EXPERIMENTAL AND THEORETICAL INVESTIGATION ON THE INFLUENCE OF SURFACE EMISSIVITY ON THE THERMAL CONDUCTIVITY OF INSULATING MATERIALS

Micro/nano- BN co-doped epoxy composites were prepared and their thermal conductivity, breakdown strength at power frequency and voltage endurance time under high frequency bipolar square wave voltage were investigated. The thermal conductivity and breakdown performance were enhanced simultaneously in the composite with a loading concentration of 20 wt% BN at a micro/nano proportion of 95/5. The breakdown strength of 132 kV/mm at power frequency, the thermal conductivity of 0.81 W∙m−1∙K−1 and voltage endurance time of 166 s were obtained in the composites, which were approximately 28%, 286% and 349% higher than that of pristine epoxy resin. It is proposed that thermal conductive pathways are mainly constructed by micro-BN, leading to improved thermal conductivity and voltage endurance time. A model was introduced to illustrate the enhancement of the breakdown strength. The epoxy composites with high thermal conductivity and excellent breakdown performance could be feasible for insulating materials in high-frequency devices.

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Design and Implementation of a Laboratory Equipment for Studying Heat Transfer by Conduction

Műszaki Tudományos Közlemények ◽

10.33894/mtk-2019.11.34 ◽

2019 ◽

Vol 11 (1) ◽

pp. 153-156

Author(s):

István Padrah ◽

Judit Pásztor ◽

Rudolf Farmos

Keyword(s):

Heat Transfer ◽

Thermal Conductivity ◽

Heat Conduction ◽

Thermal Conduction ◽

Transfer Mechanism ◽

Measuring Instrument ◽

Heat Transfer Mechanism ◽

Laboratory Equipment ◽

Insulating Materials ◽

Design And Implementation

Abstract Thermal conduction is a heat transfer mechanism. It is present in our everyday lives. Studying thermal conductivity helps us better understand the phenomenon of heat conduction. The goal of this paper is to measure the thermal conductivity of various materials and compare results with the values provided by the manufacturers. To achieve this we assembled a measuring instrument and performed measurements on heat insulating materials.

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AN INVERSE METHOD APPLIED TO THERMAL CONDUCTIVITY MEASURMENT OF LIGHT INSULATING MATERIALS

Modern Physics Letters B ◽

10.1142/s0217984995001546 ◽

1995 ◽

Vol 09 (23) ◽

pp. 1539-1554 ◽

Cited By ~ 1

Author(s):

MICHELE CALI' ◽

VALTER GIARETTO ◽

GIUSEPPE RUSCICA

Keyword(s):

Thermal Conductivity ◽

Thermal Model ◽

Inverse Method ◽

Thermal Ageing ◽

Unsteady State ◽

Insulating Materials ◽

Experimental Apparatus ◽

Simplified Procedure

A simplified procedure for analyzing data obtained from an experimental apparatus in unsteady state conditions, constructed in order to measure thermal conductivity variations of light insulating materials obtained from thermal ageing and humidity cycles, is presented here. The calculations have been carried out with a lumped thermal model using an inverse method. Several ageing cycles and measurements have been carried out and the method has permitted the reduction of the experimental and calculation costs.

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Development of high-insulating materials with aerogel for protective clothing applications – an overview

International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde) ◽

10.1515/ijmr-2020-8042 ◽

2021 ◽

Vol 112 (2) ◽

pp. 164-172

Author(s):

Agnieszka Greszta ◽

Sylwia Krzemińska ◽

Grażyna Bartkowiak ◽

Anna Dąbrowska

Keyword(s):

Thermal Conductivity ◽

Thermal Insulation ◽

Protective Clothing ◽

State Of The Art ◽

Knitted Fabrics ◽

Insulating Materials ◽

Textile Materials ◽

Wide Range ◽

Properties Of Materials ◽

Hot Environments

Abstract Aerogels are ultra-light solids with extremely low thermal conductivity (even lower than air), thanks to which they have a huge potential in a wide range of applications. The purpose of this publication is to present the state-of-the art knowledge of the possibility of using aerogels to increase the thermal insulation properties of clothing materials intended for use in both cold and hot environments. Various methods of aerogels application to textile materials (non-woven, woven and knitted fabrics) are discussed, indicating their advantages and limitations. Numerous research studies confirm that aerogels significantly improve the thermal insulation properties of materials, but due to their delicate and brittle structure and their tendency to dusting, their application still poses considerable problems.

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