43,450 research outputs found
Application of residual feedback to lunar orbiter residual analysis Final report
Orbit determination of Lunar Orbiter using residual feedbac
Synthesis of titanium-containing ZSM-48
Titanium-containing ZSM-48 is synthesized with silicon to titanium ratios of 26 or larger; changes in unit cell volume and IR data show that titanium is incorporated into framework positions
Detailed Geant4 simulations of the ANITA and ANITA-CUP neutron facilities
Simulations of the ANITA spallation neutron source at The Svedberg Laboratory (TSL) are described. Neutron radiation calculations show close agreement with measurements at both standard and close user positions. Gamma radiation characteristics are also predicted
A comparative study of benchmarking approaches for non-domestic buildings: Part 1 ā Top-down approach
Benchmarking plays an important role in improving energy efficiency of non-domestic buildings. A review of energy benchmarks that underpin the UKās Display Energy Certificate (DEC) scheme have prompted necessities to explore the benefits and limitations of using various methods to derive energy benchmarks. The existing methods were reviewed and grouped into top-down and bottom-up approaches based on the granularity of the data used. In the study, two top-down methods, descriptive statistics and artificial neural networks (ANN), were explored for the purpose of benchmarking energy performances of schools. The results were used to understand the benefits of using these benchmarks for assessing energy efficiency of buildings and the limitations that affect the robustness of the derived benchmarks. Compared to the bottom-up approach, top-down approaches were found to be beneficial in gaining insight into how peers perform. The relative rather than absolute feedback on energy efficiency meant that peer pressure was a motivator for improvement. On the other hand, there were limitations with regard to the extent to which the energy efficiency of a building could be accurately assessed using the top-down benchmarks. Moreover, difficulties in acquiring adequate data were identified as a key limitation to using the top-down approach for benchmarking non-domestic buildings. The study suggested that there are benefits in rolling out of DECs to private sector buildings and that there is a need to explore more complex methods to provide more accurate indication of energy efficiency in non-domestic buildings
1.57 Ī¼m InGaAsP/InP surface emitting lasers by angled focus ion beam etching
The characteristics of 1.57 Ī¼m InGaAsP/InP surface emitting lasers based on an in-plan ridged structure and 45Ā° beam deflectors defined by angled focused ion beam (FIB) etching are reported. With an externally integrated beam deflector, threshold currents and emission spectra identical to conventional edge emitting lasers are achieved. These results show that FIB etching is a very promising technique for the definition of high quality mirrors and beam deflectors on semiconductor heterostructures for a variety of integrated optoelectronic devices
Higher Dimensional Operators in the MSSM
The origin and the implications of higher dimensional effective operators in
4-dimensional theories are discussed in non-supersymmetric and supersymmetric
cases. Particular attention is paid to the role of general,
derivative-dependent field redefinitions which one can employ to obtain a
simpler form of the effective Lagrangian. An application is provided for the
Minimal Supersymmetric Standard Model extended with dimension-five R-parity
conserving operators, to identify the minimal irreducible set of such operators
after supersymmetry breaking. Among the physical consequences of this set of
operators are the presence of corrections to the MSSM Higgs sector and the
generation of "wrong"-Higgs Yukawa couplings and fermion-fermion-scalar-scalar
interactions. These couplings have implications for supersymmetry searches at
the LHC.Comment: Contribution to the proceedings of the "Susy 2008" conference; (6
pages
A Note on Chiral Symmetry Breaking from Intersecting Branes
In this paper, we will consider the chiral symmetry breaking in the
holographic model constructed from the intersecting brane configuration, and
investigate the Nambu-Goldstone bosons associated with this symmetry breaking.Comment: 16 pp, minor changes, to appear PR
Low thrust orbit determination program
Logical flow and guidelines are provided for the construction of a low thrust orbit determination computer program. The program, tentatively called FRACAS (filter response analysis for continuously accelerating spacecraft), is capable of generating a reference low thrust trajectory, performing a linear covariance analysis of guidance and navigation processes, and analyzing trajectory nonlinearities in Monte Carlo fashion. The choice of trajectory, guidance and navigation models has been made after extensive literature surveys and investigation of previous software. A key part of program design relied upon experience gained in developing and using Martin Marietta Aerospace programs: TOPSEP (Targeting/Optimization for Solar Electric Propulsion), GODSEP (Guidance and Orbit Determination for SEP) and SIMSEP (Simulation of SEP)
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