• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2325-2334
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• 2023

To study the lubrication performance of tilting-pad thrust bearing (TPTBs) during start-up in nuclear pump, a hydrodynamic lubrication model of TPTBs was established based on the computational fluid dynamics (CFD) method and the fluid-structure interaction (FSI) technique. Further, a mesh motion algorithm for the transient calculation of thrust bearings was developed based on the user defined function (UDF). The result demonstrated that minimum film thickness increases first and then decreases with the rotational speed under start-up condition. The influence of pad tilt on minimum film thickness is greater than that of collar movement at low speed, and the establishment of dynamic pressure mainly depends on pad tilt and minimum film thickness increases. As the increase of rotational speed, the influence of pad tilt was abated, where the influence of the moving of the collar dominated gradually, and minimum film thickness decreases. For TPTBs, the circumferential angle of the pad is always greater than the radial angle. When the rotational speed is constant, the change rate of radial angle is greater than that of circumferential angle with the increase of loading forces. This study can provide reference for improving bearing wear resistance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1892-1894
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• 2004

We have suggested the moxa-pad cauterizer especially for knee arthralgia. We have researched the variation on knee heat generating by the moxa-pad moxibustion cauterizer. The experimental demonstrations have been made by the stimulating the spots which are G-34(Gall-bladder Meridian 34), Sp-9(Spleen Meridian 9), and Liv-3(Liver Meridian 3) acupuncture points. And stimulating time was one hour with moxa-pad cauterizer.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.235-240
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• 1998

The inlet pressure build-up at the leading edge of bearings and its effects on the static performances are investigated theoretically. The performance analyses of air-lubricated tilting pad bearings are carried out considering the inlet pressure which is obtained by means of momentum conservation method. The results show that inlet pressure is above atmosphere pressure in front of leading edge of tilting pad bearing and there is a significant influence of the inlet pressure on the performance of bearings.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.311-318
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• 2000

In this paper, the process of development of resilient sleepers, which improves the train safety, passenger comport and reduces the noise and vibration, is discussed. To determine the required material properties of elastic pad, static and dynamic simulations are performed and is applied in manufacturing. From the experiment results, it is investigated that the displacement is less for sleeper with elastic pad than that in ordinary PC form. The rate of displacement is also shown In be less for the sleeper with elastic pad. These results indicate that the elastic pad can reduce possibility of rail-corrugations and thus resulting in the reduction of maintenance costs.

• 대한전자공학회논문지
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• 제25권3호
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• pp.302-307
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• 1988

A noble interconnection line capacitance measurement method to be able to remove the measurement errors from the probe pad to substrate stray capacitance has been proposed and verified. The measurement errors in the capacitance measurement, which usually be involved from the probe pad to substrate stray capacitance, can easily be removed by isolating the metal probe pad from the substrate with a grounded shield plate between the probe pad the substrate. The measurement results by using this improved capacitance measurement method were compared with the calculations by two-dimensional computer simulations.

• Tribology and Lubricants
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• 제17권2호
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• pp.116-123
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• 2001

A theoretical analysis has been undertaken to show the influence of bearing geometry on the steady state characteristics of air lubricated spherical tilting pad bearings. The geometry variations considered are the number of pads, the eccentricity ratio, the direction of load, and the preloading. Dynamic characteristic equations are derived with pad assembly method.

• Journal of Preventive Medicine and Public Health
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• 제28권2호
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• pp.364-372
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• 1995

말초동맥질환 유병률을 조사하기 위하여 경상북도 경산군 남산면과 진량면 53개 리의 65세 이상 노인 803명을 방문 면담 조사하였다. 조사 도구로는 Edinburgh 파행 설문지를 이용하였다. 더불어, 성별, 연령, 흡연 습관에 관하여 질문하고, 신장과 체중을 측정하여 체질량 지수로 치환하고, 혈압을 측정하였다. 말초동맥질환의 유병률은 9.0%이며 남자는 8.5%, 여자는 9.3%로 성별에 따른 유의한 차이는 없었다. 그리고, 전형적 파행은 3.9%이고, 비전형적 파행은 5.1%이고 증상의 정도를 보면 1도는 4.4%, 2도는 4.6%이었다. 연령에 따른 말초동맥질환의 유병률을 보면 $65\sim69$세는 7.7%, $70\sim74$세는 9.5%, $75\sim79$세는 9.7%, 80세 이상은 9.8%로 연령에 따라 증가하는 경향은 있으나 통계학적 유의성은 없었다. 말초동맥질환의 유병률은 수축기 혈압이 160mmHg 이상군에서는 18.9%로 160mmHg 미만군의 7.9%보다 유의하게 높았고(p<0.05), 체질량 지수가 20미만군에서는 15.1%이고, $20\sim25$ 미만군에서는 10.3%, 25 이상의 비만군에서는 2.8%로 체질량 지수가 증가함에 따라 유병률은 유의하게 감소하였다(p<0.05). 흡연군에서는 8.8%, 비흡연군은 9.0%로 흡연에 따른 말초동맥질환의 유병률의 유의한 차이는 없었다. 따라서 우리나라 농촌지역 노인들에서의 말초동맥 질환의 유병률이 9.0%로 말초동맥질환이 우리나라에서도 중요한 노인보건문제로 추후 이에 대한 연구가 더 필요하다고 생각된다.

• 한국의류학회지
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• 제15권2호
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• pp.139-150
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• 1991

The purpose of this study is to do the Somatotype classification according to the type of shoulder-neck and to give the thinkness of shoulder pad according to them. Therefore this study was measurement body size of 201 and the somatotypes were classified as their plumb line. The standard somatotype of this measurement was classified as 9 type according to its angle of shoulder inclination and neck length. Pads which have different thickness (1 cm, 1.5 cm, 2 cm) were attached to the 9 body type and the set-in sleeve blouse and raglan sleeve blouse were made and tring test and sensory test were accomplished. The results of this study were as follows: 1 . Classification of shoulder-neck relationship. Angles of shoulder inclination ($15^{\circ},\;21^{\circ},\;27^{\circ}$), lock lenaths (10 cm, 12.5 cm, 15 cm) were classi- fied as 3 type each and these types were combined as 9 types. II . The result of angle difference of shoulder inclination according to pad thickness. 1) In case of set-in pad. angle is increased $5.75^{\circ}$ per 1 cm of pad thickness. 2) In case of raglan pad. angle is increased $6.45^{\circ}$ per 1 cm of pad thickness. III. The most fit pad thickness to the 9 types. In case of set-in sleeve blouse. 1) High shoulder-long neck, Standard shoulder-long neck Low shoulder-long neck, Stan-dard shoulder·standard neck. Low shoulder-standard neck: 1.5 cm. 2) High shoulder-standard neck, Standard shoulder-short neck, Low shoulder-short neck: 1 cm. 3) High shoulder-short neck: 0 cm(without pad) In case of raglan sleeve blouse. 4) High shoulder-long neck, Standard shoulder-long neck, Low shoulder·long neck, Stan-dard shoulder-standard neck, Low shoulder-standard neck: 1.5 cm. 5) High shoulder-standard neck, Standard shoulder-short neck, Low-shoulder-short neck: 1 cm. 6) High shoulder-short neck: 0 cm(without pad)

• Tribology and Lubricants
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• 제33권3호
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• pp.85-91
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• 2017

This work studies the flow behaviors in the gap between the friction pad and separator in wet-clutch systems. The fluid volume of the lubricant is modeled using the entire system of wet-clutch pack of a dual clutch transmission that has larger outer radius of odd gear shifts and smaller inner radius of even gear shifts. Flow behaviors in the gap of the clutch pad are computed using the gear shift modes that consider the real relative velocities between the friction pad and separator. Flow behaviors in the gap of the disengaged clutch pad are mainly investigated for the wet-clutch system, whereas the engaged clutch pad is modeled with no fluid rate through the contacting surfaces. The developed hydrodynamic fluid pressures and velocity fields in the clutch pad gap are computed to obtain the relevant information for managing flow rates in wet-clutch packs under dual operating conditions during gear shifts. These hydrodynamic pressures and velocity fields are compared on the basis of each gear level and gap location, which is necessary to determine the effects of groove patterns on the friction pad. Shear stresses in the gap locations are also computed on the basis of the gear level for the inner and outer clutch pads. The computed results are compared and used for the design of cooling capacity against frictional heat generation in wet-clutch pack systems.

• Tribology and Lubricants
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• 제36권1호
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• pp.27-33
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• 2020

Self-equalizing tilting pad thrust bearings are usually employed in turbomachines to achieve high stability and reliability. A tilting pad bearing can incorporate self-equalizing links to handle the misalignment between the bearing and the thrust collar. In this popular design method, the pads sit on the upper-level plates and the lower-level plates stay on the retainer base. With misalignment, the pads that are heavily loaded are pushed down. Consequently, the link pushes up the pads on the opposite side, keeping the bearing surface parallel to the thrust collar surface. The self-equalizing link is used to handle the misalignment from the thermal and mechanical effects. In this study, the experimental investigation deals with the performance of self-equalizing tilting pad thrust bearings. The test rig for evaluating the performance of bearing is developed which can control the misalignment angle. Simultaneous measurements are taken for the force acting on each pad. Pad metal temperature and oil film thickness are functions of the shaft speed, bearing load, misalignment angle, and design of leveling plates. The effect of misalignment on bearing performance is discussed. The results demonstrate that the load on each pad depends on the test conditions(especially misalignment angle), and the load influences the performance of bearings.