Electrochemical generation of hypohalogenite ions and its application to determining pharmaceuticals

The optimum conditions for the electrochemical generation of hypohalogenite ions (current efficiency, actual redox potentials, and pH ranges) in the coulometric titration of sulfanilamide preparations, acid hydrazides and amides, amino acids, and sulfur-containing pharmaceuticals are determined. © 1997 MAEe Cyrillic signK Hayκa/Interperiodica Publishing

Study of Convergence and Divergence of EAEU Integration Processes Based on the Gini Index

Regionalization and participation at the integration associations represent a typical way of national economic development. To be inside an integration process allows member states to address better their socio-economic problems and political coordination. The stability and resilience of integration associations are critical to their success. In this optic the integration associations may be subjects convergence and divergence. These phenomena may be envisaged in the income inequality of the participating countries.Aim. To study the features and prospects of the socio-economic convergence within the EEU member states, the EEU strategic contour and within the main trends of integration processes in Eurasia.Task. The tasks are following. The first one is to study the sustainability of the EEU and within its strategic contours formed by agreements on free trade zones through the convergent and divergent trends assessment. The second task is to conduct a comparative analysis of Eurasian integration to the European Union and ASEAN development.Methods. Assess the level and dynamics of income inequality among the EEU states and samples of states with which the EEU has agreements on free trade zones, which are the CIS, Serbia, Vietnam, Iran and Singapore, as well as states with which such agreements are planned to be concluded in the near future. This list of the EEU’s prospect partners includes Egypt, Israel and India, based on the Gini index, using the European Union and ASEAN as reference parameters. Use calculations to interpret the processes of convergence and divergence of various types of integration processes.Results. The estimates showed, in general, a significant interpretive potential of the interstate Gini index. The study particular results demonstrated that the EEU has a level of convergence comparable to the level of the EU before the accession of a large array of states in 2004. The level of convergence of the CIS, estimated using the Gini index, is comparable to the current level of the European Union. It was also revealed that both in the EU and in the CIS, the reduction in inequality over the selected analysis interval does not have a clear prospect. Calculations also showed the convergence of states within the EEU and its strategic contours to be sensitive to external shocks, while the convergence of ASEAN states is more directed.Conclusions. The approach used by the authors to assess the convergence of integration processes based on the calculation of the interstate Gini index explains with sufficient completeness the reasons for the successful development of the EEU and its sustainability. At the same time, the use of the interstate Gini index for the analysis of convergence and divergence of integration processes made it possible to conclude that the integration models of the states of the Global North and the Global South are diverse

Casimir Effects Near the Big Rip Singularity in Viscous Cosmology

Analytical properties of the scalar expansion in the cosmic fluid are investigated, especially near the future singularity, when the fluid possesses a constant bulk viscosity \zeta. In addition, we assume that there is a Casimir-induced term in the fluid's energy-momentum tensor, in such a way that the Casimir contributions to the energy density and pressure are both proportional to 1/a^4, 'a' being the scale factor. A series expansion is worked out for the scalar expansion under the condition that the Casimir influence is small. Close to the Big Rip singularity the Casimir term has however to fade away and we obtain the same singular behavior for the scalar expansion, the scale factor, and the energy density, as in the Casimir-free viscous case.Comment: 7 pages RevTeX, no figures. Minor changes in discussion, some references added. To appear in Gen. Rel. Gra

Synthesis and tribological properties of new fluoro-containing oligomers

Oligomers based on (polyfluoroalkyl)methyl oxiranes and thiiranes was first synthesized by the cationic polymerization in the presence of boron trifluoride etherate. Molecular weights of the products were defined by cryoscopic method. It was found that synthesized oligomers can be used as additives to industrial lubricants and sulfur oligomers are of the greatest positive tribological effect. © Pleiades Publishing, Ltd., 2013

The susceptibility and excitation spectrum of (VO)2_2P2_2O7_7 in ladder and dimer chain models

We present numerical results for the magnetic susceptibility of a Heisenberg antiferromagnetic spin ladder, as a function of temperature and the spin-spin interaction strengths $J_\perp$ and $J_{||}$. These are contrasted with new bulk limit results for the dimer chain. A fit to the experimental susceptibility of the candidate spin-ladder compound vanadyl pyrophosphate, (VO)$_2$P$_2$O$_7$, gives the parameters $J_\perp = 7.82$ meV and $J_{||} = 7.76$ meV. With these values we predict a singlet-triplet energy gap of $E_{gap} = 3.9$ meV, and give a numerical estimate of the ladder triplet dispersion relation $\omega(k)$. In contrast, a fit to the dimer chain model leads to $J_1=11.11$ meV and $J_2=8.02$ meV, which predicts a gap of $E_{gap} = 4.9$ meV.Comment: 16 pages, 6 figures available upon request, RevTex 3.0, preprint ORNL-CCIP-94-04 / RAL-94-02

Viscous Dark Cosmology with Account of Quantum Effects

The analytic properties of the energy density rho(t) of the cosmic fluid, and the Hubble parameter H(t), are investigated near to the future singularity t=t_s assuming different forms for the equation of state. First, it is shown that the inclusion of quantum effects coming from the conformal anomaly modifies the singularity. Thereafter, we consider the effect coming from a bulk viscosity in the fluid. The viscosity tends to reduce the magnitude of t_s, but does not alter the singularity itself (the exponent). Main emphasis is laid on the simple case when the equation of state is p=w*rho, with w a constant.Comment: 10 pages, no figures; to appear in Eur. Phys. J.

Inelastic Neutron Scattering from the Spin Ladder Compound (VO)2P2O7

We present results from an inelastic neutron scattering experiment on the candidate Heisenberg spin ladder vanadyl pyrophosphate, (VO)2P2O7. We find evidence for a spin-wave excitation gap of $E_{gap} = 3.7\pm 0.2$ meV, at a band minimum near $Q=0.8 A^{-1}$. This is consistent with expectations for triplet spin waves in (VO)2P2O7 in the spin-ladder model, and is to our knowledge the first confirmation in nature of a Heisenberg antiferromagnetic spin ladder.Comment: 11 pages and 2 figures (available as hard copy or postscript files from the authors, send request to [email protected] or [email protected]), TEX using jnl, reforder and eqnorder, ORNL-CCIP-94-05 / RAL-94-04

Substituted benzaldehydes in the darzens condensation with alkyl dihaloacetates

The Darzens reaction of dihaloacetic acid esters with aromatic aldehydes produces either arylhaloglycidic or arylhalopyruvic esters depending on the nature of the substituent in the aromatic ring. Alkyl p- methoxyphenylchloropyruvates undergo spontaneous intermolecular cyclocondensation to form pyranone or furanone derivatives depending on the character of the alkyl fragment. © 2006 Springer Science+Business Media, Inc

Dark Energy Fluid with Time-Dependent, Inhomogeneous Equation of State

The four-dimensional Friedman flat universe, filled with an ideal fluid with a linear (oscillating) inhomogeneous equation of state (EoS) depending on time, is studied. The equations of motion are solved. It is shown that in some cases there appears a quasi-periodic universe, which repeats the cycles of phantom-type space acceleration. The appearance of future singularities resulting from various choices for the input parameters is discussed.Comment: 9 pages pdf, 4 figures. To appear in European Physical Journal

Viscous Fluids and Gauss-Bonnet Modified Gravity

We study effects of cosmic fluids on finite-time future singularities in modified $f(R,G)$-gravity, where $R$ and $G$ are the Ricci scalar and the Gauss-Bonnet invariant, respectively. We consider the fluid equation of state in the general form, $\omega=\omega(\rho)$, and we suppose the existence of a bulk viscosity. We investigate quintessence region ($\omega>-1$) and phantom region ($\omega<-1$) and the possibility to change or avoid the singularities in $f(R,G)$-gravity. Finally, we study the inclusion of quantum effects in large curvatures regime.Comment: 14 page