• Steel and Composite Structures
• /
• 제35권3호
• /
• pp.343-351
• /
• 2020

The present research deals with the multi-dual-phase-lags thermoelasticity theory for thermoelastic behavior of transversely isotropic thermoelastic thin circular plate The Laplace and Hankel transform techniques have been used to find the solution of the problem. The displacement components, stress components, and conductive temperature distribution are computed in the transformed domain with the radial distance and further determined in the physical domain using numerical inversion techniques. The effect of rotation and two temperature are depicted graphically on the resulting quantities.

• 대한기계학회논문집
• /
• 제13권2호
• /
• pp.271-276
• /
• 1989

본 실험에서는 액체연료인 석유와 등유을 사용하여 전도, 복사, 대류, 연료의 표면유동 등이 각각 어느 정도 화염확장에 영향을 주는 가를 예측하기 위하여 위의 각각을 제어할 수 있는 장애물을 설치하였으며, 연료의 깊이에 의한 화염확장의 영향을 알아보기 위하여 3가지 종류의 깊이에 대하여 실험을 수행하였다.

• Composite Materials and Engineering
• /
• 제3권3호
• /
• pp.241-262
• /
• 2021

In this article, we studied the effect of two-temperature in a two-dimensional orthotropic thermoelastic media with fractional order heat transfer in generalized thermoelasticity with three-phase-lags due to thermomechanical sources. The boundary of the surface is subjected to linearly distributed and concentrated loads (mechanical and thermal source). The solution of the problem is obtained with the help of Laplace and Fourier transform techniques. The expressions for displacement components, stress components and conductive temperature are derived in transformed domain. Numerical inversion technique is used to obtain the results in physical domain. The effect of two-temperature on all the physical quantities has been depicted with the help graphs. Some special cases are also discussed in the present investigation.

• Structural Engineering and Mechanics
• /
• 제81권5호
• /
• pp.529-537
• /
• 2022

The present research is to study the effect of inclined load in a two-dimensional homogeneous orthotropic magneto-thermoelastic solid without energy dissipation with fractional order heat transfer in generalized thermoelasticity with two-temperature. We obtain the solution to the problem with the help of Laplace and Fourier transformations. The field equations of displacement components, stress components and conductive temperature are computed in transformed domain. Further the results are computed in physical domain by using numerical inversion method. The effect of fractional order parameter and inclined load has been depicted on the resulting quantities with the help of graphs.

• Coupled systems mechanics
• /
• 제11권4호
• /
• pp.297-313
• /
• 2022

The objective of this paper is to study the effect of frequency in a two-dimensional orthotropic thermoelastic rotating solid with fractional order heat transfer in generalized thermoelasticity with two-temperature due to inclined load. As an application the bounding surface is subjected to uniformly and linearly distributed loads (mechanical and thermal source). The problem is solved with the help of Fourier transform. Assuming the disturbances to be harmonically time dependent, the expressions for displacement components, stress components, conductive temperature and temperature change are derived in frequency domain. Numerical inversion technique has been used to determine the results in physical domain. The results are depicted graphically to show the effect of frequency on various components. Some particular cases are also discussed in the present research.

• 대한기계학회논문집A
• /
• 제37권1호
• /
• pp.61-66
• /
• 2013

적층조형 방법의 개발로 열전도성 금형 혹은 형상적응형 냉각회로를 구비한 금형의 제작이 가능하게 되었다. 금형의 재질로 치수변화가 적은 P21 툴 스틸이 널리 사용되고 있지만, 열전도율이 낮기 때문에 냉각효율은 높지 않다. 이러한 점에서 열전달 효율을 극대화 시킬 수 있는 방법으로 P21 스틸과 구리(Cu)를 기능적으로 혼합한 기능성 경사 복합재(FGM)를 사용하는 방법이 검토되고 있다. 본 논문에서는 FGM 구조를 가지는 금형의 적층조형을 위한 예비연구로 P21-Cu 간의 1 차원 FGM 을 DMT 장비를 이용하여 제작하고, 열전달 관련 물성치를 평가하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
• /
• pp.652-652
• /
• 2013

The conventional thermal chemical vapor deposition (CVD) setup for the graphene synthesis has mainly used convective heat transfer in order to heat a catalyst (e.g. Cu) up to $1,000^{\circ}C$. Although the conventional CVD has been so far widely accepted as the most appropriate candidate enabling mass-production of high-quality graphene, this method has stillremained under the standard for the commercialization largely due to the poor productivity arisen out of the required long processing time. Here, we introduced a fast and efficient synthetic route toward CVD-graphene. Unlike the conventional CVD using convection heat transfer, we adopted a CVD setup utilizing conduction heat transfer between Cu catalyst and rapid heating source. The high thermal conductive nature of Cu and the employed rapid heating source led to the remarkable reduction in processing timeas compared to the conventional convection based CVD (Fig. 1A), moreover, the synthesized graphene was turned out to have comparable quality to that synthesized by the conventional CVD (Fig. 1B). For the optimization of the conduction based CVD process, the parametric studies were thoroughly performed using through Raman spectroscopy and electrical sheet resistance measurement. Our approach is thought to be worth considerable in order to enhance productivity of the CVD graphene in the industry.

• 한국수산과학회지
• /
• 제33권5호
• /
• pp.399-402
• /
• 2000

일반적인 수산물 통조림의 내용물 속에는 물, 기름 및 조미액즙 등 packing medium이 들어있다. 본 연구에서는 새우, 꽁치 및 굴을 원료로 건조 및 조미 후 packing medium이 없는 새로운 형태의 조미통조림을 제조하고 이들 제품의 진공도별 (15, 30, 45 및 60cmHg) 열침투 특성을 조사할 목적으로 본 연구를 수행하였다. 진공도별 제품의 열침투 속도는 진공도가 높을수록 빠르게 나타났으며 동일시간 살균했을 때 진공도가 높을수록 Fo치가 높게 나타났다. 한편 상법으로 제조된 water pack과 본 시험에서 제조한 조미통조림과의 열침투 속도를 비교했을 때 새우와 꽁치 조미통조림의 경우는 진공도 15cmHg 이상에서는 열침투 속도가 water pack 제품보다는 빠르게 나타났고 굴 제품의 경우는 water pack 제품이 30cmHg 이상에서 열침투 속도가 빠르게 나타났다. 따라서 packing medium이 없는 조미 통조림의 경우 진공도 30cmHg 이상이 되면 기존의 water pack 제품보다 열침투 속도가 빠르다는 사실이 관찰되었다.

• 전자통신동향분석
• /
• 제38권6호
• /
• pp.41-51
• /
• 2023

Heat dissipation technology for semiconductors and electronic packaging has a substantial impact on performance and lifespan, but efficient heat dissipation is currently facing limited improvement. Owing to the high integration density in electronic packaging, heat dissipation components must become thinner and increase their performance. Therefore, heat dissipation materials are being devised considering conductive heat transfer, carbon-based directional thermal conductivity improvements, functional heat dissipation composite materials with added fillers, and liquid-metal thermal interface materials. Additionally, in heat dissipation structure design, 3D printing-based complex heat dissipation fins, packages that expand the heat dissipation area, chip embedded structures that minimize contact thermal resistance, differential scanning calorimetry structures, and through-silicon-via technologies and their replacement technologies are being actively developed. Regarding dry cooling using single-phase and phase-change heat transfer, technologies for improving the vapor chamber performance and structural diversification are being investigated along with the miniaturization of heat pipes and high-performance capillary wicks. Meanwhile, in wet cooling with high heat flux, technologies for designing and manufacturing miniaturized flow paths, heat dissipating materials within flow paths, increasing heat dissipation area, and reducing pressure drops are being developed. We also analyze the development of direct cooling and immersion cooling technologies, which are gradually expanding to achieve near-junction cooling.

• 한국의류학회지
• /
• 제21권7호
• /
• pp.1153-1161
• /
• 1997

The insulation provided by clothing system is usually expressed in terms of a coo units and its distribution of the body, directly affect convective, conductive, and radiant heat loss from the skin to the environment Evaporated heat loss is dependent upon fabric permeability, the amount of body surface area covered by clothing, and the pumping of air between the body and garment layers. Persons at low to medium activity levels, dressed in conventional apparel in door environments, usually do not lose a large amount of heat through evaporation. Thermal manikin technology is used to measure the resistance to heat transfer provided by clothing systems. The reciprocal of this value, 6.45 W/m2.$^{\circ}C$ is often used in calculations for convenience. The purpose of this study was to implement a research program for calculation the insulation value (clo), body surface area and basal metabolic rate of selected clothing system. The project provided for the building of an insulation data base for use in evaluating and comparing new and improved garments.