• 대한족부족관절학회지
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• 제10권1호
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• pp.71-75
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• 2006

Purpose: To evaluate the results of treatments by percutaneous Acutrak screw fixation for intra-articular tongue type fracture of calcaneus, especially in elderly patient or patients with underlying disease including diabetes mellitus. Materials and Methods: Seven cases with intra-articular tongue type fracture of calcaneus, from November 2003 to February 2005, were reviewed. There were 6 males and 1 female with 65 years old mean age (range: $61{\sim}71$ years old). The average follow-up period was 16 months (range: $10{\sim}25$ months). Two Steinmann pins were used for closed reduction. After closed reduction was done like Essex-Lopresti's method, two Acutrak screws were inserted. The third Acutrak screw was inserted at the sustentaculum tali away from sinus tarsi to fix the primary fracture line. The patients were evaluated with Salama scale, the extent of recovery of Bohler angle, state of subtalar joint. Results: Clinical results according Salama scale were excellent in 5 cases, and good in 2 cases. Average preoperative Bohler angle was $13^{\circ}$ (range: $12{\sim}15^{\circ}$). Average postoperative Bohler angle was 31o (range: $23^{\circ}-40^{\circ}$). There were no soft tissue complications. There were two mild subtalar arthritis. Conclusions: We think that percutaneous Acutrak screw fixation is a good option for tongue type fracture of calcaneus in elderly patient or patients with underlying disease including diabetes mellitus.

• The Journal of Korean Physical Therapy
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• 제13권2호
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• pp.381-397
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• 2001

In the patients with hemiplegia caused by stroke and TBI. postural sway is increased and open displaced laterally over the non-affected leg, reflecting asymmetry in weight bearing on lower extremities during standing balance. Recovery of symmetric weight bearing and postural stability is an important aim in physical therapy. Plastic AFO has been used for hemiplegic patients in order to help their abnormal walking patterns. Past studies have mainly focused on the AFO influences on hemiplegic walking patterns without balance function approaches. The purpose of this study was to identify the immediate effects of plastic AFO and shoes on the static balance in hemiplegic patients. The scale for static balance were weight bearing on affected leg(%), sway area(mm2), sway path(mm), maximal sway velocity(mm/s), anteroposterior sway angle($^{\circ}$ ), and lateral angle($^{\circ}$ ). Seventeen hemiplegic patients participated in this study: 13 men and 4 women, with an average age of 50.18 years. Static balance was measured using BPM(balance performance monitor; dataprint software version 5.3) under four standing condition namely bare-foot standing. standing in shoes, standing with AFO, and standing in shoes with AFO. In order to assure the statistical significance of the results, an one-way ANOVA, the independent t-test. and a pearson's correlation were applied at the .05 level of significant. The results of this study were as follows: 1) There were statistically significant differences in weight bearing(%) on the static balance between affected leg and non-affected leg(p<.01). 2) There were statistically significant differences in sway reverse frequence(Hz) in standing with AFO between affected leg and non-affected leg(p<.05). 3) Sway area(mm2) on standing in shoes with AFO was lower than bare-foot standing(p<.05), Lateral sway angle($^{\circ}$ ) on standing in shoes with AFO was lower than bare-foot standing and standing in shoes(p<.05). 4) Weight bearing in affected leg was not significantly correlated with postural sway.

• 대한족부족관절학회지
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• 제12권2호
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• pp.168-173
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• 2008

Purpose: To evaluate the results of treatments by percutaneous Acutrak screw fixation for intra-articular joint depression type fracture of calcaneus. Materials and Methods: Thirteen cases with intra-articular joint depression type fracture of calcaneus, from September 2004 to March 2006, were reviewed. There were 9 males and 4 females with 52.5 years old mean age (range: $31{\sim}74$ years old). The average follow-up period was 18 months (range: $8{\sim}32$ months). Steinmann pins and Freers were used for closed reduction. After closed reduction, Acutrak screws and K-wires were inserted. The patients were evaluated with Creighton-Nebraska health foundation assessment sheet for calcaneal fracture, the extent of recovery of Bohler angle, fragment size, and state of subtalar joint. Results: Clinical results according to Creighton-Nebraska health foundation assessment sheet for calcaneal fracture were excellent in 6 cases (46%), good in 4 cases (30%), fair in 2 cases (15%), and poor in 1 case (7%). Average preoperative Bohler angle was $7.6^{\circ}$ (range: $2^{\circ}{\sim}13^{\circ}$). Average postoperative Bohler angle was $24.4^{\circ}$ (range: $4^{\circ}{\sim}33^{\circ}$). There were no soft tissue complications. There were one mild subtalar arthritis and one moderate subtalar arthritis. Conclusion: We think that closed reduction and percutaneous Acutrak screw fixation with or without K-wire is a good option for joint depression type fracture of calcaneus.

• Journal of Biosystems Engineering
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• 제25권6호
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• pp.489-496
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• 2000

This study was conducted in order to find an ideal working fluid kind and a proper filling amount in the heat pipe as well as an inclined angle of heat pipe when they are placed to recover exhaust gas heat in the hot air heater. Followings are the findings of this research. 1. Of the four different working fluids-gasoline kerosene distilled water and acetone-acetone filled heat pipe showed the best performance giving out more homogeneous temperature profile on the radiating part than the kerosene and gasoline heat pipe an carrying out heat transmitting function better than the distilled water heat pipe by 10~2$0^{\circ}C$ higher on the radiating part. Acetone would be a good choice for recycling of exhaust gas heat in the hot air heater. 2. Of the filling amount of working fluid inside the heat pipes dry-out situations possible caused by insufficient filling were found in the filling amount of 5, 7.5 and 10% heat pipes as heat supply rate increases gradually in the range of 50 to 15kJ/sec. but no dry-out and stabilized heat transmitting performance occurred in the heat pipes of 12.5 and 15% filling at the same heat supply rate. It recommends that filling amount shall exceed 12.5% at least with the working fluids of this experiment. 3. The test revealed that the heat transmitting performance of heat pipe was more affected by filling amount rather than inclined angle.

• 대한조선학회논문집
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• 제44권6호
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• pp.551-563
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• 2007

Numerical analysis for flow characteristics of a twin skeg container ship was carried out according to skeg vertical angles($0^{\circ}$, $10^{\circ}$, $20^{\circ}$) and skeg distances(16m, 20m, 24m) by using a commercial CFD code, FLUENT. Computed: pressure distributions, wake distributions and resistance coefficients have been compared with experimental and WAVIS results carried out by MOERI. Flow characteristics from numerical analysis such as nominal wake fractions, wake distribution and directions of the transverse vectors give good agreement with WAVIS results, even though there are quantitative discrepancy comparing with experimental measurements at the propeller plane. It is found that the better resistance performance can be obtained with the increase of the skeg vertical angle and the decrease of the skeg distance, which are mainly caused by viscous pressure resistance due to the skeg form and pressure recovery around the skeg. In addition, a vertical angle of the skeg gives more effect to the resistance coefficient comparing with the skeg distance. On the basis of results of the present study, it shows that numerical analysis using the commercial code, FLUENT, is useful and efficient tool for the evaluation of the complex stern hull form with twin-skegs.

• International Journal of Fluid Machinery and Systems
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• 제3권1호
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• pp.11-19
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• 2010

The performance of the crossover system of a centrifugal compressor stage consisting of static components of $180^{\circ}$ U-bend, return channel vanes and exit ducting with a $90^{\circ}$ bend is investigated. This study is confined to the assessment of performance of the crossover system by varying the shape of the return channel vanes. For this purpose two different types of Return Channel Vanes (RCV1 and RCV2) were experimentally investigated. The performance of the crossover system is discussed in terms of total pressure loss coefficient, static pressure recovery coefficient and vane surface pressure distribution. The experimentation was carried out on a test setup in which static swirl vanes were used to simulate the flow at the exit of an actual centrifugal compressor impeller with a design flow coefficient of 0.053. The swirl vanes are connected to a mechanism with which the flow angle at the inlet of U-bend could be altered. The measurements were taken at five different operating conditions varying from 70% to 120% of design flow rate. On an overall assessment RCV1 is found to give better performance in comparison to RCV2 for different U-bend inlet flow angles. The performance of RCV2 was verified using numerical studies with the help of a CFD Code. Three dimensional sector models were used for simulating the flow through the crossover system. The turbulence was predicted with standard k-$\varepsilon$, 2-equation model. The iso-Mach contour plots on different planes and development of secondary flows were visualized through this study.

• 한국항공우주학회지
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• 제47권3호
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• pp.195-203
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• 2019

극초음속 영역에서 운용되는 스크램제트엔진의 흡입구는 엔진 전체 성능에 직접적으로 연관되어 있으므로 개발에 앞서, 다양한 조건에서의 성능 특성 분석이 필수적이다. 본 연구에서는 축대칭 내부 압축형 흡입구인 Busemann과 외부 압축형 흡입구 형상을 설계하고, 설계점 및 탈설계점에서의 전산해석을 수행하였다. 해석결과를 토대로, 마하수와 받음각에 대한 극초음속 흡입구의 전반적인 성능 특성을 파악하였다. Busemann 흡입구는 $2^{\circ}$의 Truncation 각에 따라 흡입구의 길이를 단축하여도 성능 저하가 미미하였으며 탈설계 마하수에서는 흡입구 성능이 우수하였으나, 받음각이 있는 경우 시동 특성이 크게 저하되었다.

• 대한통합의학회지
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• 제11권3호
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• pp.195-204
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• 2023

Purpose : This study applied general training (control group) or cranio-cervical flexor training (experimental group) using a pressure biofeedback unit along with general training for 4 weeks to secondary school teachers with moderate to severe neck pain and forward head posture. After that, we tried to compare the effects through differences in neck pain intensity (using numberical rating scale), functional performance (using neck disability index), and cranio-vertebral angle change. Methods : All 50 subjects were randomly assigned to either the "experimental group (n= 25)" or the "control group (n= 25)", and the measurements were evaluated in the same way before the intervention (baseline) and after the intervention (4 weeks). During the intervention period, the subject visited the physiotherapy center and made a reservation three times a week at a fixed time as much as possible, and each training session was thoroughly conducted under the 1:1 guidance of the therapist in charge so that the correct movement and number of times could be performed without compensatory action. Results : As a result of the homogeneity analysis on the general characteristics of the subjects, there were no significant differences between the groups in all variables (p>.05). Compared to the "control group", the "experimental group" showed significant improvement after intervention in all measured variables of neck pain intensity, functional performance, and cranial-vertebral angle (p<.05). Conclusion : For secondary school teachers with forward head accompanied by neck pain, cranio-cervical flexor training using a compression biofeedback unit is an excellent method to show superior pain reduction and functional performance improvement compared to general training alone. In addition, it can be presented as a more effective intervention method that can promote recovery of forward head posture, which is an essential element of the solution.

• Journal of Biosystems Engineering
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• 제7권2호
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• pp.72-85
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• 1983

Rice whitening is performed by basically two different whitening actions known as abrasive and frictional. The former adopted in the emery stone abrasive type whiteners and the latter in the jet-air friction type. Comparative milling yields and whitening efficiencies between the whitening system consisting of jet-air friction type whiteners only and the system consisting of both abrasive- and jet-air friction-types have not yet been rigorously defined. This study was to examine the effect of combined operations of abrasive- and jet-air friction-type rice whiteners on milling yields and whitening efficiencies. The small capacity commercial units of the abrasive- and friction-type whiteners were used for the experiments. The combinations of whitening treatments were: 1) Once in the abrasive type and then two to three times in the friction type, 2) twice in the abrasive and then two to three times in the friction type and 3) three to five times in friction type. In these tests, counter pressures for the friction type whiteners were established differently as required to get about the same degree of whitening at the end of predetermined numbers of the repeated operations. The speed of emery stone and the slot angle of the screen were also the factors varied in the abrasive type whitener. Sheukwang rice variety having 13.05% M.C. was used in the tests. The dependent variables were the milled- and head-rice recoveries and electricity consumption. The results of the study are summarized as follows: 1. It was found that in the whitening systems consisting of abrasive- and friction-type whiteners slot angle of the screen, the rotational speed of emery stone roller had significant effect on the milling yields and whitening efficiency. In general, the increase of the emery stone roller speed from 690 to 950 rpm presented a positive effect on milling yield, and one-pass abrasive milling combinations had higher milling yields than two-pass abrasive milling combinations. 2. It was apparent that if the slot angle of the screen and the speed of emery stone roller are modified and set at an optimum level, the combination whitening system consisting of abrasive- and friction-type whiteners is better than the pure frictional whitening system consisting of jet-air friction type in terms of milling yields and efficiencies. 3. In the rice whitening system consisting of abrasive- and jet-air friction-type whiteners, the best whitening performance was obtained when the slot angle of the screen and the rotational speed of emery stone roller were $45^{\circ}$ and 950rpm, respectively, for the one-pass abrasive milling combinations. However, for the two-pass abrasive mi11ing combinations, the best performance was obtained with $75^{\circ}$ of slot angle and 950 rpm of the emery stone roller speed. 4. As compared with pure frictional whitening systems, the combination systems produced more milled rice by 0.8-1.0% point and more head rice by 0.5-1.5% point, and consumed less electricity by 0.15-0.20 KwH per 100kg of milled rice when the abrasive whiteners were operated in the modified conditions as described in item 3 above. Further study is recommended to find out optimum operational and design conditions of abrasive type whiterners.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.245-248
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• 2008

This paper deals with the parameter study of roller leveling process of steel cord using finite element analysis. A simplified model of roller leveling process is constructed for the efficient numerical simulation considering the computing time. Using the constructed simulation scheme, the parameter study of main process parameters, such as back-tension and intermesh, is carried out in order to evaluate elastic recovery angle and roller force quantitatively. The effect of the initial shape of steel cord is also evaluated during the parameter study. And the mechanism of roller leveling process is verified by investigating the residual stress distribution.