The Representation of Electrical Conductances for Polyvalent Electrolytes by the Quint–Viallard Conductivity Equation

Electrical conductivities of dilute aqueous solutions of lithium, sodium, potassium, cesium, rubidium and ammonium sulfates were determined and analyzed in terms of partially associated electrolytes of the 1:2 type. The conductivities reported here were determined from 15 to 35 °C and are compared with available literature results. Representation of conductances, in a framework of the ion association model, was performed using the Quint–Viallard conductivity equation and the Debye–Hückel expression for activity coefficients. However, the equilibrium constants were considered as adjustable parameters. Specific conductivities in concentrated aqueous solutions of sulfates were fitted to a new empirical equation with only three adjustable parameters. These parameters at constant temperature are much easier to determine from experimental conductivities than the corresponding four parameters in the usually applied Casteel and Amis conductivity equation.     

The Synthesis,Characterization and DC Electrical Conductivity of Polypyrrole‐Zirconium Complex

Polypyrrole‐zirconium complex has been synthesized by reacting 2‐amino‐3,4‐dicyano‐5‐mercaptopyrrole with zirconium nitrate in absolute ethanol under reflux for 24 h. The product has been characterized by elemental analyses, FTIR spectroscopy, in addition to thermal analysis (TGA and DSC) and its solubility has been investigated. The DC electrical conductivity variation of polypyrrole‐zirconium complex has been studied in the temperature range 300–500 K after annealing for 24 h at 100°C and doping with I₂, FeCl₃ and CuCl₂ · H₂O for comparison. An attempt has been made to interpret the DC electrical conductivity behavior and thermal properties to chain length, dopant used, polymer structure and attached groups.     

Structure of Electrical Double Layer on Liquid Pb–Ga Alloy in Aqueous Electrolytes

A new electrode, which is a liquid Pb–Ga alloy (0.06 at. % Pb), is developed and studied. It is shown that the alloy's double-layer characteristics dramatically differ from characteristics of a Ga electrode and are practically identical to characteristics of a Pb electrode. Hence, the Pb–Ga electrode in fact models electrochemical properties of a liquid Pb electrode. It is established that the metallic capacitance of the Pb–Ga electrode occupies an intermediate position between values of metallic capacitance of Ga and Hg electrodes, provided the metal–water chemisorption interaction is absent and the electrode charge is fixed. Hydrophilicity of the Pb–Ga electrode is substantially lower than hydrophilicity of a Ga electrode and coincides with hydrophilicity of an Hg electrode. It is shown that In–Ga, Cd–Ga, and Pb–Ga electrodes have close values of the electrochemical work function, and the chemisorption potential drop of the solvent in them increases in the series Pb–Ga < In–Ga < Cd–Ga with decreasing distance of closest approach of water molecules to the ionic core of the metal. The absorbability of anions at the Pb–Ga electrode increases in the series BF^– ₄= SO^2– ₄< Cl^–< Br^–< I^–.     

Conductivity and Morphology of Composite Solid Electrolytes SnO2· nH2O–Heteropolycompounds

The structure and surface characteristics of SnO₂ · 1.5H₂O and composite materials with heteropolycompounds (HPC) formulated as SnO₂ · 1.5H₂O–HPC (where HPC = (NH₄)₃PW₁₂O₄₀ · nH₂O, (NH₄)₂HPW₁₂O₄₀ · nH₂O, and H₃PW₁₂O₄₀ · nH₂O) are studied by scanning tunneling microscopy. Hydrated tin oxide is characterized by a globular structure which differs substantially from the morphology of composite materials. The conductivity is studied as a function of both the temperature and humidity of environment and the composition of composite materials. For composite materials containing ((NH₄)₂HPW₁₂O₄₀ · nH₂O, the conductivity is shown to vary monotonously with the composition and obey the mixture rule. Introduction of (NH₄)₃PW₁₂O₄₀ · nH₂O to a composite is found to cause an extremely fast conductivity decay, whereas addition of H₃PW₁₂O₄₀ · nH₂O results in the appearance of a plateau on the conductivity vs. composition curve. The explanation given to the phenomena observed is based on the mechanism of protonic transport in heteropolycompounds.     

Electrical Conductivity and Decomposition Potentials of the LiAsF6 Solutions in the Propylene Carbonate–N,N-Dimethylformamide Mixed Solvent

Russian Journal of Electrochemistry - The electrical conductivity of LiAsF6 solutions in a propylene carbonate–N,N-dimethylformamide mixed solvent is measured at temperatures of 253.15,...     

Synthesis and Ionic Conductivity of Network Polymer Electrolytes with Internal Plasticizers

Network polymer electrolytes with free oligo(oxyethylene) chains as internal plasticizers were prepared by cross-linking poly(ethylene glycol) acrylates. The effects of salt concentration and properties of internal plasticizers on ionic conductivity were studied.     

The Wittig–Horner reaction for the synthesis of neratinib

The Wittig–Horner reaction is a classic method to get alkenes by reaction phosphonates with carbonyl compounds. In this study, it was used for the synthesis of the anticancer drug neratinib. In this method, ethyl diethoxyphosphinylacetate and dimethylaminoacetaldehyde diethylacetal, replacing (E)-4-(dimethylamino)but-2-enoyl acid hydrochloride and oxalyl chloride, were used to synthesize the 6-position side chain of neratinib.     

The application of selected radionuclides for monitoring of the D–D reactions produced by dense plasma-focus device

The dense plasma focus (DPF) device—DPF-1000U which is operated at the Institute of Plasma Physics and Laser Microfusion is the largest that type plasma experiment in the world. The plasma that is formed in large plasma experiments is characterized by vast numbers of parameters. All of them need to be monitored. A neutron activation method occupies a high position among others plasma diagnostic methods. The above method is off-line, remote, and an integrated one. The plasma which has enough temperature to bring about nuclear fusion reactions is always a strong source of neutrons that leave the reactions area and take along energy and important information on plasma parameters and properties as well. Silver as activated material is used as an effective way of neutrons measurement, especially when they are emitted in the form of short pulses like as it happens from the plasma produced in Dense Plasma-Focus devices. Other elements such as beryllium and yttrium are newly introduced and currently tested at the Institute of Plasma Physics and Laser Microfusion to use them in suitable activation neutron detectors. Some specially designed massive indium samples have been recently adopted for angular neutrons distribution measurements (vertical and horizontal) and have been used in the recent plasma experiment conducted on the DPF-1000U device. This choice was substantiated by relatively long half-lives of the neutron induced isotopes and the threshold character of the ¹¹⁵In(n,n′)^115mIn nuclear reaction.     

Tensile,Electrical Conductivity,and Morphological Properties of Carbon Black–Filled Epoxy Composites

This work investigates the effect of carbon black content on the tensile, electrical, and morphological properties of epoxy matrix. Carbon black–filled epoxy composites were obtained by mixing the desired amount of carbon black from bamboo stem (BS-CB), oil palm empty fruit bunch (EFB-CB), and coconut shell (CNS-CB) with the epoxy resin. Tensile and electrical properties of carbon black from three different sources (BS-CB, EFB-CB, and CNS-CB) used to fill epoxy composite with 5% filler loading were measured and the results indicated improvement in tensile and electrical properties. The diffraction patterns of X-ray diffraction (XRD) indicated nonlinear crystalline amorphous structure of the CB.     

A Study of the Emulsified Microemulsion by SAXS,Cryo‐TEM,SD‐NMR,and Electrical Conductivity

A water‐in‐oil microemulsion was further dispersed in an aqueous phase containing Pluronic F127 as a steric stabilizer, to form a specific type of double emulsion termed emulsified microemulsion (EME). The inner microemulsion phase was made from glycerol‐monooleate (GMO), R(+)‐limonene, ethanol and glycerol. SAXS (small x‐ray scattering), PGSE‐NMR (pulse gradient spin echo‐NMR), electrical conductivity, and cryo‐TEM (cryogenic‐transmission electron microscopy) imaging techniques were used to confirm the existence of inner W/O nano‐droplets after second emulsification step and upon EME aging. Spherical globules of EME without long‐range internal order were observed by the SAXS measurements and the cryo‐TEM images. The average globule size of about 200–300 nm remained intact for at least 6 months.     

Amorphization of Metal–Organic Framework MOF-5 by Electrical Discharge

Amorphization of various solid materials has attracted increasing attentions. We report here an amorphization of metal–organic framework-5 (MOF-5) of composition Zn₄O(BDC)₃ (BDC = 1,4-benzenedicarboxylate) using dielectric-barrier discharge (DBD) treatment at ambient pressure and low gas temperature (around 120°C). The irreversible amorphization was confirmed by x-ray diffraction (XRD) characterization. The result of N₂ adsorption–desorption measurements revealed a collapse of pores, which further supported the XRD results. The destroying of part of carboxylate groups might be the main reason resulting in the amorphization of MOF-5.     

Equation of state for Lennard–Jones flexible ring fluids

We present a new equation of state for Lennard–Jones (LJ) flexible ring fluids. We perform Monte-Carlo simulations for freely-jointed Lennard–Jones chain fluids (3-, 6- and 8-mer) in the canonical ensemble and obtain the intramolecular end-to-end pair correlation function data under extensive density and temperature conditions. We correlate these as a function of the density, the temperature and the number of segments in a chain. We apply this function to thermodynamic perturbation theory (TPT) and obtain a new equation of state for Lennard–Jones flexible ring fluids. We also compare existing simulation data [J. Chem. Phys. 104 (1996) 1729] with the results obtained using the newly derived equation of state.     

Conductivity studies of the molecular encapsulation of sodium perfluoroctanoate byβ-cyclodextrin derivatives

The molecular encapsulation of sodium perfluoroctanoate (SPFO) by hydroxypropyl--cyclodextrin (HP--CD) or 2,6-di-O-methyl--cyclodextrin (DM--CD) has been analyzed by measuring the conductivity in solution of the ternary systems formed by CD + SPFO + H₂O. The studies were carried out at 25 °C using a fully computerized electrical conductivity technique. The measurements were made as a function of CD concentration at various non-micellar concentrations of SPFO, and as a function of CD and SPFO concentrations with [CD]/[SPFO] constant at stoichiometric ratio. The inclusion complexes, HP--CD-SPFO and DM--CD-SPFO, were characterized through the stoichiometry, which has been found to be 1 : 1 in both cases, and the binding constants, which have been evaluated from the conductivity data with a model proposed by us considering the variation of the ionic molar conductivities with the concentration and the association of the surfactant counterion to the inclusion complex. The resultingK values indicate that the interaction between the CD cavity and the monomeric SPFO is strong and similar in both cases.     

The Enhancement of the Formation of Wells–Dawson-Type Polyoxometalates by the Addition of High Concentrations of LiCl

Wells–Dawson-type polyoxometalates are formed by heating an acidic Mo(VI) or W(VI) solution containing significantly higher concentrations of hetero ions, P(V) or As(V), than the ideal molar ratio [M]/[X] = 1/9 (M = Mo, W; X = P, As). Most of the phosphate and arsenate remains unreacted in the reaction mixture. These reaction conditions are unusual, even though more reagents than the stoichiometric amounts are frequently needed to obtain complete reactions. In the present study, the replacement of a large amount of unreacted hetero ions containing salts by normal ions (salts) was investigated. The formation of Wells–Dawson-type polyoxometalates, [X₂M₁₈O₆₂]^6? (X = P, As; M = Mo, W), in the presence of LiCl and NaCl was investigated by Raman spectroscopy and ³¹P NMR in aqueous solution. The addition of LiCl enhanced the formation of Wells–Dawson-type polyoxometalates, which formed under solution conditions close to the ideal molar ratio [M]/[X] = 1/9.     

Correlation Analysis of the Fluorescence Data of Some Benzaldehyde Derivatives by the Dual-Parameter Equation

Ithasbeenrecentlyestablishedthattherearefourcategoriesofpossiblecircumstancesforcorrelati0nanalyses0fradicalreactivitiesandspectralpropertiesbyEq.(l),Eq.(2)andEq.(3)."(I)Bothp0larandspin-del0calisationeffectsaretwortant,O.2l.O.(III)Thespin-delocalizationeffectspredominate,lpmdpJJ'I<0.2.(IV)Nocorrelationcanbeachieved.Wehavef0undthatthebehavi0roffluorescencespectraldataofsomestyrenes,'bycorrelati0nanalysiswiththedual-parameterEq.(…     

A Modified Phase-Fitted Runge–Kutta Method for the Numerical Solution of the Schrödinger Equation

A modified phase-fitted Runge–Kutta method (i.e., a method with phase-lag of order infinity) for the numerical solution of periodic initial-value problems is constructed in this paper. This new modified method is based on the Runge–Kutta fifth algebraic order method of Dormand and Prince [33]. The numerical results indicate that this new method is more efficient for the numerical solution of periodic initial-value problems than the well known Runge–Kutta method of Dormand and Prince [33] with algebraic order five.     

The calculation of the optimum pH range for synthesizing BST nanopowders by sol–gel auto-combustion process

The optimum pH range for synthesizing barium strontium titanate (Ba_0.5Sr_0.5TiO₃, BST) nanopowders by sol–gel auto-combustion method was calculated based on the principles of matter balance and charge balance. The effectiveness of the calculation was proved by the successful synthesis of highly dispersive, spherically shaped and pure BST nanoparticles with setting the pH in the range pre-decided by theoretical evaluation. Ours might have provided an effective path for pre-deciding the solution pH in synthesizing various oxide nanopowders by sol–gel auto-combustion method.     

New Approach to Justification of the Williams–Landel–Ferry Equation

A derivation of the Williams–Landel–Ferry equation for the temperature dependence of relaxation time τ(T) in the glass transition range is proposed. This derivation is of a general character and is not related to any particular form of the functional dependence τ(T), in contrast to the known approaches. The modification of the Williams–Landel–Ferry equation and examples of its practical applications are considered.     

The preparation of samples for α-counting by the direct evaporation of organic solutions

A method is described for the preparation of thin deposits of α-emitting elements by evaporation of solutions in organic solvents. By heating the periphery of the tray, a suitable temperature gradient is maintained across the tray, giving smooth evaporation of the solvent to leave a deposit which is suitable for α-counting. It has been shown that on a semi-routine basis, the method is rapid and gives good precision.     

The study of the speciation of uranyl–sulphate complexes by UV–Vis absorption spectra decomposition

Uranyl–sulphate complexes are the predominant U(VI) species present in acid solutions resulting either from underground uranium ore leaching or from the remediation of leaching sites. Thus, the study of U(VI) speciation in these solutions is of practical significance. The spectra of UO₂(NO₃)₂ + Na₂SO₄ solutions of different Φ _S = [SO₄²⁻]/[U(VI)] ratio at pH = 2 were recorded for this purpose. As the presence of uranyl-nitrate complexes should be expected under these experimental conditions, the spectra of UO₂(NO₃)₂ + NaNO₃ solutions with different Φ _N = [NO₃⁻]/[U(VI)] ratio at pH = 2 were also measured. The effects of Φ _S and Φ _N ratios value were most pronounced in wavelength interval 380–500 nm. Therefore, these parts of experimental overall spectra were used for deconvolution into the spectra of individual species by the method proposed. It enabled to calculate stability constants of anticipated species at zero ionic strength. The Specific Ion Interaction Theory (SIT) was used for this purpose. Stability constants of UO₂SO₄, UO₂(SO₄)₂²⁻, UO₂NO₃ ⁺ and UO₂(NO₃)₂ coincided well with published data, but those for UO₂(SO₄)₃⁴⁻ and UO₂(NO₃)₃⁻ were significantly lower.