International Journal of Thermophysics

http://link.springer.com/journal/10765

List of Papers (Total 122)

Measuring Sound Speed in Gas Mixtures Using a Photoacoustic Generator

We present a new method which allows us to percentage distinction of gas composition with a fast response time. This system uses the speed of sound in a resonant cell along with temperature to determine the gas mixture composition. The gas mixtures contain two gases with an unknown combination. In our experiment, the acoustic waves were excited inside the acoustic longitudinal ...

Thermographic Assessment of the HAZ Properties and Structure of Thermomechanically Treated Steel

Thermomechanically processed steels are materials of great mechanical properties connected with more than good weldability. This mixture makes them interesting for different types of industrial applications. When creating welded joints, a specified amount of heat is introduced into the welding area and a so called heat-affected zone (HAZ) is formed. The key issue is to reduce the ...

Measurement of Out-of-Plane Thermal Conductivity of Epitaxial \(\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-{\delta }}\) Thin Films in the Temperature Range from 10 K to 300 K by Photothermal Reflectance

We measured the out-of-plane (c-axis) thermal conductivity of epitaxially grown \(\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-{\delta }}\) (YBCO) thin films (250 nm, 500 nm and 1000 nm) in the temperature range from 10 K to 300 K using the photothermal reflectance technique. The technique enables us to determine the thermal conductivity perpendicular to a thin film on a substrate by ...

Thermodynamic Temperature of High-Temperature Fixed Points Traceable to Blackbody Radiation and Synchrotron Radiation

Absolute spectral radiometry is currently the only established primary thermometric method for the temperature range above 1300 K. Up to now, the ongoing improvements of high-temperature fixed points and their formal implementation into an improved temperature scale with the mise en pratique for the definition of the kelvin, rely solely on single-wavelength absolute radiometry ...

SLS: One of the Modern Technologies of Laser Surface Treatment

Photovoltaic cells are one way of achieving solar energy. One of the stages of their fabrication is the production of front electrode. The application of an unconventional method of selective laser sintering using the \(\hbox {CO}_{2 }\) laser for the fabrication of front electrode of silicon photovoltaic cell was a real challenge. The most notable research results yielded by the ...

Impact of Frequency of Load Changes in Fatigue Tests on the Temperature of the Modified Polymer

In the article, the authors describe the analysis of the impact of the frequency of fatigue tests on the temperature of the modified polymer. The base material for producing the samples was the epoxy resin Epidian 57 cured with Z1 hardener. The presented study is part of a research program of adhesive joints made with the composition Epidian 57/Z1 aiming to determine the effect of ...

\(\hbox {Au}^{2+}\) -Implanted Regions in Silicon Visualized Using a Modulated Free-Carrier Absorption Method

Silicon samples were implanted with \(\hbox {Au}^{2+}\) ions of energy 100 keV and doses of \(10^{14}\,\hbox { cm}^{-2}\). The area of the implanted region was \(2\,\hbox {mm}\times 2\,\hbox {mm}\). The size of the Si substrate samples was \(5\,\hbox {mm}\times 5\,\hbox {mm}\times 0.4\,\hbox {mm}\). Spatial distributions of the amplitude and profiles of the modulated free-carrier ...

A Thermodynamic Consideration on the Mechanism of Ultrasensitive Moisture Sensing by Amorphous Silica

We detected the change in the phase velocity of surface acoustic waves propagating along the amorphous silica layer on a spherical single-crystal quartz due to the very small amount of moisture at less than \(1~\upmu \hbox {mol}{\cdot } \hbox {mol}^{-1}\) in the ambient \(\hbox {N}_{2}\) gas. This was made possible for the first time because this system, called a ball SAW moisture ...

Tests of the Stability of Chinese RhFe Resistance Thermometers at Low Temperatures

Rhodium–iron resistance thermometers are recommended as precise thermometers at temperatures below 25 K. The thermometers were developed at the National Physical Laboratory and produced by H. Tinsley and Co Ltd almost 50 years ago. Later, they were made by other companies and institutes as well, but despite this, the availability of the thermometers decreased and a new source of ...

Numerical Modeling of Photothermal Experiments on Layered Samples with Mirage-Effect Signal Detection

Modeling of the probe beam deflection caused by temperature gradients for layered sample was realized in COMSOL Multiphysics, which utilizes finite element method to analyze heat transport. The sample consisted of a 100-nm-thick layer on a 500-\(\upmu \)m-thick substrate. It was also assumed that the sample was illuminated with either a Gaussian or a flat top beam of harmonically ...

Comparison of the Argon Triple-Point Temperature in Small Cells of Different Construction

The argon triple point (\(T_{90} = 83.8058\,\hbox {K}\)) is a fixed point of the International Temperature Scale of Preston-Thomas (Metrologia 27:3, 1990). Cells for realization of the fixed point have been manufactured by several European metrology institutes (Pavese in Metrologia 14:93, 1978; Pavese et al. in Temperature, part 1, American Institute of Physics, College Park, 2003; ...

High-Accuracy Emissivity Data on the Coatings Nextel 811-21, Herberts 1534, Aeroglaze Z306 and Acktar Fractal Black

The Physikalisch-Technische Bundesanstalt determined the directional spectral emissivities of several widely used black coatings: Nextel 811-21, Herberts 1534, Aeroglaze Z306 and Acktar Fractal Black. These are and were often applied in different industrial and scientific applications. The measurements are taken angularly resolved over a range from \(10{^{\circ }}\) to \(70{^{\circ ...

Thermophysical Properties of Five Industrial Steels in the Solid and Liquid Phase

The need for characterization of thermophysical properties of steel was addressed in the FFG-Bridge Project 810999 in cooperation with our partner from industry, Böhler Edelstahl GmbH & Co KG. To optimize numerical simulations of production processes such as plastic deformation or remelting, additional and more accurate thermophysical property data were necessary for the group of ...

Study of Polyurethane Foaming Dynamics Using a Heat Flow Meter

This work presents the results of the study concerning the effects of fillers addition on the heat flux density \(\dot{q}\left( t \right) \) of foaming of polyurethane–polystyrene porous composite (PSUR) and describes the dynamics of this process during the first 600 s. This foaming process resulted in obtaining porous materials that were based on HFC 365/225 blown rigid ...

The Tracking Resonance Frequency Method for Photoacoustic Measurements Based on the Phase Response

One of the major issues in the use of the resonant photoacoustic cell is the resonance frequency of the cell. The frequency is not stable, and its changes depend mostly on temperature and gas mixture. This paper presents a new method for tracking resonance frequency, where both the amplitude and phase are calculated from the input samples. The stimulating frequency can be adjusted ...

Cooling of High-Power LED Lamp Using a Commercial Paraffin Wax

Commercial paraffin wax used by Bolsius Nederland B.V. for manufacturing various kinds of candles was applied as a phase-change material (PCM) for cooling a 28 W high-power light emitting diode (LED) panel during its operation. The main problem arising during operation of an LED is thermal management. According to the manufacturer’s datasheet specifications (BioSolution Ltd. ...

Density Functional Study of the Carbon Dependence of the Structural, Mechanic, Thermodynamic, and Dynamic Properties of SiC Alloys

Using a density functional scheme, for the first time the carbon dependence on the structural, dynamic, thermodynamic, and dynamic properties of \(\hbox {Si}_{1-x}\hbox {C}_{x} \) alloys (\(x=0.0\) to 1.0 in steps of 0.125) has been investigated. The structural properties of these materials, in particular, the composition dependence of the lattice parameter and bulk modulus, are in ...

Comparison of Theoretical Basics of Microphone and Piezoelectric Photothermal Spectroscopy of Semiconductors

Photothermal spectroscopy has found a wide range of applications as a method of monitoring thermal, optical and recombination parameters of semiconductors. We consider microphone detection, widely used in photoacoustic spectroscopy, and piezoelectric detection. Both methods require knowledge of the temperature distribution in the sample and in its surroundings, the support surface ...

Quantitative Thermal Microscopy Measurement with Thermal Probe Driven by dc+ac Current

Quantitative thermal measurements with spatial resolution allowing the examination of objects of submicron dimensions are still a challenging task. The quantity of methods providing spatial resolution better than 100 nm is very limited. One of them is scanning thermal microscopy (SThM). This method is a variant of atomic force microscopy which uses a probe equipped with a ...

Optodynamic Phenomena During Laser-Activated Irrigation Within Root Canals

Laser-activated irrigation is a powerful endodontic treatment for smear layer, bacteria, and debris removal from the root canal. In this study, we use shadow photography and the laser-beam-transmission probe to examine the dynamics of laser-induced vapor bubbles inside a root canal model and compare ultrasonic needle irrigation to the laser method. Results confirm important ...

The Russian National Standard of Gases Humidity and Traceability System of Humidity Measurements

The Russian national humidity standard of gases has been modernized in order to increase the number of reproducible quantities of humidity (relative humidity, dew/frost-point temperature, mole fraction) and to extend the humidity and operating temperature ranges. The basis of the standard comprises two humidity generators with operating temperature ranges from \(5\,^{\circ }\hbox ...