scholarly journals Formation, preservation and extinction of high-pressure minerals in meteorites: temperature effects in shock metamorphism and shock classification

2021 ◽  
Author(s):  
Jinping Hu ◽  
Thomas Sharp
Keyword(s):  
High Pressure ◽  
Shock Pressure ◽  
Shock Metamorphism ◽  
Large Temperature ◽  
Moderate Pressure ◽  
Ambient Conditions ◽  
Melting Temperatures ◽  
High Shock ◽  
Deformation Features ◽  
Post Shock

Abstract The goal of classifying shock metamorphic features in meteorites is to estimate the corresponding shock pressure conditions. However, the temperature variability of shock metamorphism is equally important and can result in a diverse and heterogeneous set of shock features in samples with a common overall shock pressure. In particular, high-pressure (HP) minerals, which were previously used as a solid indicator of high shock pressure in meteorites, require complex pressure-temperature-time (P-T-t) histories to form and survive. First, parts of the sample must be heated to the melting temperatures, at high pressure, to enable rapid formation of HP minerals before pressure release. Second, the HP minerals must be rapidly cooled to below a critical temperature, before the pressure returns to ambient conditions, to avoid retrograde transformation to their low-pressure polymorphs. These two constraints require the sample to contain large temperature heterogeneities, e.g. melt veins in a cooler groundmass, during shock. In this study, we calculated shock temperatures and possible P-T paths of chondritic and differentiated mafic rocks for various shock pressures. These P-T conditions and paths, combined with observations from shocked meteorites, are used to constrain shock conditions and P-T-t histories of HP-mineral bearing samples. The need for rapid thermal quench of HP phases requires a relatively low bulk-shock temperature and therefore moderate shock pressures below ~ 30 GPa, which matches the stabilities of these HP minerals. The low-temperature moderate-pressure host rock generally shows moderate shock-deformation features consistent with S4 and, less commonly, S5 shock stages. Shock pressures in excess of 50 GPa in meteorites result in melt breccias with high overall post-shock temperatures that anneal out HP-mineral signatures. The presence of ringwoodite, which is commonly considered an indicator of the S6 shock stage, is inconsistent with pressures in excess of 30 GPa and does not represent shock conditions different from S4 shock conditions. Indeed, ringwoodite and coexisting HP minerals should be considered as robust evidence for moderate shock pressures (S4) rather than extreme shock (S6) near whole-rock melting.

scholarly journals Formation, preservation and extinction of high-pressure minerals in meteorites: temperature effects in shock metamorphism and shock classification

2022 ◽  
Vol 9 (1) ◽  
Author(s):  
Jinping Hu ◽  
Thomas G. Sharp
Keyword(s):  
High Pressure ◽  
Shock Pressure ◽  
Shock Metamorphism ◽  
Large Temperature ◽  
Moderate Pressure ◽  
Ambient Conditions ◽  
Melting Temperatures ◽  
High Shock ◽  
Deformation Features ◽  
Post Shock

AbstractThe goal of classifying shock metamorphic features in meteorites is to estimate the corresponding shock pressure conditions. However, the temperature variability of shock metamorphism is equally important and can result in a diverse and heterogeneous set of shock features in samples with a common overall shock pressure. In particular, high-pressure (HP) minerals, which were previously used as a solid indicator of high shock pressure in meteorites, require complex pressure–temperature–time (P–T–t) histories to form and survive. First, parts of the sample must be heated to melting temperatures, at high pressure, to enable rapid formation of HP minerals before pressure release. Second, the HP minerals must be rapidly cooled to below a critical temperature, before the pressure returns to ambient conditions, to avoid retrograde transformation to their low-pressure polymorphs. These two constraints require the sample to contain large temperature heterogeneities, e.g. melt veins in a cooler groundmass, during shock. In this study, we calculated shock temperatures and possible P–T paths of chondritic and differentiated mafic–ultramafic rocks for various shock pressures. These P–T conditions and paths, combined with observations from shocked meteorites, are used to constrain shock conditions and P–T–t histories of HP-mineral bearing samples. The need for rapid thermal quench of HP phases requires a relatively low bulk-shock temperature and therefore moderate shock pressures below ~ 30 GPa, which matches the stabilities of these HP minerals. The low-temperature moderate-pressure host rock generally shows moderate shock-deformation features consistent with S4 and, less commonly, S5 shock stages. Shock pressures in excess of 50 GPa in meteorites result in melt breccias with high overall post-shock temperatures that anneal out HP-mineral signatures. The presence of ringwoodite, which is commonly considered an indicator of the S6 shock stage, is inconsistent with pressures in excess of 30 GPa and does not represent shock conditions different from S4 shock conditions. Indeed, ringwoodite and coexisting HP minerals should be considered as robust evidence for moderate shock pressures (S4) rather than extreme shock (S6) near whole-rock melting.

Hydrogen bonding in liquid methanol at ambient conditions and at high pressure

2000 ◽  
Vol 98 (3) ◽  
pp. 125-134 ◽  
Author(s):  
T. Weitkamp, J. Neuefeind, H. E. Fisch
Keyword(s):  
High Pressure ◽  
Hydrogen Bonding ◽  
Ambient Conditions

scholarly journals Formation of the -N(NO)N(NO)- polymer at high pressure and stabilization at ambient conditions

2013 ◽  
Vol 110 (14) ◽  
pp. 5321-5325 ◽  
Author(s):  
H. Xiao ◽  
Q. An ◽  
W. A. Goddard ◽  
W.-G. Liu ◽  
S. V. Zybin
Keyword(s):  
High Pressure ◽  
Ambient Conditions

Deformation of polyiodides in Cs2I8 crystals at high pressure

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Tomasz Poreba ◽  
Gaston Garbarino ◽  
Davide Comboni ◽  
Mohamed Mezouar
Keyword(s):  
High Pressure ◽  
Electron Transfer ◽  
Bulk Modulus ◽  
Electronic Properties ◽  
Supramolecular Architecture ◽  
Ambient Conditions ◽  
Electron Transfer Mechanism ◽  
Covalently Bonded ◽  
Potential Sources ◽  
High Bulk

Dicaesium octaiodide is composed of layers of zigzag polyiodide units (I8 2−) intercalated with caesium cations. Each I8 2− unit is built of two triiodides bridged with one diiodine molecules. This system was subjected to compression up to 5.9 GPa under hydrostatic conditions. Pressure alters the supramolecular architecture around I8 2−, leading to bending of the triiodide units away from their energetically preferred geometry (D ∞h). Short I2...I3 − contacts compress significantly, reaching lengths typical for the covalently bonded polyiodides. Unlike in reported structures at ambient conditions, pressure-induced catenation proceeds without symmetrization of the polyiodides, pointing to a different electron-transfer mechanism. The structure is shown to be half as compressible [B0 = 12.9 (4) GPa] than the similar CsI3 structure. The high bulk modulus is associated with higher I—I connectivity and a more compact cationic net, than in CsI3. The small discontinuity in the compressibility trend around 3 GPa suggests formation of more covalent I—I bonds. The potential sources of this discontinuity and its implication on the electronic properties of Cs2I8 are discussed.

Gel-setting and Gel-melting Temperatures of Aqueous Gelatin Solutions under High Pressure Measured by a Hot-wire Method

1996 ◽  
Vol 60 (8) ◽  
pp. 1349-1350 ◽  
Author(s):  
Keiko Shimada ◽  
Yoshio Sakai ◽  
Kazuyuki Nagamatsu ◽  
Tomoshige Hori ◽  
Rikimaru Hayashi
Keyword(s):  
High Pressure ◽  
Hot Wire ◽  
Melting Temperatures ◽  
Wire Method

DFT study of pressure effects in molecular crystal 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo-[5.5.0.05,903,11]-dodecane

2014 ◽  
Vol 92 (7) ◽  
pp. 616-624 ◽  
Author(s):  
Zhichao Liu ◽  
Qiong Wu ◽  
Weihua Zhu ◽  
Heming Xiao
Keyword(s):  
High Pressure ◽  
Energy Loss ◽  
Loss Function ◽  
Density Functional ◽  
Pressure Range ◽  
Blue Shift ◽  
Pressure Effects ◽  
Ambient Conditions ◽  
Energy Loss Function ◽  
Electron Transitions

Density functional theory was used to study the structural, electronic, and optical properties of crystalline 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazatetracyclo-[5.5.0.05,903,11]-dodecane (TEX) under hydrostatic pressure. The results indicate that there is a displacive transition in TEX under compression that has never been found in experiments. As the pressure increases, the band gap gradually decreases but presents an abnormal increase at 61 GPa, called the structural transition; moreover, the gap reduction is more pronounced in the low-pressure range compared with the high-pressure range. An analysis of density of states shows that the electronic delocalization in TEX is enhanced gradually under the influence of pressure. The peaks of the imaginary parts of the dielectric functions, energy-loss function, and reflectivity may come mainly from the electron transitions between the oxygen 2p and nitrogen 2p states. The electron energy-loss function presents a blue shift under compression. TEX has relatively higher optical activity at high pressure than at ambient conditions.

High-pressure new phase of AgN3

2021 ◽  
pp. 2150386
Author(s):  
Shifeng Niu ◽  
Ran Liu ◽  
Xuhan Shi ◽  
Zhen Yao ◽  
Bingbing Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
Energy Density ◽  
Density Functional ◽  
High Energy ◽  
High Energy Density ◽  
Detonation Properties ◽  
Ambient Conditions ◽  
Structure Search ◽  
Enthalpy Difference ◽  
High Energy Density Material

The structural evolutionary behaviors of AgN3 have been studied by using the particle swarm optimization structure search method combined with the density functional theory. One stable high-pressure metal polymeric phase with the [Formula: see text] space group is suggested. The enthalpy difference analysis indicates that the Ibam-AgN3 phase will transfer to the I4/mcm-AgN3 phase at 4.7 GPa and then to the [Formula: see text]-AgN3 phase at 24 GPa. The [Formula: see text]-AgN3 structure is composed of armchair–antiarmchair N-chain, in which all the N atoms are sp2 hybridization. The inherent stability of the armchair–antiarmchair chain and the anion–cation interaction between the N-chain and Ag atom induce a high stability of the [Formula: see text]-AgN3 phase, which can be captured at ambient conditions and hold its stable structure up to 1400 K. The exhibited high energy density (1.88 KJ/g) and prominent detonation properties ([Formula: see text] Km/s; [Formula: see text] GPa) of the [Formula: see text]-AgN3 phase make it a potentially high energy density material.

Training response to 8 weeks of blood flow restricted training is not improved by preferentially altering tissue hypoxia or lactate accumulation when training to repetition failure

2021 ◽  
Author(s):  
William Neil Morley ◽  
Shane Ferth ◽  
Mathew Ian Bergens Debenham ◽  
Matthew Boston ◽  
Geoffrey Alonzo Power ◽  
...  
Keyword(s):  
High Pressure ◽  
Blood Flow ◽  
Resistance Training ◽  
Blood Lactate ◽  
Blood Flow Restriction ◽  
Moderate Pressure ◽  
Muscular Endurance ◽  
Occlusion Pressure ◽  
Flow Restriction ◽  
Traditional Resistance Training

Despite compelling muscular structure and function changes resulting from blood flow restricted (BFR) resistance training, mechanisms of action remain poorly characterized. Alterations in tissue O2 saturation (TSI%) and metabolites are potential drivers of observed changes, but their relationships with degree of occlusion pressure are unclear. We examined local TSI% and blood lactate (BL) concentration during BFR training to failure using different occlusion pressures on strength, hypertrophy, and muscular endurance over an 8-week training period. Twenty participants (11M:9F) trained 3/wk for 8wk using high pressure (100% resting limb occlusion pressure, LOP, 20%1RM), moderate pressure (50% LOP, 20%1RM), or traditional resistance training (70%1RM). Strength, size, and muscular endurance were measured pre/post training. TSI% and BL were quantified during a training session. Despite overall increases, no group preferentially increased strength, hypertrophy, or muscular endurance (p>0.05). Neither TSI% nor BL concentration differed between groups (p>0.05). Moderate pressure resulted in greater accumulated deoxygenation stress (TSI%*time) (-6352±3081, -3939±1835, -2532±1349 au for moderate pressure, high pressure, and TRT, p=0.018). We demonstrate that BFR training to task-failure elicits similar strength, hypertrophy, and muscular endurance changes to traditional resistance training. Further, varied occlusion pressure does not impact these outcomes, nor elicit changes in TSI% or BL concentrations. Novelty Bullets • Training to task failure with low-load blood flow restriction elicits similar improvements to traditional resistance training, regardless of occlusion pressure. • During blood flow restriction, altering occlusion pressure does not proportionally impact tissue O2 saturation nor blood lactate concentrations

Topotactic, pressure-driven, diffusion-less phase transition of layered CsCoO2 to a stuffed cristobalite-type configuration

2019 ◽  
Vol 75 (4) ◽  
pp. 704-710
Author(s):  
Naveed Zafar Ali ◽  
Branton J. Campbell ◽  
Martin Jansen
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Three Dimensional ◽  
Phase Cell ◽  
Ambient Conditions ◽  
Space Group ◽  
Layered Architecture ◽  
Β Phase ◽  
Vertex Sharing ◽  
Two Phases

CsCoO2, featuring a two-dimensional layered architecture of edge- and vertex-linked CoO4 tetrahedra, is subjected to a temperature-driven reversible second-order phase transformation (α → β) at 100 K, which corresponds to a structural relaxation with concurrent tilting and breathing modes of edge-sharing CoO4 tetrahedra. In the present investigation, it was found that pressure induces a phase transition, which encompasses a dramatic change in the connectivity of the tetrahedra. At 923 K and 2 GPa, β-CsCoO2 undergoes a first-order phase transition to a new quenchable high-pressure polymorph, γ-CsCoO2. It is built up of a three-dimensional cristobalite-type network of vertex-sharing CoO4 tetrahedra. According to a Rietveld refinement of high-resolution powder diffraction data, the new high-pressure polymorph γ-CsCoO2 crystallizes in the tetragonal space group I41/amd:2 (Z = 4) with the lattice constants a = 5.8711 (1) and c = 8.3214 (2) Å, corresponding to a shrinkage in volume by 5.7% compared with the ambient-temperature and atmospheric pressure β-CsCoO2 polymorph. The pressure-induced transition (β → γ) is reversible; γ-CsCoO2 stays metastable under ambient conditions, but transforms back to the β-CsCoO2 structure upon heating to 573 K. The transformation pathway revealed is remarkable in that it is topotactic, as is demonstrated through a clean displacive transformation track between the two phases that employs the symmetry of their common subgroup Pb21 a (alternative setting of space group No. 29 that matches the conventional β-phase cell).

Theoretical Analysis of Laser Shock Bulging Forming

2012 ◽  
Vol 472-475 ◽  
pp. 2480-2483 ◽  
Author(s):  
Guo Fang Zhang ◽  
Zhong Ji ◽  
Jing Liu ◽  
Chao Zheng ◽  
Jian Hua Zhang
Keyword(s):  
High Pressure ◽  
Theoretical Analysis ◽  
Analytical Model ◽  
Pulse Energy ◽  
Shock Pressure ◽  
Laser Shock ◽  
Plastic Response ◽  
Forming Process ◽  
Laser Shock Forming ◽  
Plastic Forming

Laser shock forming (LSF) is a novel plastic forming process which utilizes high-pressure plasma to deform thin metals to 3D configurations. The plastic response of a circular plate in laser shock bulging forming was theoretically studied. A simplified shock pressure model was established and then an analytical model was proposed to calculate the deflection. The results show that the deflection increases with increasing pulse energy and the deformation profiles calculated by the analytical model agree well with those of experiment.

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