Article
Chemistry, Multidisciplinary
Albina A. Valeeva, Stanislav Sadovnikov, Aleksandr Gusev
Summary: Phase transformations in nanocrystalline silver sulfide (Ag2S) were systematically studied, and different polymorphic modifications were identified. It was found that the interstitial spacings between silver ions in the superionic phases were smaller than the ion diameter. The transitions between different polymorphic modifications occurred as first-order phase transformations at specific temperatures. The interface structure formed between Ag2S and ZnS was investigated, considering the elastic properties of these sulfides. It was found that a large amount of cubic zinc sulfide stabilized the cubic structure of beta-Ag2S argentite during the co-deposition of Ag2S/ZnS heteronanostructures. The most energetically favorable formation of Ag2S/ZnS heteronanostructures was identified, and the relationship between elastic characteristics and interface structure was analyzed.
Article
Chemistry, Physical
S. I. Sadovnikov, A. I. Gusev
Summary: Measurements of the heat capacity of superionic silver sulfide indicate that nanocrystalline argentite has a higher heat capacity than coarse-crystalline argentite due to limitations of the phonon spectrum imposed by the small particle size. As temperature increases, the elastic characteristics of argentite decrease, leading to a reduction in elastic anisotropy.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Stanislav I. Sadovnikov, Maksim G. Kostenko, Aleksandr I. Gusev, Aleksey V. Lukoyanov
Summary: In this study, the evolutionary algorithm was used for the first time to perform a broad search for low-temperature Ag2S phases of silver sulfide. It was found that the formation of low-symmetry Ag2S phases is energetically most favorable. The mechanical stability and electronic state densities of these predicted Ag2S phases were also calculated. These findings indicate the possibility of synthesizing new silver sulfide phases with improved properties.
Article
Physics, Multidisciplinary
S. I. Sadovnikov, A. I. Gusev
Summary: The relative positions of atomic planes of low-temperature monoclinic acanthite alpha-Ag2S and high-temperature bcc argentite beta-Ag2S have been determined from X-ray and electron microscopy data. The reversible phase transition between beta-Ag2S and alpha-Ag2S is due to the distortion in the bcc S sublattice. The filling probabilities of sites in the metal sublattice differ between the two structures, leading to different distances between Ag atoms in the crystals.
Article
Chemistry, Inorganic & Nuclear
Evgeniy V. Bogdanov, Evgeniy I. Pogoreltsev, Mikhail V. Gorev, Svetlana V. Mel'nikova, Maxim S. M. Olokeev, Natalia M. Laptash, Igor N. Flerov
Summary: The effect of a change in internal pressure caused by partial substitution of the central atom on the realization and stability of crystalline phases in (NH4)3TixSn1-xF7 solid solutions has been investigated. It was found that at Ti concentrations between x = 0.15-0.40, the transformation between Pm-3m and Pa-3 phases is transformed into a sequence of phase transitions. With increasing Ti concentration, the stability of the Pm-3m cubic phase decreases and the predicted high-temperature cubic phase appears.
JOURNAL OF SOLID STATE CHEMISTRY
(2023)
Article
Construction & Building Technology
Waleska Barbosa, Tulio Honorio
Summary: This study investigates the structure and properties of triclinic tricalcium silicate, providing valuable data for understanding the contribution of polymorphs in cement systems.
CEMENT AND CONCRETE RESEARCH
(2022)
Article
Thermodynamics
M. B. Tang, X. C. Liu, M. H. Zhang, X. H. Pan
Summary: Heat capacity is an important subject in condensed matter physics. Previous studies have shown that the change in heat dQ depends on the macroscopic physical variables dT and dlnV in general solids. In this paper, we analyze the thermal parameters during the melting process in a series of reference materials and explain the behavior of heat of fusion and volume change using a new heat capacity model. The results provide insights into the volume-dependent heat capacity model and the melting process in general materials.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
Julia Hartwig, Valeriy Galkin
Summary: The cell parameters of synthetic pyrope were measured using X-ray powder diffraction method in the temperature range 100-630 K. Experimental data was interpolated and extrapolated using the Debye-Mie-Gruneisen theory from 50 to 2000 K. Temperature dependencies of molar volumes, coefficients of volume thermal expansion, Gruneisen coefficient, Debye temperature, heat capacity, and elastic parameters were determined up to 2000 K.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Physics, Condensed Matter
M. B. Tang, X. C. Liu, M. H. Zhang, X. H. Pan
Summary: In this study, the scaling behavior of non-volume-dependent heat capacity in solids was systematically explored. It was found that in the temperature dimension, the non-volume-dependent heat capacity can be scaled by Debye function, while the potential heat capacity is linearly dependent on thermal expansion. These new findings are crucial for quantitatively separating potential and kinetic heat capacity from experimental data.
SOLID STATE COMMUNICATIONS
(2022)
Article
Construction & Building Technology
Tulio Honorio, Helena Carasek, Oswaldo Cascudo
Summary: In this study, molecular simulations were performed to compute the physical properties of Friedel's salt and provide the temperature-dependent thermoelastic properties. These findings are important for the application of Friedel's salt data in multiscale modeling.
CEMENT AND CONCRETE RESEARCH
(2022)
Article
Engineering, Marine
Afnan Y. Alsayed, Mohammed A. Alsaafani, Abdullah M. Al-Subhi, Turki M. Alraddadi, Ahmed M. Taqi
Summary: This study evaluates the seasonal variability in surface heat content in the Arabian Gulf using hydrographic data. Results show that the northern part of the Gulf has lower ocean heat content (OHC) compared to the southeastern part during winter. The highest OHC in the Gulf occurs in September and October, while the lowest is observed in February and March.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Chemistry, Physical
Zahrah Ramadlan Mubarokah, Norsuria Mahmed, Mohd Natashah Norizan, Ili Salwani Mohamad, Mohd Mustafa Al Bakri Abdullah, Katarzyna Bloch, Marcin Nabialek, Madalina Simona Baltatu, Andrei Victor Sandu, Petrica Vizureanu
Summary: A silver sulfide (Ag2S) semiconductor photocatalyst film was successfully synthesized using a solution casting method. The study showed that incorporating Ag2S powder into cellulose films reduced the peak intensity of oxygen-containing functional groups, indicating the formation of a composite film. The crystal structure analysis confirmed a monoclinic acanthite Ag2S structure for all prepared samples, and the photocatalytic efficiency of CF/comAg(2)S and CF/syntAg(2)S films was significantly higher compared to bare Ag2S powder under sunlight exposure.
Article
Materials Science, Multidisciplinary
Janete E. Zorzi, Claudio A. Perottoni
Summary: A heuristic approach for analyzing the thermal expansion of materials has been proposed, comparing two models and estimating the effect of pressure on the molar heat capacity of graphite.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Chemistry, Physical
Si-Yuan Ge, Rui-Kang Huang, Jia-bing Wu, Kiyonori Takahashi, Chi-Sing Lee, Takayoshi Nakamura
Summary: In this study, a novel organic crystalline supramolecular rotor, [(3-chloro-1-adamantylammonium)-(18-crown-6)]-ClO4, was reported, exhibiting planar positive-zero-negative thermal expansion along the a- and c-axes, with zero thermal expansion behavior in the range of 250-317K. X-ray single-crystal structures, differential scanning calorimetry (DSC) measurements, and molecular dynamics simulations revealed that this unique transition in thermal expansion is a result of the static-swing-rotation transition of 18-crown-6 in the crystal structure.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Abdusalam Alkhwaji, Salem Elbahloul, Mohd Zulkifly Abdullah, Khairil Fadzli Bin Abu Bakar
Summary: Water is the most commonly used fluid in heat transfer applications, and estimating its thermal properties efficiently and reliably is important. This study proposes using molecular dynamic simulations to calculate water thermal properties, which can be used as an effective and relatively cheap tool to investigate thermal and dynamic properties of working fluids in thermofluid design. Experimental results show that simulated values are close to reliable published values, indicating the usefulness of molecular dynamics simulations.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Physical
Stanislav Sadovnikov, Aleksey Ishchenko, Ilya A. Weinstein
JOURNAL OF ALLOYS AND COMPOUNDS
(2020)
Article
Chemistry, Inorganic & Nuclear
S. I. Sadovnikov
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY
(2020)
Article
Physics, Multidisciplinary
S. I. Sadovnikov
Article
Materials Science, Multidisciplinary
Albina A. Valeeva, Aleksandr I. Gusev
Summary: The investigation of coarse-crystalline powders of nonstoichiometric niobium carbide NbCy reveals that the particles are monocrystalline and possess anisotropy of elastic properties. The study evaluates the changes of elastic constants c(ij) in the homogeneity interval of nonstoichiometric niobium carbide from NbC0.70 to NbC1.00 for the first time. It is found that the elastic stiffness constants cij decrease as the composition of disordered NbCy deviates from stoichiometry, leading to a reduction in elastic anisotropy.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2021)
Article
Physics, Multidisciplinary
S. I. Sadovnikov, A. I. Gusev
Summary: The structure of Ag2S/ZnS nanoheterostructures was analyzed based on the morphology and elastic properties of Ag2S and ZnS sulfide single crystal particles. The arrangement of S atoms in (111) planes of cubic argentite beta-Ag2S and sphalerite ZnS was considered. Elastic stiffness constants of cubic argentite and sphalerite at a temperature of 300 K were estimated, showing that the formation of Ag2S/ZnS heterostructures with the interface formed by the (111) planes of cubic sphalerite ZnS and argentite beta-Ag2S is the most probable. The calculated universal criterion of the anisotropy of the elastic properties revealed that the studied cubic silver and zinc sulfides are elastically anisotropic.
Article
Chemistry, Physical
Maxim G. Kostenko, Jingyu Li, Zhi Zeng, Yongsheng Zhang, Sergey V. Sharf, Aleksandr I. Gusev, Alexey V. Lukoyanov
Summary: In this study, a theoretical search for ordered phases in hafnium carbide was conducted using the evolutionary algorithm USPEX for crystal structure prediction. Multiple thermodynamically stable and near-equilibrium compounds were identified. It was found that ordered vacancies do not deteriorate the mechanical properties of hafnium carbide, and ordered phases with vacancy concentrations less than 16.7% exhibit higher hardness compared to defect-free HfC.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Engineering, Electrical & Electronic
Igor Razzhivin, Aleksey Suvorov, Mikhail Andreev, Aleksandr Gusev
Summary: This article discusses the stability of electric power systems, focusing on small-disturbance rotor angle stability and a method for validating simulation results. The authors used numerical integration methods and various simulation tools for modeling, and demonstrated the feasibility of the proposed approach through experimental studies.
PRZEGLAD ELEKTROTECHNICZNY
(2021)
Article
Chemistry, Physical
Aleksandr Gusev
Summary: In this study, changes in elastic constants c(ij) of nonstoichiometric disordered cubic titanium carbide within the homogeneity interval were evaluated for the first time using a semiempirical method. It was found that the elastic stiffness constants c(ij) of disordered TiCy decrease as the titanium carbide composition deviates from stoichiometry, and the Vickers hardness H-V of titanium carbide increases non-linearly with growing relative carbon content y.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Physics, Multidisciplinary
S. I. Sadovnikov, A. I. Gusev
Summary: The relative positions of atomic planes of low-temperature monoclinic acanthite alpha-Ag2S and high-temperature bcc argentite beta-Ag2S have been determined from X-ray and electron microscopy data. The reversible phase transition between beta-Ag2S and alpha-Ag2S is due to the distortion in the bcc S sublattice. The filling probabilities of sites in the metal sublattice differ between the two structures, leading to different distances between Ag atoms in the crystals.
Review
Chemistry, Multidisciplinary
Albina A. Valeeva, Andrey A. Rempel, Svetlana Rempel, Stanislav Sadovnikov, Aleksandr Gusev
Summary: The size of oxide, carbide and sulfide nanoparticles has a significant impact on their nonstoichiometry. Different materials exhibit varying degrees of nonstoichiometry at the nanoscale due to changes in chemical composition.
RUSSIAN CHEMICAL REVIEWS
(2021)
Article
Chemistry, Physical
S. I. Sadovnikov, A. I. Gusev
Summary: Measurements of the heat capacity of superionic silver sulfide indicate that nanocrystalline argentite has a higher heat capacity than coarse-crystalline argentite due to limitations of the phonon spectrum imposed by the small particle size. As temperature increases, the elastic characteristics of argentite decrease, leading to a reduction in elastic anisotropy.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Stanislav Sadovnikov, Aleksandr Gusev
