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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.

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NASA NTRS1992

Databases for LDEF results

One of the objectives of the team supporting the LDEF Systems and Materials Special Investigative Groups is to develop databases of experimental findings. These databases identify the hardware flown, summarize results and conclusions, and provide a system for acknowledging investigators, tracing sources of data, and future design suggestions. To date, databases covering the optical experiments, and thermal control materials (chromic acid anodized aluminum, silverized Teflon blankets, and paints) have been developed at Boeing. We used the Filemaker Pro software, the database manager for the Macintosh computer produced by the Claris Corporation. It is a flat, text-retrievable database that provides access to the data via an intuitive user interface, without tedious programming. Though this software is available only for the Macintosh computer at this time, copies of the databases can be saved to a format that is readable on a personal computer as well. Further, the data can be exported to more powerful relational databases, capabilities, and use of the LDEF databases and describe how to get copies of the database for your own research.

Bohnhoff-Hlavacek, Gail↗

DOE OSTI2013

Diagnosing heterogeneous dynamics in single-molecule/particle trajectories with multiscale wavelets

In this study, we describe a simple automated method to extract and quantify transient heterogeneous dynamical changes from large data sets generated in single-molecule/particle tracking experiments. Based on wavelet transform, the method transforms raw data to locally match dynamics of interest. This is accomplished using statistically adaptive universal thresholding, whose advantage is to avoid a single arbitrary threshold that might conceal individual variability across populations. How to implement this multiscale method is described, focusing on local confined diffusion separated by transient transport periods or hopping events, with three specific examples: in cell biology, biotechnology, and glassy colloid dynamics. The discussion is generalized within the framework of continuous time random walk. This computationally efficient method can run routinely on hundreds of millions of data points analyzed within an hour on a desktop personal computer.

36 MATERIALS SCIENCE↗

NASA NTRS1991

Approach and landing simulator for Space Shuttle Orbiter touchdown conditions

This study describes a computer simulation that provides an accurate calculation of the touchdown conditions. The program is small enough to operate on a personal computer. The program simulates the Orbiter trajectory from an altitude of 10,000 ft to the earth's surface. It assumes the Orbiter files close to its reference altitude profile, with negligible crosswind effects. Flight data have proven both assumption to be valid. By incorporating these assumptions with the Shuttle guidance logic, a quick approximation can be made of the touchdown speed and downrange distance to an accuracy within 400 ft of the mainframe prediction.

Walyus, Keith D.↗

NASA NTRS2000

Advances in Space Transportation Technology Toward the NASA Goals

NASA has set goals to increase safety by one hundred times while reducing cost tenfold over the next decade. This dramatic increase in safety will come by departing from a past emphasis on cost and performance to a new paradigm of safety and reliability, which, in turn, will drive down cost. To accomplish this, vehicle systems must be inherently reliable, functionally redundant wherever practical and designed to minimize or eliminate catastrophic failure modes. Over the next twenty-five years, NASA has set goals to increase safety ten thousand times while reducing cost one hundred fold. Safety will increase towards today's airline safety and the low price per flight has the potential to enable a 15-fold increase in the size of the current projected space launch market. This level of improvement is comparable to the developments in the 1970s in the computer microprocessor when microchips went from hundreds of thousands to tens of thousands of dollars - hailing the era of the personal computer. In order to achieve such ambitious cost goals, today's partial and fully expendable rockets must be replaced by fully reusable systems. A RLV can eliminate assembly and checkout of the large number of complex interfaces on today's Space Shuttle. Full reusability will eliminate the necessity to throw away expensive hardware and the need for on-going production. Systems in ten years will have to accommodate 50 to 100 missions per year and could be commercially certified for hundreds of flights. In twenty-five years, the number of flights per year could jump to over 1,000, which will require certification for thousands of flights. The large increase in flights per year will demand that current operations and maintenance procedures be revolutionized. Unlike the current shuttle, which requires several thousand personnel over five months to process, the next generation system must be turned around in one week with less than one hundred personnel. In contrast to the rigorous disassembly and inspections required for the Space Shuttle's subsystems, the next generation vehicle's on-board health monitoring systems will could tell the ground crews which systems need replacement before landing. In twenty-five years, vehicles will be re-flown within one with crews numbering less than one hundred. Fully automated ground processing systems must require only a handful of personnel to launch the vehicle. Due to the increased intelligence of on-board systems, only cursory walk-around inspections would be required between flights An assessment of the progress in breakthrough technologies toward these goals by the NASA Advanced Space Transportation Program is presented. These breakthrough technologies include combined rocket and air breathing propulsion, high strength lightweight structures, high temperature materials, vehicle health management, and flight operations.

Lyles, Garry M.↗

NASA NTRS1998

Finite Element and Plate Theory Modeling of Acoustic Emission Waveforms

A comparison was made between two approaches to predict acoustic emission waveforms in thin plates. A normal mode solution method for Mindlin plate theory was used to predict the response of the flexural plate mode to a point source, step-function load, applied on the plate surface. The second approach used a dynamic finite element method to model the problem using equations of motion based on exact linear elasticity. Calculations were made using properties for both isotropic (aluminum) and anisotropic (unidirectional graphite/epoxy composite) materials. For simulations of anisotropic plates, propagation along multiple directions was evaluated. In general, agreement between the two theoretical approaches was good. Discrepancies in the waveforms at longer times were caused by differences in reflections from the lateral plate boundaries. These differences resulted from the fact that the two methods used different boundary conditions. At shorter times in the signals, before reflections, the slight discrepancies in the waveforms were attributed to limitations of Mindlin plate theory, which is an approximate plate theory. The advantages of the finite element method are that it used the exact linear elasticity solutions, and that it can be used to model real source conditions and complicated, finite specimen geometries as well as thick plates. These advantages come at a cost of increased computational difficulty, requiring lengthy calculations on workstations or supercomputers. The Mindlin plate theory solutions, meanwhile, can be quickly generated on personal computers. Specimens with finite geometry can also be modeled. However, only limited simple geometries such as circular or rectangular plates can easily be accommodated with the normal mode solution technique. Likewise, very limited source configurations can be modeled and plate theory is applicable only to thin plates.

Prosser, W. H.↗

NASA NTRS2007

Driver Code for Adaptive Optics

A special-purpose computer code for a deformable-mirror adaptive-optics control system transmits pixel-registered control from (1) a personal computer running software that generates the control data to (2) a circuit board with 128 digital-to-analog converters (DACs) that generate voltages to drive the deformable-mirror actuators. This program reads control-voltage codes from a text file, then sends them, via the computer s parallel port, to a circuit board with four AD5535 (or equivalent) chips. Whereas a similar prior computer program was capable of transmitting data to only one chip at a time, this program can send data to four chips simultaneously. This program is in the form of C-language code that can be compiled and linked into an adaptive-optics software system. The program as supplied includes source code for integration into the adaptive-optics software, documentation, and a component that provides a demonstration of loading DAC codes from a text file. On a standard Windows desktop computer, the software can update 128 channels in 10 ms. On Real-Time Linux with a digital I/O card, the software can update 1024 channels (8 boards in parallel) every 8 ms.

Rao, Shanti↗

DOE OSTI2016

Automated metadata, provenance cataloging and navigable interfaces: ensuring the usefulness of extreme-scale data

The MPO (Metadata, Provenance, Ontology) Project successfully addressed the goal of improving the usefulness and traceability of scientific data by building a system that could capture and display all steps in the process of creating, analyzing and disseminating that data. Throughout history, scientists have generated handwritten logbooks to keep track of data, their hypotheses, assumptions, experimental setup, and computational processes as well as reflections on observations and issues encountered. Over the last several decades, with the growth of personal computers, handheld devices, and the World Wide Web, the handwritten logbook has begun to be replaced by electronic logbooks. This transition has brought increased capability such as supporting multi-media, hypertext, and fast searching. However, content creation and metadata (a set of data that describes and gives information about other data) capturing has for the most part remained a manual activity just as it was with handwritten logbooks. This has led to a fragmentation of data, processing, and annotation that has only accelerated as scientific workflows continue to increase in complexity. From a scientific perspective, it is very important to be able to understand the lineage of any piece of data: who, what, when, how, and why. This is typically referred to as data provenance. The fragmentation discussed previously often means that data provenance is lost. As scientific workflows move to powerful computers and become more complex, the ability to track all of the steps involved in creating a piece of data become even more difficult. It was the goal of the MPO (Metadata, Provenance, Ontology) Project to create a system (the MPO System) that allows for automatic provenance and metadata capturing in such a way to allow easy searching and browsing. This goal needed to be accomplished in a general way so that it may be used across a broad range of scientific domains, yet allow the addition of vocabulary (Ontology) that is domain specific as is required for intelligent searching and browsing in the scientific context. Through the creation and deployment of the MPO system, the goals of the project were achieved. An enhanced metadata, provenance, and ontology storage system was created. This was combined with innovative methodologies for navigating and exploring these data using a web browser for both experimental and simulation-based scientific research. In addition, a system to allow scientists to instrument their existing workflows for automatic metadata and provenance is part of the MPO system. In that way, a scientist can continue to use their existing methodology yet easily document their work. Workflows and data provenance can be displayed either graphically or in an electronic notebook format and support advanced search features including via ontology. The MPO system was successfully used in both Climate and Magnetic Fusion Energy Research. The software for the MPO system is located at https://github.com/MPO-Group/MPO and is open source distributed under the Revised BSD License. A demonstration site of the MPO system is open to the public and is available at https://mpo.psfc.mit.edu/. A Docker container release of the command line client is available for public download using the command docker pull jcwright/mpo-cli at https://hub.docker.com/r/jcwright/mpo-cli.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2024

via-wind (A Visual Impact Assessment Tool for Wind Turbines) [SWR-24-87]

Via-wind is an open-source tool for conducting visual impact assessments for wind turbines. It combines geographic information system (GIS) and 3D simulation methods to account for the key factors driving the visual impact of installed wind turbines, including distance, viewing angle, turbine orientation, visual exposure, and the cumulative effects of multiple turbines. This software is optimized for use in high-performance computing environments to enable large scale (e.g., country-wide) analysis, but can also be run on a single server or personal computer. For more information, please see the related journal article: https://www.sciencedirect.com/science/article/pii/S0306261924021846

Lopez, Anthony↗

NASA NTRS1991

Walking robot: A design project for undergraduate students

The objective of the University of Maryland walking robot project was to design, analyze, assemble, and test an intelligent, mobile, and terrain-adaptive system. The robot incorporates existing technologies in novel ways. The legs emulate the walking path of a human by an innovative modification of a crank-and-rocker mechanism. The body consists of two tripod frames connected by a turning mechanism. The two sets of three legs are mounted so as to allow the robot to walk with stability in its own footsteps. The computer uses a modular hardware design and distributed processing. Dual-port RAM is used to allow communication between a supervisory personal computer and seven microcontrollers. The microcontrollers provide low-level control for the motors and relieve the processing burden on the PC.

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NASA NTRS2006

PVM Enhancement for Beowulf Multiple-Processor Nodes

A recent version of the Parallel Virtual Machine (PVM) computer program has been enhanced to enable use of multiple processors in a single node of a Beowulf system (a cluster of personal computers that runs the Linux operating system). A previous version of PVM had been enhanced by addition of a software port, denoted BEOLIN, that enables the incorporation of a Beowulf system into a larger parallel processing system administered by PVM, as though the Beowulf system were a single computer in the larger system. BEOLIN spawns tasks on (that is, automatically assigns tasks to) individual nodes within the cluster. However, BEOLIN does not enable the use of multiple processors in a single node. The present enhancement adds support for a parameter in the PVM command line that enables the user to specify which Internet Protocol host address the code should use in communicating with other Beowulf nodes. This enhancement also provides for the case in which each node in a Beowulf system contains multiple processors. In this case, by making multiple references to a single node, the user can cause the software to spawn multiple tasks on the multiple processors in that node.

Springer, Paul↗

NASA NTRS2005

Data-Analysis System for Entry, Descent, and Landing

A report describes the Entry Descent Landing Data Analysis (EDA), which is a system of signal-processing software and computer hardware for acquiring status data conveyed by multiple-frequency-shift-keying tone signals transmitted by a spacecraft during descent to the surface of a remote planet. The design of the EDA meets the challenge of processing weak, fluctuating signals that are Doppler-shifted by amounts that are only partly predictable. The software supports both real-time and post processing. The software performs fast-Fourier-transform integration, parallel frequency tracking with prediction, and mapping of detected tones to specific events. The use of backtrack and refinement parallel-processing threads helps to minimize data gaps. The design affords flexibility to enable division of a descent track into segments, within each of which the EDA is configured optimally for processing in the face of signal conditions and uncertainties. A dynamic-lock-state feature enables the detection of signals using minimum required computing power less when signals are steadily detected, more when signals fluctuate. At present, the hardware comprises eight dual-processor personal-computer modules and a server. The hardware is modular, making it possible to increase computing power by adding computers.

Pham, Timothy↗

NASA NTRS1990

Computer Reader for the Blind

Optacon II uses the same basic technique of converting printed information into a tactile image as did Optacon. Optacon II can also be connected directly to a personal computer, which opens up a new range of job opportunities for the blind. Optacon II is not limited to reading printed words, it can convert any graphic image viewed by the camera. Optacon II demands extensive training for blind operators. TSI provides 60-hour training courses at its Mountain View headquarters and at training centers around the world. TeleSensory discontinued production of the Optacon as of December 1996.

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NASA NTRS1984

Optimum Cyclic Redundancy Codes for Noisier Channels

Binary cyclic redundancy codes for feedback communication over noisy digital links are considered. The standard 16 bit American Data and Computer Communication Protocol (ADCCP) polynomial is designed for digital links which already have a low input bit error probability. For file transfer between personal computers over telephone circuits, the quality of resulting digital circuit may be much lower. The 3 byte (24 bit) and 4 byte (32 bit) polynomials are considered. Generator polynomials of a certain class have minimum weight and yet achieve the bound on minimum distance for arbitrary codes. Particular choices for 24 bit and 32 bit redundancies are exhibited: of weight and distance 6 in the 24-bit case; and weight 10 and distance 8 in the 32-bit case.

Merkey, P.↗

NASA NTRS1984

Optimum cyclic redundancy codes for noisy channels

Merkey, P.↗

DOE OSTI2020

Performance Evaluation of Python Based Data Analytics Frameworks in Summit: Early Experiences

The explosion in the volumes of data generated from ever-larger simulation campaigns and experiments or observations necessitates competent tools for data wrangling and analysis). While the Oak Ridge Leadership Computing Facility (OLCF) provides a variety of tools to perform data wrangling and data analysis tasks, Python based tools often lack scalability, or the ability to fully exploit the computational capability of OLCF’s Summit supercomputer. NVIDIA RAPIDS and Dask offer a promising solution to accelerate and distribute data analytics workloads from personal computers to heterogeneous supercomputing systems. We discuss early performance evaluation results of RAPIDS and Dask on Summit to understand their capabilities, scalability, and limitations. Our evaluation includes a subset of RAPIDS libraries, i.e., cuDF, cuML, and cuGraph, and Chainer’s CuPy, and their multi-GPU variants when available.We also draw on the observed trends from the performance evaluation results to discuss best practices for maximizing performance.

Hernandez Arreguin, Benjamin↗

NASA NTRS1989

Stellar Inertial Navigation Workstation

Software and hardware assembled to support specific engineering activities. Stellar Inertial Navigation Workstation (SINW) is integrated computer workstation providing systems and engineering support functions for Space Shuttle guidance and navigation-system logistics, repair, and procurement activities. Consists of personal-computer hardware, packaged software, and custom software integrated together into user-friendly, menu-driven system. Designed to operate on IBM PC XT. Applied in business and industry to develop similar workstations.

Johnson, W.↗

NASA NTRS1998

The Data Acquisition and Control Systems of the Jet Noise Laboratory at the NASA Langley Research Center

The features of the data acquisition and control systems of the NASA Langley Research Center's Jet Noise Laboratory are presented. The Jet Noise Laboratory is a facility that simulates realistic mixed flow turbofan jet engine nozzle exhaust systems in simulated flight. The system is capable of acquiring data for a complete take-off assessment of noise and nozzle performance. This paper describes the development of an integrated system to control and measure the behavior of model jet nozzles featuring dual independent high pressure combusting air streams with wind tunnel flow. The acquisition and control system is capable of simultaneous measurement of forces, moments, static and dynamic model pressures and temperatures, and jet noise. The design concepts for the coordination of the control computers and multiple data acquisition computers and instruments are discussed. The control system design and implementation are explained, describing the features, equipment, and the experiences of using a primarily Personal Computer based system. Areas for future development are examined.

Jansen, B. J., Jr.↗

DOE OSTI2015

Deterministic absorbed dose estimation in computed tomography using a discrete ordinates method

Purpose: Organ dose estimation for a patient undergoing computed tomography (CT) scanning is very important. Although Monte Carlo methods are considered gold-standard in patient dose estimation, the computation time required is formidable for routine clinical calculations. Here, the authors instigate a deterministic method for estimating an absorbed dose more efficiently. Methods: Compared with current Monte Carlo methods, a more efficient approach to estimating the absorbed dose is to solve the linear Boltzmann equation numerically. In this study, an axial CT scan was modeled with a software package, Denovo, which solved the linear Boltzmann equation using the discrete ordinates method. The CT scanning configuration included 16 x-ray source positions, beam collimators, flat filters, and bowtie filters. The phantom was the standard 32 cm CT dose index (CTDI) phantom. Four different Denovo simulations were performed with different simulation parameters, including the number of quadrature sets and the order of Legendre polynomial expansions. A Monte Carlo simulation was also performed for benchmarking the Denovo simulations. A quantitative comparison was made of the simulation results obtained by the Denovo and the Monte Carlo methods. Results: The difference in the simulation results of the discrete ordinates method and those of the Monte Carlo methods was found to be small, with a root-mean-square difference of around 2.4%. It was found that the discrete ordinates method, with a higher order of Legendre polynomial expansions, underestimated the absorbed dose near the center of the phantom (i.e., low dose region). Simulations of the quadrature set 8 and the first order of the Legendre polynomial expansions proved to be the most efficient computation method in the authors’ study. The single-thread computation time of the deterministic simulation of the quadrature set 8 and the first order of the Legendre polynomial expansions was 21 min on a personal computer. Conclusions: The simulation results showed that the deterministic method can be effectively used to estimate the absorbed dose in a CTDI phantom. The accuracy of the discrete ordinates method was close to that of a Monte Carlo simulation, and the primary benefit of the discrete ordinates method lies in its rapid computation speed. It is expected that further optimization of this method in routine clinical CT dose estimation will improve its accuracy and speed.

07 ISOTOPE AND RADIATION SOURCES↗