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Theoretical Simulations on Physicochemical Performance of Novel High-energy BHDBT-based Propellants

Wang Ke, Huang Hai-tao, Xu Hui-xiang, Li Huan, Li Jun-qiang, Fan Xue-zhong, Pang Wei-qiang

Central European Journal of Energetic Materials

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2021

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Vol. 18, no. 1

5--24

EN

Based on Energy Calculation Star program and molecular dynamic method, three designed 2,3-bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol tetranitrate-based (BHDBT) propellants are firstly reported and their physicochemical performance are investigated. Results suggest that compared with HMX-based and CL-20-based propellants, the specific impulses of all BHDBT-based propellants surpass or approximate 280 s, which indicates the latter have the potential to be high-energy propellants. The diffusion coefficient of plasticizers in BHDBT-based propellant decrease as the temperature reduces, and reduce in the order: Bu-NENA > TMETN > BTTN. The densities of all BHDBT-based propellants surpass or approximate 1.7 g/cm3. The comparison of elastic constants, Poisson’s ratios and K/G values indicates that the mechanical properties of three BHDBT-based propellants increase in the order (by plasticizer): Bu-NENA < TMETN < BTTN. The bond length analysis of C–NO2 and O–NO2 bond in BHDBT suggests that the former is the trigger bond in the BHDBT-based propellants, and the safety of BHDBT-based propellants and BHDBT crystal decreases in the order: GAP/BTTN/Al/BHDBT > GAP/Bu-NENA/Al/BHDBT ≈ GAP/TMETN/Al/BHDBT > BHDBT. In conclusion, GAP/BTTN/Al/BHDBT propellant has the potential to be a novel high-energy propellant.

2

Application of Fragment Molecular Orbital Method to investigate dopamine receptors

Preikša Jokūbas, Śliwa Paweł

Science, Technology and Innovation

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2019

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Vol. 6, no. 3

24--32

EN

GPCRs are a vast family of seven-domain transmembrane proteins. This family includes dopamine receptors (D1, D2, D3, D4, and D5), which mediate the variety of dopamine-controlled physiological functions in the brain and periphery. Ligands of dopamine receptors are used for managing several neuropsychiatric disorders, including bipolar disorder, schizophrenia, anxiety, and Parkinson’s disease. Recent studies have revealed that dopamine receptors could be part of multiple signaling cascades, rather than of a single signaling pathway. For these targets, a variety of experimental and computational drug design techniques are utilized. In this work, dopamine receptors D2, D3, and D4 were investigated using molecular dynamic method as well as computational ab initio Fragment Molecular Orbital method (FMO), which can reveal atomistic details about ligand binding. The results provided useful insights into the significances of amino acid residues in ligand binding sites. Moreover, similarities and differences between active-sites of three studied types of receptors were examined.

3

Molecular dynamic simulations study of 2-((2- (decyloxy)ethyl)amino)lauric acid adsorption on the α-quartz (1 0 1) surface

Luo Binbin, Zhu Yimin, Sun Chuanyao, Li Yanjun, Han Yuexin

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 5

1209--1216

EN

Adsorption mechanism of a novel amphoteric collector 2-((2-(decyloxy)ethyl)amino)lauric acid (CH3(CH2)9CH(NH(CH2)3-O-(CH2)9CH3)COOH, LDEA) on the α-quartz (1 0 1) surface has been investigated through molecular dynamic (MD) simulation calculations at a molecular level. The adsorption process showed that the LDEA collector could be adsorbed onto α-quartz’s (1 0 1) surface as the H atom in the polar carboxyl and amino functional group of the collector moved closer to the O atom of quartz (1 0 1) surface. The interaction energies of the collector LDEA molecule and its ionic derivative species on α-quartz surfaces in vacuum and aqueous solutions are in the order of pH 4 < pH 12 < in vacuum < pH 10 < pH 6, which demonstrating that the α-quartz (1 0 1) surface could absorb the collector LDEA in the forms of electrostatic and hydrogen bonding interactions. It also reveals that the optimal pulp pH range for LDEA adsorption on α-quartz’s surface is between neutral and weak alkali environment (pH 6 - 10). The trend obtained from molecular modeling has been validated by microflotation studies on quartz at different pHs.

4

A nanoscale simulation study of elastic properties of gaspeite

Benazzouz B.-K.

Studia Geotechnica et Mechanica

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2014

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Vol. 36, nr 2

9--16

EN

The study of structural and mechanical properties of carbonate rock is an interesting subject in engineering and its different applications. In this paper, the crystal structure of gaspeite (NiCO3) is investigated by carrying out molecular dynamics simulations based on energy minimization technique using an interatomic interaction potential. At first, we focus on the structural properties of gaspeite mineral. And then, the elastic properties are calculated, including the elastic constants, bulk modulus, shear modulus, the S- and P-wave velocities. In the next part of this paper, the pressure effect will be studied on the structural and elastic properties of NiCO3 at high pressure.

5

Studies of trans- and cis-xylomollin molecular structures using molecular dynamics simulations

Mahboub R.

International Letters of Chemistry, Physics and Astronomy

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2012

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Vol. 5

46-58

EN

The present work describes the comparative study of the trans- and the cis-xylomollin structures. We have determined the two bridgehead H5 and H9 configurations using simulation calculations for both trans- and cis- distereoisomers. Molecular Dynamic (MD) simulations of the trans- and cis- xylomollin were performed with an efficient program. The geometries, interaction energies, bonds, angles, and the Van der Waals (VDW) interactions were carried out in solution and gas phases. This comparative study shows that the trans-xylomollin acquires the high configuration energy under the AMBER field using MD method. This molecule reaches its high stable configuration state in solution environment. Our MD simulation results are goods and in agreement with those of literature.

6

Dextran complexes with single-walled carbon nanotubes

Stobiński L., Polaczek E., Rębilas K., Mazurkiewicz J., Wrzalik R., Lin H. M., Tomasik P.

Polimery

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2008

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T. 53, nr 7-8

571-575

EN

Formation of surface and inclusion complexes of single-walled carbon nanotubes (SWCNT) with dextrans of Mw 6000 to 2 000 000 was proven spectrally, rheologically, and calorimetrically. Band shifts in the Raman spectra, increase in the viscosity of aqueous solutions of particular dextrans after admixture of SWCNT, and enthalpies of melting of those complexes were independent on molecular weight of dextrans. Computational simulations were performed using the HyperChem 7 and Gaussian 03 packages, starting from a model of single, short SWCNT and linear dextran chain made of 12, 18 or 24 ß-D-glucose units. The simulation indicated that dextran chains composed of 12 or 18 ß-D-glucose units only partly enveloped SWCNT and the intermolecular interactions in both terminals of the chains prevailed. The dextran containing 24 ß-D-glucose units fully enveloped SWCNT. However, the role of SWCNT in the envelop formation was limited solely to its hydrophobic interactions with the central part of the dextran chain.

PL

Metodą spektroskopii Ramana (rys. 1, tabela 1), oraz na podstawie wyników badań reologicznych (tabela 2) i kalorymetrycznych (DSC, tabela 3) potwierdzono powstawanie kompleksów dekstranów o ciężarze cząsteczkowym (Mw) z przedziału 6000-2 000 000 z jednościennymi nanorurkami węglowymi (SWCNT). Przesunięcia pasm w widmach Ramana, wzrost lepkości wodnych roztworów dekstranów po dodaniu SWCNT oraz wartości entalpii topnienia powstających kompleksów nie zależały od ciężaru cząsteczkowego użytego dekstranu. W odniesieniu do modelowych, krótkich nanorurek węglowych i liniowych dekstranów zbudowanych z 12, 18 lub 24 jednostek ß-D-glukozowych wykonano komputerowe symulacje posługując się programami HyperChem 7 i Gaussian 03 (rys. 2-4). Stwierdzono, że dwa pierwsze dekstrany tylko częściowo otaczają nanorurkę, natomiast ich końce zawijają się w wyniku oddziaływań wewnątrzcząsteczkowych o charakterze wiązań wodorowych. Dopiero najdłuższy dekstran całkowicie owija nanorurkę, ale jej udział w tworzeniu otoczki sprowadza się jedynie do hydrofobowych oddziaływań ze środkową częścią łańcucha dekstranu.

7

Atomic configurations of breaking nanocontacts of aluminium and nickel

Garcia-Mochales P., Serena P. A., Guerrero C., Medina E., Hasmy A.

Materials Science Poland

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2005

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Vol. 23, No. 2

407--411

EN

A statistical study of favourable atomic configurations of aluminium and nickel nanocontacts during their fracture at 4 K and 300 K was performed. Nanowire breaking events are simulated by using molecular dynamics ( MD), the atomic interactions being represented by the state-of-the-art embedded atom method (EAM) interatomic potentials, which are able to fit bulk and surface properties with a high degree of accuracy. A complete determination of atomic positions during the contact allows evaluation of the evolution of the minimum-cross section Sm during stretching. By accumulating Sm traces, obtained from many independent fractures of nanowires, minimum cross-section histograms H( Sm) were built. These simulated histograms reveal the presence of preferential geometrical arrangements during the breaking of the nanocontact and allow a direct comparison with experimental conductance histograms. In particular, aluminium histograms show a remarkable agreement between conductance and minimum cross-section peaks. However for Ni, the interpretation of experimental conductance peaks is more difficult due to the presence of magnetic effects and the possible presence of contaminants.