92 research outputs found

    Feed Production and Livestock Feeding: Trends and Tendencies

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    This paper is one of a series reviewing various forms of traditional agricultural production and related aspects. Preliminary work on this review was carried out within the scope of activities of the Food and Agriculture Program's Task 2 ("Technological Transformations in Agriculture: Resource Limitations and Environmental Consequences"). One of the goals of this task's activities is the review of various alternative technologies available in the world for the production of major crops and animal products. This paper can be seen as a first step towards this final objective providing information backed by concrete data. Research work on the topics presented has been carried out partly at IIASA and partly at the All-Union Research Institute of Information and Technical-Economic Research in Agriculture

    Effect of deposition parameters on microstructure and tribological properties of hard CA-PVD multi-component TiAlCrN and TiAlCrCN coatings

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    Multicomponent TiAlCrN and TiAlCrCN coatings were deposited using vacuum arc evaporation technique on AISI 430 stainless steel. The influence of working gas pressure, C ⁄ N ratio, bias voltage on the structure and tribomechanical properties of the obtained coatings has been studied. The surface morphology, chemical compound of the coatings obtained under the various conditions has been analyzed by SEM with EDX, XRD, and XRF analysis. The dry wear pad-on-disc tests against 100Cr6 counterbody at 20 N load have been carried out. It was established that Vickers micro-hardness was varied from 26 to 41 GPa depending on deposition parameters.Багатокомпонентні покриття TiAlCrN і TiAlCrCN були нанесені методом вакуумно-дугового осадження на нержавіючу сталь AISI 430. Вивчено вплив тиску робочого газу, відношення C ⁄ N, напруги зсуву на структуру і трібологічні властивості отриманих покриттів. Морфологія поверхні, хімічний і фазовий склади покриттів були досліджені за допомогою SEM з EDX-, XRD- і XRF-аналізів. Були проведені трибологічні випробування покриттів в умовах сухого тертя за схемою «диск-колодка» з контртілом зі сталі 100Cr6 при навантаженні 20 Н. Встановлено, що мікротвердість покриттів варіюється від 26 до 41 ГПа в залежності від параметрів осадження.Многокомпонентные покрытия TiAlCrN и TiAlCrCN были нанесены методом вакуумно-дугового осаждения на нержавеющую сталь AISI 430. Изучены влияния давления рабочего газа, отношения C ⁄ N, напряжения смещения на структуру и трибологические свойства полученных покрытий. Морфология поверхности, химический и фазовый составы покрытий были исследованы с помощью SEM с EDX-, XRD- и XRF-анализов. Были проведены трибологические испытания покрытий в условиях сухого трения по схеме «диск-колодка» с контртелом из стали 100Cr6 при нагрузке 20 Н. Установлено, что микротвердость покрытий варьируется от 26 до 41 ГПа в зависимости от параметров осаждения

    Pure Gauge Configurations and Tachyon Solutions to String Field Theories Equations of Motion

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    In constructions of analytical solutions to open string field theories pure gauge configurations parameterized by wedge states play an essential role. These pure gauge configurations are constructed as perturbation expansions and to guaranty that these configurations are asymptotical solutions to equations of motions one needs to study convergence of the perturbation expansions. We demonstrate that for the large parameter of the perturbation expansion these pure gauge truncated configurations give divergent contributions to the equation of motion on the subspace of the wedge states. We perform this demonstration numerically for the pure gauge configurations related to tachyon solutions for the bosonic and the NS fermionic SFT. By the numerical calculations we also show that the perturbation expansions are cured by adding extra terms. These terms are nothing but the terms necessary to make valued the Sen conjectures.Comment: 30 pages, 9 figures, references added and conclusion extende

    Study of the lineshape of the chi(c1) (3872) state

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    A study of the lineshape of the chi(c1) (3872) state is made using a data sample corresponding to an integrated luminosity of 3 fb(-1) collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate chi(c1)(3872) and psi(2S) mesons from b-hadron decays are selected in the J/psi pi(+)pi(-) decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the chi(c1 )(3872) and psi(2S) states, Delta m, and the width of the chi(c1 )(3872) state, Gamma(Bw), are determined to be (Delta m=185.598 +/- 0.067 +/- 0.068 Mev,)(Gamma BW=1.39 +/- 0.24 +/- 0.10 Mev,) where the first uncertainty is statistical and the second systematic. Using a Flatte-inspired model, the mode and full width at half maximum of the lineshape are determined to be (mode=3871.69+0.00+0.05 MeV.)(FWHM=0.22-0.04+0.13+0.07+0.11-0.06-0.13 MeV, ) An investigation of the analytic structure of the Flatte amplitude reveals a pole structure, which is compatible with a quasibound D-0(D) over bar*(0) state but a quasivirtual state is still allowed at the level of 2 standard deviations

    Measurement of the CKM angle γγ in B±DK±B^\pm\to D K^\pm and B±Dπ±B^\pm \to D π^\pm decays with DKS0h+hD \to K_\mathrm S^0 h^+ h^-

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    A measurement of CPCP-violating observables is performed using the decays B±DK±B^\pm\to D K^\pm and B±Dπ±B^\pm\to D \pi^\pm, where the DD meson is reconstructed in one of the self-conjugate three-body final states KSπ+πK_{\mathrm S}\pi^+\pi^- and KSK+KK_{\mathrm S}K^+K^- (commonly denoted KSh+hK_{\mathrm S} h^+h^-). The decays are analysed in bins of the DD-decay phase space, leading to a measurement that is independent of the modelling of the DD-decay amplitude. The observables are interpreted in terms of the CKM angle γ\gamma. Using a data sample corresponding to an integrated luminosity of 9fb19\,\text{fb}^{-1} collected in proton-proton collisions at centre-of-mass energies of 77, 88, and 13TeV13\,\text{TeV} with the LHCb experiment, γ\gamma is measured to be (68.75.1+5.2)\left(68.7^{+5.2}_{-5.1}\right)^\circ. The hadronic parameters rBDKr_B^{DK}, rBDπr_B^{D\pi}, δBDK\delta_B^{DK}, and δBDπ\delta_B^{D\pi}, which are the ratios and strong-phase differences of the suppressed and favoured B±B^\pm decays, are also reported

    Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at √sNN = 5.02 TeV with the LHCb detector

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    Flow harmonic coefficients, v n , which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02 TeV . The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features

    Helium identification with LHCb

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    The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using pp collision data at √(s) = 13 TeV recorded by the LHCb experiment in the years 2016 to 2018, corresponding to an integrated luminosity of 5.5 fb-1. A total of around 105 helium and antihelium candidates are identified with negligible background contamination. The helium identification efficiency is estimated to be approximately 50% with a corresponding background rejection rate of up to O(10^12). These results demonstrate the feasibility of a rich programme of measurements of QCD and astrophysics interest involving light nuclei

    Curvature-bias corrections using a pseudomass method

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    Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy √(s)=13 TeV during 2016, 2017 and 2018. The biases are determined using Z→μ + μ - decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10-4 GeV-1 level, improves the Z→μ + μ - mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass

    Study of the doubly charmed tetraquark T+cc

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    Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed
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