7,515 research outputs found

    A test of spray nozzles

    Get PDF
    Cover title.Also continuously numbered from previous Bulletin (p. 88-115) on upper outside corner.The height of spray -- Shape and density of spray -- Size of drops -- Amount of discharge -- Clogging -- Dribbling -- Durability -- Method of attachment

    A review of the epidemiology, diagnosis, treatment, vaccines and economic impact of human monkeypox (Mpox) outbreaks

    Get PDF
    The current monkeypox outbreak is a public health emergency of international concern and is coming in the wake of the SARS-CoV-2 pandemic. Human monkeypox is a viral zoonotic infection caused by monkeypox virus, an enveloped double-stranded DNA virus of the genus Orthopoxvirus and family Poxviridae that also contain smallpox, cowpox, Orf, and vaccinia viruses. Online databases including PubMed, Google Scholar and Web of Science were searched to obtain relevant publications on the epidemiology, treatment, vaccines and the economic impacts of the current monkeypox (Mpox) outbreak

    Application of Waste Glass Powder as a Partial Cement Substitute towards more Sustainable Concrete Production

    Get PDF
    Use of waste materials in concrete is now a global trend for efficient waste management so as to achieve a sustainable green environment and with the added advantages of preserving the natural resources as well as producing a better performing concrete. This study examined the properties of concrete containing ground waste glass powder (GP) as partial replacement for cement. The waste glass was finely grounded into powder and the morphology imagery of the powder materials was carried out using scanning electron microscopy (SEM). Moreover, the chemical composition of the glass powdered material was determined using X-ray fluorescence (XRF). Laboratory tests were carried out to determine the strength activity index, workability, split tensile and compressive strength properties of the concrete with 0%, 15%, 18%, 21%, 24%, 27% and 30% partial replacement of cement with the ground waste glass powder. The results showed that the oxides composition of the glass powder meets the requirements for pozzolanic material, while the SEM morphology shows materials of amorphous flaky solid masses, and based on the 28-day strength activity index, concrete containing 21% cement replacement shows a higher strength index above the recommended 75%. It was also observed that workability of the concrete reduced with increase in percentage glass content while significant improvement of the compressive strength of the concrete was achieved at 21% cement replacement, after which a decrease in strength with increasing percentage glass content was observed. The revealed results were confirmed by the microstructural examination using SEM showing a denser concrete at 21% cement replacement but increase porosity as the glass content increases. However, a decrease in split tensile strength was observed with increasing glass content. The results clearly showed that it is possible to produce moderate strength sustainable concrete for structural application using 20% glass powder as cement replacement

    Spatial string tension in Nf=2N_f=2 lattice QCD at finite temperature

    Full text link
    The spatial string tension across a crossover from the low temperature phase to the high temperature phase is computed in QCD with two flavors of non-perturbatively improved Wilson fermions at small lattice spacing a \sim 0.12fm. We find that in the low temperature phase spatial string tension agrees well with zero temperature string tension. Furthermore, it does not show increasing for temperatures up to T = 1.36 T_{pc}, the highest temperature considered. Our results agree with some theoretical predictions.Comment: 8 pages, 2 figures, numerical results and both figures slightly changed, comparison with theoretical predictions added, values of the ratio T/T_{pc} slightly change

    Isgur - Wise Functions for Confined Light Quarks in a Colour Electric Potential

    Full text link
    We explore the influence on the Isgur-Wise function of the colour electric potential between heavy and light quarks in mesons. It is shown that in bag models, its inclusion tends to restore light quark flavour symmetry relative to the MIT bag predictions, and that relative to this model it flattens the Isgur-Wise function. Results compare very well with observations.Comment: 9 pages, 1 figure (available upon request), Latex, TPJU - 4/9

    Slow crossover in YbXCu4 intermediate valence compounds

    Full text link
    We compare the results of measurements of the magnetic susceptibility Chi(T), the linear coefficient of specific heat Gamma(T)=C(T)/T and 4f occupation number nf(T) for the intermediate valence compounds YbXCu4 (X = Ag, Cd, In, Mg, Tl, Zn) to the predictions of the Anderson impurity model, calculated in the non-crossing approximation (NCA). The crossover from the low temperature Fermi liquid state to the high temperature local moment state is substantially slower in the compounds than predicted by the NCA; this corresponds to the ''protracted screening'' recently predicted for the Anderson Lattice. We present results for the dynamic susceptibility, measured through neutron scattering experiments, to show that the deviations between theory and experiment are not due to crystal field effects, and we present x-ray-absorption fine-structure (XAFS) results that show the local crystal structure around the X atoms is well ordered, so that the deviations probably do not arise from Kondo Disorder. The deviations may correlate with the background conduction electron density, as predicted for protracted screening.Comment: Submitted to Physical Review B on June 7, 2000, accepted for publication November 2, 2000. Changes to the original manuscript include: 1) a discussion of the relation of the slow crossover to the conduction electron density; 2) a discussion of the relation of the reported results to earlier photoemission results; and, 3) minor editorial change

    Survey of charge symmetry breaking operators for dd -> alpha pi0

    Full text link
    The charge-symmetry-breaking amplitudes for the recently observed d d -> alpha pi0 reaction are investigated. Chiral perturbation theory is used to classify and identify the leading-order terms. Specific forms of the related one- and two-body tree level diagrams are derived. As a first step toward a full calculation, a few tree-level two-body diagrams are evaluated at each considered order, using a simplified set of d and alpha wave functions and a plane-wave approximation for the initial dd state. The leading-order pion-exchange term is shown to be suppressed in this model because of poor overlap of the initial and final states. The higher-order one-body and short-range (heavy-meson-exchange) amplitudes provide better matching between the initial and final states and therefore contribute significantly and coherently to the cross section. The consequences this might have for a full calculation, with realistic wave functions and a more complete set of amplitudes, are discussed.Comment: REVTeX 4, 35 pages, 8 eps figures, submitted to PR

    Heavy Quark Free Energies and Screening in SU(2) Gauge Theory

    Full text link
    We investigate the singlet, triplet and colour average heavy quark free energies in SU(2) pure gauge theory at various temperatures T. We focus on the long distance behaviour of the free energies, studying in particular the temperature dependence of the string tension and the screening masses. The results are qualitatively similar to the SU(3) scenario, except near the critical temperature Tc of the deconfining transition. Finally we test a recently proposed method to renormalize the Polyakov loop.Comment: 5 pages, 4 figures, contribution to the Proceedings of SEWM 2002 (Heidelberg
    • …
    corecore