• 대한토목학회논문집
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• 제28권3A호
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• pp.391-399
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• 2008

강바닥판 포장에 사용되는 특수아스팔트 중의 하나인 구스아스팔트는 $240^{\circ}C$이상의 고온 상태에서 포설되기 때문에 시공중인 교량에 예상하지 못한 높은 온도와 이에 따른 열변형 및 열응력을 발생시킬 수 있다. 본 연구에서는 고온의 아스팔트 시공이 강바닥판에 미치는 열영향을 평가하고 이를 최소화하는 최적 포장공정을 찾기 위한 수치해석기법으로 등가열원을 이용한 열응력해석 기법을 제시하였다. 등가열원은 포장체 포설시의 열영향을 강상판 내부에서 발생하는 등가의 가상열원이다. 이를 이용하여 일반적인 구조해석 프로그램에서 구현하기 어려운 포장체의 포설에 의한 열전도, 열대류 등을 쉽게 모사할 수 있다. 포장 시공중 지점의 들림을 고려한 강상판 해석 및 다양한 포설 공정을 적용한 곡선교량해석을 통하여 등가열원방법의 적용성을 검토하였다.

• 열처리공학회지
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• 제17권1호
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• pp.17-22
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• 2004

In the present study, newly developed spark plasma sintering(SPS) technique was introduced to refine the grain size of ${\gamma}$-based TiAl intermetallic compounds. Ti-46Al-1.5Mo and Ti-46Al-1.5Mo-0.2C(at%) prealloyed powders were produced by mechanical milling(MM) in high-energy attritor. The mechanically milled powders were characterized by XRD and SEM for the microstructural evolution as a function of milling time. And then, the MMed powders were sintered by both spark plasma sintering and hot pressing in vacuum (HP). After the sintering process, MM-SPSed specimens were heat-treated in a vacuum furnace (SPS-VHT) and in the SPS equipment(MM-SPS) for microstructural control. It was found from microstrutural observation that the microstructure consisting of equiaxed ${\gamma}$-TiAl with a few hundred nanometer in average size and ${\alpha}_2-Ti_3Al$ particles were formed after both sintering processes. It was also revealed from hardness test and three-point bending test that the effect of grain refinement on the hardness and bending strength is much higher than that of carbon addition. The fully lamellar microstructures, which is less than $80{\mu}m$ in average grain size was obtained by SPS-VHT process, and the fully lamellar microstructure which is less than $100{\mu}m$ in average grain size was obtained by MM-SPS for a relatively shorter heat-treatment time.

• 한국재료학회지
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• 제30권9호
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• pp.489-494
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• 2020

SiC is a material with excellent strength, heat resistance, and corrosion resistance. It is generally used as a material for SiC invertors, semiconductor susceptors, edge rings, MOCVD susceptors, and mechanical bearings. Recently, SiC single crystals for LED are expected to be a new market application. In addition, SiC is also used as a heating element applied directly to electrical energy. Research in this study has focused on the manufacture of heating elements that can raise the temperature in a short time by irradiating SiC-I₂ with microwaves with polarization difference, instead of applying electric energy directly to increase the convenience and efficiency. In this experiment, Polydimethylsilane (PDMS) with 1,2 wt% of iodine is synthesized under high temperature and pressure using an autoclave. The synthesized Polycarbosilane (PCS) is heat treated in an argon gas atmosphere after curing process. The experimental results obtain resonance peaks using FT-IR and UV-Visible, and the crystal structure is measured by XRD. Also, the heat-generating characteristics are determined in the frequency band of 2.45 GHz after heat treatment in an air atmosphere furnace.

• Journal of Biosystems Engineering
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• 제17권1호
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• pp.5-17
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• 1992

To develop an analytic method of combustion characteristics in a small sized and single cylinder type diesel engine for a power tiller, 1) the theoritical analysis of combustion gas in engine cylinder was performed based on thermoscience and 2) the computer program which could be used to calculate those values of the apparent burning rate, the heat loss, the gas temperature and the fuel-air equivalence ratio with the experimental cylinder pressure data, was developed. This method would provide the practical and quantative data for the diesel combustion process. Through the use of this method, following details would be obtained: 1) the application in the modeling of combustion process without detail knowledeg of combustion process, 2) the basis for the complete modeling of diesel engine, and 3) the basic information for the design of combustion chamber by the prediction of engine performance.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.132-136
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• 2009

The importance and interests for saving of energy and cost in industry has been steadily grown up. Therefore, process optimization to reduce the processing step and energy is one of the most important things. The micro-alloyed steel of which post-heat-treatment is not necessary, has attractive points for high strength materials. However, for the application of non-heat-treated steel to structural parts, it is necessary to confirm the reliability of mechanical properties. In order to estimate mechanical properties. The microstructure, hardness, tensile strength, compressive strength and tensile fatigue strength of micro-alloyed steel having 900MPa tensile strength has been investigated.

• 대한기계학회논문집B
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• 제23권3호
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• pp.330-341
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• 1999

An experimental study for the two types of burners used in the non-oxidizing direct fired furnaces of the heat treatment process for the cold rolled plate has been carried out to investigate the combustion characteristics and the oxidization of the surface of steel plate. A steep temperature gradient and entrainment of residual oxygen were found near the heating surface in the flame of the nozzle mixing burner which has strong swirl velocity component. It was concluded that the elimination of the residual oxygen and the increase of the temperature of combustion gas on the heating surface are needed to enhance the performance of the burners for application to the non-oxidizing direct fired furnaces.

• 한국가금학회지
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• 제26권2호
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• pp.85-95
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• 1999

The mechanically deboned chicken meat(MDCM) has several limits in using for in using for in processed meat products as a main material because of poor color and textural properties, chance of microbial contamination and lipid oxidation. There has been a growing interest all over world in the application of MDCM to the surimi process. The surimi made from MDCM contains a high concentration of myofibrillar protein since this processing involves repeated washing processes with an aqueous solution in order to remove heme pigments, fat and other undesirable substances. The quality of the surimi made from MDCM is affected by various processing factors, such as kinds of wash solution, ion strength, washing cycle, temperature, pH changes, composition, part of muscle, particle size, and rigor state etc. A number of researchers havee investigated the effect of the various washing conditions on the properties of surimi gels. A fuller information of all the factors affecting surimi processing and gel formation by heat-induced gelation has not been known yet.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.186.1-186.1
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• 2011

Most of waste plastics including waste vinyls have been recycled up to about 50% of waste production, 4.5 million ton per year in 2009. To fundamentally increase the recycled amounts of waste plastics to waste production, the energy utilization of waste plastics is inevitable. But the contents of PVC included in waste plastics can limit the use as a RPF and make the air pollutants such as HCl and dioxin when it burns in the combustion system. Accordingly the source dechlorination by using heating method can be applied to make low contents of HCl as less than 0.6%. In this study the twin screw reactor using heat medium was used for the source dechlorination. As results of study, it was considered that this system is effective for the industrilal application.

• Journal of information and communication convergence engineering
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• 제12권2호
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• pp.104-108
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• 2014

The field of body sensor networks has attracted interest of many researchers due to its potential to revolutionize medicine. These sensors are usually implanted inside the human body and communicate among themselves. In the process of receiving, processing, or transmitting data, these devices produce heat. This heat damages the tissues surrounding the devices in the case of prolonged exposure. In this paper, to reduce this damages, we have improved and evaluated two protocols-the least temperature routing protocol and adaptive least temperature routing protocol-by implementing clustering as well as a leadership rotation algorithm. We used Castalia to simulate a basic body area network cluster composed of 6 nodes. A throughput application was used to simulate all the nodes sending data to one sink node. Simulations results shows that improved communication protocol with leadership rotation algorithm significantly reduce the energy consumption as compared to a scheme without leadership rotation algorithm.

• 열처리공학회지
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• 제11권3호
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• pp.200-206
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• 1998

The aim of this study is to investigate the effect of impurity level and fabrication processes on the strength, impact and fracture toughness of 7075, 7050 and 7175 aluminum alloy forgings. A specially processed 7175S-T74 aluminum forgings was superior to a conventionally processed 7075-T73, 7050-T74 and 7175-T74 aluminum forgings in both strength and toughness. The reduction of impurity level of iron and silicon has significantly diminished the size and volume fraction of second phase particles such as $Al_7Cu_2Fe$ and $Mg_2Si$. A further reduction of the amount of second phase particles has been observed by applying a special fabrication process. This phenomena result from the application of intermediate soaking at higher temperature and more sufficiant hot working temperature than that of a conventional processing.