• 동력기계공학회지
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• 제13권5호
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• pp.25-33
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• 2009

In the present study, the numerical investigation has been carried out to see the effects of water mist sprays on the fire suppression mechanism. The special-purposed program named as FDS was used to simulate the interaction of fire plume and water mists. This program solves the fire-driven flows using LES turbulence model, the mixture fraction combustion model, the finite volume method of radiation transport for a non-scattering gray gas, and conjugate heat transfer between wall and gas flow. The computational domain was composed of a rectangular space dimensioned as $L{\times}W{\times}H=4.0{\times}4.0{\times}2.5\;m^3$ with a mist-injecting nozzle installed 1.0 m high from the fire pool. In this paper, two types of nozzles were chosen to compare the performance of the fire suppression. Numerical results showed that the nozzle, type A, with more orifices having smaller diameters had poorer performance than the other one, type B because the flow injected through side holes deteriorated the primary flow. The fire-extinguishing time of type A was 2.6 times bigger than that of type B.

• Journal of Biosystems Engineering
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• 제26권4호
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• pp.355-362
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• 2001

Uniform application of agri-chemicals will improve orchard pest management. An air-blast(orchard) sprayer designed for vineyards has been used: however, few research on the uniformity and coverage of the sprays has been reported. Distributions of spray coverage were measured with artificial targets and analyzed to enhance the efficiency of spray application. A structure was built to place water sensitive papers, sampling spray droplets blasted from the orchard sprayer. The sampling cards were collected from five directions at three distances (2.5, 3.0 and 3.5m) for two fan speeds (2,075 and 3,031 rpm), and analyzed using an image analysis system. The distribution of the coverage percent area did not follow the wind velocity pattern. The coverage by the low fan speed was more uniform and higher than that by the higher fan speed. The coverage percent area decreased with an increase of distance. The distribution of droplet density was similar to that of coverage. However, the coverage contribution by smaller droplets became more significant as the distance increased. The upward blasting distance was limited within 3m, but the limit to the ground level was expanded the distance more than 3.5m because of the concentrated droplets.

• 대한기계학회논문집B
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• 제30권12호
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• pp.1236-1242
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• 2006

The local heat flux of spray cooling in the film boiling region were experimentally investigated for the spray region of $D_{max}$ = $0.005{\sim}0.03m^3/(m^2s)$. A twin-fluid full cone spray nozzle was employed for the experiment and the distributions of droplet flow rates were obtained for air-water full cone sprays. A stainless steel block was cooled down from initial temperature of about $800^{\circ}C$ by full cone spray. In the region near the stagnation point, it was found that the experimental data are in good agreement with the results predicted from the correlations between the local heat transfer and the local droplet flow rate proposed in the previous report. However, it was found that the experimental data of $D_r$ > $0.01m^3/(m^2s)$ are a little smaller than the results predicted from the correlations.

• 농업과학연구
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• 제37권3호
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• pp.355-360
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• 2010

This experiment was focused to determine the effect of preharvest treatment of alkaine-reduced water (ARW) and $CaCl_2$ on the storage of oyster mushroom. ARW was prepared through electrolysis of water with $CaCl_2$ (0.1%) as salts and $CaCl_2$ (0.1%) was dissolved in deionized water. Mushrooms were harvested after two sprays of each solutions and quality factors including firmness and browning was determined during storage. The severity of browning was more greater when stored 20 days. Unlike $CaCl_2$, ARW containing 139 ug/L calcium was positive on maintaining freshness in terms of delay of firmness loss and respiration drop, keeping soluble carbohydrate content such as trehalose, and inhibiting the occurrence of browning. Browning, however, seemed to be more influenced by the developmental stage of mushroom at harvest. Even no significant difference was found, the level of ${\beta}$-glucan was low in ARW treatment compared to that of control. Further research including application and preparation methods of ARW is required to clarify the potential of ARW on keeping freshness of oyster mushroom through inhibiting tissue browning.

• 한국분무공학회지
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• 제5권4호
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• pp.40-46
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• 2000

To understand the basic the structure of the spray field and to obtain the initial conditions for computational models for shear coaxial twin-fluid injectors. the atomization characteristics under different flow and geometric conditions were examined. The spray characteristics such as SMD, mean axial and radial velocities, Dia. of droplets and volume flux with a P.D.P.A. Water and nitrogen gas under atmospheric conditions were used as a test fluids. The drops produced by shear coaxial injectors continue to disintegrate along the spray axis and decrease their sizes. SMD was the maximum at the spray center of spray and decreased with increasing radial distance. The results of this parametric study showed that SMD decreased with increasing gas injection velocity as well as with decreasing liquid injection mass flow rate, The relative velocity between gas and liquid flow played a significant role resulted in decreasing SMD and in spreading the spray. Recessing the liquid orifice resulted decreasing SMD and a spreading the spray. Recess of liquid orifice by 5.0mm showed best atomization characteristics in this experiment. Although drop diameter changes, shear coaxial injector sprays had constant velocity and exhibited a high degree of radial symmetry.

• 제어로봇시스템학회논문지
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• 제21권8호
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• pp.713-717
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• 2015

In this paper, we propose camber monitoring system which is using on hot rolling process. In roughing mill which is one of the rolling part in hot rolling process, steel plate can be bended in width direction under the imbalance of rolling condition. This bending of steel plate in width direction is called as camber. In order to measure the camber, first, cameras which are installed over transport pathway of steel plate take pictures of whole shape of steel plate. And location value of steel plate edge is extrated from these pictures by edge detection algorithm. But, there are a lot of noises which are generated by such as water sprays, dusts, peripheral equipments in these pictures, and these noises make edge detection difficult. In order to solve this kind of problem, we developed a direction selective edge detection algorithm, and applicated in our camber monitoring system. As a result, we got stable results in spite of process noises.

• 한국추진공학회지
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• 제3권1호
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• pp.9-14
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• 1999

작동조건이 두개의 공기충돌형 연료분사장치로부터 분사되는 이중분무 특성에 미치는 영향을 공연비 1.36∼3.54의 범위에서 실험적으로 수행하였다. 물과 질소가스가 실험유체로서 사용되었다. 분무 액적의 분포특성은 질량분포와 순간영상 촬영법에 의하여 측정되었다. 실험적 결과는 ROA(축방향에 대한 반경방향 공급압력비)의 증가에 따라 질량분포곡선의 최대값은 낮아지면서 더 넓은 영역에 걸쳐 분포하였으며 공급유체의 증가에 따른 질량중심점의 위치는 변화가 없었다. 노즐간격 증가는 간섭영역에서의 질량분포에는 커다란 영향을 미치지는 않았으나 더 넓은 영역에 걸쳐 분포하려는 특성을 보여주었다. 또한, ROA 비가 증가할수록 충돌중심점 근처에서 간섭의 영향은 작아짐을 중첩법을 이용하여 비교함으로서 잘 알 수 있었다.

• Journal of Pharmaceutical Investigation
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• 제34권2호
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• pp.131-138
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• 2004

This study was aimed to investigate the feasibility of nasal delivery of caffeine for the elimination of sleepiness. The effects of various vehicles, solubilizers, and enhancers on the permeation of caffeine through rabbit nasal mucosa was observed. The permeation study was carried out using a Franz-type permeation system at $37^{\circ}C$, and the amount of caffeine permeated though the rabbit nasal mucosa was determined by a validated HPLC. The apparent solubility and phys iochemical stability of caffeine in various nasal formulations were was determined. The effect of hydrotropes and modified cyclodextrins on the solubility of caffeine in water was determined by equilibrium solubility method. The solubility of caffeine in water was 29 mg/mL at $30^{\circ}C$. The addition of sodium benzoate and nicotinamide at 10% improved the solubility of caffeine (115 and 132 mg/mL, respectively) in aqueous solution. The flux of caffeine though the nasal mucosa from aqueous solution was $2.1{\pm}0.26\;mg/cm^2/hr$. The addition of sodium benzoate reduced its permeation $(1.4{\pm}0.01\;mg/cm^2/hr)$, but sodium benzoate with 5% $2HP{\beta}CD$ and 0.03% monoterpenes increased its permeation $(2.4{\pm}0.04\;mg/cm^2/hr)$ markedly. The addition of nicotinamide also increased also increased its permeation $(2.5{\pm}0.36\;mg/cm^2/hr)$. markedly. As the concentration of caffeine in nasal formulation increased, the permeation flux increased linearly. Caffeine was stable physicochemically and enzymatically in the nasal mucosa extract at $37^{\circ}C$. These results suggest that caffeine can be efficiently delivered nasally and the development of nasal formulation will be feasible.

• 한국도로학회논문집
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• 제15권5호
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• pp.11-20
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• 2013

PURPOSES : This study is to suggest time to spray curing compound, the amount of curing compound, and the number of times to spray curing compound based on indoor tests. METHODS : Based on the literature review, two methods are used in this study, One is test for water retention of concrete curing material and the other is test for abrasion resistance of concrete surfaces by the rotating-cutter method. Through those methods, curing compound was evaluated. RESULTS : The result of the laboratory experiment for time to spray curing compound indicates that 30 minutes after placing concrete is optimal. For the amount of curing compound, $0.5{\ell}/m^2$ is the minimum quantity for both concretes. Through test of the number of times to spray curing compound, method to spray the whole amount of curing compound in twice is more efficient than it to spray the whole amount at a time. Also, method of separately 30-50 minutes spray is better than method of separately 10-30 minutes spray. CONCLUSIONS : From the testing results, it can be proposed that optimum time to curing compound is $30{\pm}15$ minutes, $0.5{\ell}/m^2$ is efficient for spraying the whole amount of curing compound at a time, and $0.4{\ell}/m^2$ is the best for spraying the whole amount of curing compound in twice, which sprays it in 20 minutes after 30 minutes from placing concrete.

• The Plant Pathology Journal
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• 제22권3호
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• pp.283-288
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• 2006

Trichoderma harzianum YC459 (Th 459), isolated from sawdust compost, was effective in controlling cucumber and tomato gray mold caused by Botrytis cinerea under controlled and plastic film tunnel conditions. A water suspension of the wettable powder formulation of Th 459 significantly $(P\leq0.05)$ reduced the severity of cucumber gray mold by foliar spraying at all tested concentrations from $10^5\;to\;10^8$ colony forming unit (cfu)/ml in repeated experiments. The control efficacy was maintained at least seven days with the average control value of 70% in cucumber pot tests. Mixing one to eight grams of the granular formulation ($10^8cfu/g$ dry weight) of Th 459 into one liter nursery potting mix at seeding also significantly $(P\leq0.05)$ reduced the severity of cucumber gray mold by suppression of lesion formation three weeks after treatment. Application of mixing granular formulation at seeding in combination with foliar spraying during cultivation provided a more significant reduction $(P\leq0.05)$ of cucumber gray mold than granule mixing or leaf spray alone. The foliar spraying of the formulated wettable powder of Th 459 significantly $(P\leq0.05)$ reduced the infection of tomato fruits by B. cinerea as effective as the chemical fungicide, dichlofluanid, in three plastic film tunnel experiment trials. It is suggested that effective control of gray mold of cucumber and tomato can be provided by both treatment of Th 459 into potting mix and foliar spray through induction of systemic resistance and direct inhibition of the pathogen.