scholarly journals Chelate Coordination Compounds as a New Class of High-Energy Materials: The Case of Nitro-Bis(Acetylacetonato) Complexes

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5438
Author(s):  
Danijela S. Kretić ◽  
Ivana S. Veljković ◽  
Aleksandra B. Đunović ◽  
Dušan Ž. Veljković
Keyword(s):  
Electrostatic Potential ◽  
High Performance ◽  
Density Functional ◽  
High Efficiency ◽  
High Energy ◽  
Molecular Surface ◽  
Energy Materials ◽  
Dissociation Energies ◽  
Central Regions ◽  
And Performance

The existence of areas of strongly positive electrostatic potential in the central regions of the molecular surface of high-energy molecules is a strong indicator that these compounds are very sensitive towards detonation. Development of high-energy compounds with reduced sensitivity towards detonation and high efficiency is hard to achieve since the energetic molecules with high performance are usually very sensitive. Here we used Density Functional Theory (DFT) calculations to study a series of bis(acetylacetonato) and nitro-bis(acetylacetonato) complexes and to elucidate their potential application as energy compounds with moderate sensitivities. We calculated electrostatic potential maps for these molecules and analyzed values of positive potential in the central portions of molecular surfaces in the context of their sensitivity towards detonation. Results of the analysis of the electrostatic potential demonstrated that nitro-bis(acetylacetonato) complexes of Cu and Zn have similar values of electrostatic potential in the central regions (25.25 and 25.06 kcal/mol, respectively) as conventional explosives like TNT (23.76 kcal/mol). Results of analysis of electrostatic potentials and bond dissociation energies for the C-NO2 bond indicate that nitro-bis(acetylacetonato) complexes could be used as potential energetic compounds with satisfactory sensitivity and performance.

scholarly journals Theoretical and Experimental Sets of Choice Anode/Cathode Architectonics for High-Performance Full-Scale LIB Built-up Models

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
H. Khalifa ◽  
S. A. El-Safty ◽  
A. Reda ◽  
M. A. Shenashen ◽  
M. M. Selim ◽  
...  
Keyword(s):  
High Performance ◽  
Density Functional ◽  
Coulombic Efficiency ◽  
Density Functional Theory Calculation ◽  
Scale Up ◽  
Lithium Ion ◽  
Building Blocks ◽  
High Energy ◽  
Full Scale ◽  
High Energy Density

Abstract To control the power hierarchy design of lithium-ion battery (LIB) built-up sets for electric vehicles (EVs), we offer intensive theoretical and experimental sets of choice anode/cathode architectonics that can be modulated in full-scale LIB built-up models. As primary structural tectonics, heterogeneous composite superstructures of full-cell-LIB (anode//cathode) electrodes were designed in closely packed flower agave rosettes TiO2@C (FRTO@C anode) and vertical-star-tower LiFePO4@C (VST@C cathode) building blocks to regulate the electron/ion movement in the three-dimensional axes and orientation pathways. The superpower hierarchy surfaces and multi-directional orientation components may create isosurface potential electrodes with mobile electron movements, in-to-out interplay electron dominances, and electron/charge cloud distributions. This study is the first to evaluate the hotkeys of choice anode/cathode architectonics to assemble different LIB–electrode platforms with high-mobility electron/ion flows and high-performance capacity functionalities. Density functional theory calculation revealed that the FRTO@C anode and VST-(i)@C cathode architectonics are a superior choice for the configuration of full-scale LIB built-up models. The integrated FRTO@C//VST-(i)@C full-scale LIB retains a huge discharge capacity (~ 94.2%), an average Coulombic efficiency of 99.85% after 2000 cycles at 1 C, and a high energy density of 127 Wh kg−1, thereby satisfying scale-up commercial EV requirements.

Spreading of SARS-CoV-2 via Heating, Ventilation, and Air Conditioning Systems—An Overview of Energy Perspective and Potential Solutions

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Ahmad K. Sleiti ◽  
Samer F. Ahmed ◽  
Saud A. Ghani
Keyword(s):  
Air Conditioning ◽  
High Performance ◽  
Public Perception ◽  
High Efficiency ◽  
Uv Light ◽  
Experimental Studies ◽  
High Energy ◽  
Penalty Cost ◽  
Energy Penalty ◽  
Air Conditioning Systems

Abstract The role of heating, ventilation, and air conditioning systems (HVAC) in spreading SARS-CoV-2 is a complex topic and has not been studied thoroughly. There are some existing strategies and technologies for health and high performance buildings; however, applications to other types of buildings come at large energy penalty: cost; design, regulations and standards changes, and varied public perception. In the present work, different factors and strategies are reviewed and discussed and suggested mitigations and solutions are provided including the required air flowrates with the presence of infectors with and without mask and disinfection techniques including ultraviolet (UV) light. Experimental and numerical research in open literature suggests that the airborne transmission of SARS-CoV-2 is sufficiently likely. However, in situ detailed experimental studies are still needed to understand the different scenarios of the virus spread. Displacement ventilation, underfloor air distribution, chilled beams, radiant ceiling panels, and laminar flow systems have varied effectiveness. High-efficiency particulate arrestance (HEPA) filters and UV light can clean viruses but at high energy cost. Suggested solutions to reduce the infection probability include recommended levels of ventilation and a combination of virus sampling technologies including cyclones, liquid impinger, filters, electrostatic precipitators, and water-based condensation.

Computer Simulation of the Magnesium Silicide Polymorphs

2012 ◽  
Vol 170-173 ◽  
pp. 3312-3315
Author(s):  
Dong Chen ◽  
Chao Xu
Keyword(s):  
Optical Properties ◽  
Energy Region ◽  
High Performance ◽  
Density Functional ◽  
High Energy ◽  
Magnesium Silicide ◽  
High Energy Region ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Pseudo Potential

The anti-cotunnite magnesium silicide was constructed, and its absorption coefficient, dielectric function and loss function have been investigated through the plane-wave pseudo- potential calculations based on the density functional theory. In our scheme, we consider the Mg2Si crystal without defects or cracks. Significant features have been observed for the optical properties in the low-energy region and the high-energy region. The main focus of this paper is to determine the high-pressure optical properties of Mg2Si and find out if this material can be used as high-performance thermoelectric devices.

scholarly journals 1,2,5-Oxadiazole-1,2,3,4-Tetrazole Based High Energy Materials: Molecule Design and Screen

2020 ◽  
Author(s):  
Xinghui Jin ◽  
Menghui Xiao ◽  
Jianhua Zhou ◽  
Bingcheng Hu
Keyword(s):  
High Energy ◽  
High Energy Density ◽  
Heats Of Formation ◽  
Detonation Properties ◽  
Bond Dissociation Energies ◽  
Energy Materials ◽  
Thermal Stabilities ◽  
High Energy Materials ◽  
Bond Dissociation ◽  
Dissociation Energies

A series of 1,2,5-oxadiazole-1,2,3,4-tetrazole based high energy materials were theoretically designed and investigated. Their heats of formation, detonation properties and thermal stabilities were calculated by isodesmic reactions, Kamlet-Jacobs equations and bond dissociation energies, respectively. The results show that all the designed compounds possess high positive heats of formation and the –N=N–/–N3 substituents were found to be more helpful in improving the heats of formation than other substituents. The change tendency of densities, detonation pressures and detonation velocities were approximately the same to each other which suggests that values of densities were the key parameter to detonation properties rather than other parameters. In view of bond dissociation energies, the –CN/–NH2 substituents will be helpful to improve the thermal stabilities of the designed compounds while the other substituents/bridges will decrease their thermal stabilities to some extent. Take detonation properties and thermal stabilities into consideration, six compounds (C7, D3, D7, F7, G7 and H7) were selected as potential high energy density compounds since they had higher detonation properties and thermal stabilities than those of RDX. Finally, electronic structures (such as distribution of frontier molecular orbitals and electrostatic potentials) of the selected compounds were simulated to give a better understanding of these compounds.

Graphene oxide-polypyrrole composite as sulfur hosts for high-performance lithium-sulfur batteries

2018 ◽  
Vol 11 (06) ◽  
pp. 1840007 ◽  
Author(s):  
Qian Wang ◽  
Chengkai Yang ◽  
Hui Tang ◽  
Kai Wu ◽  
Henghui Zhou
Keyword(s):  
Graphene Oxide ◽  
High Performance ◽  
Density Functional ◽  
Specific Capacity ◽  
High Energy ◽  
High Energy Density ◽  
Composite Cathodes ◽  
Lithium Sulfur Batteries ◽  
Lithium Sulfur ◽  
Capacity Decay

Lithium-sulfur batteries are considered as a promising candidate for the next-generation high energy density storage devices. However, they are still hindered by serious capacity decay on cycling caused by the dissolution of redox intermediates. Here, we designed a unique structure with polypyrrole (ppy) inserting into the graphene oxide (GO) sheet for accommodating sulfur. Such a sulfur host not only exhibits a good electronic and ionic conductivity, but also can suppress polysulfide dissolution effectively. With this advanced design, the composite cathode showed a high specific capacity of 548.4[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text] at 5.0 C. A stable Coulombic efficiency of [Formula: see text]99.5% and a capacity decay rate as low as 0.089% per cycle along with 300 cycles at 1.0 C were achieved for composite cathodes with 78[Formula: see text]wt.% of S. Besides, the interaction mechanism between PPy and lithium polysulfides (LPS) was investigated by density-functional theory (DFT), suggesting that only the polymerization of N atoms can bind strongly to Li ions of LPS rather than single N atoms. The 3D structure GO-PPy host with high conductivity and excellent trapping ability to LPS offered a viable strategy to design high-performance cathodes for Li–S batteries.

scholarly journals Recent Advances in Synthesis and Properties of Nitrated-Pyrazoles Based Energetic Compounds

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3475 ◽  
Author(s):  
Shijie Zhang ◽  
Zhenguo Gao ◽  
Di Lan ◽  
Qian Jia ◽  
Ning Liu ◽  
...  
Keyword(s):  
Energetic Materials ◽  
High Performance ◽  
High Efficiency ◽  
Low Cost ◽  
Rapid Development ◽  
Development Trend ◽  
High Heat ◽  
High Energy ◽  
Heat Of Formation ◽  
Energetic Compounds

Nitrated-pyrazole-based energetic compounds have attracted wide publicity in the field of energetic materials (EMs) due to their high heat of formation, high density, tailored thermal stability, and detonation performance. Many nitrated-pyrazole-based energetic compounds have been developed to meet the increasing demands of high power, low sensitivity, and eco-friendly environment, and they have good applications in explosives, propellants, and pyrotechnics. Continuous and growing efforts have been committed to promote the rapid development of nitrated-pyrazole-based EMs in the last decade, especially through large amounts of Chinese research. Some of the ultimate aims of nitrated-pyrazole-based materials are to develop potential candidates of castable explosives, explore novel insensitive high energy materials, search for low cost synthesis strategies, high efficiency, and green environmental protection, and further widen the applications of EMs. This review article aims to present the recent processes in the synthesis and physical and explosive performances of the nitrated-pyrazole-based Ems, including monopyrazoles with nitro, bispyrazoles with nitro, nitropyrazolo[4,3-c]pyrazoles, and their derivatives, and to comb the development trend of these compounds. This review intends to prompt fresh concepts for designing prominent high-performance nitropyrazole-based EMs.

scholarly journals Thermodynamics and Performance Projections for Intercooled/Reheat/Recuperated Gas Turbine Systems

1987 ◽  
Author(s):  
Maher A. El-Masri
Keyword(s):  
Gas Turbine ◽  
High Performance ◽  
High Efficiency ◽  
Pure Water ◽  
Water Injection ◽  
Component Technology ◽  
Specific Power ◽  
Combined Cycles ◽  
And Performance ◽  
Marine Applications

Intercooled/Recuperated gas turbine systems provide high-efficiency and power density for naval propulsion. Current aero-derivative systems are capable of about 43% thermal efficiency in this configuration. With continued progress in gas-turbine materials and cooling technology, the possibility of further improving system performance by incorporation of gas-turbine reheat arises. A preliminary scan of this class of cycles is presented and compared with non-reheat intercooled/recuperated cycles at two levels of component technology. For conservative component technology, the reheat is found to provide very modest performance advantages. With advanced components and ceramic thermal barrier coatings, the reheat is found to offer potential for specific power improvements of up to 33% and for modest efficiency gains, on the order of one percentage point, while enabling turbine inlet temperatures well below those for the most efficient non-reheat cycles. The high-performance reheat systems, however, require reheat-combustor inlet temperatures beyond current practice. The use of water-injection in the intercooler, together with an aftercooler and a water-injected evaporative-recuperator is found to produce very large gains in efficiency as well as specific power. This modification may be feasible for land-based systems, where it can compete favourably with combined cycles. Despite the difficulty of obtaining pure water for a shipboard propulsion system, those large gains may justify further studies of this system and of means to provide its water supply in marine applications.

SCO Trimers as High-energy Materials? A Density Functional Study

2000 ◽  
Vol 6 (2) ◽  
pp. 55-64 ◽  
Author(s):  
María J. Mayor-López ◽  
Jacques Weber ◽  
Hans P. Lüthi ◽  
Kaspar Hegetschweiler
Keyword(s):  
Density Functional ◽  
High Energy ◽  
Functional Study ◽  
Energy Materials ◽  
Density Functional Study ◽  
High Energy Materials

scholarly journals A General Self-Sacrifice Template Strategy to 3D Heteroatom-Doped Macroporous Carbon for High-Performance Potassium-Ion Hybrid Capacitors

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Junwei Li ◽  
Xiang Hu ◽  
Guobao Zhong ◽  
Yangjie Liu ◽  
Yaxin Ji ◽  
...  
Keyword(s):  
Energy Density ◽  
High Performance ◽  
Density Functional ◽  
High Energy ◽  
Potassium Ion ◽  
High Energy Density ◽  
Capacitance Performance ◽  
Hybrid Capacitors ◽  
Co Doped ◽  
Macroporous Carbon

AbstractPotassium-ion hybrid capacitors (PIHCs) tactfully combining capacitor-type cathode with battery-type anode have recently attracted increasing attentions due to their advantages of decent energy density, high power density, and low cost; the mismatches of capacity and kinetics between capacitor-type cathode and battery-type anode in PIHCs yet hinder their overall performance output. Herein, based on prediction of density functional theory calculations, we find Se/N co-doped porous carbon is a promising candidate for K+ storage and thus develop a simple and universal self-sacrifice template method to fabricate Se and N co-doped three-dimensional (3D) macroporous carbon (Se/N-3DMpC), which features favorable properties of connective hierarchical pores, expanded interlayer structure, and rich activity site for boosting pseudocapacitive activity and kinetics toward K+ storage anode and enhancing capacitance performance for the reversible anion adsorption/desorption cathode. As expected, the as-assembled PIHCs full cell with a working voltage as high as 4.0 V delivers a high energy density of 186 Wh kg−1 and a power output of 8100 W kg−1 as well as excellent long service life. The proof-of-concept PIHCs with excellent performance open a new avenue for the development and application of high-performance hybrid capacitors.

scholarly journals Density Functional Theory Calculations on Nitrated Boroxines as Possible High Energy-Density Materials

2017 ◽  
Vol 117 (2) ◽  
pp. 27 ◽  
Author(s):  
Lisa M. Ina ◽  
David W. Ball
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Minimum Energy ◽  
Normal Modes ◽  
Density Functional Theory Calculations ◽  
Combustion Products ◽  
High Energy ◽  
High Energy Density ◽  
Energy Materials ◽  
Functional Theory

Density functional theory calculations were performed on a series of nitroboroxine molecules (cyclo-[BO]3-[NO2]xH3-x, x = 1 – 3) to determine their thermodynamic properties and assess them as potential high energy materials.  Minimum-energy geometries of four boroxine molecules were determined, along with their normal modes of vibration.  Analysis of the energies of the molecules and their possible decomposition and combustion products suggests an energy contact comparable to that of TNT.

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