• 대한화장품학회지
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• 제19권1호
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• pp.85-107
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• 1993

화장품에 사용되는 미분체의 혼합특성을 알기 위하여 화장품용 미분체 혼합기인 ribbon mixer, powder mixer micropulverizer, fine impact mill에 미립자, 구상 및 판상의 형태를 가진 bulk powders를 혼합시간을 변화 시키면서 혼합하는 실험을 하였다. 혼합분체의 혼합정도를 평가하기 위하여 산화철을 tracer로 사용하였으며, 원료 및 혼합물의 particle size distribution, specific surface area, density 및 표면색상을 측정하였다. 미분체 혼합물의 혼합시간과 표면색상변화, 입도분포 및 비표면적과의 사이에 대수적 1차 상관관계가 성립되었고, 색상의 변화로부터 혼합정도를 평가할 수 있는 간단한 식을 도출하였다. 사용된 혼합기에 대해 혼합기구별 modelling과 혼합에 따른 입도 분포 및 비표면적의 변화로부터 혼합기 impellar tip에서의 linear velocity별 혼합기는 대류혼합, 전단혼합 및 확산혼합으로 분류되었다.

• 한국운동역학회지
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• 제15권3호
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• pp.133-142
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• 2005

The purpose of this study was to compare of the kinematic variables from takeoff preparation to takeoff used by long jumpers who recorded over 8meters in 2002 Busan Asian Game and 2003 Daegu Universiade and 2001 national championship. The kinematic characteristics from the last three stride to takeoff at the takeoff board were analyzed such as velocities, heights and angles. The conclusion were as follows; In order to record over 8meters the national long jumpers should have under 5cm height variation at the penultimate stride of the run-up. In the approach phase the horizontal velocity of the jumpers should reach to 10m/s in touchdown at takeoff board The vertical velocity must have 3.75m/s simultaneously in order to record 8meters. The jumpers need to continue talent of the horizontal velocity in touchdown at takeoff board and require jumping power of the takeoff leg at takeoff board The appropriate body variation range ratio between takeoff and touchdown should be 1.2 vs 1 and the trunk angle at touch down on the board should be close to the erect posture for higher body flight.

• Journal of the Korean Wood Science and Technology
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• 제47권5호
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• pp.633-643
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• 2019

Growth characteristics [stem diameter (D), tree height (H)] and wood properties [Pilodyn penetration (P) and stress-wave velocity (SWV)] were measured for 65 families of 6-year-old Acacia mangium trees planted in Indonesia, in order to characterize their variation in D, H, P, and SWV. Therefore, the correlations between the measured characteristics were also determined, and their significant differences observed. Furthermore, their low to moderate values of narrow-sense heritability was obtained, and the results indicated the characteristics to be genetically controlled in A. mangium. In addition, highly significant positive correlations were observed among the growth characteristics, suggesting a close relationship, while there was no significant association between the growth characteristics and P, as well as SWV, indicating their independent. Therefore, these results demonstrate a potential for the improvement of both growth and wood properties of A. mangium trees, using the appropriate breeding programs. In addition, 18 families showed good performance in D and SWV, signifying their positive prospect of being considered as plus trees for the next generation breeding cycles.

• 한국산업보건학회지
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• 제3권2호
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• pp.204-212
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• 1993

This study was conducted to evaluate ventilation efficiency of 4-stage slot hood by variation of slot width, flow rate, hood size and baffle size. The slot velocity, control velocity and plenum velocity were related to slot width and the distance between source of contamination and hood. The results obtained from laboratory experiment for local exhaust ventilation systems were as follows ; 1. When slot widths were constant(equally changed) and the velocity was 6-10 m/s, the slot velocity from 1st slot to 4th slot gradually decreased. As the slot width-to-slot length ratio(WLR) decreased, the slot velocity of each stage increased. But if WLR value was less than 0.04, the slot velocity decreased. 2. When slot velocity exceeded 10 m/s with constant slot widths, the slot velocity of each stage was uniform. 3. When the slot velocity was uniform within 10 m/s and the first slot width was 14-20 mm, the slot width ratio between 1st slot and each of three other slots were 1, 1.25, 1.5 and 3.0, respectively. 4. The slot and plenum velocity were uniform when exhaust flow rate changed from 14 to $19m^3/min$ and there were no hood splitter vanes. 5. When the slot velocity at each stage was uniform, the control velocity at site 30 cm away from hood No.2 increased from 0.15-0.30 to 0.25-0.45 m/s and the control distance from 20 to 30 cm(about 1.5 times).

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.1328-1332
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• 2006

As the city is developed, Sewerage outlet is installed for the discharge of rainfall special at new town or modified the existed sewerage network. But the sewerage outlet is influenced to the cannel flow. In this paper, for analyzing variation of flow properties by installing sewerage outlet, it was experimented a with $120^{\circ}$ channel junction. The water depth is rapidly increasing at the just before sewerage installed position, but the velocity is represented increasing at the just after sewerage installed position. In addition, the biggest increment of water depth and velocity is represented $3.0m^3/hr{\sim}4.0.m^3/hr$. At the position of the sewerage outlet installation, separate install at up and downstream is rather than only one position at up or down stream. If it was not install both installation, the upstream installation is better than downstream installation.

• Water Engineering Research
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• 제4권3호
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• pp.127-139
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• 2003

This paper presents the hydraulic analysis of the oxygen transfer through the air entrainment and the relationships between the efficiency of the oxygen transfer and the hydraulic parameters in the riparian riffles. Field survey on the pool-riffle formation of the river reach and the measurements of the oxygen transfer in the riffles were performed. Air entrainment occurred more frequently in the edged gravels rather than in the round and edgeless ones, and it was formed mainly from behind the trailing edges of the gravels. Oxygen transfer was found to be proportional to the flow velocity, the flow discharge, and the Froude number, but to be not closely related to the particle diameter. Average value of oxygen transfer in the riffles of study area was about 0.085, which shows good efficiency compared with results of smooth chute. Variation of the water level, which increases in proportion to the flow velocity and the flow discharge, seems to make the air entrainment more active, but has not been verified quantitatively. Relationships between the air entrainment and the variation of the water level must be considered in the further study.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.262-268
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• 1998

This study were performed to find the cooling effect and to provide design data during summer season. for the Pad ＆ Fan system of Venlo type greenhouse. The temperature and humidity variation along the greenhouse width and wind velocity in the greenhouse were surveyed. Also, the influence of shading on the cooling effect were analyzed. While Pad ＆ Fan system were operated, the temperature, humidity and wind velocity in greenhouse were different by the distance from the Pad and the height from the ground. The temperature difference between Pad and Fan was about 8.1$^{\circ}C$~10.4$^{\circ}C$ without shading and about 4.4$^{\circ}C$~5.5$^{\circ}C$ with shading.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.623-628
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• 2001

The objective of this study is to find out the effect of Horizontal vibration on the compressive strength for 7 days and 28 days cured concrete specimens according to the kind of fine aggregates and the variation of vibration velocities, and times began to vibrate. Three kinds of fine aggregate(river sand, sea sand, crush sand), three types of vibration velocities(0.25, 0.5 0.1kine(cm/sec)), and four steps of times(0, 3, 6, 9 hours after concrete casting) were chosen as the experimental parameters in this study, the vibrations are applied for 30 minutes in each case. From this study, the variation with type of fine aggregate doesn't show tendency and the compressive strength decreases with increasing vibration velocity. When the vibration force time is more than 6 hour, It shows that compressive strength decreases under the condition of vibration velocity which the value is 0.5 kine and 1 kine, respectively.

• 한국산업융합학회 논문집
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• 제10권4호
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• pp.275-283
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• 2007

This study aims at the calculation of a variation of flow characteristics of main channel for tributary inflow in river junction. So this study was analyzed the variation of flow depth and velocity in main channel for a change of inflow degree. For this purpose, FLDWAV model are carried out for variations of $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$ tributary inflow at junction. Results show that velocity ratio(V1/V3) increases and flow depth ratio(H1/H3) decreases for discharge ratio(Q1/Q3) of upstream and downstream when degree increases in junction. And FLDWAV model was applied at a real river junctions. Selected area is a junction of Gumho river and Sin stream. Results show that pattern is similar to a virtual channel.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1997년도 추계 학술대회논문집
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• pp.120-125
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• 1997

In the present work the influence of various physical parameters on the two-phase flow behavior in a self-heated porous medium has been studied using a numerical model, that is, the effects of heat generation rate, of porosity, of particle size, and of system pressure on the dryout process. To analyze the effect of these parameters, the variation of both liquid volumetric fraction (i.e., liquid saturation) and liquid axial velocity is evaluated at the steady state or at the onset of a first boiled-out region. The analysis of computational results indicate that a qualitative tendency exists between the parameters such as heat generation rate, porosity, effective particle diameter and the temporal development of the liquid volumetric fraction field up to dryout. In addition to these parameters, a variation of fluid properties such as phase density, phase viscosity due to a change of system pressure can be used for gaining insight into the nature of two-phase flow behavior up to dryout.