• 호남수학학술지
• /
• 제16권1호
• /
• pp.103-109
• /
• 1994

Piezoceramic patches as collocated actuator and sensors are widely used in mechanical control systems. An approximation scheme for computing feedback gains arising in heat flux stabilization problem with such control mechanism is introduced. The scheme is based on a finite element method and a variational approach.

• 대한수학회보
• /
• 제46권1호
• /
• pp.87-97
• /
• 2009

We prove the Hyers-Ulam stability of the sine and cosine functional equations in the spaces of generalized functions such as Schwartz distributions, Fourier hyperfunctions, and Gelfand generalized functions.

• 한국축산식품학회지
• /
• 제37권1호
• /
• pp.44-51
• /
• 2017

Heat treatment of milk aims to inhibit the growth of microbes, extend the shelf-life of products and improve the quality of the products. Heat treatment also leads to denaturation of whey protein and the formation of whey protein-casein polymer, which has negative effects on milk product. Hence the milk heat treatment conditions should be controlled in milk processing. In this study, the denaturation degree of whey protein and the combination degree of whey protein and casein when undergoing heat treatment were also determined by using the Native-PAGE and SDS-PAGE analysis. The results showed that the denaturation degree of whey protein and the combination degree of whey protein with casein extended with the increase of the heat-treated temperature and time. The effects of the heat-treated temperature and heat-treated time on the denaturation degree of whey protein and on the combination degree of whey protein and casein were well described using the quadratic regression equation. The analysis strategy used in this study reveals an intuitive and effective measure of the denaturation degree of whey protein, and the changes of milk protein under different heat treatment conditions efficiently and accurately in the dairy industry. It can be of great significance for dairy product proteins following processing treatments applied for dairy product manufacturing.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제10권3호
• /
• pp.117-128
• /
• 2002

This paper describes the smoke filling process of a fire field model based on a self-deve-loped SMEP (Smoke Movement Estimating Program) code to the simulation of fire induced flows in the two types of atrium space containing a ceiling heat flux. The SMEP using PISO algorithm solves conservation equations for mass, momentum, energy and species, together with those for the modified k-$\varepsilon$ turbulence model with buoyancy production term. Also it solves the radiation equation using the discrete ordinates method. Compressibility is assumed and the perfect gas law is used. Comparison of the calculated upper-layer average tempera-ture and smoke layer clear height with the zone models has shown reasonable agreement. The zone models used are the CFAST and the NBTC one-room. For atrium fires with ceiling glass the ceiling heat flux by solar heat causes a high smoke temperature near the ceiling. However, it has no effect on the smoke movement such as the smoke layer clear heights that are important in fire safety. In conclusion, the smoke layer clear heights that are important in evacuation activity except the early of a fire were not as sensitive as the smoke layer tem-perature to the nature of ceiling heat flux condition. Thus, a fire sensor in atrium with ceiling glass has to consider these phenomena.

• Structural Engineering and Mechanics
• /
• 제73권3호
• /
• pp.287-302
• /
• 2020

This investigation deals with a size-dependent coupled thermoelasticity analysis based on Green-Naghdi (GN) theory in nano scale using a new modified nonlocal model of heat conduction, which is based on the GN theory and nonlocal Eringen theory of elasticity. In the analysis based on the proposed model, the nonlocality is taken into account in both heat conduction and elasticity. The governing equations including the equations of motion and the energy balance equation are derived using the proposed model in a nano beam resonator. An analytical solution is proposed for the problem using the Laplace transform technique and Talbot technique for inversion to time domain. It is assumed that the nano beam is subjected to sinusoidal thermal shock loading, which is applied on the one of beam ends. The transient behaviors of fields' quantities such as lateral deflection and temperature are studied in detail. Also, the effects of small scale parameter on the dynamic behaviors of lateral deflection and temperature are obtained and assessed for the problem. The proposed GN-based model, analytical solution and data are verified and also compared with reported data obtained from GN coupled thermoelasticity analysis without considering the nonlocality in heat conduction in a nano beam.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집D
• /
• pp.240-245
• /
• 2001

Phenomena of direct contact condensation (DCC) heat transfer between steam and water are characterized by the transport of heat and mass through a moving steam/water interface. Application of the phenomena of DCC heat transfer to the engineering industries provides some advantageous features in the viewpoint of enhanced heat transfer. This study proposes a simple condensation model on the steam jets discharging into subcooled water from a single horizontal pipe for the prediction of the steam jet shapes. The analysis model was derived from the mass, momentum and energy equations as well as a thermal balance equation with condensing characteristics at the steam/water interface for the axi-symmetric coordinates. The extremely large heat transfer rate at the steam/water interface was reflected in the effective thermal conductivity estimated from the previous experimental results. The analysis results were compared with the experimental ones. The analysis model predicted that the steam jet shape (i. e. radius and length) was increasing as the steam mass flux and the pool temperature were increasing, which was similar in trend to that observed in the experiment.

• 한국습지학회지
• /
• 제10권1호
• /
• pp.21-30
• /
• 2008

증발산은 지표와 대기 사이에서 일어나는 에너지 상호작용에 기여하는 중요한 요소 중 하나이다. 갈대로 덮인 고흥만 간척지에서 현열, 토양열 그리고 순복사를 측정하여 증발산량을 조사하였다. 자동기상관측 자료로부터 산출된 증발산량은 구름과 바람의 연직경도가 $1s^{-1}$보다 미약한 경우를 제외하고 열수지 방정식으로 추정한 값과 잘 일치하였다. 토양열은 순복사의 약 10%로 평가되었다. 갈대로 구성된 식생캐노피 내에서 온도에 따른 포화수증기압의 변화율($${\Delta}{\sim_=}de_s/dT$$)이 약 1.5로 근사되었고, 증발산량은 순복사 에너지의 함수로 설명될 수 있다.

• 에너지공학
• /
• 제12권1호
• /
• pp.17-22
• /
• 2003

본 연구는 소형 CPL히트파이프의 제작 및 작동 특성에 대한 기초 지식을 얻기 위하여 수행되었다. CPL 히트파이프는 중력장 내에서 먼 거리까지 효과적으로 열을 이송할 수 있는 능력을 가지고 있다. 컴퓨터 칩에서 발생되는 열을 냉각하기 위하여 원판형 증발부로 구성된 소형 CPL을 설계 및 제작하여 그 작동 성능을 실험하였다. 두께 3mm, 직경 50mm의 원판형 청동 분발 소결 (equation omitted)를 사용하여 작동유체를 순환하기 위한 압력 구배를 얻을 수 있었으며 작동유체는 에탄올을 사용하였다. 실험은 응축부의 주위온도를 13$^{\circ}C$로 고정시킨 후 각각 다른 열부하에서의 CPL 작동 상태를 확인해 보았다.

• 한국화재소방학회논문지
• /
• 제16권2호
• /
• pp.8-13
• /
• 2002

유도가열 기술은 담금질, 단조를 위한 예열, 용융 그리고 요리 등과 같은 산업 전반에 걸쳐서 아주 폭넓게 사용되는 기술이다. 본 논문에서는 IH-JAR의 효과적인 설계를 위하여 자계 및 열 해석을 하였다. IH-lAR의 내부자계는 3차원 축대칭 유한요소법을 사용하여 해석하였으며, 열원은 IH-JAR 내부에서 유도된 와전류에 의하여 발생되고, 열은 열원과 열방정식을 사용하여 계산되어진다. 또한, IH-JAR의 온도분포를 시간과 투자율에 따라 제시하였다.

• 융복합기술연구소 논문집
• /
• 제5권1호
• /
• pp.1-5
• /
• 2015

SI thermochemical hydrogen production process achieves water splitting into hydrogen and oxygen through three chemical reactions. The process is comprised of three sections and one of them is HI decomposition into $H_2$ and $I_2$ called as Section III. The production of $H_2$ included processes involving EED for concentrating a product stream from Section I. Additionally an $I_2$ crystallization would be considered to reduce burden on EED by removing certain amount of $I_2$ out of a process stream prior to EED. In this study, the current thermodynamic model of SI process was briefly described and the calculation results of the applied Electrolytes NRTL model for phase equilibrium calculations was illustrated for ternary systems of Section III. We calculated temperature and heat duty of an $I_2$ crystallizer and heat duty of heaters using UVa model and heat balance equation of simulation tool. The results were expected to be used as operation information in optimizing HI decomposition process and setting up material balance throughout SI process.