• Wind and Structures
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• 제20권4호
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• pp.509-525
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• 2015

A three-dimensional aerodynamic model and a vehicle dynamics model are established to investigate the effect of noise barrier on the dynamic performance of a high-speed train running on an embankment in crosswind in this paper. Based on the developed model, flow structures around the train with and without noise barrier are compared. Effect of the noise barrier height on the train dynamic performance is studied. Then, comparisons between the dynamic performance indexes of the train running on the windward track and on the leeward track are made. The calculated results show that the noise barrier has significant effects on the structure of the flow field around the train in crosswind and thus on the dynamic performance of the high-speed train. The dynamic performance of the train on the windward track is better than that on the leeward track. In addition, various heights of the noise barrier will have different effects on the train dynamic performance. The dynamic performance indexes keep decreasing with the increase of the noise barrier height before the height reaches a certain value, while these indexes have an inverse trend when the height is above this value. These results suggest that optimization on the noise barrier height is possible and demonstrate that the designed noise barrier height of the existing China Railway High-speed line analysed in this article is reasonable from the view point of the flow field structure and train dynamic performance although the noise barrier is always designed based on the noise-related standard.

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.31-34
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• 2006

The experiment was conducted to determine the effects of cutting interval and cutting height on the yield and nutrient composition of hedge lucerne (Desmanthus virgatus) when grown on a sandy soil in the Northeast of Thailand. The cutting intervals compared were 30, 40 and 50 days between harvests and the cutting heights 30, 40 and 50 cm above ground level. The experiment was a $3{\times}3$ factorial layout in a randomized complete block design with 4 replications-giving a total of 36 plots each $3{\times}3m^2$. Harvested plant material was weighed, dried and the ground subsamples taken for analyses of crude protein (CP), crude fiber (CF), ash, ether extract (EE) and nitrogen-free extract (NFE). At the last harvest the hedge lucerne samples were separated to determine leaf to stem ratios and then analyzed for nutrient composition in the leaf and stem. Results showed that increasing the cutting interval (i.e. advancing age of maturity) increased dry matter and nutrient yields significantly. In terms of nutrient content, it also increased the crude fiber, ash, ether extract and nitrogen free extract percent in the plant. However, crude protein percent was markedly decreased as the cutting interval increased. Increasing cutting height had no effect on dry matter yield and yields of nutrients, but in terms of nutrient content, it increased crude protein and ash content, but decreased crude fiber content. The percent EE and NFE in the plant was unaffected by cutting height. From the results presented it is clear that cutting a stand of hedge lucerne every 40 to 50 days will achieve greater dry matter and nutrient yields than cutting more frequently, at 30 days. The cutting height at harvest, whether 30, 40 or 50 cm above ground level had no effect on dry matter or nutrient yields of hedge Lucerne. Hedge lucerne therefore offers the Thai poultry farmer a useful alternative protein supplement for poultry diets rather than relying on the more expensive soybean meal. As it can be readily and successfully grown on a range of soil types and climates throughout Thailand, hedge lucerne also offers the Thai farmer a valuable additional source of income.

• Korean Chemical Engineering Research
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• 제57권1호
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• pp.105-110
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• 2019

CNT 유동층 반응기(내경 0.15 m, 높이 2.6 m) 프리보드 내 미세 CNT 입자(평균입도 $46{\mu}m$, 벌크밀도 $93.2kg/m^3$)의 높이 별 거동을 확인하기 위해 레이저 슬릿광 형상 측정법을 이용하여, CNT 응집체의 크기 및 형태를 측정하였다. 기체 유속 증가에 대해, 비산되는 CNT 응집체의 Feret 직경과 Heywood 직경이 증가하였다. 프리보드 내 높이가 증가할수록 평균 직경은 작아졌고, 응집체 내 CNT 입자수가 감소하였다. 기체 유속 증가에 대해, 응집체의 종횡비는 농후상에 가까울수록 증가하였으나, 높은 높이에서는 감소하였다. 그러나, 견고도는 큰 변화를 보이지 않았다. 응집체의 형상 분석 정보에 기반하여, 높이 별 CNT 입자의 응집과정이 서로 다름을 확인하였다. 유동층 프리보드 내 CNT 응집체의 Heywood 직경을 예측할 수 있는 상관관계식을 제안하였다.

• 한국해안·해양공학회논문집
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• 제32권4호
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• pp.223-229
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• 2020

시간차를 지닌 단층파괴 활동은 지진해일의 초기파형 생성에 영향을 끼치며, 이로 인해 해안에서의 처오름 높이에도 변화를 준다. 이러한 단층파괴 활동이 처오름 높이에 미치는 영향을 검토하기 위하여 일본 서해역에 다수의 가상 단층파괴를 가정하여 수치모의를 수행하였다. 소단층들이 해안선에 평행하게 위치한 경우에는 시간차를 지닌 단층파괴가 처오름 높이에 미치는 영향은 미미했으나, 해안선에 수직으로 위치해 있는 경우에는 초기파형의 중첩효과가 두드러지게 발생하여 해안선에서 처오름 높이가 증가하였다.

• 한국운동역학회지
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• 제20권2호
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• pp.129-137
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• 2010

The purpose of this study is to investigate the effect of a 12-week aquatic exercise on obstacle gait in older women. Originally, 20 healthy female elderly participated this study but 12 of them completed the program. All participants were trained in the aquatic exercise program by an authorized trainer. They had come to the authors' lab three times during training period(0, 6, 12 weeks) and performed obstacle gait with three different height(0, 30, and 50% of leg length). After performed 3-Dimensional motion analysis following results were found. (1) For the CV, MVHC, TC, HC, statistically significances were shown in obstacle height. Although significant training effects were not shown, all variables showed typical patterns and it was considered as efficient motion to overcome the height obstacles. (2) The anterior-posterior and vertical GRF of support leg during support phase were revealed in height effect but in training one. However, differences between Peak 1 and Peak 2 in vertical GRF increased as training period increased. (3) Knee and hip resultant joint moments were affected by training but ankle resultant moments remained unchanged.

• 국제물리치료학회지
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• 제9권1호
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• pp.1420-1425
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• 2018

The purpose of this study was to investigate the effect of traction and decompression therapies on the cervical muscle tone and disc height. The decompression group (n=16) received decompression therapy and Mckenzie exercises once a day and four times a week respectively, for three weeks. The traction group (n=15) also received traction therapy and Mckenzie exercises for the same period. Muscle tone was measured with a myotonometer, and the disk height was measured using magnetic resonance imaging (MRI), before the interventions. Three weeks later, we investigated the therapeutic effect by repeating these measurements. The difference in disk height between the two groups was not significant. There was a significant difference in the disk herniation index (p<.05). A significant difference was found only in the upper trapezius muscle after comparison of muscle tone and stiffness between the groups (p<.05). Findings from this study suggest that the decompression therapy is a more effective intervention for patients with cervical intervertebral disc herniation.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 춘계학술대회 논문집
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• pp.439-446
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• 2000

본 연구에서는 절점당 7자유도(뒤틀림 자유도 포함)를 갖는 보요소를 개발하여, 와그너 효과(Wagner Effect) 및 하중고 효과(Load Height Effect)가 일축 대칭 I 형보의 횡좌굴 강도에 미치는 영향을 파악하였다. 하중의 종류는 단면내 다양한 높이에 작용하는 횡방향 하중과 선형 모멘트 구배하중을 고려하였으며, 이들 하중에 의한 비지지 길이내 단일곡률의 휨과 역의 곡률의 휨이 생길때의 좌굴해석을 수행하였다. 현행 LRFD $C_{b}$ 계수의 일축 대칭 I 형 보에의 적용성을 검토하였으며, 하중고 효과(Load height effect) 및 비지지 길이내 역의 곡률(Reverse curvature bending) 발생시에 생기는 문제점들을 고찰해 보고, 해결방안을 제시하였다.

• 동력기계공학회지
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• 제18권6호
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• pp.207-214
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• 2014

Mass and flow resistance in a square ribbed microchannel have been studied numerically using the Lattice Boltzmann Method. It has been build up on two dimensional nine velocity vectors model with single relaxation time method called the Lattice Bhatnagor-Gross-Krook model. To analyze the roughness effect on the flow resistance namely the friction factor and mass flow has been discussed at the slip flow regime, $0.01{\leq}Kn{\leq}0.10$, where Kn is the Knudsen number. The wall roughness is considered by square microelements with a relative roughness height up to maximum 10% of channel height. The velocity profiles in terms of streamlines near the riblets are demonstrated to be responsible for the roughness effect. It is found that the roughness effect leads to increase the flow resistance with roughness height but it is decreased significantly with increasing the space between two roughness elements as well as the Knudsen number. In addition, the mass flow decreased linearly with increasing both roughness height and gap but significantly changed at the slip flow regime.

• 한국연소학회지
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• 제17권1호
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• pp.48-57
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• 2012

Laminar lifted propane coflow-jet flames diluted with nitrogen were experimentally investigated to determine heat-loss-related self-excitation regimes in the flame stability map and elucidate the individual flame characteristics. There exists a critical lift-off height over which flame-stabilizing effect becomes minor, thereby causing a normal heat-loss-induced self-excitation with O(0.01 Hz). Air-coflowing can suppress the normal heat-loss-induced self-excitation through increase of a Peclet number; meanwhile it can enhance the normal heat-lossinduced self-excitation through reducing fuel concentration gradient and thereby decreasing the reaction rate of trailing diffusion flame. Below the critical lift-off height. the effect of flame stabilization is superior, leading to a coflow-modulated heat-loss-induced self-excitation with O(0.001 Hz). Over the critical lift-off height, the effect of reducing fuel concentration gradient is pronounced, so that the normal heat-loss-induced self-excitation is restored. A newly found prompt self-excitation, observed prior to a heat-loss-induced flame blowout, is discussed. Heat-loss-related self-excitations, obtained laminar lifted propane coflow-jet flames diluted with nitrogen, were characterized by the functional dependency of Strouhal number on related parameters. The critical lift-off height was also reasonably characterized by Peclet number and fuel mole fraction.

• 대한한의학회지
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• 제23권3호
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• pp.1-10
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• 2002

Objective: There exist gender differences in pulsatile contour waveform. Women have a greater age-related increase in left ventricular mass than do men and more likely to experience symptomatic heart failure after infarction. SDPTG (the second derivative of photoplethysmogram waveform) is a noninvasive method for evaluating the pulse wave and is correlated with age and other risk factors for atherosclerosis. We studied the effect of gender on SDPTG and made clear why the gender differences appear. Methods: To study the effects of effect factors, including height and blood pressure, on SDPTG in the fourth decade, data on height, weight, PTD (pulse transit distance), blood pressure, serum lipid levels, and SDPTG were collected in 115 laboratory healthy men and women. SDPTG is derived from double-differential processing of fingertip photoplethysmography and consists of a, b, c, and d waves in systole and an e wave in diastole; SDPTG aging index (AI) was calculated as (b-c-d-e)/a. Results: There were significant gender-related differences of SDPTG AI, height, and blood pressure. Age, height, and mean blood pressure were respectively and significantly correlated with SDPTG AI. SDPTG is dependent upon age, height, and blood pressure. Restricting analysis to SDPTG AI, age, height, and mean blood pressure, yielded that there were gender-related differences in SDPTG AI (P<0.05) which were derived from those of height (F<0.001, df=l, P=0.994). Conclusions: These new data may help to explain previous findings about age-related differences in pulsatile contour waveforms and why gender differences of SDPTG appear. The results of this study suggest that SDPTG AI, used for evaluation of biological vascular aging, should be calibrated by height as well as age and blood pressure.