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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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At least 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Lidar Tracking of Multiple Fluorescent Tracers: Method and Field Test

Past research and applications have demonstrated the advantages and usefulness of lidar detection of a single fluorescent tracer to track air motions. Earlier researchers performed an analytical study that showed good potential for lidar discrimination and tracking of two or three different fluorescent tracers at the same time. The present paper summarizes the multiple fluorescent tracer method, discusses its expected advantages and problems, and describes our field test of this new technique.

Eberhard, Wynn L.↗
NASA NTRS1991

Development of structural composite mirror technology for submillimeter space telescopes

The technical approach to the design, manufacturing, testing, and analytical simulation of lightweight graphite/epoxy mirrors is described. The precision segmented reflector (PSR) program has produced (1) 1.0-m graphite/epoxy panels with areal densities of 7 kg/sq m as-manufactured surface precision near 1 micron rms, (2) 0.5-m panels with figure changes less than 1 micron rms for temperature reductions of 100 K, (3) analytical performance-prediction capability with submicron accuracy relative to panel thermal distortion, and (4) a unique thermal vacuum test facility for structural composite mirrors.

Freeland, R. E.↗
NASA NTRS1993

Space Station ECLSS Integration Analysis

The Space Station Environmental Control and Life Support System (ECLSS) contract with NASA MSFC covered the time frame from 9 May 1985 to 31 Dec. 1992. The contract roughly covered the period of Space Station Freedom (SSF) development from early Phase B through Phase C/D Critical Design Review (CDR). During this time, McDonnell Douglas Aerospace-Huntsville (formerly McDonnell Douglas Space Systems Company) performed an analytical support role to MSFC for the development of analytical math models and engineering trade studies related to the design of the ECLSS for the SSF.

Source record↗
NASA NTRS1953

An analytical study of the comparative performance of six air-induction systems for turbojet-powered airplanes designed to operate at Mach numbers up to 2.0

A study is presented of inlet designs and aerodynamic characteristics of air-induction systems intended for operation with a turbojet engine operating with a constant-volume air-flow process. Two-dimensional inlet designs similar to those discussed in NACA RM A52C14, plus a fixed-geometry inlet with a convergent-divergent diffuser, and an additional variable-geometry inlet are considered for Mach numbers from 0.85 to 2.0 from sea level to the stratosphere. For best performance throughout this range of Mach numbers and altitudes, it was shown that the geometry of the inlet must be such as to insure a high pressure recovery, as well as to provide for a variable entrance area. The inlets are compared on the basis of a drag evaluation neglecting viscosity.

DIFFUSERS, SUBSONIC↗
NASA NTRS1995

The determination of the constitutive parameters of a medium with application to a reinforced concrete pad

This report describes the experimental and analytical efforts performed to determine the constitutive parameters of a reinforced concrete pad on which an aircraft (the NASA Boeing 757) was parked while its internal electromagnetic environment was measured. This concrete pad is part of the Large Electromagnetic System-Level Illuminator (LESLI) test facility at the Phillips Laboratory, Kirtland Air Force Base, New Mexico. The relative dielectric constant, conductivity, index of refraction, and reflection coefficient have been determined over the frequency range of 0 to 300 MHz and are presented.

Poggio, A. J.↗
NASA NTRS1995

Preliminary Design of a SP-100/Stirling Radiatively Coupled Heat Exchanger

Several methods for coupling the SP-100 space nuclear reactor to the NASA Lewis Research Center's Free Piston Stirling Power Convertor (FPSPC) are presented. A 25 kWe, dual opposed Stirling convertor configuration is used in these designs. The concepts use radiative coupling between the SP-100 lithium loop and the sodium heat pipe of the Stirling convertor to transfer the heat from the reactor to the convertor. Four separate configurations are presented. Masses for the four designs vary from 41 to 176 kgs. Each design's structure, heat transfer characteristics, and heat pipe performance are analytically modeled.

Schmitz, Paul↗
NASA NTRS1996

Automated clustering-based workload characterization

The demands placed on the mass storage systems at various federal agencies and national laboratories are continuously increasing in intensity. This forces system managers to constantly monitor the system, evaluate the demand placed on it, and tune it appropriately using either heuristics based on experience or analytic models. Performance models require an accurate workload characterization. This can be a laborious and time consuming process. It became evident from our experience that a tool is necessary to automate the workload characterization process. This paper presents the design and discusses the implementation of a tool for workload characterization of mass storage systems. The main features of the tool discussed here are: (1)Automatic support for peak-period determination. Histograms of system activity are generated and presented to the user for peak-period determination; (2) Automatic clustering analysis. The data collected from the mass storage system logs is clustered using clustering algorithms and tightness measures to limit the number of generated clusters; (3) Reporting of varied file statistics. The tool computes several statistics on file sizes such as average, standard deviation, minimum, maximum, frequency, as well as average transfer time. These statistics are given on a per cluster basis; (4) Portability. The tool can easily be used to characterize the workload in mass storage systems of different vendors. The user needs to specify through a simple log description language how the a specific log should be interpreted. The rest of this paper is organized as follows. Section two presents basic concepts in workload characterization as they apply to mass storage systems. Section three describes clustering algorithms and tightness measures. The following section presents the architecture of the tool. Section five presents some results of workload characterization using the tool.Finally, section six presents some concluding remarks.

Pentakalos, Odysseas I.↗
NASA NTRS2000

Design, Fabrication and Test of a High Efficiency Refractive Secondary Concentrator for Solar Applications

Common to many of the space applications that utilize solar thermal energy such as electric power conversion, thermal propulsion, and furnaces, is a need for highly efficient, solar concentration systems. An effort is underway to develop the refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. When used in combination with advanced primary concentrators, the refractive secondary concentrator enables very high system concentration ratios (10,000 to 1) and very high temperatures (greater than 2000 K). Presented is an overview of the effort at the NASA Glenn Research Center to evaluate the performance of a prototype single crystal sapphire refractive secondary concentrator and to compare the performance with analytical models. The effort involves the design and fabrication of a secondary concentrator, design and fabrication of a calorimeter and its support hardware, calibration of the calorimeter, testing of the secondary concentrator in NASA Glenn's Tank 6 solar thermal vacuum facility, and comparing the test results with predictions. Test results indicate an average throughput efficiency of 87%. It is anticipated that reduction of a known reflection loss with an anti-reflective coating would result in a secondary concentrator throughput efficiency of approximately 93%.

Wong, Wayne A.↗
NASA NTRS2005

Prospecting for In Situ Resources on the Moon and Mars Using Wheel-Based Sensors

The Apollo and Russian missions during 1970's were reviewed to rediscover the type and distribution of minerals on the Moon. This study revealed that the Moon is a relatively barren place in mineral content when compared with the Earth. Results from the Lunar minerals brought back to Earth, indicate that the Moon lacks water, hydroxyl ions, and carbon based minerals. Our approach to prospecting utilizes a vehicle with sensors embedded in a wheel that allow measurements while the vehicle is in motion. Once a change in soil composition is detected, decision making software stops the vehicle and analytical instruments perform a more definitive analysis of the soil. The focus of this paper is to describe the instrumentation and data from the wheel-based sensors.

moon↗
NASA NTRS2002

Modulation Study for Beam Steerable Reflectarray Antennas

The reflectarray antenna is a power-efficient antenna but with an inherent intersymbol interference (ISI) problem with digital modulations. The composite signal model of a reflectarray is established. The ISI is characterized by the signal components delays. The feed-to-element distance and the element-to-observation distance contribute to the total delay, with the latter having the major effect. The effect of typical phase shifters' phase errors is analyzed and evaluated. Simulations are performed. The analytical and simulation results for an example reflectarray at f(sub c) = 26.5 GHz and bit rate of 1.325 Gbps show that the BER degradation due to ISI is proportional to the symbol rate and the loss ranges from less than 1 dB to around 2 dB in E(sub b)/N(sub o), depending on original E(sub b)/N(sub o), for BPSK, QPSK, 8PSK and 16QAM. The phase error effect is negligible for lower order modulations and is unacceptable for higher order modulations such as 64 and 256QAM.

Xiong, Fuqin↗
NASA NTRS2018

A Simple Test Method for Large Deformation Bending of Thin High Strain Composite Flexures

A simple test method for large deformation bending of thin composite laminates is investigated using image processing and full-field strain measurements. The assumptions and kinematic equations that represent the test are used to calculate numerically the laminate bending stiffness and strength as well as the curvature and strains at failure. In order to validate the test methodology, a comparison is performed between analytical model predictions and empirical data in terms of computed surface strains versus digital image correlation data and calculated rotation angles of the fixture arms throughout the test versus measured ones. The new test method is then used to calculate the bending stiffness in the D11 and D22 directions as well as failure strains for various thin-ply laminates of interest. These parameters are ultimately compared with predicted values using micromechanics and classical lamination theory analysis. In general, bending stiffness and strain test results and predictions for 0 degree orientation coupons have a maximum difference of 10% and 35%.

Fernandez, Juan M.↗
NASA NTRSDate not supplied

TPSAS-NF1676L-20739-DND

Overview of LaRC's Comprehensive Digital Transformation strategy. Includes foundational items such as modeling & simulation, big data analytics, high performance computing, and advanced information technology. Builds upon the foundation to recommend advanced "virtual capabilities," such as a virtual flight test capability to complement flight testing and wind tunnels.

Ed McLarney↗
NASA NTRS2001

Ultrasonic/sonic drilling/coring (USDC) for planetary applications

One of the major limitations of sampling on Mars and other low gravity environments is the need for high axial force when using conventional drilling. To address this limitation an ultrasonic/sonic drilling/coring (USDC) mechanism has been developed that employs an ultrasonic horn driven by a piezoelectric stack. The horn dnves a free mass that resonates between the horn and drill stein. Tests have shown that the USDC addresses some of the key challenges to the NASA sampling objectives. The USDC is lightweight (450 g), requires low preload (<5N) and can be driven at low power (5W), The device has been shown to drill rocks with various levels of hardness including granite, diorite, basalt and limestone. The hammering action involved with the coring process can produce cores of various shapes, which need not necessarily be round. Because it is driven by piezoelectric ceramics, the USDC is highly tolerant to changes in its operating environment. These actuation materials can be designed to operate at a wide range of temperatures including those expected on Mars and Venus. Although the drill is driven electrically at 20 kHz, a substantial sub-harmonic acoustic component is found that is crucial to drilling performance. An analytical model has been developed to explain this low frequency coupling in the horn, free mass, drill stem and rock.

Peterson, Thomas↗
NASA NTRSDate not supplied

Signal and Power Integrity Design Methodology for High-Performance Flight Computing Systems

Computing capabilities of space systems have in-creased onboard performance by orders of magnitude with the use of radiation-tolerant field-programmable gate arrays (FPGA)and processors. The incorporation of signal and power integrity analysis with printed circuit board (PCB) design in reliable computing architectures for space systems has become critical to enable future mission capabilities. Developers launch high-performance processors into a breadth of orbits and missions, running varying applications that create challenges for designing reliable computing hardware. Specifically, for these designs, academic and industry research has focused on component radiation performance, fault mitigation, and reliable architectures. How-ever, other design parameters including electromagnetic interference (EMI), PCB stackup, signal integrity (SI), voltage regulator module (VRM) design, and power distribution network (PDN)are often deprioritized or disregarded as the design matures. Since these characteristics are becoming more significant in high-performance processor designs, this research presents a hardware design and analysis methodology for high-performance, space-computing systems that focuses on a holistic design approach and PDN reliability. While these challenges exist across all space hardware, the reduced PCB dimensions imposed by SmallSats and CubeSats introduce additional hurdles, specifically to VRM and decoupling design. By examining the relationship between the PDN and radiation performance, an analytical relationship is developed that incorporates Total Ionizing Dose and Single-Event Transients to ensure reliability throughout the mission duration. The presented design methodology is applied to the SpaceCube v3.0 Mini, an FPGA-based on-board science data processing system developed at NASA Goddard Space Flight Center.

Advanced avionics↗
NASA NTRS2024

SUPIN: A Tool for the Aerodynamic Design and Analysis of Supersonic Inlets

The Supersonic Inlet Design and Analysis Tool (SUPIN) is a computational program that performs geometric modeling and aerodynamic design and analysis of a set of supersonic inlets whose types include the axisymmetric pitot, three-dimensional pitot, axisymmetric, two-dimensional, two-dimensional bifurcated-duct, and streamline-traced inlets. The inlets are modeled by dividing the inlet flowpath into components that start at the freestream and ends at the engine face. The primary components of the inlet include the external supersonic diffuser, throat section, and subsonic diffuser. Each component is characterized by a set of inputs that include geometric and aerodynamic factors. Examples of the geometric factors are angles, lengths, area ratios, and coordinates that describe the geometry of the components. Examples of the aerodynamic factors are Mach numbers, flow ratios, and pressure ratios that set constraints or desired aerodynamic properties of the component. These input factors are specified within a text-based input data file that is read into SUPIN. SUPIN is a Fortran 95 program that performs the inlet design and analysis as a batch or non-interactive process. SUPIN writes output data files describing the inlet geometry and aerodynamic performance. SUPIN uses analytic, empirical, and numerical methods to perform the inlet design and analysis. The inlet geometry is constructed using planar and three-dimensional geometry constructs and is represented by coordinates, angles, areas, profiles, and surfaces. Surfaces are output in the form of a Plot3D surface grid file. SUPIN does have some capability to automatically generate planar and three-dimensional, multi-block, structured grids for computational fluid dynamics (CFD) analysis. The aerodynamic analysis performed by SUPIN computes quasi-one-dimensional properties, such as Mach numbers, pressures, and temperatures, through the inlet flowpath. Planar aerodynamic properties, such as those for shock and Mach waves, are computed for the supersonic compression of the external supersonic diffuser and throat section. The inlet performance is characterized by the inlet flow rates, total pressure recovery, and inlet drag. The primary intent of this document is to describe the usage of SUPIN. The methods used within SUPIN are documented and may serve as a useful reference for understanding the aerodynamic design and analysis of supersonic inlets.

supersonic inlets↗
DOE OSTI2023

Methods and systems for evaluating data transportability in distribution grids

This document describes systems and techniques for evaluating and improving distribution-grid data transportability. These systems and techniques allow engineers to quantify the data transportability of a communication system within or connected to a distribution grid, which represents an ability to transport in real-time telemetry from source locations (e.g., sensors in the distribution grid) to control mechanisms. Distribution engineers can use the sensor readings to perform grid analytics, control operating parameters, and operate protection systems. Distribution engineers can also use the transportability of the communication system to evaluate the observability of the distribution grid, which represents an ability to combine actual measurements and various types of computations (e.g., analytics, estimators, forecasters) from a system model. Distribution engineers can then generate a sensor allocation plan that indicates the number and location of sensors to maximize observability for a fixed sensor cost and/or minimize sensor cost for predetermined observability.

Taft, Jeffrey D.↗
DOE OSTI2026

Using Best Basis Inventory Data to Direct Strategies for Real Time Monitoring of Hanford High Level Waste – 26226

The potential to accelerate the processing of low- and high-level tank waste by applying real-time monitoring (RTM) of chemical and physical properties has prompted research into the suitability of multiple analytical methods for that purpose. The broad variety of waste stream properties and the large number of analytes of interest (as evidenced by Waste Acceptance Criteria (WAC) and Process Control Limit (PCL) lists) lead to an overwhelming set of possible analytical scenarios. This report describes the use of Best Basis Inventory (BBI) data to find the most relevant analytical targets for the specific case of monitoring the blending of High Level Waste from multiple tanks prior to introduction into a vitrification facility. Campaigns for blending this waste to minimize the risk of exceeding WACs and PCLs have been proposed. However, the predicted compositions of the blended materials do not incorporate any uncertainties that may be associated with the representativeness of the waste layer samples or the laboratory analyses that generated the BBI data. Also, they do not include any uncertainty associated with the precision of collecting highly specific fractions of the layers during a blending campaign or any inhomogeneities that may exist in those layers. Monte Carlo methods are used to apply uncertainties to the compositions of the individual layers specified in the campaign recipes. The resulting variations in the compositions of the blended materials allow estimation of the risks of exceeding WACs and PCLs for each campaign. A critical subset of WACs/PCLs – NOx, NaK, AlFeZr, and S – are especially at risk of being exceeded in multiple campaigns. These analytes should be the focus of instrument development. We also have extracted the expected solid/supernate distribution for these analytes, which establishes important performance criteria for individual analytical methods. The BBI data also permits an understanding of the different chemical forms in which the analytes appear. Thus, the need to establish instrumental sensitivity to these forms can be gainfully addressed. Although concentrating on one specific application – the blending of tank waste - this approach should be generalizable for the analysis of other possible RTM applications for waste processing.

Lascola, Robert [Savannah River National Laborator↗