
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• 2007

This study is aimed at investigating optimum level of payments in the direct payment program for aquaculture extruded pellets both theoretically and practically by analyzing the effects on production and income in accordance with Green Box conditions of WTO Agreement on Agriculture. In particular, by analyzing both effects on production and income, it evaluates and compares payments affecting to the level of production and income, respectively. Analysis results indicate that the optimum level of payments in the direct payment program for aquaculture extruded pellets is determined by the growth rate of farmed fish, farming period, price and volume of extruded pellets, and additional amount of cost increase and decrease. Suppose that growth rates of farmed fish by extruded pellets(EP) and raw fish - based moist pellets(MP) are the same, it reveals the optimum level of payment should be lowered from the current level of payment. However, when the growth rate of farmed fish by EP is lower than that by MP, the optimum level of payment should be raised from the current level and total amount of payments by area should be increased as well.

• Journal of ILASS-Korea
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• v.16 no.2
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• pp.69-75
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• 2011

This article presents computational fluid dynamics (CFD) simulations of sub-micron particle movements and flow characteristics in laboratory-scale electrostatic precipitator (ESP) without corona discharge, and for simulation, it uses the commercial CFD program (CFD-ACE) including electrostatic theory and Lagrangian-based equation for sub-micron particle movement. For validation of CFD results, a simple cylindrical type of ESP is simulated and numerical prediction shows fairly good agreement with the analytical solution. In particular, the present study investigates the effect of particle diameter, inlet flow rate, and applied electric potential on particle collection efficiency and compares the numerical prediction with the experimental data, showing good agreement. It is found that the particle collection efficiency decreases with increasing inlet flow rate because the particle detention time becomes shorter, whereas it decreases with the increase in sub-micron particle diameter and with the decrease of applied electric voltage resulting from smaller terminal electrostatic velocity.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.1
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• pp.137-151
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• 1988

Thurbulent thermal convection between two plates, bottom plate is at higher temperature $T_{h}$ and the upper plate is at lower temperature $T_{i}$ is numerically investigated. Model equations are abridged Reynolds stress equations; full Reynolds stress equations are simplified to yield algebraic relations in case of mean square velocity fluctuations in vertical and horizontal directions. Boundary conditions for turbulent kinetic energy k and mean square temperature variance .thera.$^{2}$oner bar at the plate surfaces are set to be zero and those of dissipation rate of turbulent kinetic energy .epsilon. and dissipation rate of mean square temperature variance .epsilon.$_{\theta}$ are assumed at first grid point nearest to the boundary surfaces, whose values are approximated by inviscid estimates. Results show that temperature profiles are in good agreement with experimental data except transition region, in which temperature is over-predicted. Such discrepancy becomes larger as the Rayleigh number becomes smaller. Nusselt numbers, which are calculated from the temperature gradients at the boundary surfaces, are also in good agreement with experimental data.a.a.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.1
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• pp.262-267
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• 2006

We verified the reproducibility of constitution by IGM and the agreement rate between sasang constitution by QSCCII and constitution by IGM. We analyzed the results of 64 subject who were judged as identical sasang constitution by repeated QSCC II. First, we compared the two results of constitutions by IGM hat peformed by one O.M.D(Oriental Medicine Doctor) at an interval of one year. Second, we examined hypothesis established by one O.M.D, that is about relation of constitutions by IGM and QSCCII, such as I type-Taeeumin, II type-Soyangin and III type-Soeumin in constitutions. There were no statistical significances in reproducibility of constitution by IGM. Although there was a tendency of relevance of sasang constitution by QSCC II with constitution by IGM, there was no statistical significance. Hypothesis that is established by clinical experiences must be verified by an effective statistical method. And there is a necessity to complement the method including mechanical measurements about constitution classification which are performed by a diagnosis relying on individual intuition.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.3
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• pp.177-183
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• 2016

The purpose of this study was to evaluate the reliabilities of questions and diagnostic value of the Korean Sasang Constitutional Diagnostic Questionnaire(KS-15). The young adults aged 20's participated in this study. The first survey was conducted in march, 2016, and the second one was conducted two weeks later. Three hundred and three questionnaires and the informed consent were obtained from all participants. The test-retest kappa analysis was used to identify the reliabilities of the questions and diagnostic value, and the significance level was .05. The number of subjects was 303 [87(28.7%)males and 216(71.3%)females]. The Cronbach's α were .630 in 6 characteristic questions. The test-retest reliabilities of questions were ranged from .469 to 734. The agreement rate of KS-15 between the first and second constitutional diagnostic value was 87.13%(Kappa=0.794). The higher Sasang constitutional probability score in first survey resulted in the higher agreement rate between first and second diagnostic value. KS-15 seems to be a reliable implement. Further studies for the reliability of the people of different ages and suitable cut off point in Sasang constitutional probability score are needed for the practical use of KS-15.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.58-63
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• 2010

In this paper, we proposed a wearable respiration measurement system with textile capacitive pressure sensor. Belt typed textile capacitive pressure sensor approach of respiration measurement, from which respiration signatures and rates can be derived in real-time for long-term monitoring, are presented. Belt typed textile capacitive pressure sensor has been developed for this measurement system. the distance change of two plates by the pressure of motion has been used for the respiration measurement in chest area. Respiration rates measured with the textile capacitive pressure sensor was compared with standard techniques on 8 human subjects. Accurate measurement of respiration rate with developed sensor system is shown. The data from the method comparison study is used to confirm theoretical estimates of change in capacitance by the distance change. The current version of respiratory rate detection system using textile capacitive pressure sensor can successfully measure respiration rate. It showed upper limit agreement of $3.7997{\times}10^{-7}$ RPM, and lower limit of agreement of $-3.8428{\times}10^{-7}$ RPM in Bland-Altman plot. From all subject, high correlation were shown(p<0.0001). The proposed measurement method could be used to monitor unconscious persons, avoiding the need to apply electrodes to the directly skin or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using textile capacitive pressure sensor offers a promising possibility of convenient measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range and quality of the rate-finding, broadening the potential application areas of this technology.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.3
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• pp.220-228
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• 2008

In this study the aerodynamic characteristics of a canard-controlled missile with freely spinning tailfins were investigated by using a semi-empirical method and a CFD code. The mean aerodynamic coefficients for the rolling and roll damping moments were first calculated and then used to predict the roll-rate of freely spinning tailfins. The calculation of roll-rate in the CFD code was carried out by combining a Chimera overset grid system and 6-DOF analysis module. The predicted roll-rate was in good agreement with the experimental data for the roll and yaw canard control inputs. It was also shown that the results are in good agreement with the prediction by a CFD code. This indicates that the semi-empirical method can be used to predict the roll-rate of a canard-controlled missile with freely spinning tailfins.