• Title/Summary/Keyword: heat transport

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A Study on the Slacks Materials for the Handicapped Children (지체장애아동의 하의소재에 관한연구)

  • 유화숙
    • Journal of the Korean Home Economics Association
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    • v.32 no.1
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    • pp.93-102
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    • 1994
  • The purpose of this study was to investigate the suitability of several knit fabrics for the hadicapped children's slacks. After the observation and wearing test abrasion resistance pilling liquid water transport properties and heat transport properties of the fabrics were tested. As specimens cotton/polypropylene interlock knits and sweat absorbent polyester knit fabric were selected and compared to the cotton denim and wool fabrics. As a result of observation test importance of extensibility durability and comfort related properties were recognized. Through the wearing test depending on the handicap type and orthoses different location and grade of pilling were observed. Knit fabrics used in this experiment were as durable as woven fabrics and showed excellent heat and liquid water transport properties. It was concluded therefore that cotton/polypropylene and sweat absorbent polyester knit fabrics are suitable materials for handicapped children's slacks.

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Coupled Turbulent Flow, Heat and Solute Transport in Continuous Casting Processes with EMBR (EMBR을 이용한 연속주조공정에서 난류 유동, 상변화 및 매크로 편석에 대한 연구)

  • Kang, Kwan-Gu;Ryou, Hong-Sun;Hur, Nahm-Keon
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1195-1200
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    • 2004
  • A fully coupled fluid flow, heat, and solute transport model was developed to investigate turbulent flow, solidification, and macrosegregation in a continuous casting process of steel slab with EMBR. Transport equations of mass, momentum, energy, and species for a binary iron-carbon alloy system were solved using a continuum model. The electromagnetic field was described by the Maxwell equations. A finite-volume method was employed to solve the conservation equations associated with appropriate boundary conditions. The effects of intensity of magnetic field and carbon segregation were investigated. The electromagnetic field reduces the velocity of molten flow in the mold and an increase in the percentage of C in steel results in a decrease of carbon segregation ratio.

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The Heat Transfer Characteristics Analysis of Rotary Kiln for Scale Up (로터리 킬른 스케일 업을 위한 열전달 특성 고찰)

  • Eum, Minje;Choi, Sangmin
    • 한국연소학회:학술대회논문집
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    • 2012.04a
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    • pp.97-98
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    • 2012
  • The rotary kiln is one of the most widely used industrial reactors for contacting gases and solids. Kilns are mainly used for drying, calcining and reducing solid materials. In an indirected fired rotary kiln, heat is supplied to the outside of the kiln wall. Heat transfer in indirected fired rotary kilns encompasses all the modes of transport mechanisms, that is, conduction, convection and radiation. This paper deal with the heat transfer characteristics of indirect fired rotary kiln for scale up.

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Effect of heat treatment of digestion-resistant fraction from soybean on retarding of bile acid transport in vitro

  • Han, Sung-Hee;Lee, Seog-Won;Rhee, Chul
    • Nutrition Research and Practice
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    • v.3 no.2
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    • pp.149-155
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    • 2009
  • In this study, we investigated the heat effect of digestion-resistant fraction (RF) from soybean on retarding bile acid transport in vitro. The RFs from soybean retarded bile acid transport. A raw, unheated RF of soybean (RRF-SOY) was significantly more effective than the heated RF of soybean (HRF-SOY). The RS1 which physically trapped in milled grains and inaccessible to digestive enzyme after 18 hrs incubation level of content in RRF-SOY was found to be as high as 24.1% and after heating the RS1 of HRF-SOY was significantly reduced to 16.8%. The X-ray diffraction pattern of RF from soybean was altered after heat treatment. The RFs from soybean were characterized by peak at diffraction angles of $12.0^{\circ}$ and $20.0^{\circ}$ corresponding to RS content. Cellulose contents of RRF-SOY was 5% higher than that of HRF-SOY and pentosan contents of RRF-SOY was 5% higher than that of HRF-SOY, too. Whereas the hemicellulose content of RRF-SOY was 13% lower than HRF-SOY.

Failure Analysis of Stress Reliever in Heat-Transport Pipe of District Heating System

  • Cho, Jeongmin;Chae, Hobyung;Kim, Heesan;Kim, Jung-Gu;Kim, Woo Cheol;Lee, Soo Yeol
    • Corrosion Science and Technology
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    • v.21 no.4
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    • pp.243-249
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    • 2022
  • The objective of the present study was to perform failure analysis of double-layered bellow (expansion joint), a core part of stress reliever, used to relieve axial stresses induced by thermal expansion of heat-transport pipes in a district heating system. The bellow underwent tensile or compressive stresses due to its structure in terms of position. A leaked position sufferred a fatigue with a tensile component for decades. A cracked bellow contained a higher fraction of martensitic phase because of manufacturing and usage histories, which induced more brittleness on the component. Inclusions in the inner layer of the bellow acted as a site of stress concentration, from which cracks initiated and then propagated along the hoop direction from the inner surface of the inner layer under fatigue loading conditions. As the crack reached critical thickness, the crack propagated to the outer surface at a higher rate, resulting in leakage of the stress reliever.

Corrosion Protective Method Applicable to Air Vent Connected with a Heat Transport Pipe (열수송관에 연결된 에어벤트에 적용 가능한 부식 방지 방안)

  • Min Ji Song;Gahyun Choi;Woo Cheol Kim;Soo Yeol Lee
    • Corrosion Science and Technology
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    • v.22 no.2
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    • pp.115-122
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    • 2023
  • This study aimed to elucidate causes of corrosion of heat transport pipes and air vents installed under a manhole of heat transport facilities and suggest effective anticorrosive measures by applying paints or adhesive tapes. It was found that air vent corrosion was attributed to corrosion under insulation caused by the inflow of water and the enrichment of chloride ions. The infiltrated water caused a hydrolysis of polyurethane foam (PUF) insulation by concentrating chloride ions at the interface between a pipe and the PUF. As insulator deteriorated, more chloride ions were eluted as confirmed by ion chromatograph (IC) analysis. As an effective method to prevent air vent corrosion, different types of paints and adhesive tapes with higher corrosion resistance on chloride ions were applied and environmental resistance tests were performed with those samples. Based on environmental test results of samples exposed to 10% HCl solution, it was revealed that a wax tape was the most adequate from a viewpoint of stability at operating condition, environmental resistance, surface treatment, and field applicability.

A Theoretical Study on the Feasibility of Long Distance Heat Transport Network Using Decomposition/Synthesis of Methanol (메탄올의 분해/합성 반응을 이용한 장거리 열수송 네트웤 구축 가능성에 대한 이론적 연구)

  • Jang, In-Sung;An, Ik-Kyoun;Han, Gui-Young;Moon, Seung-Hyun;Park, Sung-Youl;Park, Min-A;Lee, Hoon;Yoon, Seok-Mann
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 2007.11a
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    • pp.187-192
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    • 2007
  • A project is being implemented to develop the long distance energy transport technology using the chemical reactions. This project can be classified into three main research categories covering heat recovery reaction, long distance energy transport, and heat generation reaction. In this study, the methanol is selected as a system material since it shows several unique superior characteristics as follows: gaseous state of reactant and product, large heat of reaction, high yields of reaction at relatively low temperature, and also steady and economical supply. Furthermore, it is anticipated that the outcomes of this study can be widely applied to the related industries. A feasibility study was carried out to evaluate the economics of this technology which study was based on the following case: 10,000 households, 15km distance energy transportation, utilization of waste heat from power plant.

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Chinese Medicine Granule Affects the Absorption and Transport of Glucose in Porcine Small Intestinal Brush Border Membrane Vesicles under Heat Stress

  • Song, Xiaozhen;Xu, Jianqin;Wang, Tian;Liu, Fenghua
    • Asian-Australasian Journal of Animal Sciences
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    • v.22 no.2
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    • pp.246-253
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    • 2009
  • This study was conducted to investigate the effects of Chinese medicine granule (CMG, including Cortex Phellodendron, Atractylodes Rhizome, Agastache Rugosa and Gypsum Fibrosum) on absorption and transport of glucose in porcine small intestinal brush border membrane vesicles (BBMVs) under heat stress. Forty-eight 2-month-old Chinese experimental barrows were screened according to weight and litter origin, and then allotted to three groups and treated as follows: Normal temperature control group (NTCG; $23^{\circ}C$), high temperature control group (HTCG; $26^{\circ}C$ for 19 h, $40^{\circ}C$ for 5 h); Chinese medicine granule anti-stress group (CMGG; $26^{\circ}C$ for 19 h, $40^{\circ}C$ for 5 h) (n = 16 per group). The results showed that high temperature treatment decreased (p<0.05) the growth performance and intestinal glucose absorption but there was no change (p>0.05) in the expression of SGLT1 and GLUT2 genes in the small intestine of pigs compared with the NTCG. Dietary supplementation with CMG improved the growth performance, and increased the activity of disaccharidases in duodenum and jejunum of heat stressed pigs (p<0.05). CMG treatment increased (p<0.05) the protein levels of SGLT1 and GLUT2 in the small intestine, and up-regulated (p<0.05) the expression of SGLT1 and GLUT2 genes in the duodenum and jejunum but without changing (p>0.05) them in the ileum compared with the HTCG. These results indicated that CMG treatment significantly improved porcine growth performance, and increased intestinal glucose absorption and transport by BBMVs under heat stress, in addition to up-regulating the expression of SGLT1 and GLUT2 genes in porcine duodenum and jejunum.

Silicon melt motion in a Czochralski crystal puller (쵸크랄스키 단결정 장치에서의 실리콘유동)

  • 이재희;이원식
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.7 no.1
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    • pp.27-40
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    • 1997
  • The heat in Czochralski method is transfered by all transport mechanisms such as convection, conduction and radiation and convection is caused by the temperature difference in the molden pool, the rotations of crystal or crucible and the difference of surface tension. This study delvelops the simulation model of Czochralski growth by using the finite difference method with fixed grids combined with new latent heat treatment model. The radiative heat transfer occured in the surfce of the system is treated by calculating the view factors among surface elements. The model shows that the flow is turbulent, therefore, turbulent modeling must be used to simulate the transport phenomena in the real system applied to 8" Si single crystal growth process. The effects of a cusp magnetic field imposed on the Czochralski silicon melt are studied by numerical analysis. The cusp magnetic field reduces the natural and forced convection due to the rotation of crystal and crucible very effectively. It is shown that the oxygen concentration distribution on the melt/crystal interface is sensitively controlled by the change of the magnetic field intensity. This provides an interesting way to tune the desired O concentration in the crystal during the crystal growing.

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Estimating groundwater recharge from time series measurements of subsurface temperature

  • Koo, Min-Ho;Kim, Yongje
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.09a
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    • pp.213-216
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    • 2003
  • Efforts for better understanding of the interaction between groundwater recharge and thermal regime of the subsurface medium is gaining momentum for its diverse applications in water resources. A numerical model is developed to simulate temperature variations of the subsurface under time varying groundwater recharge. The model utilizes MacCormack scheme for finite difference approximation of the partial differential equation describing the conductive and advective heat transport. For the estimation of recharge rate, optimization of the model is realized by searching for the unknown parameters which minimize the root-mean-square error between simulated and measured temperatures. Simulation results for 22-year time series data of temperature measurements reveal that the proposed model can accurately simulate subsurface temperature variations resulting from the redistribution of the heat due to the movement of water and it can also estimate temporal variations of recharge. Seasonal variations of recharge and a linear relationship between precipitation and recharge are clearly reflected in the simulated results.

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