The influence of aluminum on the thermal decomposition of hexabromocyclododecane

The influence of aluminum on the thermal stability of hexabromocyclododecane (HBCD) was investigated. HBCD pyrolysis was carried out using thermogravimetric analyzers and a laboratory scale reactor. The identification of decomposition products was based on FTIR and gas-chromatographic/mass-spectrometric techniques. The results obtained confirmed that the presence of aluminum caused a lower thermal stability of HBCD. However, the presence of aluminum also resulted in a significant increase of the char yield and caused the shift towards an exothermic decomposition process. The analysis of the decomposition products showed that the presence of aluminum triggers polycondensation reactions during HBCD thermal degradation.     

Impedance spectroscopy of reactive polymers. 2. Multifunctional epoxy/amine formulations

Dielectric measurements were utilized to follow the advancement of cure in a bifunctional and a tetrafunctional epoxy/amine formulation. In deferance to earlier dielectric studies of cure, complex impedance was measured and used to calculate ionic resistivity. By using complex impedance we were able to separate, according to their frequency dependence, the contributions to overall polarization from electrode blocking layers, mobile charge carriers, and dipole relaxations. At any stage of cure, there is a unique frequency at which ionic resistivity can be singularly measured. Our approach does not involve trial-and-error frequency search, it measures dielectric response in real time, and is conducive to the development of phenomenological models based on equivalent circuits. Values of ionic resistivity measured at different cure time and temperature were used to quantify the progress of cure. Excellent agreement was reported between the calculated values of normalized degree of cure obtained by dielectric and calorimetric measurements. It was suggested that apart from the extrinsic conductivity by ionic impurities, an intrinsic mechanism which involves the reactive molecules contributes to the overall ionic conductivity. © 1995 John Wiley & Sons, Inc.     

A vectorizable potential energy functional for reactive scattering

Critical steps in trajectory programs for vector restructuring are analysed. The crucial effect of potential energy routine design on the efficiency of trajectory calculations performed on supercomputers have been investigated using a test program for which time consumptions when different algorithms are implemented are compared. Comparisons have been extended to more realistic computational situations by inserting related routines in a trajectory program and calculating reactive properties of some systems of chemical interest.This paper was presented at the International Conference on The Impact of Supercomputers on Chemistry, held at the University of London, London, UK, 13–16 April 1987     

Polysingular integral operators

Summary We study a class of linear singular integral operators of the Cauchy type on the n-torus; an application is given to a boundary value problem for functions of several complex variables.     

Weak differentiability of BV functions on stratified groups

We prove the almost everywhere approximate differentiability of functions with bounded variation in stratified groups and we study their approximate discontinuity set. We introduce functions of bounded higher order variation and obtain a weak version of Alexandroff differentiability theorem in this context. We present a nontrivial class of functions with second order bounded variation, arising from inf-convolution formula of a suitable ``cost' function.