22,767 research outputs found

    Recent Results Addressing the KARMEN Timing Anomaly

    Full text link
    Recent resuls from experiments at Fermilab and the Paul Scherrer Institute have constrained the parameter space available for a hypothetical particle Q0Q^0 produced in the decay π+μ+Q0\pi^+ \to \mu^+ Q^0. This decay has been invoked to explain a peculiar feature of an event arrival time distribution observed in the KARMEN neutrino experiment.Comment: 5 pages, 1 figure. Presented at the Conference on the Intersections of Particle and Nuclear Physics (CIPANP 2000), Quebec City, May 200

    Updated Search for Electron Antineutrino Appearance at MiniBooNE

    Full text link
    The MiniBooNE experiment at Fermilab has updated its search for \nu_\mu-bar -> \nu_e-bar oscillations with data collected through May 2011. This represents a statistics increase of 52% over the result published in 2010. The data favor LSND-like oscillations over a background-only hypothesis at the 91.1% confidence level. While the new result remains equally consistent with LSND, the compatibility with the background-only hypothesis is improved. An excess of 38.6 +- 18.5 \nu_e-like events below 475 MeV is observed, consistent with the observation of such an excess in neutrino mode.Comment: 3 pages, 1 figure. Proceedings of the PANIC 11 conference, Cambridge, Mass., July 2011 Corrected typographical error in Table

    A Single-armed Manta-board as a New Diver-controlled Planing Board and Its Use for Underwater Surveys

    Get PDF
    Due to inadequacies of previous underwater towing techniques and the special needs of a recent underwater survey, a modified mania-board technique was developed. With this new technique, the diver holds on to the manta-board with one arm; consequently, the board is referred to as a single-armed manta-board (sam-board). The sam-board proved inexpensive and highly maneuverable, allowing the divers to freely collect samples or record information. Through some experimenting with the board and changing some of the variables, such as rope lengths, towing speeds, etc., a highly efficient towing method can be achieved. Preplanning and strict diving safety procedures must, however, be implemented to assure efficiency. This paper presents the materials, guidelines for board construction, equipment, and preplanning and diving safety procedures necessary for the sam-board towing operation

    An empirical analysis of the welfare magnet debate using the NLSY

    Get PDF
    This paper examines the extent to which differences in welfare generosity across states lead to interstate migration. Using microdata from the National Longitudinal Survey of Youth between 1979 and 1992, we employ a quasi-experimental design that utilizes the categorical eligibility of the welfare system. The "treatment" group consists of all those in the survey who appear eligible to participate in Aid to Families with Dependent Children. The "control" group contains those who are poor but ineligible for other reasons. The pattern of cross-state moves among poor single women with children who are likely to be eligible for benefits (treatment-group members) is compared to the pattern among other poor households. We find little evidence indicating that welfare-induced migration is a widespread phenomenon.

    Evaluation of a metal shear web selectively reinforced with filamentary composites for space shuttle application. Phase 1 summary report: Shear web design development

    Get PDF
    An advanced composite shear web design concept was developed for the Space Shuttle orbiter main engine thrust beam structure. Various web concepts were synthesized by a computer-aided adaptive random search procedure. A practical concept is identified having a titanium-clad + or - 45 deg boron/epoxy web plate with vertical boron/epoxy reinforced aluminum stiffeners. The boron-epoxy laminate contributes to the strength and stiffness efficiency of the basic web section. The titanium-cladding functions to protect the polymeric laminate parts from damaging environments and is chem-milled to provide reinforcement in selected areas. Detailed design drawings are presented for both boron/epoxy reinforced and all-metal shear webs. The weight saving offered is 24% relative to all-metal construction at an attractive cost per pound of weight saved, based on the detailed designs. Small scale element tests substantiate the boron/epoxy reinforced design details in critical areas. The results show that the titanium-cladding reliably reinforces the web laminate in critical edge load transfer and stiffener fastener hole areas

    From an axiological standpoint

    Get PDF
    I maintain that intrinsic value is the fundamental concept of axiology. Many contemporary philosophers disagree; they say the proper object of value theory is final value. I examine three accounts of the nature of final value: the first claims that final value is non‐instrumental value; the second claims that final value is the value a thing has as an end; the third claims that final value is ultimate or non‐derivative value. In each case, I argue that the concept of final value described is either identical with the classical notion of intrinsic value or is not a plausible candidate for the primary concept of axiology

    Fabrication and Electrical Characterization of Fully CMOS Si Single Electron Devices

    Full text link
    We present electrical data of silicon single electron devices fabricated with CMOS techniques and protocols. The easily tuned devices show clean Coulomb diamonds at T = 30 mK and charge offset drift of 0.01 e over eight days. In addition, the devices exhibit robust transistor characteristics including uniformity within about 0.5 V in the threshold voltage, gate resistances greater than 10 G{\Omega}, and immunity to dielectric breakdown in electric fields as high as 4 MV/cm. These results highlight the benefits in device performance of a fully CMOS process for single electron device fabrication.Comment: 7 pages, 7 figure

    A cryocooler for applications requiring low magnetic and mechanical interference

    Get PDF
    A very low-power, low-interference Stirling cryocooler is being developed based on principles and techniques described in several previous publications over the last four years. It differs in several important details from those built previously. It uses a tapered displacer based upon an analytical optimization procedure. The displacer is driven by an auxiliary piston and cylinder (rather than by mechanical linkage) using some of the working fluid itself to provide the driving force. This provides smooth, vibration-free motion, and, more importantly, allows complete mechanical and spatial separation of the cryostat from the pressure-wave generator. Either of two different pressure-wave generators can be used. One is a non-contaminating, unlubricated ceramic piston and cylinder. The other is a compressed-air-operated rubber diaphragm with motor-driven valves to cycle the pressure between appropriate limits

    Wind loads on flat plate photovoltaic array fields (nonsteady winds)

    Get PDF
    Techniques to predict the dynamic response and the structural dynamic loads of flat plate photovoltaic arrays due to wind turbulence were analyzed. Guidelines for use in predicting the turbulent portion of the wind loading on future similar arrays are presented. The dynamic response and the loads dynamic magnification factor of the two array configurations are similar. The magnification factors at a mid chord and outer chord location on the array illustrated and at four points on the chord are shown. The wind tunnel test experimental rms pressure coefficient on which magnification factors are based is shown. It is found that the largest response and dynamic magnification factor occur at a mid chord location on an array and near the trailing edge. A technique employing these magnification factors and the wind tunnel test rms fluctuating pressure coefficients to calculate design pressure loads due to wind turbulence is presented
    corecore