Supercritical Fluid Gaseous and Liquid States: A Review of Experimental Results

We review the experimental evidence, from both historic and modern literature of thermodynamic properties, for the non-existence of a critical-point singularity on Gibbs density surface, for the existence of a critical density hiatus line between 2-phase coexistence, for a supercritical mesophase with the colloidal characteristics of a one-component 2-state phase, and for the percolation loci that bound the existence of gaseous and liquid states. An absence of any critical-point singularity is supported by an overwhelming body of experimental evidence dating back to the original pressure-volume-temperature (p-V-T) equation-of-state measurements of CO2 by Andrews in 1863, and extending to the present NIST-2019 Thermo-physical Properties data bank of more than 200 fluids. Historic heat capacity measurements in the 1960s that gave rise to the concept of “universality” are revisited. The only experimental evidence cited by the original protagonists of the van der Waals hypothesis, and universality theorists, is a misinterpretation of the isochoric heat capacity Cv. We conclude that the body of extensive scientific experimental evidence has never supported the Andrews–van der Waals theory of continuity of liquid and gas, or the existence of a singular critical point with universal scaling properties. All available thermodynamic experimental data, including modern computer experiments, are compatible with a critical divide at Tc, defined by the intersection of two percolation loci at gaseous and liquid phase bounds, and the existence of a colloid-like supercritical mesophase comprising both gaseous and liquid states.

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Experimental evidence for the remarkable behavior of the partial molar heat capacity at infinite dilution of aqueous electrolytes at the critical point

The Journal of Physical Chemistry ◽

10.1021/j100222a023 ◽

1982 ◽

Vol 86 (25) ◽

pp. 4948-4951 ◽

Cited By ~ 29

Author(s):

Jeffrey A. Gates ◽

Robert H. Wood ◽

Jacques R. Quint

Keyword(s):

Heat Capacity ◽

Experimental Evidence ◽

Critical Point ◽

Infinite Dilution ◽

Molar Heat Capacity ◽

Aqueous Electrolytes ◽

Partial Molar Heat Capacity

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Thermodynamic Functions at Isobaric Process of van der Waals Gases

Zeitschrift für Naturforschung A ◽

10.1515/zna-2000-11-1202 ◽

2000 ◽

Vol 55 (11-12) ◽

pp. 851-855

Author(s):

Akira Matsumoto

Keyword(s):

Heat Capacity ◽

Free Energy ◽

Critical Point ◽

Thermodynamic Functions ◽

Isothermal Compressibility ◽

Van Der Waals ◽

Thermal Expansivity ◽

Van Der Waals Equation ◽

Reduced Temperature ◽

Isobaric Process

Abstract The thermodynamic functions for the van der Waals equation are investigated at isobaric process. The Gibbs free energy is expressed as the sum of the Helmholtz free energy and PV, and the volume in this case is described as the implicit function of the cubic equation for V in the van der Waals equation. Furthermore, the Gibbs free energy is given as a function of the reduced temperature, pressure and volume, introducing a reduced equation of state. Volume, enthalpy, entropy, heat capacity, thermal expansivity, and isothermal compressibility are given as functions of the reduced temperature, pressure and volume, respectively. Some thermodynamic quantities are calculated numerically and drawn graphically. The heat capacity, thermal expansivity, and isothermal compressibility diverge to infinity at the critical point. This suggests that a second-order phase transition may occur at the critical point.

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Receptions of the Past: Commemoration, Racism, Desire

Somatechnics ◽

10.3366/soma.2017.0223 ◽

2017 ◽

Vol 7 (2) ◽

pp. 288-303

Author(s):

Michael Connors Jackman

Keyword(s):

Critical Point ◽

Social Relations ◽

White Privilege ◽

Body Politic ◽

The Body ◽

Race And Racism ◽

Lesbian And Gay ◽

The Past ◽

History Of

This article investigates the ways in which the work of The Body Politic (TBP), the first major lesbian and gay newspaper in Canada, comes to be commemorated in queer publics and how it figures in the memories of those who were involved in producing the paper. In revisiting a critical point in the history of TBP from 1985 when controversy erupted over race and racism within the editorial collective, this discussion considers the role of memory in the reproduction of whiteness and in the rupture of standard narratives about the past. As the controversy continues to haunt contemporary queer activism in Canada, the productive work of memory must be considered an essential aspect of how, when and for what reasons the work of TBP comes to be commemorated. By revisiting the events of 1985 and by sifting through interviews with individuals who contributed to the work of TBP, this article complicates the narrative of TBP as a bluntly racist endeavour whilst questioning the white privilege and racially-charged demands that undergird its commemoration. The work of producing and preserving queer history is a vital means of challenging the intentional and strategic erasure of queer existence, but those who engage in such efforts must remain attentive to the unequal terrain of social relations within which remembering forms its objects.

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Computational Insights Into Air-Side Flow and Heat Transfer in Compact Heat Exchangers

Heat Transfer: Volume 2 ◽

10.1115/ht2005-72846 ◽

2005 ◽

Author(s):

D. K. Tafti

Keyword(s):

Heat Transfer ◽

Heat Capacity ◽

Heat Exchangers ◽

Three Dimensional ◽

Computer Experiments ◽

Transfer Coefficients ◽

Substantial Impact ◽

Compact Heat Exchangers ◽

Thermal Phenomena ◽

Side Flow

The paper describes two- and three-dimensional computer simulations which are used to study fundamental flow and thermal phenomena in multilouvered fins used for air-side heat transfer enhancement in compact heat exchangers. Results pertaining to flow transition, thermal wake interference, and fintube junction effects are presented. It is shown that a Reynolds number based on flow path rather than louver pitch is more appropriate in defining the onset of transition, and characteristic frequencies in the louver bank scale better with a global length scale such as fin pitch than with louver pitch or thickness. With the aid of computer experiments, the effect of thermal wakes is quantified on the heat capacity of the fin as well as the heat transfer coefficient, and it is established that experiments which neglect accounting for thermal wakes can introduce large errors in the measurement of heat transfer coefficients. Further, it is shown that the geometry of the louver in the vicinity of the tube surface has a large effect on tube heat transfer and can have a substantial impact on the overall heat capacity.

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Finite-size transitions in complex membranes

10.1101/2020.11.05.370189 ◽

2020 ◽

Author(s):

M. Girard ◽

T. Bereau

Keyword(s):

Experimental Evidence ◽

Critical Point ◽

Finite Size ◽

Underlying Mechanism ◽

Large Temperature ◽

Strong Argument ◽

Biological Regulation ◽

Critical Manifold ◽

Critical Composition ◽

Dynamics Simulations

ABSTRACTThe lipid raft hypothesis postulates that cell membranes possess some degree of lateral organization. The last decade has seen a large amount of experimental evidence for rafts. Yet, the underlying mechanism remains elusive. One hypothesis that supports rafts relies on the membrane to lie near a critical point. While supported by experimental evidence, the role of regulation is unclear. Using both a lattice model and molecular dynamics simulations, we show that lipid regulation of a many-component membrane can lead to critical behavior over a large temperature range. Across this range, the membrane displays a critical composition due to finite-size effects. This mechanism provides a rationale as to how cells tune their composition without the need for specific sensing mechanisms. It is robust and reproduces important experimentally verified biological trends: membrane-demixing temperature closely follows cell growth temperature, and the composition evolves along a critical manifold. The simplicity of the mechanism provides a strong argument in favor of the critical membrane hypothesis.SIGNIFICANCEWe show that biological regulation of a large amount of phospholipids in membranes naturally leads to a critical composition for finite-size systems. This suggests that regulating a system near a critical point is trivial for cells. These effects vanish logarithmically and therefore can be present in micron-sized systems.

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The reduced dynamic (absolute) and kinematic viscosities of the metals—mercury, sodium and potassium—over their entire liquid range, i.e., from the melting point to the critical point, and a comparison with van der Waals' substances

Journal of Inorganic and Nuclear Chemistry ◽

10.1016/0022-1902(65)80407-9 ◽

1965 ◽

Vol 27 (5) ◽

pp. 979-987 ◽

Cited By ~ 3

Author(s):

A.V. Grosse

Keyword(s):

Melting Point ◽

Critical Point ◽

Van Der Waals ◽

Sodium And Potassium ◽

Reduced Dynamic

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Critical Point of Metals from the van der Waals Model

Physical Review A ◽

10.1103/physreva.3.364 ◽

1971 ◽

Vol 3 (1) ◽

pp. 364-371 ◽

Cited By ~ 126

Author(s):

David A. Young ◽

Berni J. Alder

Keyword(s):

Critical Point ◽

Van Der Waals ◽

Van Der Waals Model

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Some notes on the relationship of plant viruses with vector and non-vector insects

Parasitology ◽

10.1017/s003118200002429x ◽

1941 ◽

Vol 33 (1) ◽

pp. 110-116 ◽

Cited By ~ 14

Author(s):

Kenneth M. Smith

Keyword(s):

Sugar Beet ◽

Experimental Evidence ◽

Plant Viruses ◽

Artificial Feeding ◽

The Body ◽

The Other ◽

Insect Vector ◽

Feeding Methods ◽

Relationship Of ◽

The Relationship

Extracts of caterpillars and other insects are shown to inhibit the infective power of tobacco mosaic and tobacco necrosis viruses. The inhibitor is not sedimented after spinning for 2½ hr. at 30,000 r.p.m. Experiments with non-vector insects such as caterpillars have shown that the virus of sugar-beet curly-top, of tobacco ringspot and other viruses, are destroyed within the body of the insect. On the other hand, tobacco mosaic virus passes through the body of the caterpillar unchanged though greatly reduced in concentration. By the use of the specific insect vector and artificial feeding methods it was possible to recover the virus of curly-top 24 hr. after it had been injected into the blood of the caterpillar but the viruses of tobacco mosaic and tobacco necrosis could not be so recovered. Experimental evidence is given to show that the virus of beet curly-top is present in the saliva of viruliferous insects.

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