A sample-saving method for heat capacity measurements on powders using relaxation calorimetry

Dachs, Edgar; Benisek, Artur

doi:10.1016/j.cryogenics.2011.04.011

Cited by 61 publications

(47 citation statements)

References 42 publications

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“…Finally, 5 × 5 × 5 supercell calculations give an accuracy of~1% or less in the simulation of the heat capacity and thermodynamic properties in the low-T range. This accuracy is well within the experimental uncertainty of current low-T relaxation calorimetry experiments [70][71][72].…”

Section: Thermodynamic Propertiessupporting

confidence: 63%

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

Belmonte

2017

Minerals

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Ab initio thermodynamic properties, equation of state and phase stability of periclase (MgO, B1-type structure) have been investigated in a broad P-T range (0-160 GPa; 0-3000 K) in order to set a model reference system for phase equilibria simulations under deep Earth conditions. Phonon dispersion calculations performed on large supercells using the finite displacement method and in the framework of quasi-harmonic approximation highlight the performance of the Becke three-parameter Lee-Yang-Parr (B3LYP) hybrid density functional in predicting accurate thermodynamic functions (heat capacity, entropy, thermal expansivity, isothermal bulk modulus) and phase reaction boundaries at high pressure and temperature. A first principles Mie-Grüneisen equation of state based on lattice vibrations directly provides a physically-consistent description of thermal pressure and P-V-T relations without any need to rely on empirical parameters or other phenomenological formalisms that could give spurious anomalies or uncontrolled extrapolations at HP-HT. The post-spinel phase transformation, Mg 2 SiO 4 (ringwoodite) = MgO (periclase) + MgSiO 3 (bridgmanite), is taken as a computational example to illustrate how first principles theory combined with the use of hybrid functionals is able to provide sound results on the Clapeyron slope, density change and P-T location of equilibrium mineral reactions relevant to mantle dynamics.

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Section: Thermodynamic Propertiessupporting

confidence: 63%

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

Belmonte

2017

Minerals

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“…Due to the nanometricthickness of the films, electrons can be scattered by surface [3] and by grain boundaries [4,5], rendering thermal and electrical properties significantly different from those ones of the bulk material. Specific heat and thermal conductivity gives information about electronic, magnetic, and structural properties of materials with thin film geometry; and their determination is required in several fields such as physics, chemistry, materials, and earth sciences [6]. The determination of thermal properties of thin films is an older challenge, and different efforts have been reported in the literature for such an aim [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Specific Heat Determination of Metallic Thin Films at Room Conditions

Lugo

Rejón

Oliva

2015

Journal of Heat Transfer

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A methodology to evaluate the specific heat of metallic thin films at constant pressure and 300 K by means of the heating profile is proposed. Changes on the electrical resistance of metallic films after the application of short electric pulses (20-500 ls) are correlated with changes of temperature of the films. Electric pulses are applied on films by an implemented electronic device. A proposed analytical thermal model predicts the correlation between the duration of the electric pulses and the thermal profiles of the film/substrate systems. The analytical thermal model and the measured thermal profiles results are useful to evaluate the specific heat of films. Following this methodology, Au and Al nanofilms evaporated on glass substrates were analyzed. Results indicate that specific heat values of Au films decrease from (229 6 15) J/kg K to (125 6 8) J/kg K, and for Al films from (1444 6 89) J/kg K to (947 6 53) J/kg K, for film thicknesses from 20 to 200 nm.

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“…Differential scanning calorimetry (DSC) measurements with a Perkin Elmer Diamond DSC in the temperature range 270 K < T < 300 K were performed to check the reproducibility of the PPMS measurements around ambient temperature (Dachs and Benisek, 2011). The powdered sample was put into Perkin Elmer Al pans covered with lids.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

et al. 2012

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The enthalpies of formation of synthetic MgSO 4 $4H 2 O (starkeyite) and MgSO 4 $3H 2 O were obtained by solution calorimetry at T = 298.15 K. The resulting enthalpies of formation from the elements areThe standard entropy of starkeyite was derived from low-temperature heat capacity measurements acquired with a physical property measurement system (PPMS) in the temperature range 5 K < T < 300 K:Additionally, differential scanning calorimetry (DSC) measurements with a Perkin Elmer Diamond DSC in the temperature range 270 K < T < 300 K were performed to check the reproducibility of the PPMS measurements around ambient temperature.The experimental C p data of starkeyite between 229 and 303 K were fitted with a Maier-Kelley polynomial, yielding C p (T) = 107.925 + 0.5532$T -1048894$T -2 . The hydration state of all Mg sulfate hydrates changes in response to local temperature and humidity conditions. Based on recently reported equilibrium relative humidities and the new standard properties described above, the internally consistent thermodynamic database for the MgSO 4 $nH 2 O system was refined by a mathematical programming (MAP) analysis.As can be seen from the resulting phase diagrams, starkeyite is metastable in the entire T-%RH range. Due to kinetic limitations of kieserite formation, metastable occurrence of starkeyite might be possible under martian conditions.

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A sample-saving method for heat capacity measurements on powders using relaxation calorimetry

Cited by 61 publications

References 42 publications

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

Specific Heat Determination of Metallic Thin Films at Room Conditions

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

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A sample-saving method for heat capacity measurements on powders using relaxation calorimetry

Cited by 61 publications

References 42 publications

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

Specific Heat Determination of Metallic Thin Films at Room Conditions

Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO4·4H2O (Starkeyite) and MgSO4·3H2O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates

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Experimentally Determined Standard Thermodynamic Properties of Synthetic MgSO₄·4H₂O (Starkeyite) and MgSO₄·3H₂O: A Revised Internally Consistent Thermodynamic Data Set for Magnesium Sulfate Hydrates