4,145 research outputs found

    Veering triangulations admit strict angle structures

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    Agol recently introduced the concept of a veering taut triangulation, which is a taut triangulation with some extra combinatorial structure. We define the weaker notion of a "veering triangulation" and use it to show that all veering triangulations admit strict angle structures. We also answer a question of Agol, giving an example of a veering taut triangulation that is not layered.Comment: 15 pages, 9 figure

    Rapeseed. 2. Insect control

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    RAPESEED crops are highly susceptible to attack from a number of insects and, in most cases, some crop protection measures will be necessary to achieve satisfactory yields. This article discusses the insects that have been a problem in rapeseed crops in Western Australia to date

    Advances in cold sintering : Improving energy consumption and unlocking new potential in component manufacturing

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    Ceramics are traditionally sintered at high temperatures (~80% melting temperature (Tm)). There are numerous incentives to reduce processing temperature: the reduction in processing energy; integration of polymeric and non-noble metals; greater control of microstructure and final component geometries. ‘Cold sintering’ has been developed as a novel method of densification which uses a transient liquid phase, pressure and heat to achieve dense ceramics. This review explores the process of cold sintering and its potential to densify various ceramic materials and components at low temperatures (<300°C), primarily describing recent results at The University of Sheffield, UK

    Teaching Foundational Aquatic Skills to Children in Open Water Environments

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    Learning to swim in a swimming pool might not prepare water competence sufficiently for different aquatic environments. The aim of this study was to assess the effectiveness of teaching children water safety knowledge and skills in open water environments (i.e., harbor, river, and surf). The aquatic knowledge and skills of 98 children (7-11 years old) were tested in a swimming pool before, immediately after, and three months after receiving a three-day intensive education program. At pre-test, typically fewer than 50% of children achieved a high level of water safety competence. After the program, competency in each of the six tasks assessed had increased with up to 80% of participants completing the tasks unassisted. Three-month retention of these skills was generally high (i.e., competency levels were either maintained or improved). A key challenge for future research will be to untangle the influences of maturation, order effects, and the open water education

    On the poverty of a priorism: technology, surveillance in the workplace and employee responses

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    Many debates about surveillance at work are framed by a set of a priori assumptions about the nature of the employment relationship that inhibits efforts to understand the complexity of employee responses to the spread of new technology at work. In particular, the debate about the prevalence of resistance is hamstrung from the outset by the assumption that all apparently non-compliant acts, whether intentional or not, are to be counted as acts of resistance. Against this background this paper seeks to redress the balance by reviewing results from an ethnographic study of surveillance-capable technologies in a number of British workplaces. It argues for greater attention to be paid to the empirical character of the social relations at work in and through which technologies are deployed and in the context of which employee responses are played out

    Apiezon L-type grease coating of 8-”m Nuclepore Polycarbonate coarse filters used in GENT aerosol sampling units.

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    Coarse stage Nuclepore filters used in GENT aerosol sampling units were coated with a thin film of Apiezon L-type grease in order to minimise the loss of particles on the filters due to 'bounce off'. Originally Freon was used as the solvent to dissolve the Apiezon grease in the coating process. Because of the environmental impact, Freon was discontinued and replaced with Fluorinert. Apiezon grease did not dissolve freely in the Fluorinert and it was replaced by Fomblin grease in 1995. This increased production costs and coated Nuclepore coarse filters ceased production in 2004. Users were concerned that their stocks of coated Nuclepore filters were diminishing and as no alternative supply was available the feasibility of coating the coarse filters in house needed to be investigated. This report describes experiments conducted at ANSTO and the results obtained during the investigation of the coating process under laboratory conditions. Apiezon grease and Toluene were used in this process. Experiments were based on the procedure proposed by Prof P. Hopke and Dr A. Markwitz [1] with modification to this technique to increase the uniformity of the grease layer across the filter surface and to achieve approximately 100 ”g of Apiezon grease per filter

    Seismological and geotechnical aspects of the Mw=6.3 l’Aquila earthquake in central Italy on 6 April 2009

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    The L’Aquila earthquake occurred on April 6 2009 at 03:32:39 local time. The earthquake (Mw=6.3) was located in the central Italy region of Abruzzo. Much of the damage occurred in the capital city of L’Aquila, a city of approximate population 73000, although many small villages in the surrounding region of the middle Aterno river valley were also significantly damaged. In the weeks following the earthquake, the Geo-Engineering Extreme Events Reconnaissance (GEER) international team, comprised of members from different European countries and the U.S., was assembled to provide post-earthquake field reconnaissance. The GEER team focused on the geological, seismological, and geotechnical engineering aspects of the event. We describe the principal seismological findings related to this earthquake including moment tensors of the main shock and two triggered events, the aftershock pattern and its variation with time, tectonic deformations associated with the main shock, surface fault rupture, and the inferred fault rupture plane. We describe damage patterns on a village-to-village scale and on a more local scale within the city of L’Aquila. In many cases the damage patterns imply site effects, as neighbouring villages on rock and soil had significantly different damage intensities (damage more pronounced on softer sediments). The April 6 mainshock was the best-recorded event to date in Italy. We present metadata related to the recording sites and then present preliminary comparisons of the data to GMPEs. Those comparisons support the notion of faster distance attenuation in Italy relative to the average for active regions as reflected in NGA GMPEs. Several incidents of ground failure are then discussed, including a number of rockfalls and minor landslides. Perhaps the most significant incidents of ground failure occurred at Lake Sinizzo, for which we describe a number of slumps and spreads around the lake perimeter. This is documented using field observations as well as LIDAR and bathymetric data
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