305 research outputs found

    Synthesis Methods, Microscopy Characterization and Device Integration of Nanoscale Metal Oxide Semiconductors for Gas Sensing

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    A comparison is made between SnO2, ZnO, and TiO2 single-crystal nanowires and SnO2 polycrystalline nanofibers for gas sensing. Both nanostructures possess a one-dimensional morphology. Different synthesis methods are used to produce these materials: thermal evaporation-condensation (TEC), controlled oxidation, and electrospinning. Advantages and limitations of each technique are listed. Practical issues associated with harvesting, purification, and integration of these materials into sensing devices are detailed. For comparison to the nascent form, these sensing materials are surface coated with Pd and Pt nanoparticles. Gas sensing tests, with respect to H2, are conducted at ambient and elevated temperatures. Comparative normalized responses and time constants for the catalyst and noncatalyst systems provide a basis for identification of the superior metal-oxide nanostructure and catalyst combination. With temperature-dependent data, Arrhenius analyses are made to determine activation energies for the catalyst-assisted systems

    D.3.6 – Sediment dynamics and stability

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    The objective of the FAST project is to develop a Copernicus downstream service based on (Sentinel) satellite data and in situ data to assess the function of wetlands in reducing flood risk and erosion. This requires an assessment of the erodibility and stability of foreshores, as well as knowledge on how saltmarshes function and develop, in order to predict their future status, and hence their flood defence value over longer time-scales. While detailed results on sediment and marsh dynamics are presented in particularly Deliverable 5.2, this Deliverable 3.6 serves to lists publication output of the project related to the study of vertical and lateral sediment dynamics of foreshores and marsh range changes and their drivers. The potential for implementation of products and services related to sediment dynamics and stability in the Copernicus downstream service is discussed

    Processing of Nanostructured Devices Using Microfabrication Techniques

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    Systems and methods that incorporate nanostructures into microdevices are discussed herein. These systems and methods can allow for standard microfabrication techniques to be extended to the field of nanotechnology. Sensors incorporating nanostructures can be fabricated as described herein, and can be used to reliably detect a range of gases with high response

    Ankle motion is associated with soft tissue displacement in the dorsal thigh: an in vivo investigation suggesting myofascial force transmission across the knee joint

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    Experiments in cadavers have demonstrated significant mechanical interactions between constituents of myofascial chains. However, evidence for such force transmission effects is scarce under in vivo conditions. The purpose of this trial was to examine the impact of ankle motion on soft tissue displacement of the dorsal thigh. Eleven healthy active individuals (26.8 ± 4.3 years, six males), in prone position and with the knee extended, underwent passive calf stretches (ankle dorsal extension) imposed by an isokinetic dynamometer. High-resolution ultrasound was used to simultaneously capture the displacement of the semimembranosus muscle, which was quantified by means of cross-correlation analysis. Inactivity of the leg muscles was controlled using surface electromyography (EMG). One participant had to be excluded due to major EMG activity during the experiment. According to a one-sample t test testing the difference to the neutral zero position, ankle dorsal extension induced substantial caudal muscle displacements (5.76 ± 2.67 mm, p < 0.0001). Correlation analysis (Spearman), furthermore, revealed a strong association between maximal dorsal extension and semimembranosus motion (rho = 0.76, p = 0.02). In conclusion, the present trial provides initial in vivo evidence for a mechanical force transmission between serially connected skeletal muscles. This means that local alterations of the mechanical tissue properties may modify flexibility in neighboring (superior or inferior) joints

    Ice-margin and meltwater dynamics during the mid-Holocene in the Kangerlussuaq area of west Greenland

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    Land-terminating parts of the west Greenland ice sheet have exhibited highly dynamic meltwater regimes over the last few decades including episodes of extremely intense runoff driven by ice surface ablation, ponding of meltwater in an increasing number and size of lakes, and sudden outburst floods, or 'jökulhlaups', from these lakes. However, whether this meltwater runoff regime is unusual in a Holocene context has not been questioned. This study assembled high-resolution topographical data, geological and landcover data, and produced a glacial geomorphological map covering ~1200 km2. Digital analysis of the landforms reveals a mid-Holocene land-terminating ice margin that was predominantly cold-based. This ice margin underwent sustained active retreat but with multiple minor advances. Over c. 1000 years meltwater runoff became impounded within numerous and extensive proglacial lakes and there were temporary connections between some of these lakes via spillways. The ice-dams of some of these lakes had several quasi-stable thicknesses. Meltwater was apparently predominantly from supraglacial sources although some distributary palaeochannel networks and some larger bedrock palaeochannels most likely relate to mid-Holocene subglacial hydrology. In comparison to the geomorphological record at other Northern Hemisphere ice-sheet margins the depositional landforms in this study area are few in number and variety and small in scale, most likely due to a restricted sediment supply. They include perched fans and deltas and perched braidplain terraces. Overall, meltwater sourcing, routing and the proglacial runoff regime during the mid-Holocene in this land-terminating part of the ice sheet was spatiotemporally variable, but in a manner very similar to that of the present day

    Patterns and processes in shorebird survival rates: a global review

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    Changes in demographic rates underpin changes in population size, and understanding demographic rates can greatly aid the design and development of strategies to maintain populations in the face of environmental changes. However, acquiring estimates of demographic parameters at relevant spatial scales is difficult. Measures of annual survival rates can be particularly challenging to obtain because large-scale, long-term tracking of individuals is difficult and the resulting data contain many inherent biases. In recent years, advances in both tracking and analytical techniques have meant that, for some taxonomic groups, sufficient numbers of survival estimates are available to allow variation within and among species to be explored. Here we review published estimates of annual adult survival rates in shorebird species across the globe, and construct models to explore the phylogenetic, geographical, seasonal and sex-based variation in survival rates. Models of 295 survival estimates from 56 species show that survival rates calculated from recoveries of dead individuals or from return rates of marked individuals are significantly lower than estimates from mark–recapture models. Survival rates also vary across flyways, largely as a consequence of differences in the genera that have been studied and the analytical methods used, with published estimates from the Americas and from smaller shorebirds (Actitis, Calidris and Charadrius spp.) tending to be underestimated. By incorporating the analytical method used to generate each estimate within a mixed model framework, we provide method-corrected species-specific and genus-specific adult annual survival estimates for 52 species of 15 genera

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    The role of collaboration in the UK green supply chains: an exploratory study of the perspectives of suppliers, logistics and retailers

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    Many companies around the world have started to realise that working alone will not be sufficient in their move towards a greener supply chain (SC). More specifically, recent UK government regulations on implementing strict CO2 reduction encourage SC operators to work collaboratively, in production and logistics or other operations, to achieve their green objectives. In this research, we look at some underlying factors of SC collaboration, focussing on suppliers, logistics and retailers, for the purpose of improving the environmental sustainability of companies’ SCs. To facilitate our study, we conduct case studies in two overseas supplier companies with the aim of providing a better understanding of how green issues imposed by European and UK customers influence the companies’ actions to meet agreed environmental goals. Based on the initial analysis of the case studies, we develop a conceptual framework which indicates that SC collaboration plays an important role in ensuring companies achieve environmental sustainability of their SCs. Subsequently, staff in middle-management and related roles in sixteen companies operating in the UK are interviewed. This allows us to understand their business practices in terms of SC collaboration with their suppliers and buyers to achieve the goal of CO2 reduction. Finally, drawing upon the information from company reports and websites, a number of UK leading retailers’ actions to reduce CO2 emissions are investigated. We develop a conceptual framework of SC collaboration for environmental sustainability to help companies improve their level of collaboration between suppliers and buyers in terms of meeting their environmental objectives. The proposed framework will serve as a base model for the companies using or considering SC collaboration to achieve their environmental agendas, in line with governmental green regulatory requirements
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