The Effect of Pulsed Laser Heating on the Stability of Ferropericlase at High Pressures

It is widely accepted that the lower mantle consists of mainly three major minerals—ferropericlase, bridgmanite and calcium silicate perovskite. Ferropericlase ((Mg,Fe)O) is the second most abundant of the three, comprising approximately 16–20 wt% of the lower mantle. The stability of ferropericlase at conditions of the lowermost mantle has been highly investigated, with controversial results. Amongst other reasons, the experimental conditions during laser heating (such as duration and achieved temperature) have been suggested as a possible explanation for the discrepancy. In this study, we investigate the effect of pulsed laser heating on the stability of ferropericlase, with a geochemically relevant composition of Mg0.76Fe0.24O (Fp24) at pressure conditions corresponding to the upper part of the lower mantle and at a wide temperature range. We report on the decomposition of Fp24 with the formation of a high-pressure (Mg,Fe)3O4 phase with CaTi2O4-type structure, as well as the dissociation of Fp24 into Fe-rich and Mg-rich phases induced by pulsed laser heating. Our results provide further arguments that the chemical composition of the lower mantle is more complex than initially thought, and that the compositional inhomogeneity is not only a characteristic of the lowermost part, but includes depths as shallow as below the transition zone.

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Melting curve determination under high pressure using pulsed laser heating in a diamond anvil cell: Application to cerium

High Pressure Research ◽

10.1080/08957959408206144 ◽

1994 ◽

Vol 12 (3) ◽

pp. 175-186 ◽

Cited By ~ 11

Author(s):

B. Sitaud ◽

J. Péré ◽

Th. Thévenin

Keyword(s):

High Pressure ◽

Laser Heating ◽

Diamond Anvil Cell ◽

Melting Curve ◽

Pulsed Laser ◽

Diamond Anvil ◽

Curve Determination ◽

Pulsed Laser Heating

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Real-time changes induced by pulsed laser heating in ammonium perchlorate at static high pressures

10.1063/1.55584 ◽

1998 ◽

Author(s):

G. I. Pangilinan ◽

T. P. Russell

Keyword(s):

Real Time ◽

Ammonium Perchlorate ◽

Laser Heating ◽

High Pressures ◽

Pulsed Laser ◽

Time Changes ◽

Pulsed Laser Heating

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Apparatus for processing of samples at high pressures and high temperatures in a fast quenching-rate regime and synthesis of polyacetylene by pulsed laser heating of confined carbon thin films

Journal of Applied Physics ◽

10.1063/1.3561501 ◽

2011 ◽

Vol 109 (6) ◽

pp. 063529

Author(s):

M. L. Andreazza ◽

C. A. Perottoni ◽

J. A. H. da Jornada

Keyword(s):

Thin Films ◽

High Temperatures ◽

Laser Heating ◽

High Pressures ◽

Pulsed Laser ◽

Quenching Rate ◽

Carbon Thin Films ◽

Pulsed Laser Heating ◽

Fast Quenching

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On the Negative Excess Isotherms for Methane Adsorption at High Pressure: Modeling and Experiment

SPE Journal ◽

10.2118/197045-pa ◽

2019 ◽

Vol 24 (06) ◽

pp. 2504-2525 ◽

Cited By ~ 3

Author(s):

Jing Li ◽

Keliu Wu ◽

Zhangxin Chen ◽

Kun Wang ◽

Jia Luo ◽

...

Keyword(s):

High Pressure ◽

Mass Balance ◽

High Pressures ◽

Pore Wall ◽

Void Volume ◽

Excess Adsorption ◽

Experimental Conditions ◽

Accessible Volume ◽

Adsorbed Phase

Summary An excess adsorption amount obtained in experiments is always determined by mass balance with a void volume measured by helium (He) –expansion tests. However, He, with a small kinetic diameter, can penetrate into narrow pores in porous media that are inaccessible to adsorbate gases [e.g., methane (CH4)]. Thus, the actual accessible volume for a specific adsorbate is always overestimated by an He–based void volume; such overestimation directly leads to errors in the determination of excess isotherms in the laboratory, such as “negative isotherms” for gas adsorption at high pressures, which further affects an accurate description of total gas in place (GIP) for shale–gas reservoirs. In this work, the mass balance for determining the adsorbed amount is rewritten, and two particular concepts, an “apparent excess adsorption” and an “actual excess adsorption,” are considered. Apparent adsorption is directly determined by an He–based volume, corresponding to the traditional treatment in experimental conditions, whereas actual adsorption is determined by an adsorbate–accessible volume, where pore–wall potential is always nonpositive (i.e., an attractive molecule/pore–wall interaction). Results show the following: The apparent excess isotherm determined by the He–based volume gradually becomes negative at high pressures, but the actual one determined by the adsorbate–accessible volume always remains positive.The negative adsorption phenomenon in the apparent excess isotherm is a result of the overestimation in the adsorbate–accessible volume, and a larger overestimation leads to an earlier appearance of this negative adsorption.The positive amount in the actual excess isotherm indicates that the adsorbed phase is always denser than the bulk gas because of the molecule/pore–wall attraction aiding the compression of the adsorbed molecules. Practically, an overestimation in pore volume (PV) is only 3.74% for our studied sample, but it leads to an underestimation reaching up to 22.1% in the actual excess amount at geologic conditions (i.e., approximately 47 MPa and approximately 384 K). Such an overestimation in PV also underestimates the proportions of the adsorbed–gas amount to the free–gas amount and to the total GIP. Therefore, our present work underlines the importance of a void volume in the determination of adsorption isotherms; moreover, we establish a path for a more–accurate evaluation of gas storage in geologic shale reservoirs with high pressure.

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Pulsed laser heating of soot: morphological changes

Carbon ◽

10.1016/s0008-6223(98)00169-9 ◽

1999 ◽

Vol 37 (2) ◽

pp. 231-239 ◽

Cited By ~ 80

Author(s):

Randy L Vander Wal ◽

Mun Y Choi

Keyword(s):

Laser Heating ◽

Morphological Changes ◽

Pulsed Laser ◽

Pulsed Laser Heating

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Thermal Modeling of the Cavity in Pulsed Excimer Laser Calorimeters

10.1115/imece2000-1574 ◽

2000 ◽

Author(s):

D. H. Chen ◽

Z. M. Zhang

Keyword(s):

Laser Heating ◽

Average Power ◽

Pulsed Laser ◽

Thermal Response ◽

Element Model ◽

Electrical Heating ◽

Deep Ultraviolet ◽

Simplified Finite Element Model ◽

193 Nm ◽

Pulsed Laser Heating

Abstract A simplified finite element model is built to study the thermal response of the 193-nm pulsed-laser calorimeter. The nonequivalence between pulsed-laser heating and electrical heating is estimated to be 0.46% at the thermocouple locations by comparing the calibration factors for average-power laser heating and electrical heating. This study should help the development of calibration and measurement standards in pulsed energy measurements for deep ultraviolet excimer lasers that are important for photolithographic and materials processing applications.

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