• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.8
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• pp.1122-1130
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• 2001

Film cooling performance from two rows of holes with opposite orientation angles is evaluated in terms of heat flux ratio. The film cooling hole has a fixed inclination angle of 35°and orientation angle of 45°for the downstream row and -45°for the upstream row. Four film cooling hole arrangements including inline and staggered configurations are investigated. The blowing ratio studied was 1.0. Boundary layer temperature distributions are measured to investigate injectant behaviors and mixing characteristics. Detailed distributions of the adiabatic film cooling effectiveness and the heat transfer coefficient are measured using TLC(Thermochromic Liquid Crystal). For the inline configuration, there forms a downwash flow at the downstream hole exit to make the injectant well attach to the wall, which gives high adiabatic film cooling effectiveness and heat transfer coefficient. The evaluation of heat flux ratio shows that the inline configuration gives better film cooling performance with the help of the downwash flow at the downstream hole exits.

• Journal of Korean Foot and Ankle Society
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• v.7 no.1
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• pp.30-35
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• 2003

Purpose: The purpose of this study was to evaluate the result of open wedge osteotomy at the anterior calcaneus with iliac bone graft (Evans procedure) for symptomatic flexible flatfeet in children. Materials and Methods: A retrospective study was conducted between October 1995 and September 2002. Six cases in 3 patients who had symptomatic flexible flatfeet was included. Follow-up averaged 39.5 months. We evaluated the patients' satisfaction by Mann and Reynolds scorring and compared the radiographic results between preoperative and final radiography. Results: The satisfaction outcomes at the last follow-up were excellent in five and good in one. The mean lateral talo-first metatarsal angle was improved from $-20^{\circ}$ to $-3^{\circ}$. The mean calcaneal inclination angle was improved from $8.5^{\circ}$ to $20.8^{\circ}$. The talo-navicular coverage angle was improved from $47.5^{\circ}$ to $7.5^{\circ}$. In one case, we found the subluxation of calcaneocuboidal jont in postoperative radiography. Conclusion: Open wedge osteotomy at the anterior calcaneus for symptomatic flexible flatfeet in children was considered as one of the effective treatment methods.

• Solar Energy
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• v.17 no.4
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• pp.45-56
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• 1997

The purpose of this research was to study the characteristics of heat transfer of snow removing facilities using heat pipe by experimental method. Heat pipes was constructed a flexible tube connected between evaporator and condenser ends for altitude adjustment of evaporator and it was constituted an internal diameter of 25.4mm, a length of 950mm for heating section and a length of 6000mm for condenser section with copper material for closed system. The results showed that the effect of heat transfer was increased when inclination angle and inlet temperature of heating water increased. Wall temperature response by inclined angle $4.5^{\circ}c-9^{\circ}c$ and working fluid amount 0.96 from to 1.3 times of evaporator volume were better than those of other working fluid and angle.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.3
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• pp.21-27
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• 2019

PURPOSE: This study examined the changes in the kinematic variables during walking on a downhill ramp according to the shoe heel height. METHODS: The subjects were 10 adult women with no history of musculoskeletal disorders who agreed to participate in the study. Data were collected using a motion analysis system (VICON) consisting of six infrared cameras. The slope was 120 cm in width, 200 cm in length, and 15 in inclination. To confirm the change in gait parameters (stride length, gait speed) and lower extremity joint angle according to the heel heights of the shoes, flat, 5 cm, and 10 cm heel shoes were prepared and walked alternately. RESULTS: As a result, both the stride length and walking speed showed significant differences according to the heel height between flat and 10 cm (p<.05). In the sagittal plane, there was no significant difference in the hip joint and knee joint, but a significant difference was observed in all events in the ankle joint on all heel heights (p<.05). In particular, the heel strike and mid stance events showed significant differences among all height conditions (p<.05). No significant difference was observed in any of the joint angle changes in the frontal plane (p>.05). CONCLUSION: As the shoe heel height increased, the instability increased and efforts to secure the stability were made, leading to a shortened stride length, walking speed, and angle of the ankle joint.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.12
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• pp.1079-1089
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• 2013

The flow characteristics in a solid particle incinerator are investigated numerically for high burning rate of wastes. The studied incinerator employs both a swirl flow used in the furnace of powerplants and a design concept applied to a rocket combustor. As the first step, the non-reactive flow field is analyzed in the incinerator with primary and secondary injectors through which solid fuel and air are injected. The deflection angle of a primary injector, inclination angle of a secondary injector, and gap between the two types of injectors are selected as design parameters. The swirl number is adopted for evaluating the degree of swirl flow and estimated over wide ranges of three parameters. The swirl number increases with deflection angle, but it is affected little by inclination angle. Recirculation zones are formed near the injectors, and their size affects the swirl number. The swirl number decreases with the zonal size of recirculation. From the numerical results, the design points can be found with strong swirl flow.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.221-235
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• 2005

The purpose of this study was to analyse badminton players' drop-shots, in order' to make players understand the principles of drop-shot motion in badminton. Three dimensional analysis was used to measure movements such as the time required per section, the change of center of gravity, joint angle and speed, and joint speed. The results of this study revealed as follows: (1) top players are faster than amateurs in the total time required per section; (2) top players moved more in the x-axis and z-axis, while amateurs moved more in the y-axis; (3) the inclination of amateurs was greater than that of top players in all phases; (4) amateurs showed larger angle on the shoulder joints than top players in the first phase, while top players showed larger angle on the shoulder joint than amateurs in the second and third phase. Amateurs' angle was larger on angle joint in the first phase than top players' ones, while top players' angle was larger in the third phase than amateurs; (5) the speed of racket head of top players was faster than that of amateurs; and the velocity of the center of gravity of amateurs was greater than that of the top players. The findings of this study were that gravity decreases during impact and then the velocity increases to perform the follow-through and making the swing fast by increasing the speed of the racket head is most important.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.761-770
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• 2009

The purpose of this study was to observe the kinematic patterns of hurdling by domestic hurdlers and elite hurdlers from other countries in particular, we studied the hurdling motion and joint angles at the third hurdle in 110-m hurdle races. There were slight differences in the following variables at takeoff and landing: angle of the center of gravity(elite hurdler, $34.14^{\circ}$ domestic hurdler, $24.89^{\circ}$), angle variables the body angle(elite hurdler, $4.27^{\circ}$ domestic hurdler, $6.37^{\circ}$), the angle of trunk inclination(elite hurdler, $3.18^{\circ}$ domestic hurdler, $11.58^{\circ}$), and the hip angle(elite hurdler, $40.1^{\circ}$ domestic hurdler, $43.2^{\circ}$).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.3
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• pp.108-114
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• 2018

One of the most performed action in daily life is standing up from sitting position. As the population of the world is aging at the high rates, people may face problems with reduced muscle strength as well as psychological changes. This can lead elderly people having difficulties with standing up from chair. Now, with the aging trend worldwide, products are being developed that can support the lives of the elderly. This study examines the distribution of hip pressure in relation to the seating positions of the standing assistance seats under development to prevent standing up accidents in older adults. The currently developing standing assistant chair designed to tilt to a maximum angle of 25 degrees. At over $25^{\circ}$, design considers that older people are at risk of thrown back out of that force and that the forces exerted on their arms and legs can be a significant burden to older people. By considering danger of higher than $25^{\circ}$ for older people which is experimented in the basis of static capturing approach in previous papers, it is experimented people with age group of 20~60 on $0^{\circ}$ to $25^{\circ}$ tilting angle on the basis of dynamic capturing method in order to pick convenient angle of inclination. Moreover, tried to find the optimum angle by comparing the hip pressure distribution when seated at the edge of the seat and at the center of the seat with the pressure distribution sensor.

• 재활복지
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• v.22 no.2
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• pp.213-230
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• 2018

The study looked at the impact on the health of the spine caused by the increasing addiction to smart phones, and examine the moderating effect of adjusting spinal health according to cognitive strength. All subjects used the smartphone by measuring the diagnostic scale of the smartphone addiction, the angle of forward inclination of the cervical spine, and the amplitude variation of the cognitive Gamma-Peak of the brain waves. As a result, as the use of smart phones increases, the spine angle significantly increased (p<0.001), as cognitive strength increased, the spine angle decreased significantly (p<0.01). The cognitive strength also showed the effect of adjusting the spine angle through interaction with the degree of use of a smartphone (p<0.05). This results in a higher degree of smartphone use in lower and middle cognition strength groups, which results in a higher angle of forward tilt in the cervical spine.

• The korean journal of orthodontics
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• v.28 no.2 s.67
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• pp.255-268
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• 1998

This study was investigated to assess the difference of facial height and occlusal plane inclination between normal occlusion group and class II malocclusion group. The subjects consisted of 50 normal occlusion (male 25, female 25) and 50 class II(male 25, female 25) malocclusion patients. All subjects are adult. lateral cephalogram was taken with standard method traced, and digitized for each subjects. The computerized statiscal analysis was carried out with SPSS program. The results were as follows 1. In class II malocclusion group, variables significant different from normal occlusion group were as follows ; SN-FOP, FH-BOP, MP-BOP, AB-BOP, AB-FOP, Facial plane-BOP, FP-FOP 2. In class II malocclusion group, the posterior facial height -especially posterior lower facial height-was significantly smaller than normal occlusion group.(P<0.05) 3. In class II malocclusion group, the angles between occlusal plane and upper and lower incisor, the angle between upper molar and bisected occlusal plane were significantly larger than those of normal occlusion group. (P<0.05) 4. L1 to Mandibular plane (mm) was a unique factor of occlusal plane position that showed significant difference in class II malocclusion group. 5. The correlation between overbite and occlusal plane inclination existed in class II malocclusion group, but the correlation didn't exist in normal occlusion group.