• Title/Summary/Keyword: intrinsic insulation

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The Effect of Adjustable Garment Closures and Layering on Insulation in Cold Weather

  • Kim, Chil-Soon;McCullough, Elizabeth
    • Fashion & Textile Research Journal
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    • v.3 no.5
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    • pp.479-485
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    • 2001
  • This study was to determine the effect of garment closures and layering systems on insulation, using a thermal movable manikin in cold weather conditions. The insulation values of ensembles with opened and closed features were measured, and those of four different layered clothing ensembles were tested while standing and while walking. Our research indicated that when there was an opening involved in design the system, insulation decreased; even a zip-out lining in the armpit affected little. If a light weight jacket and pants are put on over a fleece shirt and pants instead polyester underwear, the amount of insulation increase was 0.43 clo.

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Development of Thermal Performance Tester for Non-Homogeneous Insulation Pannels Installed Vertically (수직으로 설치된 비균질 평판 단열재용 성능시험장치 개발)

  • Oh, Hong Young;Song, Ki O;Jeon, Hyun Ik;Cho, Sun Young
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.4
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    • pp.153-157
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    • 2016
  • In case of metal insulation, which is produced by stacking stainless steel sheets and air layers in a multi-stack manner at a specific thickness, insulation performance will be evaluated based on thermal transmittance rather than the intrinsic physical properties of each material such as thermal conductivity. However, there is no standard for measuring thermal transmittance targeted for non-homogeneous insulation which is used in relatively high temperature conditions such as a power station. In this study, the thermal conductivity of homogeneous insulation acquired by the standardized guard hot plate method and the thermal conductivity of homogeneous insulation measured by the newly developed performance tester were compared to verify the confidence level of the tester. As a result, thermal conductivity acquired by the newly developed thermal transmittance tester was about 6% higher than the thermal conductivity measured by the existing guard hot plate method under the anticipated service temperature conditions.

Study on the Electric Insulation Characteristics in a Fuel Cell Vehicle (연료전지 차량의 전기적 절연 특성에 관한 연구)

  • Yu, Jung-Han;kim, Duck-Whan;Kim, Ju-Han;Jeong, Kwi-Seong;Kum, Young-Bum;Kim, Sae-Hoon;Ahn, Deuk-Kuen
    • Journal of Hydrogen and New Energy
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    • v.23 no.2
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    • pp.150-155
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    • 2012
  • Polymer Electrolyte Membrane Fuel Cell (PEMFC) stack power output is needed to be approximately 100 kW to meet the requirements of automotive applications. In order to secure the electric safety for drivers, passengers and mechanics, it is very important to understand phenomena of an electric insulation in a fuel cell vehicle. In this study, we studied the electric insulation properties and the insulation resistance of stack, system and vehicle in the field of fuel cell was estimated at the applied voltage of 500 V, respectively. Also we discussed the insulation factors such as the conductivity of coolant, the element of vehicle design and the intrinsic resistance of the vehicle components.

A "Fabric-First" Approach to Sustainable Tall Building Design

  • Oldfield, Philip
    • International Journal of High-Rise Buildings
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    • v.6 no.2
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    • pp.177-185
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    • 2017
  • This research suggests the most effective way for improving energy efficiency in tall buildings is a "fabric-first" approach. This involves optimizing the performance of the building form and envelope as a first priority, with additional technologies a secondary consideration. The paper explores a specific fabric-first energy standard known as "Passivhaus". Buildings that meet this standard typically use 75% less heating and cooling. The results show tall buildings have an intrinsic advantage in achieving Passivhaus performance, as compared to low-rise buildings, due to their compact form, minimizing heat loss. This means high-rises can meet Passivhaus energy standards with double-glazing and moderate levels of insulation, as compared to other typologies where triple-glazing and super-insulation are commonplace. However, the author also suggests that designers need to develop strategies to minimize overheating in Passivhaus high-rises, and reduce the quantity of glazing typical in high-rise residential buildings, to improve their energy efficiency.

Ionic Passivation and Oxidation Dynamics for Enhanced Viability of Copper-Based On-Skin Bioelectrodes in Biological Environments

  • Jungho Lee;Gaeun Yun;Juhyeong Jeon;Phuong Thao Le;Seung Whan Kim;Geunbae Lim
    • Journal of Sensor Science and Technology
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    • v.32 no.6
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    • pp.352-356
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    • 2023
  • The integration of bioelectronic devices with the skin is a promising strategy for personalized healthcare monitoring and diagnostics. On-skin bioelectrodes hold great potential for the real-time tracking of physiological parameters. However, persistent challenges of stability and reliability have instigated exploration beyond conventional noble metals. This study focuses on the ionic passivation and oxidation dynamics of copper-based on-skin thin-film bioelectrodes. Through parylene chemical vapor deposition, we harness a controlled thin film of parylene insulation to counter the intrinsic susceptibility of copper to oxidation in the ionic environment. The results represent the relationship among the parylene insulation thickness, copper oxidation, and electrode impedance over temporal intervals. Comparative analyses indicate that the short-term stability of the copper electrode is comparable to that of the gold electrode. Therefore, we propose a cost-effective strategy for fabricating copper-based on-skin bioelectrodes by introducing enhanced ionic stability within a discernible operational timeframe. This study enriches our understanding of on-skin bioelectronics and affordable material choices for practical use in wearable healthcare devices.

Determining thermal comfort properties of coverall worn in the atomic power plant using a sweating thermal manikin and ISO 7730 (발한 Thermal manikin과 국제 표준 7730을 이용한 원자력 발전소 작업복의 열적 쾌적성 판별)

  • 홍성애
    • Journal of the Ergonomics Society of Korea
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    • v.15 no.1
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    • pp.91-103
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    • 1996
  • For determining thermal comfort properties of work suit in an atomic power plant, three different coverall ensembles (PVE, PET/Rayon, PP Nonwoven) were selected and the resistance to dry and evaporative heat transfer were measured for each ensemble by using a sweating thermal manikin. Also, PMV (Predicted Mean Vote) and PPD(Predicted Percentage of Dissatisfied) indices were predicted according to ISO 7730. As a result, ideal environmental conditions in an atomic power plant were suggested to make workers feel thermally comfortable. In addition, ideal intrinsic insulation values of coverall ensembles as a work suit under the present environmental conditions in the at6omic power plant were provided. The information given in this paper can be used to control environmental conditions in the atomic power plant thermally comfortable and to select a proper work suit for providing thermal comfort to the workers.

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Fabrication and Electrical Insulation Property of Thick Film Glass Ceramic Layers on Aluminum Plate for Insulated Metal Substrate (알루미늄 판상에 글라스 세라믹 후막이 코팅된 절연금속기판의 제조 및 절연특성)

  • Lee, Seong Hwan;Kim, Hyo Tae
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.4
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    • pp.39-46
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    • 2017
  • This paper presents the fabrication of ceramic insulation layer on metallic heat spreading substrate, i.e. an insulated metal substrate, for planar type heater. Aluminum alloy substrate is preferred as a heat spreading panel due to its high thermal conductivity, machinability and the light weight for the planar type heater which is used at the thermal treatment process of semiconductor device and display component manufacturing. An insulating layer made of ceramic dielectric film that is stable at high temperature has to be coated on the metallic substrate to form a heating element circuit. Two technical issues are raised at the forming of ceramic insulation layer on the metallic substrate; one is delamination and crack between metal and ceramic interface due to their large differences in thermal expansion coefficient, and the other is electrical breakdown due to intrinsic weakness in dielectric or structural defects. In this work, to overcome those problem, selected metal oxide buffer layers were introduced between metal and ceramic layer for mechanical matching, enhancing the adhesion strength, and multi-coating method was applied to improve the film quality and the dielectric breakdown property.

Improvement in Enzyme Immobilization of Polypyrrole Enzyme Electrode using Radical Transfer (Radical Transfer 반응을 이용한 Polypyrrole 효소전극의 효소고정화 향상)

  • Kim, Hyun-Cheol;Cho, Young-Jai;Gu, Hal-Bon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.04b
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    • pp.100-103
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    • 2000
  • In the case of immobilizing of glucose oxidase into polypyrrole (PPy) using electrosynthesis, the glucose oxidase (GOx) forms a coordinate bond with the polymers backbone. However, because of intrinsic insulation and net-chain of the enzyme, the charge transfer and mass transport are obstructed during the film growth. Therefore, the film growth is dull. We synthesized the enzyme electrode by electropolymerization added some organic solvent. A formative seeds of film growth is delayed by adding ethanol. The delay is induced by radical transfer between ethanol and pyrrole monomer. The radical transfer shares the contribution of dopant between electrolyte anion and GOx polyanion. This may lead to increase amount of immobilized the enzyme in PPy. For the UV absorption spectra of synthetic solution before synthesis and after, in the case of ethanol added, the optical density was slightly decreased for the GOx peaks. It suggests amount of GOx in the solution was decreased and amount of GOx in the film was increased. We established qualitatively that amount of immobilization can be improved by adding a little ethanol in the synthetic solution. It is due to radical transfer reaction. The radical transfer shares the contribution of dopant between small and fast electrolyte anion and big and slow GOx polyanion.

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Improvement on Enzyme Immobilization in Polypyrrole-Glucose Oxidase Enzyme Electrode using Organic Solvent Additive I. Ultraviolet Spectroscopic Analyses (유기용매 첨가에 따른 Polypyrrole-Glucose Oxidase 효소전극의 효소고정화 향상 I. 자외선 분광분석)

  • 김현철;구할본
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.7
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    • pp.615-620
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    • 2002
  • In the case of immobilizing of glucose oxidase into polypyrrole (PPy) using electrosynthesis, the glucose oxidise (GOx) forms a coordinate bond with the polymers backbone. However, because of intrinsic insulation and net-chain of the enzyme, the charge transfer and mass transport are obstructed during the film growth. Therefore, the film growth is dull. We synthesized enzyme electrodes by electropolymerization added some organic solvent, such as ethanol and tetrahydrofuran (THF). The formative seeds of film growth was delayed by adding ethanol. The delay was induced by radical transfer between ethanol and pyrrole monomer. The radical transfer reactions shared the contribution of dopants between electrolyte anion and GOx polyanion. This led to increase amount of immobilized the enzyme in PPy. For the UV absorption spectra of synthetic solution before synthesis and after, in the case of ethanol added, the optical density was slightly decreased for the GOx peaks. It suggests amount of GOx in the solution was decreased and amount of GOx in the film was increased.

Analysis of DC dielectric breakdown strength of Nano-composite insulation material for HVDC Cable (HVDC용 나노복합 절연재료의 DC절연파괴 분석)

  • Cho, Sung-Hoon;Jung, Eui-Hwan;Lee, Han-Ju;Lim, Kee-Joe;Jeong, Su-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.104-104
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    • 2010
  • With the advent of nano-particle fillers in insulating materials, the insulating materials of superior quality have come to fore. In the recent past, nanocomposite LDPE/XLPE (Low Density Polyethylene/Cross Linked Polyethylene) power cable dielectrics have been synthesized. A preliminary evaluation of these new class of materials seem to show that, addition of small amounts of sub-micron inorganic fillers improved the dielectric properties of the composite, in particular, the volume resistivity, and the DC breakdown strength. The thermal behaviour, for example, the stability of composites against decomposition and ensuing electrical failure, do not seem to have been addressed. In a conventional XLPE insulated cable, the average thermal breakdown strength and maximum temperature at the onset of breakdown were seen to be markedly lower than the corresponding intrinsic breakdown strength and decomposition temperature. In this page, analysis of DC Breakdown of nano-composite insulating material for HVDC Cable is introduced.

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