scholarly journals Cooling rates of LL, L and H chondrites and constraints on the duration of peak thermal conditions: Diffusion kinetic modeling and implications for fragmentation of asteroids and impact resetting of petrologic types

2016 ◽  
Vol 192 ◽  
pp. 135-148 ◽  
Author(s):  
Jibamitra Ganguly ◽  
Massimiliano Tirone ◽  
Kenneth Domanik
Keyword(s):  
Kinetic Modeling ◽  
Thermal Conditions ◽  
Diffusion Kinetic ◽  
Cooling Rates ◽  
H Chondrites

scholarly journals Exploring the Effects of MXene on Nonisothermal Crystallization and Melting Behavior of β-Nucleated Isotactic Polypropylene

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3815
Author(s):  
Wanxin Peng ◽  
Furui Sun ◽  
Yuke Liang ◽  
Jian Kang ◽  
Jinyao Chen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Isotactic Polypropylene ◽  
Isothermal Crystallization ◽  
Polarized Light ◽  
Thermal Conditions ◽  
Melting Behavior ◽  
Polymorphic Behavior ◽  
Scanning Calorimetry ◽  
Cooling Rates ◽  
Thermal Stability Of

In this study, one of the commonly used MXene (Ti3C2Tx) and β nucleated isotactic polypropylene (β-iPP)/MXene composites of different compositions were fabricated. The effects of MXene on non-isothermal crystallization and polymorphic behavior of β-iPP/MXene composites were comparatively studied. The non-isothermal crystallization kinetics indicates that for all samples, the lower cooling rates promote composites to crystallize at higher temperatures. When MXene and β-Nucleating agent (β-NA) are added separately, the crystallization temperature of composites shifts towards higher temperatures at all cooling rates. When MXene and β-NA are added simultaneously, the composite shows different cooling rate dependence, and the effects of improving crystallization temperatures is more obvious under rapid cooling. The activation energy of four samples iPP, iPP/MXene, iPP/β-NA, and iPP/MXene/β-NA were −167.5, −185.5, −233.8, and −218.1 kJ/mol respectively, which agree with the variation tendency of crystallization temperatures. The polymorphic behavior analysis obtained from Differential Scanning calorimetry (DSC) is affected by two factors: the ability to form β-crystals and the thermal stability of β-crystals. Because β-crystals tend to recrystallize to α-crystals below a critical temperature, to eliminate the effect of β-α recrystallization, the melting curves at end temperatures Tend = 50 °C and Tend = 100 °C are comparatively studied. The results show that more thermally unstable β-crystals would participate in β-α recrystallization with higher cooling rates. Moreover, thermal stability of β-crystals is improved by adding MXene. To further verify these findings, samples of three different thermal conditions were synthesized and analyzed by DSC, X-Ray Diffraction (XRD), and Polarized Light Optical Microscopy (PLOM), and the results were consistent with the above findings. New understandings of synthesizing β-iPP/MXene composites with adjustable morphologies and polymorphic behavior were proposed.

Early Palaeozoic intracratonic shears and post-tectonic cooling in the Rauer Group, Prydz Bay, East Antarctica constrained by40Ar/39Ar thermochronology

2007 ◽  
Vol 19 (3) ◽  
pp. 339-353 ◽  
Author(s):  
Christopher J.L. Wilson ◽  
Cameron Quinn ◽  
Laixi Tong ◽  
David Phillips
Keyword(s):  
Structural Evolution ◽  
Thermal Conditions ◽  
Shear Zones ◽  
Ductile Deformation ◽  
Prydz Bay ◽  
Cooling Rates ◽  
Deformation Event ◽  
Thermal Histories ◽  
Early Palaeozoic ◽  
Field Variability

AbstractThe Rauer Group, in Prydz Bay, contains reworked Archaean-Proterozoic crust in high-strain zones that formed during a pervasive high-temperature ductile deformation event related to intracratonic mechanisms. The effects of this event extend southwards from Prydz Bay into the southern Prince Charles Mountains. The associated structural evolution involved development of ductile and brittle structures that formed during an approximately north–south directed transpressional deformation event that is confined to high-grade (>800°C) shear zones in the Rauer Group. Minerals from the Rauer Group, yield40Ar/39Ar cooling ages ranging from 560 to 460 Ma. Thermal histories derived from hornblende, biotite and feldspar suggest that the onset of rapid cooling began sometime prior to 510 Ma with cooling rates ofc. 42 to 33°C myr-1fromc. 510 Ma toc. 500 Ma. Whereas,40Ar/39Ar data obtained from plagioclase and K–feldspar suggest a slower cooling fromc. 500 Ma toc. 460 Ma with cooling rates from 5 to 2°C myr-1. These results demonstrate that the early Palaeozoic cooling history and comparable palaeostress regimes are regionally extensive, which has important implications for the tectonothermal and stress-field variability across Gondwana. The elevated thermal conditions would induce lithospheric weakening and promote the early Palaeozoic intraplate orogeny observed in eastern Antarctica with the development of a large intracratonic shear system.

244 Pu fission track thermometry and its application to stony meteorites

1981 ◽  
Vol 374 (1757) ◽  
pp. 253-270 ◽  
Keyword(s):  
Central Region ◽  
Shell Structure ◽  
Fission Track ◽  
Track Detector ◽  
Ordinary Chondrites ◽  
Cooling Rates ◽  
Multiple Fission ◽  
Detector Method ◽  
H Chondrites

Revised cooling rates, obtained from mineral separates of several ordinary chondrites by means of the multiple fission track detector method, are presented. Especially for the H chondrites, these new data lead to major revisions of the previously published results. They are consistent with an ‘onion-shell’ structure of the parent asteroids of ordinary chondrites, in which petrologic type 6 materials resided near the central region, and types 5, 4 and 3 in the outer shells. The diameters of these asteroids are estimated to be between 100 and 140 km for the H body, greater than 200 km for the L body, and 220-300 km for the LL body.

Diffusion Kinetic Modeling of Fluoride Removal from Aqueous Solution by Charge-Reversed Zeolite Particles

2005 ◽  
Vol 38 (9) ◽  
pp. 701-710 ◽  
Author(s):  
Maurice S. Onyango ◽  
Yoshihiro Kojima ◽  
Dalibor Kuchar ◽  
Simon O. Osembo ◽  
Hitoki Matsuda
Keyword(s):  
Aqueous Solution ◽  
Kinetic Modeling ◽  
Fluoride Removal ◽  
Diffusion Kinetic

Diffusion−Kinetic Modeling of the γ-Radiolysis of Liquid Cycloalkanes

1997 ◽  
Vol 101 (8) ◽  
pp. 1628-1634 ◽  
Author(s):  
Jay A. LaVerne ◽  
Simon M. Pimblott ◽  
Laszlo Wojnarovits
Keyword(s):  
Kinetic Modeling ◽  
Diffusion Kinetic

C–H Bond Activation ofMethane with Gaseous [(CH3)Pt(L)]+ Complexes (L = Pyridine, Bipyridine, and Phenanthroline)

2007 ◽  
Vol 62 (3) ◽  
pp. 309-313 ◽  
Author(s):  
Burkhard Butschke ◽  
Maria Schlangen ◽  
Helmut Schwarz ◽  
Detlef Schröder
Keyword(s):  
Experimental Data ◽  
Detailed Analysis ◽  
Electrospray Ionization ◽  
Kinetic Modeling ◽  
Bond Activation ◽  
Oxidative Addition ◽  
Thermal Conditions ◽  
Nitrogen Ligand ◽  
Insight Into

Electrospray ionization of solutions of dimethyl(1,5-cyclooctadiene)platinum(II) in methanol with traces of nitrogen-containing ligands L provides gaseous complexes of the type [(CH3)Pt(L)]+ with L = pyridine (py), 2,2′-bipyridine (bipy), and 1,10-phenanthroline (phen). These [(CH3)Pt(L)]+ cations are capable of activating the C-H bond in methane as shown by H/D exchange when using CD4 as a neutral reactant. Most reactive is the complex [(CH3)Pt(py)]+ bearing a monodentate nitrogen ligand. The cationic complexes [(CH3)Pt(bipy)]+ and [(CH3)Pt(phen)]+ also bring about activation of methane, though at a lower rate, whereas the bipyridine complex [(CH3)Pt(py)2]+ does not react with methane at thermal conditions. A detailed analysis of the experimental data by means of kinetic modeling provides insight into the underlying mechanistic steps, but a distinction whether the reaction occurs as σ bond metathesis or via an oxidative addition cannot be made on the basis of the experimental data available.

Allene oxidation in jet-stirred reactor : a kinetic modeling study

1990 ◽  
Vol 87 ◽  
pp. 1159-1172 ◽  
Author(s):  
P Dagaut ◽  
M Cathonnet ◽  
B Aboussi ◽  
JC Boettner
Keyword(s):  
Kinetic Modeling ◽  
Stirred Reactor ◽  
Allene Oxidation ◽  
Modeling Study
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