A Phase-Sensitive Technique for the Thermal Characterization of Dielectric Thin Films

1999 ◽  
Vol 121 (3) ◽  
pp. 528-536 ◽  
Author(s):  
S. W. Indermuehle ◽  
R. B. Peterson
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Specific Heat ◽  
Temperature Response ◽  
Front Surface ◽  
Thermal Characterization ◽  
Fused Silica ◽  
Dielectric Thin Films ◽  
Phase Sensitive

A phase-sensitive measurement technique for determining two independent thermal properties of a thin dielectric film is presented. The technique involves measuring a specimen’s front surface temperature response to a periodic heating signal over a range of frequencies. The phase shift of the temperature response is fit to an analytical model using thermal diffusivity and effusivity as fitting parameters, from which the thermal conductivity and specific heat can be calculated. The method has been applied to 1.72-μm thick films of SiO2 thermally grown on a silicon substrate. Thermal properties were obtained through a temperature range from 25°C to 300°C. One interesting outcome stemming from analysis of the experimental data is the ability to extract both thermal conductivity and specific heat of a thin film from phase information alone. The properties obtained with this method are slightly below the bulk values for fused silica with a measured room temperature (25°C) thermal conductivity of 1.28 ± 0.12 W/m-K.

A Phase-Sensitive Technique for Measurements of Liquid Thermal Conductivity

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Zhefu Wang ◽  
Richard B. Peterson
Keyword(s):  
Thermal Conductivity ◽  
Stainless Steel ◽  
Thermal Properties ◽  
Steel Strip ◽  
Infrared Detector ◽  
Temperature Response ◽  
Front Surface ◽  
Test Liquid ◽  
Conduction Model ◽  
Conductivity Enhancement

An experimental technique based on the thermal wave approach for measuring the thermal conductivity of liquids is developed in this paper. A stainless steel strip functions as both a heating element and a sealing cover for a chamber containing a test liquid. A periodic current passing through this metal strip generates a periodic Joule heating source. An infrared detector measures the temperature response at the front surface of the stainless steel strip. The phase and magnitude of the temperature response with respect to the heating signal were measured by a lock-in amplifier at various frequencies from 22 Hz to 502 Hz. A one-dimensional, two-layered transient heat conduction model was developed to predict the temperature response on the front surface of the stainless steel strip. The phase information from this temperature response shows high sensitivity to the change in thermal properties of the liquid layer and is employed to match experimental data to find the thermal properties of the test liquid. The measured thermal conductivities of water and ethylene glycol agree quite well with the data from literature and support the validity of this measurement technique. An aqueous fluid consisting of gold nanoparticles is tested and anomalous thermal conductivity enhancement is observed. A discrepancy in the thermal transport behavior between pure liquids and nanofluids is suggested from our experimental results.

Laser Flash Measurement of Samples With a Transparent Reference Layer

2009 ◽  
Author(s):  
Heng Ban ◽  
Zilong Hua
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Temperature Response ◽  
Front Surface ◽  
Laser Flash ◽  
Laser Flash Method ◽  
Flash Method ◽  
Thermal Diffusivity Measurement ◽  
Reference Layer

The laser flash method is a standard method for thermal diffusivity measurement. This paper reports the development of a method and theory that extends the standard laser flash method to measure thermal conductivity and thermal diffusivity simultaneously. By attaching a transparent reference layer with known thermal properties on the back of a sample, the thermal conductivity and thermal diffusivity of the sample can be extracted from the temperature response of the interface between the sample and the reference layer to a heating pulse on the front surface. The theory can be applied for sample and reference layer with different thermal properties and thickness, and the original analysis of the laser flash method becomes a limiting case of the current theory with an infinitely small thickness of the reference layer. The uncertainty analysis was performed and results indicated that the laser flash method can be used to extract the thermal conductivity and diffusivity of the sample. The results can be applied to, for instance, opaque liquid in a quartz dish with silicon infrared detector measuring the temperature of liquid-quartz interface through the quartz.

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.

3D Examination of the Thermal Properties of Carbon-Carbon Composites

2014 ◽  
Author(s):  
Melanie Patrick ◽  
Messiha Saad
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
High Temperature ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermal Characterization ◽  
Flash Method ◽  
Carbon Composites ◽  
Scanning Calorimetry ◽  
Temperature Levels

Thermal characterization of composites is essential for their proper assignment to a specific application. Specific heat, thermal diffusivity, and thermal conductivity of carbon-carbon composites are essential in the engineering design process and in the analysis of aerospace vehicles, space systems and other high temperature thermal systems. Specifically, thermal conductivity determines the working temperature levels of a material and is influential in its performance in high temperature applications. There is insufficient thermal property data for carbon-carbon composites over a range of temperatures. The purpose of this research is to develop a thermal properties database for carbon-carbon composites that will contain in-plane (i-p) and through-the-thickness (t-t-t) thermal data at different temperatures as well as display the effects of graphitization on the composite material. The carbon-carbon composites tested were fabricated by the Resin Transfer Molding (RTM) technique, utilizing T300 2-D carbon fabric and Primaset PT-30 cyanate ester resin. Experimental methods were employed to measure the thermal properties. Following the ASTM standard E-1461, the flash method enabled the direct measurement of thermal diffusivity. Additionally, differential scanning calorimetry was performed in accordance with the ASTM E-1269 standard to measure the specific heat. The measured thermal diffusivity, specific heat, and density data were used to compute the thermal conductivity of the carbon-carbon composites. The measured through-the-thickness thermal conductivity values of all the materials tested range from 1.0 to 17 W/m·K, while in-plane values range from 3.8 to 4.6 W/m·K due to the effect of fiber orientation. Additionally, the graphitized samples exhibit a higher thermal conductivity because of the nature of the ordered graphite structure.

scholarly journals Production and Thermal Characterization of Ethanol Blends from Black Jaggery

2020 ◽  
Vol 8 (6) ◽  
pp. 5398-5401
Keyword(s):  
Thermal Conductivity ◽  
Global Warming ◽  
Thermal Properties ◽  
Fossil Fuels ◽  
Fossil Fuel ◽  
Thermal Characterization ◽  
Thermal Constant ◽  
Ethanol Blends ◽  
Alternate Fuels

To protect the environment from the global warming dependency on the fossil fuels have to be reduced. Locally available alternate fuels are greatly prominent for the development of industrialization compared to conventional fuels. This paper mainly deals with the production of Ethanol from a source called “Black Jaggery” and an Optimization of the extracted alcohol to attain the characteristics and properties which would be essential to blend the alcohol with an existing fossil fuel. Black Jaggery being a sugar-based product is fermented in the presence of a yeast enzyme for several days and is distilled to extract the bio-fuel (ethanol) from the source. The extracted oil is characterized for the thermal properties by using thermal constant analyzer TPS-500 which will be helpful for the combustion studies. Obtained results shows that compared to E-5, E-10 and E-20, E-15 blend shows better thermal properties increased thermal conductivity, thermal diffusivity with reduced specific heat.

Thermal Wave Based Measurement of Liquid Thermal Conductivities

2008 ◽  
Author(s):  
Zhefu Wang ◽  
Richard B. Peterson
Keyword(s):  
Thermal Conductivity ◽  
Stainless Steel ◽  
Thermal Properties ◽  
Steel Strip ◽  
Measurement Techniques ◽  
Temperature Response ◽  
Front Surface ◽  
Conduction Model ◽  
Closed Chamber ◽  
Thermal Conductivities

This work develops an experimental technique capable of determining thermal conductivity of liquids with application to nanofluids. A periodic current passing through a thin stainless steel strip generates a periodic Joule heating source and an infrared detector measures the temperature response at the front surface of the stainless steel strip. An open chamber is machined out of a delrin plate with the stainless steel strip acting as the sealing cover. This resulting closed chamber contains the test liquid. The phase and magnitude of the temperature response were measured using a lock-in amplifier at various frequencies from 22 to 502 Hz. A one-dimensional, two-layered transient heat conduction model was developed to predict the temperature response on the front surface of the stainless steel strip. This temperature response, including phase and magnitude, is a function of the thermal properties of the liquid. The phase information shows high sensitivity to thermal properties of the liquid layer and is employed to match experimental data to find thermal conductivities. The measured thermal conductivities of water and ethylene glycol agree well with data from the literature and support the validity of this measurement technique. An aqueous fluid consisting of gold nanoparticles was tested. Anomalous thermal conductivity enhancement was observed. Our measurement results also show a divergence of thermal transport behavior between nanofluids and pure liquids. This suggests the need to carefully examine the role of measurement techniques in the study of nanofluid heat transfer phenomena.

Thermal Characterization of a Reinforced Elastomer

2014 ◽  
Vol 529 ◽  
pp. 97-101
Author(s):  
Fabrizia Ghezzo ◽  
Xi Geng Miao ◽  
Ruo Peng Liu
Keyword(s):  
Heat Capacity ◽  
Thermal Properties ◽  
Specific Heat ◽  
High Performance ◽  
Glass Fibers ◽  
Thermal Characterization ◽  
Alumina Nanoparticles ◽  
Experimental Characterization ◽  
Short Glass

The effect of the presence of fillers on the thermal properties of a high performance elastomer was investigated in this work. The characterization of the specific heat capacity (Cp), the specific heat flow and the glass transition temperature of a polyurea elastomer reinforced with two different classes of fillers, i.e. short glass fibers and alumina nanoparticles, was conducted by using a differential scanning calorimeter (DSC). We present and discuss the results of the experimental characterization carried out on the reinforced material. The results are compared to those obtained by testing the pure polymer.

Mechanical and thermal characterization of grafted PP-NCC nanocomposites

2019 ◽  
pp. 089270571987822
Author(s):  
Saud Aldajah ◽  
Mohammad Y Al-Haik ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik
Keyword(s):  
Thermal Properties ◽  
Interfacial Adhesion ◽  
Thermal Characterization ◽  
Mechanical And Thermal Properties ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Three Point Bending ◽  
Twin Screw ◽  
Thermal Stability Of

This study reveals the enhancement of mechanical and thermal properties of maleic anhydride-grafted polypropylene (PP- g-MA) with the addition of nanocrystalline cellulose (NCC). A nanocomposite was manufactured by blending various percentages of PP, MA, and NCC nanoparticles by means of a twin-screw extruder. The influence of varying the percentages of NCC on the mechanical and thermal behavior of the nanocomposite was studied by performing three-point bending, nanoindentation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy tests. The novelty of this study stems on the NCC nanoparticles and their ability to enhance the mechanical and thermal properties of PP. Three-point bending and nanoindentation tests revealed improvement in the mechanical properties in terms of strength, modulus, and hardness of the PP- g-MA nanocomposites as the addition of NCC increased. SEM showed homogeneity between the mixtures which proved the presence of interfacial adhesion between the PP- g-MA incorporated with NCC nanoparticles that was confirmed by the FTIR results. DSC and TGA measurements showed that the thermal stability of the nanocomposites was not compromised due to the addition of the coupling agent and reinforced nanoparticles.

Thermal Characterization of Carbon-Carbon Composites

2011 ◽  
Author(s):  
Messiha Saad ◽  
Darryl Baker ◽  
Rhys Reaves
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Critical Role ◽  
Carbon Composite ◽  
Flash Method ◽  
Carbon Composites ◽  
Energy Storage Devices ◽  
Graphitized Carbon

Thermal properties of materials such as specific heat, thermal diffusivity, and thermal conductivity are very important in the engineering design process and analysis of aerospace vehicles as well as space systems. These properties are also important in power generation, transportation, and energy storage devices including fuel cells and solar cells. Thermal conductivity plays a critical role in the performance of materials in high temperature applications. Thermal conductivity is the property that determines the working temperature levels of the material, and it is an important parameter in problems involving heat transfer and thermal structures. The objective of this research is to develop thermal properties data base for carbon-carbon and graphitized carbon-carbon composite materials. The carbon-carbon composites tested were produced by the Resin Transfer Molding (RTM) process using T300 2-D carbon fabric and Primaset PT-30 cyanate ester. The graphitized carbon-carbon composite was heat treated to 2500°C. The flash method was used to measure the thermal diffusivity of the materials; this method is based on America Society for Testing and Materials, ASTM E1461 standard. In addition, the differential scanning calorimeter was used in accordance with the ASTM E1269 standard to determine the specific heat. The thermal conductivity was determined using the measured values of their thermal diffusivity, specific heat, and the density of the materials.

Effect of polycyclosilane microstructure on thermal properties

2021 ◽  
Author(s):  
Qifeng Jiang ◽  
Sydnee Wong ◽  
Rebekka S Klausen
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Thermal Characterization ◽  
Side Chains ◽  
Phase Properties

Thermal characterization of polysilanes has focused on the influence of organic side chains, whereas little is understood about the influence of silane backbone microstructure on thermal stability, phase properties, and...

Sign in / Sign up

Export Citation Format

Share Document