| 1. |
- Alm, Ove, et al.
(författare)
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A multiple coaxial wire for pressure calibration
- 1974
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Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 45:4, s. 594-595
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Tidskriftsartikel (refereegranskat)abstract
- A single wire containing several metals suitable for pressure calibration has been produced by extrusion. Coaxial combinations of Ce-Bi-TI and Ce-Bi-Ba have been prepared by the procedure described.
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| 2. |
- Alm, Ove, et al.
(författare)
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Thermal conductivity of KCl up to 19 kbar
- 1974
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Ingår i: Journal of Physics and Chemistry of Solids. - : Elsevier. - 0022-3697 .- 1879-2553. ; 35:3, s. 421-424
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Tidskriftsartikel (refereegranskat)abstract
- The pressure dependency of the thermal conductivity of KCl has been measured at room temperature up to 19 kbar. The high pressure tool was of the “belt” type and a solid medium was used. The specimen was cylindrical and was heated along its axis. The conductivity was found to increase linearly at a rate of (3·3 ± 0·3) per cent/kbar.
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| 3. |
- Andersson, Per, et al.
(författare)
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Pressure dependence of the thermal conductivity of an epoxy resin
- 1973
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 44:2, s. 705-707
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Tidskriftsartikel (refereegranskat)abstract
- The pressure dependence of the thermal conductivity of Araldite has been determined in a cylindrical geometry at 300 K. The pressure coefficient was found to be independent of the percentage of hardener, the conductivity at 25 kbar being higher by the factor 1.75 ± 0.05 than at atmospheric pressure.
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| 4. |
- Andersson, Per, et al.
(författare)
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Pressure dependence of the thermal conductivity, thermal diffusivity, and specific heat of polyethylene
- 1973
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Ingår i: Journal of Applied Physics. - : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 44:6, s. 2601-2605
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Tidskriftsartikel (refereegranskat)abstract
- The pressure dependence of the specific heat of high‐density polyethylene was determined from simultaneous measurements of thermal conductivity and diffusivity in a cylindrical geometry at 300 K and in the pressure range 0–25 kbar. The thermal conductivity and the diffusivity both increase strongly with pressure, the values at 25 kbar being higher by factors of 2.75 and 2.77, respectively, than those at atmospheric pressure. The specific heat decreases, most strongly so at low pressures, and its value at 25 kbar is 0.80 times that at atmospheric pressure. The thermal conductivity of low‐density polyethylene was determined as a function of pressure. Its value at 25 kbar was found to be 2.19 times that at atmospheric pressure. The difference in conductivity response to pressure between the two varieties is given a simple theoretical interpretation.
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| 5. |
- Andersson, Per, et al.
(författare)
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Specific heat of solids at high pressures from simultaneous measurements of thermal conductivity and diffusivity
- 1972
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Ingår i: High Temperatures-High Pressures. - 0018-1544 .- 1472-3441. ; 4:1, s. 101-109
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Tidskriftsartikel (refereegranskat)abstract
- A method of determining the specific heat of solids at high pressures, from simultaneous measurements of thermal conductivity and diffusivity in a cylindrical geometry, is described. Results are reported for polytetrafluoroethylene (Teflon) in the range 0-30 kbar at 300 K. With increasing pressure both the thermal conductivity and diffusivity increase strongly and approximately linearly, while the specific heat decreases, most strongly at low pressures.
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| 6. |
- Benckert, Lars, et al.
(författare)
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Determination of the photoelastic constants of NaCl, NaF, KCl, and ki by means of brillouin scattering
- 1973
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969 .- 0556-2805. ; 8:12, s. 5888-5893
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Tidskriftsartikel (refereegranskat)abstract
- The photoelastic constants of NaCl, NaF, KCl, and KI have been determined by studying Brillouin scattering at 90° and 180°. The absolute intensities of the Brillouin doublets were obtained by comparing the Brillouin intensity with the intensity scattered by toluene, which has a well-known photoelastic coefficient. The results are NaCl: p11=0.115±0.009, p12=0.161±0.008, p44=−0.011±0.001; NaF:p12=0.123±0.009; KCl:p11=0.233±0.013, p12=0.169±0.008, p44=−0.026±0.002; and KI:p11=0.208±0.012, p12=0.166±0.008, p44=−0.011±0.001.
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| 7. |
- Bohlin, Leif, et al.
(författare)
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A comment on the thermal conductivity of insulating solids at high pressures
- 1974
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Ingår i: Solid State Communications. - : Elsevier. - 0038-1098 .- 1879-2766. ; 14:8, s. 711-714
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Tidskriftsartikel (refereegranskat)abstract
- The effect of pressure on the thermal conductivity has been investigated theoretically fo atomic and polymeric solids. Specific numerical results are given and are compared with experiments for KCl, NaCl and AgCl and for polytetrafluoroethylene and low- and high-density polyethylene. We find the ratio of theory and experiment to be 1.5, 1.9 and 3.0 for the alkali halides, the ratio increases with increasing mass ratio. Corresponding values for the polymers are 1.0, 1.4 and 0.9.
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| 8. |
- Cedergren, Magnus, et al.
(författare)
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Strain gauge measurements of volume changes in polymorphic transitions under pressure
- 1972
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Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 43:4, s. 686-688
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Tidskriftsartikel (refereegranskat)abstract
- A strain gauge wire was wound around a sample of cylindrical shape. One part of the wire was wound around the belly, the other in a plane going through the axis. For a certain choice of the turn ratio and the length-to-diameter ratio the strain could be made proportional to ΔV. From tests performed on Bi, it appears that ΔV / Vo approximately 2 x 10-4 may be detected with the present method. No volume discontinuity corresponding to the phase transition at 43 kilobar reported by Bridgman was observed.
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| 9. |
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| 10. |
- Loriers-Susse, C., et al.
(författare)
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Specific heat measured at high pressures by a pulse method
- 1973
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Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 44:9, s. 1344-1349
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Tidskriftsartikel (refereegranskat)abstract
- The classical electric pulse technique has been adapted to measurements of specific heat at high pressure. A wire specimen is heated by a 100 μsec pulse, stabilized at I = 50 A. The resulting temperature rise is extracted from the voltage drop U over the sample by means of a bridge circuit. The specific heat isobtained from the formula cp = C (T, P) UI/m de/dt, where C (T, P) is a function to be experimentally determined for a given sample, m the mass of the sample, and de/dt the time derivative of the bridge output voltage. A procedure has been developed for in situ corrections of de/dt for heat loss to the medium surrounding the wire. Digital techniques are used for the pulse analysis. The method has been used to ascertain the pressure dependence of cp for Cu up to 100 kilobars at room temperature. The relative change in cp was found to be 2.8 X 10-4/kilobar.
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