Influence of jet exit conditions on the passive scaler field of an axisymmetric free jet

The influence of initial flow conditions on the passive scalar field of a turbulent free jet issuing from the round nozzle is investigated in this paper by a review of the literature and a detailed experimental study. Two sets of distinctly different initial conditions are generated using two nozzle types: a smooth contraction and a long straight pipe. The present measurements of the passive scalar (temperature) field were conducted in a slightly heated air jet from each nozzle at a Reynolds number of 16 000 using identical experimental facilities and a single measurement technique. Significant differences between the flows from the two nozzles are revealed throughout the measured flow region which covers the axial range from 0 to 70 jet exit diameters. The study suggests that the differences observed in the statistics of the scalar field may be related to differences in the underlying turbulence structure of the jet in the near field. The present findings support the analytical result of George (1989) that the entire flow is influenced by the initial conditions, resulting in a variety of self-similar states in the far field.J. Mi, D. S. Nobes and G. J. Natha

The B Meson Decay Constant from Unquenched Lattice QCD

We present determinations of the B meson decay constant f_B and of the ratio f_{B_s}/f_B using the MILC collaboration unquenched gauge configurations which include three flavors of light sea quarks. The mass of one of the sea quarks is kept around the strange quark mass, and we explore a range in masses for the two lighter sea quarks down to m_s/8. The heavy b quark is simulated using Nonrelativistic QCD, and both the valence and sea light quarks are represented by the highly improved (AsqTad) staggered quark action. The good chiral properties of the latter action allow for a much smoother chiral extrapolation to physical up and down quarks than has been possible in the past. We find f_B = 216(9)(19)(4) (6) MeV and f_{B_s} /f_B = 1.20(3)(1).Comment: 4 pages, 2 figure

High-resolution geophysical surveying at the Springfield Fault, New Zealand

To trace the active Springfield Fault (South Island, New Zealand) and map its character at shallow depths on a terrace where it exhibits no surface expression, we recorded 3-D georadar data across an approximately rectangular 110 x 40 m survey area. In addition, we carried out multi-electrode geoelectric measurements along a 198 m long profile that crossed the georadar survey area. Although the georadar depth penetration was limited to only ~5 m, the processed images revealed the presence of a prominent reflecting horizon disrupted by three main discontinuities. Semi-continuous subhorizontal reflection patterns were interpreted to represent sedimentary units within the fluvial deposits, whereas three detected discontinuities were interpreted as fault traces with small near-vertical offsets (~0.4 m). This interpretation was supported by vertical and lateral changes visible on the final inverted resistivity model indicating lithological boundaries and fault branches

Topographic Evolution in the Atomic Scale Growth and Erosion Continuum

This review gives a detailed survey of the range of fascinating surface features which develop under growth or erosion conditions under the combined influence of thermal and more energetic atomic particle fluxes. Collisionally induced atomic ejection and migration, and thermally and radiation induced atom and defect diffusion processes are outlined and their relevance to topographic initiation and evolution explored. A range of experimental observations of surface feature elaboration is discussed from net growth to net erosion conditions and models for their explanation are considered. It is concluded that while much data have been accumulated, much of these have been in so diverse experimental conditions that precise modelling in atomic terms is difficult and generalisations are treacherous. A clear need for structured, extensive studies exists with very precise parameter definition and control

Recent results from lattice calculations

Recent results from lattice QCD calculations relevant to particle physics phenomenology are reviewed. They include the calculations of strong coupling constant, quark masses, kaon matrix elements, and D and B meson matrix elements. Special emphasis is on the recent progress in the simulations including dynamical quarks.Comment: 13 pages, 8 figures, plenary talk at the 32nd International Conference on High-Energy Physics (ICHEP 2004), August 16-22, 2004, Beijing, Chin

Design and Fabrication of a 1 m Model of the 70 mm Bore Twin Aperture Superconducting Quadrupole for the LHC Insertions

For reasons of geometrical acceptance, 70 mm bore twin aperture quadrupoles are required in the LHC insertions. For an operating gradient of 160 T/m at 4.5 K, a design based on a four layer coil wound from two graded 8.2 mm NbTi conductors has been developed. Three 1 m single aperture quadrupoles of this design have been built and successfully tested. Thereafter, the magnets have been disassembled and the coils re-collared using self-supporting collars. In this paper, we describe the design features of the twin aperture quadrupole, and report on the initial collaring tests and procedures for collaring and final assembly of the 1 m magnet

Leptonic decay constants f_Ds and f_D in three flavor lattice QCD

We determine the leptonic decay constants in three flavor unquenched lattice QCD. We use O(a^2)-improved staggered light quarks and O(a)-improved charm quarks in the Fermilab heavy quark formalism. Our preliminary results, based upon an analysis at a single lattice spacing, are f_Ds = 263(+5-9)(+/-24) MeV and f_D = 225(+11-13)(+/-21) MeV. In each case, the first reported error is statistical while the is the combined systematic uncertainty.Comment: Talk presented at Lattice2004(heavy), Fermilab, June 21-26, 2004. 3 pages, 2 figure

The influence of intention, outcome and question-wording on children's and adults' moral judgments

The influence of intention and outcome information on moral judgments was investigated by telling children aged 4-8 years and adults (N=169) stories involving accidental harms (positive intention, negative outcome) or attempted harms (negative intention, positive outcome) from two studies (Helwig, Zelazo, & Wilson, 2001; Zelazo, Helwig, & Lau, 1996). When the original acceptability (wrongness) question was asked, the original findings were closely replicated: children’s and adults’ acceptability judgments, and children’s punishment judgments, were primarily outcome-based. However, when this question was rephrased, 4-5-year-olds’ judgments were approximately equally influenced by intention and outcome, and from 5-6 years they were primarily intention-based. These findings indicate that, for methodological reasons, children’s (and adults’) ability to make intention-based judgment has often been substantially underestimated

Branching ratios of Bc Meson Decaying to Pseudoscalar and Axial-Vector Mesons

We study Cabibbo-Kobayashi-Maskawa (CKM) favored weak decays of Bc mesons in the Isgur-Scora-Grinstein-Wise (ISGW) quark model. We present a detailed analysis of the Bc meson decaying to a pseudoscalar meson (P) and an axial-vector meson (A). We also give the form factors involving transition in the ISGW II framework and consequently, predict the branching ratios of decays.Comment: 19 pages,7 table