983 research outputs found

    A Practical Quantum Bit Commitment Protocol

    Get PDF
    In this paper, we introduce a new quantum bit commitment protocol which is practically secure against entanglement attacks. A general cheating strategy is discussed and shown to be practically ineffective against the proposed approach

    Iron-Enhanced Swale Ditch Checks for Phosphorus Retention

    Get PDF
    Minnesota Department of Transportatio

    Survey of Stormwater BMP Maintenance Practices

    Get PDF
    Many stormwater management manuals and guidance documents have stated the importance and estimated frequency of maintenance for stormwater best management practices (BMPs), but few have documented the actual frequency and intensity of maintenance required to maintain a desired level of performance and efficiency. Increased attention to mass balance, numerical goals, total maximum daily loads (TMDLs), and non-degradation requirements has created the need for more emphasis on BMP maintenance in order to meet permitting and reporting requirements. The purpose of this paper is to advance short and long-term maintenance considerations so as to develop more realistic maintenance plans. To do so, we conducted a national literature search for maintenance costs and developed, distributed, analyzed the results of a detailed municipal public works survey. The specific goals of the survey were to identify and inventory stormwater BMP O&M efforts and costs. Survey questionnaires were sent to 106 cities with 28 responses received. The survey related to the following topics: number of BMPs in the city, frequency of BMP inspections, average staff-hours spent per routine inspection/maintenance, complexity of BMP maintenance, most frequent causes of performance deterioration within BMPs, and cost of non-routine maintenance activities. The results of the survey revealed that most (89%) cities perform routine maintenance once per year or less. Staff-hours per year ranged from one to four hours for most stormwater BMPs and but were significantly more for rain gardens (one to sixteen hours per year) and wetlands (one to nine hours per year). The most common causes of performance deterioration were sediment buildup and litter/debris for most stormwater BMPs. Respondents indicated that the removal of accumulated sediment incurred the largest cost of all BMP maintenance activities

    Weather in stellar atmosphere: the dynamics of mercury clouds in alpha Andromedae

    Full text link
    The formation of long-lasting structures at the surfaces of stars is commonly ascribed to the action of strong magnetic fields. This paradigm is supported by observations of evolving cool spots in the Sun and active late-type stars, and stationary chemical spots in the early-type magnetic stars. However, results of our seven-year monitoring of mercury spots in non-magnetic early-type star alpha Andromedae show that the picture of magnetically-driven structure formation is fundamentally incomplete. Using an indirect stellar surface mapping technique, we construct a series of 2-D images of starspots and discover a secular evolution of the mercury cloud cover in this star. This remarkable structure formation process, observed for the first time in any star, is plausibly attributed to a non-equilibrium, dynamical evolution of the heavy-element clouds created by atomic diffusion and may have the same underlying physics as the weather patterns on terrestrial and giant planets.Comment: 10 pages, 2 figures; to be published in Nature Physic

    Modeling Sustainable Traffic Behavior: Avoiding Congestion at a Stationary Bottleneck

    Get PDF
    Sustainable traffic behaviour is increasing in importance as traffic volume rises due to population growth. In this paper, a model for traffic flow at a stationary bottleneck is developed to determine the parameters that cause congestion. Towards this goal, traffic density, speed, and delay were acquired during peak and off-peak periods in the morning and afternoon at a stationary bottleneck in Peshawar, KPK, Pakistan. The morning and afternoon peak periods have high densities, low speeds, and considerable delays. Regression models are developed using this data. These results indicate that there is a linear relationship between density and time at the stationary bottleneck and a negative linear relationship between density and speed. Thus, an increase in density increases the time delay and reduces the speed. I comprehensive traffic delay model is characterized by a stationary bottleneck. The Kolmogorov-Smirnov (KS) test and P-values were used to identify the best-fit distribution for speed and density. The binomial and generalized extreme values are considered the best fits for density and speed. The results presented can be used to develop accurate simulation models for stationary bottlenecks to reduce congestion. Doi: 10.28991/CEJ-2022-08-11-02 Full Text: PD

    Some comments on spacelike minimal surfaces with null polygonal boundaries in AdSmAdS_m

    Full text link
    We discuss some geometrical issues related to spacelike minimal surfaces in AdSmAdS_m with null polygonal boundaries at conformal infinity. In particular for AdS4AdS_4, two holomorphic input functions for the Pohlmeyer reduced system are identified. This system contains two coupled differential equations for two functions α(z,zˉ)\alpha (z,\bar z) and β(z,zˉ)\beta (z,\bar z), related to curvature and torsion of the surface. Furthermore, we conjecture that, for a polynomial choice of the two holomorphic functions, the relative positions of their zeros encode the conformal invariant data of the boundary null 2n2n-gon.Comment: 13 pages, a note and references added, version to appear in JHE
    • …
    corecore