scholarly journals Negative linear compressibility

2015 ◽  
Vol 17 (32) ◽  
pp. 20449-20465 ◽  
Author(s):  
Andrew B. Cairns ◽  
Andrew L. Goodwin
Keyword(s):  
Intrinsic Volume ◽  
Uniform Compression ◽  
Linear Compressibility

While all materials reduce their intrinsic volume under hydrostatic (uniform) compression, a select few actually expand along one or more directions during this process of densification.

Negative linear compressibility in nanoporous metal-organic frameworks rationalized by the empty channel structural mechanism

2021 ◽  
Author(s):  
Francisco Colmenero
Keyword(s):  
Crystal Structures ◽  
Metal Organic Frameworks ◽  
Structural Mechanism ◽  
Nanoporous Metal ◽  
Metal Organic ◽  
Linear Compressibility

Cobalt squarate hydroxide (Co3(C4O4)2(OH)2), zinc squarate tetrahydrate (ZnC4O4·4 H2O) and titanium oxalate trioxide dihydrate (Ti2(C2O4)O3·2 H2O) are nanoporous metal-organic frameworks possessing empty channels in their crystal structures. The crystal structures...

Kinetics of pore healing and copper hardening upon uniform compression

2002 ◽  
Vol 47 (8) ◽  
pp. 1058-1060 ◽  
Author(s):  
A. I. Petrov ◽  
M. V. Razuvaeva
Keyword(s):  
Uniform Compression ◽  
Kinetics Of

Secondary regulatory volume increase conferred on Xenopus oocytes by expression of AE2 anion exchanger

1997 ◽  
Vol 272 (1) ◽  
pp. C191-C202 ◽  
Author(s):  
L. Jiang ◽  
M. N. Chernova ◽  
S. L. Alper
Keyword(s):  
Volume Regulation ◽  
Xenopus Oocytes ◽  
Disulfonic Acid ◽  
Functional Coupling ◽  
Intrinsic Volume ◽  
Volume Increase ◽  
Regulatory Volume Increase ◽  
Hypertonic Stimulation ◽  
Shrinkage Prior ◽  
Hypotonic Swelling

Xenopus oocytes lack volume regulation and Cl/anion-exchange (AE) activity but express endogenous Na+/H+ exchange (NHE). We postulated that expression in oocytes of heterologous anion exchangers might allow regulatory volume increase (RVI) via functional coupling with endogenous NHE. Expression of neither erythroid nor kidney isoforms of AE1 conferred any form of RVI. In contrast, although AE2 expression did not confer primary RVI, it did confer on oocytes secondary RVI, with a requirement for hypotonic swelling before hypertonic shrinkage. This secondary RVI required extracellular Cl- and Na+, was blocked by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid and amiloride, was bumetanide insensitive, and was blocked by prevention of intracellular alkalinization, all properties consistent with functional coupling of AE2-mediated Cl-/HCO3- exchange and endogenous NHE. RVI was unaffected by CO2-HCO3- or by partial oocyte Cl- depletion and was unrelated to the rate of oocyte shrinkage. Prior hypotonic swelling did not significantly alter subsequent hypertonic stimulation of AE2-mediated 36Cl influx or efflux. We conclude that heterologous AE2 expression suffices to confer volume regulation on Xenopus oocytes that lack intrinsic volume-regulatory mechanisms.

scholarly journals Dependences of the Omori and Gutenberg–Richter parameters

2019 ◽  
pp. 149-165 ◽  
Author(s):  
V. B. Smirnov ◽  
A. V. Ponomarev ◽  
S. A. Stanchits ◽  
M. G. Potanina ◽  
A. V. Patonin ◽  
...  
Keyword(s):  
Time Delay ◽  
Stress State ◽  
Axial Loading ◽  
B Value ◽  
Exponential Dependence ◽  
Parameter Estimates ◽  
Aftershock Activity ◽  
Uniform Compression ◽  
Effective Strength ◽  
Aftershock Sequences

Laboratory experiments on studying the aftershock regime are carried out with sandstone specimens under different axial loading and uniform compression and constant pore pressure. The aftershock sequences are modeled by the scenario of stepwise increasing axial loading of a specimen with strain control ensuring regular generation of aftershock sequences. The experiments are conducted on intact specimens and on the specimens with preliminarily formed shear macrofractures simulating natural faults. The experiments were conducted with multichannel recording of the acoustic emission (AE) signals which made it possible to locate the AE sources. Several types of the dependence of the acoustic activity relaxation parameters (parameters p and c of the modified Omori law and the Gutenberg–Richter b-value) on the level of acting stresses are revealed. The b-value decreases with the growth of axial stresses at all levels of uniform compression. In the case of fracture on the preexisting fault, the Omori relaxation parameter p increases with the growth of axial stresses whereas parameter c (the time delay before the onset of relaxation) decreases with the growth of axial stresses and increases with the rise of the level of uniform compression. In the case of a fracture of an undamaged specimen, parameter p remains unchanged as the axial stresses grow, whereas parameter c increases slightly. Parameter variations in the case of a complex stress state with both varying deviatoric (differential stresses) and spherical parts (effective pressure) of the stress tensor take on a unified form when expressed in terms of Coulomb stresses. It is hypothesized that the time delay of the aftershock activity relaxation is determined by the kinetics of fracture in accordance with the kinetic concept of strength in solids. This hypothesis is supported by exponential dependence of parameter c on stresses and on the effective strength of the medium revealed in the experiments. Under this hypothesis, the dependences of parameter c on the Coulomb stresses can be unified for different effective strength values with the use of Zhurkov’s formula for durability of materials. The obtained parameter estimates for the dependence of c on strength and stresses suggest that the c value is determined by the difference of the strength and the acting stresses, indicating how far the stress state of the medium is from the critical state corresponding to the ultimate strength.

scholarly journals Evidence of Pressure-Induced Phase Transitions and Negative Linear Compressibility in Formamidinium Manganese-Hypophosphite Hybrid Perovskite

2021 ◽  
Author(s):  
Mirosław Ma̧czka ◽  
Mikołaj Kryś ◽  
Szymon Sobczak ◽  
Daniel Linhares Militão Vasconcelos ◽  
Paulo Tarso Cavalcante Freire ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Hybrid Perovskite ◽  
Linear Compressibility

scholarly journals Deformed and stressed states of materials at the rolling of three layer stacks, dislocation structure of inner layer – nickel foil

2021 ◽  
Vol 66 (3) ◽  
pp. 270-279
Author(s):  
L. I. Hurski
Keyword(s):  
Dislocation Density ◽  
Shear Deformation ◽  
Dislocation Structure ◽  
Three Dimensional ◽  
Nickel Foil ◽  
Dislocation Network ◽  
Uniform Compression ◽  
Degree Of Deformation ◽  
Density Of Dislocations

The deformed and stressed states during rolling of a three-layer stack from various materials with a nickel foil inner layer are considered. The technique of determining the density of dislocations is described. The data about the influence of deformation conditions on the distribution and density of dislocations during rolling of nickel foil in various stacks are presented, including the registration or determination of the dislocation structure of nickel foil before deformation and at various degrees of deformation. It is shown that the mechanical scheme of deformation of the inner layer of the stack, namely, the deformation of the nickel foil by non-uniform compression with shear, has a decisive influence on the development of the dislocation structure and properties. It is established that the dislocation density is determined not only by the degree of deformation, but also by a scheme of the deformed and stressed state of matter, and for the case of shear deformation with increasing degree of deformation the dislocation density increases more rapidly than in the case of tensile strain or compression without shear; the result of shear deformation is a significant refinement of the structure of materials: with increasing degree of plastic deformation of the material a three-dimensional cellular network of dislocation is formed, wherein the borders of cells are formed by tangles of dislocations. With increasing degree of deformation, the density of dislocations at the cell boundaries increases, and the size of the cells decreases; in this case, the areas inside the cells of the dislocation network are always free of dislocations. The obtained results allow recommending the schemes with shear deformation for new promising processes of production of materials with unique properties.

Buckling of a thin annular plate under uniform compression

AIAA Journal ◽  
1971 ◽  
Vol 9 (9) ◽  
pp. 1701-1707 ◽  
Author(s):  
SAURINDRANATH MAJUMDAR
Keyword(s):  
Annular Plate ◽  
Uniform Compression
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