Heat transfer coefficient (HTC) is a useful concept to characterize the heat exchange performance of rock fracture. However, existing study has preliminarily found that some HTC formulas would lead to abnormal values, which claims a systematical evaluation of existing formulas. In this paper, 214 test records are employed to evaluate 8 existing formulas from literature. It is found that, for all these

New experimental data for the thermal conductivity of cis-1,1,1,4,4,4-hexafluoro-2-butene (R-1336mzz(Z)) are reported for vapor, liquid, and supercritical states. These data were obtained with transient hot-wire apparatus over the temperature range from 192 K to 498 K and at pressures from 0.05 MPa to 69 MPa. These data were used to develop a wide-range correlation for the thermal conductivity of the

The present contribution examines the accessibility of diffusivities across the two-phase region of an equimolar methane–propane mixture for dynamic light scattering (DLS) experiments. Heterodyne DLS experiments and theoretical calculations of the Rayleigh ratio were performed at 125 different thermodynamic states including the gas, liquid, supercritical, and the two-phase region. The present measurements

A series of metal–carbon (M–C) eutectics with robust reproducible melting phase transitions are evolving as the reference high-temperature fixed-points up to 3000 °C for radiation thermometry. The mise-en-pratique prepared for the realization and dissemination of new kelvin allows the use of set of M-C blackbody fixed-points or a combination of M-C fixed-points along with silver (Ag), gold (Au) or

Present work reports thermal conductivity measurement in a commercial soda–lime–silica glass substrate by the transient 3\(\omega\) method using a unique, custom-built in-house setup. Most importantly, a micro-heater (MH) cum temperature sensor is fabricated for this purpose. At first the MH-patterned mask is developed by CO2 laser cutting technique on quartz glass. The MH (L-5 mm, W-65–70 μm, t-140 nm)

Photoacoustic spectroscopy (PAS) has been widely used as a nondestructive and sensitive analytical technique used to determine the thermal diffusivity, effusivity and heat capacity of different materials. In this work, the open cell photoacoustic technique (OPC) technique was used for the kinematic study of heat transfer processes as a function of time for curing nanoresin composites. An exponential

Although in the case of fluids there are several reference correlations of low uncertainty for thermal conductivity, for solids there are very few and in a restricted temperature range. The available experimental data for the thermal conductivity of five widely used solids, BK7, PMMA, Pyrex 7740, Pyroceram 9606, and SS304, have been critically examined with the intention of establishing thermal conductivity

The extraction of silver by dodecylamine under neutral condition was studied. The extraction rates of silver at different temperatures and ionic strengths were calculated, and the optimum extraction factors were analyzed. The extraction rate decreases with increasing temperature, and the extraction rate can up to 98.79%. The physicochemical characters of the reaction such as the standard equilibrium

In the present paper, the governing equations for two-temperature generalized porothermoelasticity are formulated in accordance with Green and Naghdi theory of thermoelasticity without energy dissipation. Two-dimensional plane wave solution of these governing equations indicates the existence of one shear vertical and four coupled longitudinal waves in porothermoelastic medium. A problem on reflection

The purpose of this investigation is providing a method to study the effect of porosity in a porothermoelastic medium by the finite element technique. The formulations are applied under Green-Naghdi model without energy dissipations. One-dimensional application for a poroelastic half-space is considered. Due to the complex basic equations, the finite element method (FEM) has been adopted to solve this

This article presents a simple thermal characterization method, noted CFM, for the measurement of the apparent thermal conductivity of insulating materials at high temperature (i.e., up to 600 °C). The CFM method is a steady-state relative measurement method which requires a calibration. The calibration of the experimental apparatus was done with a calcium silicate board of known thermal conductivity

The search for excellent heat transfer fluids necessitates the development of novel nanofluids. The paper is the first report revealing the potential of sodium carbide (Na2C2) nanoparticle for heat transfer and thermal shielding applications. For this, Na2C2 is prepared from the porous carbon matrix of Aloe vera leaves by hydrothermal method. The morphological changes on hydrothermal treatment and

PVT properties and the thermal-pressure coefficient, \(\gamma_{\text{V}} = \left( {\partial P/\partial T} \right)_{\text{V}}\), of 2-propanol have been simultaneously measured in the near- and supercritical regions using high-temperature and high-pressure nearly constant-volume piezo-calorimeter. Measurements were made along 9 liquid and 3 vapor isochores between (234.3 and 697.69) kg·m−3 and at temperatures

α-Fe2O3 and ε-Fe2O3 thin-film hematite polymorphs, as well as Fe2O3 polymorphs’ thin films coated with TiO2 nanolayer, all deposited on Si substrate plates, were investigated by an open photoacoustic cell set-up within the 20 Hz–20 kHz modulation frequency range. Theoretical analysis of experimental results was based on a two-layer model which includes both substrate and thin-film parameters. For different

We solved the Dirac equation using modified factorization method with hyperbolic Pöschl–Teller potential model. Relativistic and non-relativistic ro-vibrational energy spectra were obtained and numerical solutions for four diatomic molecules \(\left( {{\text{HCl}},\;{\text{H}}_{2} ,\;{\text{CO}}\;{\text{and}}\;{\text{LiH}}} \right)\) obtained also. The eigenfunction for this potential has been obtained

In the context of a numerical study about mid-infrared receivers based on a metal–insulator–metal junction, we study how a top multilayer of graphene is capable to remove heat from the thin metal layer in which the laser impinges on. Due to its extremely high thermal conductivity, the graphene film (made of several layers) extracts the heat and injects it inside bulky lateral metal paddings of the

A difference was determined between temperature defined by International Temperature Scale (ITS-90) and thermodynamic temperature measured by relative acoustic gas thermometry at 79.0000 K and at 83.8058 K. Measurement were carried out using misaligned spherical acoustic resonator filled with helium at different pressures. The isotherms were fitted for four different acoustic modes simultaneously assuming

The annual output of crops in China is about 900 million tons. Improper handling of large amounts of straw waste increases the negative impact on the environment. Recently, many scholars have studied the rational use of crop straw, and found that straw was rich in plant fiber, which combined with some kinds of building materials could be used to produce new green composite building materials. The composite

In the present work, the method which allows investigating the spatial distribution of light extinction coefficient in colloidal media is experimentally realized. The proposed method is based on the dependence of temporal profiles of excited OA-signals on the absorption and extinction coefficients of the studied medium. Water-based and kerosene-based magnetic fluids with volume content of magnetite

Molten salts are being used as heat transfer fluids and thermal energy storage materials for concentrated solar power (CSP) plants. It is imperative to choose the right Heat Transfer Fluids (HTF) and equally important to have accurate data on the properties of the same to help in the design of a new HTF. Determining the thermophysical properties of these HTFs accurately is a challenging task as it

We present an explicit, simple and yet accurate expression of the heat capacity of solids by approximating the Debye integral. This model can be used for temperatures greater than one-tenth of Debye temperature. The results of this approximate model are finally compared with experimental data of Cu, MgO and ZnO and show a very good agreement.

A refrigerant mixture of R1123 + R32 is expected to be an alternative working fluid for refrigeration systems, organic Rankine cycle and heat pumps due to its lower global warming potential and transport properties. The goals of this work are to measure the viscosity of the liquid and vapor phases of this mixture refrigerant. Consequently, the viscosity of mixture refrigerant was measured by the tandem

In this article, we propose a numerical analysis of the effect of the orthotropic tensor of thermal conductivity during microwave heating of a heterogeneous core–shell morphology. The core is made of a material with high thermal conductivity, whose dielectric loss coefficient guarantees high microwave energy to heat conversion. This type of morphology has a high potential for use in the ablation of

In order to improve the detection sensitivity and stability of scanning laser ultrasound techniques, we propose a transmission time delay method, based on the time delay of transmitted longitudinal waves, for the evaluation of the size and position of an internal cavity. By studying the interacting process between the longitudinal wave and the internal cavity through theory and finite element method

In order to study the charge characteristics of monocrystalline silicon irradiated by femtosecond pulsed laser, measurement systems of charge and infrared temperature induced by femtosecond pulse laser irradiation monocrystalline silicon are established by using oscilloscope and infrared thermal imager. The monocrystalline silicon (circle disc) irradiated by femtosecond pulse laser are carried out

Transport properties of nano-confined fluids such as diffusivity can exhibit utterly distinctive characteristics compared to the transport properties in the bulk due to the interactions between atoms in the solid walls and fluid atoms as well as the confinements. In this paper, the diffusivity of water confined in the graphene nanochannels is calculated by molecular dynamics simulations through the

Since the mathematical foundations of photothermal effects in condensed phase materials were established in the middle 1970s, new photothermal methodologies have emerged based on the detection of heat generated from the absorption and non-radiative conversion of modulated radiation. Among them, photopyroelectric techniques have become very popular and widely used for a variety of studies ranging from

The sky thermal irradiance (Rsky) is an important factor in meteorological, climatic, and energy balance studies. There are several empirical models for predicting Rsky; however, these are based on the meteorological parameters measured in non-arid climatic conditions and an empirical model for predicting Rsky in arid climates is unavailable. Therefore, this study presents two empirical models for

Recently, it has been found that surface tension of a colloid solution maintained lower value by microwave irradiation even after the microwave was turned off. The results verified bubbles around particles due to microwave. In this study, the surface tension and particle-bubble were monitored during and after the irradiation for suspension from an aqueous solution of ferric chloride. The surface tension

The original version of the article unfortunately contained some errors in Table 3. The viscosity data of diethyl adipate from 353.15 K and 40 MPa, to 363.15 K and 40 MPa were modified. Corrected version of Table 3 is given below.

In this paper, a methodology for the application of neural networks in phase-match calibration of gas–microphone photoacoustics in frequency domain is developed. A two-layer deep neural network is used to determine, in real-time, reliably and accurately, the phase transfer function of the used microphone, applying the photoacoustic response of aluminum as reference material. This transfer function

This experimental study deals with the critical heat flux (CHF) of aqua-based reduced graphene oxide (rGO) nanofluids at 0.2 %, 0.6 %, and 0.8 % concentrations. This investigation also interprets the results of different characterization studies of rGO nanofluid namely atomic force microscopy (AFM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), dynamic light scattering

The reduction of device components is of a major interest for the conception of low-cost devices with a simple design. Generally, the boxes method measures the effective thermal conductivity of relatively large-sized samples due to its industrial purposes. However, to determine the thermal conductivity of small samples, additional sensors are required. In this work, a new experimental procedure is

We respond to recent articles (Int. J. Thermophysics 39 139 2018, ibid.40 21 2019) that seek to deny the veracity of the empirical discovery and thermodynamic description of a gas–liquid supercritical mesophase. These IJT articles are misleading because they are based upon a false premise that the mesophase is a hypothetical concept. There is no “mesophase hypothesis” as wrongly stated in the title

We present additional data on the dielectric constant (relative permittivity) and liquid density of mixtures of carbon dioxide (CO2) and squalane (2,6,10,15,19,23-hexamethyltetracosane) for temperatures between 283 K and 343 K. The data were obtained in the apparatus of Ref. [1] using the same experimental procedure. The first-order Redlich–Kister volume fraction expansion proposed in Ref. [1] to calculate

A new method is developed for correlating the static dielectric constant of polar fluids over wide ranges of conditions where few experimental data exist. Molecular dynamics simulations are used to establish the temperature and density dependence of the Kirkwood g-factor, and also the functional form for the increase of the effective dipole moment with density. Most parameters in the model are obtained

New measurements are reported for the isochoric heat capacity of the ionic liquid substance 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C6mim][NTf2]). These measurements extend the ranges of our earlier study [N.G. Polikhronidi et al., Phys. Chem. Liq. 52, 657 (2014)] by 5 % of the compressed liquid density and by 75 kelvins. An adiabatic calorimeter was used to measure one-phase

Thermal waves are caused by pure diffusion: their amplitude is decreased by more than a factor of 500 within a propagation distance of one wavelength. The diffusion equation, which describes the temperature as a function of space and time, is linear. For every linear equation the superposition principle is valid, which is known as Huygens principle for optical or mechanical wave fields. This limits

In this work the measured variable, such as temperature, is a random variable showing fluctuations. The loss of information caused by diffusion waves in non-destructive testing can be described by stochastic processes. In non-destructive imaging, the information about the spatial pattern of a samples interior has to be transferred to the sample surface by certain waves, e.g., thermal waves. At the

The purpose of this research was to investigate the sensitivity of a system for the detection of circulating melanoma cells based on the thermoelastic properties of melanoma. The method employs photoacoustic (PA) excitation coupled with an optical transducer capable of determining the presence of cells within the circulating system in vitro. The transducer is based on stress wave-induced changes of

A pairwise preferential interaction model (PPIM), based on Kirkwood-Buff integrals, is developed to quantify and characterize the interactions between some of the functional groups commonly observed in peptides. The existing experimental data are analyzed to determine the preferential interaction (PI) parameters for different amino acid and small peptide systems in aqueous solutions. The PIs between

In the standard reference equation of state for the thermodynamic properties of water, known as IAPWS-95, the fourth virial coefficient D(T) becomes abnormally large in magnitude at temperatures below approximately 300 K. At conditions where a virial expansion using only second and third virial coefficients should be essentially exact (such as vapors at pressures near 100 Pa or 1000 Pa), such a truncated