Heat sensing instrument Patent

Heat sensing instrument, using thermocouple junction connected under heavy conducting materia

Silicon halide-alkali metal flames as a source of solar grade silicon

The feasibility of using alkali metal-silicon halide diffusion flames to produce solar-grade silicon in large quantities and at low cost is demonstrated. Prior work shows that these flames are stable and that relatively high purity silicon can be produced using Na + SiCl4 flames. Silicon of similar purity is obtained from Na + SiF4 flames although yields are lower and product separation and collection are less thermochemically favored. Continuous separation of silicon from the byproduct alkali salt was demonstrated in a heated graphite reactor. The process was scaled up to reduce heat losses and to produce larger samples of silicon. Reagent delivery systems, scaled by a factor of 25, were built and operated at a production rate of 0.5 kg Si/h. Very rapid reactor heating rates are observed with wall temperatures reaching greater than 2000 K. Heat release parameters were measured using a cooled stainless steel reactor tube. A new reactor was designed

Instrument accurately measures small temperature changes on test surface

Calorimeter apparatus accurately measures very small temperature rises on a test surface subjected to aerodynamic heating. A continuous thin sheet of a sensing material is attached to a base support plate through which a series of holes of known diameter have been drilled for attaching thermocouples to the material

Locally Equivalent Correspondences

Given a pair of number fields with isomorphic rings of adeles, we construct bijections between objects associated to the pair. For instance we construct an isomorphism of Brauer groups that commutes with restriction. We additionally construct bijections between central simple algebras, maximal orders, various Galois cohomology sets, and commensurability classes of arithmetic lattices in simple, inner algebraic groups. We show that under certain conditions, lattices corresponding to one another under our bijections have the same covolume and pro-congruence completion. We also make effective a finiteness result of Prasad and Rapinchuk.Comment: Final Version. To appear in Ann. Inst. Fourie

Small representations, string instantons, and Fourier modes of Eisenstein series (with an appendix by D. Ciubotaru and P. Trapa)

This paper concerns some novel features of maximal parabolic Eisenstein series at certain special values of their analytic parameter s. These series arise as coefficients in the R4 and D4R4 interactions in the low energy expansion of scattering amplitudes in maximally supersymmetric string theory reduced to D=10-d dimensions on a torus T^d, d<8. For each d these amplitudes are automorphic functions on the rank d+1 symmetry group E_d+1. Of particular significance is the orbit content of the Fourier modes of these series when expanded in three different parabolic subgroups, corresponding to certain limits of string theory. This is of interest in the classification of a variety of instantons that correspond to minimal or next-to-minimal BPS orbits. In the limit of decompactification from D to D+1 dimensions many such instantons are related to charged 1/2-BPS or 1/4-BPS black holes with euclidean world-lines wrapped around the large dimension. In a different limit the instantons give nonperturbative corrections to string perturbation theory, while in a third limit they describe nonperturbative contributions in eleven-dimensional supergravity. A proof is given that these three distinct Fourier expansions have certain vanishing coefficients that are expected from string theory. In particular, the Eisenstein series for these special values of s have markedly fewer Fourier coefficients than typical ones. The corresponding mathematics involves showing that the wavefront sets of the Eisenstein series are supported on only certain coadjoint nilpotent orbits - just the minimal and trivial orbits in the 1/2-BPS case, and just the next-to-minimal, minimal and trivial orbits in the 1/4-BPS case. Thus as a byproduct we demonstrate that the next-to-minimal representations occur automorphically for E6, E7, and E8, and hence the first two nontrivial low energy coefficients are exotic theta-functions.Comment: v3: 127 pp. Minor changes. Final version to appear in the Special Issue in honor of Professor Steve Ralli

Resolving ambiguities in mass determinations at future colliders

The measurements of kinematical endpoints, in cascade decays of supersymmetric particles, in principle allow for a determination of the masses of the unstable particles. However, in this procedure ambiguities often arise. We here illustrate how such ambiguities arise. They can be resolved by a precise determination of the LSP mass, provided by the Linear Collider.Comment: 6 pages, 6 figures, to appear in the proceedings of the 2005 International Linear Collider Workshop, Stanford, U.S.

1,2-Dimethyl-4,5-diphenylbenzene determined on a Bruker SMART X2S benchtop crystallographic system

The title compound, C(20)H(18), has two crystallographically independent molecules in the asymmetric unit. The phenyl substituents of molecule A are twisted away from the plane defined by the central benzene ring by 131.8 (2) and -52.7 (3)degrees. The phenyl substituents of molecule B are twisted by -133.3 (2) and 50.9 (3)degrees. Each molecule is stabilized by a pair of intraMolecular C(aryl, sp(2))-H center dot center dot center dot pi interactions, as well as by several interMolecular C(methyl, sp(3))-H center dot center dot center dot pi interactions

Status of advanced turboprop technology

Research is reviewed in the following areas: turboprop powered transport aircraft; wind tunnel aerodynamic and acoustics tests of model propellers; turboprop maintenance; and wind tunnel tests on airframe-turboprop interactions. Continued development of the technology for advanced turboprop transport was emphasized