Subjects -> ASTRONOMY (Total: 94 journals)
 Showing 1 - 46 of 46 Journals sorted alphabetically Advances in Astronomy       (Followers: 51) Annual Review of Astronomy and Astrophysics       (Followers: 39) Annual Review of Earth and Planetary Sciences       (Followers: 63) Artificial Satellites       (Followers: 23) Astrobiology       (Followers: 14) Astronomical & Astrophysical Transactions: The Journal of the Eurasian Astronomical Society       (Followers: 6) Astronomical Journal       (Followers: 8) Astronomical Review       (Followers: 4) Astronomische Nachrichten       (Followers: 4) Astronomy & Geophysics       (Followers: 48) Astronomy and Astrophysics       (Followers: 60) Astronomy and Astrophysics       (Followers: 32) Astronomy and Computing       (Followers: 2) Astronomy Letters       (Followers: 22) Astronomy Reports       (Followers: 15) Astronomy Studies Development       (Followers: 12) Astroparticle Physics       (Followers: 8) Astrophysical Bulletin       (Followers: 3) Astrophysical Journal       (Followers: 19) Astrophysical Journal Letters       (Followers: 14) Astrophysical Journal Supplement Series       (Followers: 14) Astrophysics       (Followers: 29) Astrophysics and Space Science       (Followers: 46) Astrophysics and Space Sciences Transactions (ASTRA)       (Followers: 56) Astropolitics: The International Journal of Space Politics & Policy       (Followers: 12) Celestial Mechanics and Dynamical Astronomy       (Followers: 11) Chinese Astronomy and Astrophysics       (Followers: 24) Colloid Journal       (Followers: 3) Comptes Rendus Physique       (Followers: 2) Computational Astrophysics and Cosmology       (Followers: 3) COSPAR Colloquia Series       (Followers: 11) Earth, Moon, and Planets       (Followers: 55) Earth, Planets and Space       (Followers: 74) EAS Publications Series       (Followers: 8) EPL Europhysics Letters       (Followers: 8) Experimental Astronomy       (Followers: 39) Expert Opinion on Astronomy and Astrophysics       (Followers: 7) Extreme Life, Biospeology & Astrobiology - International Journal of the Bioflux Society       (Followers: 6) Few-Body Systems       (Followers: 1) Foundations of Physics       (Followers: 41) Frontiers in Astronomy and Space Sciences       (Followers: 12) Galaxies       (Followers: 6) Globe, The       (Followers: 4) Gravitation and Cosmology       (Followers: 4) Icarus       (Followers: 75) International Journal of Advanced Astronomy       (Followers: 28) International Journal of Astrobiology       (Followers: 4) International Journal of Astronomy       (Followers: 19) International Journal of Astronomy and Astrophysics       (Followers: 29) International Journal of Satellite Communications Policy and Management       (Followers: 13) International Letters of Chemistry, Physics and Astronomy       (Followers: 12) ISRN Astronomy and Astrophysics       (Followers: 7) Journal for the History of Astronomy       (Followers: 19) Journal of Astrobiology & Outreach       (Followers: 3) Journal of Astronomical Instrumentation       (Followers: 3) Journal of Astronomical Telescopes, Instruments, and Systems       (Followers: 5) Journal of Astrophysics       (Followers: 26) Journal of Astrophysics and Astronomy       (Followers: 52) Journal of Atmospheric and Solar-Terrestrial Physics       (Followers: 199) Journal of Cosmology and Astroparticle Physics       (Followers: 38) Journal of Geophysical Research : Planets       (Followers: 178) Journal of Geophysical Research : Space Physics       (Followers: 178) Journal of High Energy Astrophysics       (Followers: 22) Kinematics and Physics of Celestial Bodies       (Followers: 10) KronoScope       (Followers: 1) Macalester Journal of Physics and Astronomy       (Followers: 4) MNASSA : Monthly Notes of the Astronomical Society of South Africa       (Followers: 1) Molecular Astrophysics       (Followers: 1) Monthly Notices of the Royal Astronomical Society       (Followers: 14) Monthly Notices of the Royal Astronomical Society : Letters Nature Astronomy       (Followers: 8) New Astronomy       (Followers: 27) New Astronomy Reviews       (Followers: 17) Nonlinear Dynamics       (Followers: 19) NRIAG Journal of Astronomy and Geophysics       (Followers: 5) Open Astronomy       (Followers: 2) Physics of the Dark Universe       (Followers: 4) Planetary and Space Science       (Followers: 101) Planetary Science       (Followers: 52) Proceedings of the International Astronomical Union       (Followers: 2) Publications of the Astronomical Society of Australia       (Followers: 2) Publications of the Astronomical Society of Japan       (Followers: 3) Publications of the Astronomical Society of the Pacific       (Followers: 4) Research & Reviews : Journal of Space Science & Technology       (Followers: 17) Research in Astronomy and Astrophysics       (Followers: 29) Revista Mexicana de Astronomía y Astrofísica       (Followers: 2) Science China Physics, Mechanics & Astronomy       (Followers: 4) Solar Physics       (Followers: 34) Solar System Research       (Followers: 14) Space Science International       (Followers: 192) Space Science Reviews       (Followers: 97) Space Weather       (Followers: 24) Transport and Aerospace Engineering       (Followers: 13) Universe       (Followers: 5)
Similar Journals
 Colloid JournalJournal Prestige (SJR): 0.345 Citation Impact (citeScore): 1Number of Followers: 3      Hybrid journal (It can contain Open Access articles) ISSN (Print) 1608-3067 - ISSN (Online) 1061-933X Published by Springer-Verlag  [2626 journals]
• Erratum to: The Study of the Dispersity of Gold Organosols with the Use of
Au–AOT Composite Films
• Abstract: erratum
PubDate: 2020-11-01

• Microsclerometry as Applied to Studying Rehbinder Effect. Review
• Abstract: Works devoted to studying the effect of active environments on damageability of surfaces of solid bodies and materials upon contact actions (Rehbinder effect) have been briefly reviewed. A novel procedure, which combines microscratching and electrochemical reduction of an active component on a studied material surface, has been described. This procedure enables one to simulate and study the liquid-metal embrittlement of the material in the absence of a liquid metal phase on its surface.
PubDate: 2020-11-01

• Calculation of Chemical Potential of a Molecule on the Basis of Radial
Distribution Functions
• Abstract: The work is devoted to the application of the Hill method for calculating the chemical potential of a molecule in the one-component homogeneous molecular system within computer simulations. This method is based on the double integration of molecular radial distribution functions, which depend on the additional parameter that controls the strength of interactions between the molecules. The results of calculating the chemical potential of the argon molecule by the Hill method are compared with our data obtained by two other methods: the Widom test-particle method and the extended ensemble method within the Wang–Landau algorithm.
PubDate: 2020-11-01

• Influence of Magnetic Field on Micropolar Fluid Flow in a Cylindrical Tube
Enclosing an Impermeable Core Coated with Porous Layer
• Abstract: In this research work, we have investigated the Stokesian flow of a micropolar fluid in a cylindrical tube enclosing an impermeable core coated with porous layer in the presence of magnetic field. The axis of the cylinder is taken along the direction of fluid flow and the uniform magnetic field is applied in the direction perpendicular to the axis of the cylinder. Using appropriate boundary conditions, fluid velocities, microrotational velocities and stresses are evaluated for corresponding fluid flow regions. Expressions for volumetric flow rate through the annulus and the filtration velocity are obtained. Graphs of linear velocities, microrotational velocities and flow rate for various values of different parameters are plotted and discussed.
PubDate: 2020-11-01

• Experimental Study of Transport Coefficients of Aqueous Suspensions of
Nanodiamonds
• Abstract: This article presents experimental data on the coefficients of viscosity and thermal and electrical conductivities, as well as the absorption spectra, of suspensions of ultradispersed diamonds. Suspensions of UDA-S and UDP-A detonation nanodiamond particles, as well as UDP-AG diamond–graphite powder, are used in the experiments. The concentration of nanodiamonds in distilled water is varied within a range of 0.5–5 wt %. It is shown that the technology of purification diamond powders from side products of their synthesis substantially affects the physicochemical properties of aqueous suspensions of these powders.
PubDate: 2020-11-01

• Diffusion Deposition of Nanoparticles in a Layer of Granules
• Abstract: The deposition of aerosol nanoparticles has been studied in a model granular filter composed of parallel monolayers of contacting spherical granules with a square packing, where each even monolayer is shifted in its plane relative to an odd layer by the granule radius in two directions normal to one another. The monolayers of the granules are oriented normal to an incident flow. The efficiencies of diffusion collection of point particles by the granules have been calculated as depending on the distance between the layers in the regime of a three-dimensional gas flow at small Reynolds numbers $$\operatorname{Re}$$ $$\ll$$ 1 within a Peclet number range of $${\text{Pe}}$$ = 102−104. The calculation results have agreed with the published data and the results of measuring the deposition of monodisperse nanoparticles from nitrogen and helium upon filtration through layers of monodisperse metal spheres. The possibility of using a layer of granules as a diffusion battery for measuring the sizes of aerosol particles has been discussed.
PubDate: 2020-11-01

• Effective Parameters of Charged Spherical Particles in 1 : 1 Electrolyte
Solutions
• Abstract: In scope of the Poisson–Boltzmann theory, the electrostatic potential profiles in the vicinity of spherical particles immersed in 1 : 1 electrolyte solutions have been precisely calculated. Using the data on the behavior of the profiles at large distances from the particle surface, effective surface potential $${{\psi }_{{{\text{eff}}}}},$$ and its limiting value $$\psi _{{{\text{eff}}}}^{{{\text{sat}}}},$$ to which it tends upon an infinite growth of the surface charge, have been determined for a wide range of model parameters (surface charge density, particle radius, and electrolyte concentration). A universal curve has been plotted to represent the dependence of $$\psi _{{{\text{eff}}}}^{{{\text{sat}}}}$$ on reduced particle radius κa (a is the radius and κ is the reciprocal Debye screening radius) and to evidently illustrate the existence of two known limiting laws of variations in the effective potential that corresponds to the saturation conditions. The energy criterion and the analysis of its sensitivity to the cutoff threshold have been employed to evaluate the thicknesses of the shells formed by immobilized counterions around the spherical particles. Dependences of the shell thickness on the surface charge density, particle radius, and 1 : 1 electrolyte concentration have been analyzed. It has been revealed that there is limiting thickness $$l_{{{\text{eff}}}}^{{{\text{sat}}}},$$ which is reached upon the infinite growth of the surface charge density. A universal κ $$l_{{{\text{eff}}}}^{{{\text{sat}}}}$$ (κa) curve is presented and compared with the $$\psi _{{{\text{eff}}}}^{{{\text{sat}}}}$$ (κa) curve.
PubDate: 2020-11-01

• Neural Network Based Modeling of Grain Boundary Complexions Localized in
Simple Symmetric Tilt Boundaries Σ3 (111) and Σ5 (210)
• Abstract: A method is proposed for the neural network based analysis of the existence and stability of grain boundary complexions formed at high-symmetry tilt boundaries Σ3 (111) and Σ5 (210) in a polycrystalline Ni(Bi) solid solution. This method is based on the use of reference interparticle interaction potentials constructed within the framework of the density functional theory in combination with the structural capabilities of an artificial two-level self-learning neural network. The absolute error in determining potential energy by the neurosystem analysis is 0.012 eV/atom. The values of the formation enthalpy of grain boundary complexions for Σ3 and Σ5 boundaries are in rather good agreement with the published results of simulating this system and experimental data.
PubDate: 2020-11-01

• Influence of the Structure of a Surface Layer of Methyl Methacrylate-Based
Cationic Particles on Adsorption of Biomolecules
• Abstract: Crosslinked cationic particles 200–600 nm in diameter have been synthesized via emulsifier-free copolymerization of methyl methacrylate and 2-aminoethyl methacrylate hydrochloride in the presence of cross-linking agents (N,N'-methylenebisacrylamide, triethylene glycol dimethacrylate, and diethylene glycol dimethacrylate). It has been shown that polymer particles with a maximum concentration of surface functional groups (1.42 µmol/m2) and a stable structure of a surface layer are formed only in the presence of ethanol (20 vol %). The synthesized particles efficiently adsorb biologically active substances, and their dispersions are stable against aggregation in buffer solutions at pH 7.0.
PubDate: 2020-11-01

• Light Diffraction in Magnetic Emulsions with High Interfacial Tension
• Abstract: Specific features of small-angle light scattering by aqueous magnetic emulsions under the action of a magnetic field and a hydrodynamic field of a rotating fluid have been investigated. It has been shown that the experimentally observed diffraction lines that have no pronounced maxima and minima are due to diffraction on an irregular system of droplet chains arising in the magnetic field. Under the combined action of the magnetic and hydrodynamic fields, a rotation of a diffraction line is observed. This phenomenon has been interpreted using the known models of orientation of extended particles having complex shapes. It has been shown that the experimental nonlinear dependence of the rotation angle of a droplet chain on the angular rate of fluid rotation may be explained by S-shaped deformations of a chain.
PubDate: 2020-11-01

• Specific Features of the Formation of Adsorption Layers from Products of
Mechanochemical Modification of Humic Acids at a Liquid–Gas Interface
• Abstract: Ethoxy- and aminoderivatives of natural polymers, humic acids, have been obtained via mechanochemical synthesis in a vibrational apparatus. The structure and physicochemical properties of their macromolecules have been studied by IR and UV spectroscopies. The average molecular mass of the products has been determined. The pendant drop shape and oscillating pendant drop methods have been employed to study the tensiometric and dilatational rheological characteristics of the surface layers formed at the interfaces between air and solutions of the modified derivatives of humic acids. It has been found that the formation of the adsorption layers of humic acid salts agrees with the protein adsorption model, which takes into account the possible existence of n states of macromolecules and their ability to aggregation in the surface layers when using the relations of the model in a semiempirical form. It has been shown that the viscoelasticity moduli of the surface layers of the ethoxylated derivatives of humic acids are increased relative to that of their unmodified form. Aminoderivatives of humic acids exhibit a higher stability in an acidic medium due to the presence of amino groups.
PubDate: 2020-11-01

• High-Density Carbon Adsorbents for Natural Gas Storage
• Abstract: Physicochemical regularities are studied for the synthesis of molded active carbons based on coconut shells and peat, with a latex emulsion and a carboxymethyl cellulose (CMC) sodium salt solution being used as binding agents. The materials are obtained at compacting pressures of 25, 50, and 100 MPa. The specific surface areas of the composite samples obtained from peat and coconut shells are SBET ≈ 1320 and ≈1290 m2/g, respectively. The specific micropore volumes of the composites based on peat and coconut shells are W0 = 0.50 and 0.45 cm3/g, respectively. Latex-modified carbon samples have a higher bulk density than those molded with CMC. The molding of the active carbons is accompanied by partial degradation of their porous structure. The Dubinin theory of volume filling of micropores (TVFM) has been employed to calculate the values of adsorption and active specific capacity of the molded adsorbents with respect to methane at a temperature of 273 K and a pressure of up to 100 bar. The experimental and calculated data have shown that the active capacity of the new microporous carbon composite materials may be as large as 180 m3 (NTP)/m3, when the pressure drops from 100 to 1 bar. It has been concluded that it is reasonable to employ the TVFM for preliminary calculations of the parameters of adsorption systems used for natural gas storage.
PubDate: 2020-11-01

• Gold Nanorods with Organosilica Shells as a Platform for Creating
Multifunctional Nanostructures
• Abstract: The perspectives of using γ-mercaptopropyltrimethoxysilane as a precursor for creating multifunctional composite nanoparticles (CNPs) with a rodlike gold core and an organosilica shell have been analyzed. It is shown that the presence of thiol groups, which are capable of specific interactions with metal ions and atoms, in the shell makes it possible to “directly” (i.e., without any additional modification) load rather large amounts of an anticancer drug, cisplatin, into it. In addition, preliminary data have been obtained that indicate the possibility of nitrosation of the SH-groups of the shells, which is very important from the viewpoint of creating container CNPs for NO, with such containers providing not only its delivery to tumors, but also its controlled release under the action of laser radiation.
PubDate: 2020-11-01

• Laser Desorption and Ionization of Thiosemicarbazides
• Abstract: Ionized products of desorption of thiosemicarbazides from a steel target surface before and after deposition of solid solutions of thiosemicarbazides in organic matrices (nicotinic acid, α-cyano-4-hydroxycinnamic acid, 2,5-dihydroxybenzoic acid, and dithranol) onto it have been studied by mass spectrometry. 2,5-Dihydroxybenzoic acid has been revealed to be a universal matrix for studying the synthesized thiosemicarbazides under the conditions of matrix-assisted laser desorption/ionization. Its use leads to a 100-fold decrease in the detection limit of thiosemicarbazides as compared with α-cyano-4-hydroxycinnamic acid. Investigations of the decomposition of metastable protonated thiosemicarbazide molecules accelerated in the ion-source region have resulted in suggesting the mechanisms of their fragmentation and ionization.
PubDate: 2020-11-01

• Adsorption of Boron from a Simulated Soil Solution Using Zn–Al and
Mn-Doped Zn–Al Layered Double Hydroxides
• Abstract: Three types of layered double hydroxides (LDHs) including Zn–Al and Mn-doped Zn–Al LDHs with Mn 2 and 10 mol % respect to Zn content (Zn–Al, Zn–Mn1–Al and Zn–Mn2–Al, respectively) were prepared. The effect of various parameters such as time, boron concentration, pH, temperature, ionic strength and competing anions were investigated to compare the efficacy of synthesized LDHs for boron adsorption in a simulated soil solution. The results suggest that the adsorption capacity of B is enhanced by incorporation of Mn in the Zn–Al LDH. The highest adsorption was observed for Zn–Mn2–Al probably due to its higher specific surface area as well as due to the ion exchange mechanism in combination with surface adsorption. The kinetics of boron adsorption on the LDHs followed a pseudo-second order model. The isotherm data of Zn–Al was matched with Langmuir model while the sorption data for Zn–Mn1–Al and Zn–Mn2–Al were described by both Langmuir and Freundlich models. Although boron adsorption slightly increased with increasing pH from 5 to 9, it decreases at pH > 9 because of the competition of OH– groups and change in LDH surface charge at pH > pHZPC. The negative values of $$\Delta H_{{\text{r}}}^{{\text{o}}}$$ showed that adsorption of boron was exothermic in nature. The presence of competing anions interfere boron adsorption. Moreover, an increase of electrolyte concentration led to a decrease of boron adsorbed on the LDHs. It seems that Zn–Mn2–Al could be used as an effective sorbent for boron adsorption in soil solution, as it indicated the highest affinity to boron even at high pH and ionic strength conditions.
PubDate: 2020-11-01

• Effect of Reductant (Chitosan) Molecular Mass on the Synthesis of Silver
Nanoparticle Dispersions and the Properties of Ring Deposits Resulting
from Evaporation of Droplets of These Dispersions
• Abstract: A comparative analysis has been performed for silver nanoparticle dispersions obtained by the chemical reduction of Ag+ ions using several samples of chitosan with different molecular masses as reductants and stabilizers. The structure and conductivity of ring deposits resulting from the evaporation of droplets of the obtained dispersion have been studied. It has been shown that the average size of silver nanoparticles, their number concentration, and the degree of precursor reduction weakly depend on chitosan molecular mass, while the geometric parameters and electrical conductivity of the ring deposits substantially change upon the passage from oligochitosans to high-molecular-mass chitosan.
PubDate: 2020-11-01

• Continuous Flow Synthesis of Iron Oxide Nanoparticles Using Water-in-Oil
Microemulsion
• Abstract: A continuous laminar flow reactor for the synthesis of nanopowder in microemulsion is described. The reactor is suitable for separated handling with nucleation, growth, and stabilization processes. The synthesis of iron oxide nanoparticles was selected as a model case. A water−sodium dodecyl sulphate−cyclohexene system was used as the microemulsion system for dissolving reactive aqueous solution, precursor, and a particle stabilizer. The product was purified and transferred to the aqueous phase. The result was a colloid solution of iron oxide nanoparticles in water of 50–200 nm in size with a zeta potential ranging from –25 to –57 mV. The product was characterized by UV-VIS spectroscopy, powder XRD, dynamic light scattering, electron microscopy, and electron diffraction. The results showed that water-in-oil microemulsion method is useful for the synthesis of nanopowders to obtain large amounts of stable product.
PubDate: 2020-11-01

• Effect of the Stability of Highly Concentrated Emulsions Containing
Styrene–Divinylbenzene Mixtures on the Structure of Highly Porous
Copolymers Formed on Their Basis
• Abstract: Highly porous polymer materials with preset pore sizes and porosities can be prepared via polymerization of dispersion media of highly concentrated water-in-oil emulsions. In this work, the effect of divinylbenzene concentration in styrene–divinylbenzene mixed dispersion media of highly concentrated emulsions on the emulsion stability and the structure of resulting polymer materials has been investigated. It has been found that the emulsion stability at 25 and 65°C decreases with an increase in divinylbenzene concentration. Therewith, the pore size in the polymer material slightly grows from 4.0 to 4.5 μm. Emulsion stability expectedly rises with the concentration of a surfactant (Span 80). It has been shown that concentrations of divinylbenzene and Span 80 equal to 10 vol % are optimal for obtaining highly porous polymers from emulsions containing ammonium peroxodisulfate as a polymerization initiator. When emulsions containing benzoyl peroxide as a polymerization initiator are used to obtain highly porous polymers, NaCl (0.02–0.03 wt %) should be added to the dispersed phase of the emulsions. In this case, emulsion stability increases due to a decrease in the Ostwald ripening rate. Accordingly, highly porous polymers with smaller pores are obtained.
PubDate: 2020-11-01

• Stability of the Supersaturated State of Encapsulated Solutions
• Abstract: By the example of highly concentrated water-in-oil emulsions, in which droplets of a supersaturated aqueous ammonium nitrate solution are dispersed in industrial oil, it has been shown that a thermodynamically stable state is possible due to the limited volume of dispersed phase particles.
PubDate: 2020-09-01

• Comprehensive Understanding of Gold Nanoparticles Enhancing Catalytic
Efficiency
• Abstract: — Enzymes play significant roles in both life and industry, and increasing enzymatic activity has been a long-term goal of the biochemical science. Recently, it has been reported that nanomaterials can enhance both the specificity and yield of polymerase chain reaction (PCR) though the mechanism of this enhancement remained unclear. By using gold nanoparticles (AuNPs) as model nanomaterials and the cellulase as a typical enzyme, we studied whether and how nanomaterials affect enzymatic activities investigating various aspects of the reaction process. The results showed that the catalytic efficiency of cellulase depends on the concentration of AuNPs. By detailed studying the relation between catalysis and experimental conditions, we found that the enzymatic activity can be increased up to 13.13% upon adding AuNPs in concentration of 0.5 nM into the reaction solution. The optimal pH, temperature, and incubation time for cellulose with 0.5 nM AuNPs were found to be same as those for the cellulose alone. These findings might be useful for enhancing enzymatic activities in the industrial processes.
PubDate: 2020-09-01

JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762