Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Entire DC Network
Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González
Differential Effects Of Canopy Trimming And Litter Deposition On Litterfall And Nutrient Dynamics In A Wet Subtropical Forest, Steven J. Hall, Whendee L. Silver, Grizelle González
Steven J. Hall
Humid tropical forests have the highest rates of litterfall production globally, which fuels rapid nutrient recycling and high net ecosystem production. Severe storm events significantly alter patterns in litterfall mass and nutrient dynamics through a combination of canopy disturbance and litter deposition. In this study, we used a large-scale long-term manipulation experiment to explore the separate and combined effects of canopy trimming and litter deposition on litterfall rates and litter nutrient concentrations and content. The deposition of fine litter associated with the treatments was equivalent to more than two times the annual fine litterfall mass and nutrient content in control …
Zsm-5 Coatings On β-Sic Monoliths: Possible New Structured Catalyst For The Methanol-To-Olefins Process, B. Madani, S. Ivanova, B. Louis, Jean-Philippe Tessonnier, M. J. Ledoux, C. Pham-Huu
Zsm-5 Coatings On β-Sic Monoliths: Possible New Structured Catalyst For The Methanol-To-Olefins Process, B. Madani, S. Ivanova, B. Louis, Jean-Philippe Tessonnier, M. J. Ledoux, C. Pham-Huu
Jean-Philippe Tessonnier
Structured zeolite/silicon carbide composites were succesfully synthesized by ZSM-5 coatings deposited on macroscopic â-SiC foams with medium surface area. A homogeneous coverage of the support (30 wt % zeolite) by ZSM-5 crystals, having 1 ím average size, was reached after a double-coating procedure. The ZSM-5/â-SiC composite materials were characterized by BET, XRD, SEM, and H/D exchange methods. 27Al MAS NMR analysis revealed that all aluminum was present in a tetrahedral coordination, thus sitting in the zeolite framework. The existence of a nanoscopic layer of silica and silicon oxycarbide on the surface of the support ensures the strong anchoring of the …
Generalized Planar Fault Energies And Twinning In Cu–Al Alloys, S. Kibey, J. B. Liu, Duane D. Johnson, H. Sehitoglu
Generalized Planar Fault Energies And Twinning In Cu–Al Alloys, S. Kibey, J. B. Liu, Duane D. Johnson, H. Sehitoglu
Duane D. Johnson
We report ab initio density functional theory calculations of generalized planar fault energies of fcc Cu–xAl (x=0, 5.0, and 8.3at.%) alloys. We investigate the effects of substitutional solute Al on the unstable intrinsic γus and twin γutstacking faultenergies (SFEs). Our results reveal an increased tendency of Cu–Al to deform preferentially by twinning with increasing Al content, consistent with experiment. We attribute this mechanical behavior to appreciable lowering of the twinning barrier γut, along with the stable intrinsic and twin SFEs.
Theory Of Thin-Skin Eddy-Current Interaction With Surface Cracks, Nicola Harfield, John R. Bowler
Theory Of Thin-Skin Eddy-Current Interaction With Surface Cracks, Nicola Harfield, John R. Bowler
Nicola Bowler
Eddy-current non-destructive evaluation is commonly performed at relatively high frequencies at which the skin depths are significantly smaller than the dimensions of a typical crack. A thin-skin analysis of eddy currents is presented in which the electromagnetic fields on the crack faces are described in terms of a potential which obeys a two-dimensional Laplace equation. Solutions of this equation for defects in both magnetic and non-magnetic materials are determined by applying thin-skin boundary conditions at the crack perimeter. The impedance change of an eddy-current coil due to the defect is then calculated by numerical evaluation of one-dimensional integrals over the …