Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Mathematical programming”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 865 records · Page 48
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Using Virtual and In-Person Engagement Opportunities to Connect K-12 Students, Teachers, and the Public With NASA Astromaterials Research and Exploration Science Assets

Engaging K-12 students, teachers, and the public with NASA Astromaterials Research and Exploration Science (ARES) assets provides an extraordinary opportunity to connect audiences with authentic aspects unique to our nation's space program. NASA ARES has effectively engaged audiences with 1) Science, Technology, Engineering and Mathematics (STEM) experts, 2) NASA specialized facilities, and 3) NASA astromaterial samples through both virtual and in-person engagement opportunities. These engagement opportunities help connect local and national audiences with STEM role models, promote the exciting work being facilitated through NASA's Science Mission Directorate, and expose our next generation of scientific explorers to science they may be inspired to pursue as a future STEM career.

Graff, P.↗
NASA NTRS2005

Program Computes Sound Pressures at Rocket Launches

Launch Vehicle External Sound Pressure is a computer program that predicts the ignition overpressure and the acoustic pressure on the surfaces and in the vicinity of a rocket and launch pad during launch. The program generates a graphical user interface (GUI) that gathers input data from the user. These data include the critical dimensions of the rocket and of any launch-pad structures that may act as acoustic reflectors, the size and shape of the exhaust duct or flame deflector, and geometrical and operational parameters of the rocket engine. For the ignition-overpressure calculations, histories of the chamber pressure and mass flow rate also are required. Once the GUI has gathered the input data, it feeds them to ignition-overpressure and launch-acoustics routines, which are based on several approximate mathematical models of distributed sources, transmission, and reflection of acoustic waves. The output of the program includes ignition overpressures and acoustic pressures at specified locations.

Ogg, Gary↗
NASA NTRS1972

Numerical method and FORTRAN program for the solution of an axisymmetric electrostatic collector design problem

The numerical calculation is described of the steady-state flow of electrons in an axisymmetric, spherical, electrostatic collector for a range of boundary conditions. The trajectory equations of motion are solved alternately with Poisson's equation for the potential field until convergence is achieved. A direct (noniterative) numerical technique is used to obtain the solution to Poisson's equation. Space charge effects are included for initial current densities as large as 100 A/sq cm. Ways of dealing successfully with the difficulties associated with these high densities are discussed. A description of the mathematical model, a discussion of numerical techniques, results from two typical runs, and the FORTRAN computer program are included.

Reese, O. W.↗
NASA NTRS1987

Meteor velocity distribution and an optimum monitoring mathematical model

At present, there are a great number of radio meteor, ionosphere and rocket observation data for the altitude range of 80 to 100 km which indicate the existence of large scale circulation systems in the mesopause to low thermosphere range which change regularly with season and latitude. But the existing observation network and observation programs are not optimal for revealing the main factors forming the circulation mode at these altitudes. A generalized optimum monitoring mathematical model is offered for consideration. The model input data are distribution density, response function, individual measurement root mean square uncertainty and detection effectiveness function. The model makes it possible to obtain the observation distribution density, the minimal possible dispersion and optimized system effectiveness.

Volkov, N. G.↗
NASA NTRS1983

Statistical correlation of structural mode shapes from test measurements and NASTRAN analytical values

The software and procedures of a system of programs used to generate a report of the statistical correlation between NASTRAN modal analysis results and physical tests results from modal surveys are described. Topics discussed include: a mathematical description of statistical correlation, a user's guide for generating a statistical correlation report, a programmer's guide describing the organization and functions of individual programs leading to a statistical correlation report, and a set of examples including complete listings of programs, and input and output data.

Purves, L.↗
NASA NTRS1990

Software Model Of Software-Development Process

Collection of computer programs constitutes software tool for simulation of medium- to large-scale software-development projects. Necessary to include easily identifiable and more-readily quantifiable characteristics like costs, times, and numbers of errors. Mathematical model incorporating these and other factors of dynamics of software-development process implemented in the Software Life Cycle Simulator (SLICS) computer program. Simulates dynamics of software-development process. In combination with input and output expert software systems and knowledge-based management software system, develops information for use in managing large software-development project. Intended to aid managers in planning, managing, and controlling software-development processes by reducing uncertainties in budgets, required personnel, and schedules.

Lin, Chi Y.↗
NASA NTRS1983

Development of the functional simulator for the Galileo attitude and articulation control system

A simulation program for verifying and checking the performance of the Galileo Spacecraft's Attitude and Articulation Control Subsystem's (AACS) flight software is discussed. The program, which is called Functional Simulator (FUNSIM), provides a simple method of interfacing user-supplied mathematical models coded in FORTRAN which describes spacecraft dynamics, sensors, and actuators; this is done with the AACS flight software, coded in HAL/S (High-level Advanced Language/Shuttle). It is thus able to simulate the AACS flight software accurately to the HAL/S statement level in the environment of a mainframe computer system. FUNSIM also has a command and data subsystem (CDS) simulator. It is noted that the input/output data and timing are simulated with the same precision as the flight microprocessor. FUNSIM uses a variable stepsize numerical integration algorithm complete with individual error bound control on the state variable to solve the equations of motion. The program has been designed to provide both line printer and matrix dot plotting of the variables requested in the run section and to provide error diagnostics.

Namiri, M. K.↗
NASA NTRS1972

Computer program draws three-dimensional surfaces

Computer plotting program PLOT 3D draws views of surface forms z = f(x,y). Surface thus defined by program may be drawn after arbitrary rotations. Program portrays behavior of various functions involving two variables in many engineering, physics, and mathematical relationships.

Canright, R. B., Jr.↗
NASA NTRS1972

New considerations for pogo prevention on space shuttle

Recommendations for improving the methodology of pogo suppression for the space shuttle include: Consideration of inter-pump location for accumulator or active device, inclusion of tank outflow effects in dynamic structural analysis, the use of simplified transfer functions in systems studies, three phase dynamic testing program for turbopump with development of dynamic flowmeters, and the use of a linearized mathematical model for engine physics studies.

Rubin, S.↗
NASA NTRS1973

Apollo experience report: The development of design-loads criteria, methods, and operational procedures for prelaunch, lift-off, and midboost conditions

The prelaunch, lift-off, and midboost conditions that are important to the design of spacecraft are described. Original Apollo design concepts that were deficient in realistic and accurate analysis of spacecraft structural loads in a wind environment also are included. Important improvements in design criteria, mathematical models, wind-monitoring procedures, and loads analyses are discussed. Recommendations for future programs are presented.

Mackey, A. C.↗
NASA NTRS1980

Discrete Tchebycheff orthonormal polynomials and applications

Discrete Tchebycheff orthonormal polynomials offer a convenient way to make least squares polynomial fits of uniformly spaced discrete data. Computer programs to do so are simple and fast, and appear to be less affected by computer roundoff error, for the higher order fits, than conventional least squares programs. They are useful for any application of polynomial least squares fits: approximation of mathematical functions, noise analysis of radar data, and real time smoothing of noisy data, to name a few.

Lear, W. M.↗
NASA NTRS1982

Eigenspace techniques for active flutter suppression

Mathematical models to be used in the control system design were developed. A computer program, which takes aerodynamic and structural data for the ARW-2 aircraft and converts these data into state space models suitable for use in modern control synthesis procedures, was developed. Reduced order models of inboard and outboard control surface actuator dynamics and a second order vertical wind gust model were developed. An analysis of the rigid body motion of the ARW-2 was conducted. The deletion of the aerodynamic lag states in the rigid body modes resulted in more accurate values for the eigenvalues associated with the plunge and pitch modes than were obtainable if the lag states were retained.

Garrard, W. L.↗
NASA NTRS1985

Theoretical Investigation Of Dielectric Horn Antennas

Mathematical model applicable to both solid and hollow dielectric horn antennas implemented in computer program. Conventional hollow metal horns have several disadvantages: difficult to fabricate at short wavelenghts and conducting properties of metal tend to deteriorate with increasing frequency. Dielectric horns offer advantages over conventional metal horns. Computer program permits user to investigate potential of various dielectricantenna designs.

Raines, J. K.↗
NASA NTRS1988

Visibility of the lunar crescent

A model designed to predict whether or not the moon will be visible under any set of observing conditions is presented. It explicitly includes atmospheric clarity, which is calculated from the site's altitude, latitude, temperature, relative humidity, aerosol content, and time of the year. This mathematical model is combined with a lunar and solar ephemeris to yield a computer program which will predict the date of the first crescent sighting from any location. A list of 201 observations of lunar visibility was collected to test this model and other models. It is found that criteria involving the moonset lagtime and the moon's age have zones of uncertainty which typically cover the entire earth.

Schaefer, Bradley E.↗
NASA NTRS1990

Characterization Of Robot Work Cell

Iterative process of measurement and computation used to characterize work cell of robot, increasing accuracy of mathematical model of work cell. Characterization needed because model used in off-line programming (OLP) to compute paths to control motion of robot. Increases accuracies of model and paths.

Anderson, Ronald R.↗