• 대한기계학회논문집
• /
• 제19권9호
• /
• pp.2365-2372
• /
• 1995

The objective of this study is to get the basic data for the development of fluidized bed combustor. For this purpose, various rake angles(.theta.=20.deg., 25.deg., 30.deg., 35.deg.) of finned tubes and a smooth tube were installed horizontally in the fluidized bed combustor of 410*250mm. The effect of fluidized bed temperature, superficial velocity in bed, size of bed materials, rake angle of finned tubes on the heat transfer coefficient was experimentally investigated. The following results were obtained. (1) Under the fluidized bed temperature(750.deg. C-900.deg. C), and the gas velocity in bed(1.1-2.8m/sec), The highest heat transfer coefficient was measured with the rake angle of finned tubes was .theta.=25.deg. and .theta.=35.deg. for the average fluidized material particle size of 1.22mm and 1.54mm, respectively. Generally, the heat transfer coefficient of finned tubes is 1.4 to 2.4 times larger than that of smooth tubes. (2) The size of bed materials influences the rake angle of finned tubes which can have the highest heat transfer coefficient. As the temperature in bed gets higher, the effect of the rake angle of finned tubes on the heat transfer coefficient becomes greater.

• 임상간호연구
• /
• 제23권3호
• /
• pp.293-301
• /
• 2017

Purpose: The purpose of this study was to examine the effects of bed angles and bed rest time combined with hemostatic methods on discomfort and hemorrhagic complications in patients after transfemoral cerebral angiography. Methods: Data were collected from 93 inpatients following transfemoral cerebral angiography, from April 20 to September 23, 2016. Patients were grouped according to bed angle ($0^{\circ}$ vs. $30^{\circ}$) and bed rest time combined with hemostatic methods (4-hour bed rest after manual compression vs. 2-hour bed rest after applying vascular closure device). Results: There was a significant group differences on discomfort (F=46.44, p<.001). The post-hoc analysis showed the lowest score of discomfort in those with bed angle $30^{\circ}$ and 2-hour bed rest. There was no difference in hemorrhagic complications among 4 groups. Conclusion: The postangiograpy discomfort can be effectively reduced with the least hemorrhagic complications by bed angle $30^{\circ}$ elevation and 2-hour bed rest after applying vascular closure device for those underwent transfemoral cerebral angiography.

• 한국연소학회지
• /
• 제1권1호
• /
• pp.19-29
• /
• 1996

This study is to investigate the characteristics of heat transfer of a horizontal tube, with radial fins of various configuration, immersed in a high temperature fluidized bed. The experimental heat transfer variation is compared with that of a smooth tube. The finned tubes and smooth tube, with outside and inside diameter of 48.6mm and 30.6mm, are made of steel tubes. The depth of the fin is 5mm, the rake angles of fin are $25^{\circ},\;35^{\circ},\;45^{\circ}$ and the widthes of fin for each rake angle are 0mm, 1mm, 2mm and 3mm. A bed temperature is fixed at $880\;{\pm}\;10^{\circ}C$. A granular refractory(silica sand) is used as a bed material with mean particle diameters of 1.22mm and 1.54mm. The maximum heat transfer coefficient is achieved with the rake angle of $25^{\circ}$ and the width of 0mm for the mean particle size 1.22mm. The coefficient is 2.14 times larger than that for a smooth tube. The rake angle for the maximum heat transfer coefficient depends on the particle size of bed material. Also the transfer coefficient decreases as the width of fin increases.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.944-947
• /
• 2004

The purpose of this study was to identify the characteristics of muscular power by COP(center of pressure) training according to the angle variation of tilting bed. We changed the angles of tilting bed(up-down direction 0$^{\circ}$, 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$ and right-left direction -15$^{\circ}$, 0$^{\circ}$, +15$^{\circ}$) for the correlation between angles and muscular power. And we measured EMG(electormyography) of lower limbs muscle(rectus femoris, biceps femoris, and gastrocnemius, tibialisa anterior) during COP training. COP training was divided by the COP trace training(in all direction) and sine wave trace training(vertical and horizontal direction). As the result, we obtained the improvement effect of COP training and we showed that electromyography(EMG) variations of lower limbs muscle on the angle variations of tilting bed were investigated.

• 정형스포츠물리치료학회지
• /
• 제14권2호
• /
• pp.127-133
• /
• 2018

Purpose: This study investigated the effects of changing the tilt angle of the exercise bed on physiological characteristics of trapezius, multifidus, and hamstring muscle function. Methods: Twenty elderly who complains of back and lumbar pain or discomfort participated in this study (average age: $64.70{\pm}4.55$ years). The physiological characteristics, including muscle tone (F), dynamic stiffness (S), and elasticity (D) of trapezius, multifidus, and hamstring muscles were measured by a Myoton device at three tilt angles (0, 15, and 30 degrees) during exercise. Results: The muscle tone, dynamic stiffness, and elasticity of the right trapezius and left hamstring muscle showed significant differences (p<0.05) according to exercise bed tilt angle, while the other muscles showed no significant differences. Conclusions: Our results demonstrate that physiological characteristics of the upper and lower extremity muscles are affected ipsilaterally, according to the tilt angles of the exercise bed.

• 제어로봇시스템학회논문지
• /
• 제21권11호
• /
• pp.1038-1043
• /
• 2015

When the study on the relationship between the Head-of-Bed (HOB) angle and ventilator-associated pneumonia is performed, the fact that the HOB angle can only be measured intermittently imposes a significant limitation on the study. Therefore, there has been demand for the development of a device that can measure the HOB angle continuously. In this paper, we propose the rapid prototyping of an HOB measurement system using open-source hardware and software. The proposed system helps to maintain the HOB angle at a particular angle by displaying the angle and helps the medical study of pneumonia patients by enabling continuous data acquisition. Firstly, we eliminate the process of making an MCU board by utilizing an open-source hardware mbed LPC1768. Secondly, we reduce the software development time by using libraries and hence enabling the easy use of peripherals. Thirdly, for rapid prototyping, we build the enclosure of the proposed system using a 3D printer. The proposed system can be attached and detached to and from a bed. Therefore, we can attach it to the bed of a patient for whom measurement of the HOB angle is necessary. Finally, we check the measurement performance and the validity of the proposed system through an experiment utilizing an incremental encoder.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
• /
• pp.24-32
• /
• 2004

The characteristics of heat transfer from horizontal cylinder immersed in both a riser and downcomer of a circulating fluidized beds were investigated experimentally under different values of solids mass flux, superficial air velocity, particle size diameter, and different bed materials. The test results indicated that local heat transfer coefficients in both riser and downcomer are strongly influenced by angular position, and mass flux, as well as by particle size and bed materials. The local heat transfer coefficients around a circumference of the cylinder inside a riser and downcomer of a CFB exhibited a general tendency to increase with decreasing particle size and increasing solids mass flux and vary with different bed materials. Also the averaged heat transfer coefficient calculated from local heat transfer coefficient exhibited the same trend as a local i.e increase with decrease particle size and increasing solids mass flux and vary with varying bed materials. The general trend for a riser local heat transfer coefficient is decrease with increase angle until ${\Phi}$ = 0.5-0.6 (Where at angle =180$^{\circ}$ ${\Phi}$ =1). Also the general trend for a local heat transfer coefficient in downcomer is to increase with increase the angle until ${\Phi}$= ${\theta}/{\Pi}$ = 0.3-0.5 (Where at angle =180$^{\circ}$ ${\Phi}$ =1). Comparison the results of the heat transfer in the riser and downcomer of a circulating fluidized beds shows that they have approximately the same trend but the values of heat transfer coefficients in riser is higher than in downcomer.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2002년도 학술대회지
• /
• pp.95-98
• /
• 2002

Three-dimensional flow analyses for two different ratios of radius to height of sedimentation bed are implemented to evaluate the effect of blockage ratio of center feed wall and angle of distributor on sedimentation efficiency, and to find the optimal value of those parameters. Sedimentation efficiencies for three different shapes are compared with and without rotation speed. And then, five different combinations of blockage ratio of center feed wall and angle of distributor are compared It reveals that the effect of blockage ratio of center fled wall and angle of distributor is considerable to sedimentation efficiency while rotation effect can be neglected and $0.55 and 33^{\circ}$for blockage ratio of center food wall and angle of distributor, respectively, ive the best sedimentation efficiency.

• 한국수자원학회논문집
• /
• 제31권3호
• /
• pp.291-301
• /
• 1998

본 연구에서는 치수 및 이수에 있어서 항상 어려움을 겪고 있는 개수로 만곡구간에서 하상재료의 변화에 따른 흐름 및 하상변동 특성을 분석하기 위하여 중심각 180'인 만곡수로를 제작하고, 모래(D50 = 0.26 MM, S = 1.54)와 안트라싸이트(D50 = 0.26 mm, S = 1.54)를 하상재료로 선택하여 실험을 실시하였다. 실험결과, 최대세굴심은 만곡각 30'-60' 외측제방부근에서 평균수심의 약 2배까지 실측되었으며, 최대세굴심의 발생위치는 안트라싸이트인 경우에 모래에서보다 5'-15' 정도 상류부에서 관측되었다. 종단면 최대유속선은 하상재료와 관계없이 내측에서 외측으로 편의되고 있으며, 하상이 거칠수록 하류로 이동하였다. 하상이 매끄러울수록 흐름의 최대 편의각은 만곡수로 상류부에서 발생하고 있으며, 그 크기도 증가하였다. 안트라싸이트의 경우가 모래의 경우보다 2차흐름이 크게 발생하는 것으로 실측되었으며, 두개의 핵이 존재하는 현상이 관측되었다.

• 한국유체기계학회 논문집
• /
• 제6권2호
• /
• pp.54-61
• /
• 2003

Both numerical and experimental studies on the sedimentation efficiency of a sedimentation bed were carried out. Three different structures of sedimentation bed and five different combinations of blockage ratio of center feed wall and angle of distributor are implemented to find the optimal values of geometric parameters. The effect of rotation of the distributor on sedimentation efficiency is also investigated. It reveals that the effects of blockage ratio and angle of distributor on sedimentation efficiency are considerable, while rotation effect can be neglected, and that calculated efficiencies show good agreements with those of experiment, qualitatively.