6,389 research outputs found

    Quadrupolar quantum criticality on a fractal

    Get PDF
    We study the ground state ordering of quadrupolar ordered S=1S=1 magnets as a function of spin dilution probability pp on the triangular lattice. In sharp contrast to the ordering of S=1/2S=1/2 dipolar N\'eel magnets on percolating clusters, we find that the quadrupolar magnets are quantum disordered at the percolation threshold, p=pp=p^*. Further we find that long-range quadrupolar order is present for all p<pp<p^* and vanishes first exactly at pp^*. Strong evidence for scaling behavior close to pp^* points to an unusual quantum criticality without fine tuning that arises from an interplay of quantum fluctuations and randomness

    Provisional specification for satellite time in a geomagnetic environment

    Get PDF
    Satellites in geosynchronous orbit were experiencing operational anomalies. These anomalies are believed to be due to the environment charging the spacecraft surfaces to a point where discharges occur. In designing future satellites for long term operation at geosynchronous altitude, it is important that designers have a specification that will give the total time per year, the particle flux density and particle energies that their satellites can be expected to encounter in these substorm environmental conditions. The limited data currently available on the environmental conditions are used to generate the provisional specification given in this report

    Productivity at the Post: its Drivers and its Distribution

    Get PDF
    We study the economic, financial and distributional performance of the United States Postal Service subsequent to its 1971 reorganization. We investigate the economic drivers of productivity change (technical change, change in cost efficiency, and scale economies), and the distribution of the financial benefits of productivity change (consumers of postal services, postal employees and other resource suppliers, and residual claimants). We find improvements in technology to have been the main driver of, and diseconomies of scale to have been the main drag on, productivity change. We find labor to have been the main beneficiary, and consumers of postal services the main losers, from postal reorganization.

    Development of a non-linear simulation for generic hypersonic vehicles - ASUHS1

    Get PDF
    A nonlinear simulation is developed to model the longitudinal motion of a vehicle in hypersonic flight. The equations of motion pertinent to this study are presented. Analytic expressions for the aerodynamic forces acting on a hypersonic vehicle which were obtained from Newtonian Impact Theory are further developed. The control surface forces are further examined to incorporate vehicle elastic motion. The purpose is to establish feasible equations of motion which combine rigid body, elastic, and aeropropulsive dynamics for use in nonlinear simulations. The software package SIMULINK is used to implement the simulation. Also discussed are issues needing additional attention and potential problems associated with the implementation (with proposed solutions)

    Using Fieldwork, GIS and DEA to Guide Management of Urban Stream Health

    Get PDF

    Testing the Product Test

    Get PDF
    The product test asks the product of a quantity index number and a price index number to equal the corresponding value change. The literature treats the product test as being so important that it is used to identify acceptable index number pairs, and to construct implicit index numbers when an otherwise desirable pair fails the test. We treat the product test as a hypothesis to be tested, and we provide an empirical application.

    Provisional specification for satellite time in a geomagnetic substorm environment

    Get PDF
    Satellites in geosynchronous orbit have been experiencing operational anomalies. These anomalies are believed to be due to the environment charging the spacecraft surfaces to a point where discharges occur. In designing future satellites for long term operation at geosynchronous altitude, it is important that designers have a specification that will give the total time per year, the particle flux density, and particle energies that their satellites can be expected to encounter in these substorm environmental conditions. The limited data currently available on the environmental conditions was used to generate the provisional specification given

    Automatic Segmentation and Recognition of Bank Cheque Fields

    Get PDF
    This paper describes a novel method for automatically segmenting and recognizing the various information fields present on a bank cheque. The uniqueness of our approach lies in the fact that it doesn't necessitate any prior information and requires minimum human intervention. The extraction of segmented fields is accomplished by means of a connectivity based approach. For the recognition part, we have proposed four innovative features, namely; entropy, energy, aspect ratio and average fuzzy membership values. Though no particular feature is pertinent in itself but a combination of these is used for differentiating between the fields. Finally, a fuzzy neural network is trained to identify the desired fields. The system performance is quite promising on a large dataset of real and synthetic cheque images
    corecore