Thermal properties of close-packed Fe up to 400 GPa determined using Hugoniot functions

A quadratic equation for the temperature-independent Grüneisen coefficient γ was derived by a method in which the Walsh-Christian and Mie-Grüneisen equations are combined. Some previously existing ab initio temperature Hugoniots for hexagonal close-packed solid Fe are inaccurate because the constant-volume specific heats on the Hugoniots CVH, which are related uniquely to the solutions of the quadratic equation, have values that are too small. A CVH distribution in the solid phase range was demonstrated to agree approximately with a previous ab initio distribution. In contrast, the corresponding γ distribution was significantly different from the ab initio distribution in the lower pressure region, and the γ distribution in the liquid phase range had a considerably larger gradient than the ab initio distribution. The causes of these disagreements are clarified.Sano Y., Sano T.. Thermal properties of close-packed Fe up to 400 GPa determined using Hugoniot functions. Physical Review B - Condensed Matter and Materials Physics, 69, 14, 144201. https://doi.org/10.1103/PhysRevB.69.144201

Equilibrium thermodynamic theory explicitly including heat transport for evaluation of temperature distributions in steady plane-wave fronts

Previous theories that implicitly included heat transport predicted that temperatures were reduced in proportion to the viscous stresses in the whole region of an overdriven steady wave front in 2024 Al shocked at 80 GPa. Although there was a decrease in temperature caused by the shear stress, the decrease was very slight. A more justifiable theory that includes a heat transport term, the coefficient of which depends on the form and thickness of the effective part of a specific volume wave in the steady wave front, was then developed. The range of appropriate thicknesses of the effective part of the linear and sine forms for shocks up to 80 GPa in 2024 Al were determined. In these ranges, strain increments were sufficiently small and effective temperature rise-times were sufficiently long on the electron-phonon relaxation time scale to justify using equilibrium thermodynamics. In addition, the efficacy of the inside temperature method [Sano and Abe, J. Appl. Phys. 89, 105 (2001)] was illustrated by evaluating heat transport. The inside temperature distribution can be specified if the thickness is measured because the distribution is not influenced to a great extent by the wave form. © 2001 American Institute of Physics.Sano T., Sano Y. Journal of Applied Physics 90(11), 5576-5584 (2001) https://doi.org/10.1063/1.141282

Evaluation of the precursor decay anomaly in single crystal lithium fluoride

To decide whether many dislocations are generated in lithium fluoride (LiF IIIb) and to examine whether the precursor decay anomaly exists, an equation that predicts the dislocation densities on the precursor decay curve without using any modeled dislocation generation rate has been derived. The value of the density of at most about 2.0× 1012 m-2 evaluated on the decay curve in the material IIIb for a projectile velocity of 340 m/s indicates that extremely many dislocations are not generated in the material. This value is not significantly larger than the value of about 1010 m-2 measured at a projectile velocity of 186 m/s. It is inferred from the evaluated value of 2.0× 1012 m-2 that the measured value of 1010 m -2 is not unreasonable and therefore that the precursor decay anomaly does not exist. In addition, it has been revealed that dislocation densities largely increase on the decay curve. © 2009 American Institute of Physics.Yukio Sano and Tomokazu Sano, Journal of Applied Physics 106(2), 023534 (2009) https://doi.org/10.1063/1.315965

Equilibrium thermodynamic theory for the evaluation of temperature distributions in overdriven steady-plane wave fronts

Temperature distributions in overdriven steady wave fronts in solid 2024 Al shocked up to 80 GPa, in which no melting occurred in the wave fronts, were evaluated using the equilibrium thermodynamic theory. The effective strain increments were sufficiently small and the effective temperature rise times were sufficiently long with respect to electron-phonon relaxation times to justify using equilibrium thermodynamics. In addition, the sufficiently large viscous-stress components supported the efficacy of the thermodynamic theory. The same is true of shocks up to 250 GPa in solid Pt and 230 GPa in solid Fe. Furthermore, the influence of viscous stress was examined by evaluating the temperature distributions for inviscid 2024 Al, Pt, and Fe solids using the equations for temperature derived from the Mie-Grüneisen equation. Finally, we demonstrate that there might be a solid-liquid-solid Hugoniot between the solid and liquid-solid Hugoniots for Fe and estimate the solid-liquid-solid and liquid-solid Hugoniots. © 2001 American Institute of Physics.Sano T., Sano Y. Journal of Applied Physics 90(8), 3754 (2001) https://doi.org/10.1063/1.139727

Dynamic yielding in lithium fluoride and aluminum

At a time immediately after shock loading, a kink (a weak discontinuity or a discontinuity in slope) occurs at a position in an unsteady portion in a smooth plane wave front in a lithium fluoride single crystal (material III b) or in 1060-0 aluminum due to the instability of the wave front. After the occurrence of the kink, a zone is produced and broadened with time between a near steady precursor ahead of the kink and a plastic wave behind it in a weak-discontinuity plane wave by the difference in the propagation velocity between them. Stress relaxes in the zone, which is called a follower, and the precursor decay takes place due to the stress relaxation. During the decay process, the large increase in plastic flow occurs in the vicinity of the leading edge of the follower, causes yielding at the leading edge, and stabilizes the weak-discontinuity wave. The stress-strain (σ-ε) history caused by the follower rotates clockwise with time around the yield point. The rotation yields different σ-ε histories behind the point and therefore different types of the dynamic σ-ε relation. Dynamic yield phenomena are illustrated by showing the schematic diagrams of three different types of the dynamic σ-ε relation, which are caused by weak-discontinuity plane waves composed of a precursor C, a follower (i) C, (ii) I or II, or (iii) R′ or Rb, and a plastic wave C behind the follower. Here C is the contraction (compression) wave, I and II are the degenerate contraction waves I and II, R′ is the subrarefaction wave, and Rb is the rarefaction wave. © 2010 American Institute of Physics.Yukio Sano and Tomokazu Sano, Journal of Applied Physics 107(4), 043506 (2010) https://doi.org/10.1063/1.327550

Electronic and ionic contributions to the constant-volume specific heat of carbon tetrachloride shocked at pressures up to 23 GPa

For carbon tetrachloride, a temperature Hugoniot at 7-23 GPa and a distribution of the constant-volume specific heat on the Hugoniot C V(T) at 1057-3275 K are simultaneously estimated from the Walsh-Christian (WC) equation such that the Hugoniot fits well to the existing measured data. The estimated CV(T) distribution reveals the significance of the contribution of electrons and ions to the specific heat. That is, in contrast to the almost uniform distribution of the specific heat predicted from the Debye equation, the CV(T) distribution increases significantly with an increase in the Hugoniot temperature due to thermal excitation of electrons at 1057-1500 K (7-10.1 GPa), additional activation of the dimerization reaction at 1500-2350 K (10.1-16 GPa), and also additional activation of the polymerization reaction at 2350-3275 K (16-23 GPa). As an example, evidence is presented that carbon tetrachloride is a semiconductor at 1500 K. The CV(T) distribution in each temperature range is formulated and a temperature Hugoniot is reevaluated from the WC equation using the specific heat equations formulated. It is confirmed by a good fit of the reevaluated Hugoniot to the existing measured data that the specific heat equations express the CV(T) distribution appropriately. © 2010 American Institute of Physics.Yukio Sano, Tomokazu Sano, and Shinichi Nagata, Journal of Applied Physics 107(3), 033507 (2010) https://doi.org/10.1063/1.329496

Acetaldehyde Removal from Indoor Air through Chemical Absorption Using L-Cysteine

The irreversible removal of acetaldehyde from indoor air via a chemical reaction with amino acids was investigated. To compare effectiveness, five types of amino acid (glycine, l-lysine, l-methionine, l-cysteine, and l-cystine) were used as the reactants. First, acetaldehyde-laden air was introduced into aqueous solutions of each amino acid and the removal abilities were compared. Among the five amino acids, l-cysteine solution showed much higher removal efficiency, while the other amino acids solutions didn’t show any significant differences from the removal efficiency of water used as a control. Next, as a test of the removal abilities of acetaldehyde by semi-solid l-cysteine, a gel containing l-cysteine solution was put in a fluororesin bag filled with acetaldehyde gas, and the change of acetaldehyde concentration was measured. The l-cysteine-containing gel removed 80% of the acetaldehyde in the air within 24 hours. The removal ability likely depended on the unique reaction whereby acetaldehyde and l-cysteine rapidly produce 2-methylthiazolidine-4-carboxylic acid. These results suggested that the reaction between acetaldehyde and l-cysteine has possibilities for irreversibly removing toxic acetaldehyde from indoor air

Increased IP-10 production by blood–nerve barrier in multifocal acquired demyelinating sensory and motor neuropathy and multifocal motor neuropathy

Objective Dysfunction of the blood–nerve barrier (BNB) plays important roles in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). The aim of the present study was to identify the candidate cytokines/chemokines that cause the breakdown of the BNB using sera from patients with CIDP and MMN. Methods We determined the levels of 27 cytokines and chemokines in human peripheral nerve microvascular endothelial cells (PnMECs) after exposure to sera obtained from patients with CIDP variants (typical CIDP and multifocal acquired demyelinating sensory and motor neuropathy [MADSAM]), MMN and amyotrophic lateral sclerosis (ALS), and healthy controls (HC), using a multiplexed fluorescent bead-based immunoassay system. Results The induced protein (IP)10 level in the cells in both the MADSAM and MMN groups was markedly increased in comparison with the typical CIDP, ALS and HC groups. The other cytokines, including granulocyte colony-stimulating factor, vascular endothelial growth factor (VEGF) and interleukin-7, were also significantly upregulated in the MADSAM group. The increase of IP-10 produced by PnMECs was correlated with the presence of conduction block in both the MADSAM and MMN groups. Conclusion The autocrine secretion of IP-10 induced by patient sera in PnMECs was markedly upregulated in both the MADSAM and MMN groups. The overproduction of IP-10 by PnMECs leads to the focal breakdown of the BNB and may help to mediate the transfer of pathogenic T cells across the BNB, thereby resulting in the appearance of conduction block in electrophysiological studies of patients with MADSAM and MMN