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Wyszukujesz frazę "energy density" wg kryterium: Temat


Tytuł:
Aminonitronaphthalenes as Possible High Energy Density Materials
Autorzy:
Murawski, R. J.
Ball, D. W.
Powiązania:
https://bibliotekanauki.pl/articles/358002.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
high energy density materials
aminonitronaphthalenes
density functional theory calculations
Opis:
As part of a series of studies evaluating the thermodynamic properties of new potential high energy materials, a series of calculations was performed on a variety of naphthalene molecules having amino and nitro groups. Calculations on seven aminonitronaphthalene molecules were performed, determining their minimum-energy geometries, vibrational frequencies, and energies. Enthalpies of formation were determined using atomization reactions, and subsequently enthalpies of combustion or decomposition were determined. Specific enthalpies of decomposition ranged from 4.1-4.8 kJ/g, while specific enthalpies of combustion ranged more widely, from 13 to almost 21 kJ/g. Some detonation properties of some of the derivatives rival those of current HEDMs.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 1; 3-12
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
FE model for linear-elastic mixed mode loading: estimation of SIFs and crack propagation
Autorzy:
Boulenouar, A
Benseddiq, N.
Mazari, M
Benamara, N
Powiązania:
https://bibliotekanauki.pl/articles/949326.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
crack propagation
stress intensity factor
strain energy density
Opis:
Finite element analysis combined with the concepts of linear elastic fracture mechanics provides a practical and convenient means to study the fracture and crack growth of materials. The onset criterion of crack propagation is based on the stress intensity factor, which is the most important parameter that must be accurately estimated and facilitated by the singular element. The displacement extrapolation technique is employed to obtain the SIFs at crack tip. In this paper, two different crack growth criteria and the respective crack paths prediction for several test cases are compared between the circumferential stress criterion and the strain energy density criterion. Several examples are presented to compare each criterion and to show the robustness of the numerical schemes.
Źródło:
Journal of Theoretical and Applied Mechanics; 2014, 52, 2; 373-383
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Study on Nitroimine Derivatives of Azetidine as High-Energy-Density Compounds
Autorzy:
Li, Bu-tong
Li, Lu-lin
Powiązania:
https://bibliotekanauki.pl/articles/358762.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
high-energy-density compounds
Kamlet-Jacobs equations
azetidin derivatives
Opis:
A series of derivatives of azetidine were designed by stepwise replacing the hydrogen atoms of azetidine with nitroimine groups. At the G3MP2 level, the heats of formation (HOFs), bond dissociation energies (BDEs), molecular densities (ρ0), detonation velocities (D), and detonation pressures (P) of the nitroimine-substituted azetidines were investigated to look for high-energy-density compounds (HEDCs). It was found that the nitroimine-substituted azetidines have high HOFs and large BDEs, and sufficient thermal and kinetic stability. Furthermore, the covalent bond strength in the four-membered ring, accompanied by intramolecular hydrogen bonds, are the determining factors for isomer stability. Based on our calculations, derivatives E and F have better detonation performance than RDX and can be regarded as potential high-energy-density compounds. This work may provide basic information for further study of the title compounds.
Źródło:
Central European Journal of Energetic Materials; 2020, 17, 1; 107-118
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlation between Microstructure and Exothermic Reaction Kinetics of Al-CuO Thermite Nanocomposite Powders Fabricated by Cryomilling
Autorzy:
Oh, Minseok
Kim, Kwanil
Ahn, Byungmin
Powiązania:
https://bibliotekanauki.pl/articles/355529.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-CuO
thermite
nanocomposite
cryomilling
high energy density materials
Opis:
Al-CuO is a thermite material exhibiting the exothermic reaction only when aluminum melts. For wide spread of its applica-tion, the reaction temperature needs to be reduced in addition to the enhancement of total reaction energy. In the present study, a thermite nanocomposite with a large contact area between Al and CuO was fabricated in order to lower the exothermic reaction temperature and to improve the reactivity. A cryomilling process was performed to achieve the nanostructure, and the effect of composition on the microstructure and its reactivity was studied in detail. The microstructure was characterized using SEM and XRD, and the thermal property was analyzed using DSC. The results show that as the molar ratio between Al and CuO varies, the fraction of uniform nanocomposite structure was changed affecting the exothermic reaction characteristics.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 931-934
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A strain energy density theory for mixed mode crack propagation in rubber-like materials
Autorzy:
Boulenouar, A.
Benseddiq, N.
Merzoug, M.
Benamara, N.
Mazari, M.
Powiązania:
https://bibliotekanauki.pl/articles/279872.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
strain energy density
mixed mode
hyper-elastic
crack propagation
Opis:
In this paper, a numerical modeling of crack propagation for rubber-like materials is presented. This technique aims at simulating the crack growth under mixed-mode loading based on the strain energy density approach. At each crack increment length, the kinking angle is evaluated as a function of the minimum strain energy density (MSED) around the crack tip, using the Ansys Parametric Design Language (APDL). In this work, numerical examples are illustrated to demonstrate the effectiveness, robustness and accuracy of the computational algorithm to predict the crack propagation path. The results obtained show that the plan of crack propagation is perpendicular to the direction of the maximum principal stretch. Moreover, in the framework of linear elastic fracture mechanics (LEFM), the minimum values of the density are reached at the points corresponding to the crack propagation direction.
Źródło:
Journal of Theoretical and Applied Mechanics; 2016, 54, 4; 1417-1431
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic Quantum Vacuum and Relativity
Autorzy:
Fiscaletti, Davide
Powiązania:
https://bibliotekanauki.pl/articles/763387.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
energy density of quantum vacuum, Sagnac effect, relativity, dark energy, Mercury precession.
Opis:
A model of a three-dimensional dynamic quantum vacuum with variable energy density is proposed. In this model, time we measure with clocks is only a mathematical parameter of changes running in quantum vacuum. Mass and gravity are carried by the variable energy density of quantum vacuum. Each elementary particle is a structure of quantum vacuum and diminishes the quantum vacuum energy density. Symmetry “particle – diminished energy density of quantum vacuum” is the fundamental symmetry of the universe which gives origin to the inertial and gravitational mass. Special relativity’s Sagnac effect in GPS system and important predictions of general relativity such as precessions of the planets, the Shapiro time delay of light signals in a gravitational field and the geodetic and frame-dragging effects recently tested by Gravity Probe B, have origin in the dynamics of the quantum vacuum which rotates with the earth.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio AAA – Physica; 2016, 71
0137-6861
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio AAA – Physica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phenomenological modeling of mechanical properties of metal foam
Modelowanie metodą fenomenologiczną mechanicznych właściwości pian metalowych
Autorzy:
Wegner, T.
Kurpisz, D.
Powiązania:
https://bibliotekanauki.pl/articles/949201.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
metal foam
strain energy density function
phenomenological method of modeling
energy conservation principle
Opis:
In this paper, constitutive relations for metal foam under complex load are introduced using a phenomenological concept. On the basis of stress-strain and transversal-longitudinal strain dependencies in uniaxial tests, a form of the function for strain energy density is specified, and further, the criterion for loss of stability due to the occurrence of plastic flow is defined. The theoretical investigations are illustrated by a short numerical example.
W niniejszej pracy, bazując na fenomenologicznym sposobie podejścia, wyprowadzono związki konstytutywne piany metalowej poddanej złożonemu stanowi obciążenia. Na podstawie zależności naprężenia oraz odkształcenia poprzecznego od odkształcenia podłużnego uzyskanych w jednoosiowych próbach, wyznaczono wzór opisujący funkcję gęstości energii wewnętrznej, a następnie sformułowano analityczną postać kryteriów zniszczenia materiału ze względu na wystąpienie plastycznego płynięcia. Rozważania teoretyczne zilustrowano prostym przykładem numerycznym.
Źródło:
Journal of Theoretical and Applied Mechanics; 2013, 51, 1; 203-214
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An energy-based method in phenomenological description of mechanical properties of nonlinear materials under plane stress
Autorzy:
Wegner, T.
Kurpisz, D.
Powiązania:
https://bibliotekanauki.pl/articles/279443.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
energy-based method
nonlinear material
phenomenological description
strain energy density function
Sylvester’s theorem
Opis:
A method based on energy is a very useful tool for description of mechanical properties of materials. In the current paper, on the base of geometrical interpretation of a deformation process, the strain energy density function for isotropic nonlinear materials has been constructed. On account of hydrostatic interpretation of the volumetric deformation, the elastic part of energy has been extracted. The initiation of the damage process due to plastic flow of the material under plane stress has been determined and the stability conditions have been formulated by using in the stability analysis the strain energy density function in addition to Sylvester’s theorem and assumption of zero volume change during pure plastic deformations. This concept is an original part of the work and continuation of the investigations previously carried out by Wegner and Kurpisz. The theoretical investigations have been illustrated on the example of aluminium.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 129-139
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anisotropic charged stars with quadratic equation state
Autorzy:
Malaver, Manuel
Powiązania:
https://bibliotekanauki.pl/articles/1178297.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Anisotropic charged matter distribution; compact stellar objects; energy density; quadratic equation of state
Opis:
In this paper, we present a new model of static spherically symmetric relativistic compact stellar objects with anisotropic charged matter distribution and quadratic equation of state together with a prescribed form for the gravitational potential Z used by Bhar and Murad (2016). A graphical analysis of the physical properties indicate indicates that the new model well behaved and not admit singularities in the matter and the charge density.
Źródło:
World Scientific News; 2017, 86, 3; 333-344
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Chemical Study of Aminonitrocyclopentanes as Possible High Energy Density Materials (HEDMs)
Autorzy:
Bai, J.
Chi, W. J.
Li, L. L.
Yan, T.
Wen, X. E.
Li, B. T.
Wu, H. S.
Ma, F. L.
Powiązania:
https://bibliotekanauki.pl/articles/358101.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
cyclopentane derivatives
high energy density materials
impact sensitivity
quantum chemistry
DFT
available free space
Opis:
Nitro and amine groups were introduced into the cyclopentane skeleton, and the heats of formation, detonation performance, bond dissociation energies, and impact sensitivity for these aminonitrocyclopentanes were calculated in detail at the B3LYP/6-311G** level. The results show that all of the derivatives have negative heats of formation, which are influenced by the position of the substituent groups. Their stabilities were estimated and analyzed according to their bond dissociation energies and calculated characteristic H50 values. Most of the compounds were found to have a lower impact sensitivity than HMX. Furthermore, the detonation velocities and detonation pressures were predicted via the Kamlet-Jacobs equation. Of all these aminonitrocyclopentanes, E has the best detonation properties (ρ = 2.05 g/cm3, D = 9.11 m/s, P = 39.62 GPa) and can be considered as a candidate high energy density material.
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 4; 467-480
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calorimetric studies of the energy deposition on a material surface by plasma jets generated with QSPA and MPC devices
Autorzy:
Chuvilo, A. A.
Garkusha, I. E.
Makhlaj, V. A.
Petrov, Y. V.
Powiązania:
https://bibliotekanauki.pl/articles/147706.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
quasi steady-state plasma accelerator (QSPA)
energy density
heat load
plasma streams
plasma-surface interaction
Opis:
Studies of the energy deposition by plasma jets incident on a material surface are of topical interest for both the fusion and plasma technology applications. In this paper the results are reported of a comparative study of plasma energy deposition on different material surfaces exposed to plasma jets of various duration and energy density, generated using the QSPA Kh-50 and the MPC devices. The spatial distribution of plasma energy density and the heat load on the surface were measured with a movable calorimeter. The measurements demonstrate that in the case of an exposure to QSPA plasma jets the absorbed heat load is approximately equal to 55-60% of the energy in the incident plasma jet. In the case of plasma jets generated using the MPC device the heat load on the target surface and was practically the same as for the QSPA jets, and additional shielding effects were found to be negligible due to the short duration of plasma jets.
Źródło:
Nukleonika; 2012, 57, 1; 49-53
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical Studies of High-nitrogen-containing Energetic Compounds Based on the s-Tetrazine Unit
Autorzy:
Man, T. T.
Wang, K.
Zhang, J.G.
Niu, X. Q.
Zhang, T. L.
Powiązania:
https://bibliotekanauki.pl/articles/358527.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
high-energy-density materials (HEDMs)
substituted s-tetrazine
compounds
electronic properties
thermodynamic properties
detonation
properties
Opis:
In order to develop new high-energy-density materials (HEDMs), we have investigated 12 substituted s-tetrazine (TZ) compounds, where s-tetrazine was substituted by amino, amido and related groups. Density functional theory (DFT) was used to predict the optimized geometries, electronic structures, total energy, heats of formation (HOFs) and densities. In addition the detonation properties were evaluated by using the VLW equation of state (EOS). The standard enthalpy of formation, the Gibbs free energy, entropy and equilibrium constants were used to estimate the success of the synthetic substitution reactions, which provided theoretical support for practical work. The bond dissociation energy (BDE) of bond C-R was calculated at each stage of the substitution reaction. The calculated results showed that substitution of amino, amido and their derivatives in the TZ ring enhances the HOF values and is favorable for increasing the thermal stability. The calculated detonation properties indicated that incorporating the above groups into the TZ ring is benefcial for improving the explosive performance. Considering the detonation properties and thermal stability, the 12 derivatives may be regarded as promising candidates as high-energy-density materials (HEDMs).
Źródło:
Central European Journal of Energetic Materials; 2013, 10, 2; 171-189
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical models for quark stars with electric field
Autorzy:
Malaver, Manuel
Powiązania:
https://bibliotekanauki.pl/articles/1178867.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Einstein-Maxwell system
MIT Bag Model
adjustable parameter
charged quark matter
energy density
gravitational potential
Opis:
We found new class of solutions to the Einstein-Maxwell system of equations for charged quark matter within the framework of MIT Bag Model considering a prescribed form of gravitational potential Z(x) used by Malaver (2016), which depends on an adjustable parameter n. Variables as the energy density, charge density, pressure and the metric functions are written in terms of elementary and polynomial functions. We show that the form chosen for the gravitational potential allows obtain physically acceptable solutions with any value of the adjustable parameter.
Źródło:
World Scientific News; 2017, 89; 39-47
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Estimation of Fatigue Crack Initiation Life of H62 Brass
Autorzy:
Zheng, M.
Zhang, S.
Peng, Xiao Jian
Wang, Yi
Powiązania:
https://bibliotekanauki.pl/articles/2048866.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
strain energy density
fatigue damage strain
theoretical strain fatigue limit
fatigue crack initiation
life prediction
Opis:
In the present paper, the excavation of the energetic approach that estimates the fatigue crack initiation life of metal is conducted for H62 brass. The benefit of the energetic approach is the division of the actual applied strain range Δε into two parts, that is, a damage strain range Δεd that induces fatigue damage within the metal, and an undamaged strain range Δεc, which does not produce fatigue damage of the metal and corresponds to theoretical strain fatigue limit. The brightness of this approach is that the undamaged strain range Δεc can be estimated by the fundamental conventional parameters of metal in tensile test. The result indicated that the fatigue crack initiation life of H62 brass can be estimated by this approach successfully.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 1; 31-35
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Role of initial density distribution in simulations of bone remodeling around dental implants
Autorzy:
Nutu, E.
Powiązania:
https://bibliotekanauki.pl/articles/307275.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
energia odkształcenia
kość
warunki początkowe
przebudowa kości
strain energy density
bone quantity
initial conditions
bone remodeling simulation
Opis:
In this paper, the effect of initial density distribution upon the predicted density via numerical simulations of bone remodeling was evaluated. The main purpose was to correlate the numerical results with clinical data according to which the initial bone quantity is an essential factor for long term survival of dental implants. Methods: Two-strain energy density-based bone remodeling theories were employed, one which accounts for overload resorption and the second one, which does not. The remodeling parameters were derived from the mechanostat theory. Bone remodeling around an osseointegrated dental implant was simulated based on finite element method using a generic mandible plane model. A variable time step was introduced to increase the speed of the remodeling simulations by keeping the truncation errors small. The simulations were performed for several initial density distributions correlated with values from clinical classifications of bone quality. For each density value, the occlusal load was defined in two ways so that to consider normal and overload mastication forces, respectively. Results: The results showed that the initial density distribution influences the predictions of bone remodeling simulations. For the analyzed model, the remodeling algorithm predicted overload resorption only in the case of low initial density, which can be associated with low bone quality, which, from clinical perspective, may probably lead to implant loss. Conclusions: The paper demonstrated that when simulating bone remodeling around dental implants using finite element method, it is important to account for initial density distribution in correlation with the bone quantity.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 4; 23-31
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł

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