5,076 research outputs found

    Non-catalytic bromination of benzene: a combined computational and experimental study

    Get PDF
    The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable (The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable (The non-catalytic bromination of benzene is shown experimentally to require high 5-14M concentrations of bromine in order to proceed at ambient temperatures to form predominantly bromobenzene, along with detectable

    Angular distributions in J/ψppˉπ0(η)J/\psi\to p\bar{p}\pi^{0}(\eta) decays

    Get PDF
    The differential decay rates of the processes J/ψppˉπ0J/\psi\to p\bar{p}\pi^{0} and J/ψppˉηJ/\psi\to p\bar{p}\eta close to the ppˉp\bar{p} threshold are calculated with the help of the NNˉN\bar{N} optical potential. The same calculations are made for the decays of ψ(2S)\psi(2S). We use the potential which has been suggested to fit the cross sections of NNˉN\bar{N} scattering together with NNˉN\bar{N} and six pion production in e+ee^{+}e^{-} annihilation close to the ppˉp\bar{p} threshold. The ppˉp\bar{p} invariant mass spectra is in agreement with the available experimental data. The anisotropy of the angular distributions, which appears due to the tensor forces in the NNˉN\bar{N} interaction, is predicted close to the ppˉp\bar{p} threshold. This anisotropy is large enough to be investigated experimentally. Such measurements would allow one to check the accuracy of the model of NNˉN\bar{N} interaction.Comment: 10 pages, 8 figure

    Исследование работы стеклопластиковых крепежных элементов в стеновых конструкциях

    Full text link
    The article is devoted to the study of pull-out tests of fiberglass plastic dowels installed in the walls made of lightweight concrete. The authors have undertaken experimental tests of anchors in use on the construction site and conducted analysis of test results.Работа посвящена исследованию характеристик сцепления композитных стеклопластиковых дюбелей с легким бетоном. Авторами проведены экспериментальные испытания анкеров в натурных условияx на строительной площадке и выполнен анализ результатов испытаний

    Natural explanation of recent results on e+eΛΛˉe^{+}e^{-}\to\Lambda\bar{\Lambda}

    Full text link
    We show that the recent experimental data on the cross section of the process e+eΛΛˉe^{+}e^{-}\to\Lambda\bar{\Lambda} near the threshold can be perfectly explained by the final-state interaction of Λ\Lambda and Λˉ\bar{\Lambda}. The enhancement of the cross section is related to the existence of low-energy real or virtual state in the corresponding potential. We present a simple analytical formula that fits the experimental data very well.Comment: 2 pages, 1 figur

    Harmonic oscillators in the Nos\'e - Hoover thermostat

    Full text link
    We study the dynamics of an ensemble of non-interacting harmonic oscillators in a nonlinear dissipative environment described by the Nos\'e - Hoover model. Using numerical simulation we find the histogram for total energy, which agrees with the analysis of the Nos\'e - Hoover equations effected with the method of averaging. The histogram does not correspond to Gibbs' canonical distribution. We have found oscillations at frequency proportional to α/m\sqrt{\alpha/m}, α\alpha the dissipative parameter of thermostat and mm the characteristic mass of particle, about the stationary state corresponding to equilibrium. The oscillations could have an important bearing upon the analysis of simulating molecular dynamics in the Nos\'e - Hoover thermostat.Comment: 7 pages, 4 figure

    Energy loss for heavy quarks in relation to light partons; is radiative energy loss for heavy quarks anomalous?

    Full text link
    The scaling properties of jet suppression measurements are compared for non-photonic electrons (e±e^{\pm}) and neutral pions (π0\pi^0) in Au + Au collisions at sNN=200\sqrt{s_{NN}}=200 GeV. For a broad range of transverse momenta and collision centralities, the comparison is consistent with jet quenching dominated by radiative energy loss for both heavy and light partons. Less quenching is indicated for heavy quarks via e±e^{\pm}; this gives an independent estimate of the transport coefficient q^\hat{q} that agrees with its magnitude obtained from quenching of light partons via π0\pi^0's.Comment: Published versio

    Mining open datasets for transparency in taxi transport in metropolitan environments.

    Get PDF
    Uber has recently been introducing novel practices in urban taxi transport. Journey prices can change dynamically in almost real time and also vary geographically from one area to another in a city, a strategy known as surge pricing. In this paper, we explore the power of the new generation of open datasets towards understanding the impact of the new disruption technologies that emerge in the area of public transport. With our primary goal being a more transparent economic landscape for urban commuters, we provide a direct price comparison between Uber and the Yellow Cab company in New York. We discover that Uber, despite its lower standard pricing rates, effectively charges higher fares on average, especially during short in length, but frequent in occurrence, taxi journeys. Building on this insight, we develop a smartphone application, OpenStreetCab, that offers a personalized consultation to mobile users on which taxi provider is cheaper for their journey. Almost five months after its launch, the app has attracted more than three thousand users in a single city. Their journey queries have provided additional insights on the potential savings similar technologies can have for urban commuters, with a highlight being that on average, a user in New York saves 6 U.S. Dollars per taxi journey if they pick the cheapest taxi provider. We run extensive experiments to show how Uber's surge pricing is the driving factor of higher journey prices and therefore higher potential savings for our application's users. Finally, motivated by the observation that Uber's surge pricing is occurring more frequently that intuitively expected, we formulate a prediction task where the aim becomes to predict a geographic area's tendency to surge. Using exogenous to Uber data, in particular Yellow Cab and Foursquare data, we show how it is possible to estimate customer demand within an area, and by extension surge pricing, with high accuracy.This is the final version of the article. It was first available from Springer via http://dx.doi.org/10.1140/epjds/s13688-015-0060-
    corecore