454 research outputs found

    Large probe arrays for measuring mean and time dependent local oil volume fraction and local oil velocity component distributions in inclined oil-in-water flows

    Get PDF
    Arrays of dual-sensor and four-sensor needle conductance probes have been used to measure the mean and time dependent local properties of upward inclined, bubbly oil-in-water flows (also known as dispersed oil-in-water flows) in a 153mm diameter pipe. The flow properties that were measured were (i) the local in-situ oil volume fraction ; (ii) the local oil velocity in the axial direction of the pipe (the direction); and (iii) the local oil velocity in the direction from the lower side of the inclined pipe to its upper side (the direction). Oil velocities in the direction (orthogonal to the and directions) were found to be negligible. For all of the flow conditions investigated it was found that the mean value of varied from a maximum value at the upper side of the inclined pipe to a minimum value at the lower side, and that the rate of decrease of this mean value of with distance in the direction became greater as the pipe inclination angle from the vertical was increased. It was also found that the mean value of was greatest at the upper side of the inclined pipe and decreased towards the lower side of the inclined pipe, the rate of decrease with distance in the direction again becoming greater as was increased. For , a water volumetric flow rate , an oil volumetric flow rate and using a sampling period over a total time interval of , it was found that at the upper side of the inclined pipe the standard deviation in was 31.6% of the mean value of . Furthermore for , , and it was found that the standard deviation in the cross-pipe oil velocity component was approximately equal to the standard deviation in the axial velocity component . These large temporal variations in the local flow properties have been attributed to the presence of large scale Kelvin-Helmholtz waves which intermittently appear in the flow. It is believed that the techniques outlined in this paper for measuring the standard deviation of local flow properties as a function of the sampling period will be of considerable value in validating mathematical models of time dependent oil-water flows. It should be noted that the principal focus of this paper is on the measurement techniques that were used and the methods of data analysis rather than the presentation of exhaustive experimental results at numerous different flow conditions

    Developments in Structuring of Reformed Theology:The Synopsis Purioris Theologiae (1625) as Example

    Get PDF
    The Synopsis Purioris Theologiae (1625), an influential handbook of Reformeddogmatics, began as a cycle of disputations. A comparison of it with the cyclesthat were held previously in Leiden reveals some shifts in the structure of Reformeddogmatics. After introducing the Synopsis, this paper highlights thefunction of prolegomena, the place of predestination, and the relationship betweenthe magistrate and eschatology. It concludes that the choices made in theSynopsis illustrate tensions in Reformed theology. After the conflict with theRemonstrants it became urgent to carefully define the character of theology inthe prolegomena, to relate predestination to the person and work of Christ, andto connect the task of the magistrate to the doctrine of the church

    Evidence for a mixed mass composition at the `ankle' in the cosmic-ray spectrum

    Get PDF
    We report a first measurement for ultra-high energy cosmic rays of the correlation between the depth of shower maximum and the signal in the water Cherenkov stations of air-showers registered simultaneously by the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlation measurement is a unique feature of a hybrid air-shower observatory with sensitivity to both the electromagnetic and muonic components. It allows an accurate determination of the spread of primary masses in the cosmic-ray flux. Up till now, constraints on the spread of primary masses have been dominated by systematic uncertainties. The present correlation measurement is not affected by systematics in the measurement of the depth of shower maximum or the signal in the water Cherenkov stations. The analysis relies on general characteristics of air showers and is thus robust also with respect to uncertainties in hadronic event generators. The observed correlation in the energy range around the `ankle' at lg‚Ā°(E/eV)=18.5‚ąí19.0\lg(E/{\rm eV})=18.5-19.0 differs significantly from expectations for pure primary cosmic-ray compositions. A light composition made up of proton and helium only is equally inconsistent with observations. The data are explained well by a mixed composition including nuclei with mass A>4A > 4. Scenarios such as the proton dip model, with almost pure compositions, are thus disfavoured as the sole explanation of the ultrahigh-energy cosmic-ray flux at Earth.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

    Get PDF
    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS