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Now showing items 1 - 16 of 82

  • ESTIMATING ANIMAL LOCATIONS FROM CALL INTERFEROMETRY

    Estimating Animal Locations from Call Interferometry Bat detectors and recorders are an invaluable tool for monitoring the behaviour of bats at local scales. Fine scale monitoring of the movements of bats is possible with other techniques but these are expensive (radar) or time consuming (visual observations, IR video). Bats emit social and echo-location calls. Off-the-shelf wildlife sound recorders have been used previously to triangulate the position of animal species from their calls, using GPS to synchronise timing. Tracking the movements of flying species by triangulation would need microphones to be mounted above-ground. A more intuitive measure of behaviour around objects and landscape features is the angle from a fixed origin to the source of the call. This can be measured in one or more dimensions by interferometry. We have validated two methods of estimating the angle to a call. Simple sinusoidal signals can be interpreted to deduce the angle to the call by comparing the difference in phase recorded at each microphone calculated from the Discrete Fourier Transforms of the signals. Animal calls are usually modulated in their amplitude and frequency, precluding phase estimation from Fourier analysis. The angle to the source of the call can, however, can be estimated from the instantaneous phase and instantaneous frequency, derived from the analytic form of the signal, which we calculated with a Hilbert transform. Sinusoidal signals were validated in a laboratory test using an ultrasonic emitter to generate simulated calls. Frequency and amplitude modulated signals were validated by recordings of soprano pipistrelles (Pipistrellus pigmaeus) exiting a roost and flying over the interferometer. The calls were distorted by interference from reflections from the wall of the roost, but the angle could be measured to an accuracy of 2º, and a positional accuracy of 260 mm (at a height of 7 m). Calls without the echo showed a much better accuracy. A one-dimensional form requires two microphones. Two and three dimensional forms can be created by adding additional microphones mounted orthogonally to a reference microphone that is common to each sound recorder. Height estimation is possible by triangulating the angles produced by two or more interferometers.
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  • Dislocation Interactions in Olivine Revealed by HR-EBSD

    Wallis, David   Hansen, Lars N.   Ben Britton, T.   Wilkinson, Angus J.  

    Interactions between dislocations potentially provide a control on strain rates produced by dislocation motion during creep of rocks at high temperatures. However, it has been difficult to establish the dominant types of interactions and their influence on the rheological properties of creeping rocks due to a lack of suitable observational techniques. We apply high-angular resolution electron backscatter diffraction to map geometrically necessary dislocation (GND) density, elastic strain, and residual stress in experimentally deformed single crystals of olivine. Short-range interactions are revealed by cross correlation of GND density maps. Spatial correlations between dislocation types indicate that noncollinear interactions may impede motion of proximal dislocations at temperatures of 1000 degrees C and 1200 degrees C. Long-range interactions are revealed by autocorrelation of GND density maps. These analyses reveal periodic variations in GND density and sign, with characteristic length scales on the order of 1-10m. These structures are spatially associated with variations in elastic strain and residual stress on the order of 10(-3) and 100MPa, respectively. Therefore, short-range interactions generate local accumulations of dislocations, leading to heterogeneous internal stress fields that influence dislocation motion over longer length scales. The impacts of these short- and/or long-range interactions on dislocation velocities may therefore influence the strain rate of the bulk material and are an important consideration for future models of dislocation-mediated deformation mechanisms in olivine. Establishing the types and impacts of dislocation interactions that occur across a range of laboratory and natural deformation conditions will help to establish the reliability of extrapolating laboratory-derived flow laws to real Earth conditions.
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  • WIRELESS POWER TRANSFER USING A MICROWAVE SIGNAL

    A wireless power source including a microwave receiver, a matching network, and a transducer. The microwave receiver receives a microwave signal having a carrier frequency. The matching network receives a signal having the carrier frequency and a switched frequency and removes the carrier frequency such that the matching network outputs a switched signal at the switched frequency. The transducer is configured to receive the switched signal and output a DC voltage.
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  • IMPACT DETECTION SYSTEM

    An impact detection system is disclosed for detecting and identifying an object colliding with a vehicle. The impact detection system comprises a sensor arrangement arranged to measure a characteristic of an impact of the object against the vehicle, a trigger determiner associated with the sensor arrangement for determining whether the characteristic of the 5 impact is greater than a predefined threshold value, and an image capturing device arranged to capture an image of the object. The system is arranged to automatically make the captured image available for inspection in response to the trigger determiner determining that the characteristic of the impact is greater than the predefined threshold value so that the object in the image can be identified substantially in real-time.
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  • Dislocation Interactions in Olivine Revealed by HR-EBSD

    Wallis, David   Hansen, Lars N.   Britton, T. Ben   Wilkinson, Angus J.  

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  • Unique metabolites protect earthworms against plant polyphenols.

    Liebeke, Manuel   Strittmatter, Nicole   Fearn, Sarah   Morgan, A John   Kille, Peter   Fuchser, Jens   Wallis, David   Palchykov, Vitalii   Robertson, Jeremy   Lahive, Elma   Spurgeon, David J   McPhail, David   Takats, Zoltan   Bundy, Jacob G  

    All higher plants produce polyphenols, for defence against above-ground herbivory. These polyphenols also influence the soil micro- and macro-fauna that break down plant leaf litter. Polyphenols therefore indirectly affect the fluxes of soil nutrients and, ultimately, carbon turnover and ecosystem functioning in soils. It is unknown how earthworms, the major component of animal biomass in many soils, cope with high-polyphenol diets. Here, we show that earthworms possess a class of unique surface-active metabolites in their gut, which we term 'drilodefensins'. These compounds counteract the inhibitory effects of polyphenols on earthworm gut enzymes, and high-polyphenol diets increase drilodefensin concentrations in both laboratory and field populations. This shows that drilodefensins protect earthworms from the harmful effects of ingested polyphenols. We have identified the key mechanism for adaptation to a dietary challenge in an animal group that has a major role in organic matter recycling in soils worldwide. =20
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  • 21st annual Whitley Awards

    Wallis, David  

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  • 19th annual Whitley Awards

    Wallis, David  

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  • Standby Person for Electrical Tasks and Rescue Guidelines for Electrical Incident Victims

    Jamil, Shahid   Gammon, Tammy   Wallis, David   Fontaine, Michael D.  

    National Fire Protection Association (NFPA) 70E, Standard for Electrical Safety in the Workplace, requires that employees exposed to electric shock hazards be trained in methods of releasing persons being shocked and unable to let-go of live circuits. NFPA 70E also requires employer-designated first responders to be trained in first aid, cardiopulmonary resuscitation (CPR), and automated external defibrillator (AED) use, if provided. Occupational Safety and Health Administration (OSHA) 29 Code of Federal Regulations (CFR) 1910.151 might be interpreted as requiring first aid treatment within the first few minutes of injury (3-4 min to avoid permanent impairment or death), and qualified persons to be trained in first aid, CPR, and AED use. NFPA 70E's Informative Annex I checklist on job briefing and planning asks is a standby person required and is the person CPR trained? Informational Note 2 for Section 110.1(G) on risk assessment procedures recognizes a possible need to identify the electrical tasks that require a second person (standby person), and the necessary equipment and training for a second person. In OSHA's standard for electric power generation, transmission, and distribution, 29 CFR 1910.269(1)(2) requires a second person when nonroutine switching is performed on systems above 600 V. This paper discusses the standby person's qualifications and responsibilities, and what electrical tasks may require a standby person. General guidelines on the rescue of victims injured in electrical incidents are also included.
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  • AN IMPROVED HERBICIDE COMPOSITION

    A herbicidal composition, said composition including a glyphosate salt, fulvic acid and a surfactant blend, said surfactant blend including the following components, a salt of a sulphated alkoxylated alcohol, a C10-C18 alcohol, a water miscible organic solvent capable of dissolving component (b), one or more solubilizing agents and water.
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  • Recent loss of floating ice and the consequent sea level contribution (vol 39, L17503, 2012)

    Shepherd, Andrew   Wingham, Duncan   Wallis, David   Giles, Katharine   Laxon, Seymour   Sundal, Aud Venke  

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  • Fault weakening across the frictional-viscous transition zone, Karakoram Fault Zone, NW Himalaya

    Wallis, David   Phillips, Richard J.   Lloyd, Geoffrey E.  

    [1] Exhumed fault rocks formed in the frictional-viscous transition zone (FVTZ) provide test material that can be used to assess the strength of natural fault zones. In the Karakoram Fault Zone (KFZ), such rocks contain evidence of several long-term weakening mechanisms associated with reduced coefficients of friction (<0.4). The Nubra, Tangtse, and Arganglas strands of the KFZ are focused along metavolcano-sedimentary formations indicating weakness relative to the bounding granitoids. Synkinematic retrogression suggests that reaction softening has weakened the margins of granitoids along the Nubra and Tangtse strands and the Nubra Formation within the Nubra strand. The resultant phyllosilicates have formed well-developed interconnected weak layers within phyllonites and granitic mylonites. Micaceous foliae with increased proportions of opaque minerals in granitic mylonites suggest that fluid-assisted diffusive mass transfer aided deformation within the Nubra and Tangtse strands. Microstructures within Nubra strand phyllonites suggest that frictional-viscous flow accommodated deformation at low shear stresses in the FVTZ. Multiple generations of veining within each strand indicate overpressured pore fluids within the fault zone across a range of depths. Active springs and travertines along the fault indicate ongoing suprahydrostatic fluid flow within the KFZ. Despite such evidence for weakening mechanisms, the KFZ is currently locked and most likely generates moment magnitude 7.5+ earthquakes. Evidence for multiple fault weakening mechanisms reduces potential for shear heating within the KFZ and suggests that the long-term strength of the lithosphere must reside below the depth of penetration of the fault.
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  • APPARATUS FOR AND METHOD OF WAFER GRINDING

    An apparatus (10) for wafer grinding includes sensors (38) and a spectral analyzer to perform a spectral analysis of light received by the sensors (38) during grinding of a semiconductor wafer (12). Based on the spectral analysis, the grinding process is stopped or the force applied to the semiconductor wafer is modified. This in situ monitoring decreases breakage and overheating of the semiconductor wafer (12).
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  • AUXILIARY COMPOSITIONS

    An auxiliary composition for use in combination with a pesticide or herbicide composition, the auxiliary composition comprising: (a) a salt of a sulphated alkoxylated alcohol such as sodium lauryl ether sulphate; (b) a C10 - C18 alcohol such as lauryl alchohol; (c) a water miscible organic solvent capable of dissolving component (b) such as EDTA; (d) one or more solubilizing agents capable of solubilizing the pesticide or herbicide such as sodium xylene sulphonate and ethanol; and (e) water, optionally with a chelating or sequestering agent and/or a plant nutrient.
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  • APPARATUS AND METHOD FOR MEASURING TOOL DEGRADATION

    A machining apparatus (10) comprises a material removing tool (12) movably mounted for removing material from a workpiece (14); means for illuminating (42, 54) a sample area upon a tool surface (34) with excitation radiation; means for receiving (42, 54) sample light emitted from the sample area; a spectral analyzer (54) for performing a spectral analysis of the sample light received; and means for determining (60) the condition of the tool at the sample area from the spectral analysis of the sample light. The wear of the tool (12) is determined as such a condition. Operation parameters of the machining apparatus (10) are adjusted according to the determined wear. An example application is a wafer dicing tool.
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  • Low-Temperature Plasticity in Olivine:Grain Size,Strain Hardening,and the Strength of the Lithosphere

    Hansen, Lars N.   Kumamoto, Kathryn M.   Thom, Christopher A.   Wallis, David   Durham, William B.   Goldsby, David L.   Breithaupt, Thomas   Meyers, Cameron D.   Kohlstedt, David L.  

    Plastic deformation of olivine at relatively low temperatures (i.e., low-temperature plasticity) likely controls the strength of the lithospheric mantle in a variety of geodynamic contexts. Unfortunately, laboratory estimates of the strength of olivine deforming by low-temperature plasticity vary considerably from study to study, limiting confidence in extrapolation to geological conditions. Here we present the results of deformation experiments on olivine single crystals and aggregates conducted in a deformation-DIA at confining pressures of 5 to 9 GPa and temperatures of 298 to 1473 K. These results demonstrate that, under conditions in which low-temperature plasticity is the dominant deformation mechanism, fine-grained samples are stronger at yield than coarse-grained samples, and the yield stress decreases with increasing temperature. All samples exhibited significant strain hardening until an approximately constant flow stress was reached. The magnitude of the increase in stress from the yield stress to the flow stress was independent of grain size and temperature. Cyclical loading experiments revealed a Bauschinger effect, wherein the initial yield strength is higher than the yield strength during subsequent cycles. Both strain hardening and the Bauschinger effect are interpreted to result from the development of back stresses associated with long-range dislocation interactions. We calibrated a constitutive model based on these observations, and extrapolation of the model to geological conditions predicts that the strength of the lithosphere at yield is low compared to previous experimental predictions but increases significantly with increasing strain. Our results resolve apparent discrepancies in recent observational estimates of the strength of the oceanic lithosphere.
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