• Resources Recycling
• /
• v.9 no.3
• /
• pp.37-45
• /
• 2000

This paper presents the experimental test results on moisture and freeze-thaw resistance of hot mix crumb rubber modified (CRM) asphalt concrete mixture. To compare the differences in mechanical properties of conventional and CRM asphalt concretes, various tests were conducted under different moisture conditions and freeze-thaw cycles. Marshall mix design was also performed to determine the optimum asphalt contents for the both asphalt concrete mixtures. Test results revealed that the moisture and freeze-thaw resistance of CRM asphalt mixture was superior to the conventional asphalt concrete. As a result, it is considered that the utilization of waste tires in asphalt pavements has the potential of minimizing the damage due to the moisture and freeze-thaw.

• Journal of the Korean Institute of Gas
• /
• v.7 no.2 s.19
• /
• pp.42-47
• /
• 2003

To prevent major accident from toxic gas release, explosion, or fire in chemical processes, it needs dynamic control of human error with mechanical failure. Although most of major accidents occur with a coupling of human error and mechanical failure, numbers of researches have studied human error and mechanical reliability independently, but no where cross each other, to reduce the risk in the process. This work focuses on the coincidence of human error and mechanical failure for management of human error, and on some important performance shaping factors to propose a method for improving safety effectively of the process industries.

• Journal of Korea Water Resources Association
• /
• v.36 no.1
• /
• pp.105-115
• /
• 2003

The computation model which evaluates combined hydraulic and mechanical reliability, is developed to analyze the integrated reliability in water distribution system. The hydraulic reliability is calculated by considering uncertain variables like water demand, hydraulic pressure, pipe roughness as random variables according to proper distribution type. The mechanical reliability is evaluated by analyzing the effect of pipe network with sequential failure of network components. The result of this study model applied to the real pipe network shows that this model can be used to simulate the uncertain factors effectively in real pipe network. Therefore, The pipe-line engineers can design and manage the network system with more quantitative reliability, through applying this model to reliable pipe network design and diagnosis of existing systems.

• Korean Journal of Materials Research
• /
• v.7 no.6
• /
• pp.453-459
• /
• 1997

용탕단조법에 의해 제조된 Mg-9AI-2Zn 합금을 미세조직관찰, 미소경도측정, 인장시험 등을 행하여 시효거동과 기계적 성질을 조사하였다. 용탕에 가압을 한 결과 주조결함이 제거된 미세한 주조조직을 얻었으며 미세조직은 초정 $\alpha$(Mg 고용체), 과포화고용체 $\alpha$상 및 $\beta$(Mg$_{17}$AI$_{12}$)화합물의 3가지 상으로 구성되어 있었다. 16$0^{\circ}C$및 20$0^{\circ}C$에서 시효열처리한 결과 $\beta$석출물에 의한 피크 경도값이 나타났으며 피크경도에서의 석출물의 형태는 lamella 형태의 불연속 석출물이 대부분이었고 과시효에 따라 불연속석출물의 조대화와 함께 연속석출물의 분율이 증가하였다. 용탕단조방법에 의해 제조된 Mg-9AI-2Zn 합금의 인장특성은 인장강도 261.4MPa, 연산율 7.6%로서 상용 AZ 92 합금보다 인장강도 및 연신율에서 우수한 기계적 성질을 가졌는데 이는 Zn의 고용강화 및 용탕의 가압에 의한 효과였다.다.

• Korean Journal of Materials Research
• /
• v.4 no.7
• /
• pp.823-827
• /
• 1994

The mechanical properties of diglycidyl ether of bisphenol A(DGEBA)/4,4- methylene dianiline(MDA) system with the addition of malononitrile(MN) and hydroquinone(HQ) were investigated. The specimens which were prepared by curing at $150^{\circ}C$ for lhr after curing at $80^{\circ}C$ for 1.5hr were tested. The effects of MN as a chain extender and HQ, a reaction accelerator on the mechanical properties were investigated. With the increase of MN and HQ contents, impact property improved significantly but tensile property decreased.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.9
• /
• pp.1099-1103
• /
• 2011

Since the mechanical strength and stiffness of wire-woven bulk Kagome (BK) have been theoretically estimated by assuming that WBK is composed of straight struts, the analytical solutions occasionally give substantial errors as compared with the experimental results. The struts of WBK are helically formed, which results in errors in the estimations In this study, for accurately predicting the mechanical properties of WBK, the effects of waviness and brazed part are taken into account for estimating the strength and stiffness of WBK. The results are compared with the measured experimental results and the results estimated by a finite element analysis performed on a unit cell under periodic boundary conditions (PBC).

• Applied Chemistry for Engineering
• /
• v.9 no.5
• /
• pp.715-718
• /
• 1998

In this work, bisphenol type vinyl ester was impregnated into the three-dimensional glass fabrics fabricated from different thickness changes. Their mechanical properties of the specimens have been investigated by three-point bending and flatwise compression tests. Also, interlaminar shear strength (ILSS) has been determined through short-beam test for the evaluation of interfacial adhesion at interfaces between fibers and matrix of the composites. The effect of thickness changes in three-dimensional glass fabric-reinforced composites have been described in this work.

• Korean journal of food and cookery science
• /
• v.19 no.4
• /
• pp.423-428
• /
• 2003

Jeungpyun was prepared with varying degrees of fermentation, and their effects on its quality characteristics were examined. In height and volume of jeungpyun, the samples treated with a first fermentation time of 240 minutes, and second and third fermentation times of 60 and 30 minutes, respectively (Sample E) had the best fermentation quality. A texture profile analysis, Hunter's color and sensory evaluation of these jeungpyun were carried out during the 4 days of storage. In the texture profile analysis, the hardness was observed to reduce in proportion to decreases in the fermentation time. The lightness value of Sample E showed one of the highest among the samples, but decreased as the storage time was prolonged. The results of the sensory evaluation showed that Jeungpyun of Sample E had higher swell, softness and moisture scores.

• Current Research on Agriculture and Life Sciences
• /
• v.31 no.3
• /
• pp.177-181
• /
• 2013

This study examined the effect of the molecular weight, substitution degree, and substitution type of cellulose ether on the mechanical properties of dried rice noodles. When increasing the molecular weight of the hydroxypropyl methylcellulose (HPMC), the bending strength of the dried rice noodles also increased. However, the bending strength of the rice noodles with added HPMCs was still lower than that of the wheat noodles. Meanwhile, the bending elongation of the dried rice noodles was higher than that of the wheat noodles and was increased when decreasing the molecular weight of the HPMC. In conclusion, the bending strength and elongation of dried rice noodles is affected by the substitution degree and type of cellulose ether.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.951-954
• /
• 2004

본 논문에서는 DLC(Diamond-like Carbon) 박막과 기판 사이에 금속층을 포함하는 DLC 박막의 기계적 특성을 분석하였다. 금속층은 sputtering법을 사용하고, DLC 박막은 PECVD법을 사용하여 각각 중착하였다. 티타늄(Ti), 니켄(Ni), 크롬(Cr)을 각 중간 금속층으로 사용한 후 DLC 박막과 실리콘(Si) 기판 간의 기계적 특성을 분석하였다. 각 막의 두께는 FE-SEM으로 확인하였고, DLC 박막의 구조 평가는 Raman spectrometer를 사용하여 분석하였으며, 각 금속층과 DLC 박막의 표면 상태는 AFM을 이용하여 확인하였다. XRD 분석을 통하여 박막의 격자분석을 하였고, SIMS(secondary ion mass spectrometry) 분석을 통하여 DLC 박막의 depth Profile을 확인하였다.