3,428 research outputs found
Finite Laguerre Near-planes of Odd Order Admitting Desarguesian Derivations
AbstractWe introduce finite Laguerre near-planes and investigate such planes of odd order that admit a Desarguesian derivation
Laguerre near-planes of order four
We investigate Laguerre near-planes of order 4 and classify all such planes. We further develop various descriptions of these planes and characterise those
Laguerre near-planes that can be extended to the Miquelian Laguerre plane. We also
determine the automorphism groups of these planes and give characterisations of
some of the planes in terms of their automorphism groups
The design and development of transonic multistage compressors
The development of the transonic multistage compressor is reviewed. Changing trends in design and performance parameters are noted. These changes are related to advances in compressor aerodynamics, computational fluid mechanics and other enabling technologies. The parameters normally given to the designer and those that need to be established during the design process are identified. Criteria and procedures used in the selection of these parameters are presented. The selection of tip speed, aerodynamic loading, flowpath geometry, incidence and deviation angles, blade/vane geometry, blade/vane solidity, stage reaction, aerodynamic blockage, inlet flow per unit annulus area, stage/overall velocity ratio, and aerodynamic losses are considered. Trends in these parameters both spanwise and axially through the machine are highlighted. The effects of flow mixing and methods for accounting for the mixing in the design process are discussed
Thermodynamic evidence for valley-dependent density of states in bulk bismuth
Electron-like carriers in bismuth are described by the Dirac Hamiltonian,
with a band mass becoming a thousandth of the bare electron mass along one
crystalline axis. The existence of three anisotropic valleys offers electrons
an additional degree of freedom, a subject of recent attention. Here, we map
the Landau spectrum by angle-resolved magnetostriction, and quantify the
carrier number in each valley: while the electron valleys keep identical
spectra, they substantially differ in their density of states at the Fermi
level. Thus, the electron fluid does not keep the rotational symmetry of the
lattice at low temperature and high magnetic field, even in the absence of
internal strain. This effect, reminiscent of the Coulomb pseudo-gap in
localized electronic states, affects only electrons in the immediate vicinity
of the Fermi level. It presents the most striking departure from the
non-interacting picture of electrons in bulk bismuth.Comment: 6 pages, 3 Figure
Data dependent energy modelling for worst case energy consumption analysis
Safely meeting Worst Case Energy Consumption (WCEC) criteria requires
accurate energy modeling of software. We investigate the impact of instruction
operand values upon energy consumption in cacheless embedded processors.
Existing instruction-level energy models typically use measurements from random
input data, providing estimates unsuitable for safe WCEC analysis.
We examine probabilistic energy distributions of instructions and propose a
model for composing instruction sequences using distributions, enabling WCEC
analysis on program basic blocks. The worst case is predicted with statistical
analysis. Further, we verify that the energy of embedded benchmarks can be
characterised as a distribution, and compare our proposed technique with other
methods of estimating energy consumption
Supersonic through-flow fan design
The NASA Lewis Research Center has embarked on a program to experimentally prove the concept of a supersonic through-flow fan which is to maintain supersonic velocities throughout the compression system with only weak shock-wave flow losses. The detailed design of a supersonic through-flow fan and estimated off-design performance with the use of advanced computational codes are described. A multistage compressor facility is being modified for the newly designed supersonic through-flow fan and the major aspects of this modification are briefly described
Energy Functionals for Manifold-valued Mappings and Their Properties
This technical report is merely an extended version of the appendix of Steinke et.al. "Manifold-valued Thin-Plate Splines with Applications in Computer Graphics" (2008) with complete proofs, which had to be omitted due to space restrictions. This technical report requires a basic knowledge of differential geometry. However, apart from that requirement the technical report is self-contained
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