• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.113-122
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• 2002

Beef loins that retailed in market were used as experimental samples. Some beef samples in raw state were packaged with PVDC as aerobic and vacuum condition. The other beef samples were cooked until core temperature arrived at 70$^{\circ}C$ and then packaged immediately in the same way of raw samples. After these samples were irradiated by electron beam 6kGy, irradiated samples were stored in refrigerator(2～4$^{\circ}C$). Identify and quantity of cholesterol oxides were analysed stored at 0 and 7 days, respectively. During the early stage of storage, 7$\beta$-hydroxycholesterol and 7-ketocholesterol were respectively produced from the raw meat samples, and the production of these chemicals were significantly higher (P$<$0.05) from the meats with aerobic packaging than those with vacuum packaging. With the passage of storage time, 7$\alpha$-hydroxycholesterol, 20$\alpha$-hydroxycholesterol, $\beta$-epoxide, $\beta$-epoxide and some other chemicals, which were not produced during the early stage of storage, were produced, Also, the production of these chemicals were significantly increased (P$<$0.05) with the passage of storage time. Cooked meat after irradiation and irradiated meat after cooking produced cholesterol on the 7th day of storage, although this chemical was not produced during the early stage of storage. Production of cholesterol oxides was significantly increased (P$<$0.05) with the passage of storage time for all treatments, and showed significantly lower value (P$<$0.05) with the vacuum packaging than aerobic packaging. Summarizing the aforementioned results, it was found that the production of cholesterol oxides was more easily affected by packaging condition than irradiation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.309-316
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• 2020

Waterway design should prioritize appropriate channel width to ensure preferential safe passage for the arrival and departure of vessels. To calculate the minimum channel width required for safe passage a comprehensive review of several factors is required. These factors include vessel maneuverability, determined by vessel size, type and speed; environmental factors such as wind, tide, and wave action; human factors, including personal experience and operator judgment as well as marine traffic and navigation support facilities for decision making. However, the Korean channel width design standard is based only on vessel length, and requires improvement when compared with the standards of PIANC, USA, and Japan. This study aims to estimate the appropriate channel width required for one-way traffic in a straight channel, considering various vessel and environmental factors, using Fast Time Simulation (FTS). When the wind speed is 25 knots, with a current speed of 2 knots and a normal vessel speed of 10 knots FTS shows that a 150K GT Cruise Ship requires a minimum channel width of 0.67-0.91 the vessel length (L), whereas a 120K TEU Container Ship and a 300K DWT VLCC require 0.79-1.17 and 1.02-1.59, respectively. Such results can be used to calculate the minimum channel width required for safe passage as an improved Korean design standard.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1183-1196
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• 2018

Objective: This study ascertained effects of roughage quality, period of day at meal termination and time lapse after feeding on digesta load in the rumen. Methods: Veld hay was untreated (poor roughage quality, PRQ), improved (improved roughage quality, IRQ) by treating with urea or semi-improved by spraying with urea (semi-improved roughage quality, SIRQ). Experiment 1a used four rumen fistulated sheep to determine in-sacco degradability. Twelve sheep ($56.3{\pm}4.59kg$) were blocked by weight and randomly allocated to IRQ (n = 6) and PRQ (n = 6) to determine solid and liquid passage rates. In experiment 1b, nine sheep ($37.6{\pm}9.34kg$) were blocked by weight and randomly allocated to IRQ (n = 4) and PRQ (n = 5) to determine digestibility. Sixteen sheep ($36.47{\pm}9.46kg$) were blocked by body weight and randomly allocated to IRQ (n = 8) and PRQ (n = 8). Two sheep were slaughtered for each sampling time in each treatment (IRQ and PRQ) at 0, 6, 12, and 24 h after feeding to determine rumen load. In experiment 2, eighteen goats ($25.4{\pm}9.08kg$) were blocked by weight and randomly allocated to IRQ (n = 6), SIRQ (n = 6), and PRQ (n = 6). Then all 18 goats were slaughtered soon after meal termination in the morning; afternoon and evening to determine the effect of period of day on rumen fill. Results: Rate of degradation and effective degradability were enhanced by improvement of roughage quality. Roughage quality had no effect on digestibility, but digestibility was higher in goats than sheep. Fractional passage rate of particles was higher for IRQ than PRQ, but similar for liquids. Digesta fractional clearance rates at 24 h after feeding were 0.018/h (IRQ) and 0.006/h (PRQ). Period of day had an influence on rumen load. Neutral detergent fibre load for goats were above 2.03 kg/100 kg body weight for all diet treatments. Conclusion: Following starvation, passage rate had negligible effects on emptying of rumen load.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.9
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• pp.825-834
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• 2000

A heat exchanger analysis is performed to investigate the heating characteristics of cryogenic nitrogen by ambient air for the purpose of cryogenic automotive propulsion. The heat exchanger is a concentric triple-passage for supercritical nitrogen, and the radial fins are attached on the outermost tube for the crossflow of ambient air. The temperature distribution is calculated for the nitrogen along the passage, including the real gas properties of nitrogen, the fluid convections and the conductions through the tube walls and the fins. Since the wall temperature of the outer (ambient side) tube is very low in most cases, a heavy frost can be formed on the surface, affecting the heat exchange performance. By the method of the similarity between the heat and the mass transfer of moist air, the frost growth and the time-dependent effectiveness of the heat exchanger are calculated for various operating conditions. It is concluded that the frost formation can augment the heating of nitrogen during the initial period because of the latent heat, then gradually degrades the heat exchange because of the increased thermal resistance. Practical design issues are discussed for the flow rate of nitrogen, the velocity and humidity of ambient air, and the sizes of the fin.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.270-278
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• 2017

This paper describes development procedure and verification test results of a bi-propellant thruster using hydrogen peroxide and kerosene. The design thrust of the thruster is about 500 N and six swirl type coaxial injectors were used. The passage type manifolds were employed for the injector head to reduce the response time. The passage was designed to minimize stagnation points and recirculation region to ensure uniform flow distribution and sufficient cooling performance through flow analysis using Fluent. A catalytic igniter using hydrogen peroxide was installed at the center of the injector head. The propellant feeding and spray characteristics were confirmed by hydraulic tests. Combustion tests were performed on design and off-design points to analyze combustion characteristics under various mixture ratio conditions. The combustion test results show that combustion efficiency was over 95 % and chamber pressure fluctuation were less than 1.5 % under all test conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.13-17
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• 2006

Almost every day close passage or near miss events happens in south part of Istanbul Strait between the vessel runs in the local area and pass strait transit. The vessels run in the local area pass close bow or aft of transit vessel or come close and wait for transit vessel because of inexperienced or incompetent skipper or because of time limitation or failure in technical equipment or lack of technical equipment or old equipment. This close passages create profound dangers for the surroundings. By the this research has been aimed to point out mentioned dangers by the concrete as number. For this purpose has been utilized JMS Ship Handling Simulator which has been settled in ITU Maritime Faculty and Environmental Stress Model which has been built up and improved in Inoue Laboratory. Has been put in the senarios which been played during simulation implementations transferred to the numerical risk occured during passage of South Part of Istanbul Strait by the Environmental Stress Model . Thus so, the riskwhich Istanbul Strait face everyday has been expressed as numerical and concrete.

• Ocean Science Journal
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• v.43 no.1
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• pp.61-65
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• 2008

Feeding apparatus, mechanism and passage of ingested prey were described for Nemopilema nomurai (Scyphozoa: Rhizostomeae). N. nomurai medusae without central mouths have developed complicated canal systems connecting the tip of the tentacle and oral arm to the gut cavity. The number of junctions in the canal system increases with the bell diameter. The prey is gathered by paralyzing nematocyst at the tentacles and by adhering cirri at the oral arms and scapulets. They are engulfed into the terminal pore located at the oral arms and scapulets, and entered into the gut cavity via the canal system. The estimated digestion time is 1 hour and 20 min. The diameter of terminal pore is always about 1 mm, implying that they could not eat prey larger than that pore size. On the other hand, ephyrae have central mouths and could swallow prey as large as adults could. Exploitation of the same size of food by adult and ephyra implies that N. nomurai can affect seriously the whole food web, massively ingesting micro- and mesozooplankton and cutting the energy transfer toward the higher level of carnivores.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.11
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• pp.1518-1526
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• 2001

In this paper, the mechanism of unsteady potential interaction and wake interaction in one stage axial turbine is numerically investigated at design point in two-dimensional viewpoint. The numerical technique used is the upwind scheme of Van-Leer's Flux Vector Splitting (FVS) and Cubic spline interpolation is applied on zonal interface between stator and rotor. The inviscid analysis is used to embody the influence of potential interaction only and viscous analysis is used to embody the influences of both potential interaction and wake interaction at the same time. The potential-flow disturbance from the stator into a rotor passage and the periodic blockage effect of rotor produce the unsteady pressure on the blade surface in inviscid analysis. After the wake is cut by rotor, two counterrotating votical patterns flanking the wake centerline in the passage are generated. So, these phenomena magnify the unsteady pressure in viscous analysis than that in inviscid analysis. The resulting unsteady forces on the rotor, generated by the combined interaction of the two effects by potential and wake interaction, are discussed.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.5
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• pp.696-704
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• 2009

In this paper, the flow characteristics through an industrial safety relief valve used to protect the crankcase room in a large-sized marine engine have been numerically investigated using the moving-mesh strategy. With the room pressure higher than the cracking one, the spring-loaded disc becomes open and then the air in the room blows off into the atmosphere, resulting in the reduction of the room pressure and then the shutoff of the disc. Numerical simulations are performed on the compressible air flow through the relief valve (${\phi}160mm$) with the initial room pressure (0.11 bar or 0.12bar) higher than the cracking one (0.1 bar). The numerical method has been validated by comparing the results with the empirical ones. Results show that the disc motion and flow characteristics can be successfully simulated using the moving-mesh strategy and depend strongly on the spring stiffness and the flow passage shape. With increasing spring stiffness, the maximum disc displacement decreases and thus the total disc-opening time also decreases. In addition, the flow passage shape makes a significant effect on the velocity and direction of the flow.

• Journal of Environmental Impact Assessment
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• v.20 no.2
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• pp.133-140
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• 2011

A numerical study with Envi-met model is experimented to investigate the characteristics of wind pattern in Gangwon innovation city. In all case, most conditions such as wind speed, temperature, and surface are considered as the same, but wind direction is the only different factor. The wind directions considered in this study have a meaning of prevailing wind direction. When the prevailing wind with the direction of $247^{\circ}$ blows into the city, the ventilation passage toward the outside of city is formed and the stagnation of air is not expressed. In case of having the direction of $270^{\circ}$, most evident ventilation passages are composed. When the inflow wind direction is the north, $0^{\circ}$, there is some possibility of stagnation phenomenon. The case where the representative wind direction of three kind will flow with development, in compliance with the building is caused by with screening effect of some and shows a true stagnation phenomenon, wishes in the park and flowing water and the greens area to be for a long time formed and the wind direction is maintained.