43,034 research outputs found

    Spin 1 inversion: a Majorana tensor force for deuteron alpha scattering

    Get PDF
    We demonstrate, for the first time, successful S-matrix to potential inversion for spin one projectiles with non-diagonal Sll′jS^j_{ll'} yielding a TRT_{\rm R} interaction. The method is a generalization of the iterative-perturbative, IP, method. We present a test case indicating the degree of uniqueness of the potential. The method is adapted, using established procedures, into direct observable to potential inversion, fitting σ\sigma, iT11{\rm i}T_{11}, T20T_{20}, T21T_{21} and T22T_{22} for d + alpha scattering over a range of energies near 10 MeV. The TRT_{\rm R} interaction which we find is very different from that proposed elsewhere, both real and imaginary parts being very different for odd and even parity channels.Comment: 7 pages Revtex, 4 ps figure

    The use of Kodak aerochrome infrared color film, type 2443, as a remote sensing tool

    Get PDF
    An infrared color film, Kodak Aerochrome, type 2443, has replaced the 8443 film. The 2443 has lower contrast than the 8443 film, and allows deeper probing into areas that appear as solid black shadows on the 8443 film. The cyan layer of 2443 is approximately 1 1/2 stops slower, at a density of 1.4, than the yellow and magenta emulsion layers

    Locating the pseudogap closing point in cuprate superconductors: absence of entrant or reentrant behavior

    Full text link
    Current descriptions of the pseudogap in underdoped cuprates envision a doping-dependent transition line T∗(p)T^*(p) which descends monotonically towards zero just beyond optimal doping. There is much debate as to the location of the terminal point p∗p^* where T∗(p)T^*(p) vanishes, whether or not there is a phase transition at T∗T^* and exactly how T∗(p)T^*(p) behaves below TcT_c within the superconducting dome. One perspective sees T∗(p)T^*(p) cutting the dome and continuing to descend monotonically to zero at pcrit≈0.19p_{crit} \approx 0.19 holes/Cu −- referred to here as `entrant behavior'. Another perspective derived from photoemission studies is that T∗(p)T^*(p) intersects the dome near pcrit≈0.23p_{crit} \approx 0.23 holes/Cu then turns back below TcT_c, falling to zero again around pcrit≈0.19p_{crit} \approx 0.19 −- referred to here as `reentrant behavior'. By examining thermodynamic data for Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} we show that neither entrant nor reentrant behavior is experimentally supported. Rather, pcrit≈0.19p_{crit} \approx 0.19 sharply delimits the pseudogap regime and for p<0.19p < 0.19 the pseudogap is always present, independent of temperature. Similar results are found for Y0.8_{0.8}Ca0.2_{0.2}Ba2_2Cu3_3O7−δ_{7-\delta}. For both materials T∗(p)T^*(p) is not a temperature but a crossover scale, ≈E∗(p)/2kB\approx E^*(p)/2k_B, reflecting instead the underlying pseudogap energy E∗(p)E^*(p) which vanishes as p→0.19p \rightarrow 0.19.Comment: 20 Pages, 9 Figures, in press Phys. Rev.

    Velocity statistics in excited granular media

    Full text link
    We present an experimental study of velocity statistics for a partial layer of inelastic colliding beads driven by a vertically oscillating boundary. Over a wide range of parameters (accelerations 3-8 times the gravitational acceleration), the probability distribution P(v) deviates measurably from a Gaussian for the two horizontal velocity components. It can be described by P(v) ~ exp(-|v/v_c|^1.5), in agreement with a recent theory. The characteristic velocity v_c is proportional to the peak velocity of the boundary. The granular temperature, defined as the mean square particle velocity, varies with particle density and exhibits a maximum at intermediate densities. On the other hand, for free cooling in the absence of excitation, we find an exponential velocity distribution. Finally, we examine the sharing of energy between particles of different mass. The more massive particles are found to have greater kinetic energy.Comment: 27 pages, 13 figures, to appear in Chaos, September 99, revised 3 figures and tex

    Study of a signal processor employing a synthetic phase isolator

    Get PDF
    Evaluation of signal data processor employing synthetic phase isolator techniqu

    Entanglement enhanced atomic gyroscope

    Full text link
    The advent of increasingly precise gyroscopes has played a key role in the technological development of navigation systems. Ring-laser and fibre-optic gyroscopes, for example, are widely used in modern inertial guidance systems and rely on the interference of unentangled photons to measure mechanical rotation. The sensitivity of these devices scales with the number of particles used as 1/N1/ \sqrt{N}. Here we demonstrate how, by using sources of entangled particles, it is possible to do better and even achieve the ultimate limit allowed by quantum mechanics where the precision scales as 1/N. We propose a gyroscope scheme that uses ultra-cold atoms trapped in an optical ring potential.Comment: 19 pages, 2 figure

    A Method for the Study of Human Factors in Aircraft Operations

    Get PDF
    A method for the study of human factors in the aviation environment is described. A conceptual framework is provided within which pilot and other human errors in aircraft operations may be studied with the intent of finding out how, and why, they occurred. An information processing model of human behavior serves as the basis for the acquisition and interpretation of information relating to occurrences which involve human error. A systematic method of collecting such data is presented and discussed. The classification of the data is outlined

    Pasteurization of cream for buttermaking

    Get PDF
    In some European countries the pasteurization of cream for buttermaking is extensively practiced. Butter manufacturers in the United States have long recognized that this is a desirable procedure and they have written numerous letters to the experiment stations seeking information regarding it. In many cases it has been more or less difficult to answer these inquiries because of the comparatively small amount of experimental work which has been done along this line. The purpose of the experiments herein reported was to determine the value of pasteurization to those engaged in the manufacture of butter. In this connection the effect of pasteurization on the flavor of the butter, on the keeping quality, on the body, on the chemical composition, and on the mechanical losses was considered and an effort was made to determine the relative merits of the various methods of pasteurization

    Pool boiling on modified surfaces using R-123

    Get PDF
    This article has been made available through the Brunel Open Access Publishing Fund.Saturated pool boiling of R-123 was investigated for five horizontal copper surfaces modified by different treatments, namely, an emery-polished surface, a fine sandblasted surface, a rough sandblasted surface, an electron beam-enhanced surface, and a sintered surface. Each 40-mm-diameter heating surface formed the upper face of an oxygen-free copper block, electrically heated by embedded cartridge heaters. The experiments were performed from the natural convection regime through nucleate boiling up to the critical heat flux, with both increasing and decreasing heat flux, at 1.01 bar, and additionally at 2 bar and 4 bar for the emery-polished surface. Significant enhancement of heat transfer with increasing surface modification was demonstrated, particularly for the electron beam-enhanced and sintered surfaces. The emery-polished and sandblasted surface results are compared with nucleate boiling correlations and other published data. © 2014 Syed W. Ahmad, John S. Lewis, Ryan J. McGlen, and Tassos G. Karayiannis Published with license by Taylor & Francis
    • …
    corecore