• Title/Summary/Keyword: Heat transfer theory

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A Haptic Rendering Technique for 3D Objects with Vector Field (벡터 필드를 가진 3차원 오브젝트의 햅틱 렌더링 기법)

  • Kim, Lae-Hyun;Park, Se-Hyung
    • Journal of KIISE:Computer Systems and Theory
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    • v.33 no.4
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    • pp.216-222
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    • 2006
  • Vector field has been commonly used to visualize the data set which is invisible or is hard to explain. For instance, it could be used to visualize scientific data such as the direction and amount of wind and water field, transfer of heat through thermally conductive materials, and electromagnetic field. In this paper, we present a technique to enable intuitive recognition of the data though haptic feedback along with visual feedback. To add tactile information to graphical vector field, we model a haptic vector field and then apply it to the haptic map to guide a user to destination and haptic simulation of water field on 2D images whish can be used ill everyday life. These systems allow one to recognize vector information intuitively through haptic interface. We expect that the haptic rendering technique of vector field can be applied to various applications such as education, training, and entertainment.

A Study on the Variation of Temperature and the Deformation Characteristics in Asphaltic Concrete Pavement by Air Temperature (대기온도(大氣溫度)에 따른 아스팔트포장(鋪裝) 내부(內部) 온도변화(溫度變化)와 변형특성(變形特性)에 관(關)한 연구(硏究))

  • Kang, Min Soo;Kim, Soo Sam;Lee, Suk Keun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.5
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    • pp.1115-1128
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    • 1994
  • The condition of temperature gradients in asphaltic concrete (Ascon) pavement have been analyzed based on the data collected from 5 major sites in Korea. From this. considering heat transfer by insolation flux and air temperature within pavement slab. temperature variation on the surface of pavement was computed and numerical model using the theory of thermal conductivity was applied to estimate the temperature gradients in depth. To investigate the present condition of asphalt generally used in Korea. the asphalt property tests were applicated on 5 different AP-3 (AC 85~100), and AP-5 (AC 60~70) asphalts classified by penetration index. Uniaxial compression test and indirect tensile test were also carried out for varying temperature conditions to analyze the effect of temperature on the deformation characteristics of Ascon pavement by calculating the variation of static elastic modulus and layer coefficients.

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Study of the Internal Flow and Evaporation Characteristic Inside a Water Droplet on a Vertical Vibrating Hydrophobic Surface (수직 진동을 이용한 가열된 고체표면 위 증발하는 액적의 내부유동 제어연구)

  • Park, Chang-Seok;Lim, Hee-Chang
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.1
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    • pp.37-46
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    • 2017
  • Thermal Marangoni flow has been observed inside droplets on heated surfaces, finally resulting in a coffee stain effect. This study aims to visualize and control the thermal Marangoni flow by employing periodic vertical vibration. The variations in the contact angle and internal volume of the droplet as it evaporates is observed by using a combination of continuous light and a still camera. With regard to the internal velocity, the particle image velocimetry system is applied to visualize the internal thermal Marangoni flow. In order to estimate the internal temperature gradient and surface tension on the surface of a droplet, the theoretical model based on the conduction and convection theory of heat transfer is applied. Thus, the internal velocity increases with an increase in plate temperature. The flow directions of the Marangoni and gravitational flows are opposite, and hence, it may be possible to control the coffee stain effect.

An Analytic Study on Structural Stability according to Boundary Conditions and H-section Column Lengths Made of An Ordinary Grade Structural Steels (SS 400) at High Temperatures (일반구조용 강재(SS 400)기둥부재의 경계조건과 부재 길이변화에 따른 고온 내력의 해석적 연구)

  • Kwon, In-Kyu
    • Fire Science and Engineering
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    • v.28 no.1
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    • pp.20-25
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    • 2014
  • Steel column is very important an structural element in steel framed building and plays a key role in sustataining the applied external load. Generally, the fire resistance performance of steel column has been executed by application of fire standard and vertical furnace having a limitation in height. Therefore, the fire resistance test was conducted with a H-section column having 3500 mm in length and hinge to hinge boundary condition. And the fire protective material derived from the fire test can be applied to any kind of boundary conditions and lengths. However, it is hard to determine the fire resistance. In this paper, to make sure the structural stability of them at high temperature according to various boundary conditions and lengths of H-section column, an analysis was done by using the mechanical properties and an heat transfer theory.

The Effect of Mass Transfer on the Cure Properties of the Urea Resin Moulding Compounds Under the Drying Process (건조 공정 중 요소 수지 성형재료의 경화 특성에 대한 물질전달 효과)

  • Kim, Sang Yeul;Choi, Il Gon;Kim, Byoung Chul
    • Korean Chemical Engineering Research
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    • v.40 no.6
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    • pp.681-686
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    • 2002
  • In the industrial field, the theory of drying process is different from the practical application, and it is effective to reduce energy by recirculation of the heat of exhausting gas. But the study of this field may not be performed still. The cure properties of the urea resin moulding compounds was investigated according to drying temperature, drying time, recycle rate of exhausting gas and moulding temperature in the process of drying and moulding. We obtained the following results; water content of material decreases with increasing drying time and drying temperature, and the rate of drying also decreases with increasing recycle rate of exhausting gas. Specially, The cure fluidity of the urea resin moulding compounds decreases, with increasing drying temperature, recycle rate of exhausting gas and moulding temperature. And the correlation equations on water content and cure fluidity of the urea resin moulding material were obtained through a regression analysis of experimental data.

Evaluation of Structural Stability at High Temperature for H-section Beams Made of Ordinary Strength Steels by Analytic Method (일반 구조용 강재 적용 H형강 보부재의 해석에 의한 고온내력 평가 연구)

  • Kwon, In-Kyu
    • Fire Science and Engineering
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    • v.28 no.2
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    • pp.76-81
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    • 2014
  • Structural stability of structural beams at high temperature had been evaluated though a horizontal furnace and a standard fire curve. If a structural method and a material are satisfied with the fire test, those are seemed to be guaranteed the safety of residences, fire services men, and properties of the buildings. However, that requires not only longer period but higher cost for making and testing of each structural element. That restrained from developing new methods and new fire protective materials. In this study, an analytic method was executed to demonstrate whether the analytic method using mechanical properties of structural steel at high temperature with heat transfer theory works is working. In this paper, the surface temperature rising and variance of structural stability of a simple H-section beam with a standard fire curve were evaluated and structural stabilities of H-section beam according to differences from length of beam were suggested.

Genetic Analyses of Heading and Maturing Dates and Their Relationship to Freezing Resistance in Barley (보리 출수기와 성숙기의 유전분석 및 내동성과의 관계)

  • 천종은;강석원
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47 no.6
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    • pp.395-401
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    • 2002
  • The combination of early heading time, maturing time and short grain-filling period is very important to develop early varieties in winter barley. The 4 parental half diallel crosses (parents, $F_1$s, $F_2$s) were cultivated at the field. The heading date was from April 3 to 26, maturing date from May 15 to 27 and grain-filling period from 31 days to 42 days, showing that the varietal differences about the 3 traits were remarkable. According to half diallel cross analyses, Dongbori 1 for heading time (late heading) was dominant, but Oweolbori (early heading) was recessive, showing partial dominance with high additive component of genetic variance. Dongbori 1 for maturing time was dominant, but Oweolbori was recessive, showing partial dominance with high additive variance. Reno for grain-filling period (short grain-filling period) was dominant, but Oweolbori (long grain-filling period) was recessive with additive, and partial dominance. There were highly significant mean squares for both GCA and SCA effects on the heading and maturing times, and GCA/SCA ratios for all traits were high, showing the additive gene effects more important. Sacheon 6 and Oweolbori had greater GCA effects for early heading and maturing times, and Dongbori 1 and Reno had greater GCA effects for late times. GCA effects were highly significant in $F_1$ and $F_2$ generations, showing high GCA/SCA ratios (7.02). The heading and maturing times in field were positively correlated with antifreeze proteins concentrations, accumulation, resistance to photoinhibition and winter survival, respectively) but the grain-filling period did negatively correlated with the trails.

Effects of Salt Treatment on Yield and Physiological Characteristics of Flag Leaf at Heading Stage in Winter Barley (보리 출수기 염처리가 수량 및 지잎의 생리적 특성에 미치는 영향)

  • 최원열;김영민;박종환
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.47 no.6
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    • pp.409-412
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    • 2002
  • This research was conducted to obtain the fundamental data on salt injury and different responses among cultivars in winter barley (Hordeum vulgare L.). Salts did not affect yield components including number of panicles, stem length, grain number per ear and grain yield while reduced stem dry weight and thousand seed weight significantly with increasing concentrations of salt from 60 to 180 mM. NaCl had less injury effect on barley straw dry weight and thousand seed weight than did $MgSO_4$. Chlorophyll content and relative turgidity in flag leaf were reduced when treated with both salts, while free proline in the salt-treated leaf was increased. Content of proline in salt-treated barley was about 10 folds compared to the control. Based on yield components and physiological traits of flag leaf, the tolerance to salt injury was the greatest in Baegdong, followed by Dongbori#1, Mogpo#55, and Gangbori. The results suggested that salt- stressed barley at reproductive stage had higher free proline content, and that special management in this stage must be considered because salt stress at heading stage affect flag leaf growth as well as yield components Harmfully.