| 1. |
- Bäckström, Gunnar, et al.
(författare)
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Specific heat capacity of solids under pressure from measurements of (dT/dP)s
- 1985
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Ingår i: International journal of thermophysics. - : Plenum Publishing. - 0195-928X .- 1572-9567. ; 6:1, s. 101-105
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Tidskriftsartikel (refereegranskat)abstract
- A procedure is described for calculating specific heat capacity under pressure, cp(T, P), from data for cp(T, 0) and adiabatic (∂T/∂P)s. The main advantage is that (∂T/∂P)s can be readily measured under high-pressure conditions.
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| 2. |
- Fransson, Åke, et al.
(författare)
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Automated differential scanning calorimetry at low temperatures
- 1985
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Ingår i: International journal of thermophysics. - : Plenum Publishing. - 0195-928X .- 1572-9567. ; 6:2, s. 165-175
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Tidskriftsartikel (refereegranskat)abstract
- A Perkin-Elmer DSC-2 scanning calorimeter was operated by means of a PDP-11/34 computer with time-shared scanner and voltmeter. Special attention was paid to the problems of measurement below room temperature down to the low-temperature limit. It was found that Ne, rather than He, should be used as a purge gas, that scans should always be started at a standardized liquid nitrogen level, and that gas flow to the dry box should be stopped during measurements. Results on benzoic acid were then accurate to 0.6 % from 120 to 300 K. The specific heat of antimony was measured in the temperature interval 120–720 K.
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| 3. |
- Fransson, Åke, et al.
(författare)
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Isothermal enthalpy relaxation of glycerol
- 1987
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Ingår i: International journal of thermophysics. - : Plenum Publishing. - 0195-928X .- 1572-9567. ; 8:3, s. 351-362
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Tidskriftsartikel (refereegranskat)abstract
- The isothermal enthalpy relaxation of glycerol has been measured at 13 different annealing times at temperatures of 170, 175, 180, and 185 K. The glasses were formed by linear cooling at 0.667 and 0.083 K·s−1 in a differential scanning calorimeter (DSC). The Williams-Watts relaxation function was fitted to data of enthalpy versus time. A strong temperature dependence was found for the relaxation time. The distribution parameter, β, showed an increase from 0.49 at 170 K to 0.65 at 185 K. We also found indications of an enthalpy dependence in β. Comparison with a theory of volume relaxation showed differences between rates of volume and enthalpy relaxation.
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| 4. |
- Håkansson, Björn, et al.
(författare)
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Thermal conductivity of solid NaF under high pressure
- 1985
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Ingår i: International journal of thermophysics. - : Springer. - 0195-928X .- 1572-9567. ; 6:4, s. 353-365
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity (λ) of solid NaF has been measured over the temperature (T) range 100–350 K and at pressures (P) up to 2.5 GPa, using the transient hot-wire method. Results for λ(T,P) could be described to a good approximation by the Leibfried-Schlömann formula. It was found that the isochoric temperature derivative of the thermal resistivity W (= λ−1) increased systematically with the mass ratio for the B1-type phases of the sodium and potassium halides.
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| 5. |
- Jacobsson, Per, et al.
(författare)
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Thermal conductivity and Lorenz function of zinc under pressure
- 1988
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Ingår i: International journal of thermophysics. - 0195-928X .- 1572-9567. ; 9:4, s. 577-585
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity lambda and the Lorenz function L of polycrystalline zinc have been calculated from measured values of the thermal diffusivity a and the electrical resistivity gamma as functions of pressure P up to 2 GPa at room temperature. The effects of convection in, and freezing of, the pressure transmitting medium are discussed. Both lambda and L increase with increasing P, with pressure coefficients of 8.7×10–2 and 1.5×10–2 GPa–1, respectively. The volume dependence of L is found to be similar to that found for other simple metals. Data are also given for the Seebeck coefficient S as a function of P and for a(T) and lambda(T) between 55 and 300 K.
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| 6. |
- Nilsson, Ove, et al.
(författare)
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Thermal conductivity of B2O3 glass under pressure
- 1985
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Ingår i: International journal of thermophysics. - : Plenum Publishing. - 0195-928X .- 1572-9567. ; 6:3, s. 267-273
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Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity, λ, of vitreous boron trioxide was measured, using a hot-wire procedure, from 170 to 570 K and under pressures of up to 1.7 GPa. The thermal conductivity at room temperature and zero pressure was found to be 0.52 W · m−1 · K−1. The values of the logarithmic pressure derivative, g = d(ln λ)/d(ln ρ), where ρ is the density, were found to be 1.1 for uncompacted glass and 0.7 for glass compacted to 1.2 GPa. The variation of λ with temperature at constant density was approximately linear, with a positive slope of 1.38×10−3W·m−1·K−2.
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| 7. |
- Sigalas, I., et al.
(författare)
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Thermal conductivity and heat capacity of solid NaBr under pressure
- 1985
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Ingår i: International journal of thermophysics. - : Plenum Publishing. - 0195-928X .- 1572-9567. ; 6:2, s. 177-190
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Tidskriftsartikel (refereegranskat)abstract
- Using the transient hot-wire method, measurements were made for solid NaBr of both the thermal conductivity and the heat capacity per unit volume. The measurements were performed in the temperature range 100 to 400 K and at pressures up to 2 GPa. An adiabatic compression technique allowed the determination of the thermal expansivity as a function of pressure at room temperature. The heat capacity did not vary with pressure. Analysis of the thermal conductivity data showed that it can be described adequately by the Leibfried-Schlömann formula. For temperatures up to 400 K only acoustic modes needed to be taken into account. A small contribution of optic modes to the heat transport might be apparent at the highest temperatures.
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