A numerical investigation of wind speed effects on lake-effect storms

Observations of lake-effect storms that occur over the Great Lakes region during late autumn and winter indicate a high sensitivity to ambient wind speed and direction. In this paper, a two-dimensional version of the Penn State University/National Center for Atmospheric Research (PSU/NCAR) model is used to investigate the wind speed effects on lake-effect snowstorms that occur over the Great Lakes region.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42510/1/10546_2004_Article_BF00708966.pd

Combining advanced characterization techniques to rationalize the multiple mechanical behaviors observed in TRIP/TWIP Ti-alloys

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Combining advanced characterization techniques to rationalize the multiple mechanical behaviors observed in TRIP/TWIP Ti-alloys

Web conferenceInternational audienc

Characterization of a new human monoclonal antibody directed against the Vel antigen

International audienceBACKGROUND AND OBJECTIVES: The Vel blood group antigen is a poorly characterized high-prevalence antigen. Until now, anti-Vel antibodies have been observed in only alloimmunized Vel-negative individuals. In this study, we aimed to establish a human hybridoma cell line secreting the first anti-Vel monoclonal antibody (mAb), clone SpG213Dc. MATERIALS AND METHODS: Peripheral blood lymphocytes from a French Vel-negative woman with anti-Vel in her plasma were transformed with Epstein-Barr virus and then hybridized with the myeloma cell line Sp2/O-Ag14 using the polyethylene glycol (PEG) method. A specific anti-Vel mAb was successfully produced and was extensively characterized by serological, flow cytometry and Western blot analyses. RESULTS: One human anti-Vel-secreting clone was produced and the secreted anti-Vel mAb (SpG213Dc) was examined. The specificity of the SpG213Dc mAb was assessed by its reactivity against a panel of nine genotyped RBCs including, respectively, three Vel-negative and six Vel-positive (three wild-type homozygous and three heterozygous) samples using flow cytometry method. Vel-positive RBCs were specifically stained and were subsequently used to perform Western blot and immunoprecipitation analysis of the Vel antigen. CONCLUSION: Serological characterization of the new monoclonal anti-Vel SpG213Dc showed a heterogeneous level of expression of the Vel antigen on the different RBCs. Our results suggest that the mAb SpG213Dc can be reliably used as a blood grouping reagent, thus allowing the mass-scale phenotyping of blood donors to strengthen rare blood banks with Vel-negative RBC unit

The Influence of Twinning on the Strain–Hardenability in TRIP/TWIP Titanium Alloys Role of Solute–Solution Strengthening

International audienceTransformation Induced Plasticity and Twinning Induced Plasticity (TWIP) titanium alloys are well-known to display a good combination of strain–hardenability and ductility. However, a large range of strain–hardening rates, which cannot be predicted by the actual design method based on electronic parameters, is obtained. In order to explain this wide range of properties, two different alloys displaying a large difference of strain–hardening rates, but similar chemical stability, have been studied and compared Ti–12Mo and Ti–8.5Cr–1.5Sn (in wt%). Evolution of both twin size and density during in situ tensile tests has been followed by SEM/electron backscatter diffraction mapping, and two distinct behaviors can be highlighted the growth of existing twins (Ti–12Mo) and the nucleation of new twins (Ti–8.5Cr–1.5Sn) upon loading. The last one may lead to an improvement of the dynamic Hall–Petch effect by multiplication of twin/matrix interfaces, with subsequent improvement of the macroscopic strain–hardening. It is thought that this competition may be related to the crystal lattice distortion induced by the alloying elements and the subsequent reduction of the migration velocity of the twin/matrix interfaces. Impact Statement This work reports on distinct behaviors of mechanical twins in TRIP/TWIP titanium alloys, highlighting for the first time a competition between growth of existing twins and nucleation of additional twins upon loading. This effect is assumed to be due to the solute-strengthening effect in the studied alloys and modify, as a consequence, the strain–hardenability of the TRIP/TWIP alloys

Combining tensile tests and nanoindentation to explore the strengthening of high and medium entropy alloys

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Strain-hardenability of new strengthened TRIP/TWIP titanium alloys

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From single phase to dual-phase TRIP-TWIP alloys: design approach and properties

International audienceAiming at increasing the yield strength of transformation and twinning induced plasticity (TRIP and TWIP) titanium alloys while maintaining a good work-hardening, a dual-phase α/β alloy is designed and studied. The composition Ti-7 Cr-1.5 Sn (wt.%) is proposed, based on an approach coupling Calphad calculations and classical Bo-Md design tool used in Ti-alloys. Its microstructure is made of 20% of α precipitates in a β matrix, the matrix having optimal Bo and Md parameters for deformation twinning and martensitic transformation. The alloy indeed displays a yield strength of 760 MPa, about 200 MPa above that of a Ti-8.5Cr-1.5Sn (wt.%) single β phase TRIP/TWIP alloy, combined with good work-hardening and ductility. In situ synchrotron X ray diffraction and post-mortem electron back-scattered analyses are performed to characterize the deformation mechanisms. They 2 evidence that the TRIP and TWIP mechanisms are successfully obtained in the material, validating the design strategy. The interaction of the precipitates with the {332} β twins is analyzed, evidencing that the precipitates are sheared when hit by a twin, and therefore do not hinder the propagation of the twins. The nature of the interaction is discussed, as well as the impact of the precipitates on the mechanical properties

On the heterogeneous nature of deformation in a strain-transformable beta metastable Ti-V-Cr-Al alloy

International audienceTi-10V-4Cr-1Al wt% (TVCA) is a new grade of titanium alloy, developed to combine twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) effects. The TVCA alloy exhibits a very high strain-hardening rate and an excellent balance between strength and ductility for great potential in aerospace applications. Deformation mechanisms are investigated using in-situ techniques as synchrotron X-ray diffraction (SXRD) and in-situ electron backscatter diffraction (EBSD) analysis during tensile strain, as well as transmission electron microscopy (TEM). The results reveal that permanent {332} mechanical twinning and an unstable orthorhombic α” martensite are the major deformation products. This study aims at unveiling the interaction and co-deformation of the various deformation features, that lead to the outstanding mechanical properties of the alloy. The very high strain hardening rate could be explained by the simultaneous activation of two different deformation modes, the primary TRIP mode on one side, and the hybrid TWIP and secondary TRIP mode on the other one, in different grains, resulting in in-grain dynamic hardening (Hall-Petch)/softening (α” martensite) effects and meso-scale dynamic mechanical contrast. Selection of the deformation mechanism – TRIP or TWIP –, which seems to be inhomogeneous, at both the inter- and the intra-granular level, is investigated