Topics on High-Energy Elastic Hadron Scattering

We review the main results we have obtained in the area of high-energy elastic hadron scattering and presented in this series of Workshops on Hadronic Interactions. After an introduction to some basic experimental and theoretical concepts, we survey the results reached by means of four approaches: analytic models, model-independent analyses, eikonal models and nonperturbative QCD. Some of the ongoing researches and future perspectives are also outlined.Comment: 24 pages, 17 figures, typos corrected, one reference added and six references updated. Version to appear in Brazilian Journal of Physic

Exposure of metallic copper surface on Cu-Al2O3-carbon catalysts

The bifunctional nature of Cu---Al2O3-on-carbon catalysts, used in the direct catalytic conversion of ethanol to ethyl acetate, prompted an examination of the dispersion of Cu on the composite catalyst. For this, the N2O-method of Osinga et al. for estimation of bare metallic copper surface on composite copper catalysts has been adapted for use on a gravimetric adsorption unit and then applied to several promoted and supported copper catalysts. For catalysts with Cu/Al atomic ratio 0.8 to 26, all reduced at 300 °C, the copper surface is only 1–8% of the total surface of 500–560 m2/g, but 50–430 m2/g Cu. The maximum Cu dispersion is obtained for the catalyst with Cu/Al = 6, which is also one of the best catalysts for the esterification reaction. The Cu surface rapidly increases from 1 to 10% of the total surface as the temperature of reduction of the catalyst is raised from 100 to 400 °C. On a low area (32 m2/g) asbestos carrier, a relatively higher Cu coverage of 55% can be obtained, but the activity of this catalyst is very poor. On use in the esterification reaction, the carbon-supported catalyst gets a more reddish brown copper color, however there is no increase in the exposed copper area.\ud \ud X-ray microscan studies of the catalyst prove that the copper sites on the surface (in an 1 μ-thick layer) are mostly in close association with the Al sites of the alumina promoter. Results from catalyst testing show that these Cu---Al sites or junctions are necessary to catalyze the condensation to ester of the acetaldehyde formed in the primary dehydrogenation of ethanol over copper. The microscan studies on the same spot on one and the same catalyst particle indicate that the distribution of Cu and Al in the 1 μ-thick layer on the catalyst surface does undergo some alterations when the catalyst is reduced at 300 °C and subsequently used in the esterification reaction at 275 °C. The exact nature of these alterations is still not clear

Lexical Similarities and Differences in the Mathematics, Science and English Language Textbooks

The teaching of Science and Math in English in Malaysia is an area of great concern to educators and students alike. This study looks, in particular, at the common word classes among keywords identified in the Science, Math and English language Form One textbooks used in Malaysia and the differences in language use identified in the Science and Math textbooks

Extended Derivative Dispersion Relations

It is shown that, for a wide class of functions with physical interest as forward scattering amplitudes, integral dispersion relations can be replaced by derivative forms without any high-energy approximation. The applicability of these extended derivative relations, in the investigation of forward proton-proton and antiproton-proton elastic scattering, is exemplified by means of a Pomeron-Reggeon model with totally nondegenerate trajectories.Comment: 7 pages, 1 figure, contribution to "Sense of Beauty in Physics", Miniconference in Honor of Adriano Di Giacomo on his 70th Birthday, Pisa, Italy, Jan. 26-27, 200

Derivative dispersion relations above the physical threshold

We discuss some formal and practical aspects related to the replacement of Integral Dispersion Relations (IDR) by derivative forms, without high-energy approximations. We first demonstrate that, for a class of functions with physical interest as forward scattering amplitudes, this replacement can be analytically performed, leading to novel Extended Derivative Dispersion Relations (EDDR), which, in principle, are valid for any energy above the physical threshold. We then verify the equivalence between the IDR and EDDR by means of a popular parametrization for total cross sections from proton-proton and antiproton-proton scattering and compare the results with those obtained through other representations for the derivative relations. Critical aspects on the limitations of the whole analysis, from both formal and practical points of view, are also discussed in some detail.Comment: Final version, published in Brazilian Journal of Physics, V. 37, 358 (2007