Dynamic general equilibrium analysis of improved weed management in Australia's winter cropping systems

A recent analysis indicated that the direct financial cost of weeds to Australia’s winter grain sectorwas approximately $A1.2bn in 1998–1999. Costs of thismagnitude represent a large recurring productivity loss in an agricultural sector that is sufficient to impact significantly on regional economies.Using amulti-regional dynamic computable general equilibrium model, we simulate the general equilibrium effects of a hypothetical successful campaign to reduce the economic costs of weeds. We assume that an additional$50m of R&D spread over five years is targeted at reducing the additional costs and reduced yields arising from weeds in various broadacre crops. Following this R&D effort, one-tenth of the losses arising from weeds is temporarily eliminated, with a diminishing benefit in succeeding years. At the national level, there is a welfare increase of $700m in discounted net present value terms. The regions with relatively high concentrations of winter crops experience small temporary macroeconomic gains.CGE modelling, dynamics, weed management, Crop Production/Industries,

Prediction of the thermal release of transactinide elements (112 ≤ Z ≤ 116) from metals

Metallic catcher foils have been investigated on their thermal release capabilities for future superheavy element studies. These catcher materials shall serve as connection between production and chemical investigation of superheavy elements (SHE) at vacuum conditions. The diffusion constants and activation energies of diffusion have been extrapolated for various catcher materials using an atomic volume based model. Release rates can now be estimated for predefined experimental conditions using the determined diffusion values. The potential release behavior of the volatile SHE Cn (E112), E113, Fl (E114), E115, and Lv (E116) from polycrystalline, metallic foils of Ni, Y, Zr, Nb, Mo, Hf, Ta, and W is predicted. Example calculations showed that Zr is the best suited material in terms of on-line release efficiency and long-term operation stability. If higher temperatures up to 2773K are applicable, tungsten is suggested to be the material of choice for such experiment

Effect of substrate thermal resistance on space-domain microchannel

In recent years, Fluorescent Melting Curve Analysis (FMCA) has become an almost ubiquitous feature of commercial quantitative PCR (qPCR) thermal cyclers. Here a micro-fluidic device is presented capable of performing FMCA within a microchannel. The device consists of modular thermally conductive blocks which can sandwich a microfluidic substrate. Opposing ends of the blocks are held at differing temperatures and a linear thermal gradient is generated along the microfluidic channel. Fluorescent measurements taken from a sample as it passes along the micro-fluidic channel permits fluorescent melting curves to be generated. In this study we measure DNA melting temperature from two plasmid fragments. The effects of flow velocity and ramp-rate are investigated, and measured melting curves are compared to those acquired from a commercially available PCR thermocycler

Gas chromatography of indium in macroscopic and carrier-free amounts using quartz and gold as stationary phases

The chemical investigation of E113 is likely to become soon feasible. The determination of chemical properties of carrier-free amounts of the lighter homologues of element 113, especially indium and thallium, allows designing experimental set-ups and selecting experimental conditions suitable for performing these studies. Here, we present investigations of the interaction of indium species with quartz and gold surfaces. Deposition temperatures as well as enthalpies of adsorption were determined for indium Tdep=739±20°C (−ΔHads(In)=227±10kJ mol−1) and for indium hydroxide Tdep=250±20°C (−ΔHads(InOH)= 124±10kJ mol−1) respectively, on quartz. In case of adsorption of indium on a gold surface only a lower limit of the deposition temperature was established Tdep>980°C (−ΔHads(In)≥315±10kJ mol−1). Investigations of macroscopic amounts of indium in thermosublimation experiments at similar experimental conditions were instrumental to establish a tentative speciation of the observed indium specie

Adsorption interaction of carrier-free thallium species with gold and quartz surfaces

The adsorption interactions of thallium and its compounds with gold and quartz surfaces were investigated. Carrier-free amounts of thallium were produced in nuclear fusion reactions of alpha particles with thick gold targets. The method chosen for the studies was gas thermochromatography and varying the redox potential of the carrier gases. It was observed that thallium is extremely sensitive to trace amounts of oxygen and water, and can even be oxidized by the hydroxyl groups located on the quartz surface. The experiments on aquartz surface with O2, He, H2 gas in addition with water revealed the formation and deposition of only one thallium species - TlOH. The adsorption enthalpy was determined to be Δ HSiO2ads(TlOH) = −134±5kJ mol−1. Aseries of experiments using gold as stationary surface and different carrier gases resulted in the detection of two thallium species - metallic Tl (H2 as carrier gas) and TlOH (O2, O2+H2O and H2+H2O as pure carrier gas or carrier gas mixture) with Δ HAuads(Tl) = −270±10kJ mol− and Δ HAuads(TlOH) = −146±3kJ mol−1. These data demonstrate a weak interaction of TlOH with both quartz and gold surfaces. The data represent important information for the design of future experiments with the heavier homologue of Tl in group 13 of the periodic table - element 113 (E113

The thermal release of scandium from titanium metal - a simple way to produce pure 44Sc for PET application

The radionuclide-generator based access to radiopharmaceutical isotopes represents a valuable alternative to directly produced isotopes at particle accelerators or nuclear reactors. The 44Ti based generator is of increasing interest for the delivery of PET-radiopharmaceutical isotopes used for imaging. The product of this generator 44Sc represents with its 3.97h half-life and 94.3% positron branching[1] a very promising candidate for labeling PET radiopharmaceuticals. The long half-life of 58.9±0.3y[2] of the 44Ti assures a constant and long lasting production of the daughter nuclide. Here we present a gas phase separation method of scandium from titanium via thermal release in vacuum. Titanium foils were irradiated with 40Ar to produce scandium in multi-nucleon transfer reactions. Another production reaction used was the irradiation of titanium by neutrons from the SINQ neutron source at the Paul Scherrer Institute (PSI). The titanium metal foils containing 44mSc and 46Sc were heated up for time periods of 15 and 60min to temperatures between 900°C and 1500°C in vacuum. Thus, release properties of scandium from titanium under these conditions were studied. The released scandium was collected on tantalum foils and could be rinsed of with concentrated nitric acid resulting in carrier free scandium nitrate solutions. From the experimental results optimum release conditions are suggeste

Sharp weighted estimates for classical operators

We give a new proof of the sharp one weight $L^p$ inequality for any operator $T$ that can be approximated by Haar shift operators such as the Hilbert transform, any Riesz transform, the Beurling-Ahlfors operator. Our proof avoids the Bellman function technique and two weight norm inequalities. We use instead a recent result due to A. Lerner to estimate the oscillation of dyadic operators. Our method is flexible enough to prove the corresponding sharp one-weight norm inequalities for some operators of harmonic analysis: the maximal singular integrals associated to $T$, Dyadic square functions and paraproducts, and the vector-valued maximal operator of C. Fefferman-Stein. Also we can derive a very sharp two-weight bump type condition for $T$.Comment: We improve different parts of the first version, in particular we show the sharpness of our theorem for the vector-valued maximal functio

On the modeling, design and validation of two dimensional quasi-static eddy current forces in a mechanical oscillator.

Damping vibrations is important in the design of some types of inertial sensing devices. One method for adding damping to a device is to use magnetic forces generated by a static magnetic field interacting with eddy currents. In this report, we develop a 2-dimensional finite element model for the analysis of quasistatic eddy currents in a thin sheet of conducting material. The model was used for design and sensitivity analyses of a novel mechanical oscillator that consists of a shuttle mass (thin sheet of conducting material) and a set of folded spring elements. The oscillator is damped through the interaction of a static magnetic field and eddy currents in the shuttle mass. Using a prototype device and Laser Dopler Velocimetry (LDV), measurements were compared to the model in a validation study using simulation based uncertainty analyses. Measurements were found to follow the trends predicted by the model

Predicted and in situ performance of a solar air collector incorporating a translucent granular aerogel cover

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ElsevierThere is an opportunity to improve the efficiency of flat plate solar air collectors by replacing their conventional glass covers with lightweight polycarbonate panels filled with high performance aerogel insulation. The in situ performance of a 5.4m2 solar air collector containing granular aerogel is simulated and tested. The collector is incorporated into the external insulation of a mechanically ventilated end terrace house, recently refurbished in London, UK. During the 7 day test period, peak outlet temperatures up to 45 °C are observed. Resultant supply and internal air temperatures peak at 25–30 and 21–22 °C respectively. Peak efficiencies of 22–36% are calculated based on the proposed design across a range of cover types. Measured outlet temperatures are validated to within 5% of their predicted values. Estimated outputs range from 118 to 166 kWh/m2/year for collectors with different thickness granular aerogel covers, compared to 110 kWh/m2/year for a single glazed collector, 140 k h/m2/year for a double glazed collector and 202 kWh/m2/year for a collector incorporating high performance monolithic aerogel. Payback periods of 9–16 years are calculated across all cover types. An efficiency up to 60% and a payback period as low as 4.5 years is possible with an optimised collector incorporating a 10 mm thick granular aerogel cover.This work is supported by the EPSRC, Brunel University, Buro Happold Ltd. and the Technology Strategy Board