• Proceedings of the KSME Conference
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• 2001.06d
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• pp.121-126
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• 2001

In this study, reduced-scale experiments were conducted to understand smoke movements in tunnel fires with the natural ventilation. The 1/20 scale experiments were conducted under the Froude scaling since the smoke movement in tunnels is governed by buoyancy force. Six cases of experiments(pool diameter is 6.5cm, 7.3cm, 8.3cm, 10cm, l2.5cm and l5.4cm), in which vertical vents positioned 1m from the fire source symmetrically, were conducted in order to evaluate the effect of the vent on smoke movement. In case of heat release rate under 2MW, smoke front reached to the tunnel exit about 20 see delayed with ventilation and the smoke velocity was proportional to the power of the heat release rate. Temperature after the vent was lower than without vent. In case of l5.4cm pool, the temperature difference was about $50^{\circ}C$. It was confirmed that the thickness of smoke layer was maintained uniformly under the 35% height of tunnel through the visualized smoke flow by a laser sheet and the digital camcoder.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.63-69
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• 2014

Domestic automobile companies have adopted drum type brake system for commercial vehicles. However recently those companies have been applying disc-brake system to solve vehicle control-instability and inefficient heat discharge performance of conventional drum brake system for a medium commercial vehicle. Because the kinetic energy of a running commercial vehicle is relatively high, the brake system should discharge lots of heat energy while braking. A ventilated type brake disc has been used to increase heat discharge performance of a brake system. The vent structure of a disc highly affects cooling efficiency. This paper compares thermal characteristics of three types of vent structure in JASO C421 braking condition. It is found that the slant bend type disc has the lowest temperature and thermal stress distributions in the braking condition.

• Journal of the Korean earth science society
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• v.30 no.4
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• pp.454-463
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• 2009

In this study, from January 2006 to February 2009, we observed 107 ice spikes formed in a natural state, and analyzed their environment. We developed an experimental device to reproduce ice spikes in laboratory and successfully made 531 ice spikes. We analyzed the process of the formation and the principle of how those ice spikes grow through videotaped data of the formation in the experiment. In the natural world, when the surface of water and the lower part of a vessel begin to freeze, a vent (breathing hole) develops at the surface where an ice is not frozen; this vent serves as the seed of an ice spike. It is assumed that the volume expansion of ice in the vessel which occurs when water freezes makes the supercooled water go upward through the vent and becomes an ice bar called an ice spike. In the laboratory, however, when distilled water is poured into an ice tray cube and kept in the experimental device for about one and a half hours at a temperature of -12- $-13^{\circ}C$, a thin layer of ice then begins to develop on the surface of the water, the vent is formed, and ice spikes form for about 10-30 minutes. These spikes stop growing when the end becomes clogged. Ice spikes can be described as falling into seven categories of shape, with the apex type topping the list followed by the slant type in the natural state and the vertical type predominating in the laboratory.

• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1826-1831
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• 2006

A novel hyperthermophilic, anaerobic, heterotrophic archaeon, designated strain $NA1^T$, was isolated from a deep-sea hydrothermal vent area (depth, 1,650 m) within the Papua New Guinea-Australia-Canada-Manus (PACMANUS) field. Cells of this strain were motile by means of polar flagella, coccoid-shaped with a diameter of approximately $0.5-1.0{\mu}m$, and occurred as single cells. Optimal temperature, pH, and NaCl concentration for growth were $80^{\circ}C$, 8.5, and 3.5%, respectively. The new isolate was an obligate heterotroph that utilized yeast extract, beef extract, tryptone, peptone, casein, and starch as carbon and energy sources. Elemental sulfur was required for growth and was reduced to hydrogen sulfide. The G+C content of the genomic DNA was 52.0 mol%. Phylogenetic analysis of the 16S rRNA gene indicated that strain $NA1^T$ belongs to the genus Thermococcus, and the organism is most closely related to T. gorgonarius, T. peptonophilus, and T. celer; however, no significant homology was observed among species by DNA-DNA hybridization. Strain $NA1^T$ therefore represents a novel species for which the name Thermococcus onnurineus sp. novo is proposed. The type strain is $NA1^T$ (=KCTC 10859, =JCM 13517).

• Food Science and Preservation
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• v.4 no.3
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• pp.237-243
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• 1997

Numerous variables affect product cooling rate of pressure cooling system for fruits and vegetables. These include carton vent area, initial and desired final product temperature, flow rate and temperature of the cooling air, product size, shape and thermal properties and product configuration(whether in bulk or packed in shipping cartons). This study was carried out to determine the influence of each of these variables as they affect cooling time. The opening ratio and number of the vent hole were recomended as 4∼10% and 2∼4ea., respectively, for a minimum alt flow resistance and for a uniform air flow pattern. In the cooling experiment for tomatoes and mandarins, optimum air flow rate was 0.04 m3/min.kg in terms of energy saving. The cooling air temperature should be about 2$^{\circ}C$ less than the desired final product temperature for reducing cooling time.

• Natural Product Sciences
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• v.12 no.3
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• pp.153-156
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• 2006

The antisnake venom activity of Clerodendrum viscosum Vent. (Fam. Verbenaceae), a plant traditionally used in India for the treatment of snake bite was evaluated by in vitro and in vivo methods. While in vitro studies were performed using human blood, in vivo studies were carried out using mice administered three different i.p doses of the extract, 5 min before the administration of Naja naja snake venom. The results of the in vitro studies showed that the extract probably interacts with but does not stabilize membrane protein. In the in vivo studies the extract showed significant antisnake venom activity, which may be attributed to its possible interference with the acetylcholine receptor sites. Hence the present investigation justifies the traditional use of Clerodendrum viscosum (C. viscosum) as antisnake venom.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.553-558
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• 2001

The effect of poor feather cover on feed intake and production was examined in two commercial strains of layers (tinted and brown egg) over 91-98 weeks of age. Hens were housed at four per cage ($600cm^2/bird$) in a commercial layer shed which ranged in temperature from 13.2 to $16.8^{\circ}C$. At the start of the experiment 50% of the birds were classified as having poor feather cover. Feather score was highly correlated with feed intake. Poor feather cover on the neck and the back were the best indicators of hens with high feed intake. Feed intake of hens with poor feather cover was 16% higher (p<0.05) than hens with good feather cover. Hens with good feather cover produced more eggs (p<0.05) early in the trial and had a higher (p<0.05) liveweight, but there was no significant differences in egg weight. Feed per dozen eggs was superior (p<0.05) in hens with good feather cover. Feather cover on the back and vent were the best indicators of overall feather score, while the tail, base of tail and vent were the body parts most affected in birds with poor feather cover.

• Korean Journal of Microbiology
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• v.48 no.1
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• pp.42-47
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• 2012

Hydrothermal vents (HTV) provide special environments for evolution of lives independent on solar energy. HTV samples were gained from Tofua arc trench in Tonga, South Pacific. We investigated archaeal diversity enriched using combinations of various electron donors (yeast extract and $H_2$) and electron acceptors [Iron (III), elemental sulfur ($S^0$) and nitrate. PCR amplification was performed to detect archaeal 16S rRNA genes after the cultures were incubated $65^{\circ}C$ and $80^{\circ}C$ for 2 weeks. The cultures showing archaeal growth were transferred using the dilution-to-extinction method. 16S rRNA gene PCR-Denaturing Gradient Gel Electrophoresis was used to identify the enriched archaea in the highest dilutions where archaeal growth was observed. Most of cultured archaea belonged to genus of Thermococcus (T. alcaliphilius, T. litoralis, T. celer, T. barossii, T. thoreducens, T. coalescens) with 98-99% 16S rRNA gene similarities. Interestingly, archaeal growth was observed in the cultures with Iron (III) and nitrate as an electron acceptor. It was supposed that archaea might use the elemental sulfur generated from oxidation of the reducing agent, sulfide. To cultivate diverse archaea excluding Thermococcus, it would be required to use other reducing agents instead of sulfide.

• Journal of computational fluids engineering
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• v.17 no.4
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• pp.49-55
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• 2012

Research has importance in proposing the design of a tunnel with a vertical vent to secure passengers in a comfortable environment and safe against pressure. Using several analysis methods, the magnitude of the pressure induced by the vertical vent in the tunnel can be analyzed. In addition to the 3-dimensional method, the 2-dimensional method and the 2-dimensional axis-symmetric method are also used to analyze the strong and weak points of each so that the optimum analysis method can be obtained. As a result, it appears that the 2-dimensional axis-symmetric method is the most suitable in analyzing tunnel pressure consider to accuracy and time effective aspect. Also, the 3-dimensional method is disadvantageous in that it takes longer in calculating results, but is more effective in predicting phenomena around the vertical vent in the tunnel.

• Food Engineering Progress
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• v.21 no.2
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• pp.110-115
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• 2017

This study aimed to identify milling characteristics depending on the number of a cutting roller's air vent and blowing velocity to remove rice bran by the cutting type milling machine which can minimize the conventional milling process. The level of whiteness was found to be $38{\pm}0.5$ in all the conditions, showing consistent whiteness levels during milling. The rice temperatures turned out to be 15.4 and $14.6^{\circ}C$ which were rather low-level under the conditions of the cutting roller with 3 vents and blowing velocities of 35 and 40 m/s respectively. Cracked rice ratio was 2.13% under the conditions of the cutting roller with 3 vents and a blowing velocity of 35 m/s. Broken rice ratio showed the range of 0.762-0.869%, reflecting a low level. Turbidity after milling was decreased, as blowing velocity became faster. Energy consumption for milled rice production was decreased, as blowing velocity became faster. The optimum milling condition for cutting type milling machine depending on air vent number of cutting roller and blowing velocity was found to be 3 vents and 35 m/s.