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Sep 20, 2010
09/10

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NON

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The User's Manual is one of four manuals that constitute the documentation for NASTRAN, the other three being the Theoretical Manual, the Programmer's Manual and the Demonstration Problem Manual. Although the User's Manual contains all of the information that is directly associated with the solution of problems with NASTRAN, the user will find it desirable to refer to the other manuals for assistance in the solution of specific user problems. The Theoretical Manual gives an excellent...

Topics: ALGORITHMS, COMPUTERIZED SIMULATION, DYNAMIC RESPONSE, FINITE ELEMENT METHOD, PARTIAL DIFFERENTIAL...

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Jul 11, 2010
07/10

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NON

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This two volume publication presents the proceedings of the third through sixth history symposia of the International Academy of Astronautics. Thirty-nine papers are divided into four categories: (1) Early Solid Propellant Rocketry; (2) Rocketry and Astronautics: Concepts, Theory, and Analyses after 1880; (3) The Development of Liquid and Solid Propellant Rockets from 1880 to 1945; and (4) Rocketry and Astronautics after 1945. Categories 1 and 2 will be found in volume 1 and the remainder in...

Topics: ALGORITHMS, LEAST SQUARES METHOD, MATRICES (MATHEMATICS), MATHEMATICAL MODELS, ORTHOGONAL...

2,530
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Jun 21, 2010
06/10

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NON

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Space Programs Summary - supporting research and advanced development

Topics: CONTROL, INDUSTRIES, SYSTEMS ENGINEERING, EQUILIBRIUM, MATHEMATICAL MODELS, MATRICES (MATHEMATICS),...

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Sep 20, 2010
09/10

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NON

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The Office of Exploration (OEXP) at NASA Headquarters was tasked with defining and recommending alternatives for an early 1990's national decision on a focused program of human exploration of the solar system. The Mission Analysis and System Engineering (MASE) group, which is managed by the Exploration Studies Office at JSC, is responsible for coordinating the technical studies necessary for accomplishing such a task. This technical report, produced by the MASE, describes the process that was...

Topics: ALGORITHMS, VARIABILITY, CALIBRATING, COMPUTER PROGRAMS, ENERGY SPECTRA, GAMMA RAY BURSTS, SPECTRUM...

1,748
1.7K

Sep 20, 2010
09/10

by
Fries, Sylvia Dought

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A historical account of NASA's Apollo era engineers is presented. This book is based on interviews that were conducted with fifty-one 'typical' engineers.

Topics: COEFFICIENTS, HYPERBOLAS, IMAGE PROCESSING, MATRICES (MATHEMATICS), PARABOLAS, PARALLELEPIPEDS,...

1,520
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Jul 12, 2010
07/10

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NON

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NASTRAN is a large, comprehensive, nonproprietary, general purpose finite element computer code for structural analysis. The Twelfth Users' Colloquim provides some comprehensive papers on the application of finite element methods in engineering, comparisons with other approaches, unique applications, pre and post processing or auxiliary programs, and new methods of analysis with NASTRAN.

Topics: ARTIFICIAL INTELLIGENCE, JOINTS (JUNCTIONS), MAN MACHINE SYSTEMS, MATRICES (MATHEMATICS), VISUAL...

832
832

Jun 21, 2010
06/10

by
Henry, R. E

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Compressible flow of two component, two phase mixtures in nozzles and orifices

Topics: BOUNDARY VALUE PROBLEMS, NEWTON METHODS, NEWTON THEORY, NONLINEAR EQUATIONS, DIFFERENTIAL...

822
822

Jul 6, 2010
07/10

by
Jessee, R. D

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This report covers the design and development of the laboratory model, and is essentially a compilation of reports covering the system and its various parts. To enhance completeness, the final report of Phase 1 covering circuit development of the controller is also included. A controller was developed for a brushless, direct-drive, single axis solar array reorientation system for earth-pointed, passively-stabilized spacecraft. A control systems was designed and breadboard circuits were built...

Topics: DIFFERENTIAL EQUATIONS, LIAPUNOV FUNCTIONS, LINEAR EQUATIONS, PROBLEM SOLVING, MATRICES...

813
813

Jul 21, 2010
07/10

by
Lan, C. E

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Flow field data for a double delta wing at low speed were used to determine the location of a vortex action point. The result was found to be consistent with what was determined for a delta wing. In supersonic flow, the action point location was determined empirically. For a wing with rounded leading edges, an assumption for initial vortex separation was shown to be equivalent to initial leading edge bubble separation for airfoils. A theoretical formulation by the section analogy to determine...

Topics: AERODYNAMIC BALANCE, MATRICES (MATHEMATICS), PILOT PERFORMANCE, REACTION TIME, RUDDERS, STEADY...

782
782

Jul 26, 2010
07/10

by
Long, W. C

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The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA effort first completed and analysis of the Communication and Tracking hardware, generating draft failure modes and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to the NASA FMEA/CIL...

Topics: ALGORITHMS, WEIGHTING FUNCTIONS, ANTENNA ARRAYS, ANTENNAS, RADIO FREQUENCY INTERFERENCE, SIGNAL...

718
718

Jul 11, 2010
07/10

by
White, R. G

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An investigation of the moments and probability distribution of the resultant of two normally distributed random variables is presented. This is the so-called generalized Rayleigh distribution which has many applications in the study of wind shear, random noise, and radar. The most general formula was derived, and two special cases were considered for which tables of the moments and probability distribution functions are included as an appendix. One of the special cases was generalized to...

Topics: APOLLO PROJECT, PERFORMANCE PREDICTION, REENTRY TRAJECTORIES, SPACECRAFT GUIDANCE, MATHEMATICAL...

683
683

Jul 12, 2010
07/10

by
Keiter, I. D

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Studies of several General Aviation aircraft indicated that the application of advanced technologies to General Aviation propellers can reduce fuel consumption in future aircraft by a significant amount. Propeller blade weight reductions achieved through the use of composites, propeller efficiency and noise improvements achieved through the use of advanced concepts and improved propeller analytical design methods result in aircraft with lower operating cost, acquisition cost and gross weight.

Topics: CONTROL THEORY, MATRICES (MATHEMATICS), PARAMETER IDENTIFICATION, ERROR DETECTION CODES, FLIGHT...

672
672

Jul 23, 2010
07/10

by
Scholz, A. L.; Hart, M. T.; Lowry, D. J

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The Technology Information Sheet was assembled in database format during Phase I. This document was designed to provide a repository for information pertaining to 144 Operations and Maintenance Instructions (OMI) controlled operations in the Orbiter Processing Facility (OPF), Vehicle Assembly Building (VAB), and PAD. It provides a way to accumulate information about required crew sizes, operations task time duration (serial and/or parallel), special Ground Support Equipment (GSE). required, and...

Topics: ALGORITHMS, LINEAR SYSTEMS, MATRICES (MATHEMATICS), STOCHASTIC PROCESSES, CONTROLLABILITY,...

In this work, the results of calculations of energy levels and transition probabilities for the lanthanides in CaWO4 is reported. This material was one of the earlier laser host materials, and an abundance of experimental data are available, for comparison with our calculations on the energy levels and electric dipole transition probabilities for the triply ionized lanthanides from Pr to Tm.

Topics: DTIC Archive, Wortman,Donald E, HARRY DIAMOND LABS ADELPHI MD, *LATTICE DYNAMICS, *CALCIUM...

653
653

Jul 21, 2010
07/10

by
Slivinski, T.; Broglio, C.; Wild, C.; Goldberg, J.; Levitt, K.; Hitt, E.; Webb, J

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Presented is an overview of the current state of the art of fault-tolerant software and an analysis of quantitative techniques and models developed to assess its impact. It examines research efforts as well as experience gained from commercial application of these techniques. The paper also addresses the computer architecture and design implications on hardware, operating systems and programming languages (including Ada) of using fault-tolerant software in real-time aerospace applications. It...

Topics: ALGEBRA, NONLINEAR SYSTEMS, PARTIAL DIFFERENTIAL EQUATIONS, STRUCTURAL ANALYSIS, STRUCTURAL...

641
641

Jun 21, 2010
06/10

by
NON

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Development of radiation sensor subsystems for advanced manned space missions

Topics: MATRICES (MATHEMATICS), MULTIPOLES, S MATRIX THEORY, MICROWAVE CIRCUITS

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627

Sep 20, 2010
09/10

by
Sloan, Alan D

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A deterministic fractal is an image which has low information content and no inherent scale. Because of their low information content, deterministic fractals can be described with small data sets. They can be displayed at high resolution since they are not bound by an inherent scale. A remarkable consequence follows. Fractal images can be encoded at very high compression ratios. This fern, for example is encoded in less than 50 bytes and yet can be displayed at resolutions with increasing...

Topics: AMPLIFICATION, KALMAN FILTERS, LINEAR FILTERS, MIMO (CONTROL SYSTEMS), SCALARS, MATRICES...

A collection of mathematical problems related to NASA space science projects is presented. In developing the examples and problems, attention was given to preserving the authenticity and significance of the original setting while keeping the level of mathematics within the secondary school curriculum. Computation and measurement, algebra, geometry, probability and statistics, exponential and logarithmic functions, trigonometry, matrix algebra, conic sections, and calculus are among the areas...

Topics: NASA Technical Reports Server (NTRS), AEROSPACE SCIENCES, EDUCATION, MATHEMATICS, ALGEBRA,...

593
593

Jul 6, 2010
07/10

by
Deloatch, E. M

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The five problems studied for biomedical applications of NASA technology are reported. The studies reported are: design modification of electrophoretic equipment, operating room environment control, hematological viscometry, handling system for iridium, and indirect blood pressure measuring device.

Topics: DIFFERENTIAL EQUATIONS, LINEAR SYSTEMS, OSCILLATIONS, EIGENVALUES, LEBESGUE THEOREM, MATRICES...

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565

Jul 12, 2010
07/10

by
NON

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The state of the art in nuclear pumped lasers is reviewed. Nuclear pumped laser modeling, nuclear volume and foil excitation of laser plasmas, proton beam simulations, nuclear flashlamp excitation, and reactor laser systems studies are covered.

Topics: COMPUTER SYSTEMS PROGRAMS, EQUATIONS OF MOTION, MATRICES (MATHEMATICS), AERODYNAMIC DRAG,...

542
542

Jul 12, 2010
07/10

by
Lidiak, E. G

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Data acquisition and evaluation, basement geologic provinces, basement ages and tectonic provinces, configuration of the basement surface, and various abstracts and preprints are provided.

Topics: COMPUTATION, CONSTANTS, MEROMORPHIC FUNCTIONS, POWER SERIES, SERIES EXPANSION, CAUCHY INTEGRAL...

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508

May 31, 2011
05/11

by
Camanho, P. P.; Davila, C. G.; Ambur, D. R

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The use of decohesion elements for the simulation of delamination in composite materials is reviewed. The test methods available to measure the interfacial fracture toughness used in the formulation of decohesion elements are described initially. After a brief presentation of the virtual crack closure technique, the technique most widely used to simulate delamination growth, the formulation of interfacial decohesion elements is described. Problems related with decohesion element constitutive...

Topics: PROLATE SPHEROIDS, SPHERES, SCATTERING, MATRICES (MATHEMATICS), CIRCULAR CYLINDERS, BACKSCATTERING,...

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482

Jul 25, 2010
07/10

by
Cetinkunt, Sabr

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A general gross and fine motion planning and control strategy is needed for lightweight robotic manipulator applications such as painting, welding, material handling, surface finishing, and spacecraft servicing. The control problem of lightweight manipulators is to perform fast, accurate, and robust motions despite the payload variations, structural flexibility, and other environmental disturbances. Performance of the rigid manipulator model based computed torque and decoupled joint control...

Topics: ATOMIC STRUCTURE, ULTRAVIOLET SPECTRA, CYANIDES, DISSOCIATION, MATRICES (MATHEMATICS), QUANTUM...

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467

May 23, 2011
05/11

by
Knight, Doyle D

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A computational study of the crossing shock wave-turbulent boundary layer interaction is presented. The shock waves are generated by a pair of fins which are mounted normal to a flat plate and form a converging channel. The focus of the study is to investigate the ability of the theoretical turbulence model to provide for improvement in the predictions of adiabatic wall temperature and heat transfer rates during the interaction of the shock waves with the turbulent boundary layer on the flat...

Topics: HANKEL FUNCTIONS, TIME DEPENDENCE, INVARIANCE, SINGULARITY (MATHEMATICS), FLEXIBLE BODIES,...

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451

Jul 10, 2010
07/10

by
Robinson, F

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A test program was conducted to isolate and evaluate the individual noise sources of a light helicopter. To accomplish this, the helicopter was mounted on a special test rig, at a 6-foot skid height, in a simulated hover. The test rig contained by dynamometer for absorbing engine power and an exhaust silencing system for reducing engine noise. This test set-up allowed the various components of the helicopter to be run and listened to individually or in any combination. The sound pressure level...

Topics: LIGHT SCATTERING, POLARIZATION (WAVES), SEA WATER, MATRICES (MATHEMATICS), SCATTERING COEFFICIENTS

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445

Jul 26, 2010
07/10

by
Belcastro, Celeste M

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Control systems for advanced aircraft, especially those with relaxed static stability, will be critical to flight and will, therefore, have very high reliability specifications which must be met for adverse as well as nominal operating conditions. Adverse conditions can result from electromagnetic disturbances caused by lightning, high energy radio frequency transmitters, and nuclear electromagnetic pulses. Tools and techniques must be developed to verify the integrity of the control system in...

Topics: ADAPTIVE CONTROL, BOUNDARY VALUE PROBLEMS, CONTROL SYSTEMS DESIGN, MATHEMATICAL MODELS, ON-LINE...

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438

Jun 3, 2011
06/11

by
Ritchie, Stephen M. C.; Luo, Qiang; Curtis, Salina S.; Holladay, Jon B.; Clark, Dallas W

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Liquid coolants are commonly used as thermal transport media to increase efficiency and flexibility in aerospace vehicle design. The introduction of gas bubbles into the coolant can have negative consequences, including: loss of centrifugal pump prime, irregular sensor readings, and blockage of coolant flow to remote systems. One solution to mitigate these problems is the development of a passive gas removal device, or gas trap, installed in the flight cooling system. In this study, a new...

Topics: FLIGHT CONTROL, CONTROL SYSTEMS DESIGN, F-16 AIRCRAFT, LINEAR PARAMETER-VARYING CONTROL, AUTOMATIC...

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433

May 23, 2011
05/11

by
Perry, J. L.; Graf, J. C

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Air quality is an important consideration not only for the external environment, but also for the indoor environment. Most people spend a majority of their lives indoors and the air that they breathe is important to their physical and emotional well being. Since most modern building designs have focused on energy efficiency, less fresh air is brought from the outside. As a result, pollutants from building materials, furniture, cleaning, and cooking have no place to go. To make matters worse,...

Topics: FREQUENCY RESPONSE, SYSTEM IDENTIFICATION, APPLICATIONS PROGRAMS (COMPUTERS), SPECTRUM ANALYSIS,...

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423

Jul 6, 2010
07/10

by
RYLOV, Y. A

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IT IS SHOWN THAT NONRELATIVISTIC QUANTUM MECHANICS OF TWO PARTICLES INTERACTING WITH AN EXTERNAL ELECTROMAGNETIC FIELD AND WITH EACH OTHER CAN BE CONSIDERED AS THE STATISTICS OF TWO-DIMENSIONAL SURFACES REPRESENTING THE STATE OF THE SYSTEM CONSISTING OF TWO NONDETERMINISTIC PARTICLES IN EIGHT-DIMENSIONAL SPACE. THIS SPACE IS THE DIRECT PRODUCT OF THE SPACE-TIMES FOR EACH PARTICLE.

Topics: CATHODE RAY TUBES, DATA PROCESSING, DISPLAY DEVICES, HUMAN PERFORMANCE, COMPUTERIZED SIMULATION,...

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413

Jul 11, 2010
07/10

by
Lahzun, J

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The command and data acquisition (CDA) station for the Synchronous Meteorological Satellite (SMS) program, located on the Eastern shore of Virginia, is described in terms of facility layout, ground support instrumentation, and capabilities. Data systems and equipment are described in detailed block diagrams. The major subsystems are identified and information on equipment specifications, frequency ranges, and data processing format is given. Automatic picture transmission, data utilization...

Topics: CODERS, INFORMATION THEORY, TRANSFORMATIONS (MATHEMATICS), COMMAND AND CONTROL, MATRICES...

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401

Jul 11, 2010
07/10

by
HUETTER, U

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SHELL STRUCTURES FOR PROPELLERS AND HELICOPTER BLADES ARE PREDOMINANTLY UNDER CENTRIFUGAL LOADS AND THEREFORE ESSENTIALLY SUBJECTED TO SUCH EXTENSIVE RADIAL STRESSES THAT FULL ADVANTAGE CAN BE TAKEN OF THE HIGH TENSILE STRENGTH OF STRAND-REINFORCED SYNTHETIC RESIN MATERIALS. GREAT DIFFICULTIES HAVE BEEN ENCOUNTERED IN THE PAST WITH THE DIFFUSION OF END LOADS INTO FIBERGLASS REINFORCED COMPOUND MATERIALS. THESE DIFFICULTIES, HOWEVER, CAN BE OVERCOME BY APPLYING THE LOOP METHOD, A METHOD BY WHICH...

Topics: ASYMPTOTES, DIFFERENTIAL EQUATIONS, LINEAR SYSTEMS, LINEAR EQUATIONS, MATRICES (MATHEMATICS), TIME...

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398

Jul 11, 2010
07/10

by
ARGYRIS, J. H.; LOCHNER, N. M.; SCHARPF, D. W

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THE APPLICATION OF THE MATRIX THEORY OF STATICS AND DYNAMICS TO THE CALCULATION OF NATURAL MODES OF OSCILLATION OF ROTOR BLADES IS DESCRIBED. THE BASIC PRINCIPLES OF THE MATRIX DISPLACEMENT METHOD ARE SUMMARIZED. THE IDEALIZED ROTOR BLADE IS BROKEN DOWN INTO ELEMENTS; THEIR ELASTIC REGIDITIES AND KINEMATICALLY EQUIVALENT POINT FORCES AND MOMENTS APPLIED TO NODES, RATHER THAN BEING DISTRIBUTED, ARE DERIVED. THE CORRESPONDING KINEMATICALLY EQUIVALENT MASS MATRIX IS ALSO OBTAINED. THESE AND...

Topics: ARTIFICIAL SATELLITES, ALGORITHMS, MATRICES (MATHEMATICS), SATELLITE ORIENTATION

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396

Jun 21, 2010
06/10

by
Denardo, B. P

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Projectile shape effects on hypervelocity impact craters in aluminum

Topics: FORMULAS (MATHEMATICS), INDEPENDENT VARIABLES, POLYNOMIALS, SMOOTHING, COMPUTER PROGRAMS, IBM 7094...

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389

Jul 11, 2010
07/10

by
NON

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No Abstract Available

Topics: MATRICES (MATHEMATICS), MULTIPLICATION, THEOREM PROVING, ALGEBRA, OPERATORS (MATHEMATICS)

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387

Jun 21, 2010
06/10

by
Akyuz, F. A.; Utku, S

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ELAS general purpose digital computer program for equilibrium problems of linear structures

Topics: COMPUTER PROGRAMMING, INPUT, MATHEMATICAL MODELS, MATRICES (MATHEMATICS), OUTPUT, PUNCHED CARDS,...

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383

Jul 23, 2010
07/10

by
Hashimoto, R.; Nagamatsu, A.; Michimura, S

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The vibration of the rotating disk is analyzed using the finite element method with consideration given to the effect of centrifugal force. A fan-shaped element is proposed for the first time for the analysis of both in-plane and bending deformations of the shell structure. The calculated results of the natural modes and frequencies of a model disk are compared with the experimental results with good quantitative agreement. .

Topics: AERODYNAMIC FORCES, ALGORITHMS, MATHEMATICAL MODELS, REGRESSION ANALYSIS, STABILITY DERIVATIVES,...

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Jul 25, 2010
07/10

by
NON

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A common recommendation is established for the implementation of a spacecraft telecommand data routing service by the agencies participating in the CCSDS. The operating principles and procedures for the CCSDS are defined in a reference. The context of the data routing service within the overall telecommand system is described in another reference. This recommendation addresses the procedures and data unit formats implemented within the segmentation layer and the transfer layer of the...

Topics: ALGORITHMS, COMPUTER NETWORKS, REFINING, BANDWIDTH, GRID GENERATION (MATHEMATICS), MATRICES...

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367

Jul 11, 2010
07/10

by
NON

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The total matrix of alternate Spacelab processing concepts and the rejection rationale utilized to reduce the matrix of 243 alternates to the final candidate processing concepts are developed. The work breakdown structure used for the systematic estimation and compilation of integration and checkout resources is presented along with descriptors of each element. Program models are provided of the space transportation system, the Spacelab, the orbiter, and the ATL that were used as the basis for...

Topics: FREE ATMOSPHERE, GRAVIMETRY, GRAVITY ANOMALIES, BLOCK DIAGRAMS, COVARIANCE, DATA ACQUISITION,...

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363

May 23, 2011
05/11

by
Rybicki, George C

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A Deep Level Transient Spectroscopy (DLTS) study of native and radiation induced defects in MOCVD n on p 6H-SiC diodes has been conducted. Three majority carrier levels were found, at E(sub v) 0.50 eV, E(sub v)0.55 eV and E(sub v)0.69 eV, and three minority carrier deep levels were found, at E(sub c)-0.38 eV, E(sub c)-0.48 eV and E(sub c)-0.58 eV. These 6 levels were initally observed in the unirradiated materials. Their concentration increased 2 to 13 fold after irradiation to a fluence of 2 x...

Topics: TRACKING (POSITION), APPROXIMATION, DIFFERENTIAL EQUATIONS, HELICOPTER CONTROL, MATRICES...

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358

May 31, 2011
05/11

by
NON

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This document presents the full-scale analyses of the CFD RSRM. The RSRM model was developed with a 20 second burn time. The following are presented as part of the full-scale analyses: (1) RSRM embedded inclusion analysis; (2) RSRM igniter nozzle design analysis; (3) Nozzle Joint 4 erosion anomaly; (4) RSRM full motor port slag accumulation analysis; (5) RSRM motor analysis of two-phase flow in the aft segment/submerged nozzle region; (6) Completion of 3-D Analysis of the hot air nozzle...

Topics: AUTOMATIC CONTROL, LINEAR QUADRATIC REGULATOR, AUTONOMY, FEEDBACK CONTROL, GRAVITATIONAL EFFECTS,...

347
347

May 23, 2011
05/11

by
Choi, Sung R.; Salem, Jonathan A.; Holland, Frederic A

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The two estimation methods, individual data and arithmetic mean methods, were used to determine the slow crack growth (SCG) parameters (n and D) of advanced ceramics and glass from a large number of room- and elevated-temperature constant stress-rate ('dynamic fatigue') test data. For ceramic materials with Weibull modulus greater than 10, the difference in the SCG parameters between the two estimation methods was negligible; whereas, for glass specimens exhibiting Weibull modulus of about 3,...

Topics: COMPUTATIONAL GRIDS, MULTIPROCESSING (COMPUTERS), HEURISTIC METHODS, MATRICES (MATHEMATICS),...

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345

May 23, 2011
05/11

by
Babcock, Dale A.; Bruce, Robert A

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The advantages of high-molecular-weight gas (heavy gas) as a wind-tunnel medium have been recognized for some time. The current heavy gas of choice chlorofluorocarbon-12(CFC-12) (refrigerant R12) for the Transonic Dynamics Tunnel(TDT) must be replaced because manufacture of this gas ceased in 1995. An attractive replacement is 1,1,1,2-tetrafluoroethane (refrigerant R134a). Acceptable properties of this gas include molecular weight and speed of sound. Its vapor pressure allows simplified...

Topics: ALGORITHMS, ROBOT ARMS, DEGREES OF FREEDOM, WEIGHTING FUNCTIONS, MATRICES (MATHEMATICS), LEAST...

Computationally feasible solutions are studied for a number of problems related to a M/M/1 queve in which the arrival and service rates vary according to the state of an underlying Markov chain. Our results may be used to mode the effects of rush-hour phenomena or other extraneous fluctuations on the characteristics of an M/M/1 queue.

Topics: DTIC Archive, Neuts,Marcel F, DELAWARE UNIV NEWARK DEPT OF STATISTICS AND COMPUTER SCIENCE,...

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339

Jul 11, 2010
07/10

by
Ahrons, R. W

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An increase in efficiency from 2% to over 7% was achieved by a solar cell that used polycrystal silicon heterojunction with SnO2 glass. For Single crystal substrates, efficiencies close to 10% were measured. These cells had the same structures as polycrystalline cells. Work on p/n heterojunction using In2O3 glass resulted in cells of 3% efficiency on polycrystalline material and 4% efficiency on single crystal material.

Topics: COMPUTERIZED SIMULATION, DYNAMIC STRUCTURAL ANALYSIS, PROBLEM SOLVING, RIGID STRUCTURES,...

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334

May 22, 2011
05/11

by
Hyatt, Mark J.; Bansal, Narottam P

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Crystallization kinetics of BaO.Al2O3.2SiO2 (BAS) and SrO.Al2O3.2SiO2 (SAS) glasses in bulk and powder forms have been studied by non-isothermal differential scanning calorimetry (DSC). The crystal growth activation energies were evaluated to be 473 and 451 kJ/mol for bulk samples and 560 and 534 kJ/mol for powder specimens in BAS and SAS glasses, respectively. Development of crystalline phases on thermal treatments of glasses at various temperatures has been followed by powder x-ray...

Topics: ALGORITHMS, CHOLESKY FACTORIZATION, DATA STRUCTURES, MATRICES (MATHEMATICS), COMPUTATION, MEMORY...

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332

May 30, 2011
05/11

by
Comiso, Josefino C

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Co-registered and continuous satellite data of sea ice concentrations and surface ice temperatures from 1981 to 1999 are analyzed to evaluate relationships between these two critical climate parameters and what they reveal in tandem about the changing Arctic environment. During the 18-year period, the actual Arctic ice area is shown to be declining at a rate of 3.1 /- 0.4 % /decade while the surface ice temperature has been increasing at 0.4 /- 0.2 K /decade. Yearly anomaly maps also show that...

Topics: COMPUTATIONAL GRIDS, POLARIZERS, MAXWELL EQUATION, BEAMS (RADIATION), MATHEMATICAL MODELS,...

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Jun 21, 2010
06/10

by
Hunter, W. W., Jr

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Laboratory measurements of rotational temperatures in static low density air with electron beam probe

Topics: LINEARITY, OPTIMAL CONTROL, TRAJECTORY OPTIMIZATION, CONSTRAINTS, HAMILTONIAN FUNCTIONS, LINEAR...

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Jul 25, 2010
07/10

by
Flynn, Michael J.; Kanerva, Pentti; Ahanin, Bahram; Bhadkamkar, Neal; Flaherty, Paul; Hickey, Phili

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Sparse distributed memory is a generalized random access memory (RAM) for long binary words. Such words can be written into and read from the memory, and they can be used to address the memory. The main attribute of the memory is sensitivity to similarity, meaning that a word can be read back not only by giving the original right address but also by giving one close to it as measured by the Hamming distance between addresses. Large memories of this kind are expected to have wide use in speech...

Topics: EARTH-MOON TRAJECTORIES, LUNAR ORBITS, MATRICES (MATHEMATICS), MIDCOURSE GUIDANCE, ORBITAL...

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May 23, 2011
05/11

by
Long, Christopher C.; Horan, Stephe

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A concept for the addition of a Demand Assignment Multiple Access (DAMA) service to NASA's current Space Network (SN) is developed. Specifically, the design of a receiver for the DAMA channel is outlined. Also, an outline of the procedures taken to process the received service request is presented. The modifications to the (SN) system are minimal. The post reception processing is accomplished using standard commercial off the shelf (COTS) packages. The result is a random access system capable...

Topics: CODING, ALGEBRA, MATRICES (MATHEMATICS), PARITY, LINEAR EQUATIONS, THEOREMS, GEOMETRY

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Jun 1, 2011
06/11

by
Brown, W. Byron; Monroe, William R

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A theoretical analysis of the temperature distribution through the trailing portion of a blade near the coolant passages of liquid cooled gas turbines was made. The analysis was applied to obtain the hot spot temperatures at the trailing edge and influence of design variables. The effective gas temperature was varied from 2000 degrees to 5000 degrees F in each investigation.

Topics: NAVIER-STOKES EQUATION, VISCOUS FLUIDS, FRICTION, STRESS ANALYSIS, SHEAR FLOW, ONE DIMENSIONAL...