• Nuclear Engineering and Technology
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• 제41권8호
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• pp.1127-1134
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• 2009

Concrete has three major properties after a penetration-reinforcing agent is applied on its surface. First, the durability is improved by the sol-gel process of synthesized material from the polycondensation of TEOS (tetra-ethoxyorthosilicate) and acrylate monomer. Second, the capability to absorb impact energy is reinforced through the formation of a soft and flexible layer of organic monomers by Tea (Tetra Ethyl Amin). Third, the capability to prevent deterioration is enhanced by adding isobutyl-orthosilicate and alcohol. The performance and application of an agent developed through the synthesis of organic and inorganic material in an effort to prevent concrete from deterioration and improve the durability of concrete structures were verified in diverse experiments. The results of these experiments showed that the application of the proposed penetration-reinforcing agent has the effect of increasing the compressive strength by filling up the internal pores of concrete with physically and chemically stable compounds after penetrating the concrete. It also improves the durability against the deterioration factors such as salt water damage, carbonation, freezing and thawing, and compound deterioration. Therefore, it is confirmed that the penetration-reinforcing agent is a useful substance for the management and repair of concrete structures.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.573-578
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• 2004

Rotem has chosen ADAMS/Rail as the next generation analysis tool, to improve the capability and accuracy of the analysis ability. The dynamic performances of the railway vehicle, which is designed and manufactured by Rotem, have been analyzed and simulated using ADAMS/Rail. In this paper, Dynamic stress of bogie frame on running track is analyzed and compared with the data of real vehicle test. It is performed using ADAMS/AutoFlex and ADAMS/Durability.

• 한국ITS학회 논문지
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• 제9권5호
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• pp.87-95
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• 2010

도시의 많은 교량 구조물은 내구연한 및 노후 상태에 따라 외형적 변형이 발생하고, 지진과 태풍 등은 노후 시설물의 변형을 더욱 악화시키고 있다. 불규칙하고 미세한 점진적 외형 변형은 육안으로 확인하기 어렵고, 시설물의 성능을 저하시키게 된다. 따라서 최근에 교량 구조물의 이상 거동을 실시간의 무선 방식으로 검지하는 기술이 연구되고 있다. 본 연구는 자이로스코프를 이용하여 구조물의 미소한 물리적 변화량을 실시간으로 측정하는 변위측정모듈을 개발하였다. 개발된 계측 모듈의 성능은 시뮬레이션 실험을 통해 검증하였다.

• 한국자동차공학회논문집
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• 제20권2호
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• pp.141-147
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• 2012

Engine mount is used to soften the impact of bumper with elasticity recovery and damping capacity. Inner noise and vibration to influence the comfortableness for passenger cause the engine to the chattering phenomenon. In this study, structural analysis can be done by engine mounts designed with 3D modelling. Natural frequencies and harmonic responses are analyzed by using models with some kinds of configurations. When the simulation model is applied by the force of 600N within the range of natural frequencies, the magnitude of deformation becomes 0 to 3mm. As the number of holes around inside mount increases, the capability of vibration absorption and durability becomes larger. In case of 5holes around inside mount, it can be safest on durability. The life of mount becomes larger by changing the configuration of model. The engine mount improved with durability can be designed through the result of simulation.

• Computers and Concrete
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• 제14권6호
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• pp.727-743
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• 2014

The management of existing concrete bridges has become a major social concern in many developed countries due to the large number of bridges exhibiting signs of significant deterioration. This problem has increased the demand for effective maintenance and renewal planning. In order to implement an appropriate management procedure for a structure, a wide array of corrective strategies must be evaluated with respect to not only the condition state of each defect but also safety, economy and sustainability. This paper describes a new performance evaluation system for existing concrete bridges. The system evaluates performance based on load carrying capability and durability from the results of a visual inspection and specification data, and describes the necessity of maintenance. It categorizes all girders and slabs as either unsafe, severe deterioration, moderate deterioration, mild deterioration, or safe. The technique employs an expert system with an appropriate knowledge base in the evaluation. A characteristic feature of the system is the use of neural networks to evaluate the performance and facilitate refinement of the knowledge base. The neural network proposed in the present study has the capability to prevent an inference process and knowledge base from becoming a black box. It is very important that the system is capable of detailing how the performance is calculated since the road network represents a huge investment. The effectiveness of the neural network and machine learning method is verified by comparing diagnostic results by bridge experts.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.16-23
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• 2013

It is important that proving ground damage is correlated with target customer usage. This paper describes the test mode for durability test of active suspension control system for proving ground correlation and optimization. Acceleration, strain, wheel force and other types of data are collected on a vehicle as it traverses different proving ground surfaces. The primary objective of the analysis is to determine which mixture of proving ground surfaces offers the best representation of customer usage while minimizing the total test time. And durability testing offers the best way to assess the capability of a product to reach its reliability target. The test should be representative of the real environmental load and replicate the same customer usage.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.122-127
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• 2004

The purpose of this study is to introduce the standard of the durability and evaluation method for paper shredder. The major evaluation criteria include shredding capability, shredding blade (or cutter) hardness and edge roughness, and durability. Due to the difficulties in assessing the durability directly, performance deterioration of the shredder was assessed by measuring the torque variation along with the variation in shredded chip size and load, thereby proposing the indirect method of assessing the paper shredder durability.

• 한국생산제조학회지
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• 제19권3호
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• pp.376-380
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• 2010

The capability of automotive suspension system depends on steering safety of knuckle and lower control arm. In this study, light weight is applied with lower arm by the material of aluminium alloy. Distributed stress, fatigue life and proper vibration are analyzed with multiple loads happened by automobile. The durability of lower arm can be verified by the result of structural analysis.

• 항공우주시스템공학회지
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• 제14권6호
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• pp.10-17
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• 2020

The Korean medical evacuation helicopter was developed based on the Korean Utility Helicopter (hereafter referred to as 'Surion'). It uses an auxiliary power unit and engine for heating during winter operation. The helicopter maintains the internal temperature of the aircraft using its bleed air to satisfy its operational capability. However, due to the air inflow through the gap between the aircraft skin and door, additional heating for operating the portable medical equipment and preventing hypothermia in evacuated patients is required. Accordingly, an electric auxiliary heater was developed for additional heating during winter operation, and environmental, durability, and performance tests were conducted per MIL-STD-810G and MIL-STD-461F. The auxiliary heater was verified per the tailored airworthiness certification criteria.

• 한국전기전자재료학회논문지
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• 제36권1호
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• pp.81-87
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• 2023

Heaters using the resistance heating principle are used in various industrial fields that require heat and are also essentially used in bidet among small home appliances. A planar heater and a coil-inserted heater mounted on a conventional commercially used bidet have disadvantages and limitations of complicated manufacturing process and local heating. In this study, silver-palladium (Ag-Pd) powder material was used for a screen-printing process that is more advantageous in achieving simplification than the existing process, and a rod-type heater for bidet was manufactured. The on-off cycle test under actual conditions was conducted to confirm the durability and the capability of the fabricated heater, and the fabricated heater operated more than 2,600 on-off cycles, which means it could be applied for a commercial product. In addition, through the on-off cycles under harsh conditions, the cause of failure was identified after the test that the durability limit temperature of the heater was 850℃. Through Ag-Pd rod heater in this study, it is expected to contribute to the efficient development of electrode materials for heaters and the improvement of the durability of heaters in the future.