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The purpose of the investigation was to replicate and extend a study by Jensen and Munro which found reaction time (RT) and movement time (MT) parameters to correlate negatively and moderately with Raven matrices performance. A sample of 20 ninth-grade girls was used. Relationships between RT and MT and Raven scores were found to be negative and moderate to… (More)
Let L n be a collection of n unknotted, unlinked circles in 3-space, and let PΣ n be the group of motions of L n where each circle ends up back at its original position. This group was introduced in the PhD thesis of David Dahm, a student of Ralph Fox, and was later studied by various authors, notably Deborah Goldsmith. Alan Brownstein and Ronnie Lee… (More)
The pure symmetric automorphism group of a finitely generated free group consists of those automorphisms which send each standard generator to a conjugate of itself. We prove that these groups are duality groups.
We give an explicit formula for the cohomology of a right angled Artin group with group ring coefficients in terms of the cohomology of its defining flag complex.
A combinatorial summation identity over the lattice of labelled hy-pertrees is established that allows one to gain concrete information on the Euler characteristics of various automorphism groups of free products of groups. In particular, we establish formulae for the Euler characteristics of: the group of Whitehead automorphisms Wh(* n i=1 G i) when the G… (More)
The prerequisite for widespread use of hydrogen as an energy carrier is the development of new materials that can safely store it at high gravimetric and volumetric densities. Metal borohydrides M(BH 4) n (n is the valence of metal M), in particular, have high hydrogen density, and are therefore regarded as one such potential hydrogen storage material. For… (More)
Metal hydrides can be utilized for hydrogen storage and for thermal energy storage (TES) applications. By using TES with solar technologies, heat can be stored from sun energy to be used later, which enables continuous power generation. We are developing a TES technology based on a dual-bed metal hydride system, which has a high-temperature (HT) metal… (More)
A novel species of metal amidoborane ammoniate, [Al(NH2BH3)6 3− ][Al(NH3)6 3+ ] has been successfully synthesized in up to 95% via the one-step reaction of AlH3·OEt2 with liquid NH3BH3·nNH3 (n = 1~6) at 0 °C. This solution based reaction method provides an alternative pathway to the traditional mechano-chemical ball milling methods, avoiding possible… (More)
Magnesium borohydride (Mg(BH4)2) is one of the most promising hydrogen storage materials. Its kinetics of hydrogen desorption, reversibility, and complex reaction pathways during decomposition and rehydrogenation, however, present a challenge, which has been often addressed by using transition metal compounds as additives. In this work the decomposition of… (More)
A cost effective catalyst is of great importance for consideration of MgH 2 as potential hydrogen storage material. In this regard, we investigated the catalytic role of alkaline metal fluoride on the hydrogen storage behavior of MgH 2. Samples were synthesized by admixing 5 mol % MgF 2 into MgH 2 powder using planetary ball mill. Hydrogenation measurements… (More)