Studies of Critical Phenomena in Carbon Dioxide contained in Vertical Tubes.

Lorentzen, Hans Ludvig; Heedman, Per Axel; Pesola, Rainer; Virtanen, Artturi I.; Sørensen, Nils Andreas

doi:10.3891/acta.chem.scand.07-1335

Cited by 52 publications

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“…There is thus a slight but hardly significant tendency for 0 to decrease as T c is approached. A similar effect has been observed 11 in 4 He. It should be noted that the above fitting procedure evaluates the constants in Eq.…”

supporting

confidence: 86%

“…6 where p c is the critical density and T c the critical temperature, 1 Recently, there has been considerable interest in determining the parameters in this relation with improved precision. 2 For "ordinary" fluids such as xenon 3 and carbon dioxide, 4 0 is found to be close to f; however, for the light elements 4 He, 3 He, and H 2 , larger values have been reported. 5 " 7 This observation prompted the suggestion 8 " 10 that the value of j3 might be affected by quantum devi-Orthobaric densities were determined by measuring the dielectric constant of the fluid (liquid or vapor) contained between a single horizontal pair of capacitor plates, assuming that the Clausius-Mosotti relation holds with constant polarizability (which we take to be 0.123 00).…”

mentioning

confidence: 93%

“…15 During the current measurements temperatures were simultaneously determined from the above 4 He vapor-pressure thermometer and from the measured vapor pressure of the 3 He, using the T 58 scale 16 and the 3 He T 62 scale, 17 respectively. The 4 He temperature averaged about 2xl0~4 o K higher. This small difference may be due in part to the hydrostatic head of 3 He in a short (^5-cm) section of fill tube below the vacuum jacket, or to discrepancies between the vapor pressure scales.…”

mentioning

confidence: 94%

“…If a correction for the 4 He impurity in our sample is made by assuming the critical temperature to vary linearly with concentration between the values characteristic of pure 3 He and pure 4 He, T c would be lowered by 0.000 66°K to 3.3088°K. Approximately the same amount of impurity was present in the experiments of Sydoriak and Sherman 19 on which the 1962 3 He temperature scale is based, and a similar correction was made.…”

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confidence: 99%

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Orthobaric Density ofHe3in the Critical Region

Zimmerman

Chase

1967

Phys. Rev. Lett.

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also measured the (limiting) thickness of the shock as a function of plasma density. At pressures p ^ 10~2 mm Hg, with *U^ and >^n the i-i and i-n collision mean free paths, respectively, we expect I to be determined entirely by >^-, i.e., Z~ 1/n. That this is the case can be seen from the data of Fig. 3(b), where I is shown as a function of the plasma density n ahead of the shock for a He gas pressure of ~10~2 mm Hg.In conclusion, our results indicate that in plasmas of comparable ion and electron temperatures Landau damping prevents the formation of a shock wave by overcoming the sharpening effect of the nonlinearities. Landau damp ing can, however, be "switched-off" by increasThe coexistence curve of 3 He has been measured by a dielectric constant technique in the neighborhood of the critical point. The parameters in the relation | (p-p c )/p c | =A[{T C~T )/T C ]P are found to be p c = 0.04134 g/cm 3 , T C =3.3095°K, A = 1.323, and /3 = 0.362. Our value of T c is some 14 mdeg lower than previous measurements indicate, and our value of j3 more nearly in agreement with values characteristic of other fluids than was previously found.ations from the law of corresponding states. Recent work by Roach and Douglass 11 casts doubt on this suggestion. They find that for 4 He, 0 = 0.352±0.003, which is to be compared with an earlier estimate 9 of 0.46. Such quantum deviations, if present, should be largest of all for 3 He. We have accordingly measured its coexistence curve by means of a dielectric constant technique, using an improved version of an apparatus previously described, 12 and find j3 = 0.362± 0.001. Any such deviations are therefore substantially smaller than earlier data suggested. We also find that T c is some 14 mdeg lower than previously reported. This correction is largely responsible for our smaller value of /3, since far from the critical point our data agree well with the results of others. 6 ' 13 151 ing T e /T^ from unity to about 10 or so. Further details on our measurements will be presented at a later date.Finally, it should be noted that our results may be relevant to shock formation in interplanetary plasmas.

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confidence: 86%

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confidence: 93%

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confidence: 94%

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confidence: 99%

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Orthobaric Density ofHe3in the Critical Region

Zimmerman

Chase

1967

Phys. Rev. Lett.

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“…(16) It can be seen that the diffusion resulting from the electric field in the three collisional regimes given by Eqs. (9), (13), and (16) join smoothly at the appropriate values of mean free path.…”

Section: P E = Qttp(0)/b E 2 (A)~lmentioning

confidence: 98%

Effect of Longitudinal Electric Field on Toroidal Diffusion

et al. 1970

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Phase transitions of hydrogen in metals due to elastic interaction

Alefeld

1972

Ber Bunsenges Phys Chem

161

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Hydrogen in metals can be considered as an example for a lattice gas with phase transitions.In the first part a phenomenological discussion of the phase diagrams of hydrogen in Pd, Nb, Ta and V will be given. It will be shown that these phase diagrams show topologically great similarity to those which hold for the phase transitions gas‐liquid‐solid of a one component system.In the second part the elastic dipole dipole interaction will be discussed. This interaction is considered to be the predominant part of the attractive interaction responsible for the “gas‐liquid” transition. Three experimental methods to measure the mean interaction energy of the lattice gas will be discussed. Experimental results for the mean interaction energy will be compared with theoretical predictions. Arguments are presented that the critical temperature for the gas liquid transition should be strongly decreased by embedding the sample into material with elastic coefficients stiffer than those of the sample.

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Studies of Critical Phenomena in Carbon Dioxide contained in Vertical Tubes.

Cited by 52 publications

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Orthobaric Density ofHe3in the Critical Region

Orthobaric Density ofHe3in the Critical Region

Effect of Longitudinal Electric Field on Toroidal Diffusion

Phase transitions of hydrogen in metals due to elastic interaction

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