Determination of the thermal stresses in anisotropic shells of revolution

Using the relations of the improved model of layered anisotropic shells based on the straight line assumption taking account of the thermal compression over the thickness we obtain a resolvent system of equations for shells whose properties depend on temperature. We carry out a study of the stresses in a two-layer cylindrical shell formed by winding as a function of the winding angle. Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 35, 1992, pp. 82–85.     

2H NMR spectra of 2-(p-heptylbenzoyloxy)-5-(p-heptylbenzenazo)tropone. A new sigmatropic liquid crystal

Liquid crystals incorporating in their molecular framework a seven-membered ring are still relatively rare [1]. Recently the synthesis and thermal behaviour of a series of liquid crystal materials having a tropone moiety in their mesogenic core have been reported [2-4]. These mesogens, based on a 2-(acyloxy)tropone core structure, show intramolecular migration of the acyl substituents between the two oxygen atoms at C-1 and C-2, an effect already known for simple 2-(acyloxy)tropones in their isotropic solutions [5]. This migration involves a concerted [1, 9]-sigmatropic rearrangement [2]. This rearrangement could play a major role in determining the properties of the mesophases: it has been suggested in fact that, because of this rearrangement, the mesogenic molecules acquire a mean rod-like shape which can sustain the mesophase formation [2].     

Conversion estimates for gas-solid reactions: Improved estimates for irreversible systems

Solid conversion has been of much interest to research workers and the Cumulative Gas Concentration Method (CGCM) has been developed to provide bounds for the reactant solid in irreversible systems having power-law type kinetics. This CGCM is used in conjunction with the Pseudo-Steady-State (PSS) assumption and these bounds appear to be good under certain conditions and for long times.

In this work, the PSS condition is not assumed when deriving the bounds on the cumulative gas concentration and the effect of the inclusion of the transient part is analysed. A technique, based on an iterative scheme incorporating the CGCM, is developed to provide improved estimates for the reactant solid.     

Application of the variational-moment approach to problems of the theory of elasticity of shells

We consider a method of obtaining an approximate system of equations of elasticity theory for shells, based on representing the components of the stress tensor and the displacement vector as a sum of products of moment characteristics depending on the coordinates of the base surface of the shell and functions of the normal coordinate to the base surface.Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 33, 1991, pp. 56–59.     

Studies on solution cast perfluorocarbonsulfonic acid ionomers

The thermal properties of perfluorocarbonsulfonic acid ionomer films cast from solution and their temperature-dependent far infrared spectra have been investigated. In addition to the endotherms and spectral changes associated with the loss of solvent as the films were heated, a significant exotherm has been observed and assigned to the relaxation associated with rearrangements resulting in partially crystallized phases in insoluble thermally treated membranes. © 1993 John Wiley & Sons, Inc.     

Measurement of the spin and temperature dependence of ddµ molecule formation rate in solid and liquid deuterium

The ddµ molecule formation rate is experimentally measured for the two hyperfine states of the dµ-atom in the temperature range of 5–30 K. Results are consistent with a preliminary measurement by the TRIUMF group and contradict theoretical predictions. The work has been performed on the JINR phasotron (Dubna).     

Electron transfer at lanthanum endohedral fullerenes

The aim of this contribution is to study lanthanum containing fullerenes produced and treated under different conditions. The work was done using solid soot extract giving poorly resolved ESR spectra or separated lanthanofullerenes in solution showing well resolved ESR spectra. ESR experiments in connection with the mass spectrometry give information on the electronic states due to the electron transfer from the endohedral metal to the fullerene cage and the influence of oxygen on endohedral lanthanofullerene. The analysis of ESR spectra indicates the presence of up to nine octets of lanthanum containing fullerenes. These species have different stabilities. Furthermore, a very narrow single ESR line in the lanthanofullerene spectrum was detected having a linewidth ΔB=0.008 mT and ag-factor 2.0025. The electron transfer to the endohedral La@C₈₂ molecule studied by voltammetry and electrochemicalin situ ESR experiments is described. The interaction of the lanthanofullerene with oxygen in solution is also studied. In different solvents the influence of oxygen on line broadening in the ESR spectra of La@C₈₂ was observed.     

On the solvability of physically nonlinear problems of Thermoelasticity

We study the problem of existence and uniqueness of generalized solutions of nonlinear vector boundary-value problems arising in the physically nonlinear theory of thermoelasticity. We prove the convergence of iteration processes in the space W ¹ ₂.