Grain refinement in a AlZnMgCuTi alloy by intensive melt shearing: A multi-step nucleation mechanism

This is a post-print version of the article. Copyright @ 2010 Elsevier B.V.Direct chill (DC) cast ingots of wrought Al alloys conventionally require the deliberate addition of a grain refiner to provide a uniform as-cast microstructure for the optimisation of both mechanical properties and processability. Grain refiner additions have been in widespread industrial use for more than half a century. Intensive melt shearing can provide grain refinement without the need for a specific grain refiner addition for both magnesium and aluminium based alloys. In this paper we present experimental evidence of the grain refinement in an experimental wrought aluminium alloy achieved by intensive melt shearing in the liquid state prior to solidification. The mechanisms for high shear induced grain refinement are correlated with the evolution of oxides in alloys. The oxides present in liquid aluminium alloys, normally as oxide films and clusters, can be effectively dispersed by intensive shearing and then provide effective sites for the heterogeneous nucleation of Al3Ti phase. As a result, Al3Ti particles with a narrow size distribution and hence improved efficiency as active nucleation sites of alpha-aluminium grains are responsible for the achieved significant grain refinement. This is termed a multi-step nucleation mechanism.Funding was obtained from the EPRSC

Binding and neutralization of vascular endothelial growth factor (VEGF) and related ligands by VEGF Trap, ranibizumab and bevacizumab

Pharmacological inhibition of VEGF-A has proven to be effective in inhibiting angiogenesis and vascular leak associated with cancers and various eye diseases. However, little information is currently available on the binding kinetics and relative biological activity of various VEGF inhibitors. Therefore, we have evaluated the binding kinetics of two anti-VEGF antibodies, ranibizumab and bevacizumab, and VEGF Trap (also known as aflibercept), a novel type of soluble decoy receptor, with substantially higher affinity than conventional soluble VEGF receptors. VEGF Trap bound to all isoforms of human VEGF-A tested with subpicomolar affinity. Ranibizumab and bevacizumab also bound human VEGF-A, but with markedly lower affinity. The association rate for VEGF Trap binding to VEGF-A was orders of magnitude faster than that measured for bevacizumab and ranibizumab. Similarly, in cell-based bioassays, VEGF Trap inhibited the activation of VEGFR1 and VEGFR2, as well as VEGF-A induced calcium mobilization and migration in human endothelial cells more potently than ranibizumab or bevacizumab. Only VEGF Trap bound human PlGF and VEGF-B, and inhibited VEGFR1 activation and HUVEC migration induced by PlGF. These data differentiate VEGF Trap from ranibizumab and bevacizumab in terms of its markedly higher affinity for VEGF-A, as well as its ability to bind VEGF-B and PlGF

Measurement of D+- and D0 production in deep inelastic scattering using a lifetime tag at HERA

The production of D-+/-- and D-0-mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb(-1). The measurements cover the kinematic range 5 < Q(2) < 1000 GeV2, 0.02 < y < 0.7, 1.5 < p(T)(D) < 15 GeV and |eta(D)| < 1.6. Combinatorial background to the D-meson signals is reduced by using the ZEUS microvertex detector to reconstruct displaced secondary vertices. Production cross sections are compared with the predictions of next-to-leading-order QCD, which is found to describe the data well. Measurements are extrapolated to the full kinematic phase space in order to obtain the open-charm contribution, F-2(c (c) over bar), to the proton structure function, F-2

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Not AvailableThe present study was undertaken with aim to understand the perceptions of indigenous communities about climate change pattern and its local impacts on climate variables, seasons, agriculture, biodiversity and adaptive strategies in geographical and technological-isolated Pangi valley situated in Chamba district, Himachal Pradesh. Randomly selected 120 respondents were interviewed and their perceptions were recorded on pre-designed questionnaire. The climate change impacts are experienced in the form of decreased snowfall (98.3%), temperature rise (97.5%), late onset of monsoon (90.8%), decreased rainfall (76.7%), reduced snow-melted water availability (86.7%) and increased drought incidences (85.8%) of over the years. Further, these climatic changes affecting agriculture through early shifts in crop season (80.8%), shorter growing season (91.7%), introduction of fruit and vegetable crops (90.8%), increased incidence of insect-pest (81.2%) and diseases (84.2%) and thereby decline in crop yield (70%). However, majority of the respondents undertaken adaptive strategies such as crop diversification, traditional mixed-cropping, mixed farming, crop rotation and agroforestry/ agro-horticulture systems to cope with climate change but they are either little or unaware of modern farming practices such as snow water/glacier runoff harvesting, agro advisory services, mulching and zero tillage as adaptation strategies.Not Availabl

Characterization of Polycyclic Aromatic Hydrocarbons (PAHs), Iron and BlackCarbon within Street Dust from a Steel Industrial City, Central China

Twenty-two street dust samples collected from a small steel city, central China, were analyzed for 16 USEPA priority PAHs to investigate the concentration, spatial distribution relationship with black carbon (BC) and Iron (Fe), and the source apportionment and to assess the health risk of these compounds. The mean contents of PAHs, BC and Fe were 4.43 &micro;g g&ndash;1, 12837.97 mg kg&ndash;1, 70205.70 mg kg&ndash;1, respectively. The highest spot was in the surrounding of the E&rsquo;zhou Steel Plant and the Steel Rolling Mill of E&rsquo;zhou. The correlation analysis indicated that there was no obvious relationship between Fe with each other, the PAHs significantly correlated to black carbon (BC), which might be caused by the continuous emission sources of iron and steel production. The results of sources identification suggested that PAHs contaminations in street dust were a mixed source of industrial production and traffic emission combustion. The incremental lifetime and cancer risks (ILCRs) of exposing to PAHs in the street dust of the E&rsquo;zhou city for the three age groups (namely childhood, adolescence, adulthood) fluctuated with in the range of 10&ndash;6 to 10&ndash;4, indicating a potential of carcinogenic risk for exposed populations.</p