• 대한정형도수물리치료학회지
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• 제19권2호
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• pp.31-37
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• 2013

Background: The purpose of this study was to identify the effects of cervical manipulation for improve blood velocity and flow in the subjects with asymmetric vertebral artery. Methods: Twenty-four subjects on asymmetric vertebral artery with right side have less blood flow than left side participated in this study for apply to non-specific cervical manipulation on lower portion. Measurement method were using duplex ultrasound with colour doppler imaging for blood velocity and flow on left and right vertebral artery. Results: Compared changes of blood velocity and flow on unilateral after the cervical manipulation, the left blood velocity decreased significantly (p<.01) and the right blood velocity increased significantly (p<.01). The left blood flow no significant changes and the right blood flow increased significantly (p<.01). Compared changes of blood velocity and flow on bilateral, the left and right blood velocity and flow made significantly difference on pre-manipulation (p<.01). However, both side no significantly difference on post-manipulation. Conclusions: These findings suggest that the non-specific cervical manipulation took effect for improve blood velocity and flow in the subjects with asymmetric vertebral artery. Therefore, therapeutic approaches for improve to asymmetric vertebral artery should be consider non-specific cervical manipulation.

• 보존과학연구
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• 통권31호
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• pp.31-42
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• 2010

This study were performed thermal shock test for four kind of different rocks (Iksan granite, Namsan granite, Jeongseon marble, Yeongyang sandstone), and according to heating temperature($400^{\circ}C$, $600^{\circ}C$) on samples were investigated physical properties such as specify gravity, porosity, p-wave velocity. As a result, the tendency was appeared that porosity increased, and specific gravity and p-wave velocity decreased at a more higher temperature. But, the situation of change appeared characteristic according to temperature and rock types. In the case of Yeongyang sandstone, it appeared in especially porosity increasing at $400^{\circ}C$. The specific gravity was little change in the all the rock at $400^{\circ}C$ but the decreased at $600^{\circ}C$. Therefore the specific gravity in the temperature range is due to the relatively small impact on the change is expected. Porosity of the granite at $400^{\circ}C$ changes little. but marble in the rate of change is large. Conversely, the sandstone porosity decreased. At $600^{\circ}C$ increased porosity in all of rocks. particularly sandstone the smallest increase in porosity. Experiments showed that p-wave velocity measured through dry rocks was sensitive to quantify the thermal damage. The p-wave velocity of all rocks decreased with increasing temperature. In the relation between porosity and p-wave velocity, p-wave velocity decreased with increasing porosity. On the other hand, in case of Yeongyang sandstone p-wave velocity decreased with decreasing porosity. thus, development of microcracks more affects p-wave velocity than porosity. In this study, damage intensity was well explained with porosity and p-wave velocity values depending on temperature increase.

• 멤브레인
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• 제13권4호
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• pp.219-228
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• 2003

분리막을 이용한 정수처리 공정의 최적화를 위하여 유기물 성분인 humic acid와 탁도를 유발하는 kaolin을 모사 용액으로 제조하여 막내 비저항 값을 최소화하면서 flux의 안정된 경향을 나타내는 최적의 운전 조건을 검토하여 보았다. 그 결과 압력이 증가함에 따라 낮은 비저항값에서 효율적인 분리막을 운전할 수 있으며 선속도가 증가함에 따라 높은 전단율에 의해 cake load는 줄어들었으며 이에따라 비저항값과 flux는 증가하는 경향을 나타내었다. 따라서 최적의 운전조건은 압력 $2.0 kg_f/cm^2,$ 선속도 0.92 m/sec으로 알 수 있었다.

• 펄프종이기술
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• 제32권4호
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• pp.10-17
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• 2000

The change of fiber length, freeness, initial forming drainage velocity, specific filtration resistance, final drainage time and wet web dryness were measured to investigate the effect of the refining load on the drainage characteristics of pulp. The arithmetic average fiber length after refining with higher refining load was shorter than that obtained with lower refining load. Higher refining load decreased initial forming drainage velocity, final drainage time and wet web dryness. The refining load also affected the relationship between freeness and specific filtration resistance, initial forming drainage velocity, final drainage time. It was found that the specific filtration resistance is better than freeness to predict the drainage characteristics of pulp and the wet dryness.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.148-154
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• 2004

As a rocket propellent of hydrocarbon fuels, the characteristics of liquefied natural gas was evaluated with the viewpoint of the constituents and content, the cooling performance as a coolant, and characteristic velocity and specific impulse as parameters of the engine performance. Content of methane was a principal factor to determine the characteristics as a rocket propellant and more than 90 % of it was needed as a fuel and coolant in the regenerative cooled liquid rocket engine. Some constituents of the liquefied natural gas can be frozen by the pre-cooling of the pipe lines, therefore they can be a factor disturbing the normal working of engine. In case the content of methane is around 90% in the liquefied natural gas, a normalized stoichiometric O/F mixture ratio of 0.75 is suggested for a nominal operation condition to get the maximum specific impulse and characteristic velocity.

• Wind and Structures
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• 제35권6호
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• pp.395-403
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• 2022

The present research is concerned with the study of Stoneley wave propagation at the interface of two dissimilar homogeneous orthotropic magneto-thermoelastic solids with fractional order theory of type GN-III with three phase-lags and combined effect of hall current and rotation. With the help of appropriate boundary conditions the secular equations of Stoneley waves are obtained in the form of determinant. The characteristics of wave such as phase velocity, attenuation coefficient and specific loss are computed numerically. The effect of rotation on the Stoneley wave's phase velocity, attenuation coefficient, specific loss, displacement components, stress components and temperature change has been depicted graphically. Some particular cases are also derived in this problem.

• Journal of the Korean Wood Science and Technology
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• 제26권4호
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• pp.26-33
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• 1998

Acoustical properties of chestnut and paulownia woods have been determined in four film thicknesses of oriental lacquering and cashew varnishing on double surfaces of soundboard to elucidate effects of finishing. Accelerometer was attached to the specimen at one third position from one end, and specimen was hit by the impact hammer at one third position from opposite end. Data were processed by vibration analyzer. The ratio of axial-to-transverse sound velocity of untreated specimens of chestnut and paulownia were 3.25 and 5.34, respectively. Natural frequency, specific Young's modulus, acoustical coefficient, sound velocity, damping of sound radiation(DSR) and acoustical converting efficiency(ACE) decreased by oriental lacquering and cashew varnishing for both species. Damping of internal friction of chestnut decreased by oriental lacquering and cashew varnishing, but that of paulownia increased. Natural frequency. specific Young's modulus, acoustical coefficient, sound velocity, and DSR decreased with increased film thickness of both finishing materials. However, damping of internal friction and ACE showed irregular tendency with increased film thickness. Acoustical properties of cashew varnished chestnut specimen were better than those of oriental lacquered specimen. Acoustical properties of oriental lacquered paulownia specimen were better than those of cashew varnished specimen.

• International Journal of Fluid Machinery and Systems
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• 제2권1호
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• pp.80-91
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• 2009

In this study, a prediction theory for specific noise that is the overall characteristic of the fan has been proposed. This theory is based on total pressure prediction and broadband noise prediction. The specific noises of two forward curved fans with different number of blades were predicted. The flow around the impeller having 120 blades (MF120) was more biased at a certain positions than the impeller with 40 blades (MF40). An effective domain of the energy conversion of MF40 has extended overall than MF120. The total pressure was affected by the slip factor and pressure loss caused by the vortex flow. The suppression of a major pressure drop by the vortex flow and expansion of the effective domain for energy conversion contributed to an increase in the total pressure of MF40 at the design point. The position of maximum relative velocity was different for each fan. The relative velocity of MF120 was less than that of MF40 due to the deviation angle. The specific noise of MF120 was 2.7 dB less than that of MF40 due to the difference in internal flow. It has been quantitatively estimated that the deceleration in the relative velocity contributed to the improvement in the overall performance.

• Journal of Acupuncture Research
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• 제21권3호
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• pp.83-97
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• 2004

Objective : This study was performed to evaluate the effect acupuncture on cerebral blood flow by Transcranial Doppler Ultrasonography(TCD). Methods : Monitoring of TCD was examined in stroke patients before and after acupuncture on seven points of CVA. Mean Velocity, pulsatility index, systolic velocity, diastolic velocity values are analyzed from TCD at middle cerebral artery. Results : The results showed a insignificant(p>0.05: Paired T-test) decrease in mean velocity, pulsatility index, systolic velocity, diastolic velocity, which was measured at normal middle cerebral artery. The results showed a significant($p{\leq}0.05$: Paired T-test) decrease in mean velocity, pulsatility index, systolic velocity, which was measured at injuried middle cerebral artery, except diastolic velocity. Conclusion : These results suggest that acupuncture could have a specific effect on injuried cerebral artery.

• 한국물환경학회지
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• 제29권4호
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• pp.551-558
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• 2013

The feasibility of water supply as in-stream flow for Mangwall stream was analyzed in terms of water quality and cultivation periphyton using two different types of water resources (e.g., surface water and bank filtration from Han River basin) and three different types of media (e.g., tile, concrete and pebble). The concentrations of organic and inorganic contaminants from the bank filtration were lower than those from surface water by 17.5 - 55.0%. Using water samples collected from Mangwall stream, surface water, and bank filtration, chlorophyll-a, phaeopigment, and growth rate of periphyton were investigated. During 30 day incubation for each water sample, it was observed that filamentous cyanobacteria, Oscillatoriaceae, accounted for 98%, and water velocity of 5 cm/s was optimum for the in situ filamentous cyanobacteria growth. Also, it was deducted for water velocity and chl-a to have an inverse correlation. Meanwhile, the greater the specific surface area of media, the higher the concentration of chl-a. From these results, both water velocity and specific surface area of media should be considered as an combined parameter to deter the growth of filamentous cyanobacteria.