CF6 performance improvement

Potential CF6 engine performance improvements directed at reduced fuel consumption were identified and screened relative to airline acceptability and are reviewed. The screening process developed to provide evaluations of fuel savings and economic factors including return on investment and direct operating cost is described. In addition, assessments of development risk and production potential are made. Several promising concepts selected for full-scale development based on a ranking involving these factors are discussed

'Like-With-Like’: A Comparison of Natural and Synthetic Stitching Threads used in Textile Conservation

This paper reports research undertaken to investigate thread types used in textile conservation by quantitatively evaluating tensile strength and damage to conserved samples. A literature review and questionnaire sent to textile conservators were used to establish the most commonly used threads for laid-thread couching treatments and the rationale behind thread choice. Most common threads found were two-ply hair silk and polyester Tetex as well as other fine polyester, silk and cotton varieties. Three natural fibre plain-weave artefact samples conserved by laid-thread couching with five different thread types (lace cotton, hair silk, organsin, Skala and Tetex) were subjected to either tensile strength testing or a fixed-load experiment for two weeks. The tensile strength tests determined that the conservation treatment provided effective support and different thread types did not give statistically different results. The fixed-load experiment determined that longer time periods created more damage, even with lighter loads

Mechanical properties of wool and cotton yarns used in twenty-first century tapestry: preparing for the future by understanding the present

The conservation of historic tapestries is a complex and highly skilled task. Tapestries now being woven will need conservation in years to come. Can we, by understanding the properties of these contemporary works, assist the conservators of the future? The recreation of the Hunt of the Unicorn tapestries being undertaken by the West Dean Tapestry Studio offers a unique opportunity to access the materials being used and to create a body of data on their initial properties. This study uses tensile testing of the warp and weft materials to determine their maximum load at break, extension at maximum load, and specific stress (tenacity). Wool weft yarns from two different sources and of two thicknesses were examined. These wools were dyed ‘in house’ and the effect of the different dyes used was also assessed. These parameters all showed some significant (P < 0.05) differences. Cotton warp yarns of differing thickness and a gold thread were also tested. The comparison of how cotton and wool break demonstrates that when a tapestry is put under sufficient stress the cotton will snap but the wool may only stretch. However, this could often be beyond its recovery range resulting in a failure to return to shape

Development of non-destructive methodology using ATR-FTIR with PCA to differentiate between historical Pacific barkcloth

Barkcloths, non-woven textiles originating from the Pacific Islands, form part of many museum collections and date back to the 18th and 19th centuries. The ability to determine different plant species which have been used for producing barkcloth is required by art historians to help understand the origin and use of the cloths and by conservators for whom the species type may have an impact on textile durability, deterioration and hence conservation. However, to date the development of a non-destructive, robust analytical technique has been elusive. This article describes the use of Fourier transform infrared spectroscopy with attenuated total reflection (ATR-FTIR) and principal component analysis (PCA) todifferentiation between historic barkcloths. Three distinct groups of historic cloths were identified using PCA of the FTIR region between 1200 and 1600 cm−1 where molecular vibrations associated with tannins and lignins are dominant. Analysis of contemporary cloths only identified Pipturus albidus cloth as different and highlighted the difficulties around producing a representative textile sample to mimic the historic cloths. While the methodology does not itself identify species, the use of historically well-provenanced samples allows cloths showing similarities to group together and is a significant aid to identification

Enabling Texts

Produced by Hawai'i University Affiliated Program on Disabilities, University of Hawai'i at Manoa, Honolulu, Hawai'i, Frank Sawyer School of Management, Suffolk University, Boston, Massachusetts, and School of Social Sciences, The University of Texas at Dallas, Richardson, Texas for The Society for Disability Studies

Book Review

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An Analysis of the Quasicontinuum Method

The aim of this paper is to present a streamlined and fully three-dimensional version of the quasicontinuum (QC) theory of Tadmor et al. and to analyze its accuracy and convergence characteristics. Specifically, we assess the effect of the summation rules on accuracy; we determine the rate of convergence of the method in the presence of strong singularities, such as point loads; and we assess the effect of the refinement tolerance, which controls the rate at which new nodes are inserted in the model, on the development of dislocation microstructures.Comment: 30 pages, 16 figures. To appear in Jornal of the Mechanics and Physics of Solid

Capturing coordination and intentionality in joint musical improvisation.

Humans collaborate with each other on a wide variety of tasks that are often largely improvised and unscripted. In this study, we investigated the dynamics of coordination in a joint musical improvisation task, what the effect of intentions is on coordination, and how musicians propagate these intentions. To quantify coordination within musical trios, we derived per-musician time series of acoustic features to which we applied effective transfer entropy (ETE) and empirical dynamic modeling (EDM), two methods derived from complex systems science. Using ETE allowed us to investigate coordination as directional information flow between musicians, whereas through EDM we conceptualized coordination as the predictability of a complex system. We found that both techniques, when applied to root-mean-square (RMS) amplitude time series, could be used to distinguish coordinating from noncoordinating musicians. Various other feature-technique combinations, such as fractal dimension-ETE and Tonnetz distance-EDM, were also viable. Our results further suggest that coordination improves as an intention gets more shared, that is, as more musicians in the joint improvisation have the same intention. Lastly, we found evidence suggesting that musicians increase the predictability of their playing when seeking to end a performance, though our results did not provide an indication that this was done with the intention of improving coordination with partners

Surface-directed spinodal decomposition in the pseudobinary alloy (HfO_2)_x(SiO_2)_{1-x}

Hf silicate films (HfO_2)_{0.25}(SiO_2)_{0.75} with thicknesses in the range 4-20 nm were grown on silicon substrate by atomic layer deposition at 350 deg.C.The Hf distributions in as-grown and 800 deg.C annealed films were investigated by high resolution transmission electron microscopy (HRTEM), angle-resolved x-ray photoelectron spectroscopy (ARXPS) and medium energy ion scattering (MEIS). HRTEM images show a layered structure in films thinner than 8 nm. The ARXPS data also reveal a non-uniform distribution of Hf throughout the film depth. Diffusion of SiO_2 to the film surface after a longer time anneal was observed by MEIS. All these observations provide evidence for surface-directed spinodal decomposition in the pseudobinary (HfO_2)_x(SiO_2)_{1-x} alloy system.Comment: 1o figures, one tabl