• Geomechanics and Engineering
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• v.12 no.6
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• pp.1021-1046
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• 2017

The assessment of slope stability is an essential task in geotechnical engineering. In this paper, a three-dimensional (3D) finite element analysis (FEA) was employed to investigate the performance of different shear pin arrangements to increase the stability of a soil block resting on an inclined plane with a low-interface friction plane. In the numerical models, the soil block was modeled by volume elements with linear elastic perfectly plastic material in a drained condition, while the shear pins were modeled by volume elements with linear elastic material. Interface elements were used along the bedding plane (bedding interface element) and around the shear pins (shear pin interface element) to simulate the soil-structure interaction. Bedding interface elements were used to capture the shear sliding of the soil on the low-interface friction plane while shear pin interface elements were used to model the shear bonding of the soil around the pins. A failure analysis was performed by means of the gravity loading method. The results of the 3D FEA with the numerical models were compared to those with the physical models for all cases. The effects of the number of shear pins, the shear pin locations, the different shear pin arrangements, the thickness and the width of the soil block and the associated failure mechanisms were discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.294-304
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• 2003

An experimental analysis using three-dimensional laser Doppler velocimetry(LDV) measurement and computational analysis using the Reynolds stress model in FLUENT are conducted to give a clear understanding of the effect of blade loading on the structure of tip leakage flow in a forward-swept axial-flow fan operating at the maximum efficiency condition ($\Phi$=0.25) and two off-design conditions ($\Phi$=0.21 and 0.30). As the blade loading increases, the onset position of the rolling-up of tip leakage flow moves upstream and the trajectory of tip leakage vortex center is more inclined toward the circumferential direction. Because the casing boundary layer becomes thicker and the mixing between the through-flow and the leakage jet with the different flow direction is enforced, the streamwise vorticity decays more fast with the blade loading increasing. A distinct tip leakage vortex is observed downstream of the blade trailing edge at $\Phi$=0.30, but it is not observed at $\Phi$=0.21 and 0.25.

• Explosives and Blasting
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• v.24 no.1
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• pp.1-8
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• 2006

Recently, most of limestone quarries have been not mined by open-pit mining but by underground excavation to reduce environmental pollution. As a result, the size of underground galleries became bigger to maintain mass-production close to open-pit mining. However, the scale of pillars and galleries as well as the excavation methods may induce a few adverse problems for the stability of a mined gallery. In this study, the nomogram analysis and the prediction of rock damage zone induced by blasting were carried out. The testing conditions include concurrent blasting of two adjacent galleries, concurrent blasting of a transport drift and a inclined shaft, sequential blasting of two galleries, and separate blasting for each gallery. For each testing condition, blast vibration velocity was measured and analyzed. From the prediction formulas for blast vibration velocity derived in this study, the maximum depth of rock damage zone induced by blasting were also predicted.

• The Korean Journal of Emergency Medical Services
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• v.5 no.1
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• pp.109-131
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• 2001

1. In general, male-to-female rate of those investigated was 1.83:1(M:F) and in term of economic status, most were middle class. The investigation shows that reserved, sharp and nervous persons were inclined to easily fall ill. 2. The probability of their falling ill was high in the fall and during sleep because probability of cerebral infarction was high. 3. It was found that they more refained from overeating and from eating pungent food and had less meat than before illness, in addition that refaining from drinking and smoking further improves their daily lives. 4. The especially acknowledged the necessity of physical exercise, they exercised, more frequency, but less strenuously. This was due to the decline in their physical strength or the unsystematic nature of the exercise. 5. In terms of weight loss, the test subjects lost 5kg on average while two of them lost 10kg. The investigation revealed that such stroke patients could overcome a range of problems, and they could improve and maintain their daily condition through guidance and education about their illness. Furthermore, it was revealed that patients needed be shown love and concern, to lead a normal satisfying social life.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.80-84
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• 1996

This paper aims at reviewing the Possibility application over normal or abnormal, detection used by AE and the wear characteristics of grinding process. In this study, when diamond bur in dentistry with chosen grinding conditions were tuned at grinding. The variation of grinding resistance and hE signal is detected by the use of AE measuring system. The tests are carried out in accordance with diamond burs and workpiece; arcyl and bovine. According to the experiment results, the following can be expected; AE has the possibility to detect the state normality and abnormality. However, the grinding resistance measuring can find it difficult to detect it. It can be accurately excerpted from AE occurrence pattern in contact start point of diamond bur and bovine, grinding condition and derailment point. It is known that AE$\_$rms/ is well compatible with grinding resistance. According to the increase of the material removal rate, the specific energy of the diamond bur is inclined to decrease and the grinding resistance has a tendency to increase.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.1
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• pp.1-6
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• 2016

The effect of reducing wave overtopping by use of the wave return wall was quantitatively analyzed based on physical experiments. The overtopping discharge for the arc seawall and the inclined seawall was measured and compared with the predictive formula that estimates reduction of overtopping by the wave return wall. When the overtopping discharge was relatively large ($q/{\sqrt{gH^3_s}}>10^{-3}$), the agreement in terms of overtopping reduction rate was fairly good between the prediction and the measurement. For the condition of smaller overtopping than the above criterion, however, the discrepancy was large between the predicted and measured result. In this context, it is required to develop a better formula for estimating reduction of wave overtopping by the wave return wall.

• Hwankyungkyoyuk
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• v.24 no.1
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• pp.26-39
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• 2011

The purpose of this study is to review the current state of energy education in Korea and identifies barriers faced by teachers in doing energy education. For this purpose, this study carried out a questionnaire survey targeting energy saving policy research-schools. The results of this research are as follows. First, teachers facing barriers in energy education pointed out the lack of teaching text and students' interest in energy, and work stress as main barriers. Second, teachers facing barriers in energy education rather than teachers not facing barriers are inclined to do more education at Ordinance hour and Jongrye hours. It implies that more energy education textbooks for Ordinance hour and Jongrye hours need to be developed. Third, teachers facing barriers in energy education desire more chances for training program, compared with teachers who do not feel barriers. It implies that opportunities for teacher training program need to be expanded.

• Journal of the Korean Solar Energy Society
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• v.28 no.2
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• pp.28-33
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• 2008

The purpose of this study was experimentally to investigate thermal performance of heat pipe for evacuated tubular solar collector. Two sets of evacuated tubular solar collector with different condenser shape of heat pipe were prepared. The experiments were performed under the same operating condition with an indoor testing apparatus. Also, the experiments were carried out various testing conditions including inclination, flow rate, and incident heat flux. The results of thermal performance of collector with enlarged condenser showed that $F_R({\tau}{\alpha})$ was 0.6572 and $F_RU_L$ was -2.0086 at $40^{\circ}$. And the results of thermal performance of collector with straight condenser showed that $F_R({\tau}{\alpha})$ was 0.6233 and $F_RU_L$ was -1.4996 at the same inclined angle.

• International journal of steel structures
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• v.18 no.5
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• pp.1784-1800
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• 2018

Tension-shear loading is a common loading condition in steel structures during the earthquake shaking. To study ductile fracture in structural steel under multiple stress states, experimental investigations on the different fracture mechanisms in Chinese Q235 steel were conducted. Different tension-shear loading conditions achieved by using six groups of inclined notch butterfly configurations covering pure shear, tension-shear and pure tension cases. Numerical simulations were carried out for all the specimens to determine the stress and strain fields within the critical sections. Two tension-shear fracture models were calibrated based on the hybrid experimental-numerical procedure. The equivalent fracture strain obtained from the round bar under tensile loading was used for evaluating these two models. The results indicated that the tension-shear criterion as a function of the shear fracture parameter had better performance in predicting the fracture initiation of structural steel under different loading conditions.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.66-72
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• 1997

This paper aims at reviewing the possibility application over normal or abnormal, detection used by AE and the wear characteristics of grinding process. In this study, when diamond bur in dentistry with chosen grinding conditions were tuned at grinding. The variation of grinding resistance and AE signal is detected by the use of AE measuring system. The tests are carried out in accordance with diamond burs and workpiece: arcyl and bovine. According to the experiment results, the following can be expected: AE has the possibility to detect the state normality and abnormality. Hpwever, the grinding resistance measuring can find it difficult to detect it. It can be accurately excepted from AE occurrence pattern in contact start point of diamond bur and bovine, grinding condition and derailment point. It is known that AErms is well compatible with grinding resistance. According to the increase of the material removal rate, the specific energy of the diamond bur is inclined to dectease and the grinding resistance has a tendency to increase.