Ab-initio investigation of phonon dispersion and anomalies in palladium

In recent years, palladium has proven to be a crucial component for devices ranging from nanotube field effect transistors to advanced hydrogen storage devices. In this work, I examine the phonon dispersion of fcc Pd using first principle calculations based on density functional perturbation theory. While several groups in the past have studied the acoustic properties of palladium, this is the first study to reproduce the phonon dispersion and associated anomaly with high accuracy and no adjustable parameters. In particular, I focus on the Kohn anomaly in the [110] direction.Comment: 19 pages, preprint format, 7 figures, added new figures and discussio

Lyapunov exponents in Minkowskian U(1) gauge theory

U(1) gauge fields are decomposed into a monopole and photon part across the phase transition from the confinement to the Coulomb phase. We analyze the leading Lyapunov exponents of such gauge field configurations on the lattice which are initialized by quantum Monte Carlo simulations. We observe that the monopole field carries the same Lyapunov exponent as the original U(1) field. Evidence is found that monopole fields stay chaotic in the continuum whereas the photon fields are regular.Comment: Lattice2002(topology), 3 pages, 4 figure

Boron Fertilization of Corn in Kentucky

The need for use of boron (B) for alfalfa production has been recognized for many years in Kentucky and is presently recommended for general use as an annual topdressing on alfalfa fields. Use of B is also recommended in Kentucky for red clover fields which are to be harvested for seed. In recent years, there has been interest in use of fertilizer B for good corn production in Kentucky. Plant available B is greatly affected by soil pH and decreases with increasing soil pH. Because of this, some states recommend use of B on corn grown on soils with a pH of 6.1 or higher. Also, some commercial soil testing laboratories serving Kentucky routinely test for B, and often recommend its use for corn. This has resulted in many corn growers in Kentucky asking if they need to use B on corn

Catalytic Materials by Design

Recent activities of our group in the design of catalytic materials are briefly surveyed. Special attention is given to sol-gel-derived mixed oxide aerogels and organic-inorganic hybrid gels, and to supported noble metals with controlled particle size. Examples discussed embrace: organically modified titania-silica aerogels for the epoxidation of bulky olefins, Ru-containing silica hybrid gels for the synthesis of formic-acid derivatives, and colloid-derived supported gold catalysts with controlled metal particle size

Spin-gap opening accompanied by a strong magnetoelastic response in the S=1 magnetic dimer system Ba3BiRu2O9

Neutron diffraction, magnetization, resistivity, and heat capacity measurements on the 6H-perovskite Ba3BiRu2O9 reveal simultaneous magnetic and structural dimerization driven by strong magnetoelastic coupling. An isostructural but strongly displacive first-order transition on cooling through T*=176 K is associated with a change in the nature of direct Ru-Ru bonds within Ru2O9 face-sharing octahedra. Above T*, Ba3BiRu2O9 is an S=1 magnetic dimer system with intradimer exchange interactions J0/kB=320 K and interdimer exchange interactions J'/kB=-160 K. Below T*, a spin-gapped state emerges with \Delta\approx220 K. Ab initio calculations confirm antiferromagnetic exchange within dimers, but the transition is not accompanied by long range-magnetic order.Comment: 5 pages, 5 figures, accepted by Physical Review

PROFESSOR JOSÉ: VIVÊNCIAS E REFLEXÕES SOBRE UMA FORMAÇÃO EM EDUCAÇÃO FÍSICA

The article that we presented hás the objective of stimulate the reflection about the formation process of physical education professors to work in the schools. From the professor words we're going to analyze the question of the existing distancing between the academic formation that the students receive and the difficulties faced in the daily practice by the professors in confronting with the labor market.O artigo que apresentamos tem o objetivo de estimular a reflexão sobre os processos de formação de professores de Educação Física para atuar nas escolas. A partir das falas de um professor, vamos analisando a questão do distanciamento existente entre a formação académica que recebem os alunos e as dificuldades enfrentadas na prática cotidiana pelos professores ao se enfrentarem com o mercado de trabalho. The article that we presented hás the objective of stimulate the reflection about the formation process of physical education professors to work in the schools. From the professor words we're going to analyze the question of the existing distancing between the academic formation that the students receive and the difficulties faced in the daily practice by the professors in confronting with the labor market