• Food Science of Animal Resources
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• v.22 no.2
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• pp.130-136
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• 2002

Four kinds of polyphosphate solution(0. 1.5, 3.0 and 4.5%) were injected by 10% into pork loin such that polyphosphate could be added by 0% (water, control), 0.15%, 0.30% and 0.45%, respectively. Then, the effect of adding polyphosphate to pork loin was investigated after it was refrigerated at 4$\^{C}$ for 2 days and boiled until its internal temperature became 75$\^{C}$ and 80$\^{C}$. The pork loin that was boiled with polyphosphate added showed better water holding capacity, texture, and sensory juiciness than control group, but it produced lower pork flavor and strong abnormal flavor. As the internal temperature became higher, the pork loin showed higher cooking loss, worse tenderness and juiciness, and better pork flavor. This study demonstrates that the water holding capacity and palatability of boiled pork loin can be improved by the addition of about 0.15-0.30 g of polyphosphate per 100 g of meat.

• International Journal of Fluid Machinery and Systems
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• v.3 no.4
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• pp.315-323
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• 2010

This work investigates the influence of water compressibility on pressure pulsations induced by rotor-stator interaction (RSI) in hydraulic machinery, using the commercial CFD solver ANSYS-CFX. A pipe flow example with harmonic velocity excitation at the inlet plane is simulated using different grid densities and time step sizes. Results are compared with a validated code for hydraulic networks (SIMSEN). Subsequently, the solution procedure is applied to a simplified 2.5-dimensional pump-turbine configuration in prototype with different speeds of sound as well as in model scale with an adapted speed of sound. Pressure fluctuations are compared with numerical and experimental data based on prototype scale. The good agreement indicates that the scaling of acoustic effects with an adapted speed of sound works well. With respect to pressure fluctuation amplitudes along the centerline of runner channels, incompressible solutions exhibit a linear decrease while compressible solutions exhibit sinusoidal distributions with maximum values at half the channel length, coinciding with analytical solutions of one-dimensional acoustics. Furthermore, in compressible simulation the amplification of pressure fluctuations is observed from the inlet of stay vane channels to the spiral case wall. Finally, the procedure is applied to a three-dimensional pump configuration in model scale with adapted speed of sound. Normalized Pressure fluctuations are compared with results from prototype measurements. Compared to incompressible computations, compressible simulations provide similar pressure fluctuations in vaneless space, but pressure fluctuations in spiral case and penstock may be much higher.

• Journal of the Korean Society for Heat Treatment
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• v.29 no.5
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• pp.220-226
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• 2016

The mechanical properties of Ti-6Al-4V can be improved by microstructural control through the heat treatment in ${\alpha}+{\beta}$ region. The heat treatment was carried out with a variety of heat treatment temperatures and holding times to find the optimized heat treatment conditions and it was analyzed by linking the microstructural characteristics and mechanical properties. The part of ${\beta}$ phase with $10{\pm}2wt%$ vanadium was transformed into ${\alpha}^{{\prime}{\prime}}$ martensite phase after quenched, so the hardness and tensile properties were decreased below $900^{\circ}C$. The higher the heat treatment temperature is, the smaller is the vanadium-rich region, which leads to transformation into hcp ${\alpha}^{\prime}$ martensite above $900^{\circ}C$. The hardness and tensile properties were improved due to the hard ${\alpha}^{\prime}$ martensite. As the holding times were longer, the hardness and tensile properties decreased below $900^{\circ}C$ because of the softening effect by the grain growth. When varying the holding times above $900^{\circ}C$, the change of mechanical properties was slight because the softening effect of grain growth and the strengthening effect of ${\alpha}^{\prime}$ phase were counteractive. Therefore, the best conditions of heat treatment, which is in the range of $920{\sim}960^{\circ}C$, 40 min, WQ, can effectively improve the mechanical properties of Ti-6Al-4V.

• Journal of the Korean Society of Safety
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• v.13 no.4
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• pp.240-247
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• 1998

This paper proposed a method for solving the nonlinear integer programing problem to get easily the best compromise solution while holding a nonlinear property by using the genetic algorithms. Also, this paper reported that the optimization problem of systems reliability as was solved by using the preposed method, and the numerical comparison experiments between the 0-1 LP/0-1 NP formulations were demonstrated, and from the quantitative evaluation the efficiency of the proposed method was demonstrated.

• Journal of the Korean Operations Research and Management Science Society
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• v.18 no.1
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• pp.1-18
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• 1993

The family disaggregation model of hierarchical production planning (HPP) is the problem of (0 -1) mixed integer programming that minimizes the total sum of setup costs and inventory holding costs over the planning horizon. This problem is hard in a practical sense since optimal solution algorithms have failed to solve it within reasonable computation times. Thus effective familoy disaggregation algorithm should be developed for HPP. The family disaggregation algorithm developed in this paper consists of the first stage of finding initial solutions and the second stage of improving initial solutions. Some experimental results are given to verify the effectiveness of developed disaggregation algorithm.

• CDE review
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• v.21 no.2
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• pp.50-60
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• 2015

Corresponding to the high consumption rate of the selfie stick for cell phone camera, the design of the product is becoming diverse. However, relatively low cost selfie stick models are not strong enough to stand the weight of the cell phone. This results into a bending of the stick or the accidental fall of the cell phone by the failure of the holding unit. As a solution to the problem, design of selfie stick that is structurally strong enough to stand the weight of the cell phone with the minimum weight for the portability is proposed in this paper.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.65
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• pp.11-22
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• 2001

Recently, many studies on the supply chain management have been published due to increasing attention placed on the design and performance analysis of the supply chain as a whole. Using the Beer distribution game introduced in Sterman[1995], we develop a simple order-up-to-R inventory model to minimize sum of the inventory holding cost and shortage cost under probabilistic demand. We show that performance of the model is robust through extensive simulation experiment. Applying the model to serially connected supply chain, we observe that, if the unit shortage cost is relatively high, R value computed independently is an optimal solution.

• Industrial Engineering and Management Systems
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• v.6 no.2
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• pp.136-145
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• 2007

The selection of suppliers and the determination of order quantities to be placed with those suppliers are important decisions in a supply chain. In this research, a non-linear mixed integer programming model is presented to select suppliers and determine the order quantities. The model considers the purchasing cost which takes into account quantity discount, the cost of transportation, the fixed cost for establishing suppliers, the cost for holding inventory, and the cost of receiving poor quality parts. The capacity constraints for suppliers, quality and lead-time requirements for the parts are also taken into account in the model. Since the purchasing cost, which is a decreasing step function of order quantities, introduces discontinuities to the non-linear objective function, it is not easy to employ traditional optimization methods. Thus, a heuristic algorithm, called particle swarm optimization (PSO), is used to find the (near) optimal solution. However, PSO usually generates initial solutions randomly. To improve the PSO solution quality, a heuristic procedure is proposed to find an initial solution based on the average unit cost including transportation, purchasing, inventory, and poor quality part cost. The results show that PSO with the proposed initial solution heuristic provides better solutions than those with PSO algorithm only.

• Journal of Korea Foundry Society
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• v.37 no.1
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• pp.14-20
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• 2017

The microstructure, electrical conductivity and hardness variation of an AZ91-5wt%Sn Mg alloy sample during a solid-solution and aging heat treatment were instigated by optical microscopy, scanning electron microscopy, X-ray diffraction and by Rockwell hardness techniques in this study. The XRD result shows that the main phases in the as-casted alloy are ${\alpha}$-Mg, $Mg_{17}Al_{12}$ and $Mg_2Sn$. From the SEM images of the AZ91-5wt%Sn Mg alloy after the solution treatment, the $Mg_{17}Al_{12}$ phases in the alloy were found to have dissolved into the matrix with an increase in the holding time during the solution treatment, but $Mg_2Sn$ phases were clearly observable. The highest peak hardness of the AZ91-5wt%Sn Mg alloy is 82HRE at an aging temperature of $200^{\circ}C$.

• Food Science of Animal Resources
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• v.31 no.4
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• pp.497-505
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• 2011

The objective of this study was to examine the effect of hot-boning and soy sauce as a curing agent on the processing properties of beef jerky. Beef jerky was prepared under the following four treatment conditions; Beef jerky with cold-boned beef and salt solution, beef jerky with cold-boned beef and soy sauce solution, beef jerky with hot-boned beef and salt solution, and beef jerky with hot-boned beef and soy sauce solution. Cured meat and jerky containing hot-boned beef had a significantly higher pH, water holding capacity (WHC), moisture content, Myofibrillar fragmentation index (MFI), processing yields, tenderness, and sensorial scores than samples containing cold-boned beef (p<0.05). Regardless of the raw materials, the jerky containing soy sauce had a significantly lower pH, WHC, moisture content, salt content, TBA, CIE $L^*$ and $b^*-$ values, and significantly higher MFI, mechanical tenderness, and sensorial scores (p<0.05). Based on these findings, we concluded that the use of hot-boned meat and soy sauce was the most effective boning method and curing agent during beef jerky processing.