• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.3
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• pp.248-257
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• 2016

Recently, researches on the free-piston Stirling engines(FPSEs) are actively investigated. FPSEs have merits in its light weight, simple structure, and little need for maintenance, thus becoming a promising solution for the power conversion of renewable energy and waste heat recycle. This paper presents the methodology that estimates damping coefficients using analytical models of linear and nonlinear dynamics for FPSEs, and validates the methodology by comparing with existing experimental results. The analysis model predicts an operable range of linear damping coefficients forming limit cycles by using the root locus, and time responses obtained by numerical integration determines nonlinear damping coefficients. The model predictions are compared with experimental results of the well-known FPSE B-10B. We also investigate the damping characteristics regarding heater temperatures and power piston motions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.3
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• pp.326-335
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• 1998

In this study, a steady three-dimensional incompressible turbulent flow within a torque converter was numerically analyzed with the introduction of interrow mixing model. Mixing planes were introduced to exchange the flow informations between two adjacent elements of the torque converter. The mixing planes were installed among three elements of the torque converter. Therefore, in the present method, it could be possible to calculate the flow-filed within the torque converter without any assumption of circulating flow rates or any extension of boundaries toward the upstream and the downstream for each element. The numerically calculated performances of the torque converter were in good agreement with experimental results, and the complex flow patterns were be observed according to design and off-design condition. As a conclusion, it was found that the present numerical method was very effective in the steady flow analysis of torque converters.

• Korean Journal of Remote Sensing
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• v.24 no.1
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• pp.25-33
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• 2008

To investigate the hydrologic impacts of climate changes on dam inflow for Soyanggangdam watershed $(2694.4km^2)$ of northeastern South Korea, SLURP (Semi-distributed Land Use-based Runoff Process) model and the climate change results of CCCma CGCM2 based on SRES A2 and B2 were adopted. By the CA-Markov technique, future land use changes were estimated using the three land cover maps (1985, 1990, 2000) classified by Landsat TM satellite images. NDVI values for 2050 and 2100 land uses were estimated from the relationship of NDVI-Temperature linear regression derived from the observed data (1998-2002). Before the assessment, the SLURP model was calibrated and verified using 4 years (1998-2001) dam inflow data with the Nash-Sutcliffe efficiencies of 0.61 to 0.77. In case of A2 scenario, the dam inflows of 2050 and 2100 decreased 49.7 % and 25.0 % comparing with the dam inflow of 2000, and in case of B2 scenario, the dam inflows of 2050 and 2100 decreased 45.3 % and 53.0 %, respectively. The results showed that the impact of land use change covered 2.3 % to 4.9 % for the dam inflow change.

• Earthquakes and Structures
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• v.22 no.3
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• pp.231-243
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• 2022

Beam-column joints (BCJs) are recognized among the most crucial zones in reinforced concrete structures, as they are the critical elements subjected to a complex state of forces during a severe earthquake. Under such conditions, BCJs exhibit behaviors with impacts that extend to the whole structure and significantly influence its ductility and capability of dissipating energy. The focus of this paper is to investigate the effect of undamaged transverse beam (secondary beams) on the ductility of concrete BCJs reinforced with conventional steel and shape memory alloys bars using pushover analysis at tip of beam under different axial load levels at the column using a nonlinear finite element model in ABAQUS environment. A numerical model of a BCJ was constructed and the analysis outcomes were verified by comparing them to those obtained from previous experiments found in the literature. The comparison evidenced the capability of the calibrated model to predict the load capacity response of the joint. Results proved the ability of undamaged secondary beams to provide a noticeable improvement to the ductility of reinforced concrete joints, with a very negligible loss in load capacity. However, the effect of secondary beams can become less significant if the beams are damaged due to seismic effects. In addition, the axial load was found to significantly enhance the performance of BCJs, where the increase in axial load magnified the capacity of the joint. However, higher values of axial load resulted in greater initial stiffness of the BCJ.

• IMMUNE NETWORK
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• v.21 no.3
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• pp.22.1-22.17
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• 2021

Chitinase-3-like-1 (CHI3L1) is known to induce inflammation in the progression of allergic diseases. Previous our studies revealed that 2-({3-[2-(1-cyclohexen-1-yl)ethyl]-6,7-dimethoxy-4-oxo-3,4-dihydro-2-quinazolinyl}sulfanyl)-N-(4-ethylphenyl)butanamide (K284-6111; K284), the CHI3L1 inhibiting compound, has the anti-inflammatory effect on neuroinflammation. In this study, we investigated that K284 treatment could inhibit the development of atopic dermatitis (AD). To identify the effect of K284, we used phthalic anhydride (5% PA)-induced AD animal model and in vitro reconstructed human skin model. We analyzed the expression of AD-related cytokine mediators and NF-κB signaling by Western blotting, ELISA and quantitative real-time PCR. Histological analysis showed that K284 treatment suppressed PA-induced epidermal thickening and infiltration of mast cells. K284 treatment also reduced PA-induced release of inflammatory cytokines. In addition, K284 treatment inhibited the expression of NF-κB activity in PA-treated skin tissues and TNF-α and IFN-γ-treated HaCaT cells. Protein-association network analysis indicated that CHI3L1 is associated with lactoferrin (LTF). LTF was elevated in PA-treated skin tissues and TNF-α and IFN-γ-induced HaCaT cells. However, this expression was reduced by K284 treatment. Knockdown of LTF decreased the expression of inflammatory cytokines in TNF-α and IFN-γ-induced HaCaT cells. Moreover, anti-LTF antibody treatment alleviated AD development in PA-induced AD model. Our data demonstrate that CHI3L1 targeting K284 reduces AD-like skin inflammation and K284 could be a promising therapeutic agent for AD by inhibition of LTF expression.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.405-412
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• 2016

Infestation of adults and pupae of sweetpotato whitefly, Bemisia tabaci, on paprika (Capsicum annuum var. angulosum) grown in greenhouses in Jinju, Gyeongnam province during 2014was determined by counts of the number of target stage of B. tabaci per leaflet. Binomial sampling plans were developed based on the relationship between the mean density per leaflet (m) and the proportion of leaflets infested with less than T whiteflies ($P_T$), according to the empirical model $(({\ln}(m)={\alpha}+{\beta}({\ln}(-{\ln}(1-P_T))))$. T was defined as the tally threshold, and set to 1, 2, 3, 4, 5 (adults) and 1, 3, 5, 7 (pupae) per leaflet in this study. Increasing the sample size, regardless of tally threshold, had little effect on the precision of the binomial sampling plan. Based on the precision of the model, T = 1 was chosen as the best tally threshold for estimating densities of B. tabaci adults and T = 3 was best tally threshold in B. tabaci pupae. Using the results obtained in the greenhouse, a simulated validation of the developed sampling plan by RVSP (Resampling Validation for Sampling Plan) demonstrated the plan's validity. Above all, the binomial model with T = 1 and T = 3 provided reliable predictions of the mean densities of B. tabaci adults and pupae on greenhouse paprika.

• Fashion & Textile Research Journal
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• v.3 no.5
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• pp.415-422
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• 2001

Focusing on working with fashion show as fashion model in South Korea, this study was develop a fashion model typology based on specific model characteristics related demographics and body, job satisfaction/dissatisfaction factors. The survey was done through questionnaire and 194 fashion models were used in the data analysis. The statistical analysis used in this study were frequency, ${\chi}^2$-test, cluster Analysis, MANOVA. ANOVA and Duncan multiple range test. The results of this study were as follows: 1) The majority of sample were as follows: unmarried, college graduate and undergraduate, resident in the Seoul, 20 to 24 yrs old female with 175-177 cm, 52-54 kg, B-W-H (33-24-35 inch). 2) The types of fashion model were classified into 4 types: showing type, lack of professionalism type, matured professionalism type, dissatisfaction with job-environment type. The model segments were profiled on levels of various job related attitude factors, job satisfaction/dissatisfaction, model education, working condition, human relation, regulation discrimination, fashion show stage level, the job of model, body & clothing, and promising job. 3) There were significant differences found between their sex, academic background, guarantee, and in all factors in their job related attitude factors, job satisfaction/dissatisfaction, model education, working condition, human relation, regulation discrimination, fashion show stage level, the job of model, body & clothing, style promising job.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3B
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• pp.231-237
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• 2009

This study presents a numerical model to simulate density currents developing two dimensionally. The ${\kappa}-{\varepsilon}$ model is used for the turbulence closure. Elliptic flow equations are solved by the finite volume method. In order to investigate the applicability of the numerical model, discontinuous density currents are simulated numerically. The vortices due to the instability at the interface are simulated, showing a good agreement with the experimental visualizations in the literature. It is also investigated that the transition from slumping phase to inertial phase occurs when a bore generated at the end wall overtakes the front. However, the propagation of the density current is retarded compared with the experimental results. Two-dimensional modeling seems to have an effect on underestimating the front velocity of the density current.

• Korean Journal of Food Science and Technology
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• v.37 no.5
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• pp.850-855
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• 2005

Model was developed to predict the growth of Listeria monocytogenes in raw pork. Experiment condition for model development was full 5-by-7 factorial arrangements of temperature (0, 5, 10, 15, and $20^{\circ}C$) and time (0, 1, 2, 3, 18, 48, and 120 hr). Gompertz values A, C, B, and M, and growth kinetics, exponential growth rate (EGR), generation time (GT), lag phase duration (LPD), and maximum population density (MPD) were calculated based on growth increased data. GT and LPD values gradually decreased, whereas EGR value gradually increased with increasing temperature. Response surface analysis (RSA) was carried out using Gompertz B and M values, to formulate equation with temperature being main control factor. This equation was applied to Gompertz equation. Experimental and predictive values for GT, LPD, and EGR, compared using the model, showed no significant differences (p<0.01). Proposed model could be used to predict growth of microorganisms for exposure assessment of MRA, thereby allowing more informed decision-making on potential regulatory actions of microorganisms in raw pork.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.178-182
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• 1998

Previously, we showed that acetone enhanced aryl hydrocarbon hydroxylase (AHH) activity in only 3-methylcholanthrene (MC)- or $\beta$-naphtoflavone (BNF)-inducible microsomes of rat liver. In the present study, the possible mechanism underlying acetone action on AHH was investigated in the liver microsomes from MC-pretreated rats. Other n-alkylketones except acetone did not increase AHH activity, which rather decreased significantly with the length of alkyl side chain. Acetone had no effect on the activity of NADPH-cytochrome P450 reductase or inhibited the formation of 3-OH benzo(a)pyrene (B(a)P) in nonenzymatic model ascorbic acid system. However, in cumene hydroperoxide (CuOOH)-supported B(a)P hydroxylation, acetone enhanced its velocity remarkably by 30% at the optimal concentration (30 $\mu$M CuOOH and 1.0% acetone). From these results, we conclude that acetone may facilitate the formation of an activated oxygen species or the insertion of oxygen into B(a)P molecule in CYP1A rich microsomes.