• Journal of the Korean Applied Science and Technology
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• v.26 no.2
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• pp.179-185
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• 2009

The esterification of the reactants of Jatropha oil and methanol added by propyleneglycol was done using p-TSA catalyst. And then the emulsification of triglyceride and methanol was conduced by 1.0vol% GMS. The emulsified reactants were transesterified at $65^{\circ}C$ using TMAH and mixed catalyst (50wt%-TMAH+50wt%-NaOH) respectively. The esterification conversion at the 1:8 molar ratio of free fatty acid to methanol using 8.0wt% p-TSA was 94.7% within 80min. The overall conversion at the 1:8 molar ratio of mixed fat(50wt% Beef Tallow) to methanol and $65^{\circ}C$ using mixed catalyst was 95.4% The cloud point of Biodiesel decreased with the addition of petroleum diesel.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.48
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• pp.299-310
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• 1998

Actually mixed assembly line is mixed with open and close type workstation. This workstation is called hybridworkstation. The propose of this paper is to determine the sequencing of model that minimize line length for actual(hybridworkstation) mixed model assembly line. we developed three mathematical formulation of the problem to minimize the overall length of a line with hybrid station. Mathematical formulation classified model by operato schedule. Mixed model assembly line is combination program and NP-hard program. Thus computation time is often a critical factor in choosing a method of determining the sequence. This study suggests a tabu search technique which can provide a near optimal solution in real time and use the hill climbing heuristic method for selecting initial solution. Modified tabu search method is compared with MIP(Mixed Integer Program). Numerical results are reported to demonstrate the efficiency of the method.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.3
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• pp.163-168
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• 2000

The problems of mixed $H_2/H_{\infty}$ filtering design fer continuous and discrete time linear systems with time delay are investigated. The main purpose is to design a stable mixed $H_2/H_{\infty}$ filter which minimizes the H$_2$Performance measure satisfying a prescribed H$_{\infty}$ norm bound on the closed loop system in continuous-time case and discrete-time case, respectively. The sufficient conditions of existence of filter, the mixed $H_2/H_{\infty}$ filter design method, and the upper bound of performance measure are proposed by LMI(linear matrix inequality) techniques in terms of all finding variables. Also, we present optimization problems in order to get the optimal mixed $H_2/H_{\infty}$ filter in continuous and discrete time case, respectively.

• The Korean Journal of Ecology
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• v.26 no.6
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• pp.335-340
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• 2003

Patterns of mass loss and nutrient release from decomposing oak (Quercus mongolica) and mixed litters (Q. mongolica, Betula schmidtii, Acer pseudo-sieboldianum, Kalopanx pictus and Tilia amurensis) in a natural hardwood forest in Gyebangsan (Mt.) were examined using litterbags placed on the forest floor for 869 days. Mass loss rates from decomposing litter were consistently higher in mixed litter (59%) than in oak litter types (52%) during the study period. Nutrient concentrations such as nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) from decomposing litter were also higher in mixed litter than in oak litter types. Nutrient concentrations (N, P, Ca, and Mg) increased compared with initial concentration of litter, while K concentrations dropped rapidly at the first 5 months and then stabilized. The results suggest that mas loss and nutrient release obtained from decomposing litter of single species in mixed hardwood forest ecosystem should be applied with caution because of the potential differences of mass loss and nutrient release between single litter and mixed litter types.

• KSBB Journal
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• v.13 no.1
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• pp.20-25
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• 1998

Optimum conditions of the cellulose-hydrolysis reaction with mixed enzymes(cellulase extracted from Penicellium funiculosum mixed with $\beta$-glucosidase extracted from Almod) were investigated to increase the production of glucose from cellulose. Experimental result showed that optimum conditions fro pH, activity ratio of $\beta$-glucosidase to cellulase, concentration of mixed enzymes, concentration of cellulose as a substrate, and temperature range were 4.2, 0.4, 0.8, U/mL, 40 g/L, and 37$\pm$3$^\circ C$, respectively. In these conditions, quantities of glucose productions by using mixed enzymes were larger than those by using cellulase at optimum conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.291-292
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• 2008

This study used EPR's sheet and cable as a specimen, and measured residual voltage depending on the induced voltage, thickness of the sheet, and shape of the sheet and cable. The results of the study lead to the following conclusion: 1) The residual voltage increased in proportion to the induced voltage as time increases; 2) The residual voltage of the basic mixed specimen and practical mixed specimen increased as time increased; 3) The peak of the cable appeared earlier than that of the sheet in both of the basic mixed specimen and practical mixed specimen.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.110-115
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• 2000

The mean streamline analysis using the empirical loss correlations has been developed for performance prediction of industrial mixed-flow fan impellers in the present study. New simple, but effective, models for the additional Euler input work characteristic and an internal recirculation loss due to internal flow reversal under the low flowrate conditions are proposed in this paper. Comparison of overall performance predictions with six sets of test data of mixed-flow fans is accomplished to demonstrate the accuracy of the proposed models. Predicted performance curves by the present set of loss models agree fairly well with experimental data for a variety of mixed-flow fan impellers over the entire operating conditions. The prediction method presented herein can be used efficiently in the conceptual design phase of mixed-flow fan impellers.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.119-124
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• 2003

In this study, retardation behavior of fatigue crack under single overloading of the mixed mode I+II state was experimentally investigated. To produce single overload in the mixed mode I+II state, the compact tension shear (CTS) specimen and loading device were used. The propagation tests for fatigue crack were performed under mode I loading overloading afterwards. We examined the observed deformation aspects, variation of fatigue life and crack propagation rate, and the aspects of retardation behavior from tests. The retardation effect of mixed-mode single overload on fatigue crack propagation behavior was smaller than that of mode I single overload. It has been confirmed that the retardation behavior did not immediately appear and the retardation length was short when the component of mixed-mode overload was changed.

• Fashion & Textile Research Journal
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• v.8 no.5
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• pp.591-596
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• 2006

In order to analyze the tailorbility of different fabrics for men's suit, FAST system has been used for measuring the distribution of mechanical properties in this study. As results, cashmere mixed woolen fabrics showed the minimum degree in relaxation shrinkage, formability, and shear rigidity than any other fabrics, and also showed more than 6% as maximum level of extensibility. Thus, cashmere mixed woolen fabrics requires careful tailoring in lay-out, marking, and cutting. It is necessary to establish new tailoring criteria for automatic sewing with cashmere mixed woolen fabrics than any other fabrics, because they show more failure rate of tailorbility. There have been noticeably more variation of shrinkage and extension for woolen fabrics with cashmere mixed than 100% woolen fabrics by evaluating the formability of the suits when these are completed to suits through cutting and tailoring from fabrics. Especially nylon mixed woolen fabrics showed shrinkage overall, but polyester mixed woolen fabrics showed extension at waist area. Thus, it is necessary to adjust the appropriate overfeed rate considering the amount of shrinkage and extension while tailoring.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.481-484
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• 2000

Practical structures are subject not only to tension but also to shear and torsional loading. Even under uniaxial loading, when the load is not perpendicular to the crack plane, mixed mode crack can occur. Hence, it is necessary to evaluate the fatigue behavior under mixed mode loading. In this study, the propagation behavior of the fatigue crack of the STS304 steels under mixed mode loading condition was investigated. The mode I and II stress intensity factors of CTS specimen were calculated using elastic finite element method with experimental results. The fatigue crack propagation under mixed mode was evaluated by the effective stress intensity factor proposed by Tanaka.