Evaluate the application of modal test and analysis processes to structural fault detection in MSFC-STS project elements

The Space Transportation System (STS) is a very complex and expensive flight system which is intended to carry payloads into low Earth orbit and return. A catastrophic failure of the STS (such as experienced in the 51-L incident) results in the loss of both human life as well as very expensive hardware. One impact of this incident was to reaffirm the need to do everything possible to insure the integrity and reliability of the STS is sufficient to produce a safe flight. One means of achieving this goal is to expand the number of inspection technologies available for use on the STS. The purpose was to begin to evaluate the possible use of assessing the structural integrity of STS components for which Marshall Space Flight Center (MSFC) has responsibility. This entailed reviewing the available literature and determining a low-level experimental program which could be performed by MSFC and would help establish the feasibility of using this technology for structural fault detection

Potentials for soft wall AdS/QCD

Soft-wall models in AdS/QCD generally have dilaton and scalar fields that vary with the fifth-dimension coordinate. These fields can be parameterized to yield hadron mass spectra with linear radial trajectories and to incorporate spontaneous breaking of chiral symmetry. We show how to construct scalar potentials which lead to such solutions.Comment: 21 pages. Version 3 matches that accepted for publication. Typos have been corrected and references added. Substantial discussion has been added in order to clarify our approach and the issue of the dilaton mass in Sec. 4. Central results and conclusions remain unchanged

HP PRIME: product of research in mathematics education

The development of the HP Prime graphing calculator and wireless classroom was aided significantly by a core group of mathematics educators who advised the development team and a pedagogical architect who sat on the team. This paper reflects back on the design decisions they made and the research basis that shaped at least some of those decisions

Numerical simulation of the flow and fuel-air mixing in an axisymmetric piston-cylinder arrangement

The implicit factored method of Beam and Warming was employed to describe the flow and the fuel-air mixing in an axisymmetric piston-cylinder configuration during the intake and compression strokes. The governing equations were established on the basis of laminar flow. The increased mixing due to turbulence was simulated by appropriately chosen effective transport properties. Calculations were performed for single-component gases and for two-component gases and for two-component gas mixtures. The flow field was calculated as functions of time and position for different geometries, piston speeds, intake-charge-to-residual-gas-pressure ratios, and species mass fractions of the intake charge. Results are presented in graphical form which show the formation, growth, and break-up of those vortices which form during the intake stroke and the mixing of fuel and air throughout the intake and compression strokes. It is shown that at bore-to-stroke ratio of less than unity, the vortices may break-up during the intake stroke. It is also shown that vortices which do not break-up during the intake stroke coalesce during the compression stroke. The results generated were compared to existing numerical solutions and to available experimental data

Vortex motion in axisymmetric piston-cylinder configurations

By using the Beam and Warming implicit-factored method of solution of the Navier-Stokes equations, velocities were calculated inside axisymmetric piston cylinder configurations during the intake and compression strokes. Results are presented in graphical form which show the formation, growth and breakup of those vortices which form during the intake stroke by the jet issuing from the valve. It is shown that at bore-to-stroke ratio of less than unity, the vortices may breakup during the intake stroke. It is also shown that vortices which do not breakup during the intake stroke coalesce during the compression stroke

Noiseless Quantum Circuits for the Peres Separability Criterion

In this Letter we give a method for constructing sets of simple circuits that can determine the spectrum of a partially transposed density matrix, without requiring either a tomographically complete POVM or the addition of noise to make the spectrum non-negative. These circuits depend only on the dimension of the Hilbert space and are otherwise independent of the state.Comment: 4 pages RevTeX, 7 figures encapsulated postscript. v5: title changed slightly, more-or-less equivalent to the published versio

Study of an engine flow diverter system for a large scale ejector powered aircraft model

Requirements were established for a conceptual design study to analyze and design an engine flow diverter system and to include accommodations for an ejector system in an existing 3/4 scale fighter model equipped with YJ-79 engines. Model constraints were identified and cost-effective limited modification was proposed to accept the ejectors, ducting and flow diverter valves. Complete system performance was calculated and a versatile computer program capable of analyzing any ejector system was developed

Sound Mode Hydrodynamics from Bulk Scalar Fields

We study the hydrodynamic sound mode using gauge/gravity correspondence by examining a generic black brane background's response to perturbations. We assume that the background is generated by a single scalar field, and then generalize to the case of multiple scalar fields. The relevant differential equations obeyed by the gauge invariant variables are presented in both cases. Finally, we present an analytical solution to these equations in a special case; this solution allows us to determine the speed of sound and bulk viscosity for certain special metrics. These results may be useful in determining sound mode transport coefficients in phenomenologically motivated holographic models of strongly coupled systems.Comment: 17 pages. Corrections made to one of the gauge invariant equations (66). This equation was not used in the other main conclusions of the paper, so the rest of the results are unchange

Complexified sigma model and duality

We show that the equations of motion associated with a complexified sigma-model action do not admit manifest dual SO(n,n) symmetry. In the process we discover new type of numbers which we called `complexoids' in order to emphasize their close relation with both complex numbers and matroids. It turns out that the complexoids allow to consider the analogue of the complexified sigma-model action but with (1+1)-worldsheet metric, instead of Euclidean-worldsheet metric. Our observations can be useful for further developments of complexified quantum mechanics.Comment: 15 pages, Latex, improved versio