• Geomechanics and Engineering
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• 제22권1호
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• pp.35-48
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• 2020

This paper provides methods for the deterministic and reliability-based design of the support pressures necessary to prevent tunnel face collapse. The deterministic method is developed by extending the use of the unique load multiplier, which is embedded within OptumG2/G3 with the intention of determining the maximum load that can be supported by a system. Both two-dimensional and three-dimensional examples are presented to illustrate the applications. The obtained solutions are validated according to those derived from the existing methods. The reliability-based method is developed by incorporating the Response Surface Method and the advanced first-order second-moment reliability method into the bisection algorithm, which continuously updates the support pressure within previously determined brackets until the difference between the computed reliability index and the user-defined value is less than a specified tolerance. Two-dimensional reliability-based support pressure is compared and validated via Monte Carlo simulations, whereas the three-dimensional solution is compared with the relationship between the support pressure and the resulting reliability index provided in the existing literature. Finally, a parametric study is carried out to investigate the influences of factors on the required support pressure.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.1156-1159
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• 2017

한국형발사체 및 시험발사체에 대한 지상 운용을 위해서는 우주센터 종합조립동 내에 여러 가지 지상지원장비가 필요하다. 여러 가지 지상지원장비 중 발사체 접속장치와 고압유연배관은 지상의 고압가스 공급장비와 발사체 사이에 고압배관 연결을 위해 필수적인 장비이다. 본 논문에서는 고압가스 연결을 위해 필요한 발사체 접속장치와 고압유연배관에 대한 개요와 개발 진행 상황에 대해 소개하고자 한다.

• 대한물리치료과학회지
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• 제11권4호
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• pp.29-37
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• 2004

Measurements of plantar pressure provide an indication of foot and ankle function during gait and other functional activities because the foot and ankle provide necessary support and flexibility for weight bearing and weight shifting while people are performing these activities. Plantar pressure is being increasingly used in both research and clinical practice to measure the effects of various footwear and physical therapy intervention. The influence of walking speed and ground inclination on plantar pressure parameters However has not been evaluated in detail. So, in this study to determine the effect of changes in walking speed and ground inclination on plantar pressure treadmills with different walking speeds and inclination were used. Plantar pressure parameters were measured with the Parotec system using the walking and running in 20 healthy participants(10 male, 10 female) aged $20{\sim}28$(mean 22.22, S.D.2.26 years) when slow walking and running. The result of this study with increased die walking speed, the peak pressure of 1st, 5th metatarsal head and total contact time and impulse total at the forefoot was affected by walking speed; however, die peak pressure, contact time and impulse total at the forefoot was not affected by ground inclination.

• 한국기계가공학회지
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• 제10권3호
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• pp.1-6
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• 2011

This study focused on the localization of swivel type tube couplers, which all depend on imports. In this study, a computer application analysis was performed using a finite element method as a preliminary study. In the major developments related to the objective of this study, the air brake system produced by car makers represents a different in the installation point of an air tank according to the type of cars or in the length and direction of its hoses and that leads to cause lots of problems. For solving such problems, the design of the major elements in a swivel type tube coupler was analyzed using a finite element method, and its validity was also verified. In the process that verifies the validity of this study, it was necessary to investigate how much external force affects the desorption of the tube support, which is the most important element in swivel type tube couplers. For achieving the investigation, a pressure test was implemented for the tube support according to the Federal Motor Vehicle Safety Standards(FMVSS). In the results of the pressure test, all samples satisfied the FMVSS. In addition, several tests were implemented by installing the sample of the developed swivel type tube coupler to an actual vehicle. In particular, rotation tests with various angles were applied by welding the swivel type coupler to an air tank through an argon welding process. In the results of the installing test for an actual vehicle, it was verified that the designed structure was determined as a structure that is able to endure the eccentric torque and deformation pressure applied to several directions that are the major problems in such fixed type tube couplers. Therefore, in the comparison of the performance of the developed product with the product of PARKER, it was possible to verify that the localized swivel type tube coupler developed in this study shows more excellent than that of the existing products by PARKER.

• 대한기계학회논문집A
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• 제31권8호
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• pp.896-902
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• 2007

The tunnel stability concerned with safety is very important in coal production process. The tunnel supports made by the GI beam has been used in domestic coal mine tunnels, and the GI beam was connected with another by the fish plate. It is necessary to analysis for the bending problems of the fish plate due to the rock pressure in some domestic mine tunnels. Therefore, this study proposes the application possibility of the optimization algorithms for the problem searching a load condition that bring about bending problem in tunnels. Consequently, in order to investigate the load conditions, desirability function as one of the optimization methods to study the bending behavior of tunnel supports was applied.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2046-2052
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• 2008

For the lighting of vehicles structural casting components of aluminum casting alloys are substituted for those of steel or iron. For the manufacturing of large-scale premium quality aluminum castings the developments of a new casting process and a heat treatment process are necessary. The optimum casting design and heat treatment condition for large-scale castings are drawn with the help of Z-Cast software for the casting process analysis in this study. Low pressure sand casting method is applied successfully to produce air bag support components of D357 aluminum casting alloy.

• 한국압력기기공학회 논문집
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• 제9권1호
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• pp.20-24
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• 2013

Reactor Vessel Internals(RVIs), which are installed within the reactor pressure vessel and support the fuel assembly, take responsibility for safety of reactor core. In operating Nuclear Power Plants(NPPs), the RVIs have been exposed to severe conditions such as neutron irradiation, high temperature, high pressure, and high velocity of coolant flow and have degraded by materials aging with long-term operation. Therefore, the effective aging management plan and the appropriate regulatory requirements are necessary to maintain the integrity of RVIs. The purpose of this paper is to provide a review guide for Periodic Safety Review(PSR) of RVIs in presurized water reactor. The review guide is developed based on the revised review guides and reports established from IAEA and USNRC, and the analysis results of design characteristics, aging mechanisms, and operating experiences of RVIs in domestic and international NPPs. Consequently, the developed review guide for PSR of RVIs is expected to contribute an overall strategy and standard for the PSR of RVIs.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.545-550
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• 2004

KSTAR cryostat is a 8.8 m diameter vacuum vessel that provides the necessary thermal barrier between the ambient temperature test cell and the supercritical helium cooled superconducting magnet providing the base pressure of 1 ${\times}$ $10^{-3}Pa$. The cryostat is a single walled vessel consisting of central cylindrical section and two end closures, a flat base structure with external reinforcements and a dome-shaped lid structure. The base structure has 8 equally spaced support legs anchored on the concrete base. The cryostat vessel design was executed to satisfy the performance and operation requirements. The major loads considered in the structural analysis were vacuum pressure, dead weight, electromagnetic load driven by plasma disruption, and seismic load. Based on the fabrication and inspection procedures for the vessel, cryostat vessel was fabricated and inspected. It was confirmed that the inspection results were acceptable.

• 상하수도학회지
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• 제34권5호
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• pp.335-344
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• 2020

Due to global climate change, mega-droughts have occurred frequently. Since long-term droughts make it difficult to secure the water resources, water supply needs to be restricted in a reasonable manner. In the event of limited water supply, the waterworks need to develop a restricted water supply strategy. This study showed that analyzing daily water supply could be used to respond to the first stage of a drought. According to an analysis of Korea's major water authorities, there was about 7~21% of room for daily minimum water supply in case of a drought. Restricting the water supply by lowering pressure is a good strategy for local water authorities with high water leakage rate since leakage is inversely dependent with pressure. For this method, it is necessary to quantify water deficiency and pressure at each node using a simulation. Since DDA-based software is not possible to predict changes in demand at nodes with pressure reduction, WaterGEMS, a PDA software, was used to quantitatively predict water shortages and pressures at each node. Locations where water is deficient need to install booster pumps or to be dispatched with water tank truck and bottled water. Without these support, lowering pressure could not be an option for water works. This paper suggests a method for waterworks to plan a drought by lowering pressure to restrict water supply using daily water supply analysis and PDA based simulation.

• 한국농촌간호학회지
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• 제15권2호
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• pp.49-56
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• 2020

Purpose: This descriptive correlational study was done to analyze the relationship between social support and self-care in hypertensive patients aged 30 years or older. Methods: Data were collected from April 09 to April 16, 2020 through an online survey (Naver Form) at Internet cafes and SNS Eighty 80 adults aged 30 or older who had been diagnosed with high blood pressure at a medical institution participated in the study. Data were analyzed using t-test, one-way ANOVA, Scheffé's test and Pearson correlation coefficients with SPSS statistics 26.0. Results: The study results showed that social support for hypertensive patients was significantly higher for men (t=-2.17, p=.033), according to religious status (t=-2.33, p=.023), and the number of people in the household (F=6.05, p=.001). In addition, there was a significant positive correlation between social support and hypertensive self-care (r=.24, p=.036). Conclusion: The results confirm that the social support of patients with hypertension is related to self care for hypertension management. As the number of elders and single-person households who cannot manage their health well increases, it is necessary to establish a long-term and continuous social support system for these clients.