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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Traceability of Software Safety Requirements in Legacy Safety Critical Systems

How can traceability of software safety requirements be created for legacy safety critical systems? Requirements in safety standards are imposed most times during contract negotiations. On the other hand, there are instances where safety standards are levied on legacy safety critical systems, some of which may be considered for reuse for new applications. Safety standards often specify that software development documentation include process-oriented and technical safety requirements, and also require that system and software safety analyses are performed supporting technical safety requirements implementation. So what can be done if the requisite documents for establishing and maintaining safety requirements traceability are not available?

Hill, Janice L.↗
NASA NTRS2016

Evaluation of GLAMR-Based Calibration for SI-Traceable Field Reflectance Retrievals

The reflected solar instrument that is part of the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission is being formulated with a goal of providing SI-traceable measurement of radiance that is an order of magnitude more accurate than the current imaging sensors. The Goddard Laser for Absolute Measurement of Radiance (GLAMR) is a key element to reaching such accuracy along with transferring the laboratory calibration to on-orbit measurements. Results from field reflectance retrievals using three separate instruments all of which have been calibrated using GLAMR are shown. The instruments include a commercial field spectrometer and a portable version of CLARREO's calibration demonstration system. The third instrument is NASA Goddard's Lidar, Hyperspectral and Thermal Imager (G-LiHT) which is an airborne system. All three were operated during a March 2013 measurement campaign at Red Lake Playa, Arizona as part of the on-orbit commissioning phase of Landsat 8. Reflectance is derived from near-coincident measurements by the three sensors for a small area of the playa. The retrieved results are SI-traceable and demonstrate the ability to transfer the GLAMR calibration to the field. Use of the G-LiHT data in the calibration of Landsat-7 and -8 sensors permits them both to be placed on the GLAMR-scale as well.

Angal, Amit↗
NASA NTRS2017

Importance of Calibration/Validation Traceability for Multi-Sensor Imaging Spectrometry Applications

Knowledge of calibration traceability is essential for ensuring the quality of data products relying on multiple sensors and especially true for imaging spectrometers. The current work discusses the expected impact that imaging spectrometers have in ensuring radiometric traceability for both multispectral and hyperspectral products. The Climate Absolute Radiance and Refractivity Observatory Pathfinder mission is used to show the role that high-accuracy imaging spectrometers can play in understanding test sites used for vicarious calibration of sensors. The associated Solar, Lunar for Absolute Reflectance Imaging Spectroradiometer calibration demonstration system is used to illustrate recent advances in laboratory radiometric calibration approaches that will allow both the use of imaging spectrometers as calibration standards as well as to ensure the consistency of the multiple imaging spectrometers expected to be on orbit in the next decade.

imagin↗
DOE OSTI2022

Traceability of Surface Longwave Irradiance Measurements to SI Using the IRIS Radiometers: Preprint

The World Radiation Center at PMOD/WRC is operated on behalf of the WMO. The Infrared Radiometry Section of the WRC (WRC-IRS) provides traceability of downwelling atmospheric longwave radiation measured with pyrgeometers by comparison to the World Infrared Standard Group (WISG) [1]. As has been discussed previously [2], the current implementation of the WISG measures lower longwave irradiances than the two candidate reference radiometers IRIS (Infrared Integrating Sphere Radiometer) and the ACP (Absolute Cavity Pyrgeometer). To validate the findings reported in [2], additional measurements since that publication in 2014 have been performed and are discussed in this paper. Specifically, Measurements during cloud-free nights at PMOD/WRC between the WISG and IRIS radiometers, A field campaign at the Atmospheric Radiation Monitoring Site (ARM) at Southern Great Plains, Oklahoma with IRIS, ACP, AERI (Atmospheric Emittance Radiance Interferometer) and WISG traceable pyrgeometers, Laboratory comparison between the reference blackbody of PMOD/WRC with the hemispherical blackbody developed by PTB.

ACR↗
DOE OSTI2022

Failure Mechanism Traceability and Application in Human System Interface of Nuclear Power Plants using RESHA

In recent years, there has been considerable effort to modernize existing and new nuclear power plants with digital instrumentation and control systems (DI&C). However, there has also been considerable concern both by industry and regulatory bodies for the risk and consequence analysis of these systems. Of particular concern are digital common cause failures (CCFs) specifically related to software defects. These “misbehaviors” by the software can occur in both the control and monitoring of a system. While many new methods have been proposed to identify potential software failure modes, such as Systems-theoretic Process Analysis (STPA), Hazard and Consequence Analysis for Digital Systems (HAZCADS), etc., these methods are focused primarily on the control action pathway of a system. In contrast, the information feedback pathway lacks unsafe control actions (UCAs), which are typically related to software basic events; thus, assessment of software basic events in such systems is unclear. In this work, we present the idea of intermediate processors and unsafe information flow (UIF) to help safety analysts trace failure mechanisms in the feedback pathway and how they can be integrated into a fault tree for improved assessment capability. The concepts presented are demonstrated in two comprehensive case studies, a smart sensor integrated platform for unmanned autonomous vehicles and another on a representative advanced human system interface (HSI) for safety critical plant monitoring. The qualitative software basic events are identified, and a fault tree analysis is conducted based on a modified Redundancy-guided Systems-theoretic Hazard Analysis (RESHA) methodology. The case studies demonstrate the use of UIF and intermediate processors in the fault tree to improve traceability of software failures in highly complex digital instrumentation feedback. The improved method can also clarify fault tree construction when multiple component dependencies are present in the system.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Failure Mechanism Traceability and Application in Human System Interface of Nuclear Power Plants using RESHA

In recent years, there has been considerable effort to modernize existing and new nuclear power plants with digital instrumentation and control systems (DI&C). However, there has also been considerable concern both by industry and regulatory bodies for the risk and consequence analysis of these systems. Of particular concern are digital common cause failures (CCFs) specifically related to software defects. These “misbehaviors” by the software can occur in both the control and monitoring of a system. While many new methods have been proposed to identify potential software failure modes, such as Systems-theoretic Process Analysis (STPA), Hazard and Consequence Analysis for Digital Systems (HAZCADS), etc., these methods are focused primarily on the control action pathway of a system. In contrast, the information feedback pathway lacks unsafe control actions (UCAs), which are typically related to software basic events; thus, assessment of software basic events in such systems is unclear. In this work, we present the idea of intermediate processors and unsafe information flow (UIF) to help safety analysts trace failure mechanisms in the feedback pathway and how they can be integrated into a fault tree for improved assessment capability. The concepts presented are demonstrated in two comprehensive case studies, a smart sensor integrated platform for unmanned autonomous vehicles and another on a representative advanced human system interface (HSI) for safety critical plant monitoring. The qualitative software basic events are identified, and a fault tree analysis is conducted based on a modified Redundancy-guided Systems-theoretic Hazard Analysis (RESHA) methodology. The case studies demonstrate the use of UIF and intermediate processors in the fault tree to improve traceability of software failures in highly complex digital instrumentation feedback. The improved method can also clarify fault tree construction when multiple component dependencies are present in the system.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Plutonium isotope ratio measurements by total evaporation-thermal ionization mass spectrometry (TE-TIMS): an evaluation of uncertainties using traceable standards from the New Brunswick Laboratory

The accuracy and precision of isotope amount ratio measurements using thermal ionization mass spectrometry (TIMS) instrumentation are described, and the measurement of Pu materials is emphasized. The mass fractionation observed for Am, Ga, Pu, and U for isotope amount ratio measurements using the total evaporation (TE) technique is compared with theoretical estimates to demonstrate the advantage of the TE methodology and to investigate systematic biases in the major isotope amount ratios of U and Pu certified reference material (CRM) standards from the U.S. provider of CRMs. The quality of the Pu isotopic data generated by TIMS instruments in an analytical laboratory is demonstrated by the application of the double ratio technique to estimate the 241 Pu half-life. Analytical data on traceable Pu CRMs from the New Brunswick Laboratory (NBL), generated as part of routine measurements supporting various programs, are used for this half-life estimation. Although the 241 Pu abundances in CRMs of 136, 137, 138, and 126-A are approximately 200–2000× smaller than those in the 241 Pu material used in the previous Institute for Reference Materials and Measurements (IRMM) evaluation of the 241 Pu half-life, the half-life value estimated in this work shows excellent agreement with the currently accepted value from the IRMM. This agreement also demonstrates the pedigree of the Pu isotopic standards from the NBL and the quality of the isotope amount ratio measurements using TIMS instrumentation. For both the major and minor Pu isotope amount ratios, this report describes the relative importance of the factors affecting the uncertainty of TIMS measurements, which are considered the gold standard in isotope ratio measurements (LA-UR-24-29199).

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2024

Traceable Device-Independent Randomness as a Service

We implement a traceable protocol for device-independent random number generation. Our demonstration involves transparently integrating a device-independent RNG into a public randomness beacon, and feeding 7434 random number pulses into the beacon over 39 days.

Kavuri, Gautam A.↗
DOE OSTI2025

Utilization of traceable standards to validate plutonium isotopic purification and separation of plutonium progeny using AG MP-1M resin for nuclear forensic investigations

Radio-chronometric studies on plutonium (Pu) materials require independent measurement of the Pu (parent) content and isotopic distribution as well as concentration and isotopic distribution of the plutonium isotopic decay products. We performed a series of experiments to demonstrate the consistency of separations using the Lewatit MP 800 macroporous anion exchange resin and the AG MP-1M resin with traceable Pu isotopic certified reference material (CRM) standards 136, 137, 138, and 126-A. Two different mesh-sizes of the AG MP-1M resin were tested and the 50–100 mesh size resin was found to work more efficiently for the separation task. Both Lewatit and AG MP-1M resins were found to perform satisfactorily for quantitatively extracting the americium (Am) and uranium (U) progeny as well as gallium (Ga) present as a tracer in the Pu material. Both resins were effective in removing isobaric interferences from the Pu fraction used in isotopic measurements by thermal ionization mass spectrometry (TIMS). To address the co-elution of uranium and gallium, Alizarin red S (ARS) was used as a colorimetric dye to determine the behavior of UO 2 2+ and Ga 3+ on AG MP-1M resin with various acidic solutions as eluents using UV–vis spectra. Poor resolution of these peaks complicated quantitative analysis by UV–vis spectroscopy, but these results were informative in planning automated separation experiments by HPLC. LA-UR-24-28919.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2021

Document Traceability Internal Audit of the Analytical Laboratory Report on 08-26-2021

An internal audit was performed in ALAB 8/25/21 to the NELAC 2016 Standard requirements using the NELAC 2016 checklist (TNI 2016 CSDP-Volume1Checklist-Master-2-15-18-v9). The scope of the internal audit was a document traceability of the environmental testing in LRF-00118, LRF00095, and LRF 00133 performed in ALAB. The internal audit resulted in five deficiencies and two comments. The deficiencies were addressed using the ALAB non-conformance reporting system, see ALAB NCRs 10002742-10002746. FRM-5100 Management Observation and NCRs are attached.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

NREL Comparison of Absolute Cavity Pyrgeometers, InfraRed Integrating Sphere, and Pyrgeometers Traceable to World Infrared Standard Group: September 26-October 7, 2022

The comparison of the absolute cavity pyrgeometers (ACPs) with the InfraRed Integrating Sphere (IRIS), Eppley Precision Infrared Radiometer (PIR) pyrgeometers, and Kipp & Zonen (KZ) pyrgeometers traceable to the World Infrared Standard Group (WISG) was held during NREL ACP and IRIS Comparisons (NAIC) from September 26 to October 7, 2022. Data from all instruments was collected during nighttime clear sky conditions only. The irradiance measured by the ACPs is collected in 30 seconds intervals during the measurement period of two hours, and 10 seconds intervals during the calibration period of 6 minutes. During the comparison, the average (av) irradiance difference measured by ACPs and IRIS varied from -0.80 W/m2 to 0.29 W/m2 and standard deviation (sd) from 0.98 W/m2 to 1.78 W/m2. The average irradiance difference measured by ACP95F3 minus the irradiance measured by all pyrgeometers varied from 2.07 to 5.03 W/m2 with sd from 2.64 W/m2 to 2.67 W/m2.

14 SOLAR ENERGY↗
DOE OSTI2023

NREL Comparison of Absolute Cavity Pyrgeometers, InfraRed Integrating Sphere, and Pyrgeometers Traceable to World Infrared Standard Group: September 25-October 6, 2023

The comparison of the absolute cavity pyrgeometers (ACPs) with the InfraRed Integrating Sphere (IRIS), Eppley Precision Infrared Radiometer (PIR) pyrgeometers, and Kipp & Zonen (KZ) pyrgeometers traceable to the World Infrared Standard Group (WISG) was held during NREL ACP and IRIS Comparisons (NAIC) from September 25 to October 6, 2023. Data from all instruments was collected during nighttime clear sky conditions only. The irradiance measured by the ACPs is collected in 30 seconds intervals during the measurement period of two hours, and 10 seconds intervals during the calibration period of 6 minutes. During the comparison, the average (av) irradiance difference measured by ACPs and IRIS9 varied from -0.75 W/m 2 to 0.76 W/m 2 , standard deviation (sd) from 0.78 W/m 2 to 1.04 W/m 2 , and uncertainty U95 from 1.96 W/m 2 to 2.07 W/m 2 . The average irradiance difference measured by ACP95F3 minus the irradiance measured by all pyrgeometers varied from 1.64 to 3.96 W/m 2 , sd from 1.70 W/m 2 to 1.86 W/m 2 , and uncertainty U 95 from 3.78 W/m 2 to 5.42W/m 2 . Note that from September 25th at 18:31 to September 29 th at 5:30 ACP96F3 irradiance is calculated using Bruce, et al 2023 method.

47 OTHER INSTRUMENTATION↗
NASA NTRS1966

Product traceability for NASA space systems

Identification as a specific point in a quality publication revealed in the year 1962, that it was a somewhat controversial subject with something lacking in groundrule definitions. The basic key to 'traceability' is establishment of proper identification numbers. These are: (1) serial numbers for control of individual articles, assemblies or equipment; (2) lot numbers for control of materials, articles and/or assemblies produced in homogeneous groups or through a controlled process; (3) date codes on articles or materials made by a continuous or controlled process and on such items subject to variations or degradation with age; or (4) combinations of the above.

Dyer, Morris K.↗
NASA NTRS1996

GPS Disciplined Oscillators for Traceability to the Italian Time Standard

The Istituo Elettrotecnico Nazionale (IEN) is one of the Italian primary institutes which is responsible for the accreditation of secondary laboratories belong to the national calibration system (SNT) established by law in 1991. The Times and Frequency Department that has accredited in this frame 14 calibration centers for frequency, performs also the remote calibration of their reference oscillators by means of different synchronization systems. The problem of establishing the traceability of the national time standard of the Global Positioning System (GPS) disciplined oscillators has been investigated and the results obtained are reported.

Cordara, Franco↗
NASA NTRS2004

Automating Traceability for Generated Software Artifacts

Program synthesis automatically derives programs from specifications of their behavior. One advantage of program synthesis, as opposed to manual coding, is that there is a direct link between the specification and the derived program. This link is, however, not very fine-grained: it can be best characterized as Program is-derived- from Specification. When the generated program needs to be understood or modified, more $ne-grained linking is useful. In this paper, we present a novel technique for automatically deriving traceability relations between parts of a specification and parts of the synthesized program. The technique is very lightweight and works -- with varying degrees of success - for any process in which one artifact is automatically derived from another. We illustrate the generality of the technique by applying it to two kinds of automatic generation: synthesis of Kalman Filter programs from speci3cations using the Aut- oFilter program synthesis system, and generation of assembly language programs from C source code using the GCC C compilel: We evaluate the effectiveness of the technique in the latter application.

Richardson, Julian↗
NASA NTRS2006

Establishing and Verifying the Traceability of Remote-Sensing Measurements to International Standards

This viewgraph presentation reviews the principles of establishing and verifying the traceability of remote sensing measurements to national and international scales. Doing this allows comparisons to be made independent of time or locale, and improves understanding of instrument performance, provides confidence in the accuracy of the measurements, improves measurement accuracy and helps contractors understand and meet agency requirements, protecting contractor and customer.

Fraser, Gerald T.↗
NASA NTRS2014

Improved Traceability of Mission Concept to Requirements Using Model Based Systems Engineering

Model Based Systems Engineering (MBSE) has recently been gaining significant support as a means to improve the traditional document-based systems engineering (DBSE) approach to engineering complex systems. In the spacecraft design domain, there are many perceived and propose benefits of an MBSE approach, but little analysis has been presented to determine the tangible benefits of such an approach (e.g. time and cost saved, increased product quality). This thesis presents direct examples of how developing a small satellite system model can improve traceability of the mission concept to its requirements. A comparison of the processes and approaches for MBSE and DBSE is made using the NASA Ames Research Center SporeSat CubeSat mission as a case study. A model of the SporeSat mission is built using the Systems Modeling Language standard and No Magics MagicDraw modeling tool. The model incorporates mission concept and requirement information from the missions original DBSE design efforts. Active dependency relationships are modeled to analyze the completeness and consistency of the requirements to the mission concept. Overall experience and methodology are presented for both the MBSE and original DBSE design efforts of SporeSat.

Systems Engineering↗