44 research outputs found
Exploring the tensile response in small carbon fibre composite bundles
Small composite bundles, AS4 carbon fibre epoxy, with a restricted number of reinforcing fibres, ca. 20, showed a progressive failure when tested in tension. In-situ acoustic emission observations under tensile load reveal that numerous fibres fail before ultimate failure of the small composite bundle, suggesting that isolated and individual fibre failures occur without compromising the integrity of the neighboring fibres or the small composite bundle’s overall mechanical performance. The average strength of the carbon fibres in small composite bundles was 9.6% higher than in standard lab-scale composite specimens using the same fibre type
Fine scale measurement and mapping of uranium in soil solution in soil and plant-soil microcosms, with special reference to depleted uranium
Background and aims: Residues from use of depleted uranium (DU) munitions pose a lasting environmental impact through persistent contamination of soils. Consequently, an understanding of the factors determining the fate of DU in soil is necessary. An understudied factor is the interaction of root exudates with DU. This study describes the use of ‘Single-Cell-Sampling-and-Analysis' (SiCSA) for the first time in soil and investigates the effects of root exudates on DU dissolution. Methods: Soil solutions from soil and plant-soil microcosms containing DU fragments were sampled and analysed using SiCSA and capillary electrophoresis/ICP-MS for organic acids and uranium. Results: Nanolitre volumes of soil solution were sampled and analysed. Soils with DU fragments but no citrate addition showed low uranium concentrations in contrast to those with added citrate. Lupin root exudation gave concentrations up to 8mM citrate and 4.4mM malate in soil solution which solubilised DU fragments yielding transient solution concentrations of up to 30mM. Conclusions: Root exudates solubilise DU giving high localised soil solution concentrations. This should be considered when assessing the environmental risk of DU munitions. The SiCSA method was used successfully in soil for the first time and enables investigations with high spatial and temporal resolution in the rhizosphere. Figur
Upconversion of Cellulosic Waste Into a Potential “Drop in Fuel” via Novel Catalyst Generated Using Desulfovibrio desulfuricans and a Consortium of Acidophilic Sulfidogens
The authors acknowledge with thanks, use of GC-FID/GC-MS supplied by Dr. Daniel Lester within the Polymer Characterization Research Technology Platform, University of Warwick and the help of Drs. B. Kaulich, T. Araki,and M. Kazemian at beamline IO8, Diamond Light Source, United Kingdom, who funded the synchrotron study (Award No. SP16407: Scanning X-ray Microscopy Study of Biogenic Nanoparticles; Improved Bionanocatalysts by Design) on I08 Scanning X-ray Microscopy beamline (SXM).The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fmicb.2019.00970/full#supplementary-materialBiogas-energy is marginally profitable against the “parasitic” energy demands of processing biomass. Biogas involves microbial fermentation of feedstock hydrolyzate generated enzymatically or thermochemically. The latter also produces 5-hydroxymethyl furfural (5-HMF) which can be catalytically upgraded to 2, 5-dimethyl furan (DMF), a “drop in fuel.” An integrated process is proposed with side-stream upgrading into DMF to mitigate the “parasitic” energy demand. 5-HMF was upgraded using bacterially-supported Pd/Ru catalysts. Purpose-growth of bacteria adds additional process costs; Pd/Ru catalysts biofabricated using the sulfate-reducing bacterium (SRB) Desulfovibrio desulfuricans were compared to those generated from a waste consortium of acidophilic sulfidogens (CAS). Methyl tetrahydrofuran (MTHF) was used as the extraction-reaction solvent to compare the use of bio-metallic Pd/Ru catalysts to upgrade 5-HMF to DMF from starch and cellulose hydrolyzates. MTHF extracted up to 65% of the 5-HMF, delivering solutions, respectively, containing 8.8 and 2.2 g 5-HMF/L MTHF. Commercial 5% (wt/wt) Ru-carbon catalyst upgraded 5-HMF from pure solution but it was ineffective against the hydrolyzates. Both types of bacterial catalyst (5wt%Pd/3-5wt% Ru) achieved this, bio-Pd/Ru on the CAS delivering the highest conversion yields. The yield of 5-HMF from starch-cellulose thermal treatment to 2,5 DMF was 224 and 127 g DMF/kg extracted 5-HMF, respectively, for CAS and D. desulfuricans catalysts, which would provide additional energy of 2.1 and 1.2 kWh/kg extracted 5-HMF. The CAS comprised a mixed population with three patterns of metallic nanoparticle (NP) deposition. Types I and II showed cell surface-localization of the Pd/Ru while type III localized NPs throughout the cell surface and cytoplasm. No metallic patterning in the NPs was shown via elemental mapping using energy dispersive X-ray microanalysis but co-localization with sulfur was observed. Analysis of the cell surfaces of the bulk populations by X-ray photoelectron spectroscopy confirmed the higher S content of the CAS bacteria as compared to D. desulfuricans and also the presence of Pd-S as well as Ru-S compounds and hence a mixed deposit of PdS, Pd(0), and Ru in the form of various +3, +4, and +6 oxidation states. The results are discussed in the context of recently-reported controlled palladium sulfide ensembles for an improved hydrogenation catalyst.This project was funded by NERC grant NE/L014076/1 to LM (Program: “Resource Recovery from Wastes”). The Science City Photoemission Facility used in this research was funded through the Science Cities Advanced Materials Project 1: “Creating and Characterizing Next Generation of Advanced Materials” with support from AWM and ERDF funds. The microscopy work was conducted at “Centro de Instrumentación Cientifica” at the University of Granada, Spain. This work was partially supported by the Spanish Government Sistema Nacional de Grantia Juvenil grant PEJ-2014-P-00391 (Promocion de Empleo Joven e Implantacion de la Garantia Juvenil 2014, MINECO) with a scholarship to JGB
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Death of the high street: identification, prevention, reinvention
Location is of paramount importance within the retail sector, yet defining locational obsolescence remains overlooked, despite significant concerns over the viability of parts of the complex sector. This paper reviews the existing literature and, through this, explores retail locational obsolescence, including the multi-spatial nature of the driving forces that range from the global economy, local markets and submarkets, to individual property-specific factors; and, crucially, the need to disentangle locational obsolescence from other important concepts such as depreciation and functional obsolescence that are often mistakenly used. Through this, a conceptual model, definition and diagnostic criteria are presented to guide future studies, policy development and the allocation of resources. Importantly, three stages are presented to enable the operationalization of the model, essential to future academic and industry studies as well as the ongoing development of policy in this economically important, complex and contentious area