• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4477-4490
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• 2023

Fuel locking mechanisms (FLMs) are essential in upward-flow research reactors to prevent accidental fuel separation from the core during reactor operation. This study presents a novel design concept for a remotely controlled plate-type nuclear fuel locking mechanism. By employing electromagnetic field analysis, we optimized the design of the electromagnet for fuel unlocking, allowing the FLM to adapt to various research reactor core designs, minimizing installation space, and reducing maintenance efforts. Computational flow analysis quantified the drag acting on the fuel assembly caused by coolant upflow. Subsequently, we performed finite element analysis and evaluated the structural integrity of the FLM based on the ASME boiler and pressure vessel (B&PV) code, considering design loads such as dead weight and flow drag. Our findings confirm that the new FLM design provides sufficient margins to withstand the specified loads. We fabricated a prototype comprising the driving part, a simplified moving part, and a dummy fuel assembly. Through basic operational tests on the assembled components, we verified that the manufactured products meet the performance requirements. This remote-controlled micro locking mechanism holds promise in enhancing the safety and efficiency of plate-type nuclear fuel operation in upflow research reactors.

• 한국가스학회지
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• 제4권1호
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• pp.63-68
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• 2000

가정용 가스보일러의 안전장치인 새로운 과압방지밸브를 개발하였다. 본 과압방지밸브는 방출용량을 고려하여 입출구의 구경과 시트구경을 확대하였고, 스프링과 난방수가 닿지 않는 밀봉구조로 설계하여 기존 과압방지밸브의 문제점인 입구유로의 고착, 막힘이나 스프링의 부식현상을 최소화하였다. 개발된 과압방지밸브는 시험결과 분출개시압력, 분출정지압력, 밀폐성, 내구성의 성능특성이 우수하였고, 보일러 설치후의 작동성도 우수한 것으로 평가되었다. 본 연구결과를 통한 과압방지밸브의 표준화와 적용은 부품호환뿐만 아니라 유지보수가 용이하다는 장점을 제공할 수 있을 것이다.

• Journal of Korean Biological Nursing Science
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• 제10권1호
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• pp.11-18
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• 2008

Purpose: The purpose of this study was to identify the effect of the physical activity promotion program on physical function and quality of life in the elderly. Method: The research was designed with one single pre-post group. The study group of 295 elderlies were selected through the convenience sampling form in a senior citizen's center in Ulsan city. The subjects received the physical activity promotion program for 60 min three times a week for 3 months. To evaluation the effects of the physical activity promotion program, body mass index (BMI), physiological index, physical function (muscle endurance, agility, balance) and quality of life were measured at before and after the program. The data was analyzed through SPSS 10.0 program for descriptive statistics and paired t-test. Result: After performing the physical action promotion program for 3 months, the results were follows. 1) There were significantly increased in BMI (t=4.36, p=.000). 2) There were significantly decreased in diastolic pressure (t=.68, p=.009). 3) There were significantly improved in muscle endurance (t=6.50, p=.000), agility (t=4.74, p=.000) and Rt. leg balance (t=4.15, p=.000). 4) There were significantly improved in quality of life (t=7.28, p=.000). Conclusion: These findings showed that the physical activity promotion program was effective in improving physical function and quality of life in the elderly. Therefore, the physical activity promotion program could be applied as an effective nursing intervention program for the elderly to promote their health.

• 한국식품영양학회지
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• 제6권4호
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• pp.255-267
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• 1993

This study was performed to investigate the correlations among physical anthropometric measurement, diet intakes, physical fitness test, and serum lipids in eight sedentary women(control group), and twenty seven exercising women(aerobic groups), aged 35~45 years. The results of the study are as follows : 1) systolic blood pressure(SBP) and diastolic blood pressure(DBP) of aerobic groups were lower than serf entary. Pulse rate was decreased according to the length of aerobic periods. Muscular endurance and jump power of all subjects were stronger than standard range, and those of aerobic exercising groups were stronger than control group. Muscular power of the upper half of the body In all subjects were lower than standard range. 2) Daily calorie intakes of all subjects were in the ring: of recommended dietary allowances (RDA) for Koreans. But daily protein Intakes were higher than RDA. daily cholestrol intakes of all subjects were slightly less than 200~300 mg: which is normal consumption of Koreans. 3) There was a significant positive correlation between serum 7G and daily protein intakes. It was considered that excessive protein intake converted to serum 7G. There was not a significant correlation between serum TC and dietary TC. Therefore, dietary TC seemed to have not much effect on serum TC. Physical fitness was negatively related to serum TG, TC, LDL-C, but positively related to HDL-C, HDL-C /TC. It was found that the serum lipids could be changed better according to improving the physical fitness. There were significant positive correlations between SBP and serum TC, LDL-C. (According to this results), the higher SBP, the higher serum TC, LDL-C tended to be. There was a significant positive correlations between sit up and weightloss nth exercise r=0.7(p<0.001), push ups and weightless with exercise r=0.5(p<0.001). It was considered that muscle strength could be improved according to the weightloss. 4) The purpose of exercise in aerobic groups was rather promoting health than reducing body fatness. Most of al1 subjects (83.2%) drank caffeine-contained beverage therefore, we should concern about that absorption of Fe could be Interrupted and blood pressure could be elevated by caffeine.

• 성인간호학회지
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• 제12권2호
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• pp.267-277
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• 2000

The purpose of this study was to help the women with stress urinary incontinence lead more comfortable life, by letting them to do pelvic muscle exercise and to learn by direct experience the effect that urinary incontinence is controlled. The research design was a one-group pretest-posttest design. The subjects were 16 middle-aged women(over 38) with stress urinary incontinence. The study was conducted from August 1, to October 11, 1999. Women trained themselves for muscular strength and endurance, every the other day for each exercise for six weeks at home(that means each exercise for more than three days a week) in the pelvic muscle exercise program which was developed by Dougherty et al., and filled out exercise participation card every week. They visited laboratory once a week to get visual feedback, by means of Perineometer, of how the pelvic muscle exercise was going on. Stress Urinary Incontinence Scale that Lee, Young-Sook revised and supplemented Hendrickson's original scale was used for measuring the frequency and situation scores of urinary incontinence, "30 minute pad test" was carried out for measuring the amount of urinary incontinence, and Perineometer was used for measuring maximum vaginal contraction pressure. Percentage, mean, standard deviation and Wilcoxon signed ranks test were used for data analysis by means of SPSS/PC+ WIN 9.0 program. The results were summarized as follows : The hypothesis 1 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the weekly degree of urinary incontinence would reduce compared to before the exercise was supported. The hypothesis 1-1 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the weekly frequency of urinary incontinence would reduce compared to before the exercise was supported (p=.003). The hypothesis 1-2 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the situation scores of urinary incontinence would reduce compared to before the exercise was supported(p=.044). The hypothesis 2 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the amount of urinary incontinence would reduce compared to before the exercise was supported(p=.001). The hypothesis 3 that after carrying out pelvic muscle exercise program on women with stress urinary incontinence, the maximum vaginal contraction pressure would increase compared to before the exercise was supported (p=.012). These results suggest that pelvic muscle exercise program has an effect on women with stress urinary incontinence in the degree and amount of urinary incontinence and maximum vaginal contraction pressure. So it is judged that training women with stress urinary incontinence for pelvic muscle exercise is an effective nursing intervention strategy in order to care urinary incontinence.

• 한국전산구조공학회논문집
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• 제32권5호
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• pp.279-286
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• 2019

본 논문에서는 가스건 시험에서 원충격자의 충격 감가속도 예측에 관한 전산해석적 연구를 수행하였다. 무기체계 개발에 있어서, 가스건 시험을 통한 수만 G 이상에서의 내고충격성능에 대한 검증은 필요하다. 시험품이 받는 충격 감가속도는 버드조립체의 형상, 무게, 비행 속도 등 여러 변수에 의존하기 때문에 충격 감가속도를 생성시키는 적합한 시험조건을 찾는 것은 매우 중요하다. 하지만, 시험을 통해 기본적인 데이터를 구축하는 것은 경제적인 측면에서 비효율적이기 때문에 전산해석적 기법을 확보하여야 한다. 이에 본 연구에서는 130mm 가스건 시험을 바탕으로 획득한 데이터를 기반으로 하여 Explicit 코드를 사용하는 ANSYS AUTODYN을 활용하여 전산해석을 수행하였다. 전산해석을 통해, 시간에 따른 시험품의 동적거동현상 뿐만 아니라 전산해석결과를 시험결과와의 비교 및 분석을 함으로써 검증을 수행하였다.

• 한국산학기술학회논문지
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• 제19권11호
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• pp.521-528
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• 2018

전투목적으로 개발된 군용차량은 타이어 압력이 손실되더라도 일정시간동안 일정거리를 달릴 수 있도록 런플랫시스템을 도입하였다. 런플랫을 적용하기 위하여 휠을 외측림과 내측림으로 구성된 2개의 부분으로 구성하고, 클램핑 볼트를 체결함으로써 외측림과 내측림을 조립한다. 이 클램핑 볼트는 휠의 내구성을 결정하는 중요 부품이다. 실제로 휠의 내측림과 외측림의 파손보다는 클램핑볼트의 파손이 발생되어 휠을 사용하지 못하는 빈도가 높다. 따라서, 클램핑 볼트의 내구성능이 휠의 내구성능과 연관이 크다고 할 수 있다. 본 연구는 휠의 내구성을 향상시키기 위하여 휠조립체를 시험하고 클램핑 볼트를 개발하는 과정을 다루었다. 기존에 정립된 내구시험 조건의 불충분성을 식별하였으며, 휠조립체의 내구성을 보다 정확히 확인할 수 있도록 통제해야 하는 시험조건을 제시하였다. 정립된 시험조건을 기반으로, 성능이 개선된 클램핑 볼트를 시험하였다. 시험조건을 확인한 결과 기존 제품보다 최소 168% 내구성이 향상됨을 확인할 수 있었다. 본 연구는 휠 조립체의 내구시험 방법과 클램핑 볼트를 개발하는 과정에서 고려해야 할 요소를 제시한 것에 의미가 있다 할 수 있다.

• 한국유체기계학회 논문집
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• 제7권1호
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• pp.30-35
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• 2004

The HANARO, a multi-purpose research reactor of 30 MWth open-tank-in-pool type, has been under normal operation since its initial criticality in February, 1995. Many experiments should be safely performed to activate the utilization of the HANARO. HANARO flow simulation facility is being developed for the endurance test of reactivity control units for extended life time and the verification of structural integrity of those experimental equipments prior to loading in the HANARO. This facility is composed of three major parts; a half-core structure assembly, a flow circulation system and a support system. The flow circulation system is composed of a circulation pump, a core flow piping, a core bypass flow piping and instruments. The system is to be filled with de-mineralized water and the flow should be met the design requirements to simulate a similar flow characteristics in the core channel of the half-core structure assembly to the HANARO. This paper, therefore, presents an analytical analysis to study the flow behavior of the system. Computational flow analysis has been performed for the verification of system pressure variation through the three-dimensional analysis program with the standard $k-{\epsilon}$ turbulence model and for the verification of the structural piping integrity through the finite element method. According to the analysis results, it could be said that the design requirements and the structural piping integrity of the flow circulation system are satisfied.

• 한국정밀공학회지
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• 제33권9호
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• pp.723-730
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• 2016

This paper presents a cable-driven hydraulic actuator named Cable Rod Hydraulic Actuator (CRHA). The cable actuating system is attractive for designing a compact joint in robotic applications since it can be installed remotely from the joint. Recently, cable rods have been used in pneumatic area for inertia reduction. However, designing cable rods in hydraulics is challenging because it is difficult to achieve flexibility and endurance simultaneously under high pressure conditions. In this paper, the cable rod, which consists of a cable and jacket, is proposed to meet both requirements. To design the CRHA, we determined the design parameters, such as cylinder size, and selected the cable rod's material by friction and leakage test. Finally, comparisons experiments about step and frequency responses with conventional hydraulic actuators were performed to assess feasibility for robotic joints, and the results show that the proposed system has good bandwidth and fast response as robotic joints.

• 한국노년학
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• 제29권1호
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• pp.135-147
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• 2009

최근 우리나라는 식생활의 서구화와 더불어 운동부족 등으로 고혈압 발병률이 급격히 증가하고 있다. 많은 연구자들은 운동요법으로서의 고혈압 처치 및 예방을 위하여 다각도적인 접근을 시도하고 있다. 그러나 대부분의 연구들이 혈압강하와 관련된 운동의 효과 분석, 운동프로그램의 유용성 분석 등에 한정되어 있으며, 연령별 고혈압여부에 따른 체력의 차이에 대한 분석은 이루어지지 않고 있다. 본 연구자는 국민건강 관점에서 볼 때 연령별 고혈압여부에 따른 체력 수준 차이에 대한 확인은 고혈압 예방 및 처치를 위한 핵심적인 자료가 될 수 있기 때문에 금후에 진행되어야 할 중요한 연구 과제라 생각한다. 따라서 본 연구는 20대 이상의 성인 여성을 대상으로 연령별 고혈압여부에 따른 체력의 차이를 확인하여 고혈압 예방에 대한 체력수준의 중요성을 강조하고자 한다. 또한, 심폐기능의 차이를 추가적으로 살펴봄으로써 보다 가치 있는 연구를 도모하고자 한다. 2004년 1월 2일부터 2008년 9월 31일까지 S시 Y구 보건소 내 건강증진센터를 방문하여 고혈압검사가 포함된 종합검진을 받은 20세 이상의 성인 여성 8889명을 분석대상으로 하였다. 미국 고혈압 합동위원회의 제7차보고서(JNC7)의 고혈압 기준에 따라서 정상군, 조기고혈압군, 고혈압1기군과 고혈압2기군으로 나누었다. 심폐기능의 평가는 안정시심박수와 폐활량으로 체력의 평가는 심폐지구력, 근지구력, 근력, 순발력, 민첩성, 평형성, 유연성으로 하였고, 고혈압 발병에 영향을 미치는 독립 위험변수인 체질량지수, 음주, 흡연을 보정한 공변량분석(ANCOVA)을 이용하여 체력차이를 분석하였다. 연구결과 2가지의 모든 심폐기능 변인, 7가지의 모든 체력 변인에서 대부분의 연령대별로 4집단 간의 유의한 차이가 나타나는 것을 확인하였다. 이를 통하여 정상군에서 고혈압군으로 혈압수준이 높아질수록 낮은 심폐기능과 낮은 체력수준을 소유하고 있는 것을 확인하였다.