Direct electrochemical production of pseudo-binary Ti–Fe alloys from mixtures of synthetic rutile and iron(III) oxide

Combining the FFC-Cambridge process with field-assisted sintering technology (FAST) allows for the realisation of an alternative, entirely solid-state, production route for a wide range of metals and alloys. For titanium, this could provide a route to produce alloys at a lower cost compared to the conventional Kroll-based route. Use of synthetic rutile instead of high purity TiO2 offers further potential cost savings, with previous studies reporting on the reduction of this feedstock via the FFC-Cambridge process. In this study, mixtures of synthetic rutile and iron oxide (Fe2O3) powders were co-reduced using the FFC-Cambridge process, directly producing titanium alloy powders. The powders were subsequently consolidated using FAST to generate homogeneous, pseudo-binary Ti–Fe alloys containing up to 9 wt.% Fe. The oxide mixture, reduced powders and bulk alloys were fully characterised to determine the microstructure and chemistry evolution during processing. Increasing Fe content led to greater β phase stabilisation but no TiFe intermetallic phase was observed in any of the consolidated alloys. Microhardness testing was performed for preliminary assessment of mechanical properties, with values between 330–400 Hv. Maximum hardness was measured in the alloy containing 5.15 wt.% Fe, thought due to the strengthening effect of fine α phase precipitation within the β grains. At higher Fe contents, there was sufficient β stabilisation to prevent α phase transformation on cooling, leading to a reduction in hardness despite a general increase from solid solution strengthening

A clinical trial of Carbutamide (BZ 55) in diabetics admitted to hospital

No Abstrac

The stability of immiscible viscous fingering in Hele-Shaw cells with spatially varying permeability

In this paper, we investigate the stability of immiscible viscous fingering in Hele-Shaw cells with spatially varying permeability, across a range of capillary numbers. We utilise a coupled boundary element - radial basis function (BE –RBF) numerical method that adapts and moves with the growing interface, providing an efficient, high accuracy scheme to track the interfacial displacement of immiscible fluids. By comparing the interfacial evolution and growth rate in varying permeability cells to that in uniform cells, we can assess the relative stability of the perturbations as a consequence of the variable permeability. Numerical experiments in Hele-Shaw cells with gradually varying permeability highlight 3 aperture effects that control the interfacial stability: (1) Gradients in the capillary pressure (2) Local changes in fluid mobility (3) Variation in the viscous pressure gradient. In low capillary number regimes, we find that aperture effect 1 and 2 dominate, which (relatively) stabilise interfacial perturbations in converging geometries and destabilise perturbations in diverging geometries. In high capillary number regimes, aperture effect 3 dominates meaning the relative stability transitions; the interface is destabilised in converging cells and stabilised in diverging cells. We find an upper bound critical capillary number Cagt at which the relative stability transitions in our gradually varying cell as 1000<Cagt<1250, which is independent of both α and ϵ0. This result is much lower than the value of Cagt=9139 predicted by linear stability theory, due to significant non-linear perturbation growth. This transition links the results found in previous works performed at low and high capillary numbers, providing new insight into the viscous fingering instability in variable permeability cells. To conclude, we present simulations in Hele-Shaw cells with large geometric heterogeneities and anisotropy, in order to demonstrate the significant fluid re-distribution that can occur due to localised variations in cell permeability. Using periodic permeability distributions, we show the significant re-distribution of fluid that can occur due to large capillary pressure gradients in the capillary limit, and the channelling of flow that can occur in the viscous limit along anisotropic features

Enhancing Biodiversity and Multifunctionality of an Organic Farmscape in California’s Central Valley

Organic farmers in the USA increasingly manage the margins of previously monocultured farmed landscapes to increase biodiversity, e.g. they restore and protect riparian corridors, plant hedgerows and construct vegetated tailwater ponds. This study attempts to link habitat enhancements, biodiversity and changes in ecosystem functions by: 1. inventorying the existing biodiversity and the associated belowground community structure and composition in the various habitats of an organic farm in California’s Central Valley; and 2. monitoring key ecosystem functions of these habitats. Two years of inventories show greater native plant diversity in non-cropped areas. While nematode diversity did not differ between habitats, functional groups were clearly associated with particular habitats as were soil microbial communities (phospholipid fatty acid analysis). Earthworm diversity did not differ between habitats, but biomass was higher in non-cropped areas. Habitats with woody vegetation stored 20% of the farmscape’s total carbon (C), despite their relatively small size (only 5% of the total farm). Two years of monitoring data of farmscape C and nitrogen (N) through emissions, run-off and leaching showed distinct tradeoffs in function associated with each habitat. Clearly habitat restoration in field margins will increase both landscape biodiversity and the multifunctionality of the farmscape as a whole

Strongly focused light beams interacting with single atoms in free space

We construct 3-D solutions of Maxwell's equations that describe Gaussian light beams focused by a strong lens. We investigate the interaction of such beams with single atoms in free space and the interplay between angular and quantum properties of the scattered radiation. We compare the exact results with those obtained with paraxial light beams and from a standard input-output formalism. We put our results in the context of quantum information processing with single atoms.Comment: 9 pages, 9 figure

The incidence and make up of ability grouped sets in the UK primary school

The adoption of setting in the primary school (pupils ability grouped across classes for particular subjects) emerged during the 1990s as a means to raise standards. Recent research based on 8875 children in the Millennium Cohort Study showed that 25.8% of children in Year 2 were set for literacy and mathematics and a further 11.2% of children were set for mathematics or literacy alone. Logistic regression analysis showed that the best predictors of being in the top set for literacy or mathematics were whether the child was born in the Autumn or Winter and cognitive ability scores. Boys were significantly more likely than girls to be in the bottom literacy set. Family circumstances held less importance for setting placement compared with the child’s own characteristics, although they were more important in relation to bottom set placement. Children in bottom sets were significantly more likely to be part of a long-term single parent household, have experienced poverty, and not to have a mother with qualifications at NVQ3 or higher levels. The findings are discussed in relation to earlier research and the implications for schools are set out

Connected Green function approach to ground state symmetry breaking in Φ1+14\Phi^4_{1+1}-theory

Using the cluster expansions for n-point Green functions we derive a closed set of dynamical equations of motion for connected equal-time Green functions by neglecting all connected functions higher than $4^{th}$ order for the $\lambda \Phi^4$-theory in $1+1$ dimensions. We apply the equations to the investigation of spontaneous ground state symmetry breaking, i.e. to the evaluation of the effective potential at temperature $T=0$. Within our momentum space discretization we obtain a second order phase transition (in agreement with the Simon-Griffith theorem) and a critical coupling of $\lambda_{crit}/4m^2=2.446$ as compared to a first order phase transition and $\lambda_{crit}/4m^2=2.568$ from the Gaussian effective potential approach.Comment: 25 Revtex pages, 5 figures available via fpt from the directory ugi-94-11 of [email protected] as one postscript file (there was a bug in our calculations, all numerical results and figures have changed significantly), ugi-94-1

An Off-lattice Model for Br Electrodeposition on Au(100): from DFT to Experiment

Since Br adsorption on Au(100) displays an incommensurate ordered phase, a lattice-gas treatment of the adlayer configurations is not reliable. We therefore use density functional theory slab calculations to determine the parameters necessary for the construction of an off-lattice model. We compute and analyze the total energy and electron density as the lateral Br position and coverage are varied. This allows the calculation of the corrugation potential, the short-range lateral interactions, the dipole moment (long-range interactions), and the residence charge. From these parameters, we construct an off-lattice model with no freely adjustable parameters. The simulation results compare remarkably well with experimental results.Comment: 42 pages, 15 embedded figures, submitted to Surface Scienc

Host-parasite biology in the real world: the field voles of Kielder

Peer reviewedPublisher PD

Coulomb Effects on Electromagnetic Pair Production in Ultrarelativistic Heavy-Ion Collisions

We discuss the implications of the eikonal amplitude on the pair production probability in ultrarelativistic heavy-ion transits. In this context the Weizs\"acker-Williams method is shown to be exact in the ultrarelativistic limit, irrespective of the produced particles' mass. A new equivalent single-photon distribution is derived which correctly accounts for the Coulomb distortions. As an immediate application, consequences for unitarity violation in photo-dissociation processes in peripheral heavy-ion encounters are discussed.Comment: 13 pages, 4 .eps figure