5,756 research outputs found
Metabolic production of carbon dioxide in simulated sea states: relevance for hyperbaric escape systems
Component specific modeling
The objective was to develop and verify a series of interdisciplinary modeling and analysis techniques specialized to address hot section components. These techniques incorporate data as well as theoretical methods from many diverse areas, including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis
Component specific modeling
The objective is to develop and verify a series of interdisciplinary modeling and analysis techniques that have been specialized to address three specific hot section components. These techniques will incorporate data as well as theoretical methods from many diverse areas including cycle and performance analysis, heat transfer analysis, linear and nonlinear stress analysis, and mission analysis. The new methods developed will be integrated to provide an accurate, efficient, and unified approach to analyzing combustor burner liners, hollow air-cooled turbine blades, and air-colled turbine vanes. For these components, the methods developed will predict temperature, deformation, stress, and strain histories throughout a complete flight mission
Multiplier Sequences for Simple Sets of Polynomials
In this paper we give a new characterization of simple sets of polynomials B
with the property that the set of B-multiplier sequences contains all
Q-multiplier sequence for every simple set Q. We characterize sequences of real
numbers which are multiplier sequences for every simple set Q, and obtain some
results toward the partitioning of the set of classical multiplier sequences
Fatigue Behavior of IM7/BMI 5250-4 Composite at Room and Elevated Temperatures
The tension-tension fatigue and tension-compression fatigue behaviors of the IM7/BMI 5250-4 composite were investigated. The tension-tension fatigue of the composite with 0/90 and ±45 fiber orientations was studied at 23, 170, and 190°C. The tension-compression fatigue of the composite with 0/90 fiber orientation was examined at 23°C. The tensile and compressive properties of the composite were also evaluated at room and elevated temperatures for both 0/90 and ±45 fiber orientations. Elevated temperature had little effect on the tensile properties of the 0/90 fiber orientation, but strongly influenced the ±45 tensile properties as well as the compressive properties of both fiber orientations. The 0/90 cross-ply exhibited a much stronger tension-tension fatigue performance than the ±45 cross-ply. Elevated temperature had little influence on the tension-tension fatigue response of both fiber orientations. The 0/90 composite exhibited reduced fatigue lives under tension-compression fatigue compared to the tension-tension cycling. The increased influence of the matrix on tension-compression fatigue response is evident
Response maxima in time-modulated turbulence: Direct Numerical Simulations
The response of turbulent flow to time-modulated forcing is studied by direct
numerical simulations of the Navier-Stokes equations. The large-scale forcing
is modulated via periodic energy input variations at frequency . The
response is maximal for frequencies in the range of the inverse of the large
eddy turnover time, confirming the mean-field predictions of von der Heydt,
Grossmann and Lohse (Phys. Rev. E 67, 046308 (2003)). In accordance with the
theory the response maximum shows only a small dependence on the Reynolds
number and is also quite insensitive to the particular flow-quantity that is
monitored, e.g., kinetic energy, dissipation-rate, or Taylor-Reynolds number.
At sufficiently high frequencies the amplitude of the kinetic energy response
decreases as . For frequencies beyond the range of maximal response,
a significant change in phase-shift relative to the time-modulated forcing is
observed.Comment: submitted to Europhysics Letters (EPL), 8 pages, 8 Postscript
figures, uses epl.cl
Component-specific modeling
Accomplishments are described for a 3 year program to develop methodology for component-specific modeling of aircraft hot section components (turbine blades, turbine vanes, and burner liners). These accomplishments include: (1) engine thermodynamic and mission models, (2) geometry model generators, (3) remeshing, (4) specialty three-dimensional inelastic structural analysis, (5) computationally efficient solvers, (6) adaptive solution strategies, (7) engine performance parameters/component response variables decomposition and synthesis, (8) integrated software architecture and development, and (9) validation cases for software developed
Expression, Purification, Crystallization and Preliminary X-Ray Analysis of \u3cem\u3ePseudomonas aeuginosa\u3c/em\u3e AlgX
AlgX is a periplasmic protein required for the production of the exopolysaccharide alginate in Pseudomonas sp. and Azotobacter vinelandii. AlgX has been overexpressed and purified and diffraction-quality crystals have been grown using iterative seeding and the hanging-drop vapor-diffusion method. The crystals grew as flat plates with unit-cell parameters a=46.4, b=120.6, c=86.9Å, β=95.7°. The cyrstals exhibited the symmetry of space group P21 and diffracted to a minimimum d-spacing of 2.1Å. On the basis of the Matthews coefficient (VM=2.25Å3 Da-1), two molecules were estimated to be present in the asymmetric unit
Tea
This publication provides a brief crop profile for tea, information on world supply and demand, and notes on tea in Hawaii
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