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Detailed experimental investigations of the amplitude dependence of flame describing functions (FDF) were performed using a stratified swirl-stabilized combustor, in order to understand the combustion–acoustic interactions of CH4/air flames propagating into nonhomogeneous reactant stoichiometry. Phase-synchronized OH planar laser induced fluorescence (OH PLIF) measurements were used to investigate local reaction zone structures of forced flames. To determine the amplitude- and frequency-dependent forced flame response, simultaneous measurements of inlet velocity and heat release rate oscillations were made using a constant temperature anemometer and photomultiplier tubes with narrow-band OH*/CH* interference filters. The measurements were made over a wide range of stratification ratios, including inner stream enrichment (ϕ i > ϕ o ) and outer stream enrichment (ϕ o > ϕ i ) conditions, and compared to the baseline condition of spatially and temporally homogeneous cases (ϕ i = ϕ o ). Results show that fo...

SummaryScab, caused by Venturia nashicola, is one of the most damaging diseases in pear. The development of varieties resistant to scab has long been an aim of Asian pear breeding programmes. The application of molecular markers to select scab-resistant plants will increase the efficiency of breeding programmes. To identify DNA markers linked to the scab-resistance gene named Rvn2 in PS2-93-3-98, the progeny of a cross between PS2-93-3-98 and ‘Yali’ pear was studied. As scab-resistance clearly segregated 1:1 in the F1 progeny, Rvn2 is a single dominant gene. Bulked segregant analysis and amplified fragment length polymorphism (AFLP) analysis were then applied to identify markers associated with Rvn2. Three AFLP markers linked to Rvn2 were identified. Mapping of the markers indicated that the three selected markers, E-AGT/M-CCA234, E-ATT/M-CCG328, and E-GGT/M-TCT217, were located 4.9, 3.2, and 0.8 cM from the Rvn2 locus, respectively. Rvn2 was found to be located in a different linkage group from previousl...

Paraelectric lead lanthanium titanate (PLT) thin films were deposited Pt/Ti/SiO2/Si multilayer substrates by a multi element metal target using dc magnetron sputtering. The rate of each metal component area on multi element target was obtained by the modified Sigmund's method, suggesting sputtering yields for Pb, La, and Ti metals. A post annealing treatment was applied to all PLT thin films at the temperature ranges from 450°C to 750°C for crystallization into the cubic perovskite structure. The crystallization of PLT thin films was characterized by X-ray diffraction, and their compositions were analyzed by Auger electron spectroscopy. The temperature dependence of dielectric constant in PLT film at La content of 22 mol% had the broad peak at around 60°C, however, and the dielectric constant at La content of 28 mol% decreased slightly at the temperature range of 30∼ 120°C. The dielectric constant of the PLT films increased with La contents. The dielectric constant and loss tangent at the La concentration...

The stage 1 compaction behaviour of tool steel powder under die pressing was studied. The effects of friction between the powder and the die wall were also investigated under different die pressing modes. The e1astop1asticconstitutive equations based on the yield functions by Fleck et al. and by Shima and Oyane were implemented in a finite element programme to simulate die compaction processes. Finite element calculations were compared with experimental data for densification and density distributions of tool steel powder under single and double action die pressing. Finite element calculations using the yield function by Fleck et al. agreed better with experimental data than those by Shima and Oyane. PM/0775

The thermoviscoplastic response and the densification behaviour of porous alloy steel preforms under hot upsetting conditions are investigated at various temperatures and strain rates. A higher den...

A new series of detailed observations of the Coma cluster of galaxies has been undertaken with the aim of better specifying the intergalactic gas component through high dynamic range, combined-telescope observations of the radio emission from the cluster which detect both the cluster-scale and galaxy-scale emission. By combining these multi-frequency radio maps with a Faraday rotation probe experiment using cluster and background sources, and the published X-ray data, we have been able to estimate the intracluster magnetic field strength independently of the usual assumptions of equipartition. The result is approximately 2 microgauss. We compare the X-ray and radio distributions in detail, and describe how our combined results suggest that acceleration of the relativistic electrons occurs in situ, and we suggest that the conditions in the cluster provide good physical arguments to support this.

A mathematical model is proposed to describe the variation with time of pressure, relative density, and temperature for metal powders during hot compaction. The model includes instantaneous response, equilibrium response, and creep response and is based on a micromechanical (hollow sphere) analysis. However, the development is mostly empirical, based on experimental data from hot compaction of iron powder. The instantaneous and equilibrium responses are described by linear response laws, whereas time dependent densification is described by a power law creep response. The experimental data support these assumptions. Agreement between theoretical curves and experimental data is very good. PM/0500

The densification behaviour of iron and copper powders during die compaction has been simulated with several plastic models and the results compared with actual experimental data. The experimental data of Brown were used to obtain the empirical constants of the Cam–clay model. The Cam–clay model simulates actual behaviour during die compaction significantly better than do the Shima and Fleck models. PM/0750

The effect of a radial steady-state temperature gradient on elastic-plastic expansion of a hollow sphere or a spherical cavity in an infinite medium is investigated for homogeneous, isotropic, incompressible, temperature-dependent elastic-plastic strain hardening material. By employing appropriate temperature-dependent elastic and plastic strain hardening laws based on experimental data, the solutions for spherical inflation problems can be obtained in terms of elementary functions