5,993 research outputs found
Panel on future challenges in modeling methodology
This panel paper presents the views of six researchers and practitioners of simulation modeling. Collectively we attempt to address a range of key future challenges to modeling methodology. It is hoped that the views of this paper, and the presentations made by the panelists at the 2004 Winter Simulation Conference will raise awareness and stimulate further discussion on the future of modeling methodology in areas such as modeling problems in business applications, human factors and geographically dispersed networks; rapid model development and maintenance; legacy modeling approaches; markup languages; virtual interactive process design and simulation; standards; and Grid computing
Perceived impacts and residents\u27 support for tourism development in Port Dickson, Malaysia
This study evaluates the image that residents perceive of their location and its influences on their understanding of tourism impacts, and their support for the development of the tourism. The data was collected from 422 residents of Port Dickson in Malaysia and were examined by applying PLS-SEM. Results displayed a positive image of place will lead to positive perceptions of tourism development impacts leadings to residents\u27 support for tourism development. Practical implications of these outcomes are also discussed relative to tourism planning and development
Energy and environmental assessment and reuse of fluidised bed recycled carbon fibres
Carbon fibre reinforced plastic (CFRP) recycling and the reutilisation of the recovered carbon fibre (rCF) 2 can compensate for the high impacts of virgin carbon fibre (vCF) production. In this paper, we evaluate the 3 energy and environmental impacts of CF recycling by a fluidised bed process and reuse to manufacture a 4 CFRP material. A ‘gate-to gate’ life cycle model of the CFRP recycling route using papermaking and 5 compression moulding methods is developed based on energy analysis of the fluidised bed recycling process 6 and processing of rCF. Key recycling plant operating parameters, including plant capacity, feed rate, and air 7 2 in-leakage are investigated. Life cycle impact assessments demonstrate the environmental benefits of recycled 8 CFRP against end of life treatments-landfilling, incineration. The use of rCF to displace vCF based on 9 material indices (equivalent stiffness and equivalent strength) therefore proves to be a competitive alternative 10 for composite manufacture in terms of environmental impact
Automatic generation of 3D unstructured high-order curvilinear meshes
This is the final version of the article. Available from the publisher via the DOI in this record.The generation of suitable, good quality high-order meshes is a significant obstacle
in the academic and industrial uptake of high-order CFD methods. These methods have a number
of favourable characteristics such as low dispersion and dissipation and higher levels of
numerical accuracy than their low-order counterparts, however the methods are highly susceptible
to inaccuracies caused by low quality meshes. These meshes require significant curvature
to accuratly describe the geometric surfaces, which presents a number of difficult challenges in
their generation. As yet, research into the field has produced a number of interesting technologies
that go some way towards achieving this goal, but are yet to provide a complete system that
can systematically produce curved high-order meshes for arbitrary geometries for CFD analysis.
This paper presents our efforts in that direction and introduces an open-source high-order
mesh generator, NekMesh, which has been created to bring high-order meshing technologies
into one coherent pipeline which aims to produce 3D high-order curvilinear meshes from CAD
geometries in a robust and systematic way
Variation at the capsule locus, cps, of mistyped and non-typable Streptococcus pneumoniae isolates
The capsule polysaccharide locus (cps) is the site of the capsule biosynthesis gene cluster in encapsulated Streptococcus pneumoniae. A set of pneumococcal samples and non-pneumococcal streptococci from Denmark, the Gambia, the Netherlands, Thailand, the UK and the USA were sequenced at the cps locus to elucidate serologically mistyped or non-typable isolates. We identified a novel serotype 33B/33C mosaic capsule cluster and previously unseen serotype 22F capsule genes, disrupted and deleted cps clusters, the presence of aliB and nspA genes that are unrelated to capsule production, and similar genes in the non-pneumococcal samples. These data provide greater understanding of diversity at a locus which is crucial to the antigenic diversity of the pathogen and current vaccine strategies
New constraints from Central Chile on the origins of enriched continental compositions in thick-crusted arc magmas
Magmas from continental arcs built on thick crust have elevated incompatible element abundances and “enriched” radiogenic isotope ratios compared to magmas erupted in island and continental arcs overlying thinner crust. The relative influence of the slab, mantle, and upper plate on this variability is heavily debated. The Andean Southern Volcanic Zone (SVZ; 33-46° S) is an ideal setting to investigate the production of enriched continental arc compositions, because both crustal thickness and magma chemistry vary coherently along strike. However, the scarcity of primitive magmas in the thick-crusted northern SVZ has hindered
previous regional studies. To better address the origin of enriched continental compositions, we investigate the geochemistry (major and trace element abundances, 87Sr/86Sr and 143Nd/144Nd ratios) of new mafic samples from Don Casimiro and Maipo volcanoes in Diamante-Maipo Caldera Complex of the northern SVZ. While evolved Diamante-Maipo samples show evidence for crustal assimilation, the trace element and
isotopic enrichment of the most mafic samples cannot result from crustal processing, as no known regional or global basement lithologies are enriched in all of the necessary incompatible trace elements. Subduction
erosion models similarly fail to account for the enriched isotopic and trace element signature of these samples. Instead, we suggest that the enrichment of northern SVZ magmas is derived from an enriched ambient mantle component (similar to EM1-type ocean island basalts), superimposed on a northward decline in melt extent. A substantial, but nearly uniform contribution of melts from subducting sediment and altered oceanic crust are required at all latitudes. The EM1-like enrichment may arise from recycling of metasomatized subcontinental lithospheric mantle (M-SCLM), as the isotopic trajectory of primitive rear-arc monogenetic cones trend towards the compositions of SCLM melts sampled across South America. Isotopic data from spatially distributed rear-arc centres demonstrate that the arc-parallel variations in the degree of EM1-type enrichment observed in arc-front samples are also present up to 600 km behind the trench in the rear-arc. Rear-arc trace element systematics require significant but variable quantities of slab melts to be
transported to the mantle wedge at these large trench distances. Overall, we show that a unified model incorporating variable mantle enrichment, slab additions, and melt extents can account for along and acrossarc
trends within the SVZ. The recognition that mantle enrichment plays a key role in the production of enriched continental compositions in the SVZ has important implications for our understanding of the chemical evolution of the Earth. If ambient mantle enrichment is not taken into account, petrogenetic models of evolved lavas may overestimate the role of crustal assimilation, which, in turn, may lead models of
continental crust growth to overestimate the amount of continental material that has been recycled back into the mantle
Forefoot pathology in rheumatoid arthritis identified with ultrasound may not localise to areas of highest pressure: cohort observations at baseline and twelve months
BackgroundPlantar pressures are commonly used as clinical measures, especially to determine optimum foot orthotic design. In rheumatoid arthritis (RA) high plantar foot pressures have been linked to metatarsophalangeal (MTP) joint radiological erosion scores. However, the sensitivity of foot pressure measurement to soft tissue pathology within the foot is unknown. The aim of this study was to observe plantar foot pressures and forefoot soft tissue pathology in patients who have RA.Methods A total of 114 patients with established RA (1987 ACR criteria) and 50 healthy volunteers were assessed at baseline. All RA participants returned for reassessment at twelve months. Interface foot-shoe plantar pressures were recorded using an F-Scan® system. The presence of forefoot soft tissue pathology was assessed using a DIASUS musculoskeletal ultrasound (US) system. Chi-square analyses and independent t-tests were used to determine statistical differences between baseline and twelve months. Pearson’s correlation coefficient was used to determine interrelationships between soft tissue pathology and foot pressures.ResultsAt baseline, RA patients had a significantly higher peak foot pressures compared to healthy participants and peak pressures were located in the medial aspect of the forefoot in both groups. In contrast, RA participants had US detectable soft tissue pathology in the lateral aspect of the forefoot. Analysis of person specific data suggests that there are considerable variations over time with more than half the RA cohort having unstable presence of US detectable forefoot soft tissue pathology. Findings also indicated that, over time, changes in US detectable soft tissue pathology are out of phase with changes in foot-shoe interface pressures both temporally and spatially.Conclusions We found that US detectable forefoot soft tissue pathology may be unrelated to peak forefoot pressures and suggest that patients with RA may biomechanically adapt to soft tissue forefoot pathology. In addition, we have observed that, in patients with RA, interface foot-shoe pressures and the presence of US detectable forefoot pathology may vary substantially over time. This has implications for clinical strategies that aim to offload peak plantar pressures
- …