The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Jeanne M Shreeve - One of the best experts on this subject based on the ideXlab platform.
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potassium 4 5 bis dinitromethyl furoxanate a green primary explosive with a positive oxygen balance
Angewandte Chemie, 2016Co-Authors: Jeanne M ShreeveAbstract:Potassium 4,5-bis(dinitromethyl)furoxanate was synthesized readily from cyanoacetic acid. It was characterized by IR spectroscopy, elemental analysis, NMR spectroscopy, and differential scanning calorimetry (DSC), and the structure was confirmed by X-ray single-crystal diffraction. Its positive oxygen balance, high density (2.130 g cm−3), sensitivity (IS=2 J, FS=5 N), and calculated Heat of Formation (−421.0 kJ mol−1), combined with its calculated superior detonation performance (D=7759.0 m s−1, P=27.3 GPa), make it a competitive replacement as a green primary explosive.
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trinitromethyl substituted 5 nitro or 3 azo 1 2 4 triazoles synthesis characterization and energetic properties
Journal of the American Chemical Society, 2011Co-Authors: Venugopal Thottempudi, Haixiang Gao, Jeanne M ShreeveAbstract:Various new polynitro-1,2,4-triazoles containing a trinitromethyl group were synthesized by straightforward routes. These high nitrogen and oxygen-rich compounds were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis, natural bonding orbital (NBO) analysis, and differential scanning calorimetry (DSC) and, in the case of 12, with single crystal X-ray structuring. The Heats of Formation for all compounds were calculated with Gaussian 03 (revision D.01) and then combined with experimentally determined densities to determine detonation pressures (P) and velocities (D) of the energetic materials (Cheetah 5.0). They exhibit high density, good thermal stability, acceptable oxygen balance, positive Heat of Formation, and excellent detonation properties, which, in some cases, are superior to those of TNT, RDX, and HMX.
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bis 3 5 nitroimino 1 2 4 triazolate based energetic salts synthesis and promising properties of a new family of high density insensitive materials
Journal of the American Chemical Society, 2010Co-Authors: Ruihu Wang, Hongyan Xu, Rongjian Sa, Jeanne M ShreeveAbstract:Bis[3-(5-nitroimino-1,2,4-triazolate)]-based energetic salts were synthesized in a simple, straightforward manner. They exhibit low solubility in available solvents, high hydrolytic stability, excellent thermal stability, high density, positive Heat of Formation, low shock sensitivity, and excellent detonation properties. The physical and energetic properties of some salts are similar and even superior to those of RDX.
Masaaki Nishikawa - One of the best experts on this subject based on the ideXlab platform.
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molecular dynamics simulation of cross linking processes and material properties for epoxy resins using first principle calculation combined with global reaction route mapping algorithms
Chemical Physics Letters, 2021Co-Authors: Yutaka Oya, Masahiro Nakazawa, Keiichi Shirasu, Yuki Hino, Kyosuke Inuyama, Gota Kikugawa, Riichi Kuwahara, Naoki Kishimoto, Hiroki Waizumi, Masaaki NishikawaAbstract:Abstract Herein, epoxy resin is cured by coupling quantum chemical calculations with molecular dynamics simulations that enable the prediction of material characteristics with fewer artificial parameters. A polymer network is formed by the reaction between base resin and curing agent. The reaction uses activation energy and Heat of Formation data obtained by first-principle calculations coupled with global reaction route mapping algorithms. Density, glass-transition temperature, Young’s modulus, and curing conversion are used to validate the procedure. Experimental and simulation results indicate that base resin with multi-functional reaction groups increase glass-transition temperature and Young’s modulus because of cross-linking at the molecular scale.
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curing reaction of epoxy resin composed of mixed base resin and curing agent experiments and molecular simulation
Polymer, 2013Co-Authors: Tomonaga Okabe, Tomohiro Takehara, Noriyuki Hirano, Masaaki Nishikawa, Keisuke Inose, Takuya UeharaAbstract:Abstract In this study, we investigated the influence of base resin and curing agent and their mixture on the curing characteristics by performing experiments and molecular simulations. In the curing experiment of epoxy resin, we used differential scanning calorimetry (DSC) to obtain the conversion by mixing curing agents and base resins. We used the molecular orbital method (MO) and the molecular dynamics method (MD) to simulate the curing reaction in molecular scale and investigate the effect of differences in resin composition on the curing characteristics. This simulation took into consideration activation energy, Heat of Formation, and polarization in the curing reaction. The simulation captures the trend of curing reaction obtained by the experiment. We found that the selection and mixture of curing agents are very important when controlling the curing characteristics of epoxy resin.
Yutaka Oya - One of the best experts on this subject based on the ideXlab platform.
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molecular dynamics simulation of cross linking processes and material properties for epoxy resins using first principle calculation combined with global reaction route mapping algorithms
Chemical Physics Letters, 2021Co-Authors: Yutaka Oya, Masahiro Nakazawa, Keiichi Shirasu, Yuki Hino, Kyosuke Inuyama, Gota Kikugawa, Riichi Kuwahara, Naoki Kishimoto, Hiroki Waizumi, Masaaki NishikawaAbstract:Abstract Herein, epoxy resin is cured by coupling quantum chemical calculations with molecular dynamics simulations that enable the prediction of material characteristics with fewer artificial parameters. A polymer network is formed by the reaction between base resin and curing agent. The reaction uses activation energy and Heat of Formation data obtained by first-principle calculations coupled with global reaction route mapping algorithms. Density, glass-transition temperature, Young’s modulus, and curing conversion are used to validate the procedure. Experimental and simulation results indicate that base resin with multi-functional reaction groups increase glass-transition temperature and Young’s modulus because of cross-linking at the molecular scale.
R De Reus - One of the best experts on this subject based on the ideXlab platform.
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prediction of phase Formation sequence and phase stability in binary metal aluminum thin film systems using the effective Heat of Formation rule
Journal of Applied Physics, 1991Co-Authors: R Pretorius, A M Vredenberg, F W Saris, R De ReusAbstract:The effective Heat of Formation (ΔH’) concept allows Heats of Formation to be calculated as a function of concentration. In this work the effective Heat of Formation rule is used to predict first phase Formation in metal‐aluminum thin‐film systems and to predict subsequent phase sequence for thin metal films on thick aluminum or thin aluminum on thick metal substrates. The effective concentration at the growth interface is taken to be that of the lowest temperature eutectic (liquidus) for the binary system. Although the effective Heat of Formation rule may predict that Formation of a certain phase would lead to the largest free energy change, this phase does not necessarily form at the moving reaction interface if it has difficulty to nucleate. By excluding phases with a large number of atoms per unit cell and which thus have difficulty to nucleate, the effective Heat of Formation rule successfully predicts first phase aluminide Formation for all 15 metal‐aluminum binary systems for which experimental data could be found. It is also shown how the effective Heat of Formation rule can be used to predict Formation and decomposition of aluminide phases in contact with each other or in contact with their component metals.
Venugopal Thottempudi - One of the best experts on this subject based on the ideXlab platform.
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trinitromethyl substituted 5 nitro or 3 azo 1 2 4 triazoles synthesis characterization and energetic properties
Journal of the American Chemical Society, 2011Co-Authors: Venugopal Thottempudi, Haixiang Gao, Jeanne M ShreeveAbstract:Various new polynitro-1,2,4-triazoles containing a trinitromethyl group were synthesized by straightforward routes. These high nitrogen and oxygen-rich compounds were fully characterized using IR and multinuclear NMR spectroscopy, elemental analysis, natural bonding orbital (NBO) analysis, and differential scanning calorimetry (DSC) and, in the case of 12, with single crystal X-ray structuring. The Heats of Formation for all compounds were calculated with Gaussian 03 (revision D.01) and then combined with experimentally determined densities to determine detonation pressures (P) and velocities (D) of the energetic materials (Cheetah 5.0). They exhibit high density, good thermal stability, acceptable oxygen balance, positive Heat of Formation, and excellent detonation properties, which, in some cases, are superior to those of TNT, RDX, and HMX.
