• Plant Biotechnology Reports
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• v.4 no.2
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• pp.117-123
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• 2010

We used a flow cytometer to investigate the variations in endopolyploidy (the frequencies of nuclei with DNA contents equivalent to 4C through 16C) during the short period of the early growing stage in vigorously growing young tissues of maize seedlings. We examined different portions of the root and leaves that had been growing for 7 (day 7) and 13 (day 13) days after germination. Endoreplication showed two opposing phenomena without aging. In one case, the endopolyploidy of the first leaf was higher on day 13 than on day 7. In the latter case, endopolyploidy decreased, as clearly revealed by a comparison of the endopolyploidy of the second leaves and the 160-170 mm portion of the seminal root on days 7 and 13. Endopolyploidy was also lower in the top of the leaf. In roots, endopolyploidy was increased by the exogenous application of abscisic acid for only 1 day. The levels of endopolyploidy increased without an increase in cell size in the roots. These results showed that endoreplication occurs in actively growing and young tissue and that the variation can be induced in the short period examined.

• Journal of the Korean Institute of Gas
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• v.9 no.4 s.29
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• pp.44-49
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• 2005

In this study, a process safety evaluation is implemented, in which the process hazards are investigated systematically about hydrogen production plants. Be used qualitative Safety management method such as HAZOP and FMEA. Were analysed potential hazards (human errors or operating failures of every processing steps) about parameters that flow, pressure, temperature of hydrogen production plants through HAZOP that making deviations applied signified guide words. Analysed to using FMEA mainly about bad components or troubles that equipments breakdown and malfunction in facilities and then propose its influences, and counterproposal.

• Journal of Korean Institute of Industrial Engineers
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• v.19 no.2
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• pp.23-34
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• 1993

Although there are numerous studies that address the problem of optimal machine grouping and part family classification for cellular manufacturing, little research has been reported that studies the conditions where cellular manufacturing is appropriate. This paper, in order to evaluate and compare the job shop with the GT cellular shop, the performance of those shops were simulated by using SIMAN. We tested the effect of independent variables including changes of product demands, intercell flow level, group setup time, processing time variability, variety of material handling systems, and job properties (ratio of processing time and material handling time). And also performance measures (dependent variables), such as machine utilization, mean flow time, average waiting time, and throughput rate, are discussed. Job shop model and GT cellular shop written in SIMAN simulation language were used in this study. These systems have sixteen machines which are aggregated as five machine stations using the macro feature of SIMAN. The results of this research help to better understand the effect of production factors on the performance of cellular manufacturing systems and to identify some of the necessary conditions required to make these systems perform better than traditional job shops. Therefore, this research represents one more step towards the characterization of shops which may benefit from cellular manufacturing.

• The KSFM Journal of Fluid Machinery
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• v.14 no.6
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• pp.61-67
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• 2011

The study is to analyze the chemical and heat-flow reactions in the hydrogen generation unit(autothermal reformer), using computational numerical tools. Autothermal reformer(ATR) is involved in complex chemical reaction, mass and heat transfer due to exothermic and endothermic reactions. Therefore it is necessary to reveal the effects of various operation parameters and geometries on the ATR performance by using numerical analysis. Numerical analysis needs to dominant chemical reactions that includes Full Combustion(FC) reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction and Direct Steam Reforming(DSR) reaction. The objective of the study is to improve theoretically the reformer design capability for the goal of high hydrogen production in the autothermal reformer using methane. Hydrogen production reached maximum in a certain value of Oxygen to Carbon Ratio(OCR) or Steam to Carbon Ratio(SCR). When the longitudinal distance to dimeter ratio(L/D) is increased, hydrogen production increases.

• Journal of the Korean Operations Research and Management Science Society
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• v.27 no.4
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• pp.41-65
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• 2002

We study a multi-component production/inventory system in which individual components are made to meet various demand types. We assume that the demands arrive according to a Poisson process, but there is a fixed probability that a demand requests a particular kit of different components. Each component is produced by a flow line with several stations in which the processing times of each station follow a two-stage Coxian distribution. The production of each component is operated by an independent base-stock policy with blocking. We assume that the time needed to assemble final products follows a general distribution and the capacity of an assembling facility is sufficiently large. The objective of this study is to obtain key performance measures such as the distribution of the number of each orders for each final product and the mean time of fulfilling a customer order. The basic principle of the proposed approximation method is to decompose the original system into a set of subsystems, each subsystem being associated with a flow line. Each subsystem is analyzed in isolation using a Marie's method. An iterative procedure is then used to determine the unknown parameters of each subsystem. Numerical results show that the accuracy of the approximation method is acceptable.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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• pp.199-207
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• 1998

Ginseng saponin (G5) purified from Panax ginseng, increase renal blood flow in rats. Nitric oxide (NO) is thought to be a substance endogenously released by G5 in preconstricted lungs and cultured endothelial cells. The present study aims to determine whether G5 could stimulate endogenous 1'elease of NO in rat kidney and urine levels of the stable NO metabolites, nitrite (NO,) and nitrate (NO,) and urinary COMP levels were measured 8 hr after a single intraperitoneal injection of GS (200 mg/kg) Into rats. The effects of the WO synthesis inhibitor, Nu-nitro-L-arginine methyl ester, .1nd the NO precursor, L-arginine, on the G5-induced changes were also determined. The activity of NO synthase, as determined by conversion of ('"C)-L-arginine to ('"C)-L-citrulline, in whole kidney, glomeruli and cortical tubules were also investigated. A single injection of GS resulted in endogenous production of NO as reflected by increase in serum and urine levels of N021N03 and urinary cGMP levels, which were inhibited by the addition o ( N-nitro-L-arginine methyl ester and restored fly L-arginine. GS also stimulated the activity of NO synthase in whole kidney as well as glomeruli and cortical tubules, and Nu-nitro-L-arginine methyl tilter significantly prevented this increase. In conclusion, GS stimulates endogenous NO production and thus, may play a protective role 1 11 the kidney by modulating renal blood flow.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.6
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• pp.550-560
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• 2000

In order to minimize compression power and analyze the cause of exergy loss for a dry ice production cycle with 3-stage compression, the variation of compression power was investigated and the exergy analysis was peformed for the cycle. In this cycle, $CO_2$, is used both as a refrigerant and as a raw material for dry ice. The behavior of compression power and irreversibility in the cycle were examined as a function of intermediate pressure. From this result, the conditions for the minimum compression power were obtained in terms of the first stage or the third stage pressure. In addition, the irreversibilities for the cycle were investigated with respect to the efficiency of compressor. Result shows that the optimum pressure is not consistent with the conventional pressure obtained from the equal-pressure-ratio assumption. This is mainly due to the change in mass flow rate of the intermediate stage compressor by the flash gas evaporation from the flash drums. Most important is that the present exergy analysis enabled us to find bad performance components for the cycle and informed us of methods to improve the cycle performance.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.937-944
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• 2022

Electric vehicles (EVs) have been growing to reduce energy consumption and greenhouse gas (GHG) emissions in the transportation sector. The increasing number of EVs requires adequate recharging infrastructure, and at the same time, adopts low- or zero-emission electricity production because the GHG emissions are highly dependent on primary sources of electricity production. Although previous research has studied solar photovoltaic (PV) -integrated EV charging stations, it is challenging to optimize spatial areas between where the charging stations are required and where the renewable energy sources (i.e., solar photovoltaic (PV)) are accessible. Therefore, the primary objective of this research is to support decisions of siting EV charging stations using a spatial data clustering method integrated with Geographic Information System (GIS). This research explores spatial relationships of PV power outputs (i.e., supply) and traffic flow (i.e., demand) and tests a community in the state of Indiana, USA for optimal sitting of EV charging stations. Under the assumption that EV charging stations should be placed where the potential electricity production and traffic flow are high to match supply and demand, this research identified three areas for installing EV charging stations powered by rooftop PV in the study area. The proposed strategies will drive the transition of existing energy infrastructure into decentralized power systems. This research will ultimately contribute to enhancing economic efficiency and environmental sustainability by enabling significant reductions in electricity distribution loss and GHG emissions driven by transportation energy.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.4
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• pp.395-406
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• 2020

The objectives of this study were to develop the optimal structures of recirculating aquaculture tank for improving the removal efficiency of solid materials and maintaining water quality conditions. Flow analysis was performed using the CFD (computational fluid dynamics) method to understand the hydrodynamic characteristics of the circular tank according to the angle of inclination in the tank bottom (0°, 1.5° and 3°), circulating water inflow method (underwater, horizontal nozzle, vertical nozzle and combination nozzle) and the number of inlets. As the angle in tank bottom increased, the vortex inside the tank decreased, resulting in a constant flow. In the case of the vertical nozzle type, the eddy flow in the tank was greatly improved. The vertical nozzle type showed excellent flow such as constant flow velocity distribution and uniform streamline. The combination nozzle type also showed an internal spiral flow, but the vortex reduction effect was less than the vertical nozzle type. As the number of inlets in the tank increased, problems such as speed reduction were compensated, resulting in uniform fluid flow.

• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.4
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• pp.113-119
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• 2001

Ammonia emissions during composting of hog manure mixed with sawdust were studied in four runs comprising a total of 22 pilot-scale reactor vessels. These four runs extended previous work and both verified and extended the previous conclusions. The pilot-scale vessels were 205 L insulated stainless steel drums that were aerated either continuously (high/low thermostatically controlled fans) or intermittently (5 min high fan 55 min off). Temperature ammonia emissions air flow rates carbon dioxide production and oxygen utilization moisture and dry matter reduction initial and final chemical compositions were measured. Ammonia emissions from the intermittently aerated vessels were only about 50% as great as those from the continuously aerated ones but this was found to be a result more related to total air flow than to aeration technique. All of the data for total result more related to total air flow were fitted with a linear regression line y=0.139x+29.835 where y is ammonia expressed as g of N and x is air flow in kg with $R^2$=0.6808. this general trend indicates that about 50% reduction in ammonia emissions can be achieved with 75% reduction in air flow. For the aeration techniques used the minimum oxygen level in te exhaust gas from the vessels was 5% and this is probably a resonable lower limit constraining air flow reduction. However within this constraint lower air flow now appears to be a technique that can reduce odorous ammonia emissions.