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  Subjects -> PHYSICS (Total: 745 journals)
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    - MECHANICS (20 journals)
    - NUCLEAR PHYSICS (44 journals)
    - OPTICS (86 journals)
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PHYSICS (542 journals)                  1 2 3 4 5 6 | Last

Acta Acustica united with Acustica     Full-text available via subscription   (Followers: 7)
Acta Mechanica     Hybrid Journal   (Followers: 15)
Advanced Composite Materials     Hybrid Journal   (Followers: 14)
Advanced Functional Materials     Hybrid Journal   (Followers: 34)
Advanced Materials     Hybrid Journal   (Followers: 341)
Advances in Condensed Matter Physics     Open Access   (Followers: 6)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 3)
Advances in Geophysics     Full-text available via subscription   (Followers: 4)
Advances in High Energy Physics     Open Access   (Followers: 12)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 1)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 13)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 14)
Advances in OptoElectronics     Open Access   (Followers: 3)
Advances In Physics     Hybrid Journal   (Followers: 7)
Advances in Physics Theories and Applications     Open Access   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 8)
Advances in Synchrotron Radiation     Hybrid Journal   (Followers: 1)
AIP Advances     Open Access   (Followers: 4)
AIP Conference Proceedings     Full-text available via subscription   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Condensed Matter Physics     Open Access   (Followers: 2)
American Journal of Signal Processing     Open Access   (Followers: 8)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 1)
Annalen der Physik     Hybrid Journal   (Followers: 2)
Annales Geophysicae (ANGEO)     Open Access   (Followers: 3)
Annales Henri PoincarĂ©     Hybrid Journal   (Followers: 2)
Annales UMCS, Physica     Open Access  
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 3)
Annals of Physics     Hybrid Journal   (Followers: 2)
Annals of West University of Timisoara - Physics     Open Access  
Annual Reports on NMR Spectroscopy     Full-text available via subscription   (Followers: 1)
Annual Review of Analytical Chemistry     Full-text available via subscription   (Followers: 9)
Annual Review of Condensed Matter Physics     Full-text available via subscription   (Followers: 1)
Annual Review of Materials Research     Full-text available via subscription   (Followers: 4)
APL Materials     Open Access   (Followers: 4)
Applied Composite Materials     Hybrid Journal   (Followers: 9)
Applied Physics A     Hybrid Journal   (Followers: 9)
Applied Physics Frontier     Open Access   (Followers: 1)
Applied Physics Letters     Hybrid Journal   (Followers: 25)
Applied Physics Research     Open Access   (Followers: 6)
Applied Physics Reviews     Hybrid Journal   (Followers: 7)
Applied Radiation and Isotopes     Hybrid Journal   (Followers: 5)
Applied Remote Sensing Journal     Open Access   (Followers: 9)
Applied Spectroscopy     Full-text available via subscription   (Followers: 12)
Applied Spectroscopy Reviews     Hybrid Journal   (Followers: 2)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (Followers: 3)
Astronomy & Geophysics     Hybrid Journal   (Followers: 1)
Astrophysical Journal Letters     Full-text available via subscription   (Followers: 3)
Astrophysical Journal Supplement Series     Full-text available via subscription   (Followers: 3)
Atoms     Open Access  
Attention, Perception & Psychophysics     Full-text available via subscription   (Followers: 6)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Axioms     Open Access  
Bangladesh Journal of Medical Physics     Open Access  
Bauphysik     Hybrid Journal   (Followers: 1)
Biomaterials     Hybrid Journal   (Followers: 30)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 15)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 12)
Biomedical Imaging and Intervention Journal     Open Access   (Followers: 5)
Biophysical Reviews     Hybrid Journal  
Biophysical Reviews and Letters     Hybrid Journal   (Followers: 3)
BMC Biophysics     Open Access   (Followers: 7)
BMC Nuclear Medicine     Open Access   (Followers: 5)
Brazilian Journal of Physics     Hybrid Journal  
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Bulletin of Materials Science     Open Access   (Followers: 39)
Bulletin of the Atomic Scientists     Full-text available via subscription   (Followers: 4)
Bulletin of the Lebedev Physics Institute     Hybrid Journal   (Followers: 1)
Bulletin of the Russian Academy of Sciences: Physics     Hybrid Journal  
Caderno Brasileiro de Ensino de FĂ­sica     Open Access  
Canadian Journal of Physics     Full-text available via subscription   (Followers: 1)
Cells     Open Access   (Followers: 1)
Central European Journal of Physics     Hybrid Journal   (Followers: 1)
CERN courier. International journal of high energy physics     Free  
Chinese Journal of Astronomy and Astrophysics     Full-text available via subscription   (Followers: 1)
Chinese Journal of Chemical Physics     Hybrid Journal   (Followers: 1)
Chinese Physics B     Full-text available via subscription  
Chinese Physics C     Full-text available via subscription  
Chinese Physics Letters     Full-text available via subscription  
Cohesion and Structure     Full-text available via subscription   (Followers: 2)
Colloid Journal     Hybrid Journal   (Followers: 2)
Communications in Mathematical Physics     Hybrid Journal   (Followers: 2)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 3)
Communications in Theoretical Physics     Full-text available via subscription   (Followers: 1)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 48)
Composites Part B : Engineering     Hybrid Journal   (Followers: 63)
Computational Materials Science     Hybrid Journal   (Followers: 18)
Computational Mathematics and Mathematical Physics     Hybrid Journal   (Followers: 1)
Computational Particle Mechanics     Hybrid Journal  
Computational Science and Discovery     Full-text available via subscription  
Computer Physics Communications     Hybrid Journal  
Contemporary Concepts of Condensed Matter Science     Full-text available via subscription  
Contemporary Physics     Hybrid Journal   (Followers: 10)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 3)
Contributions to Plasma Physics     Hybrid Journal   (Followers: 2)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 1)
Cryogenics     Hybrid Journal   (Followers: 14)
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Diamond and Related Materials     Hybrid Journal   (Followers: 12)
Differential Equations and Nonlinear Mechanics     Open Access   (Followers: 4)

        1 2 3 4 5 6 | Last

Journal Cover Colloid Journal
   Journal TOC RSS feeds Export to Zotero [4 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1608-3067 - ISSN (Online) 1061-933X
     Published by Springer-Verlag Homepage  [2209 journals]   [SJR: 0.207]   [H-I: 18]
  • Preparation and characterization of biosurfactant based on hydrophobically
           modified alginate
    • Abstract: Abstract Hydrophobic modified alginate (HM-alginate) was synthesized using a low-energy, environment-friendly process in aqueous solution, with sodium alginate and dodecyl glycidyl ether as starting materials. The HM-alginate was characterized using 1H NMR, and the reaction efficiency was about 40%. The HM-alginate aggregated in solution; the critical micelle concentration (CMC) was determined using surface tension and dynamic light scattering methods. We observed reasonable agreement between the CMC values obtained by the different techniques, and the CMC was 4.0 × 10−4 g/mL. The zeta-potential of the HM-alginate in aqueous solution was about −82 mV, which is higher than −51 mV of the sodium alginate. Rheology measurements showed that the HM-alginate solution exhibits a Newtonian behavior at all shear rates, whereas the apparent viscosity is very low. The solubility of the liposoluble substance Sudan IV increased significantly with HM-alginate concentration. This result is promising for potential applications of HM-alginate as an ecology-safe material to encapsulate lipophilic substances.
      PubDate: 2014-09-01
       
  • Electrokinetic potential of multilayer carbon nanotubes in aqueous
           solutions of electrolytes and surfactants
    • Abstract: Abstract The effect of electrolytes with single-, double- and triple-charged counterions, as well as cationic (cetyltrimethylammonium bromide) and anionic (sodium dodecyl sulfate) surfactants, on the electrokinetic potential of multiwall carbon nanotubes prepared via catalytic pyrolysis of propylene in a gas phase according to the CCVD technology has been studied. It has been shown that the influence of different electrolytes on the electrophoretic mobility of the nanotubes does not differ essentially from their effect on the behavior of well-studied inorganic dispersed particles; i.e., the dependence of the absolute values of the ζ-potential on the concentration of a 1: 1 electrolyte passes through a maximum and the introduction of double-charged counterions dramatically reduces the ζ-potential, while the addition of triple-charged cations and a cationic surfactant causes charge reversal of the nanotube surface. The adsorption of sodium dodecyl sulfate in a neutral medium increases the negative ζ values; this effect evens out in the presence of an alkali due to a rise in the electrostatic repulsion between surfactant anions and nanotube surface, which bears a high negative charge resulting from the dissociation of surface functional groups.
      PubDate: 2014-09-01
       
  • The formation of submonolayer thorium coatings on a silicon oxide surface
           by electrochemical deposition
    • Abstract: Abstract Data are reported on the mechanisms of the formation of submonolayer coatings based on thorium oxide on the surface of Si(111) single crystal with natural oxide as a result of electrochemical deposition. It is experimentally shown that the deposition of thorium atoms from an acetone solution of Th(NO3)4 onto the surface of natural silicon oxide leads to the formation of defects in the thin silicon oxide layer, which is accompanied by the deposition of thorium nanoclusters onto a pure silicon surface. The observed effects have been qualitatively explained assuming the breakdown of natural silicon oxide due to the presence of an electrical double layer in the near-surface region of the cathode.
      PubDate: 2014-09-01
       
  • Preparation of palladium nanoparticles with desired sizes in aqueous
           solutions
    • Abstract: Abstract Methods have been developed for obtaining palladium nanoparticles with near-spherical shape and desired and controlled sizes from 2 to 50 nm via reduction of metal ions in aqueous solutions. The influence of sodium polyphosphate and sodium polyacrylate used as stabilizing agents on the sizes and aggregation and sedimentation stability of the particles has been revealed. The dependence of nanoparticle sizes on the initial concentration of palladium(II) ions has been established.
      PubDate: 2014-09-01
       
  • Aggregates of poly-functional amphiphilic molecules in water and oil
           phases
    • Abstract: Abstract The solvation and aggregate formation of complex amphiphilic molecules such as tetra-acids in polar and nonpolar phases are studied via Molecular Dynamics simulations. The nonpolar core of tetra-acid molecules is found to be effectively impermeable for water molecules resulting in a low solubility in the polar solvent, while nonpolar solvent molecules sufficiently solvate the amphiphilic molecules considered, enabling an open conformation of their molecular structure. The rigidity of the core region of the tetra-acid molecules has been found to play a crucial role in their behavior in both polar and nonpolar phases. In the polar phase, simulations have shown that tetra-acids form micelle-like structures with a small aggregation number, confirming previous experimental work. The identification of a case of study in which micelle-like structures can form only with a small aggregation number enables the study via Molecular Dynamics of micelle-micelle interactions. Micelle stability and dispersion in the polar phase under different conditions can be therefore investigated. In the nonpolar phase, the preferential interactions between carboxyl groups, the affinity of the tetra-acids with the solvent molecules, and the structural characteristics of the central core moiety of the tetra-acids have been found to possibly induce a web like array, or network.
      PubDate: 2014-09-01
       
  • Heterocoagulation of polysaccharide-coated platinum nanoparticles with
           ovarian-cancer cells
    • Abstract: Abstract Platinum nanoparticles coated with adsorption layers of polysaccharides of Chlorella vulgaris (PtPS) have been synthesized and their heterocoagulation with human ovarian-cancer cells of the A2780 line has been studied. It has been shown that the characteristic time of the aggregation of the cells with PtPS nanoparticles is 20–25 min, which corresponds to fast barrierless coagulation. The cytotoxic effect of PtPS nanoparticles reaches saturation and more than 50% of the cells die within this time period. Cytomorphological investigations have shown that A2780 cells with doubled resistance to an antitumoral antibiotic, doxorubicin, are more sensitive to the toxic action of PtPS nanoparticles than nonresistant cells are. An electrokinetic control test has been proposed for cancer-cell resistance based on the measurement of variations in the ζ-potential of nanoparticles due to adsorption of water-soluble metabolites of the cells on a particle surface.
      PubDate: 2014-09-01
       
  • Polyelectrolyte-surfactant association—from fundamentals to
           applications
    • Abstract: Abstract Mixed polymer-surfactant systems have broad applications, ranging from detergents, paints, pharmaceutical, and cosmetic to biotechnological. A review of the underlying polymer-surfactant association in bulk is given. While ionic surfactants bind broadly to polymers, nonionics only do so if the polymer has a lower polarity and can interact by hydrophobic interactions. Water-soluble polymers, which have hydrophobic groups, form physical cross-links, hence they may be used as thickeners. The rheological behaviour is strongly influenced by various cosolutes; especially strong effects are due to surfactants and both a decrease and an increase in viscosity can occur. When the polymer-surfactant interactions are particularly strong, an associative phase separation can occur, like in the case where there is electrostatic attraction as well as hydrophobic; this and other types of phase separation phenomena are described. Except for linear ionic and nonionic polymers, the interactions between surfactants and cross-linked polymers, microgel particles and covalent macroscopic gels are analyzed, as well as the possibility of forming gel particles of interest for encapsulation purposes. Furthermore, the behavior of these mixed systems on surfaces is discussed. In particular, we consider the adsorption of mixtures of ionic polymers and oppositely charged surfactants on polar and nonpolar surfaces. Depending on concentration, an ionic surfactant can either induce additional polyion adsorption or induce desorption. Kinetic control of adsorption and, in particular, desorption is typical. Important consequences of this include an increased adsorption on rinsing and path dependent adsorbed layers. Recently, considerable attention has been given to the interaction between DNA and cationic surfactant, both as a means to understand the behaviour of DNA in biological systems and to develop novel formulations, for example for gene therapy. Here we review aspects such as DNA compaction, DNA covalent gels and DNA soft nanoparticles.
      PubDate: 2014-09-01
       
  • An asymmetric slit: Pressure on larger wall
    • Abstract: Abstract Local normal components of pressure tensor have been compared for the walls of a plane-parallel slit between a cylinder face and a planar surface. It has been shown that the normal pressure on the infinite surface is nonzero even outside of the slit. The correction for the finite size of the slit to the local normal pressure is more noticeable on this surface than on the surface of the cylinder.
      PubDate: 2014-09-01
       
  • Evaporation of droplets of silver nanoparticle dispersions on metal
           surfaces
    • Abstract: Abstract The formation of ring-shaped deposits during the evaporation of droplets of silver nanoparticle dispersions on aluminum, copper, and nickel substrates has been studied, and the geometric characteristics and conductivity of the deposits have been determined. The formation process of the deposits on the above substrates has been shown to exhibit some peculiarities to compare with that on hydrophilic glass substrates. These peculiarities lead to substantial differences in the geometric parameters and structure of the deposits formed on substrates of different natures. Therewith, the qualitative regularities of variations in the geometric parameters and conductivity of the deposits with the size (numerical concentration) of silver nanoparticles remain preserved.
      PubDate: 2014-09-01
       
  • Palladium nanoparticles in aqueous solution: Preparation, properties, and
           effect of their size on catalytic activity
    • Abstract: Abstract A method has been developed for the preparation of palladium nanoparticles with different sizes of up to 7 nm via the reduction of Pd(II) ions with hydrogen in an aqueous solution on seed metal nanoparticles (2.5 nm). The effect of the size of nanoparticles on their catalytic activity in methyl viologen reduction with molecular hydrogen in an alkaline medium has been studied. It has been found that the specific catalytic activity of palladium nanoparticles is independent of their size.
      PubDate: 2014-09-01
       
  • Theoretical study of interdiffusion of aqueous solutions of 1 : 1
           electrolytes having the same anion through a cation-exchange membrane
    • Abstract: Abstract The interdiffusion of aqueous 1: 1 electrolytes having the same anion through a negatively charged (cation-exchange) membrane has been studied without taking into account the diffusive layers. It has been established that the interdiffusion coefficients of the cations depend (in addition to their own diffusion coefficients in the membrane) on the ratio of the diffusion coefficients of both cations to the diffusion coefficient of the anion and the ratio of the density of charges fixed in the membrane to the equal concentration of the electrolytes on both sides of the membrane, as well as the equilibrium distribution coefficients of cationanion ion pairs in the membrane matrix. The conditions have been found under which the membrane plays the role of a “blocking system” (like a diode) that is impenetrable to cations located on both sides of the membranes in spite of the existence of their concentration gradients. The developed approach can be used to describe the interdiffusion of 1: 1 electrolytes through any uniformly charged membrane.
      PubDate: 2014-09-01
       
  • On the evolution of a multicomponent droplet during nonisothermal
           diffusion growth or evaporation
    • Abstract: Abstract A set of equations has been derived for the size, composition, and temperature of a multicomponent droplet of a nonideal solution during its diffusion nonisothermal condensation growth or evaporation in a multicomponent mixture of vapors with an incondensable carrier gas. In addition to complete equations for material and heat transfer in the vapor-gas medium surrounding the droplet, the derived set, in the general case, describes the nonstationary growth or evaporation of the droplet under arbitrary initial conditions (initial size and temperature of the droplet and the concentrations of the nonideal multicomponent solution in it) and the establishment of the stationary values of the composition, temperature, and the rate of variations in the size of the droplet with allowance for heat effects and diffusion and thermodiffusion material transfer, Stefan flux, motion of the droplet surface, and the nonideality of the solution in the droplet. A simplified set of equations obtained without taking into account the contributions from the flow, cross effects, and thermal expansion in the equations of the material and heat transfer in the vapor-gas medium has been considered. Equations describing growth/evaporation in the stationary regime have been analyzed for droplets of ideal multicomponent solutions.
      PubDate: 2014-09-01
       
  • Zinc phthalocyanine-based water-soluble thiolated photosensitizer and its
           conjugates with gold nanoparticles: Synthesis and spectral properties
    • Abstract: Abstract A new photosensitizer, monoconjugate of zinc octa-4,5-carboxy-phthalocyanine with L-cysteine, which is rather readily soluble in water, has been synthesized and characterized. The chemisorption of its molecules on the surface of gold nanoparticles with different sizes has been studied. A comparative analysis of the spectral characteristics of the synthesized conjugates of gold nanoparticles with the photosensitizer has shown that the photosensitizer grafted to gold nanoparticles exhibits rather intense fluorescence. Therefore, such conjugates can be used for photodynamic therapy of tumors.
      PubDate: 2014-09-01
       
  • Formation and properties of hydrophobic CeO       class="a-plus-plus">2 nanoparticles
    • Abstract: Abstract Uniform hydrophobic cerium oxide (CeO2) nanoparticles in a cubic structure with an average size of 4.6 nm were obtained by a novel oil-water interface method in the presence of 0.40 M NaOH. Effects of reactants concentration, oxidation reaction temperature, and the type of surfactants on the final products were investigated. The products were characterized by X-ray diffraction, transmission electron microscopy, UV-visible spectroscopy, room-temperature photoluminescence spectroscopy and contact angle measurements. The products exhibited high luminescence and strong hydrophobicity. The data suggest that Ce(OH) x 4−x (x < 4) is a precursor complex for the formation of CeO2 nanoparticles in liquid phase and its concentration controls the size of CeO2 particles. The adsorption of the surfactant influences the formation of the hydrophobic particles of CeO2 by the oil-water interface method.
      PubDate: 2014-09-01
       
  • Ion-isotopic exchange reaction kinetics using organic base anion exchange
           resins Indion-102 and Indion GS-400
    • Abstract: Abstract The present study deals with the kinetic study of iodide and bromide ion-isotopic exchange reactions in organic based anion exchange resins Indion-102 (nuclear grade) and Indion GS-400 (non-nuclear grade) using radiotracer isotopes. The resins in iodide and bromide form were equilibrated respectively with iodide and bromide ion solutions which were previously spiked with 131I and 82Br radiotracer isotopes. For both bromide and iodide ion-isotopic exchange reactions, it was observed that the values of specific reaction rate increase with increase in ion concentration from 0.001 to 0.004 M at a constant temperature of 40.0°C. However, at constant ion concentration of 0.003 M, the specific reaction rate was observed to decrease with rise in temperature from 30.0 to 45.0°C. Also it was observed that for iodide ion-isotopic exchange reaction by using Indion-102 resin, the values of specific reaction rate, amount of iodide ion exchanged, initial rate of iodide ion exchange and logK d were 0.258 min−1, 0.492 mmol, 0.127 mmol/min and 19.2, respectively, which were higher than 0.208 min−1, 0.416 mmol, 0.087 mmol/min and 17.6, respectively, obtained by using Indion GS-400 resin under identical experimental conditions of 40.0°C, 1.000 g of ion exchange resin and 0.003M labeled iodide ion solution. The same trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate that, under identical experimental conditions, Indion-102 resin shows higher performance than Indion GS-400 resin.
      PubDate: 2014-09-01
       
  • Sorption of the antitumor drug prospidinum on microgels of polysaccharide
           phosphates
    • Abstract: Abstract The intermolecular interaction of prospidinum with gel-forming dextran and starch phosphates has been studied. The sorption equilibria have been studied for cytostatic and the biodegradable hydrogels of polysaccharide phosphates. The concentration coefficients of ion exchange equilibrium and distribution coefficients of prospidinum have been calculated at different degrees of microgel phase filling with the cytostatic, and the relations between the coefficients and the degree of hydrogel swelling have been determined. The ion-exchange and nonexchange contributions to sorption values have been found. The analysis of the distribution coefficients has demonstrated that the concentration of prospidinum sorbed through the nonexchange mechanism is higher than its concentration in an external solution due to the van der Waals interactions between prospidinum cations and macromolecules of polysaccharide phosphates. The Na form of polysaccharide phosphates is the optimal carrier for prospidinum, because this form has a higher density of the total negative charge than their H form has.
      PubDate: 2014-09-01
       
  • Disjoining pressure in a symmetric circular slit
    • Abstract: Abstract Local disjoining pressure has been calculated for dispersion forces inside a symmetric circular plane-parallel empty slit. In contrast to the asymmetric case, the local disjoining pressure in a symmetric slit is defined unambiguously. The edge effects in the symmetric slit have been shown to be substantially stronger than those in the asymmetric one. The data obtained have been compared with the published results of the approximate calculation of averaged disjoining pressure. The approximate approach has been revealed to underestimate the absolute value of the correction to the averaged disjoining pressure by nearly 10%.
      PubDate: 2014-09-01
       
  • Colloido-chemical characteristics of porous glasses with different
           compositions in KNO3
           solutions. 1. Structural and electrokinetic characteristics of membranes
    • Abstract: Abstract The structural (specific surface area, liquid-filtration coefficient, average pore radius, volume porosity, and structural-resistance coefficient) and electrokinetic (counterion transport numbers, specific electrical conductivity, and electrokinetic potential) characteristics of porous glasses with different compositions have been determined in potassium nitrate solutions with concentrations of 10−3–10−1 M. All the membranes under investigation have been shown to exhibit the dependences of efficiency coefficients and counterion transport numbers on electrolyte concentration and pore size that are predicted by the theory of an electrical double layer. It has been established that, at a constant electrolyte concentration, the absolute values of electrokinetic potential increase with the average pore radius because of variations in the slipping-plane position.
      PubDate: 2014-09-01
       
  • The effect of input pulse duration on the elution curve profile
    • Abstract: Abstract Numerical simulation and new analytical solutions have been used to study the effect of the duration of the input pulse of an adsorbate on the development of the elution curve profile in the adsorption dynamics. Elution curves calculated with regard to finite input pulse duration have been compared with those determined for the instantaneous injection of an adsorbate in the absence of extracolumn broadening. Quantitative regularities of variations in curve parameters measured as the time corresponding to the maximum of the curve and its width at a fixed height as depending on the length of an adsorbent layer have been estimated. The influence of the input pulse duration on the statistical moments of the elution curve has been determined, with the obtained moments being in agreement with the published solution that was previously found using the Laplace transformations. Correspondence between the theoretical and experimental data has been revealed for argon elution from a helium flowing through an activated carbon layer.
      PubDate: 2014-07-01
       
  • Dispersity and stability of foams obtained from poly(vinyl alcohol)
           solution and the properties of resulting foamed cryogels
    • Abstract: Abstract Foams have been generated from aqueous poly(vinyl alcohol) solution by two different methods: dispersion (mechanical) method, i.e., by bubbling a gas through a porous medium into the aqueous poly(vinyl alcohol) solution, and the condensation (chemical) method, i.e., by performing a gas-generating reaction directly in the polymer solution. The effect of the formation method on foam stability and dispersity has been studied. The foam produced by the condensation method of foaming the aqueous poly(vinyl alcohol) solution with nitrogen is more stable and finely dispersed and has a higher expansion ratio than that obtained by bubbling the gas through the polymer solution. Foamed cryogels have been formed by freezing-thawing the foam resulting from the chemical reaction in the polymer solution. The values of the elasticity modulus, melting temperature, and thermal conductivity of the cryogels have been determined.
      PubDate: 2014-07-01
       
 
 
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