Brans-Dicke static universes

We study flat and nonflat static models obeying the Brans-Dicke theory and RW metric, including the case which considers Bertolami's time-dependent cosmological term. We find several solutions where the density remains constant, while the gravitational constant varies with time.     

1-Methyl-3-alkyl-2(3H)imidazolethione Complexes of Metal Halides: A Thematic-Ligand Approach to Involve Undergraduates in Research Projects

A method that we have used to attract undergraduates into research projects incorporates a thematicligand approach using a class of thiourea-type ligands known as 1-methyl-3-alkyl-2(3H)-imidazolethiones (^mait) to make new metal and nonmetal halide addition products never before reported in the literature. A related selenium analog and a bidentate thione are also employed in the process, which to date has produced 24 new compounds. Twenty-one student co-authors, 10 female and 11 male, have been involved in the presentation of these results in a total of 15 published in peer-reviewed journals and in 13 presentations at regional, national, or international symposia. The students start the work as a team research project in an intermediate inorganic synthesis laboratory course by first making the ligand and then its addition product which is characterized by standard methods during the course. Many of the attempts are failures, but teams that produce new compounds often go on to research projects that result in further structural characterization through collaborative efforts with the Georgia Institute of Technology or with Clemson University. A case study involving the synthesis and characterization of 1-methyl-3-(2-propyl)-imidazole-2(3H)-thione (mipit) and its bismuth trichloride adduct, BiCl₃ (mipit)₂ is presented in this report.     

A simple procedure for deriving an electrical double layer equation from the Born—Green—Yvon theory

A simple procedure for deriving electrical double layer equations from electrolyte theories is applied to the Born—Green—Yvon equation. It is shown that when the auto-field effects are not considered in the wall-ion potential, the equation obtained with this procedure leads to gross inconsistencies.     

Effect of crystallization temperature on the crystalline phase content and morphology of poly(vinylidene fluoride)

The effect of temperature on the crystallization of α, β, and γ phases of PVDF from dimethylacetamide (DMA) solution was studied. Variation in the crystallinity content of these three phases was obtained as a function of temperature using infrared spectroscopy, differential scanning calorimetry (DSC) and x-ray diffraction techniques. Such variation is related to the dependence of the crystallization rate of each phase with temperature, and allowed a better understanding of some results found in the literature about the crystallization and interconversion of these phases. Micrographs of samples present morphologies that corroborate with the proposed explanations. © 1994 John Wiley & Sons, Inc.     

A new reaction: lead(IV) acetate-mediated oxidative fragmentation of homoallylic alcohols

Treatment of a homoallylic alcohol with lead(IV) acetate in refluxing benzene for 2 hours results in an oxidative cleavage to give a carbonyl compound and an allylic acetate with high yield.     

Citation for the 2003 ICMI Felix Klein medal to Guy Brousseau

Information

Citation for the 2003 ICMI Felix Klein medal to Guy Brousseau     

Abundance of stable ergodicity

We consider the set of volume preserving partially hyperbolic diffeomorphisms on a compact manifold having 1-dimensional center bundle. We show that the volume measure is ergodic, and even Bernoulli, for any C ² diffeomorphism in an open and dense subset of This solves a conjecture of Pugh and Shub, in this setting.     

Existence and decay rate estimates for the wave equation with nonlinear boundary damping and source term

The wave equation with a source term is considered