Preparation of MnO<Subscript><Emphasis Type=Italic>x</Emphasis></Subscript>/AISI 304 Austenitic Stainless Steel Monoliths for Catalytic Combustion of Ethyl Acetate

Abstract  

The objective of this study is to explore the treatment conditions of austenitic stainless steel, AISI 304, for catalytic devices used in volatile organic compounds (VOCs) combustion. The variables studied were treatment exposure time, temperature and atmosphere. AISI 304 steel surface resulted in different morphologies depending on temperature and atmosphere. The oxide layer was composed of mixed oxides of Cr–Fe and Cr–Mn–Fe, forming octahedral and hexagonal crystals. The addition of manganese with the objective of reaching the ideal Mn/Fe ratio improved notably the catalytic performance.     

Study on bisphenol-A polycarbonates samples crystallized by acetone vapor induction

Bisphenol-A polycarbonate (PC) is an important amorphous engineering polymer, which can have its crystallinity induced by special environmental conditions. Such crystallization can alter PC properties leading to flaws during its use or to new applications. Cast film samples of PC, prepared from chloroform solutions, were submitted to acetone vapor and characterized by polarized light microscopy (PLM), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). PLM showed that the PC crystalline structure was presented as spherulites of different sizes. DSC analysis exhibited a multiple melting behavior for the crystalline structure. FTIR has presented bands shifting and intensity decrease, compared to the samples before treatment. Compression molded samples were characterized by scanning electron microscopy (SEM), DSC and mechanical properties tests. For those samples, DSC also showed the presence of a crystalline phase, with a little increase on surface rugosity observed through SEM. Stress–strain tests presented a decrease on samples performance after acetone exposure.     

A gender analysis of top scientists’ collaboration behavior: evidence from Italy

Scientometrics - This work analyzes the differences in collaboration behavior between males and females among a particular type of scholars: top scientists, and as compared to non top scientists....     

The effect of multidisciplinary collaborations on research diversification

This work verifies whether research diversification by a scientist is in some measure related to their collaboration with multidisciplinary teams. The analysis considers the publications achieved by 5300 Italian academics in the sciences over the period 2004–2008. The findings show that a scientist’s outputs resulting from research diversification are more often than not the result of collaborations with multidisciplinary teams. The effect becomes more pronounced with larger and particularly with more diversified teams. This phenomenon is observed both at the overall level and for the disciplinary macro-areas.     

Embryonic diapause and its regulation

Embryonic diapause, a condition of temporary suspension of development of the mammalian embryo, occurs due to suppression of cell proliferation at the blastocyst stage. It is an evolutionary strategy to ensure the survival of neonates. Obligate diapause occurs in every gestation of some species, while facultative diapause ensues in others, associated with metabolic stress, usually lactation. The onset, maintenance and escape from diapause are regulated by cascades of environmental, hypophyseal, ovarian and uterine mechanisms that vary among species and between the obligate and facultative condition. In the best-known models, the rodents, the uterine environment maintains the embryo in diapause, while estrogens, in combination with growth factors, reinitiate development. Mitotic arrest in the mammalian embryo occurs at the G0 or G1 phase of the cell cycle, and may be due to expression of a specific cell cycle inhibitor. Regulation of proliferation in non- mammalian models of diapause provide clues to orthologous genes whose expression may regulate the reprise of proliferation in the mammalian context.     

Generalized Discrete Radon Transforms and Their Use in the Ridgelet Transform

We introduce and study a new class of Radon transforms in a discrete setting for the purpose of applying them to the ridgelet and curvelet transforms. We give a detailed analysis of the p-adic case and provide a closed-form formula for an inverse of the p-adic Radon transform. We give conditions for a scaled version of the generalized discrete Radon transform to yield a tight frame, and discuss a direct Radon matrix method for the implementation of a local ridgelet transform. We then study the effectiveness of some types of the generalized Radon transforms in reducing a type of noise known as speckle that is present in synthetic aperture radar (SAR) imagery. Flavia Colonna received the M.A. degree and the Ph.D degree in mathematics from the University of Maryland (College Park) in 1980 and 1985, respectively. She was an assistant professor at the University of Bari (Italy) until she joined the faculty of George Mason University in 1986, where she is currently professor of mathematics. Her research interests include discrete harmonic analysis, integral geometry, potential theory, and classical complex function theory. Glenn R. Easley received the B.S. degree (with honors) and the M.A. degree in mathematics from the University of Maryland, College Park, in 1993 and 1996, respectively, and the Ph.D. degree in computational science and informatics from George Mason University in 2000. Since 2000, he has been working for System Planning Corporation in signal and image processing. His research interests include computational harmonic analysis, wavelet analysis, synthetic aperture radar, deconvolution and computer vision.This revised version was published online in June 2005 with correction to CoverDate     

Lateral displacement of a beam incident from a uniaxial medium onto a metal

Abstract

The reflection of spatially limited beams at the flat boundary between a uniaxial crystal and a metal is studied theoretically. Incident limited beams are expanded in terms of the ordinary and extraordinary plane waves that can be propagated in uniaxial media. The spatial modifications in ordinary and extraordinary reflected field distributions are numerically calculated. Several effects, including polarization conversion between ordinary and extraordinary waves and field enhancement on the interface due to the excitation of surface waves, are discussed. The numerical calculations of the Goos–Hänchen lateral shift in the reflected fields are compared with the results predicted by the extension to uniaxial media of the stationary phase approximation used for limited beams in isotropic media.