8,841 research outputs found
Appendix - Some spectroscopic observations of the interaction between a plasma wind and a dipole magnetic field
Spectroscopic studies on seeded plasma interaction with magnetic dipole fiel
Quantum Field Theory of Open Spin Networks and New Spin Foam Models
We describe how a spin-foam state sum model can be reformulated as a quantum
field theory of spin networks, such that the Feynman diagrams of that field
theory are the spin-foam amplitudes. In the case of open spin networks, we
obtain a new type of state-sum models, which we call the matter spin foam
models. In this type of state-sum models, one labels both the faces and the
edges of the dual two-complex for a manifold triangulation with the simple
objects from a tensor category. In the case of Lie groups, such a model
corresponds to a quantization of a theory whose fields are the principal bundle
connection and the sections of the associated vector bundles. We briefly
discuss the relevance of the matter spin foam models for quantum gravity and
for topological quantum field theories.Comment: 13 pages, based on the talk given at the X-th Oporto Meeting on
Geometry, Physics and Topology, Porto, September 20-24, 200
Information extraction techniques for multispectral scanner data
The applicability of recognition-processing procedures for multispectral scanner data from areas and conditions used for programming the recognition computers to other data from different areas viewed under different measurement conditions was studied. The reflective spectral region approximately 0.3 to 3.0 micrometers is considered. A potential application of such techniques is in conducting area surveys. Work in three general areas is reported: (1) Nature of sources of systematic variation in multispectral scanner radiation signals, (2) An investigation of various techniques for overcoming systematic variations in scanner data; (3) The use of decision rules based upon empirical distributions of scanner signals rather than upon the usually assumed multivariate normal (Gaussian) signal distributions
Discrimination techniques employing both reflective and thermal multispectral signals
Recent improvements in remote sensor technology carry implications for data processing. Multispectral line scanners now exist that can collect data simultaneously and in registration in multiple channels at both reflective and thermal (emissive) wavelengths. Progress in dealing with two resultant recognition processing problems is discussed: (1) More channels mean higher processing costs; to combat these costs, a new and faster procedure for selecting subsets of channels has been developed. (2) Differences between thermal and reflective characteristics influence recognition processing; to illustrate the magnitude of these differences, some explanatory calculations are presented. Also introduced, is a different way to process multispectral scanner data, namely, radiation balance mapping and related procedures. Techniques and potentials are discussed and examples presented
Thermal conductivity of heterogeneous mixtures and lunar soils
The theoretical evaluation of the effective thermal conductivity of granular materials is discussed with emphasis upon the heat transport properties of lunar soil. The following types of models are compared: probabilistic, parallel isotherm, stochastic, lunar, and a model based on nonlinear heat flow system synthesis
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The narrative coherence of witness transcripts in children on the autism spectrum
Background and Aims. Autistic children often recall fewer details about witnessed events than typically developing children (of comparable age and ability), although the information they recall is generally no less accurate. Previous research has not examined the narrative coherence of such accounts, despite higher quality narratives potentially being perceived more favourably by criminal justice professionals and juries. This study compared the narrative coherence of witness transcripts produced by autistic and typically developing (TD) children (ages 6-11 years, IQs 70+).
Methods and Procedures. Secondary analysis was carried out on interview transcripts from a subset of 104 participants (autism=52, TD=52) who had taken part in a larger study of eyewitness skills in autistic and TD children. Groups were matched on chronological age, IQ and receptive language ability. Coding frameworks were adopted from existing narrative research, featuring elements of ‘story grammar’.
Outcomes and Results. Whilst fewer event details were reported by autistic children, there were no group differences in narrative coherence (number and diversity of ‘story grammar’ elements used), narrative length or semantic diversity.
Conclusions and Implications. These findings suggest that the narrative coherence of autistic children’s witness accounts is equivalent to TD peers of comparable age and ability
Micro-Switches with Sputtered Au, AuPd, Au-on-AuPt, and AuPtCu Alloy Electric Contacts
This work is the first to report on a new analytic model for predicting micro-contact resistance and the design, fabrication, and testing of microelectromechanical systems (MEMS) metal contact switches with sputtered bi-metallic (i.e. gold (Au)-on-Au-platinum (Pt), (Au-on-Au-(6%)Pt)), binary alloy (i.e. Au-palladium (Pd), (Au-(2%)Pd)), and tertiary alloy (i.e. Au-Pt-copper (Cu), (Au-(5%)Pt-(0.5%)Cu)) electric contacts. The micro-switches with bi-metallic and binary alloy contacts resulted in contact resistance between 1-2 /spl Omega/ and, when compared to micro-switches with sputtered Au electric contacts, exhibited a 3.3 and 2.6 times increase in switching lifetime, respectively. The tertiary alloy exhibited a 6.5 times increase in switch lifetime with contact resistance ranging from 0.2-1.8 /spl Omega/
Four dimensional topological quantum field theory, Hopf categories, and the canonical bases
We propose a new mwthod of constructing 4D-TQFTs. The method uses a new type
of algebraic structure called a Hopf Category. We also outline the construction
of a family of Hopf categories related to the quantum groups, using the
canonical bases.Comment: 38 page
Selective formation of copper nanoparticles from acid mine drainage using nanoscale zerovalent iron particles
Nanoscale zerovalent iron (nZVI) has been investigated for the selective formation of Cu nanoparticles from acid mine drainage (AMD) taken from a legacy mine site in the UK. Batch experiments were conducted containing unbuffered (pH 2.67 at t=0) and pH buffered (pH 99.9% removal of all metals within 1 h when nZVI ≥1.0 g/L) from unbuffered AMD despite the coexistent of numerous other metals in the AMD, namely: Na, Ca, Mg, K, Mn and Zn. An acidic pH buffer enabled similarly high Cu removal but maximum removal of only <1.5% and <0.5% Cd and Al respectively. HRTEM-EDS confirmed the formation of discrete spherical nanoparticles comprised of up to 68% wt. Cu, with a relatively narrow size distribution (typically 20-100 nm diameter). XPS confirmed such nanoparticles as containing Cu0 , with the Cu removal mechanism therefore likely via cementation with Fe0 . Overall the results demonstrate nZVI as effective for the one-pot and selective formation of Cu0 -bearing nanoparticles from acidic wastewater, with the technique therefore potentially highly useful for the selective upcycling of dissolved Cu in wastewater into high value nanomaterials
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