scholarly journals Electrical conductivity of warm dense silica from double-shock experiments

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Guarguaglini ◽  
F. Soubiran ◽  
J.-A. Hernandez ◽  
A. Benuzzi-Mounaix ◽  
R. Bolis ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Dynamic Compression ◽  
Experimental Studies ◽  
High Energy ◽  
Planetary Science ◽  
Pressure Effects ◽  
High Energy Density ◽  
Hugoniot Curve ◽  
Thermodynamic Conditions ◽  
Reflectivity Data

AbstractUnderstanding materials behaviour under extreme thermodynamic conditions is fundamental in many branches of science, including High-Energy-Density physics, fusion research, material and planetary science. Silica (SiO2) is of primary importance as a key component of rocky planets’ mantles. Dynamic compression is the most promising approach to explore molten silicates under extreme conditions. Although most experimental studies are restricted to the Hugoniot curve, a wider range of conditions must be reached to distill temperature and pressure effects. Here we present direct measurements of equation of state and two-colour reflectivity of double-shocked α-quartz on a large ensemble of thermodynamic conditions, which were until now unexplored. Combining experimental reflectivity data with numerical simulations we determine the electrical conductivity. The latter is almost constant with pressure while highly dependent on temperature, which is consistent with simulations results. Based on our findings, we conclude that dynamo processes are likely in Super-Earths’ mantles.

scholarly journals Liquid Phase Synthesis of CoP Nanoparticles with High Electrical Conductivity for Advanced Energy Storage

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Guo-Qun Zhang ◽  
Bo Li ◽  
Mao-Cheng Liu ◽  
Shang-Ke Yuan ◽  
Leng-Yuan Niu
Keyword(s):  
Electrical Conductivity ◽  
Energy Storage ◽  
Liquid Phase ◽  
Specific Capacitance ◽  
Current Density ◽  
High Surface ◽  
High Surface Area ◽  
High Energy ◽  
High Energy Density ◽  
Energy Storage Materials

Transition metal phosphide alloys possess the metalloid characteristics and superior electrical conductivity and are a kind of high electrical conductive pseudocapacitive materials. Herein, high electrical conductive cobalt phosphide alloys are fabricated through a liquid phase process and a nanoparticles structure with high surface area is obtained. The highest specific capacitance of 286 F g−1 is reached at a current density of 0.5 A g−1. 63.4% of the specific capacitance is retained when the current density increased 16 times and 98.5% of the specific capacitance is maintained after 5000 cycles. The AC//CoP asymmetric supercapacitor also shows a high energy density (21.3 Wh kg−1) and excellent stability (97.8% of the specific capacitance is retained after 5000 cycles). The study provides a new strategy for the construction of high-performance energy storage materials by enhancing their intrinsic electrical conductivity.

scholarly journals Metal-Water mixtures for Propulsion and Energy-Conversion Applications: Recent Progress and Future Directions

2018 ◽  
Vol 20 (1) ◽  
pp. 53 ◽  
Author(s):  
Dilip Sundaram
Keyword(s):  
Particle Size ◽  
Energy Conversion ◽  
Experimental Studies ◽  
High Energy ◽  
High Energy Density ◽  
Full Potential ◽  
Predictive Tool ◽  
Practical Applications ◽  
Relative Safety ◽  
Metal Water

The metal-water system is attractive for propulsion and energy-conversion applications. Of all metals, aluminum is attractive due to its high energy density, relative safety, and low cost. Experimental studies provide new insight on the combustion and propulsive behaviors. The burning rate is found to be a strong function of both pressure and particle size. Furthermore, there is a wide scatter in the measured pressure exponents due to differences in particle size, pressure, pH, and equivalence ratio. A major problem with Al/H2O mixtures is incomplete combustion and poor impulses, thereby rendering Al/H2O mixtures unsuitable for practical applications. Efforts to improve the performance of Al/H2O mixtures have only met with moderate success. Although experiments have revealed these new trends, not much is offered in terms of the underlying physics and mechanisms. To explore the combustion mechanisms, theoretical models based on energy balance analysis have been developed. These models involve numerous assumptions and many complexities were either ignored or treated simplistically. The model also relies on empirical inputs, which makes it more a useful guide than a predictive tool. Future works must endeavor to conduct a more rigorous analysis of metal-water combustion. Empirical inputs should be avoided and complexities must be properly treated to capture the essential physics of the problem. The model should help us properly understand the experimental trends, offer realistic predictions for unexplored conditions, and suggest guidelines and solutions in order to realize the full potential of metal-water mixtures.

The Critical Pressure at the Onset of Flame Instability of Syngas/Air/Diluent Outwardly Expanding Flame at Different Initial Temperatures and Pressures

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Ziyu Wang ◽  
Ziwei Bai ◽  
Guangying Yu ◽  
Sai Yelishala ◽  
Hameed Metghalchi
Keyword(s):  
High Speed ◽  
Critical Pressure ◽  
Hydrodynamic Instability ◽  
Experimental Studies ◽  
Initial Pressure ◽  
High Energy ◽  
Oxide Semiconductor ◽  
High Energy Density ◽  
Flame Instability ◽  
Wide Range

Syngas has gained attention recently due to its high energy density and environmentally friendly characteristics. Flame stability plays an important role in flame propagation in energy conversion devices. Experimental studies were performed in a cylindrical chamber to investigate flame instability of syngas/air/diluent mixture. A Z-shape Schlieren system coupled with a high-speed complementary metal–oxide–semiconductor camera was used to record flame pictures up to 40,000 frames per second. In this research, syngas is a mixture of hydrogen and carbon monoxide and diluent is a blend of 14% CO2 and 86% N2 with the same specific heat as the burned gases. Three main flame instabilities namely Rayleigh–Taylor (body force) instability, hydrodynamic instability, and thermal-diffusive instability have been studied. For the onset of flame instability, a power law correlation for the ratio of critical pressure to initial pressure of syngas/air/diluent flames over a wide range of initial temperatures (298–450 K), initial pressures (1.0–2.0 atm), equivalence ratios (0.6–3.0), diluent concentrations (0–10%), and hydrogen percentages (5–25%) in the fuel has been developed.

Highly Oriented Carbon Nanotube Sheets for Rechargeable Lithium Oxygen Battery Electrodes

2015 ◽  
Vol 15 (10) ◽  
pp. 7611-7614 ◽  
Author(s):  
Seongwoo Ryu ◽  
Byung Gon Kim ◽  
Jang Wook Choi ◽  
Haeshin Lee
Keyword(s):  
Electrical Conductivity ◽  
Mesoporous Structure ◽  
High Energy ◽  
Rechargeable Batteries ◽  
High Energy Density ◽  
Cnt Arrays ◽  
Vertically Aligned ◽  
Lithium Oxygen Battery ◽  
Lithium Oxygen Batteries ◽  
Discharging Capacity

Lithium oxygen batteries are one of the next generation rechargeable batteries. High energy density of lithium oxygen batteries have been considered as a very attractive power option for electric vehicles and many other electronic devices. However, they still faced substantial challenges such as short cycle life, large voltage hysteresis, low gravimetric and volumetric power. Here we developed a highly aligned CNT structured sheet for favorable lithium oxygen cathode electrodes. We fabricated highly oriented CNT sheets by rolling vertically aligned CNT arrays. Highly oriented CNT sheets provide excellent electrical conductivity with favorable mesoporous structure for cathode electrode. As a result, the CNT sheet performed maximum discharging capacity of 1810 mA/gc. We found that electrical conductivity and pore distribution plays important rolls for improving performance in lithium oxygen batteries. This study suggests new strategies of designing highly efficient porous carbon electrodes for lithium oxygen batteries.

Direct Synthesis of Metal Selenide Hybrids as Superior Sodium Storage Anode

2021 ◽  
Author(s):  
Yi Zhang ◽  
Wei Zhong ◽  
Pingping Tan ◽  
Shuang Liu ◽  
Yijun Liu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Energy Density ◽  
Transition Metal ◽  
Direct Synthesis ◽  
High Energy ◽  
Sodium Ion ◽  
High Energy Density ◽  
Sodium Ion Batteries ◽  
Metal Selenides ◽  
Sodium Storage

Transition metal selenides (TMSs) are widely used as anode in sodium-ion batteries (SIBs) due to their good electrical conductivity high energy density. Herein, we reported and prepared a class of...

scholarly journals Investigation on the Reaction Energy, Dynamic Mechanical Behaviors, and Impact-Induced Reaction Characteristics of PTFE/Al with Different TiH2 Percentages

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2008 ◽  
Author(s):  
Zhongshen Yu ◽  
Xiang Fang ◽  
Yuchun Li ◽  
Jiaxiang Wu ◽  
Shuangzhang Wu ◽  
...  
Keyword(s):  
Split Hopkinson Pressure Bar ◽  
Dynamic Compression ◽  
High Energy ◽  
High Energy Density ◽  
Interface Debonding ◽  
Material System ◽  
Reaction Energy ◽  
Reactive Material ◽  
Dynamic Mechanical ◽  
Drop Weight

As a novel energetic material with quite a high energy density, titanium hydride (TiH2) was introduced into a polytetrafluoroethylene/aluminum (PTFE/Al) reactive material system for the first time. The effects of TiH2 on the reaction energy, dynamic mechanical responses, and reaction properties of the composites were investigated through adiabatic bomb calorimeter, split-Hopkinson pressure bar, and drop-weight experiments. The results show that the reaction heat of the composites improved significantly as the content of TiH2 increased. Under dynamic compression, these composites show obvious strain hardening and strain rate hardening effects. Besides, a certain amount of TiH2 granules helps to improve the material’s compressive strength, and the maximum would even reach 173.2 MPa with 5% TiH2 percentage, 10.1% higher than that of PTFE/Al. Mesoscale images of the samples after dynamic compression indicate that interface debonding between the particles and PTFE matrix and the fracture of the PTFE matrix are the two major mechanisms resulting in the material’s failure. In addition, the drop-weight experiments indicate that the material’s impact sensitivities are sensitive to the content of TiH2, which would be increased to within 20% of the content of TiH2 compared with PTFE/Al, and the reaction degree is also improved to within 10% of the content of TiH2. The retrieved reaction residues after drop-weight experiments imply that the reaction is initiated at the edges of the samples, indicating a shear-induced initiation mechanism of this kind of reactive material.

scholarly journals A study on fabrication, manipulation and survival of cryogenic targets required for the experiments at the Facility for Antiproton and Ion Research: FAIR

2009 ◽  
Vol 27 (2) ◽  
pp. 255-272 ◽  
Author(s):  
E.R. Koresheva ◽  
I.V. Aleksandrova ◽  
E.L. Koshelev ◽  
A.I. Nikitenko ◽  
T.P. Timasheva ◽  
...  
Keyword(s):  
Energy Density ◽  
Heavy Ion ◽  
High Energy ◽  
Planetary Science ◽  
Ion Beams ◽  
High Energy Density ◽  
Cryogenic System ◽  
Experimental Chamber ◽  
First Time ◽  
Density Matter

AbstractCylindrical cryogenic targets are required to carry out the Laboratory Planetary Science scheme of the experiments of the High Energy Density matter Generated by Heavy Ion Beams collaboration at FAIR. In this paper, for the first time a thorough analysis of the problem of such targets' fabrication, delivery and positioning in the center of the experimental chamber has been made. Particular attention is paid to the issue of a specialized cryogenic system creation intended for rep-rate supply of the High Energy Density matter Generated by Heavy Ion Beams experiments with the cylindrical cryogenic targets.

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