... Composites and Investigation on the Interaction Between Fiber and Epoxy Matrix Volkan C¸ ec¸ ... more ... Composites and Investigation on the Interaction Between Fiber and Epoxy Matrix Volkan C¸ ec¸ en, 1 Mehmet Sarikanat, 2 Hasan Yildiz, 2 Ismail H. Tavman 1 1Department of Mechanical Engineering, Dokuz Eylul University, 35100 Bornova, Izmir, Turkey ...
The aim of the experimental study is to determine thermal conductivity of composites as a functio... more The aim of the experimental study is to determine thermal conductivity of composites as a function of volume fraction and size of aluminum (Al) particles. High density polyethylene (HDPE) were filled with Al particles that have different particle sizes, 80 nm and 40-80 µm. Nanocomposites were prepared by the melt-mixing technique at various volume fractions (up to 33%). Thermal conductivity of polymer composites has been measured by C-Therm thermal analyzer depending on the modified transient plane source technique. Thermal conductivity of HDPE/Al composites increases by increasing volume fraction of Al in HDPE matrix. It is found that size of Al particles hasn't significant effect on thermal conductivity, thermal conductivity of HDPE/Al (80 nm) is close to thermal conductivity of HDPE/Al (40-80 µm).
The thermal conductivity and mechanical properties such as tensile strength, elongation at break,... more The thermal conductivity and mechanical properties such as tensile strength, elongation at break, modulus of elasticity, and toughness of composites formed by copper powder filler embedded in a high density poly(ethylene ) matrix are investigated experimerltally and the resuhs compared with existing theories. Thenual conductivity measttremcnts are perfnrmed up to a filler concentration of I0 vol,%. A modified hotwire technique is used to measure the thermal conductivity. The conductivity is best predicted by the Lewis and Nielsen model which takes into account the shape of the particles as well as the type of packing. The mechanical properties of high density poly(ethylene) tilled with up to 18 vol,% Cu particles arc investigated. The tensile strength, elongation at break and toughness decreased with increasing copper content, attribute,] to the introduction of discontinuities in the structure. The modulus of elasticity increased with increasing copper content,
Thermal conductivity of eleven kinds of cheese, four kinds of yogurt and a butter sample has been... more Thermal conductivity of eleven kinds of cheese, four kinds of yogurt and a butter sample has been measured at about 15°C and 30°C. A modi®ed hot wire method was used for thermal conductivity measurements. The eect of the water, fat and protein content on the thermal conductivity has been investigated, the measured thermal conductivity values were linearly dependent on water content, and inversely dependent on fat and protein contents of the various dairy products. A slight increase in the thermal conductivity with temperature has been noticed for four cheese samples studied over a wider range of temperature, between 4°C and 44°C. Ó 0260-8774/99/$ -see front matter Ó 1999 Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 0 -8 7 7 4 ( 9 9 ) 0 0 0 7 9 -5
Thermal conductivity and mechanical properties such as tensile strength, elongation at break, and... more Thermal conductivity and mechanical properties such as tensile strength, elongation at break, and modulus of elasticity of aluminum powder-filled high-density polyethylene composites are investigated experimentally in the range of filler content 0-33% by volume for thermal conductivity and 0-50% by volume for mechanical properties. Experimental results from thermal conductivity measurements show a region of low particle content, 0-12% by volume, where the particles are distributed homogeneously in the polymer matrix and are not interacting with each other; in this region most of the thermal conductivity models for two-phase systems are applicable. At higher particle content, the filler tends to form agglomerates and conductive chains resulting in a rapid increase in thermal conductivity. The model developed by Agari and Uno estimates the thermal conductivity in this region. Tensile strength and elongation at break decreased with increasing aluminum particles content, which is attributed to the introduction of discontinuities in the structure. Modulus of elasticity increased up to around 12% volume content of aluminum particles. Einstein's equation, which assumes perfect adhesion between the filler particles and the matrix, explains the experimental results in this region quite well. For particle content higher than 30%, a decrease in the modulus of elasticity is observed which may be attributed to the formation of cavities around filler particles during stretching in tensile tests. 0 1996 John
International Communications in Heat and Mass Transfer, 1998
The effective thermal conductivity of tin powder filled high density polyethylene composites is i... more The effective thermal conductivity of tin powder filled high density polyethylene composites is investigated experimentally as a function of filler concentration and the measured values are compared with the existing theoretical and empirical models. Samples are prepared by compression molding process, up to 16% volumetric concentration of tin particles. The thermal conductivity is measured by a modified hot wire technique in a temperature range from about 0°C to 70°C. Experimental results show a region of low particle content, up to about 10% volume concentration, where the increase in thermal conductivity is rather slow. The filler particles are dispersed in the matrix material in this region, the thermal conductivity is best predicted by Maxwell's model and Nielsen's model with A=I.5, d~m=0.637. Whereas, at high filler concentrations, the filler particles tend to form agglomerates and conductive chains in the direction of heat flow resulting in a rapid increase in thermal conductivity. A model developed by Agari and Uno estimates the thermal conductivity in this region, using two experimentally determined constants.
International Communications in Heat and Mass Transfer, 1997
In this study thermal diffusivity of two varieties of Triticum durum wheat and a wheat product, b... more In this study thermal diffusivity of two varieties of Triticum durum wheat and a wheat product, bulgur, is determined at different moisture contents and the results are compared with predictive models as well as with literature values. Thermal diffusivity is measured with transient heat conduction method which consists of placing a cylindrical sample in a constant temperature environment and recording the temperature at the center of the smnple with respect to time. If the surthce convective resistance is negligible, thermal diffusivity is determined from the timetemperature history and the dimensions of the sample. The measured thermal diffusivity values ranges between 8.92×I0 -s and l l.43×10-Sm2/s for Eregli, 8.76×10-Sand 10.78×10 -s m2/s for Saruhan and 8.28×10 -s m2/s for Bulgur. The results are in good agreement with literature values and close to Riedel and Martens models.
International Communications in Heat and Mass Transfer, 1996
ABSTRACT In this study, various conduction models for two-phase materials are considered and the ... more ABSTRACT In this study, various conduction models for two-phase materials are considered and the range of applicability of these models is discussed. Experimental work is carried out on construction sand of various grain size and different porosity in air at atmospheric pressure, and the results are compared with theoretical models. A modified hot-wire method is used in the measurement of effective thermal conductivities.
Purpose: In this study we report measurements of effective thermal conductivity by using 3ω metho... more Purpose: In this study we report measurements of effective thermal conductivity by using 3ω method and effective viscosity by vibro-viscometer for SiO 2 -water and Al 2 O 3 -water nanofluids at different particle concentrations and temperatures.
... Composites and Investigation on the Interaction Between Fiber and Epoxy Matrix Volkan C¸ ec¸ ... more ... Composites and Investigation on the Interaction Between Fiber and Epoxy Matrix Volkan C¸ ec¸ en, 1 Mehmet Sarikanat, 2 Hasan Yildiz, 2 Ismail H. Tavman 1 1Department of Mechanical Engineering, Dokuz Eylul University, 35100 Bornova, Izmir, Turkey ...
The aim of the experimental study is to determine thermal conductivity of composites as a functio... more The aim of the experimental study is to determine thermal conductivity of composites as a function of volume fraction and size of aluminum (Al) particles. High density polyethylene (HDPE) were filled with Al particles that have different particle sizes, 80 nm and 40-80 µm. Nanocomposites were prepared by the melt-mixing technique at various volume fractions (up to 33%). Thermal conductivity of polymer composites has been measured by C-Therm thermal analyzer depending on the modified transient plane source technique. Thermal conductivity of HDPE/Al composites increases by increasing volume fraction of Al in HDPE matrix. It is found that size of Al particles hasn't significant effect on thermal conductivity, thermal conductivity of HDPE/Al (80 nm) is close to thermal conductivity of HDPE/Al (40-80 µm).
The thermal conductivity and mechanical properties such as tensile strength, elongation at break,... more The thermal conductivity and mechanical properties such as tensile strength, elongation at break, modulus of elasticity, and toughness of composites formed by copper powder filler embedded in a high density poly(ethylene ) matrix are investigated experimerltally and the resuhs compared with existing theories. Thenual conductivity measttremcnts are perfnrmed up to a filler concentration of I0 vol,%. A modified hotwire technique is used to measure the thermal conductivity. The conductivity is best predicted by the Lewis and Nielsen model which takes into account the shape of the particles as well as the type of packing. The mechanical properties of high density poly(ethylene) tilled with up to 18 vol,% Cu particles arc investigated. The tensile strength, elongation at break and toughness decreased with increasing copper content, attribute,] to the introduction of discontinuities in the structure. The modulus of elasticity increased with increasing copper content,
Thermal conductivity of eleven kinds of cheese, four kinds of yogurt and a butter sample has been... more Thermal conductivity of eleven kinds of cheese, four kinds of yogurt and a butter sample has been measured at about 15°C and 30°C. A modi®ed hot wire method was used for thermal conductivity measurements. The eect of the water, fat and protein content on the thermal conductivity has been investigated, the measured thermal conductivity values were linearly dependent on water content, and inversely dependent on fat and protein contents of the various dairy products. A slight increase in the thermal conductivity with temperature has been noticed for four cheese samples studied over a wider range of temperature, between 4°C and 44°C. Ó 0260-8774/99/$ -see front matter Ó 1999 Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 0 -8 7 7 4 ( 9 9 ) 0 0 0 7 9 -5
Thermal conductivity and mechanical properties such as tensile strength, elongation at break, and... more Thermal conductivity and mechanical properties such as tensile strength, elongation at break, and modulus of elasticity of aluminum powder-filled high-density polyethylene composites are investigated experimentally in the range of filler content 0-33% by volume for thermal conductivity and 0-50% by volume for mechanical properties. Experimental results from thermal conductivity measurements show a region of low particle content, 0-12% by volume, where the particles are distributed homogeneously in the polymer matrix and are not interacting with each other; in this region most of the thermal conductivity models for two-phase systems are applicable. At higher particle content, the filler tends to form agglomerates and conductive chains resulting in a rapid increase in thermal conductivity. The model developed by Agari and Uno estimates the thermal conductivity in this region. Tensile strength and elongation at break decreased with increasing aluminum particles content, which is attributed to the introduction of discontinuities in the structure. Modulus of elasticity increased up to around 12% volume content of aluminum particles. Einstein's equation, which assumes perfect adhesion between the filler particles and the matrix, explains the experimental results in this region quite well. For particle content higher than 30%, a decrease in the modulus of elasticity is observed which may be attributed to the formation of cavities around filler particles during stretching in tensile tests. 0 1996 John
International Communications in Heat and Mass Transfer, 1998
The effective thermal conductivity of tin powder filled high density polyethylene composites is i... more The effective thermal conductivity of tin powder filled high density polyethylene composites is investigated experimentally as a function of filler concentration and the measured values are compared with the existing theoretical and empirical models. Samples are prepared by compression molding process, up to 16% volumetric concentration of tin particles. The thermal conductivity is measured by a modified hot wire technique in a temperature range from about 0°C to 70°C. Experimental results show a region of low particle content, up to about 10% volume concentration, where the increase in thermal conductivity is rather slow. The filler particles are dispersed in the matrix material in this region, the thermal conductivity is best predicted by Maxwell's model and Nielsen's model with A=I.5, d~m=0.637. Whereas, at high filler concentrations, the filler particles tend to form agglomerates and conductive chains in the direction of heat flow resulting in a rapid increase in thermal conductivity. A model developed by Agari and Uno estimates the thermal conductivity in this region, using two experimentally determined constants.
International Communications in Heat and Mass Transfer, 1997
In this study thermal diffusivity of two varieties of Triticum durum wheat and a wheat product, b... more In this study thermal diffusivity of two varieties of Triticum durum wheat and a wheat product, bulgur, is determined at different moisture contents and the results are compared with predictive models as well as with literature values. Thermal diffusivity is measured with transient heat conduction method which consists of placing a cylindrical sample in a constant temperature environment and recording the temperature at the center of the smnple with respect to time. If the surthce convective resistance is negligible, thermal diffusivity is determined from the timetemperature history and the dimensions of the sample. The measured thermal diffusivity values ranges between 8.92×I0 -s and l l.43×10-Sm2/s for Eregli, 8.76×10-Sand 10.78×10 -s m2/s for Saruhan and 8.28×10 -s m2/s for Bulgur. The results are in good agreement with literature values and close to Riedel and Martens models.
International Communications in Heat and Mass Transfer, 1996
ABSTRACT In this study, various conduction models for two-phase materials are considered and the ... more ABSTRACT In this study, various conduction models for two-phase materials are considered and the range of applicability of these models is discussed. Experimental work is carried out on construction sand of various grain size and different porosity in air at atmospheric pressure, and the results are compared with theoretical models. A modified hot-wire method is used in the measurement of effective thermal conductivities.
Purpose: In this study we report measurements of effective thermal conductivity by using 3ω metho... more Purpose: In this study we report measurements of effective thermal conductivity by using 3ω method and effective viscosity by vibro-viscometer for SiO 2 -water and Al 2 O 3 -water nanofluids at different particle concentrations and temperatures.
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