Effects of substituting ytterbium for scandium on the microstructure and age-hardening behaviour of Al-Sc alloy

In order to reduce the cost of Al-Sc alloys and maintain their mechanical properties, the microstructure and mechanical properties of Al-0.24 wt% Sc-0.07 wt% Yb in comparison with Al-0.28 wt% Sc alloys were studied. The aging behaviour, precipitate morphologies, precipitate coarsening and precipitation hardening of both alloys were investigated. The average diameter and the size distribution of nanoscale Al3Sc and Al-3(Sc,Yb) precipitates at various aging conditions were measured. Transmission electron microscopy (TEM) and high-resolution TEM were used to deeply understand the precipitate evolution. A maximum hardness around 73 (HV30) was obtained with a precipitate diameter from 4.3 to 5.6 nm for both alloys. (c) 2014 Elsevier B.V. All rights reserved.

Population differentiation and speciation in the genus Characidium (Characiformes: Crenuchidae): effects of reproductive and chromosomal barriers

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Confinement effects and why carbon nanotube bundles can work as gas sensors

Carbon nanotubes have been at the forefront of nanotechnology, leading not only to a better understanding of the basic properties of charge transport in one dimensional materials, but also to the perspective of a variety of possible applications, including highly sensitive sensors. Practical issues, however, have led to the use of bundles of nanotubes in devices, instead of isolated single nanotubes. From a theoretical perspective, the understanding of charge transport in such bundles, and how it is affected by the adsorption of molecules, has been very limited, one of the reasons being the sheer size of the calculations. A frequent option has been the extrapolation of knowledge gained from single tubes to the properties of bundles. In the present work we show that such procedure is not correct, and that there are qualitative differences in the effects caused by molecules on the charge transport in bundles versus isolated nanotubes. Using a combination of density functional theory and recursive Green's function techniques we show that the adsorption of molecules randomly distributed onto the walls of carbon nanotube bundles leads to changes in the charge density and consequently to significant alterations in the conductance even in pristine tubes. We show that this effect is driven by confinement which is not present in isolated nanotubes. Furthermore, a low concentration of dopants randomly adsorbed along a two-hundred nm long bundle drives a change in the transport regime; from ballistic to diffusive, which can account for the high sensitivity to different molecules.

Low Dose of the Anesthetic Propofol Does Not Induce Genotoxic or Mutagenic Effects in Nile Tilapia

We demonstrate the efficacy of propofol (2,6-diisopropylphenol) as an anesthetic when administered to fish in an immersion bath and show the absence of genetic side effects following short-term exposure to the drug. All tested fish were anesthetized (as indicated by loss of posture and lack of response to physical stimulation), and both the comet assay (tail intensity) and the micronucleus assay revealed that propofol does not induce primary DNA damage or chromosome damage in the fish Nile Tilapia Oreochromis niloticus. Our results should be considered in light of our particular test conditions, including the water temperature (similar to 25 degrees C), the life stage and size of the fish, and the single exposure to the anesthetic. We suggest that propofol is a promising anesthetic in terms of its lack of genotoxic effects, at least in low dosages in adult Nile Tilapia.Received June 25, 2013; accepted October 15, 2013

Multi-vortex State Induced by Proximity Effects in a Small Superconducting Square

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structural properties of beds packed with agro-industrial solid by-products applicable for solid-state fermentation: Experimental data and effects on process performance

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of LLLT on autogenous bone grafts in the repair of critical size defects in the calvaria of immunosuppressed rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Differential environmental impacts on small and medium size rivers from center of São Paulo State, Brazil, and regional management perspectives

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Patch size, functional isolation, visibility and matrix permeability influences neotropical primate occurrence within highly fragmented landscapes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Characterization of Soil Surface Roughness Effects on Runoff and Soil Erosion Rates under Simulated Rainfall

This study aims at identifying the influence of soil surface roughness from small to large aggregates (random roughness) on runoff and soil loss and to investigate the interaction with soil surface seal formation. Bulk samples of a silty clay loam soil were sieved to four aggregate-size classes of 3 to 12, 12 to 20, 20 to 45, 45 to 100 mm, and packed in soil trays set at a 5% slope. Rainfall simulations using an oscillating nozzle simulator were conducted for 90 min at an average rainfall intensity of 50.2 mm h(-1). Soil surface roughness was measured using an instantaneous profile laser scanner and surface sealing was studied by macroscopic analysis of epoxy impregnated soil samples. The rainfall simulations revealed longer times to initiate runoff with increasing soil surface roughness. For random roughness levels up to 6 mm, a decrease in final runoff rate with increasing roughness was observed. This can be attributed to a decreased breakdown of the larger roughness elements on rougher surfaces, thus keeping infiltration rate high. For a random roughness larger than 6 mm, a greater final runoff rate was observed. This was caused by the creation of a thick depositional seal in the concentrated flow areas, thus lowering the infiltration rates. Analysis of impregnated soil sample blocks confirmed the formation of a structural surface seal on smooth surfaces, whereas thick depositional seals were visible in the depressional areas of rougher surfaces. Therefore, from our observations it can be learned that soil surface roughness as formed by the presence of different aggregate sizes reduces runoff but that its effect diminishes due to aggregate breakdown and the formation of thick depositional seals in the case of rough soil surfaces. Sediment concentration increased with increasing soil surface roughness, due to runoff concentration in flow paths. Nevertheless, final soil loss rates were comparable for all soil roughness categories, indicating that random roughness is only important in influencing runoff rates and the time to initiate runoff, but not in influencing sediment export through soil loss rates.

Dominant predators mediate the impact of habitat size on trophic structure in bromeliad invertebrate communities

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Natural enemies depend on remnant habitat size in agricultural landscapes

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of acetylation and acetylation-hydroxypropylation (dual-modification) on the properties of starch from Carioca bean (Phaseolus vulgaris L.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Genetic gain in the selection by multi-effects index in open-pollinated progenies of Eucalyptus grandis Hill ex Maiden

In Brazil, Eucalyptus grandis Hill ex Maiden is widely used for commercial reforestation, especially for production of pulp, paper and energy. Its genetic variability is being explored in tree improvement programs for over 30 years. The objective of this work was to estimate genetic parameters and compare genetic gains by multi-effects index in a breeding population of E. grandis. Progeny tests were established using open-pollinated seeds from ten provenances ranging from 153 to 160 progenies established in a completely randomized block design in four sites of Sao Paulo State (Anhembi, Avere Itarare e Pratania). At 24 months of age the traits diameter at breast height (DBH), height (ALT) and volume (VOL) were measured. The individual site analyses indicated significant genetic differences among progenies, height genetic variability and the mean progeny heritability (> 0.70). For joint analyses of sites, significant differences in genotype x environmental interaction effects were detected, showing differences of performance of the progenies in different sites. The Itarare site gave high genetic gains, effective size and genetic diversity. The genetic diversity and low effective size are unviable factors; considering that the progeny tests studied should retain adequate levels of genetic variability in order to be transformed in future seedling seed orchards.

Body size and allometric shape variation in the molly Poecilia vivipara along a gradient of salinity and predation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)