5,340 research outputs found

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

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    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

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    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

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    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

    Harmonic oscillators in the Nos\'e - Hoover thermostat

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    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

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

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    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-

    Evidence of phi --> pi0 pi0 gamma and phi --> pi0 eta gamma decays in SND experiment at VEPP-2M

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    Preliminary results on the study of e+e- --> phi(1020) --> pi0 pi0 gamma, eta pi0 gamma processes from SND experiment at VEPP-2M collider in Novosibirsk are presented. Branching ratios of rare radiative phi --> pi0 pi0 gamma and phi --> pi0 eta gamma decays are measured: B(phi --> pi0 pi0 gamma ) = (1.1 +- 0.2) * 10^-4 (invariant mass (pi0 pi0) < 800 MeV), B(phi --> eta pi0 gamma ) = (1.3 +- 0.5) * 10^-4.Comment: Talk at the HADRON97 conference, BNL, Aug 24-30 1997; LaTeX, 4 pages, 4 eps figure
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