The Experts below are selected from a list of 7389 Experts worldwide ranked by ideXlab platform
D. Mullen - One of the best experts on this subject based on the ideXlab platform.
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recent developments of lightweight high performance heat pipes
Applied Thermal Engineering, 2012Co-Authors: Xu Yang, D. MullenAbstract:Abstract Heat pipes, known as “super Thermal Conductors” have been widely used in many areas for more than 50 years. Currently, due to the various requirements put on cooling systems, such as lightweight, better heat transfer performance, and optimised appearance, heat pipes have been improved significantly in the past decades. This paper summarises the recent developments of lightweight, high performance heat pipes. Various methods or approaches to achieve the requirements of lightweight and high performance are introduced. The applications of lightweight materials can help reduce by up to 80% the weight of conventional copper heat pipes; however the lightweight material often has problems of corrosion. Although improving the design of wick structures and changing the size of conventional heat pipe assemblies can help to reduce weight and achieve high heat flux, there are still some limitations to the applications of lightweight materials such as magnesium due to its incompatibility with some working fluids.
K G Ang - One of the best experts on this subject based on the ideXlab platform.
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micro drilling of alumina green bodies with diamond grit abrasive micro drills
International Journal of Machine Tools & Manufacture, 2003Co-Authors: Dai Gil Lee, Hak Gu Lee, P J Kim, K G AngAbstract:Since ceramic plates containing many micro-holes are used for MCPs (Micro-channel plates) for electron amplification, catalytic converters, filters, electrical insulators and Thermal Conductors in integrated circuits, the efficient drilling of micro-holes in ceramic plates is important for productivity and cost. Since ceramics have poor machinability due to their low Thermal conductivity, high hardness and high brittleness, in this work, alumina green bodies rather than sintered alumina were drilled to manufacture ceramic MCPs, followed by sintering the machined green bodies. Alumina green bodies were drilled with electro-deposited diamond grit WC micro-drills, and the cutting force with respect to drilling time was measured to determine a suitable micro-drilling condition. From the measurement of the micro-drill tip wear during micro-drilling of alumina green bodies, a model for the cutting force during micro-drilling was constructed.
Michel W Barsoum - One of the best experts on this subject based on the ideXlab platform.
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transport, Thermal transport, and elastic properties of M2AlC (M=Ti
2020Co-Authors: J D Hettinger, S E Lofland, Peter Finkel, T Meehan, J Palma, K Harrell, S Gupta, A Ganguly, T El-raghy, Michel W BarsoumAbstract:In this paper we report on a systematic investigation, in the 5 to 300 K temperature regime, of the electronic, magnetotransport, thermoelectric, Thermal, and elastic properties of four M 2 AlC phases: Ti 2 AlC, V 2 AlC, Cr 2 AlC, and Nb 2 AlC. The electrical conductivity, Hall coefficient, and magnetoresistances are analyzed within a two-band framework assuming a temperature-independent charge carrier concentration. As with other MAX-phase materials, these ternaries are nearly compensated, viz. the densities and mobilities of electrons and holes are almost equal. There is little correlation between the Seebeck and Hall coefficients. With Young's and shear moduli in the 270 GPa and 120 GPa range, respectively, the phases studied herein are reasonably stiff. With room temperature Thermal conductivities in the 25 W / m K range ͑45 W / m K for V 2 AlC͒ they are also good Thermal Conductors
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electrical transport Thermal transport and elastic properties of m2alc m ti cr nb and v
Physical Review B, 2005Co-Authors: J D Hettinger, S E Lofland, Peter Finkel, T Meehan, J Palma, K Harrell, S Gupta, A Ganguly, T Elraghy, Michel W BarsoumAbstract:In this paper we report on a systematic investigation, in the 5 to 300 K temperature regime, of the electronic, magnetotransport, thermoelectric, Thermal, and elastic properties of four M2AlC phases: Ti2AlC, V2AlC, Cr2AlC, and Nb2AlC. The electrical conductivity, Hall coefficient, and magnetoresistances are analyzed within a two-band framework assuming a temperature-independent charge carrier concentration. As with other MAX-phase materials, these ternaries are nearly compensated, viz. the densities and mobilities of electrons and holes are almost equal. There is little correlation between the Seebeck and Hall coefficients. With Young’s and shear moduli in the 270 GPa and 120 GPa range, respectively, the phases studied herein are reasonably stiff. With room temperature Thermal conductivities in the 25 W/m K range 45 W/m K for V2AlC they are also good Thermal Conductors.
Chih-wei Chang - One of the best experts on this subject based on the ideXlab platform.
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Probing the limit of one-dimensional heat transfer under extreme bending strain
Physical Review B, 2013Co-Authors: Renkun Chen, Chih-wei ChangAbstract:Theoretically, when a one-dimensional (1D) ballistic Thermal conductor is mechanically bent beyond its elastic limit, nonlinear structural buckling will develop and reduce the transmission of phonons. However, because of limited mechanical strengths and short phonon mean free paths of most materials, no experimental works are capable of testing this fundamental limit of heat transfer so far. Here, we utilize the superior mechanical strength and the high Thermal conductivity of single-wall carbon nanotubes (SWCNTs) to investigate the heat transfer phenomena at a previously inaccessible experimental regime. Surprisingly, even when the SWCNTs are bent far beyond their critical angles and curvatures, their Thermal conductivities remain intact under cyclic bending. Moreover, the observed robustness of heat transfer is found to be independent of structural kinks, defects, dislocations, bending angles, or curvatures. Our results demonstrate that SWCNTs are exceptional 1D Thermal Conductors capable of sustaining high transmission of phonons under extreme bending strain.
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breakdown of fourier s law in nanotube Thermal Conductors
Bulletin of the American Physical Society, 2007Co-Authors: Chih-wei Chang, H. Garcia, A. Majumdar, David Okawa, A ZettlAbstract:C.W. Chang,* D. Okawa, H. Garcia, A. Majumdar, and A. Zettl Department of Physics, University of California at Berkeley, California 94720, USA Center of Integrated Nanomechanical Systems, University of California at Berkeley, California 94720, USA Departments of Mechanical Engineering and Materials Science and Engineering, University of California at Berkeley, California 94720, USA Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA (Received 11 March 2008; revised manuscript received 9 July 2008; published 15 August 2008)
Xiaopeng Huang - One of the best experts on this subject based on the ideXlab platform.
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Nanostructured polymer films with metal-like Thermal conductivity.
Nature Communications, 2019Co-Authors: Y. Xu, Daniel Kraemer, James Loomis, B Song, Hadi Ghasemi, Z. Jiang, Jiawei Zhou, Jianjian Wang, Mingda Li, Xiaopeng HuangAbstract:Due to their unique properties, polymers – typically Thermal insulators – can open up opportunities for advanced Thermal management when they are transformed into Thermal Conductors. Recent studies have shown polymers can achieve high Thermal conductivity, but the transport mechanisms have yet to be elucidated. Here we report polyethylene films with a high Thermal conductivity of 62 Wm−1 K−1, over two orders-of-magnitude greater than that of typical polymers (~0.1 Wm−1 K−1) and exceeding that of many metals and ceramics. Structural studies and Thermal modeling reveal that the film consists of nanofibers with crystalline and amorphous regions, and the amorphous region has a remarkably high Thermal conductivity, over ~16 Wm−1 K−1. This work lays the foundation for rational design and synthesis of Thermally conductive polymers for Thermal management, particularly when flexible, lightweight, chemically inert, and electrically insulating Thermal Conductors are required. Thermally conductive polymers can be used for advanced Thermal management applications but the transport mechanisms have yet to be elucidated. Here the authors report the synthesis of polyethylene films with high Thermal conductivity, which is attributed to the amorphous regions of the nanofibers.