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The anisotropic structure of wood will lead to a macroscopic anisotropic property in both mechanical strength and heat transfer. Previous experimental studies of wood materials were mainly focused on the mechanical property while their anisotropic thermal property in different environments is not sufficient. In this research, the anisotropic thermal performance of spruce wood is studied at different temperature, humidity, and mechanical load. The one-dimensional steady-state method and the transient plane source method are adopted to conduct the test. The thermal conductivity in both radial and longitudinal directions of spruce wood at temperature ranging from 25 °C to 422 °C, relative humidity ranging from 30 to 90 % RH, and mechanical load ranging from 0 to 20 MPa are obtained. The accuracy of the TPS method is validated using the 1D steady-state method. Both methods can be utilized to gauge the anisotropic thermal conductivity of spruce wood. Due to the unidirectional distribution of fiber, spruce wood has a longitudinal thermal conductivity that is roughly three times greater than its radial thermal conductivity. Among environmental conditions of temperature, humidity, and mechanical load, the thermal conductivity of spruce wood is varied with temperature more significantly, which is followed by humidity and mechanical load. The measurement uncertainty is also discussed. [ABSTRACT FROM AUTHOR]

High-performance thermal insulations (HPI) have outstanding thermal properties minimizing heat transfer for a particular application. The term "high performance" is a relative assessment: whether an insulating property for a material or material system, i.e. the thermal conductivity or thermal transmittance, is significantly lower than for conventional insulating materials or systems depends on the use case and the associated conditions. Fields of applications for thermal insulations include energy, construction, industry and transport sector, as well as space and aviation industries. The total effective thermal conductivity of evacuated HPI depends on the contributions of the heat transfer via the solid skeleton of the porous insulation material and radiative heat exchange. At a given operating temperature, the effective thermal conductivity results in a minimum that depends on the density and the infrared-optically extinction properties of the insulation material. Examples for HPI with outstanding low thermal conductivity values are presented and compared with the theoretical predictions based on a percolation model for the solid thermal conductivity of the skeleton and on a diffusion model for the radiative heat transfer. [ABSTRACT FROM AUTHOR]

Knowledge about the thermal properties of human teeth is imperative for accurate understanding of heat transfer in dentistry. Despite the presence of specific heat in thermal conduction and heat transfer equations, and requiring this parameter for calculation of conductivity based on diffusivity, adequate attention has not been paid to experimental assessment of specific heat of the human enamel and dentin. Specific heat can be a temperature-dependent property. Thus, this study aimed to assess the specific heat of the human enamel, sound dentin, and carious dentin at 20 °C to 70 °C temperature (which is the realizable temperature range in dental procedures) using the differential scanning calorimetry (DSC). The results showed that the specific heat of the enamel, sound dentin and carious dentin increased with temperature rise. The specific heat of the enamel, sound dentin and carious dentin at 20 °C to 70 °C ranged from 709 J·kg−1·K−1 to 921 J·kg−1·K−1, 880 J·kg−1·K−1 to 1139 J·kg−1·K−1 and 951 J·kg−1·K−1 to 1311 J·kg−1·K−1, respectively. [ABSTRACT FROM AUTHOR]

In present work, semiconducting iron (III) oxide (Fe2O3) nanoparticles have been synthesized by sol–gel method. X-ray diffraction (XRD), UV–Visible (UV–Vis) absorption spectroscopy and transmission electron microscopy (TEM) have been used for the characterization of the synthesized nanoparticles. Two-step technique was used to formulate stable ethylene glycol (EG) based Fe2O3 nanofluids at room temperature. Thermal conductivity of nanofluids has been measured using hot disc thermal constants analyzer. Significant enhancement in the thermal conductivity is noted at very low nanoparticle loading (up to 1 wt%). Ultrasonic velocity and ultrasonic attenuation in the prepared nanofluids were investigated using an ultrasonic interferometer and acoustic particle sizer (APS-100), respectively. APS-100 was also used for the analysis of particle size distribution (PSD) of Fe2O3 nanoparticles in the prepared nanofluids. The PSD result of APS-100 has been found in good agreement with that of TEM. The characteristics behaviour of Fe2O3 nanofluid has been illustrated based on its ultrasonic and thermal properties. Our investigations advocate that Fe2O3 nanofluids have potential application for effective heat transfer management in various cooling industries. [ABSTRACT FROM AUTHOR]

The effective thermal conductivity (ETC) of particle beds has been shown to be anisotropic under uniaxial compression. The objective of this study is to validate the assumption that vertical and horizontal effective thermal conductivities of particle beds under uniaxial (vertical) compression can be correlated to compressive stresses in each direction. The horizontal compressive pressure, which is perpendicular to the applied compressive pressure, can be calculated with the use of the at-rest pressure coefficient and subsequently used in a modified macro-contact thermal resistance model to predict the horizontal ETC. The vertical ETC is obtained using the same model by substituting the vertical compressive pressure into the macro-contact thermal resistance. The modified model prediction is shown to match well with experimental data of both vertical and horizontal ETCs of particle beds under uniaxial compression in air and vacuum. [ABSTRACT FROM AUTHOR]

A collocation spectral method (CSM) is developed to solve the fin heat transfer in triangular, trapezoidal, exponential, concave parabolic, and convex geometries. In the thermal process of fin heat transfer, fin dissipates heat to environment by convection and radiation; internal heat generation, thermal conductivity, heat transfer coefficient, and surface emissivity are functions of temperature; ambient fluid temperature and radiative sink temperature are considered to be nonzero. The temperature in the fin is approximated by Chebyshev polynomials and spectral collocation points. Thus, the differential form of energy equation is transformed into the matrix form of algebraic equation. In order to test efficiency and accuracy of the developed method, five types of convective-radiative fins are examined. Results obtained by the CSM are assessed by comparing available results in references. These comparisons indicate that the CSM can be recommended as a good option to simulate and predict thermal performance of the convective-radiative fins. [ABSTRACT FROM AUTHOR]

The need for characterization of thermophysical properties of steel and nickel-based alloys was addressed in the FFG-Bridge Project 810999 in cooperation with a partner from industry, Böhler Edelstahl GmbH & Co KG. To optimize numerical simulations of production processes, such as remelting or plastic deformation, additional, and more accurate data were necessary for the alloys under investigation. With a fast ohmic pulse heating circuit system, the temperature-dependent specific electrical resistivity, density, and specific heat capacity for a set of five high alloyed steels were measured. Hence, using the Wiedemann-Franz law with a Lorenz number of $$L =2.45\times 10^{-8}\,\hbox {V}^{2}{\cdot }\hbox {K}^{-2}$$ , the thermal diffusivity and thermal conductivity could be calculated for the solid and liquid phases up to temperatures of 2500 K. This experimental approach is limited by the following requirements for the specimens: they have to be electrically conducting, the melting point has to be high enough for the implemented pyrometric temperature measurement, and one has to be able to draw wires of the material. The latter restriction is technologically challenging with some of the materials being very brittle. For all samples, electrical and temperature signals are recorded and a fast shadowgraph method is used to measure the volume expansion. For each material under investigation, a set of data including the chemical composition, the density at room temperature, solidus and liquidus temperatures, and the change of enthalpy, resistivity, density, thermal conductivity, and thermal diffusivity as a function of temperature is reported. [ABSTRACT FROM AUTHOR]

The cobalt-carbon (Co-C) eutectic point at $$1324\,^{\circ }\hbox {C}$$ has in previous studies proved to be suitable as a reference for thermocouple calibration above $$1100\,^{\circ }\hbox {C}$$ . For types S, R, and B, it fills the gap between the copper point and the palladium point, and for Pt/Pd thermocouples, it extends the range from the copper point. This work describes the implementation of the Co-C reference point at the Technical Institute of Sweden (SP). A Co-C cell was developed and manufactured at SP in a collaboration project with the National Metrology Institute of Japan (NMIJ). The principle of the cell is a hybrid design with double walls, both for the outer crucible and the inner thermometer well, with graphite foil between the walls. To evaluate the performance of the developed cell (SP cell), a comparison between the SP cell and another cell, manufactured and provided from the National Physics Laboratory (NPL) in England, is performed using Pt/Pd thermocouples as transfer standards. The comparison showed very good agreement, with differences below 40 mK, using the same furnace and two different thermocouples. The expanded uncertainty $$(k=2)$$ for the comparison was estimated to be 70 mK. [ABSTRACT FROM AUTHOR]

New Asia Pacific Metrology Programme (APMP) comparisons of radiation thermometry standards, APMP TS-11, and -12, have recently been initiated. These new APMP comparisons cover the temperature range from $$156\,^{\circ }\hbox {C}$$ to $$2800\, ^{\circ }\hbox {C}$$ . Three radiation thermometers with central wavelengths of 1.6 $$\upmu \hbox {m}$$ , 0.9 $$\upmu \hbox {m}$$ , and 0.65 $$\upmu \hbox {m}$$ are the transfer devices for the radiation thermometer scale comparison conducted in the so-called star configuration. In parallel, a compact fixed-point blackbody furnace that houses six types of fixed-point cells of In, Sn, Zn, Al, Ag, and Cu is circulated, again in a star-type comparison, to substantiate fixed-point calibration capabilities. Twelve APMP national metrology institutes are taking part in this endeavor, in which the National Metrology Institute of Japan acts as the pilot. In this article, the comparison scheme is described with emphasis on the features of the transfer devices, i.e., the radiation thermometers and the fixed-point blackbodies. Results of preliminary evaluations of the performance and characteristic of these instruments as well as the evaluation method of the comparison results are presented. [ABSTRACT FROM AUTHOR]

Measurement of moisture in materials presents many challenges, due to diverse measuring principles, sample interactions with atmosphere, and variation in what is measured (either water content alone or moisture including other liquids). Calibrations are variously referenced to published standard methods, primary calibration facilities, or certified reference materials, but each of these addresses limited substances and ranges of measurement. Overall, metrology infrastructure is not as fully developed or coherent for this field as it is for many other areas of measurement. In order to understand the metrology needs and to support developments, several European national metrology institutes (NMIs) have undertaken some collaborative activities. These have included a 'cooperation in research' project for sharing of information, a survey of moisture capabilities at NMIs, the formulation of a strategy for moisture metrology at the NMI level, and a funded research project to develop improved metrology for the moisture field. This paper summarizes the information gathered, giving an overview of the status of moisture metrology at NMIs, and it reports a proposed strategy to improve the current situation. [ABSTRACT FROM AUTHOR]

A new advanced technique was developed at the Hungarian Metrological Institute (MKEH), devoted to optimizing the realization of the International Temperature Scale ITS-90. The work was performed within the framework of the European project 'Novel techniques for traceable temperature dissemination.' The paper is devoted to describing this new measurement technique and its setup. The time evolution of the solid fraction and melt fraction along the phase transformation has been followed, using a technique based on the difference of the electrical conductivity between the solid and liquid phases of the metal. The measurement technique provides electrical signals, which are suitable for improving the quality of the freezing plateaus realized in the case of different fixed-point realizations, covering the temperature range from $$-39\,^{\circ }\mathrm{C}$$ to $$962\,^{\circ }\mathrm{C}$$ . The ideal section of the freezing plateau can be maintained by ensuring a continuous flow of mass and energy of the fixed-point substance in the axial direction. The intervention is achieved by modifying the temperatures of the different zones of the furnace controller with more degrees, with the aid of developed intervening devices. Recent developments permit the selection of the ideal section of a freezing plateau and, what is more, the increase of this plateau section to practically unlimited for all metal fixed points. [ABSTRACT FROM AUTHOR]

For a number of applications in control and safety value monitoring, a profound knowledge of the dynamic behavior of process temperature sensors is of great importance. Sensor test procedures and model identification methods are state of the art for small temperature changes, i.e., steps. For wider temperature ranges, the temperature dependency of the material characteristics is significant, too. The resulting non-linearities limit the utilization of classical model concepts. In this paper, we introduce and solve a non-linear ordinary differential equation for the linear dependency of the material characteristic parameters, i.e., for the basic case of non-constant material parameters. The analytic solution will be explained, and the results are discussed and compared to a finite element method model of a basic cylinder. [ABSTRACT FROM AUTHOR]

The growing demand of industry for traceable temperature measurements up to $$3000\,^{\circ }\hbox {C}$$ encourages improvement of calibration techniques for industrial-type radiation thermometers in this temperature range. High-temperature fixed points can be used at such high temperatures, but due to the small diameter of apertures of their cavities ( $${\sim }$$ 3 mm), they are not adapted for the large field-of-views commonly featured by this kind of radiation thermometers. At LNE-Cnam, a Thermo Gauge furnace of 25.4 mm source aperture diameter is used as a comparison source to calibrate customers' instruments against a reference radiation thermometer calibrated according to the ITS-90 with the lowest uncertainties achievable in the Laboratory. But the furnace blackbody radiator exhibits a large temperature gradient that degrades its effective emissivity, and increases the calibration uncertainty due to the lack of information on the working spectral band of the industrial radiation thermometer. In order to estimate the corrections to apply, the temperature distribution (radial and on-axis) of the Thermo Gauge furnace blackbody radiator was characterized and the effective emissivity of the Thermo Gauge cavity was determined by three different methods. Because of this investigation, the corrections due to different fields of view and due to the different spectral bands of the reference pyrometer and the customer's pyrometer were obtained and the uncertainties on these corrections were evaluated. [ABSTRACT FROM AUTHOR]

Impurities are still among the primary concerns regarding the realization of many fixed points of the International Temperature Scale (ITS-90). Several methods have been suggested to correct for these effects. The most promising strategy, with regard to the achievable uncertainty level, is the 'sum of the individual estimates' (SIE) method. It involves a chemical analysis of the material and a calculation of each of the detected chemical species' effect on the phase-transition temperature of the fixed-point substance. This correction can be accurate only if all the detected impurities are completely dissolved. Given the recent evidence for insoluble impurities in metal fixed points, this strategy needs to be modified; otherwise, it may lead to an inaccurate estimation of the impurity-related effect on the fixed-point temperature. In this article, a correction method is set out that reflects the crucial distinction between soluble, insoluble, and partially soluble impurities. This 'sum of the individual estimates for the dissolved species' (SIEDS) method starts from a chemical analysis but takes into account only the dissolved particles. For this purpose, different types of substances are considered as possible dissolved impurities and are discussed from a chemical point of view. For those impurities where data are insufficient, only an uncertainty estimation is possible. For this purpose, the 'overall maximum estimate of the dissolved species' (OMEDS) method is derived from the SIEDS method as the new counterpart to the well-known 'overall maximum estimate' (OME) method. [ABSTRACT FROM AUTHOR]

The aim of this paper is to describe the evaluation process of the performance of the low-range saturator (LRS), when exposed to two different thermal environments. The examined saturator was designed, built, and tested at MIKES (Centre for Metrology and Accreditation, Finland), and then transported to the Laboratory for Process Measurement (LPM) in Croatia, where it was implemented in a new dew-point calibration system. The saturator works on a single-pressure-single-pass generation principle in the dew/frost-point temperature range between $$-70\,^{\circ }\hbox {C}$$ and $$+5\,^{\circ }\hbox {C}$$ . The purpose of the various tests performed at MIKES was to examine the efficiency and non-ideality of the saturator. As a test bath facility in Croatia differs from the one used in Finland, the same tests were repeated at LPM, and the effects of different thermal conditions on saturator performance were examined. Thermometers, pressure gauges, an air preparation system, and water for filling the saturator at LPM were also different than those used at MIKES. Results obtained by both laboratories indicate that the efficiency of the examined saturator was not affected either by the thermal conditions under which it was tested or by equipment used for the tests. Both laboratories concluded that LRS is efficient enough for a primary realization of the dew/frost-point temperature scale in the range from $$-70\,^{\circ }\hbox {C}$$ to $$+5\,^{\circ }\hbox {C}$$ , with flow rates between $$1\hbox { L}{\cdot }\hbox {min}^{-1}$$ and $$2.5\hbox { L}{\cdot }\hbox {min}^{-1}$$ . It is also shown that a considerable difference of the pre-saturator efficiency, indicated by two laboratories, did not have influence to the overall performance of the saturator. The results of the research are presented in graphical and tabular forms. This paper also gives a brief description of the design and operation principle of the investigated low-range saturator. [ABSTRACT FROM AUTHOR]

A multi-partner project to determine the thermodynamic temperatures of a selected set of high-temperature fixed points based on metal-carbon eutectics is underway as a working group activity within the Comité International des Poids et Mesures. The investigation focuses on four fixed-point types, namely, the three metal-carbon eutectic points of Re-C $$(2474\,^{\circ }\hbox {C})$$ , Pt-C $$(1738\,^{\circ }\hbox {C})$$ , and Co-C $$(1324\,^{\circ }\hbox {C})$$ , and the Cu point $$(1084.62\,^{\circ }\hbox {C})$$ . This paper describes the construction, pre-evaluation, and screening stage of the cells prior to their thermodynamic temperature determinations. The construction of the HTFP cells was undertaken by nine national metrology institutes (NMIs) according to instructions laid out in a pre-agreed protocol that ensures production of best quality cells. Four NMIs conducted the evaluation, each for a certain fixed-point type, and screened out cells that did not meet pre-determined selection criteria while assuring sufficient variety in the sources of the cells in the final selected sets. In autumn 2012, the selected cells were successfully passed on to the final stage of the project, the thermodynamic temperature measurement, and assignment. [ABSTRACT FROM AUTHOR]

First-principles calculations have been performed to obtain the thermodynamic properties of $$\hbox {ScAlO}_{3}$$ perovskite in a wide range of pressure (0 GPa to 30 GPa) and temperature (0 K to 1400 K). Calculations have been performed by using the pseudo-potential method within the generalized gradient approximation. Both pressure- and temperature-dependent thermodynamic properties including the bulk modulus, thermal expansion, thermal expansion coefficient, and the heat capacity at constant volume and constant pressure were calculated using three different approaches based on the quasi-harmonic Debye model: the Slater, Dugdale-MacDonald (DM), and Vaschenko-Zubarev (VZ) approaches. Also, empirical energy corrections are applied to the results of models to correct the systematic errors introduced by the functional. It is found that the VZ model provides more accurate estimates in comparison with the DM and Slater models, especially after an empirical energy correction. The results obtained from the VZ analysis on the corrected static energy show that this method can be used to determine the thermodynamic properties of $$\hbox {ScAlO}_{3}$$ compounds with reasonable accuracy. [ABSTRACT FROM AUTHOR]

Calibration of infrared radiation thermometers at non-unity emissivity settings is a poorly solved problem for establishment of traceability to meet user needs, for instruments with both fixed and variable emissivity setting functions. A variable-temperature gray-body radiator having a constant value of emissivity independent of both wavelength and temperature can be a perfect tool for the calibration purpose. In this paper, two types of high-transmittance optical neutral density filters, one utilizing a rotating-sector optical chopper, and another of a wire-mesh type, are shown to perform well with a precise transmittance between 90 % and 100 % in the wide infrared wavelength range. These optical filters in combination with a blackbody cavity traceable to ITS-90 can realize reliable gray-body radiation. These methods are applied successfully to several models of infrared thermometers operated in the emissivity correction mode. [ABSTRACT FROM AUTHOR]

A recently assembled setup to measure the spectral emissivity at elevated temperatures above 1000 K is described in detail. It is based on a commercial laser-flash apparatus, which has been substantially modified to measure both the laser pulse energy-leading to the pulse heating of the specimen-and the resulting temperature rise. For these measurements the laser beam was characterized with respect to its spatial energy distribution. The temperature rise itself is detected by a specially designed, fast-response radiation thermometer with a spectral responsivity at the wavelength of the laser radiation of 1064 nm. Additional corrections have been investigated to correct the measured temperature radiation for the influence of the hot surrounding furnace. Also, the non-adiabatic temperature rise is corrected with a for the measurement of the thermal diffusivity established fitting function. First measurement results for the normal spectral emissivity of isostatic-pressed graphite between 1000 K and 1800 K are presented. [ABSTRACT FROM AUTHOR]

$$^{3}$$ He interpolating constant-volume gas thermometer scales are compared using different virial coefficients and gas densities for a temperature range of 3 K to the triple point of Ne (24.5561 K). The differences between the International Temperature Scale of 1990 (ITS-90) and the interpolation scale, which follows the definition of the ITS-90 but uses the second and third virial coefficients of the recent ab initio calculations, have maxima of about 0.08 mK and 0.13 mK for gas densities of $$168\,\hbox {mol}{\cdot }\hbox {m}^{-3}$$ and $$278\,\hbox {mol}{\cdot }\hbox {m}^{-3}$$ , respectively. The differences between the ITS-90 and the interpolation scale using only the ab initio second virial coefficient have maxima of about 0.08 mK and 0.14 mK for the same respective sequence of gas densities. The ITS-90 temperatures obtained in eight runs with gas densities from $$127\,\hbox {mol}{\cdot } \hbox {m}^{-3}$$ to $$278\,\hbox {mol}{\cdot }\hbox {m}^{-3}$$ agree with a polynomial of the resistance of a rhodium-iron resistance thermometer within 0.2 mK. To calculate the temperature profile along the pressure-sensing tube connecting the low temperature part of the constant-volume gas thermometer to room temperature, a calculation model is proposed that takes into account not only the thermal conductivity of the tube wall but also the radiative heat transfer between the tube and the vacuum jacket enclosing it. The calculation results of this model approximate the measured profile better than the conventional calculations that neglect the radiative heat transfer. [ABSTRACT FROM AUTHOR]

At the national facility for blackbody source radiance temperature calibration of the National Institute of Metrology, China, a stirred liquid bath blackbody was developed for use as a radiance temperature reference source, which has a temperature range from $$-30\,^{\circ }\hbox {C}$$ to $$80\,^{\circ }\hbox {C}$$ . This blackbody source consists of a stirred liquid bath, a blackbody cavity, a standard capsule platinum resistance thermometer, and a dry-air purging system. The cavity is cylindrical with $$31^{\circ }\,\hbox {V}$$ grooves on the inner wall. The cavity is 80 mm in diameter, with a depth of 520 mm, and is immersed in a bath filled with a water-ethylene glycol mixture. The average normal emissivity of the cavity is calculated to be better than 0.9999 with V grooves and when painted with Nextel 811-21 coating. The temperature stability of the blackbody source is $$0.005\,^{\circ }\hbox {C}$$ over a period of 20 min, and the temperature uniformity of the cavity bottom is $$0.02\,^{\circ }\hbox {C}$$ . The standard uncertainty of the radiance temperature of the stirred liquid bath blackbody source is estimated to be $$0.013\,^{\circ }\hbox {C}$$ . [ABSTRACT FROM AUTHOR]

Application of radiation thermometry in industrial scenes is rapidly increasing with the widespread use of low-cost infrared thermometers and thermal imagers. However, their performances are not always up to the users' expectations. This is often due to lack of appropriate information on the limitations of the instrument performance and of radiation thermometry itself. In this article, these limitations are disclosed, namely the targeting capabilities of the thermometers including the size-of-source effect of thermal imagers, reflection errors, and unknown emissivity of the measurement object. Attempts made at the NMIJ are introduced, which aim at alleviating the effect of these difficulties. Two-color radiation thermometers have been neglected from the traceability chain and from standardization efforts due to their technical complexity. Recent activities to incorporate them effectively in the calibration chain and to establish international standards are presented. Calibration of low-cost thermometers with a fixed instrumental emissivity setting has been an issue for calibration laboratories. Simple apparatus that enables calibration of such instruments is described. Methods to compensate for unknown emissivities are presented utilizing auxiliary sources to realize a blackbody condition, which is applied to thermal imagers to overcome the problem of the size-of-source effect and reflection error at the same time. Extensions of the technique to objects with specular and scattering surfaces are described. Such efforts are encouraged in the thermometry community since they are essential in establishing an unbroken chain of traceability to the industrial front. [ABSTRACT FROM AUTHOR]

The triple-point temperature of neon, $$T_{\mathrm{tp-Ne}}$$ , is known to have dependence on the isotopic composition. Recently, the Technical Annex for the International Temperature Scale of 1990 was updated to specify the method of correction for the isotopic reference ratio of neon. In this study, to confirm this correction in the Technical Annex independently, the effects of the isotopic composition of neon on $$T_{\mathrm{tp-Ne}}$$ for three commercial neon gas sources were studied. For the measurement of the isotopic composition, a gas mass spectrometer was used to compare the sample gases with a reference neon gas whose isotopic composition was known with high precision by a gravimetric method. For the measurement of $$T_{\mathrm{tp-Ne}}$$ , an open-cell type cryostat for the realization of low-temperature fixed points was used. The physical cell and the thermal environment around it remained very similar for all $$T_{\mathrm{tp-Ne}}$$ measurements with the neon gases due to the nature of the open-cell type system. Therefore, the difference in $$T_{\mathrm{tp-Ne}}$$ among different samples could be measured with a relatively low uncertainty, canceling many systematic effects that are common to all measurements. Our result was consistent with the correction in the Technical Annex. Furthermore, because one of the commercial neon gases was the bottle that was used for KRISS measurements in the international comparison CCT-K2, it is now possible to correct the measurement for the reference isotopic ratio and compare it with other measurements for which isotopic composition data are available. [ABSTRACT FROM AUTHOR]

The worldwide history and present state of development of rhodium-iron resistance thermometers (RIRTs) is briefly reviewed. A standardized interpolation method using RIRTs with the nominal composition of 0.5 % Fe (by mole) is presented, with examples using data taken from 60 RIRTs made from a variety of wire batches and sources worldwide over the last 40 years. The parameterization exploits the favorable characteristics of the Cragoe reduced resistance $$Z(\tau )$$ and a suitably reduced temperature $$\tau $$ . A reference function $$Z_\mathrm{ref}(\tau )$$ which approximates the average characteristics of selected wire is derived for use over the interval 0.65 K to 24.5561 K on the ITS-90. The deviations of real RIRT data from this reference function are examined, and simple four-parameter Fourier-series solutions for the resulting deviation curves are presented. Despite the fact that the wire samples may be of different origins or state-of-anneal, it was found that the interpolations are successful for most of the samples studied over the 4.2 K to 24.5561 K interval, at the level of $$\approx $$ 1 $$\hbox {mK}$$ standard uncertainty or less. This method would allow for calibrations of most RIRTs over this interval using only six calibration points, permitting an efficiency not achievable using the common least-squares curve-fitting calibration methods. The potential of this formalism for a standardized interpolation scheme using RIRTs is discussed. [ABSTRACT FROM AUTHOR]

Techniques for the evaluation of the spatial temperature and humidity performance criteria of climatic chambers are described within the various sections of the International Electrotechnical Commission (IEC) Standard IEC60068 applicable to environmental testing. This paper involves the comparison of three common measurement systems used to assess the performance of climatic chambers, as well as the development of methods for determination of uncertainty contributions, and subsequent propagation into an uncertainty analysis for each method. Methods for validating the performance of these chambers should include specific uncertainty contributions, such as fluctuations, homogeneity, radiation, sampling, and loading effects. These effects are discussed and evaluated as part of this work. The procedure, as detailed in IEC60068, was followed using a chilled-mirror dew-point hygrometer with nine platinum resistance thermometers, nine calibrated RH (relative humidity) and temperature probes, and nine calibrated RH and temperature wireless data logger modules. Loading effect and dew-point uniformity were evaluated empirically and the results discussed. A summary of the results obtained and the associated uncertainty calculations are described and compared. All three systems have their merits, and lower uncertainties in both temperature and %rh were obtained for the chilled-mirror system. [ABSTRACT FROM AUTHOR]

Thermocouples are prone to significant drift in use particularly when they are exposed to high temperatures. Indeed, high-temperature exposure can affect the response of a thermocouple progressively by changing the structure of the thermoelements and inducing inhomogeneities. Moreover, an oxidizing atmosphere contributes to thermocouple drift by changing the chemical nature of the metallic wires by the effect of oxidation. In general, severe uncontrolled drift of thermocouples results from these combined influences. A periodic recalibration of the thermocouple can be performed, but sometimes it is not possible to remove the sensor out of the process. Self-validation methods for thermocouples provide a solution to avoid this drawback, but there are currently no high-temperature contact thermometers with self-validation capability at temperatures up to $$1600\,^{\circ }\hbox {C}$$ . LNE-Cnam has developed fixed-point devices integrated to the thermocouples consisting of machined alumina-based devices for operation under oxidizing atmospheres. These devices require small amounts of pure metals (typically less than 2 g). They are suitable for self-validation of high-temperature thermocouples up to $$1600\,^{\circ }\hbox {C}$$ . In this paper the construction and the characterization of these integrated fixed-point devices are described. The phase-transition plateaus of gold, nickel, and palladium, which enable coverage of the temperature range between $$1000\,^{\circ }\hbox {C}$$ and $$1600\,^{\circ }\hbox {C}$$ , are assessed with this self-validation technique. Results of measurements performed at LNE-Cnam with the integrated self-validation module at several levels of temperature will be presented. The performance of the devices are assessed and discussed, in terms of robustness and metrological characteristics. Uncertainty budgets are also proposed and detailed. [ABSTRACT FROM AUTHOR]

This paper considers the influence, in terms of temperature and time, of the following three factors on the phase transition of high-temperature fixed points: the temperature gradient of the furnace along the fixed-point cell, the thermal inertia of the furnace, and the thermal condition of the cell itself. Melting and freezing experiments have been performed for the eutectic Co-C in a three-zone furnace, of which the temperature gradient along the cell could be varied from positive to negative. To help the interpretation of these experiments, a realistic 2D finite-element model has been implemented, simulating the three influence factors. The model allowed us to understand the features observed in the melts and associated freezes, for the different furnace conditions, not only qualitatively but also quantitatively. This research identifies the essential requirements to facilitate the optimum configuration of the furnace and cell design. [ABSTRACT FROM AUTHOR]

In this paper, an interlaboratory comparison in the field of the measurement of temperature is presented. The purpose of the interlaboratory comparison described here is to compare the capabilities for the calibration of a standard platinum resistance thermometer (SPRT) at fixed points in the range from the triple point of mercury $$(-38.8344\,{}^{\circ }\hbox {C})$$ to the freezing point of zinc $$(419.527\,{}^{\circ }\hbox {C})$$ . Results are used to support the process of accepting calibration and measurement capabilities. The interlaboratory comparison was organized by the University of Ljubljana, Faculty of Electrical Engineering, Laboratory of Metrology and Quality (MIRS/UL-FE/LMK). The circulated artifact was a $$25 \,\Omega $$ metal-sheathed SPRT. The interlaboratory comparison included three fixed points of the International Temperature Scale of 1990 (mercury, tin, and zinc) in the range between $$-38\,{}^{\circ }\hbox {C}$$ and $$420\,{}^{\circ }\hbox {C}$$ . Prior to the start of measurements, annealing was performed in accordance with protocol. MIRS/UL-FE/LMK performed measurements at the beginning of the interlaboratory comparison and at the end. Prior to the calibration at fixed points in each laboratory, a test measurement at the triple point of water was done in order to assess the stability of the traveling SPRT. It was recommended that the participants use their standard procedure for the calibration of the SPRT at each fixed point and follow instructions from the protocol during the temperature calibration. The results of $$W$$ at each fixed point for both laboratories are summarized, and they agree within their expanded uncertainties. [ABSTRACT FROM AUTHOR]

International Standard ISO 7730:2005 defines thermal comfort as that condition of mind that expresses the degree of satisfaction with the thermal environment. Although this definition is inevitably subjective, the Standard gives formulae for two thermal comfort indices, predicted mean vote ( PMV) and predicted percentage dissatisfied ( PPD). The PMV formula is based on principles of heat balance and experimental data collected in a controlled climate chamber under steady-state conditions. The PPD formula depends only on PMV. Although these formulae are widely recognized and adopted, little has been done to establish measurement uncertainties associated with their use, bearing in mind that the formulae depend on measured values and tabulated values given to limited numerical accuracy. Knowledge of these uncertainties are invaluable when values provided by the formulae are used in making decisions in various health and civil engineering situations. This paper examines these formulae, giving a general mechanism for evaluating the uncertainties associated with values of the quantities on which the formulae depend. Further, consideration is given to the propagation of these uncertainties through the formulae to provide uncertainties associated with the values obtained for the indices. Current international guidance on uncertainty evaluation is utilized. [ABSTRACT FROM AUTHOR]

A new laser-based technique to examine heat transfer and energetics of phase transitions in metal-carbon fixed points and potentially to improve the quality of phase transitions in furnaces with poor uniformity is reported. Being reproducible below 0.1 K, metal-carbon fixed points are increasingly used as reference standards for the calibration of thermocouples and radiation thermometers. At NMIA, the Co-C eutectic point is used for the calibration of thermocouples, with the fixed point traceable to the International Temperature Scale (ITS-90) using radiation thermometry. For thermocouple use, these cells are deep inside a high-uniformity furnace, easily obtaining excellent melting plateaus. However, when used with radiation thermometers, the essential large viewing cone to the crucible restricts the furnace depth and introduces large heat losses from the front furnace zone, affecting the quality of the phase transition. Short $$\hbox {CO}_{2}$$ laser bursts have been used to illuminate the cavity of a conventional Co-C fixed-point cell during various points in its melting phase transition. The laser is employed to partially melt the metal at the rear of the crucible providing a liquid-solid interface close to the region being observed by the reference pyrometer. As the laser power is known, a quantitative estimate of $$(166 \pm 30) \hbox { J}{\cdot }\hbox {g}^{-1}$$ can be made for the Co-C latent heat of fusion. Using a single laser pulse during a furnace-induced melt, a plateau up to 8 min is observed before the crucible resumes a characteristic conventional melt curve. Although this plateau is satisfyingly flat, well within 100 mK, it is observed that the plateau is laser energy dependent and elevates from the conventional melt 'inflection-point' value. [ABSTRACT FROM AUTHOR]

The emissivity of most material surfaces that can be used as radiation sources is a function of wavelength. On the other hand, blackbody cavities with emissivities higher than 0.995 in a wide wavelength range are readily available in many laboratories. If it were possible to attenuate by a constant factor the radiation emitted by those blackbodies, then they could be used as gray-body radiators. A neutral density filter is not an option to attenuate the radiation from a blackbody source because its transmittance is wavelength dependent. Optical choppers, usually rotating disk shutters, are widely used to modulate the intensity of a light beam. The apparent transmittance of an optical chopper is defined in terms of the mark-to-space ratio. Most optical choppers have a 1:1 ratio which would be equivalent to 50 % transmittance. To attenuate the radiation coming from a blackbody, the optical chopper should have a stable rotating speed and a high chopping frequency so its mark-to-space cycle time is very short compared to a radiation thermometer response time. If this condition is fulfilled, the radiation thermometer would display a temperature reading as if it were aiming to a gray-body at the temperature of the blackbody and with an emissivity equal to the optical chopper transmittance. This method to obtain a gray-body radiator using a blackbody source and an optical chopper is discussed, and some measurements including its uncertainty analysis are reported. [ABSTRACT FROM AUTHOR]

Type R and Type S platinum/platinum-rhodium thermocouples are amongst the most widely used high-temperature thermocouples, both for process measurement and as reference thermocouples. To achieve the lowest practical uncertainties, below $$1\, ^{\circ }\hbox {C}$$ , the thermocouples must be in a well-defined thermoelectric state. There are two annealing procedures in common use that leave the thermocouples in different states, leading to a potential ambiguity and uncertainty. This paper reports on experiments with Type S thermocouples clearly exposing the different drift characteristics for the two different annealed states. Thermocouples used above $$800\, ^{\circ }\hbox {C}$$ show the least drift when annealed at $$1100\, ^{\circ }\hbox {C}$$ and then passively quenched to room temperature. If used at lower temperatures, they exhibit drift, at temperatures as low as $$170\, ^{\circ }\hbox {C}$$ , with the drift peaking at $$0.3\, ^{\circ }\hbox {C}$$ to $$0.4\, ^{\circ }\hbox {C}$$ around $$300\, ^{\circ }\hbox {C}$$ to $$600 \, ^{\circ }\hbox {C}$$ . Thermocouples used below $$800\, ^{\circ }\hbox {C}$$ are best annealed at $$1100\, ^{\circ }\hbox {C}$$ , and then again at $$450\, ^{\circ }\hbox {C}$$ . In this state, they exhibit practically zero drift for temperatures up to about $$600 \, ^{\circ }\hbox {C}$$ . Advice on calibration procedures to minimise the effects of drift is given. [ABSTRACT FROM AUTHOR]

Two methods for the uncertainty estimation in the dew/frost-point temperature and relative humidity are shown. The uncertainty estimation was performed propagating the uncertainties of pressure and temperature measurements in the corresponding equations in the classic method, and propagating the distributions of the input variables, pressure and temperature, (Monte Carlo simulation) in an alternative method. The results obtained by the different methods are compared for analyzing the validity of the uncertainty calculations, and the assumption of negligible correlations between the input variables. The agreement between the presented uncertainty analysis and the outcomes of the comparison with INMETRO is discussed. [ABSTRACT FROM AUTHOR]

This paper deals with the thermal regulation at the $$\pm $$ 10 $$\hbox {mK}$$ level of a high-accuracy cylindricity measurement machine subject to thermal disturbances, generated by four heat sources (laser interferometers). A reduced model identified from simulated data using the modal identification method was associated with a model predictive controller (MPC). The control was applied to minimize the thermal perturbation effects on the principal organ of the cylindricity measurement machine. A parametric study of the penalization coefficient $$\lambda $$ was conducted, which validated the robustness of the controller. The association of both reduced model and MPC allowed significant reduction of the effects of the disturbances on the temperature, a promising result for future applications. [ABSTRACT FROM AUTHOR]

The KRISS low frost-point humidity generator which has been operated by the two-temperature method in the frost-point range from $$-95\,^{\circ }\hbox {C}$$ to $$-40\,^{\circ }\hbox {C}$$ since 2006 is reformed to a two-temperature, two-pressure type, in order to extend the calibration capability to a frost point of $$-105\,^{\circ }\hbox {C}$$ . The temperature and pressure of the saturator were controlled to $$-95\,^{\circ }\hbox {C}$$ and 1 MPa, respectively. The water-vapor mole ratio generated by the upgraded humidity generator reached $$4\,\hbox {nmol}{\cdot }\hbox {mol}^{-1}$$ . The uncertainty of the generator was estimated by calculations as well as a series of experiments including the stability of the generated frost point, the saturation efficiency with a varied gas flow rate, and the change of water-vapor mole ratio in the tubing line. The standard uncertainty of the generator is less than $$0.09\,^{\circ }\hbox {C}$$ at the frost point of $$-95\,^{\circ }\hbox {C}$$ and is increased to $$0.19\,^{\circ }\hbox {C}$$ at the frost point of $$-105\,^{\circ }\hbox {C}$$ . The increase in uncertainty is mainly due to the water adsorption/desorption on the internal surface of tubing from the saturator to the hygrometer. [ABSTRACT FROM AUTHOR]

A CCD camera, which has been specially equipped with narrow-band interference filters in the visible spectral range for temperature measurements above 1200 K, was characterized with respect to its temperature response traceable to ITS-90 and with respect to absolute spectral radiance responsivity. The calibration traceable to ITS-90 was performed at a high-temperature blackbody source using a radiation thermometer as a transfer standard. Use of Planck's law and the absolute spectral radiance responsivity of the camera system allows the determination of the thermodynamic temperature. For the determination of the absolute spectral radiance responsivity, a monochromator-based setup with a supercontinuum white-light laser source was developed. The CCD-camera system was characterized with respect to the dark-signal-non-uniformity, the photo-response-non-uniformity, the non-linearity, and the size-of-source effect. The influence of these parameters on the calibration and measurement was evaluated and is considered for the uncertainty budget. The results of the two different calibration schemes for the investigated temperature range from 1200 K to 1800 K are in good agreement considering the expanded uncertainty $$(k= 2)$$ . The uncertainty for the absolute spectral responsivity of the camera is 0.56 % $$(k= 2)$$ . [ABSTRACT FROM AUTHOR]

We consider a problem of constructing the exact and/or approximate coverage intervals for the common mean of several independent distributions. In a metrological context, this problem is closely related to evaluation of the interlaboratory comparison experiments, and in particular, to determination of the reference value (estimate) of a measurand and its uncertainty, or alternatively, to determination of the coverage interval for a measurand at a given level of confidence, based on such comparison data. We present a brief overview of some specific statistical models, methods, and algorithms useful for determination of the common mean and its uncertainty, or alternatively, the proper interval estimator. We illustrate their applicability by a simple simulation study and also by example of interlaboratory comparisons for temperature. In particular, we shall consider methods based on (i) the heteroscedastic common mean fixed effect model, assuming negligible laboratory biases, (ii) the heteroscedastic common mean random effects model with common (unknown) distribution of the laboratory biases, and (iii) the heteroscedastic common mean random effects model with possibly different (known) distributions of the laboratory biases. Finally, we consider a method, recently suggested by Singh et al., for determination of the interval estimator for a common mean based on combining information from independent sources through confidence distributions. [ABSTRACT FROM AUTHOR]

At the National Metrology Institute of Japan (NMIJ), a new monochromator-based absolute radiometric calibration system for radiation thermometers has been developed with a supercontinuum (SC) source instead of a tungsten-halogen lamp. Compared with halogen lamps, remarkably higher spectral radiance can be obtained from the SC-monochromator-based system because the SC optical radiation can be efficiently coupled into the narrow entrance slit of the monochromator, thus enabling coupling of the monochromatic light from the exit slit into an integrating sphere, which serves as a wavelength-tunable source for calibrating radiation thermometers against a reference detector. In this work, the setup and preliminary measurement results of the SC-source-based system at the NMIJ are described. Techniques for power stabilization, wavelength determination, spatial-uniformity improvement, and interference fringe reduction are applied to the system. The uncertainties of the facility for thermodynamic temperature measurements are estimated. [ABSTRACT FROM AUTHOR]

The Norwegian Metrology Service (JV) offers calibration of blackbodies, thermal imagers, and radiation thermometers to the national clients. The temperature measurements are traceable to the ITS-90 with a set of reference blackbodies covering the range from 10 °C to 1700 °C. However, between 100 °C and 300 °C we do not have a direct measurement of the cavity temperature from a traceable sensor, and rely instead on a pyrometer to provide the reference temperature. The pyrometer is regularly calibrated externally at a handful of predefined temperatures. In this work we present a calibration scheme for the pyrometer which allows calibration at the JV premises: the pyrometer is set to record the measured radiation level at predefined temperatures below 100 °C and just above 300 °C. The calibration data are used to fit a Sakuma-Hattori model, and subsequent readings of the radiation level can be input to the model to extract the corresponding temperature. We present uncertainty budgets for the calibration data, which is subsequently used to estimate a combined uncertainty at arbitrary measured temperatures between 100 °C and 300 °C. Finally, temperatures obtained with the described scheme are compared with recent calibration values obtained externally, and we show that this is a reasonable way to achieve traceable calibration of the pyrometer with adequate precision and low uncertainty. The model fitting has the added benefit of a continuous calibration curve throughout the relevant temperature range rather than at a handful of arbitrary points. [ABSTRACT FROM AUTHOR]

The international temperature scale of 1990 defines temperatures in the range from 13.8 K to 1234.93 K ( $$961.78\,^{\circ }\hbox {C}$$ ) using a standard platinum resistance thermometer (SPRT) as an interpolating instrument. For temperatures above $$660\,^{\circ }\hbox {C}$$ , the current designs of an SPRT require extreme care to avoid contamination, especially by metallic impurities, which can cause rapid and irreversible drift. This study investigates the performance of a new design of a high-temperature SPRT with the aim of improving the stability of the SPRTs and extending their temperature range. The prototype SPRTs have an alumina sheath, a sapphire support for the sensing element, which are aspirated with dry air and operated with a dc bias voltage to suppress the diffusion of metal-ion contaminants. Three prototype thermometers were exposed to temperatures near or above the copper freezing point, $$1085\,^{\circ }\hbox {C}$$ , for total exposure times in excess of 500 h and exhibited drifts in the triple-point resistance of less than 10 mK. The new design eliminates some of the problems associated with fused-silica sheaths and sensor-support structures and is a viable option for a high-accuracy thermometer for temperatures approaching $$1100\,^{\circ }\hbox {C}$$ . [ABSTRACT FROM AUTHOR]

Most commonly used, low-temperature, infrared thermometers have large fields of view sizes that make them difficult to be calibrated with narrow aperture blackbodies. Flat-plate calibrators with large emitting surfaces have been proposed for calibrating these infrared thermometers. Because the emissivity of the flat plate is not unity, its radiance temperature is wavelength dependent. For calibration, the wavelength pass band of the device under test should match that of the reference infrared thermometer. If the device under test and reference radiometer have different pass bands, then it is possible to calculate the corresponding correction if the emissivity of the flat plate is known. For example, a correction of $$0.4\,^{\circ }\hbox {C}$$ at $$500\,^{\circ }\hbox {C}$$ is required when calibrating a $$3.9\,{\upmu }\hbox {m}$$ infrared thermometer with a ' $$10\,{\upmu }\hbox {m}$$ ' radiometrically calibrated flat-plate calibrator. A method is described for using a radiometrically calibrated flat-plate calibrator that covers both cases of match and mismatch working wavelength ranges of a reference infrared thermometer and infrared thermometers to be calibrated with the flat-plate calibrator. Also, an application example is included in this paper. [ABSTRACT FROM AUTHOR]

The main problems of conventional dry block calibrators are axial temperature gradients and calibration results which are strongly influenced by the geometry and the thermal properties of the thermometers under test. To overcome these disadvantages, a new dry block calibrator with improved homogeneity of the inner temperature field was developed for temperatures in the range from room temperature up to $$600\,^{\circ }\hbox {C}$$ . The inner part of the dry block calibrator is a cylindrical normalization block which is divided into three parts in the axial direction. Between these parts, heat flux sensors are placed to measure the heat flux in the axial direction inside the normalization block. Each part is attached to a separate tube-shaped heating zone of which the heating power can be controlled in a way that the axial heat flux measured by means of the heat flux sensors is zero. Additionally, an internal reference thermometer is used to control the absolute value of the temperature inside the normalization block. To minimize the radial heat flux, an adiabatic shield is constructed which is composed of a secondary heating zone that encloses the whole assembly. For rapid changes of the set point from high to low temperatures, the design contains an additional ventilation system to cool the normalization block. The present paper shows the operating principle as well as the results of the design process, in which numerical simulations based on the finite element method were used to evaluate and optimize the design of the dry block calibrator. The final optimized design can be used to build a prototype of the dry block calibrator. [ABSTRACT FROM AUTHOR]

A three-year program of work supported by the European Commission (EC) involving eleven partners from six countries has been carried out to select, procure, characterize, and certify the thermal transport properties (thermal conductivity, λ, and thermal diffusivity, a) of Pyroceram 9606, a polycrystalline glass ceramic identified as the most suitable reference material for use up to at least 1000 °C. For the initial calibration, six blocks were chosen from a batch of 30 blocks purchased for the project. Measurements of the following properties were undertaken: chemical analysis and microstructure, density and porosity, homogeneity, anisotropy, thermal cycling between 20 °C and 1000 °C, and long-term stability and reproducibility. In addition, specific heat capacity, linear thermal expansivity, and thermal transmissivity measurements were carried out so that the thermal conductivity could also be determined from thermal-diffusivity values obtained from the certification measurements. As a result of a successful characterization program, the partners had no hesitation in recommending to the European Commission that full certification of the thermal conductivity and thermal diffusivity of Pyroceram 9606 should be undertaken. [ABSTRACT FROM AUTHOR]

The hot/cold rolled steel coil can be considered as a periodically laminated material composed of layers of steel strips and gas gaps in the radial direction. The conduction of steel, of gas, of contact points due to the surface roughness, as well as radiation have been included in a determination of the radial effective thermal conductivity. Based on the analysis of heat transfer mechanisms in radial coils, a new formula for the radial effective thermal conductivity has been derived, which depends not only on the temperature but also on the type of atmosphere gas, the surface characteristic of coils, strip thickness, and compressive stress. Using this effective conductivity, a detailed mathematical model has been developed to predict the temperature distribution of coils in a high performance hydrogen (HPH) furnace. The calculated annealing curves are in good agreement with experimental data. KEY WORDS: effective thermal conductivity; HPH furnace; heat transfer; mathematical model. [ABSTRACT FROM AUTHOR]

It is well known that the thermal performance of some insulating and building materials is related to the actual operating conditions because the thermal conductivity of such materials is highly dependent on the moisture content. Since the thermal conductivity of liquid water is about 25 times greater than that of air, it is quite easy to understand how even small variations of the moisture content can have a significant impact on thermal performance. For this reason it is important to find a correlation between the moisture content in a specimen and its thermal conductivity. The purpose of this paper is to investigate both experimentally and theoretically the moisture contribution during the measurement of the heat transfer properties in light concrete slabs (autoclaved concrete and concrete lighted with polystyrene pearls) and to correlate its thermal transmissivity with the moisture content. KEY WORDS: heat transfer; light concrete; moisture transfer; thermal conductivity; vapor. [ABSTRACT FROM AUTHOR]

Conventionally, the accuracy of predicting the CO2 geological storage capacity was limited by the assumption that the formation thermal properties along the depth of wellbore were constant. In the present paper, firstly, a numerical model aimed at investigating the effect of thermal properties on the heat transfer amount was presented and then validated by experimental data. It was found that two thermal properties, thermal conductivity and volumetric specific heat capacity, affected CO2 temperature, and the effect of thermal conductivity was greater than volumetric specific heat capacity. Secondly, a novel estimation method was presented, with which the distribution of formation thermal properties along wellbore can be acquired with the use of well logging temperature data in CO2 storage wells. The average relative error of the thermal conductivity and the volumetric specific heat capacity was less than 5 % and 10 %, respectively. With this method, the accuracy of numerical study on CO2 geological storage capacity could be significantly improved. [ABSTRACT FROM AUTHOR]

Open ceramic foams are usually constituted of three-dimensional networks with randomly interconnected solid struts and fluid within pores. The heat transport within this material can be understood as the coupling of conduction, convection as well as radiation. The cooperative control of different heat transfer mechanisms is critical to successful design and optimization of components working at high temperatures. An answer to this problem usually requires good knowledge and understanding of the corresponding thermal properties in a wide range of temperatures. In the present paper, an inverse identification method was developed to determine coupled thermal properties from transient thermal measurements at temperatures up to 900 K for full description of conduction/radiation heat transports of foam media with absorbing, emitting, and anisotropic scattering effects. The influence of postulated phase function on the identified equivalent extinction coefficient, scattering albedo, anisotropic scattering factor, and two-phase thermal conductivity was discussed for better understanding of thermal behavior within ceramic foams. The estimated thermal properties under each postulated phase function of the sample at transient temperature profiles were used to calculate equivalent thermal conductivities, which were then compared with the measured results at more than 1000 K. The accordance between them indicated that linear anisotropic scattering phase function demonstrates superiority in description of radiation behavior within Al2O3 ceramic foam. [ABSTRACT FROM AUTHOR]

The effect of external environment on heat and moisture transport and storage properties of the traditional fired clay brick, sand-lime brick and highly perforated ceramic block commonly used in the Czech Republic and on their hygrothermal performance in building envelopes is analyzed by a combination of experimental and computational techniques. The experimental measurements of thermal, hygric and basic physical parameters are carried out in the reference state and after a 3-year exposure of the bricks to real climatic conditions of the city of Prague. The obtained results showed that after 3 years of weathering the porosity of the analyzed bricks increased up to five percentage points which led to an increase in liquid and gaseous moisture transport parameters and a decrease in thermal conductivity. Computational modeling of hygrothermal performance of building envelopes made of the studied bricks was done using both reference and weather-affected data. The simulated results indicated an improvement in the annual energy balances and a decrease in the time-of-wetness functions as a result of the use of data obtained after the 3-year exposure to the environment. The effects of weathering on both heat and moisture transport and storage parameters of the analyzed bricks and on their hygrothermal performance were found significant despite the occurrence of warm winters in the time period of 2012-2015 when the brick specimens were exposed to the environment. [ABSTRACT FROM AUTHOR]

Microstructure and composition are factors determining heat transfer in ZnO ceramic materials, which define the performance of the material after Joule heating, generated by electron transport. In this study, photothermal radiometry was applied to investigate the influence of the sintering temperature, ranging from 800∘C to 1300∘C, by measuring the thermal diffusivity and thermal conductivity at room temperature, of commercial and sol–gel ZnO pellets. Our results show that the values of these thermal properties for both types of ZnO increase when the sintering temperature increases, displaying maximum energy dissipation at 1200∘C. Additionally, the role of the sintering temperature on the optical properties was also analyzed using diffuse reflectance spectroscopy, and from these data the optical band-gap was obtained. [ABSTRACT FROM AUTHOR]