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Available data on insulating, semiconducting, and metallic solids verify our new model that incorporates steady-state heat flow into a macroscopic, thermodynamic description of solids, with agreement being best for isotropic examples. Our model is based on: (1) mass and energy conservation; (2) Fourier’s law; (3) Stefan–Boltzmann’s law; and (4) rigidity, which is a large, yet heretofore neglected, energy reservoir with no counterpart in gases. To account for rigidity while neglecting dissipation, we consider the ideal, limiting case of a perfectly frictionless elastic solid (PFES) which does not generate heat from stress. Its equation-of-state is independent of the energetics, as in the historic model. We show that pressure-volume work (P𝜕V) in a PFES arises from internal interatomic forces, which are linked to Young’s modulus (Ξ) and a constant (n) accounting for cation coordination. Steady-state conditions are adiabatic since heat content (Q) is constant. Because average temperature is also constant and the thermal gradient is fixed in space, conditions are simultaneously isothermal: Under these dual restrictions, thermal transport properties do not enter into our analysis. We find that adiabatic and isothermal bulk moduli (B) are equal. Moreover, Q/V depends on temperature only. Distinguishing deformation from volume changes elucidates how solids thermally expand. These findings lead to simple descriptions of the two specific heats in solids: 𝜕ln(cP)/𝜕P = −1/B; cP = nΞ times thermal expansivity divided by density; cP = cVnΞ/B. Implications of our validated formulae are briefly covered.

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“…Grey long dashes = laser flash calorimetry [ 110 ]. Grey short dashes = pulse calorimetry [ 111 ]. Dark grey line = pulse calorimetry [ 112 ].…”

Section: Figure A1mentioning

confidence: 99%

Thermodynamic Relationships for Perfectly Elastic Solids Undergoing Steady-State Heat Flow

Hofmeister

Criss

2022

Materials

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“…). e is the spectral emissivity which depends on the condition of the materials surface, for un-polished tantalum it was measured to be around 0.32 over the temperature range 1100 -2300 K 39 . T (r) is the radial temperature profile and is given by,…”

Section: Beam Heating Of the Convertermentioning

confidence: 99%

Simulations of slow positron production using a low-energy electron accelerator

O’Rourke

Hayashizaki

Kinomura

et al. 2011

Review of Scientific Instruments

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Monte Carlo simulations of slow positron production via energetic electron interaction with a solid target have been performed. The aim of the simulations was to determine the expected slow positron beam intensity from a low energy, high current electron accelerator. By simulating (a) the fast positron production from a tantalum electron-positron converter and (b) the positron depth deposition profile in a tungsten moderator, the slow positron production probability per incident electron was estimated. Normalizing the calculated result to the measured slow positron yield at the present AIST LINAC the expected slow positron yield as a function of energy was determined. For an electron beam energy of 5 MeV (10 MeV) and current 240 µA (30 µA) production of a slow positron beam of intensity 5 × 10 6 s −1 is predicted. The simulation also calculates the average energy deposited in the converter per electron, allowing an estimate of the beam heating at a given electron energy and current. For low energy, high-current operation the maximum obtainable positron beam intensity will be limited by this beam heating.

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“…The original method proposed for the thermal-diffusivity measurement of such liquids (called special in this paper) is a modified THW method using a two-wire probe, according to a measurement principle previously developed in [9] for the thermal-diffusivity determination of soils; moreover, for applications to such special liquids, the tantalum technology has been chosen because tantalum metal has well known electrical and thermal properties [10,11] and a very high resistance to corrosion with most concentrated strong acids (nitric, sulfuric, hydrochloric, and hydrobromic,. .…”

Section: Introductionmentioning

confidence: 99%

A New Transient Two-Wire Method for Measuring the Thermal Diffusivity of Electrically Conducting and Highly Corrosive Liquids Using Small Samples

et al. 2008

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International audienceThe transient hot-wire (THW) technique is widely used for measurements of the thermal conductivity of most fluids, and some attempts have also been carried out for simultaneous measurements of the thermal diffusivity with the same hot wire. However, for some particular liquids like concentrated nitric acid solutions or similar nitric mixtures, for which the thermal properties are important for industrial or security applications, this technique may be difficult to use, because of possible technological incompatibilities between measurement probe materials and highly electrically conducting and corrosive liquids. Moreover, the possible highly energetic (explosive) character of these liquids requires minimum volume liquid samples and safety measurement devices and processes. It is the purpose of this paper to report on a modified THW technique (previously used for thermal-diffusivity measurements in soils), which is associated with a specific patented double-wire probe and is shown to be valid for direct thermal-diffusivity measurements in liquids. This method responds to the previous requirements and allows automatic and quasi-simultaneous thermal-conductivity and thermal-diffusivity measurements to be made safely on liquids compatible with the tantalum technology, with liquid sample volumes < 2 cm3. Low uncertainties are found for the thermal-diffusivity data when relative measurements are carried out with reference liquids like water or toluen

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Cited by 50 publications

References 6 publications

Thermodynamic Relationships for Perfectly Elastic Solids Undergoing Steady-State Heat Flow

Thermodynamic Relationships for Perfectly Elastic Solids Undergoing Steady-State Heat Flow

Simulations of slow positron production using a low-energy electron accelerator

A New Transient Two-Wire Method for Measuring the Thermal Diffusivity of Electrically Conducting and Highly Corrosive Liquids Using Small Samples

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