698 research outputs found

    Arc termination cracks in Inconel 718 and Incoloy 903

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    The welding of the nickel base, heat resistant alloys that are used extensively for welded Shuttle engine components revealed solidification cracking characteristics at weld termination points. If not detected and removed, these crater cracks may cause costly component failure. To better understand this characteristic, welding termination techniques were studied and methods developed to eliminate crater cracks. It was determined that weld termination solidification cracking can be eliminated by controlled decrease of welding current, welding voltage, wire feed, and travel speed

    In-situ measurements of wall moisture in a historic building in response to the installation of an impermeable floor

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    When impermeable ground bearing slabs are installed in old buildings without a damp-proof course, it is a common belief of conservation practitioners that ground moisture will be ‘driven’ up adjacent walls by capillary action. However, there is limited evidence to test this hypothesis. An experiment was used to determine if the installation of a vapour-proof barrier above a flagstone floor in a historic building would increase moisture content levels in an adjacent stone rubble wall. This was achieved by undertaking measurements of wall, soil and atmospheric moisture content over a 3-year period. Measurements taken using timber dowels showed that the moisture content within the wall did not vary in response to wall evaporation rates and did not increase following the installation of a vapour-proof barrier above the floor. This indicates that the moisture levels in the rubble wall were not influenced by changes in the vapour-permeability of the floor

    The Direction of Neurite Growth in a Weak DC Electric Field Depends on the Substratum: Contributions of Adhesivity and Net Surface Charge

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    AbstractWe investigated the influence of the growth surface on the direction ofXenopusspinal neurite growth in the presence of a dc electric field of physiological magnitude. The direction of galvanotropism was determined by the substratum; neurites grew toward the negative electrode (cathode) on untreated Falcon tissue culture plastic or on laminin substrata, which are negatively charged, but neurites growing on polylysine, which is positively charged, turned toward the positive electrode (anode). Growth was oriented randomly on all substrata without an electric field. We tested the hypothesis that the charge of the growth surface was responsible for reversed galvanotropism on polylysine by growing neurons on tissue culture dishes with different net surface charges. Although neurites grew cathodally on both Plastek substrata, the frequency of anodal turning was greater on dishes with a net positive charge (Plastek C) than on those with a net negative charge (Plastek M). The charge of the growth surface therefore influenced the frequency of anodal galvanotropism but a reversal in surface charge was insufficient to reverse galvanotropism completely, possibly because of differences in the relative magnitude of the substratum charge densities. The influence of substratum adhesion on galvanotropism was considered by growing neurites on a range of polylysine concentrations. Growth cone to substratum adhesivity was measured using a blasting assay. Adhesivity and the frequency of anodal turning were graded over the range of polylysine concentrations (0 = 0.1 < 1 < 10 = 100 μg/ml). The direction of neurite growth in an electric field is therefore influenced by both substratum charge and growth cone-to-substratum adhesivity. These data are consistent with the idea that spatial or temporal variation in the expression of adhesion molecules in embryos may interact with naturally occurring electric fields to enhance growth cone pathfinding

    Review of the integrity of a Self Administered Motivational Instrument

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    BackgroundMotivational interviewing (MI) was developed by Miller and Rollnick as an evidence-based counselling approach for use in supporting people with alcohol problems. Over the years the principles and spirit of MI have been reviewed and fine-tuned and the approach has been embraced by practitioners worldwide and across fields.Since 2001 a number of instruments have been designed to evaluate the fidelity of MI practice. For the purposes of this study, one such instrument is used to assess a self-administered motivational instrument, known as the SAMI, which takes the interviewer role.ObjectivesThe SAMI is evaluated against the MITI 3.1.1, which is designed to assess the extent to which MI interventions perform on five global dimensions. These are evocation, collaboration, autonomy/support, direction and empathy.DesignThe SAMI was assembled based on the principles and spirit of MI, problem solving and goal-setting. The targeted behaviour changes were student learning styles and approaches to study.SettingThe SAMI was distributed, completed and submitted electronically via the university virtual learning environment.ParticipantsThirty three mature students of a university which delivered online nursing programme were invited to complete the SAMI. Of these, 25 submitted completed transcripts.MethodsTranscripts of a sample of six completed SAMIs were assessed by a group of teachers and researchers with experience in the use and evaluation of MI, using five-point Likert scales to assess the SAMI on the five dimensions.ResultsOverall, an average score exceeding 4.5 was attained across the five dimensions. Conventionally, such a score is recognised as competency in MI. However, on one dimension (empathy), the rating was three.ConclusionsThis current research confirms that global principles have been observed in the online delivery of MI using the SAMI to probe approaches to study

    Nanoelectromechanical Resonator Arrays for Ultrafast, Gas-Phase Chromatographic Chemical Analysis

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    Miniaturized gas chromatography (GC) systems can provide fast, quantitative analysis of chemical vapors in an ultrasmall package. We describe a chemical sensor technology based on resonant nanoelectromechanical systems (NEMS) mass detectors that provides the speed, sensitivity, specificity, and size required by the microscale GC paradigm. Such NEMS sensors have demonstrated detection of subparts per billion (ppb) concentrations of a phosphonate analyte. By combining two channels of NEMS detection with an ultrafast GC front-end, chromatographic analysis of 13 chemicals was performed within a 5 s time window

    Modelling wave-current interactions off the east coast of Scotland

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    Densely populated coastal areas of the North Sea are particularly vulnerable to severe wave conditions, which overtop or damage sea-defences leading to dangerous flooding. Around the shallow southern North Sea, where the coastal margin is low-lying and population density is high, oceanographic modelling has helped to develop forecasting systems to predict flood risk. However coastal areas of the deeper northern North Sea are also subject to regular storm damage but there has been little or no effort to develop coastal wave models for these waters. Here we present a high spatial resolution model of northeast Scottish coastal waters, simulating waves and the effect of tidal currents on wave propagation, driven by global ocean tides, far-field wave conditions, and local air pressure and wind stress. We show that the wave- current interactions and wave-wave interactions are particularly important for simulating the wave conditions close to the coast at various locations. The model can simulate the extreme conditions experienced when high (spring) tides are combined with sea-level surges and large Atlantic swell. Such a combination of extremes represents a high risk for damaging conditions along the Scottish coast

    AAC W1876 hard red spring wheat

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    AAC W1876 hard red spring wheat (Triticum aestivum L.) has grain yield and time to maturity within the range of the check cultivars: Katepwa, Laura, Lillian, Carberry, and CDC Kernen. AAC W1876 has an awned spike, a low lodging score indicative of strong straw, and a short plant stature typical of a semidwarf wheat. AAC W1876 expressed resistance to prevalent races of leaf rust, moderate resistance to stem rust, intermediate resistance to fusarium head blight, yellow rust, common bunt, and loose smut. Compared to the Canada Western Red Spring check cultivars, AAC W1876 had improved flour yield and lower flour ash. AAC W1876 is eligible for grades of Canada Western Red Spring

    AAC Penhold Canada Prairie Spring Red Wheat

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    AAC Penhold, an awned hard red spring wheat (Triticum aestivum L.) cultivar, yielded significantly more grain than 5700PR while maturing 2 days earlier, and 7.5 cm shorter stature. The seed size was significantly larger than 5700PR and 5701PR, with a test weight significantly heavier than both checks. AAC Penhold expressed resistance to prevalent races of leaf rust and common bunt, and moderate resistance to fusarium head blight and stem rust. AAC Penhold had higher grain and flour protein than the checks and improved Hagberg Falling Number, amylograph viscosity, and water absorption. AAC Penhold is eligible for grades of the market class, Canada Prairie Spring Red wheat
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