Conceptual design study of advanced acoustic composite nacelle

Conceptual nacelle designs for wide-bodied and for advanced-technology transports were studied with the objective of achieving significant reductions in community noise with minimum penalties in airplane weight, cost, and in operating expense by the application of advanced composite materials to nacelle structure and sound suppression elements. Nacelle concepts using advanced liners, annular splitters, radial splitters, translating centerbody inlets, and mixed-flow nozzles were evaluated and a preferred concept selected. A preliminary design study of the selected concept, a mixed flow nacelle with extended inlet and no splitters, was conducted and the effects on noise, direct operating cost, and return on investment determined

On the dynamic tensile strength of Zirconium

Despite its fundamental nature, the process of dynamic tensile failure (spall) is poorly understood. Spall initiation via cracks, voids, etc, before subsequent coalesce, is known to be highly microstructure-dependant. In particular, the availability of slip planes and other methods of plastic deformation controls the onset (or lack thereof) of spall. While studies have been undertaken into the spall response of BCC and FCC materials, less attention has paid to the spall response of highly anisotropic HCP materials. Here the dynamic behaviour of zirconium is investigated via plate-impact experiments, with the aim of building on an ongoing in-house body of work investigating these highly complex materials. In particular, in this paper the effect of impact stress on spall in a commercially sourced Zr rod is considered, with apparent strain-rate softening highlighted

Connecting Localism and Community Empowerment: Research Review and Critical Synthesis for the AHRC Connected Community Programme

The Connecting Localism and Community Empowerment project sought to assess the merits of the assumption that localisms brings about community empowerment through a review of the existing academic and policy literatures. The key findings from the review point towards a lack of clarity and coherence in the literature in the usage and interpretations of the terms ‗localism‘ and ‗community empowerment‘. They are often defined by implication or tacitly assumed to have an accepted definition. Whilst greater localism is generally claimed to increase community empowerment, there are substantive grounds for questioning this claim, which arise from critically analysing these concepts and how they interact. These grounds highlight conditions which need to be fulfilled if localism is to realise its potential to enhance community empowerment. To understand these conditions we analysed four international case studies. We also consider two assessments of the New Labour government‘s localist policies in the UK

Farnham rolls investigation

The object of this experiment was to investigate the possibility of obtaining pre-setting data for the 1 Farnham Rolls'. The experiment was carried out by applying certain deflections and measuring the resulting radii of curvature. Thus curves of curvature against deflection were produced for different sheet widths, and from these curves attempts to produce a conical frustum with prescribed radii were made. The results obtained can not be applied to conical parts, but this test served to indicate that it is possible to obtain pre-setting data for various applications

Mutator Dynamics on a Smooth Evolutionary Landscape

We investigate a model of evolutionary dynamics on a smooth landscape which features a ``mutator'' allele whose effect is to increase the mutation rate. We show that the expected proportion of mutators far from equilibrium, when the fitness is steadily increasing in time, is governed solely by the transition rates into and out of the mutator state. This results is a much faster rate of fitness increase than would be the case without the mutator allele. Near the fitness equilibrium, however, the mutators are severely suppressed, due to the detrimental effects of a large mutation rate near the fitness maximum. We discuss the results of a recent experiment on natural selection of E. coli in the light of our model.Comment: 4 pages, 3 figure

Estimating oceanic primary production using vertical irradiance and chlorophyll profiles from ocean gliders in the North Atlantic

An autonomous underwater vehicle (Seaglider) has been used to estimate marine primary production (PP) using a combination of irradiance and fluorescence vertical profiles. This method provides estimates for depth-resolved and temporally evolving PP on fine spatial scales in the absence of ship-based calibrations. We describe techniques to correct for known issues associated with long autonomous deployments such as sensor calibration drift and fluorescence quenching. Comparisons were made between the Seaglider, stable isotope (13C), and satellite estimates of PP. The Seaglider-based PP estimates were comparable to both satellite estimates and stable isotope measurements

Search for Point Sources of Ultra-High Energy Cosmic Rays Above 40 EeV Using a Maximum Likelihood Ratio Test

We present the results of a search for cosmic ray point sources at energies above 40 EeV in the combined data sets recorded by the AGASA and HiRes stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. No statistically significant clustering of events consistent with a point source is found.Comment: 7 pages, 7 figures. Accepted for publication in The Astrophysical Journa