Thermal Characterization of Silicon Carbide Nanowire Films

2008 ◽  
Author(s):  
Eduardo Castillo ◽  
Sadia Choudhury ◽  
Hyun Woo Shim ◽  
Jaron Kuppers ◽  
Hanchen Huang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Silicon Oxide ◽  
Thermal Contact ◽  
Thermal Characterization ◽  
Intrinsic Structure ◽  
Low Thermal Conductivity ◽  
Sic Nanowires ◽  
Thermal Measurements ◽  
Single Crystal Sic

This paper reports on thermal characterization of SiC nanowire films on alumina substrate. The SiC nanowires films were synthesized via carbothermal reduction by thermal evaporation of silica and graphite powders using a high temperature alumina tube furnace. Structural characterization showed that nanowires have a core-shell structure, with a core of single crystal SiC of ∼50 nm in diameter and an amorphous shell of silicon oxide of ∼10 nm in thickness. Prior thermal measurements as-deposited SiC nanowires were compacted into more dense films via capillary coalescence. The effective thermal conductivity in the direction perpendicular to the film was determined employing a steady-state experimental method in conjunction with one-dimensional heat transfer modeling. Preliminary results suggest that these films have a very low thermal conductivity, in the range of 0.1W/mK. The low thermal conductivity may be due to intrinsic structure of the nanowire film such as porosity and large number of interfaces between the SiC nanowire core and its outer oxide layer as well as thermal contact resistance at nanowires junctions.

scholarly journals Thermal Characterization of Phantoms Used for Quality Assurance of Deep Hyperthermia Systems

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4549
Author(s):  
Laura Farina ◽  
Kemal Sumser ◽  
Gerard van Rhoon ◽  
Sergio Curto
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Characterization ◽  
Sensitivity Study ◽  
Volumetric Heat Capacity ◽  
Internal Organs ◽  
Protocol Optimization ◽  
Thermal Measurements ◽  
Deep Hyperthermia

Tissue mimicking phantoms are frequently used in hyperthermia applications for device and protocol optimization. Unfortunately, a commonly experienced limitation is that their precise thermal properties are not available. Therefore, in this study, the thermal properties of three currently used QA phantoms for deep hyperthermia are measured with an “off-shelf” commercial thermal property analyzer. We have measured averaged values of thermal conductivity (k = 0.59 ± 0.07 Wm−1K−1), volumetric heat capacity (C = 3.85 ± 0.45 MJm−3K−1) and thermal diffusivity (D = 0.16 ± 0.02 mm2s−1). These values are comparable with reported values of internal organs, such as liver, kidney and muscle. In addition, a sensitivity study of the performance of the commercial sensor is conducted. To ensure correct thermal measurements, the sample under test should entirely cover the length of the sensor, and a minimum of 4 mm of material parallel to the sensor in all directions should be guaranteed.

Evaluation of Thermal Characterization Techniques and Tools for Thermal Conductivity Measurement of Sub 100 Angstrom Thick Silicon Layers

2007 ◽  
Author(s):  
Keivan Etessam-Yazdani ◽  
Mehdi Asheghi
Keyword(s):  
Thermal Conductivity ◽  
Conductivity Measurement ◽  
Thermal Characterization ◽  
Phonon Transport ◽  
Thermal Conductivity Measurement ◽  
Great Success ◽  
Silicon Structures ◽  
Thin Silicon ◽  
20 Nm

Experimental measurement of thermal conductivity is considered the most reliable tool for the study of phonon transport in ultra-thin silicon structures. While there has been a great success in thermal conductivity measurement of ultra-thin silicon layers down to 20 nm over the past decade, it is not clear if the existing techniques and tools can be extended to the measurements of sun 100 Angstrom layers. In this paper, an analytical study of the feasibility of electrical Joule heating and thermometry in patterned metal bridges is presented. It is concluded that thermal conductivity of silicon layers as thin as 5 nm can be obtained (uncertainty 20%) by performing steady-state measurements using an on-substrate nanoheater structure. The thermal characterization of silicon layers as thin as 1 nm may be possible using frequency domain measurements.

scholarly journals Characterization of low thermal conductivity pan-based carbon fibers

Carbon ◽  
1994 ◽  
Vol 32 (3) ◽  
pp. 379-391 ◽  
Author(s):  
H.A. Katzman ◽  
P.M. Adams ◽  
T.D. Le ◽  
C.S. Hemminger
Keyword(s):  
Thermal Conductivity ◽  
Carbon Fibers ◽  
Low Thermal Conductivity

scholarly journals Thermal characterization of different graphite polystyrene

2018 ◽  
Vol 9 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Á. Lakatos ◽  
I. Deák ◽  
U. Berardi
Keyword(s):  
Thermal Conductivity ◽  
High Performance ◽  
Thermal Characterization ◽  
Expanded Polystyrene ◽  
High Moisture ◽  
Insulating Materials ◽  
Insulation Materials ◽  
Vacuum Insulation ◽  
Study Laboratory

The development of high performance insulating materials incorporating nanotechnologies has enabled considerable decrease in the effective thermal conductivity. Besides the use of conventional insulating materials, such as mineral fibers, the adoption of new nano-technological materials such as aerogel, vacuum insulation panels, graphite expanded polystyrene, is growing. In order to reduce the thermal conductivity of polystyrene insulation materials, during the manufacturing, nano/micro-sized graphite particles are added to the melt of the polystyrene grains. The mixing of graphite flakes into the polystyrene mould further reduces the lambda value, since graphite parts significantly reflect the radiant part of the thermal energy. In this study, laboratory tests carried out on graphite insulation materials are presented. Firstly, thermal conductivity results are described, and then sorption kinetic curves at high moisture content levels are shown. The moisture up-taking behaviour of the materials was investigated with a climatic chamber where the relative humidity was 90% at 293 K temperature. Finally, calorific values of the samples are presented after combusting in a bomb calorimeter.

X-Ray Characterization of Low-Thermal-Conductivity Thin-Film Materials

2009 ◽  
Vol 38 (7) ◽  
pp. 1402-1406 ◽  
Author(s):  
Paul Zschack ◽  
Colby Heideman ◽  
Clay Mortensen ◽  
Ngoc Nguyen ◽  
Mary Smeller ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Conductivity ◽  
X Ray ◽  
Low Thermal Conductivity

Cross-Verification of Thermal Characterization of a Microcooler

2007 ◽  
Vol 129 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Zs. Kohári ◽  
Gy. Bognár ◽  
Gy. Horváth ◽  
A. Poppe ◽  
M. Rencz ◽  
...  
Keyword(s):  
Heat Flux ◽  
Thermal Characterization ◽  
Structure Functions ◽  
Heat Flux Sensor ◽  
Thermal Measurements ◽  
The One ◽  
Radial Arrangement ◽  
The Heat Transfer Coefficient ◽  
Flux Sensor

The thermal behavior of a microcooler has been investigated using two different measurement methods to verify their feasibility. On the one hand structure function derived from the thermal measurements was used, while on the other hand, characterization was done with a heat-flux sensor array. The measurement sample was a square nickel plate microcooler holding 128 microchannels in radial arrangement. In our previous studies it was attached to a power transistor which was used as a dissipator and a temperature sensor. The thermal transient response to a dissipation step of the transistor was recorded in the measurement. The measured transients (cooling curves) were transformed into structure functions from which the partial thermal resistance corresponding to the cooling assembly was identified. In the current study the measurement setup was completed by a heat-flux sensor inbetween the dissipator and the microcooler to be able to verify the results extracted via structure functions. In this way we could compare the heat-transfer coefficient (HTC) values obtained from the identified thermal resistances to those calculated directly from the measured heat-flux values. Good matching of the HTC values resulting from the two different methods was found.

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