271 research outputs found

    Improving tribological properties of cast Al-Si alloys through application of wear-resistant thermal spray coatings

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    Flame Spray Thermal Spray coatings are low-cost, high-wear surface-treatment technologies. However, little has been reported on their potential effects on cast automotive aluminum alloys. The aim of this research was to investigate the tribological properties of as-sprayed NiCrBSi and WC/12Co Flame Spray coatings applied to two cast aluminum alloys: high-copper LM24 (AlSi8Cu3Fe), and low-copper LM25 (AlSi7Mg). Potential interactions between the mechanical properties of the substrate and the deposited coatings were deemed to be significant. Microstructural, microhardness, friction, and wear (pin-on-disk, microabrasion, Taber abrasion, etc.) results are reported, and the performance differences between coatings on the different substrates were noted. The coefficient of friction was reduced from 0.69-0.72 to 0.12-0.35. Wear (pin-on-disk) was reduced by a factor of 103-104, which was related to the high surface roughness of the coatings. Microabrasion wear was dependent on coating hardness and applied load. Taber abrasion results showed a strong dependency on the substrate, coating morphology, and homogeneity

    EU economic integration agreements, Brexit and trade

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    The effects of regionalism on trade have been extensively evaluated within a gravity model framework. With the expected exit of the United Kingdom (UK) from the European Union (EU), the prospect of regional disintegration has brought about a new impetus to studying trade policy effects. Using actual and forecast data for a panel of bilateral imports between the EU15 and the rest of the world, this paper examines the trade effects of EU economic integration agreements (EIAs), their evolution over time and the related counterfactual Brexit trade policy scenarios. Distinct trade effects are obtained for the EU trade related agreements; positive, significant and of similar magnitude for the EU and free trade agreement (FTA) coefficients, but negative and significant (and smaller in magnitude) for the regional economic partnership agreements (EPAs). The subperiod results suggest the positive coefficients of EU and FTA membership tend to diminish over time, implying earlier membership of EIAs came with greater trade benefits. Finally, in generating the predicted values for the trade effects of three alternative counterfactual Brexit scenarios (hard Brexit, hard Brexit plus, global Britain), the findings suggest an asymmetric effect depending on the perspective of the UK versus the EU. Whereas the UK’s trade would decline substantially with all three country groups (the EU, the FTAs and regional EPAs) and rise substantially with the rest of the world, only minor percentage changes are predicted for EU bilateral trade

    The need for international perspectives to solve global biosecurity challenges

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    Global biosecurity presents international challenges because the majority of instances of novel organism introductions are due to international movements of goods, food and people and the likelihood of introduced agents crossing political boundaries. The inherent vulnerability of environments to introductions of alien, or non-indigenous, biological agents is due to the greater ecological vulnerability to these exotic entrants in the receiving environment. Agencies and individuals responsible for approving intentional introductions of beneficial organisms recognize this relationship and consider potential impacts in risk assessments prior to release of the organisms. However, some of those responsible for detection and control of novel pathogens and pests, introduced either inadvertently or intentionally, lack extensive training in ecology, environmental biology, and pathology, and may therefore underestimate the risk from such events. The latter is a key factor in the case of food safety. Europe is particularly vulnerable to cross-border movement of introduced agents, and one response to this has been the recent revision of plant health regimes throughout the European Union. Other responses include project-based initiatives, such as PLANTFOODSEC

    A stochastic frontier analysis of trade efficiency for the new EU member states: implications of Brexit

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    Examining the trade performance for the new European Union (EU) member states is an important issue in the context of the enlargement process – and in a new era of membership contraction with the likely exit of the United Kingdom from the EU. Typically, the degree of trade integration is assessed by comparing actual trade volumes with potential trade volumes projected from the gravity model parameters estimated for a reference group of countries that best represent normal trade relations. This approach, however, does not compare trade levels against a maximum level of trade defined by a stochastic frontier. In this paper, a stochastic frontier specification of the gravity model is used to identify the efficiency of trade integration relative to maximum trade levels. The findings, based on a panel dataset of bilateral exports from 18 Western European countries to the 13 new member states over the 1995-2022 period, indicate a high degree of trade integration close to two-thirds of frontier estimates. Using forecast data for 2017-2022, trade efficiency should remain broadly stable and even increase for the larger countries in the likely post-Brexit phase

    Foreign direct investment performance: a stochastic frontier analysis of location and variance determinants

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    The opening up process of the eastern European countries was marked by greater integration of foreign direct investment (FDI) with their western neighbouring countries. Using the single step maximum likelihood (ML) approach to stochastic frontier analysis (SFA), the location and variance determinants of FDI are estimated using the knowledge capital (KK) model framework. The findings, based on a panel of bilateral FDI stocks from 10 western to 10 eastern European countries over the 1996 to 2007 period, suggest FDI is determined by both horizontal and vertical motives while the process of liberalisation and infrastructural developments significantly reduce the variance of FDI. In using a stochastic frontier specification of the KK model, the efficiency of FDI performance is identified relative to maximum levels. The bilateral efficiency scores suggest a mixed performance, indicating scope to improve the efficiency of FDI

    Foreign direct investment in the eastern European countries: determinants and performance

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    This paper assesses the determinants, changing nature and the performance of foreign direct investment (FDI) in the eastern European countries within the knowledge capital (KK) model framework. The findings from a panel of bilateral FDI stocks from 10 western European countries to 10 eastern European countries over the years 1996–2007 indicate the presence of both vertical and horizontal motives of FDI with a shift over time towards the latter. In identifying the efficiency of FDI integration relative to maximum potential levels, the stochastic frontier specification of the KK model indicates a mixed degree of FDI performance

    Substrate finishing and niobium content effects on the high temperature corrosion resistance in steam atmosphere of CrN/NbN superlattice coatings deposited by PVD-HIPIMS

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    The main objective of this work was to evaluate the oxidation resistance of three PVD-HIPIMS CrN/NbN coatings, studying the effect of the surface finishing of the substrate and the role of niobium content into the coating composition. CrN/NbN nano-multilayered films on P92 steel were tested at 650°C in pure steam atmosphere. The mass gain was measured at fixed intervals to study their oxidation kinetics. The morphology and thickness of nanoscales were measured by transmission electron microscopy (TEM). Characterization of coatings before and after the thermal treatment was performed by scanning electron microscopy-energy with facilities of dispersive X-ray spectroscopy (SEM–EDX) and X-ray diffraction (XRD). All coatings improved the oxidation resistance of the substrate material, but the best behaviour was exhibited by the CrN/NbN with the high niobium (Nb) content and deposited on the substrate with the finest surface finishing

    Prion protein-specific antibodies that detect multiple TSE agents with high sensitivity

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    This paper describes the generation, characterisation and potential applications of a panel of novel anti-prion protein monoclonal antibodies (mAbs). The mAbs were generated by immunising PRNP null mice, using a variety of regimes, with a truncated form of recombinant ovine prion protein spanning residues 94–233. Epitopes of specific antibodies were mapped using solid-phase Pepscan analysis and clustered to four distinct regions within the PrP molecule. We have demonstrated the utility of these antibodies by use of Western blotting and immunohistochemistry in tissues from a range of different species affected by transmissible spongiform encephalopathy (TSE). In comparative tests against extensively-used and widely-published, commercially available antibodies, similar or improved results can be obtained using these new mAbs, specifically in terms of sensitivity of detection. Since many of these antibodies recognise native PrPC, they could also be applied to a broad range of immunoassays such as flow cytometry, DELFIA analysis or immunoprecipitation. We are using these reagents to increase our understanding of TSE pathogenesis and for use in potential diagnostic screening assays

    The ongoing pursuit of neuroprotective therapies in Parkinson disease

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    Many agents developed for neuroprotective treatment of Parkinson disease (PD) have shown great promise in the laboratory, but none have translated to positive results in patients with PD. Potential neuroprotective drugs, such as ubiquinone, creatine and PYM50028, have failed to show any clinical benefits in recent high-profile clinical trials. This 'failure to translate' is likely to be related primarily to our incomplete understanding of the pathogenic mechanisms underlying PD, and excessive reliance on data from toxin-based animal models to judge which agents should be selected for clinical trials. Restricted resources inevitably mean that difficult compromises must be made in terms of trial design, and reliable estimation of efficacy is further hampered by the absence of validated biomarkers of disease progression. Drug development in PD dementia has been mostly unsuccessful; however, emerging biochemical, genetic and pathological evidence suggests a link between tau and amyloid-β deposition and cognitive decline in PD, potentially opening up new possibilities for therapeutic intervention. This Review discusses the most important 'druggable' disease mechanisms in PD, as well as the most-promising drugs that are being evaluated for their potential efficiency in treatment of motor and cognitive impairments in PD
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