• Journal of Korean Society of Industrial and Systems Engineering
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• v.5 no.6
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• pp.1-6
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• 1982

The objective of this thesis to Provide a better insight into the effect of the amount of in-process storage has on the efficiency of production line with variable operation times. It is assumed that the material enters the line at the first work station and is then processed progressively through the line until it exits at the last work station, a finite amount of in-process storage is provided before all but the first work station of the line and the operation time of the work stations are statistically independent and follow exponential distribution. Under the above assumption, optimum allocation model is developed and following two approaches are used : 1) Given the available storage capacity, optimum allocation which minimizes the number of items in the line. 2) Given the available storage capacity, optimum allocation which. maximizes the utilization factor of the line. In a balanced three stage line, the production line efficiency is maximized under both categories when the second in-process storage is larger than the first.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4127-4130
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• 2012

We report a fast, efficient, and facile route for the synthesis of 2,5-dihydro-5-imino-2-methylfuran-3,4-dicarboxylate derivatives from the isocyanide, dialkyl acetylenedicarboxylate and acetic anhydride under ultrasound-assisted conditions. Utilization of easy reaction conditions, very high to excellent yields, and short reaction times makes this manipulation potentially very useful.

• Journal of Korean Institute of Industrial Engineers
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• v.27 no.2
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• pp.169-175
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• 2001

Most of studies on automated storage/retrieval (AS/R) system assumed that storage capacity is given, although it is a very important decision variable in the design phase. We propose a simple algorithm to estimate the required storage capacity, i.e., number of aisles and number of openings in vertical and horizontal directions in each aisle, of an AS/R system under stochastic demand, in which storage requests occur endogenously and exogenously while the retrieval requests occur endogenously from the machines. Two design criteria, maximum permissible overflow probability and maximum allowable storage/retrieval (S/R) machine utilization, are used to compute the storage capacity. This model can be effectively used in the design phase of new AS/R systems.

• Journal of Information Processing Systems
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• v.10 no.4
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• pp.568-580
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• 2014

To enhance the utilization of the traffic channels of a network (instead of allocating radio channel to an individual user), a channel or a group of channels are allocated to a user group. The idea behind this is the statistical distribution of traffic arrival rates and the service time for an individual user or a group of users. In this paper, we derive the blocking probability and throughput of a subscriber station of Worldwide Interoperability for Microwave Access (WiMAX) by considering both the connection level and packet-level traffic under a complete partition scheme. The main contribution of the paper is to incorporate the traffic shaping scheme onto the incoming turbulent traffic. Hence, we have also analyzed the impact of the drain rate of the buffer on the blocking probability and throughput.

• Korean Chemical Engineering Research
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• v.62 no.4
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• pp.364-370
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• 2024

In response to the threats of global warming and climate change, the development of highly energy-efficient lean methane oxidation processes has become crucial. One promising technology is ozone-induced lean methane oxidation (O₃-LMO), which utilizes ozone as an oxidant and a transition metal-loaded zeolite as a catalyst. Our previous study demonstrated that the O₃-LMO system, employing a cobalt-exchanged BEA (Co-BEA) catalyst, effectively abates lean methane (500 ppm) at low temperatures below 200℃ under dry conditions. In this study, we investigated the effect of water vapors on the performance of Co-BEA-based O₃-LMO system. The results indicated that CH₄ conversion, CO₂ selectivity, and O₃ utilization efficiency of the system were not significantly affected by water vapors. Additionally, any temporary suppression of activity could be easily reversed through simple vacuum drying of the catalyst. The system maintained robust activity for over 18 hours during prolonged testing under wet conditions.

• Journal of Hydrogen and New Energy
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• v.25 no.3
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• pp.271-279
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• 2014

A 25kW-class polymer electrolyte membrane (PEM) fuel cell system has been developed for the propulsion of a leisure boat. The fuel cell system was designed to satisfy various performance requirements, such as resistance to shock, stability under rolling and pitching oscillations, and durability under salinity condition, for its marine applications. Then, the major components including a 30kW-class PEM fuel cell stack, a DC-DC converter, a seawater cooling system, secondary battery packs, and balance of plants were developed for the fuel cell system. The PEM fuel cell stack employs a unique design structure called an anodic cascade-type stack design in which the anodic cells are divided into several blocks to maximize the fuel utilization without hydrogen recirculation devices. The performance evaluation results showed that the stack generated a maximum power of 31.0kW while maintaining a higher fuel utilization of 99.5% and an electrical efficiency of 56.1%. Combining the 30-kW stack with other components, the 25kW-class fuel cell system boat was fabricated for a leisure. As a result of testing, the fuel cell system reached an electrical efficiency of 48.0% at the maximum power of 25.6kW with stable operability. In the near future, two PEM fuel cell systems will be installed in a 20-m long leisure boat to supply electrical power up to 50kW for propelling the boat and for powering the auxiliary equipments.

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.2
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• pp.265-271
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• 1994

The effect of soybean meal and barley supplementation of the utilization of rice straw was investigated. Balance trials were conducted with three Japanese Corriedale wethers fed rice straw supplemented with soybean meal and barley at three different levels of protein: low (40 g CP/d, LCP), medium (67 g/d, MCP) and high (94 g/d, HCP). In addition, all the supplements were formulated to contain the same amount of TDN (275 g/d). Voluntary intake of rice straw was not affected by any supplementation, while digestibility of organic matter in sheep given HCO diet was significantly higher (p<0.05) than those on LCP diet. Crude protein, neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibilities of MCP and HCP diets were significantly improved (p<0.05) over the LCP diet. Average daily gain of the animals under MCP and HCP diets were significantly higher (p<0.05) than those under LCP diet. Differences of rumen pH among the treatments were not significant, while concentration of rumen $NH_3-N$ was significantly higher (p<0.05) for HCP diet than for LCP and MCP diets. Total volatile fatty acids ($VFA_s$) and blood urea nitrogen (BUN) concentrations were significantly higher (p<0.05) in sheep fed MCP and HCP diets than those fed LCP diet, while plasma total protein concentration was not affected by any supplementation. Sheep fed MCP diet had a higher nitrogen retention than those fed LCP and HCP diets. It was concluded that rice straw was utilized better by sheep when SBM and barley were supplemented at the medium level of protein.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.4
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• pp.225-231
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• 1988

As the studies on effective utilization of polyunsaturated lipids in sardine (Sardinops melanosticta), the conditions of deacidification, decoloring, and deodorization for processing of refined sardine oil were investigated In the process of refining, phosphoric acid treatment was not effective in removing phosphatides, and optimal condition to neutralize the crude sardine ill was treating for 30min at $40^{\circ}C$. with $0.5\%$ excess of 3M NaOH solution. Decoloring was optimized by adding $5\%$ bleaching earth and treating for 20min at $50^{\circ}C$ under vacuum, and deodorizing was done by steam destillation at $180^{\circ}C$ under 3 torr of vacuum. When deodorizing temperature exceeded $200^{\circ}C$, some changes occured in fatty acid composition and artifacts were appeared on GLC chromatogram.

• Journal of Information Processing Systems
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• v.15 no.3
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• pp.464-477
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• 2019

With the sustained and rapid development of new energy sources, the demand for electric energy is increasing day by day. However, China's energy distribution is not balanced, and the construction of transmission lines is in a serious lag behind the improvement of generating capacity. So there is an urgent need to increase the utilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowable operating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the static thermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique can improve the utilization of transmission capacity to a certain extent. In this paper, the meteorological parameters affecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation of overhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-year actual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under given confidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing the relevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basis for the wind power grid integration and grid intelligence. The results show that the thermal load potential of transmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving the absorptive capacity of power grid.

• Smart Structures and Systems
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• v.23 no.5
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• pp.495-506
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• 2019

This paper presents the results of axial pressure testing on reinforced concrete columns (RCCs) filled with confined normal concrete (NC) and high-strength concrete (HSC) using glass-fiber reinforced plastic pipes (GRP) casing as well as fiber reinforced polymer (FRP). This study aims to evaluate the behavior and mechanical properties of columns confined with GRP casing and FRP wrapping under pressure loads. The major parameters in the experiments were the type of concrete, the effect of GRP casing and FRP wrapping, as well as the number of FRP layers. 12 cylindrical RCCs (150*600) mm were prepared and divided into two groups, NC and HSC, and each group was divided into two parts. In each part, one column was without FRP strengthening layer, a column was wrapped with one FRP layer and another column with two FRP layers. All columns were tested under concentrated compression load. The results of the study showed that the utilization of FRP wrapping and GRP casing improved compression capacity and ductility of RCCs. The addition of one and two layers-FRP wrapping increased compression capacity in the NC group to an average of 18.5% and 26.5% and to an average of 10.2% and 24.8% in the HSC group. Meanwhile, the utilization of GRP casing increased the compression capacity of the columns by 4 times in the NC group and 3.38 times in the HSC group. The results indicated that although both FRP wrapping and GRP casing result in confinement, the GRP casing resulted in increased compression capacity and ductility of the RCCs due to higher confinement. Furthermore, the confinement effect was higher on columns made with NC.