6,627 research outputs found

    Progress report on a new search for free e/3 quarks in the cores of 10(15) - 10(16) eV air showers

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    The Leeds 3 sq m Wilson cloud chamber is being used in a new search for free e/3 quarks close to the axes of 10 to the 15th power - 10 to the 16th power eV air showers. A ratio trigger circuit is used to detect the incidence of air shower cores; the position of the shower center and the axis direction are determined from photographs of current-limited spark chambers. It is thus possible, for the first time, to know where we have looked for quarks in air showers and to select for scanning only those cloud chamber photographs where we have good evidence that the shower axis was close to the chamber. 250 g/sq cm of lead/concrete absorber above the cloud chamber serve to reduce particle densities and make a quark search possible very close to the shower axes. The current status of the search is given

    Current status of MCNP6 as a simulation tool useful for space and accelerator applications

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    For the past several years, a major effort has been undertaken at Los Alamos National Laboratory (LANL) to develop the transport code MCNP6, the latest LANL Monte-Carlo transport code representing a merger and improvement of MCNP5 and MCNPX. We emphasize a description of the latest developments of MCNP6 at higher energies to improve its reliability in calculating rare-isotope production, high-energy cumulative particle production, and a gamut of reactions important for space-radiation shielding, cosmic-ray propagation, and accelerator applications. We present several examples of validation and verification of MCNP6 compared to a wide variety of intermediate- and high-energy experimental data on reactions induced by photons, mesons, nucleons, and nuclei at energies from tens of MeV to about 1 TeV/nucleon, and compare to results from other modern simulation tools.Comment: 4 pages, 3 figures, Proc. 11th Conference on the Intersections of Particle and Nuclear Physics (CIPANP 2012), St. Petersburg, FL, May 28 - June 3, 201

    Development and flight test of a helicopter compact, portable, precision landing system concept

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    An airborne, radar-based, precision approach concept is being developed and flight tested as a part of NASA's Rotorcraft All-Weather Operations Research Program. A transponder-based beacon landing system (BLS) applying state-of-the-art X-band radar technology and digital processing techniques, was built and is being flight tested to demonstrate the concept feasibility. The BLS airborne hardware consists of an add-on microprocessor, installed in conjunction with the aircraft weather/mapping radar, which analyzes the radar beacon receiver returns and determines range, localizer deviation, and glide-slope deviation. The ground station is an inexpensive, portable unit which can be quickly deployed at a landing site. Results from the flight test program show that the BLS concept has a significant potential for providing rotorcraft with low-cost, precision instrument approach capability in remote areas

    The causes of saltland : a case study at Esperance

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    A series of bores on the Esperance Downs Research Station has demonstrated that the groundwater levels change after clearing, and the relatiojnnship between groundwater levels and soil salinity has been emphasised. This pattern of hydrological change leading to soil salinity problems applies widely in the wheatbelt

    A free account or not? Its effect upon information yield in strategic interviews with suspects

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    Asking suspects for a free account (FA) at the start of an interview is considered good practice in a growing number of police organisations, whereas in others it still is not commonplace. This study explored whether interviews with or without such an invitation yielded more information from guilty suspects. Students in safety and security committed a mock crime and were then interviewed using a strategy of gradual disclosure of evidence, in the experimental condition preceded with an FA invitation (n = 20) and without such an invitation in the control condition (n = 17). On average, relatively little information was collected in the FA phase and far more in the subsequent gradual disclosure phase. However, the FA condition yielded seven confessions, four of which were given already in the FA phase. The No FA condition yielded only two confessions. Other differences in yield were not found. These findings indicate that an FA invitation could lead to some relevant and important information, such as a confession, being gathered already at an early stage of an interview, and that such an invitation does not hamper the gathering of further information later in the interview

    Bearing restoration by grinding

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    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed

    Individual and peer comparison open learner model visualisations to identify what to work on next

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    Open learner models (OLM) can support self-regulated learning, collaborative interaction, and navigation in adaptive educational systems. Previous research has found that learners have a range of preferences for learner model visualisation. However, research has focused mainly on visualisations that are available in a single system, meaning that not all visualisations have been compared to each other. We present a study using screen shots of OLM visualisations for individuals and for comparing one's own learner model to the models of other individuals or the group, to define visualisations that students would be able to use to identify their next steps, across a wider range of options
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