Influence of heat treatments on the impact toughness of a Ti-stabilized 12%Cr supermartensitic stainless steel

The supermartensitic stainless steels (SMSS) are a relatively new class of corrosion resistant alloys developed to obtain a better combination of weldability, strength, toughness and corrosion resistance than conventional martensitic stainless steels. The final properties of SMSS are strongly influenced by quenching and tempering heat treatments. In this work, different routes of heat treatments were tested in a Ti-stabilized 12%Cr supermartensitic stainless steel with the objective to improve mechanical properties, specially the low temperature (-46oC) toughness. Double and triple quenching were tested and compared to single quenching heat treatments. Two tempering temperatures (500oC and 650oC) were tested. The results obtained with instrumented Charpy impact tests showed that a triple quenching treatment was able to increase the density of fine TiC particles and improve the mechanical properties of specimens heat treated by quenching and tempering at 650oC

Influence of cold deformation on microstructure, crystallographic orientation and tensile properties of an experimental austenitic Fe–26Mn-0.4C steel

The correlation between microstructure, crystallographic orientation and grain boundaries characteristics of an austenitic high manganese steel was systematically investigated. The as-received and cold-rolled specimens with 50% and 70% reduction were analyzed using Scanning Electron Microscopy (SEM), Electron Back-Scattered Diffraction (EBSD) and X-ray diffraction techniques. A significant increase in the fraction of low-energy S3 twin boundaries, from 16.21% to 24.41%, was found in the 70% deformed sample. This was coupled with the formation of {011} austenitic structure, and occurrence of twinning-induced plasticity. The ductile-brittle fracture mode observed in the 70% cold rolled sample, which can be attributed to the formation of the high fraction of low-energy S3 twin boundaries, minimized both the localized stored strain energy and lattice misfit and promoted dislocation glide. A potential employment of the investigated steel in the petroleum industry is discussed.Peer ReviewedPostprint (published version

Genomic analysis of two phlebotomine sand fly vectors of Leishmania from the New and Old World.

Phlebotomine sand flies are of global significance as important vectors of human disease, transmitting bacterial, viral, and protozoan pathogens, including the kinetoplastid parasites of the genus Leishmania, the causative agents of devastating diseases collectively termed leishmaniasis. More than 40 pathogenic Leishmania species are transmitted to humans by approximately 35 sand fly species in 98 countries with hundreds of millions of people at risk around the world. No approved efficacious vaccine exists for leishmaniasis and available therapeutic drugs are either toxic and/or expensive, or the parasites are becoming resistant to the more recently developed drugs. Therefore, sand fly and/or reservoir control are currently the most effective strategies to break transmission. To better understand the biology of sand flies, including the mechanisms involved in their vectorial capacity, insecticide resistance, and population structures we sequenced the genomes of two geographically widespread and important sand fly vector species: Phlebotomus papatasi, a vector of Leishmania parasites that cause cutaneous leishmaniasis, (distributed in Europe, the Middle East and North Africa) and Lutzomyia longipalpis, a vector of Leishmania parasites that cause visceral leishmaniasis (distributed across Central and South America). We categorized and curated genes involved in processes important to their roles as disease vectors, including chemosensation, blood feeding, circadian rhythm, immunity, and detoxification, as well as mobile genetic elements. We also defined gene orthology and observed micro-synteny among the genomes. Finally, we present the genetic diversity and population structure of these species in their respective geographical areas. These genomes will be a foundation on which to base future efforts to prevent vector-borne transmission of Leishmania parasites

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results