• 한국농공학회지
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• 제25권4호
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• pp.29-37
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• 1983

This study was carried out not only to prepare available materials that can be utilized in basic planning of irrigation reservoirs, but also to contribute to the study on countermeasures for reasonable irrigation water development in Korea in the future, through the investigation for the structural characteristics of reservoirs and their change trend by an epoch. During this study 123 sites of sample reservoirs were analysed in their dimensions of physical constituent factors. The physical characteristics and their change trends revealed by this study are summarized as follows: 1. For the irrigation earth dam in Korea the correlation between dam volume (v) and dam height & length (H$^2$L) can be described as the formula of v=1. 434H2L~17, 300 (r=0. 933), from which embankment amount is assumed to be quickly estimated under determined dam height and length of the proposed reservoir. 2. The ratio of dam volume to dam height & length ranges approximately from 0.5 to 3 (1.7 in average), that of storage capacity to dam volume 2 to 10 (8.4 in average), that of irrigation area to full water surface area 5 to 20 (13 in average) and that of catchment area to irrigation area 2 to 5 (4 in average). Though correlation between dam volume and dam height & length is high, that between others is relatively low. 3. Average storage depth ranges approximately from 4m to l0m (6.6m in average), unit storage capacity 0. 4m to 0. 8m (0.54 in average) and shape factor of dam 5 to 20 (10.5 in average). 4. The more recently planned the reservoirs were, the less storage capacity, dam volume, full water surface and dam shape factor they have. 5. The more recently planned the reservoirs were, the larger storage depth and unit storage capacity they have.

• 한국식품조리과학회지
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• 제1권1호
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• pp.40-44
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• 1985

The change of PH, texture, swelling$.$power and protein, fat, calorie composition at cooking rice boiling with various cereal were summarized as follows : 1. The change in pH resulting from the addition of various cereal were much more pronounced in boiling rice with cereal than boiling rice. 2. The volume of boiling rice with cereal was higher that the addition of various cereal. 3. The evaluation of the texture of boiling rice with cereal was the most that rice 70％, barly, bean, red-bean each 10％ composition.

• 한국주조공학회지
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• 제15권2호
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• pp.184-193
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• 1995

Effects of process parameters during thixocasting, such as solid volume fraction, mold temperature and extrusion ratio, on the mold filling behaviour and fluidity of Mg alloy(AZ91D) have been investigated. The semi-solid ingot held for 60 minutes at the semi-solid temperature range did not contain the equilibrium volume fraction of solid as expected from the phase diagram. Therefore, in order to obtain the desired solid fractions, and to suppress the exaggerated grain growth during heating, it was required to heat the ingot rapidly up to the temperature $10^{\circ}C$ higher than the semi-solid temperature suggested from the phase diagram for a specific volume fraction of solid. The experimental results show that mold filling behaviour and fluidity can be improved with the use of the higher mold temperature and the lower volume fraction of solid, but remain nearly unaffected by the change of extrusion ratio.

• Journal of Welding and Joining
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• 제15권3호
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• pp.47-55
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• 1997

Dynamic characteristics of the short circuit mode are investigated using the Volume of Fluid (VOF) method. When the initial molten drop volume, contact area and wire feed rate are given, rate change of the molten bridge profiles, pressure and velocity distributions are predicted. The electromagnetic force with proper boundary conditions are included in the formulation to consider the effects of welding current. It is found that the molten metal is transferred to the weld pool mainly due to the pressure difference caused by the curvatures in the initial stage, and electromagnetic force becomes dominant factor in the final stage of short circuit transfer. Necking occurs at the contact position between the molten drop and weld pool, and the initial molten drop volume and welding current have significant effects on break-up time.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제25회 KOSCI SYMPOSIUM 논문집
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• pp.223-229
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• 2002

Spark plug ionization signal could be useful in an internal combustion engine as a feedback signal for combustion diagnostics such as misfire detection, knocking detection and lambda control, but the signal has high level of cyclic fluctuation in an internal combustion engine due to residual gas, pressure, temperature, mixture composition in the spark gap. Because of this reason it is very difficult to apply ion signal to commercial engine control. In this Study, a correlation between A/F and spark plug ionization signal was studied in a constant volume chamber. Constant volume chamber with gas phase fuel(Propane) has homogeneous fuel composition , no mixture flow, same pressure and temperature on each test. The results show that mean chemi-ion signal has the highest correlation with A/F and intial pressure change has on effect on the thermal-ion signal and not on chemi-ion signal.

• KSTLE International Journal
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• 제4권1호
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• pp.31-36
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• 2003

Sliding and impact/sliding wear test in room temperature air and water were performed to evaluate the effect of spring shapes on the wear mechanism of a fuel rod. The main focus was to quantitatively compare the wear behavior of a fuel rod with different support springs (i.e. two concaves, a convex and a flat shape) using a ratio of wear volume to worn area (De)-The results indicated that the wear volumes at each spring condition were varied with the change of test environment and loading type. However, the relationship between the wear volume and worn area was determined by only spring shape even though the wear tests were carried out at different test conditions. From the above results, the optimized spring shape which has more wear-resistant could be determined using the analysis results of the relation between the variation of De and worn surface observations in each test condition.

• 소음진동
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• 제9권2호
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• pp.285-294
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• 1999

Transient analysis for compressible fluid flow has been performed experimentally and analytically to study the dynamic characteristics of the end volume transmission lines following a sudden pressure change a its entrance. The numerical method was developed based on the method of characteristics. The sudden pressure at its entrance was generated by rupture of diaphragm in a shock tube. The sudden pressure was used to obtain the response, as input signal for the numerical analysis. The response to the sudden pressure at the end volume was measured using a pressure transducer. The experimental result shows good agreements with the numerical result. The effects of tube length, its diameter and end volume magnitude are evaluated on the responses of the pressure and on the damping factor. It is found that the viscous damping effects on the response through the transmission pipeline becomes larger with increasing pi;eline length and decreasing diameter of the pipe and the fluid-elastic stiffness decreases with increasing the terminal volume. The numerical approach presented in this paper can be very useful in designing the instrument and control system.

• Bulletin of the Korean Chemical Society
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• 제5권3호
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• pp.112-117
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• 1984

The association constants (K) of 3,5,N-trimethyl pyridinium iodide in 95 volume percent ethanol-water mixed solvent were determined by a modified UV and conductance method at $25^{\circ},\;30{\circ},\;40{\circ}\;and\;50{\circ}C$ over the pressure range 1 to 2000 bars. The association process is enhanced with increasing pressure and decreasing temperature. From K values, we obtained the total partial molar volume change (${\Delta}V$) and some thermodynamic parameters. The electrostriction volume (${\Delta}V_{el}$) and intrinsic volume (${\Delta}V_{in}$) were also evaluated. The values of ${\Delta}V,\;{\Delta}V_{el},\;{\Delta}V_{in}$ are negative, negative and positive, respectively, and the absolute values of all these three decrease with increasing pressure and temperature. The ion-pair size (a) were varied 3 to 6 ${\AA}$, with pressure and temperature. The solvation number (n) decreased from 2 to 0.5 with increasing temperature.

• 한국산업보건학회지
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• 제24권4호
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• pp.492-500
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• 2014

Objectives: The purpose of this study is to estimate the applicability of regional sample collection of environmental samples. The concentration of asbestos fibers were analyzed with two devices. One was an existing commercial air sampling pump that has been proved to be accurate and exact, and the other is a remodeled pump for sample collection which was made from an electric bubble generator originally designed for aquarium fish. Samples were collected with the two devices under the same environmental conditions and collection equipment. A comparative analysis of the concentration of ambient asbestos fiber was then performed. Methods: Based on previous research, six farmhouses with asbestos fiber slate roofs known to have high concentrations of asbestos fiber were selected. Using the existing commercial air sampling pump and the remodeled electric bubble generator, four to seven samples were collected each day one meter downwind from the edge of the slate roof at high volume (about 4 L/min) and low volume (about 1.4 L/min). The analyzer responsible for sample quality control of asbestos fibers counted the number of asbestos fibers with a phase microscope. Results: The rates of flow change of the existed sampler and the remodeled pump at high volume were 0.82% and 0.17%, respectively. The rates of flow change at low volume were 3.83% and 1.09%, but there was not significant difference. The rates of flow change are within the error range (${\pm}5%$) of OSHA analyzing methods. For the high volume sampler, the average asbestos fiber concentration in the air collected by the existed sampler is 6.270 fibers/L and for the remodeled one 5.527 fibers/L, not a significant difference. For the low volume sampler, the average asbestos fiber concentration in the air collected by the existed sampler is 7.755 fibers/L and for the remodeled one 7.706 fibers/L, not a significant difference. The total area of the slate roof of the targeted farmhouse has an effect on the concentration of asbestos fibers in the air from the existing pump and the remodeled one (p<0.01). Conclusions: The sampling function between the existing commercial pump and the remodeled one shows little difference. Therefore, the remodeled pump is considered a pump with a good availability for collecting ambient air asbestos samples.

• 한국식품영양과학회지
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• 제38권10호
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• pp.1430-1437
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• 2009

다시마를 Vibrio sp.로 분해하여 제조한 SCD로 기능성 빵을 만들기 위하여 mixture design을 이용한 원료의 최적 배합 비율을 구하였다. 다시마 SCD 빵의 max weight, strength, hardness 및 비용적의 값은 밀가루와 물의 첨가량이 증가할수록 감소하는 반면, SCD의 첨가량이 증가할수록 증가하였다. 밀가루와 물의 첨가량이 증가할수록 SCD의 첨가량이 감소할수록 발효팽창력의 값은 증가하였다. 밀가루의 첨가량이 증가할수록 SCD의 첨가량이 감소할수록 SCD 빵의 L(명도) 값과 b(황색도) 값은 증가하였으며, 밀가루와 물의 첨가량이 증가할수록 SCD의 첨가량이 감소할수록 다시마 SCD 빵의 a(적색도) 값은 감소하였다. ANOVA 분석에 의한 다시마 SCD 빵의 max weight, strength, hardness, 비용적, 색도 b(황색도) 값 및 수분흡착력은 linear model이 결정되었으며, distance, 발효팽창력, 색도 L(명도) 및 a(적색도) 값은 nonlinear model(quadratic model)이 선정되었다. Constraint coefficient 값의 분석 결과 SCD는 SCD 빵의 texture에 가장 큰 영향을 주었으며, 물은 발효팽창력, 비용적 및 수분흡착력에 가장 큰 영향을 미쳤다. 또한 밀가루는 SCD 빵의 색도에 가장 큰 영향을 미쳤다. Distance에서는 flour-SCD 및 water-SCD 상호작용이 있었으며, 발효팽창력에서는 flour-SCD 상호작용이 있었다. 또한 SCD 빵 색도의 L(명도)에서는 flour-SCD의 상호작용이 나타났으며, a (적색도)에서는 flour-SCD 및 water-SCD 상호작용이 있었다. Mixture(modified distance) design에 의해 결정된 다시마 SCD 빵의 밀가루, 물 및 SCD의 최적 배합비율은 각각 48.25, 30.89 및 3.86%이었다. 관능검사 결과 전해수로 처리한 SCD 빵은 시중제품보다 모든 면에서 품질이 낮았으나, 전해수 처리 SCD 빵은 대조구(전해수 미처리)보다 월등히 높은 점수를 받아 전해수로 처리된 SCD 빵의 맛, 조직감 및 향을 개선한다면 SCD의 산업화가 가능할거라 판단된다.