Power flow studies provide a systematic mathematical approach for determination of various bus voltages, there phase angle, active and reactive power flows through different branches, generators and loads under steady state condition. In this paper, the purpose of power flow analysis is to determine four bus system power flows. Case studies have been performed on Lawpita Taungoo Kamarnat Hlawga 230kV Line Myanmar. This paper presents a reliable method to meet the requirements by developing a...

Topics: Electronics & Communication Engineering, Load Flow, Newton-Raphson Method, MATLAB, Shunt...

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177

Jun 9, 2011
06/11

by
Butler, Ricky W.; Caldwell, James L.; DiVito, Ben L

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This paper presents a high-level design for a reliable computing platform for real-time control applications. The design tradeoffs and analyses related to the development of a formally verified reliable computing platform are discussed. The design strategy advocated in this paper requires the use of techniques that can be completely characterized mathematically as opposed to more powerful or more flexible algorithms whose performance properties can only be analyzed by simulation and testing....

Topics: NEWTON-RAPHSON METHOD, UNSTRUCTURED GRIDS (MATHEMATICS), GRID GENERATION (MATHEMATICS), STRUCTURED...

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Space simulation - conference

Topics: BALL BEARINGS, CENTRIFUGAL FORCE, THRUST LOADS, FATIGUE LIFE, MATHEMATICAL MODELS, NEWTON-RAPHSON...

180
180

Jun 27, 2010
06/10

by
Glassey, E. A

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Mechanical function generators with potentiometer as sensing element

Topics: COMPUTER PROGRAMS, LAGRANGE MULTIPLIERS, NEWTON-RAPHSON METHOD, POWER SERIES, TRAJECTORY...

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56

May 5, 2016
05/16

by
IJOER Engineering journal

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Computational techniques are proposed for a numerical solution of an inverse problem that arises in a study of a microbial depolymerization processes. The Newton-Raphson method in conjunction with the Newton’s method is applied to a time factor that involves three parameters. The Newton-Raphson method reduces a system of three equations for three unknowns to a single variable equation, which is solved with the Newton’s method. Those techniques were applied to a microbial...

Topics: Newton’s method, Newton-Raphson method, biodegradation, polymer, mathematical model, numerical...

409
409

May 27, 2011
05/11

by
Hall, Charles E.; Gallaher, Michael W.; Hendrix, Neal D

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The Vehicle Control Systems Team at Marshall Space Flight Center, Systems Dynamics Laboratory, Guidance and Control Systems Division is designing under a cooperative agreement with Lockheed Martin Skunkworks, the Ascent, Transition, and Entry flight attitude control system for the X-33 experimental vehicle. Ascent flight control begins at liftoff and ends at linear aerospike main engine cutoff (NECO) while Transition and Entry flight control begins at MECO and concludes at the terminal area...

Topics: DESIGN ANALYSIS, OPTIMIZATION, NAVIER-STOKES EQUATION, COMPUTATIONAL FLUID DYNAMICS,...

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230

Jul 11, 2010
07/10

by
BOGACHEV, I. N.; DYAKOVA, M. A.; BEZRUKOVA, A. K.; SELITSKAYA, S. I

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DECOMPOSITION OF THE BETA-SOLID SOLUTION OCCURS AND DEFORMATION MARTENSITE IS FORMED IN TITANIUM ALLOYS WITH AN UNSTABLE BETA-SOLID SOLUTION AT NEGATIVE TEMPERATURES FROM -40 DEG TO -120 DEG. PRELIMINARY PLASTIC DEFORMATION BY EXPANSION (4%) AT NEGATIVE TEMPERATURES OF ALLOYS WITH AN UNSTABLE BETA-SOLID SOLUTION REDUCES THE INTENSITY OF DEFORMATION MARTENSITE AND CAUSES A SMALLER INCREASE OF STRENGTH PROPERTIES THAN COLD TREATMENT. SMALL PRELIMINARY PLASTIC DEFORMATION OF AN ALLOY WITH A MORE...

Topics: C-5 AIRCRAFT, FLOW DISTRIBUTION, NEWTON-RAPHSON METHOD, TURBULENT WAKES, VORTEX SHEETS, AERODYNAMIC...

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168

Jul 12, 2010
07/10

by
Dorsch, R. G.; Boyd, B

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No Abstract Available

Topics: ALGORITHMS, BUCKLING, EQUATIONS OF MOTION, KINETIC EQUATIONS, NONLINEAR EQUATIONS,...

Probability Collectives (PC) provides the information-theoretic extension of conventional full-rationality game theory to bounded rational games. Here an explicit solution to the equations giving the bounded rationality equilibrium of a game is presented. Then PC is used to investigate games in which the players use bounded rational best-response strategies. Next it is shown that in the continuum-time limit, bounded rational best response games result in a variant of the replicator dynamics of...

Topics: NASA Technical Reports Server (NTRS), INFORMATION THEORY, PROBABILITY THEORY, GAMES, DECISION...

Product Distribution (PD) theory is the information-theoretic extension of conventional full- rationality game theory to bounded rational games. Here PD theory is used to investigate games in which the players use bounded rational best-response strategies. This investigation illuminates how to determine the optimal organization chart for a corporation, or more generally how to order the sequence of moves of the players / employees so as to optimize an overall objective function. It is then...

Topics: NASA Technical Reports Server (NTRS), INFORMATION THEORY, GAME THEORY, PROBABILITY THEORY,...

A simple and efficient computational method is presented for unstructured surface grid generation. This method is built upon an advancing front technique combined with grid projection. The projection technique is based on a Newton-Raphson method. This combined approach has been successfully implemented for structured and unstructured grids. In this paper, the implementation for unstructured grid is discussed.

Topics: NASA Technical Reports Server (NTRS), NEWTON-RAPHSON METHOD, UNSTRUCTURED GRIDS (MATHEMATICS), GRID...

An iterative method is presented to solve the internal and external camera calibration parameters, given model target points and their images from one or more camera locations. The direct linear transform formulation was used to obtain a guess for the iterative method, and herein lies one of the strengths of the present method. In all test cases, the method converged to the correct solution. In general, an overdetermined system of nonlinear equations is solved in the least-squares sense. The...

Topics: NASA Technical Reports Server (NTRS), CCD CAMERAS, CALIBRATING, PHOTOGRAMMETRY, IMAGES, ITERATIVE...

A set of equations which transform position and angular orientation of the centroid of the payload platform of a six-degree-of-freedom motion simulator into extensions of the simulator's actuators has been derived and is based on a geometrical representation of the system. An iterative scheme, Newton-Raphson's method, has been successfully used in a real time environment in the calculation of the position and angular orientation of the centroid of the payload platform when the magnitude of the...

Topics: NASA Technical Reports Server (NTRS), MOTION, NEWTON-RAPHSON METHOD, REAL TIME OPERATION,...

Multilevel self-adaptive Newton-Raphson type strategies are developed to improve the solution efficiency of nonlinear finite element simulations of statically loaded structures. The overall strategy involves three basic levels. The first level involves preliminary solution tunneling via primative operators. Secondly, the solution is constantly monitored via quality/convergence/nonlinearity tests. Lastly, the third level involves self-adaptive algorithmic update procedures aimed at improving the...

Topics: NASA Technical Reports Server (NTRS), FINITE ELEMENT METHOD, MATHEMATICAL MODELS, NEWTON-RAPHSON...

476
476

Jul 12, 2010
07/10

by
Birks, N

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Sodium chloride is deposited on the surface of alumina substrates and exposed to air containing 1% SO2 at temperatures between 500 C and 700 C. In all cases the sodium chloride was converted to sodium sulfate. The volatilization of sodium chloride from the original salt particles was responsible for the development of a uniform coating of sodium sulfate on the alumina substrate. At temperatures above 625 C, a liquid NaCl-Na2SO4 autectic was formed on the substrate. The mechanisms for these...

Topics: SPACE RENDEZVOUS, TUMBLING MOTION, SPACECRAFT DOCKING, VIDEO EQUIPMENT, ANGULAR MOMENTUM, FIELD OF...

Groove parameters were determined to maximize the stability of herringbone grooved journal bearings. Parameters optimized were groove depth, width, length, and angle. Optimization was performed using a small eccentricity, infinite groove analysis in conjunction with: (1) a previously developed Newton-Raphson procedure for bearings with the smooth member rotating or with the grooved member rotating at low compressibility numbers, and (2) a newly-developed vector technique for bearings with the...

Topics: NASA Technical Reports Server (NTRS), DYNAMIC STABILITY, JOURNAL BEARINGS, COMPRESSIBILITY, FILM...

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59

May 20, 2017
05/17

by
Pedro J Matos

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In this thesis we start by reviewing theoretical aspects of micromagnetism. Since many technological applications only depend on the behavior of magnetization of ferromagnets with the applied magnetic field at a macroscopic scale, there is no need to use a highly detailed theory like quantum mechanics. Micromagnetics is the framework that captures at a mesoscopic level the essential dynamical behavior of a magnetization field. It describes the combination of a very fast processional motion and...

Topics: Micromagnetism, Landau-Lifshitz, Landau-Lifshitz-Gilbert, Rayleigh Dissipation, Implicit Midpoint...

A detailed description is presented of KEPLER, an IBM 360 computer program used for the solution of Kepler's equation for eccentric anomaly. The program KEPLER employs a second-order Newton-Raphson differential correction process, and it is faster than previously developed programs by an order of magnitude.

Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, KEPLER LAWS, ALGORITHMS, ECCENTRICITY, IBM...

The fabrication and testing of a pair of robot fingers designed to grasp two types of Orbital Replacement Unit (ORU) interfaces, the H Handle type and the Micro Square type are discussed. A closed-form solution is given for the force inverse kinematics. A numerical solution using the Newton-Raphson Method for force forward kinematics is given. Mathematical expressions are derived to compute forces/torques applied to the finger. Suggestions are given for improving finger fabrication. The results...

Topics: NASA Technical Reports Server (NTRS), CONNECTORS, END EFFECTORS, FINGERS, INVERSE KINEMATICS,...

The steady state displacements of a rotating advanced turboprop are computed using the geometrically nonlinear capabilities of COSMIC NASTRAN Rigid Format 4 and MSC NASTRAN Solution 64. A description of the modified Newton-Raphson algorithm used by Solution 64 and the iterative scheme used by Rigid Format 4 is provided. A representative advanced turboprop, SR3, was used for the study. Displacements for SR3 are computed for rotational speeds up to 10,000 rpm. The results show Solution 64 to be...

Topics: NASA Technical Reports Server (NTRS), DISPLACEMENT, NASTRAN, NONLINEAR SYSTEMS, PROPELLER BLADES,...

An algorithm for maximum likelihood (ML) estimation is developed primarily for multivariable dynamic systems. The algorithm relies on a new optimization method referred to as a modified Newton-Raphson with estimated sensitivities (MNRES). The method determines sensitivities by using slope information from local surface approximations of each output variable in parameter space. The fitted surface allows sensitivity information to be updated at each iteration with a significant reduction in...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, APPROXIMATION, MAXIMUM LIKELIHOOD ESTIMATES,...

Some of the methods of obtaining approximate numerical solutions to boundary value problems that arise in elastohydrodynamic lubrication are reviewed. The highlights of four general approaches (direct, inverse, quasi-inverse, and Newton-Raphson) are sketched. Advantages and disadvantages of these approaches are presented along with a flow chart showing some of the details of each. The basic question of numerical stability of the elastohydrodynamic lubrication solutions, especially in the...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY VALUE PROBLEMS, ELASTOHYDRODYNAMICS, LUBRICATION,...

The objective initially proposed was to analyze shuttle remote manipulator (SRM) performance data collected during a Shuttle Flight. The data was to consist of video TRAC data collected via a video recorder. Unfortunately, the flight never collected the data due to higher priority experiments superseding it. As a result, the research team at Texas A&M was directed to work on several other pressing issues regarding the TRAC sensor. All but one of these issues were reported earlier in the...

Topics: NASA Technical Reports Server (NTRS), IMAGE ANALYSIS, NEWTON-RAPHSON METHOD, REMOTE SENSORS,...

Four, linear, exponential, integration algorithms (two implicit, one explicit, and one predictor/corrector) are applied to a viscoplastic model to assess their capabilities. Viscoplasticity comprises a system of coupled, nonlinear, stiff, first order, ordinary differential equations which are a challenge to integrate by any means. Two of the algorithms (the predictor/corrector and one of the implicits) give outstanding results, even for very large time steps.

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, DIFFERENTIAL EQUATIONS, NONLINEARITY, NUMERICAL...

A method and apparatus for analyzing steady state and transient flow in a complex fluid network, modeling phase changes, compressibility, mixture thermodynamics, external body forces such as gravity and centrifugal force and conjugate heat transfer. In some embodiments, a graphical user interface provides for the interactive development of a fluid network simulation having nodes and branches. In some embodiments, mass, energy, and specific conservation equations are solved at the nodes, and...

Topics: NASA Technical Reports Server (NTRS), EQUILIBRIUM FLOW, THERMODYNAMICS, THERMOPHYSICAL PROPERTIES,...

The coordinate independence of gravitational radiation and the parameterized post-Newtonian approximation from which it is extended are described. The general consistency of the field equations with Bianchi identities, gauge conditions, and the Newtonian limit of the perfect fluid equations of hydrodynamics are studied. A technique of modification is indicated for application to vector-metric or double metric theories, as well as to scalar-tensor theories.

Topics: NASA Technical Reports Server (NTRS), ASTROPHYSICS, GRAVITATIONAL FIELDS, NEWTON-RAPHSON METHOD,...

The sensitivities of the convergence characteristics of the methods to initially assumed parameters and trial solution, convergence times, computer logic, and storage requirements are discussed. Numerical comparison of the convergence characteristics is made by considering a minimum time, low thrust, Earth-Mars transfer trajectory. A modified quasi-linearization method reduces convergence time by approximately 70% when compared with the generalized Newton-Raphson method and allows the terminal...

Topics: NASA Technical Reports Server (NTRS), NEWTON-RAPHSON METHOD, PERTURBATION, SPACECRAFT TRAJECTORIES,...

Performance prediction of turbomachines is a significant part of aircraft propulsion design. In the conceptual design stage, there is an important need to quantify compressor and turbine aerodynamic performance and develop initial geometry parameters at the 2-D level prior to more extensive Computational Fluid Dynamics (CFD) analyses. The Object-oriented Turbomachinery Analysis Code (OTAC) is being developed to perform 2-D meridional flowthrough analysis of turbomachines using an implicit...

Topics: NASA Technical Reports Server (NTRS), OBJECT-ORIENTED PROGRAMMING, TURBOMACHINERY, AERODYNAMIC...

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181

Jul 12, 2010
07/10

by
Schairer, E. T.; Mendoza, J. P

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Adaptive wall wind tunnel research is summarized. Small scale two and three dimensional wind tunnel experiments and numerical experiments with a three dimensional adaptive wall simulator are included. A NACA 0012 airfoil was tested in a 25 by 13 cm slotted wall test section. Airflow through the test section walls was controlled by adjusting the pressures in segmented plenums. Interference free conditions were successfully attained in subsonic and transonic flows. For the three dimensional...

Topics: ALGORITHMS, PLOTTING, STEADY STATE, THERMAL CONDUCTIVITY, TRANSIENT HEATING, COMPUTER PROGRAMS,...

A summary is given of strategies which enable the automatic adjustment of the constraint surfaces recently used to extend the range and numerical stability/efficiency of nonlinear finite element equation solvers. In addition to handling kinematic and material induced nonlinearity, both pre-and postbuckling behavior can be treated. The scheme employs localized bounds on various hierarchical partitions of the field variables. These are used to resize, shape, and orient the global constraint...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, BUCKLING, FINITE ELEMENT METHOD, KINEMATICS,...

A brief study was made to assess the applicability of the Newton-Raphson digital computer program as a routine technique for extracting aerodynamic derivatives from flight tests of lifting body types of vehicles. Lateral-direction flight data from flight tests of the HL-10 lifting body reserch vehicle were utilized. The results in general, show the computer program to be a reliable and expedient means for extracting derivatives for this class of vehicles as a standard procedure. This result was...

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC STABILITY, HL-10 REENTRY VEHICLE, NEWTON-RAPHSON...

A FORTRAN program is offered which computes a maximum likelihood estimate of the parameters of any linear, constant coefficient, state space model. For the case considered, the maximum likelihood estimate can be identical to that which minimizes simultaneously the weighted mean square difference between the computed and measured response of a system and the weighted square of the difference between the estimated and a priori parameter values. A modified Newton-Raphson or quasilinearization...

Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, LINEAR SYSTEMS, MATHEMATICAL MODELS,...

A method for reliably extracting real zeros of real polynomials using an expanded two-point secant and bisection method is formed into an algorithm for a digital computer, and a computer program based on this algorithm is presented. The results obtained with the program show that the proposed method compares favorably with the Laguerre, Newton-Raphson, and Jenkins-Traub methods when the polynomial has all real zeros, and is more efficient when the polynomial has complex zeros.

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTER PROGRAMS, POLYNOMIALS, REAL NUMBERS,...

The report documents the recent effort to enhance a transient linear heat transfer code so as to solve nonlinear problems. The linear heat transfer code was originally developed by Dr. Kim Bey of NASA Largely and called the Structure-Compatible Heat Transfer (SCHT) code. The report includes four parts. The first part outlines the formulation of the heat transfer problem of concern. The second and the third parts give detailed procedures to construct the nonlinear finite element equations and...

Topics: NASA Technical Reports Server (NTRS), NONLINEAR EQUATIONS, FINITE ELEMENT METHOD, HEAT TRANSFER,...

Performance prediction of turbomachines is a significant part of aircraft propulsion design. In the conceptual design stage, there is an important need to quantify compressor and turbine aerodynamic performance and develop initial geometry parameters at the 2-D level prior to more extensive Computational Fluid Dynamics (CFD) analyses. The Object-oriented Turbomachinery Analysis Code (OTAC) is being developed to perform 2-D meridional flowthrough analysis of turbomachines using an implicit...

Topics: NASA Technical Reports Server (NTRS), TURBOMACHINERY, COMPUTATIONAL FLUID DYNAMICS, OBJECT-ORIENTED...

A multiphase selfadaptive predictor corrector type algorithm was developed. This algorithm enables the solution of highly nonlinear structural responses including kinematic, kinetic and material effects as well as pro/post buckling behavior. The strategy involves three main phases: (1) the use of a warpable hyperelliptic constraint surface which serves to upperbound dependent iterate excursions during successive incremental Newton Ramphson (INR) type iterations; (20 uses an energy constraint to...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, BUCKLING, EQUATIONS OF MOTION, KINETIC EQUATIONS,...

There are three things required for evapotranspiration to occur: (1) energy (580 cal/gm) for the change of phase of the water; (2) a source of the water, i.e., adequate soil moisture in the surface layer or in the root zone of the plant; and (3) a sink for the water, i.e., a moisture deficit in the air above the ground. Remote sensing can contribute information to the first two of these conditions by providing estimates of solar insolation, surface albedo, surface temperature, vegetation cover,...

Topics: NASA Technical Reports Server (NTRS), EVAPOTRANSPIRATION, INSOLATION, SOIL MOISTURE, SURFACE...

A two-parameter class of time-stepping algorithms for nonlinear structural dynamics is investigated. What sets the present method apart from other concurrent algorithms is the fact that it can be used to some advantage in sequential machines as well. Thus, substantial speed-ups are obtained on a single processor as the number of subdomains is increased. An additional O(p) speed-up is obtained when p processors are utilized. The test case discussed is being repeated for a mesh comprising four...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, ASYMPTOTIC SERIES, DYNAMIC STRUCTURAL ANALYSIS,...

An efficient implementation of Generalized Predictive Control using a multi-layer feedforward neural network as the plant's nonlinear model is presented. In using Newton-Raphson as the optimization algorithm, the number of iterations needed for convergence is significantly reduced from other techniques. The main cost of the Newton-Raphson algorithm is in the calculation of the Hessian, but even with this overhead the low iteration numbers make Newton-Raphson faster than other techniques and a...

Topics: NASA Technical Reports Server (NTRS), FEEDFORWARD CONTROL, NEURAL NETS, NEWTON-RAPHSON METHOD,...

A computer program implements a thermal model of an insulated wire carrying electric current and surrounded by a vacuum. The model includes the effects of Joule heating, conduction of heat along the wire, and radiation of heat from the outer surface of the insulation on the wire. The model takes account of the temperature dependences of the thermal and electrical properties of the wire, the emissivity of the insulation, and the possibility that not only can temperature vary along the wire but,...

Topics: NASA Technical Reports Server (NTRS), COMPUTER PROGRAMS, ELECTRIC CURRENT, TEMPERATURE EFFECTS,...

An important part of building high fidelity mathematical models based on measured data is calculating the accuracy associated with statistical estimates of the model parameters. Indeed, without some idea of the accuracy of parameter estimates, the estimates themselves have limited value. In this work, an expression based on theoretical analysis was developed to properly compute parameter accuracy measures for maximum likelihood estimates with colored residuals. This result is important because...

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT STABILITY, DYNAMIC CHARACTERISTICS, MATHEMATICAL...

This paper describes a finite volume computational thermo-fluid dynamics method to solve for Navier-Stokes equations in conjunction with energy equation and thermodynamic equation of state in an unstructured coordinate system. The system of equations have been solved by a simultaneous Newton-Raphson method and compared with several benchmark solutions. Excellent agreements have been obtained in each case and the method has been found to be significantly faster than conventional Computational...

Topics: NASA Technical Reports Server (NTRS), DESIGN ANALYSIS, OPTIMIZATION, NAVIER-STOKES EQUATION,...

A new approach for global path planning of redundant manipulators is proposed. It poses the path planning problem as a finite time nonlinear control problem. The solution is found by a Newton-Raphson type algorithm. This technique is capable of handling various goal task descriptions as well as incorporating both joint and task space constraints. The algorithm has shown promising preliminary results in planning joint path sequences for 3R and 4R planar robots to meet Cartesian tip tracking and...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, MANIPULATORS, NEWTON-RAPHSON METHOD,...

A modified Newton-Raphson or quasilinearization minimization technique for determining stability derivatives from flight data was developed and compared with simple-equations, analog-matching, least-squares, and Shinbrot methods of analysis. For the data analyzed, the solutions computed by using the estimates obtained from the Newton-Raphson technique fit the data and determined coefficients adequately. A further modification to include a priori information was found to be useful. A model...

Topics: NASA Technical Reports Server (NTRS), AIRCRAFT CONTROL, AIRCRAFT STABILITY, FLIGHT TESTS,...

The approach used to assess shadowing reductions on the heating of orbiting trusses involves determining the heating rates with slender member shadowing effects included and then obtaining the thermal response of the shadowed member. Steps taken to identify shadowers, find locations where shadowing occurs and calculate shadow intensity are listed. The finite element thermal structural analysis of cable stiffened space structure is delineated and the exact solution of the caternary problem is...

Topics: NASA Technical Reports Server (NTRS), DYNAMIC RESPONSE, LARGE SPACE STRUCTURES, SHADOWS, STRUCTURAL...

A first-order thrust load analysis that considers centrifugal forces but which neglects gyroscopics, elastohydrodynamics, and thermal effects was performed. The analysis was applied to a 150-mm-bore angular-contact ball bearing. Fatigue life, contact loads, and contact angles are shown for conventional and arched bearings. The results indicate that an arched bearing is highly desirable for high-speed applications. In particular, at an applied load of 4448 n (1000 lb) and a DN value of 3 million...

Topics: NASA Technical Reports Server (NTRS), BALL BEARINGS, CENTRIFUGAL FORCE, THRUST LOADS, FATIGUE LIFE,...

Equations are derived by using branched trajectory optimization techniques and the maximum principle to maximize the payload capability of a reusable tug/expendable kickstage vehicle configuration for planetary missions. The two stages and the payload are launched into a low earth orbit by a single space shuttle. The analysis includes correction for precession of the orbit. This correction is done by the tug. The tug propels the payload and the kickstage to an energy beyond earth escape and...

Topics: NASA Technical Reports Server (NTRS), EARTH ORBITAL RENDEZVOUS, EARTH ORBITS, ORBIT CALCULATION,...

NASA Glenn Research Center has been using an in house designed X25 based multi-source solar simulator since 2003. The simulator is set up for triple junction solar cells prior to measurements b y adjusting the three sources to produce the correct short circuit current, lsc, in each of three AM0 calibrated sub-cells. The past practice has been to adjust one source on one sub-cell at a time, iterating until all the sub-cells have the calibrated Isc. The new approach is to create a matrix of...

Topics: NASA Technical Reports Server (NTRS), SOLAR SIMULATORS, CALIBRATING, SOLAR CELLS, PHOTOVOLTAIC...

Recently Hall and Seddougui (1989) considered the secondary instability of large amplitude Goertler vortices in a growing boundary layer evolving into a three-dimensional flow with wavy vortex boundaries. They obtained a pair of coupled, linear ordinary differential equations for this instability which constituted an eigenproblem for the wavelength and frequency of this wavy mode. Investigations into the nonlinear version of this problem by Seddougui and Bassom have revealed several omissions...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYERS, FLOW STABILITY, THREE DIMENSIONAL FLOW, TIME...

Field-of-view limitations proved troublesome. Higher resolution was required. Side thrusters were too weak. The strategy logic was improved and the Kalman filter was augmented to estimate target attitude and tumble rate. Two separate filters were used. The new filter estimates target attitude and angular momentum. The Newton-Raphson iteration improves image interpretation.

Topics: NASA Technical Reports Server (NTRS), SPACE RENDEZVOUS, SPACECRAFT DOCKING, VIDEO EQUIPMENT,...