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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 73 records · Page 4

A Validated Set of MIDAS V5 Task Network Model Scenarios to Evaluate Nextgen Closely Spaced Parallel Operations Concepts

The Closely Spaced Parallel Operations (CSPO) scenario is a complex, human performance model scenario that tested alternate operator roles and responsibilities to a series of off-nominal operations on approach and landing (see Gore, Hooey, Mahlstedt, Foyle, 2013). The model links together the procedures, equipment, crewstation, and external environment to produce predictions of operator performance in response to Next Generation system designs, like those expected in the National Airspaces NextGen concepts. The task analysis that is contained in the present report comes from the task analysis window in the MIDAS software. These tasks link definitions and states for equipment components, environmental features as well as operational contexts. The current task analysis culminated in 3300 tasks that included over 1000 Subject Matter Expert (SME)-vetted, re-usable procedural sets for three critical phases of flight; the Descent, Approach, and Land procedural sets (see Gore et al., 2011 for a description of the development of the tasks included in the model; Gore, Hooey, Mahlstedt, Foyle, 2013 for a description of the model, and its results; Hooey, Gore, Mahlstedt, Foyle, 2013 for a description of the guidelines that were generated from the models results; Gore, Hooey, Foyle, 2012 for a description of the models implementation and its settings). The rollout, after landing checks, taxi to gate and arrive at gate illustrated in Figure 1 were not used in the approach and divert scenarios exercised. The other networks in Figure 1 set up appropriate context settings for the flight deck.The current report presents the models task decomposition from the tophighest level and decomposes it to finer-grained levels. The first task that is completed by the model is to set all of the initial settings for the scenario runs included in the model (network 75 in Figure 1). This initialization process also resets the CAD graphic files contained with MIDAS, as well as the embedded operator models that comprise MIDAS. Following the initial settings, the model progresses to begin the first tasks required of the two flight deck operators, the Captain (CA) and the First Officer (FO). The task sets will initialize operator specific settings prior to loading all of the alerts, probes, and other events that occur in the scenario. As a note, the CA and FO were terms used in developing this model but the CA can also be thought of as the Pilot Flying (PF), while the FO can be considered the Pilot-Not-Flying (PNF)or Pilot Monitoring (PM). As such, the document refers to the operators as PFCA and PNFFO respectively.

task network model↗

Mission 59 to survey earth with multiband radar

The preparations for Space Shuttle Mission 59 are described, as are the planned mapping operations of the Space Imaging Radar C (SIR-C). Crew tasks and shuttle maneuvers during the 18 million square mile Earth mapping mission are also outlined.

Mckenna, James T.↗

Graphite Oxidation Studies Irradiated Graphite, GIF Summary, ASME Task Force, ASTM Activities

Introduction Comparison of Graphite Oxidation Rates for Irradiated and Unirradiated NBG-25 (Rebecca Smith and Austin Matthews, INL) Annealing effect over range of oxidation temperatures Irradiation effect (~6.5 dpa) over range of oxidation temperatures Dose dependency of irradiation effect Generation IV International Forum High Level Deliverable Summary of DOE ART Historic Oxidation Research (Cristian Contescu, ORNL) Publications issued over the last ~10 years Acute and chronic oxidation ASME Graphite Oxidation Task Force (C. Contescu, Paul Ryan, ORNL, Joe Bass, A. Matthews, R. Smith, INL) Collaborative effort headed by ORNL and engaging INL and others Initial review of relevant oxidation discussion in ASME code ASTM Activities (C. Contescu) Virtual Meetings New and Revised Standards

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Shuttle mission simulator requirements report, volume 1, revision C

The contractor tasks required to produce a shuttle mission simulator for training crew members and ground personnel are discussed. The tasks will consist of the design, development, production, installation, checkout, and field support of a simulator with two separate crew stations. The tasks include the following: (1) review of spacecraft changes and incorporation of appropriate changes in simulator hardware and software design, and (2) the generation of documentation of design, configuration management, and training used by maintenance and instructor personnel after acceptance for each of the crew stations.

Burke, J. F.↗

Propel: Tools and Methods for Practical Source Code Model Checking

The work reported here is an overview and snapshot of a project to develop practical model checking tools for in-the-loop verification of NASA s mission-critical, multithreaded programs in Java and C++. Our strategy is to develop and evaluate both a design concept that enables the application of model checking technology to C++ and Java, and a model checking toolset for C++ and Java. The design concept and the associated model checking toolset is called Propel. It builds upon the Java PathFinder (JPF) tool, an explicit state model checker for Java applications developed by the Automated Software Engineering group at NASA Ames Research Center. The design concept that we are developing is Design for Verification (D4V). This is an adaption of existing best design practices that has the desired side-effect of enhancing verifiability by improving modularity and decreasing accidental complexity. D4V, we believe, enhances the applicability of a variety of V&V approaches; we are developing the concept in the context of model checking. The model checking toolset, Propel, is based on extending JPF to handle C++. Our principal tasks in developing the toolset are to build a translator from C++ to Java, productize JPF, and evaluate the toolset in the context of D4V. Through all these tasks we are testing Propel capabilities on customer applications.

Mansouri-Samani, Massoud↗

Investigation of Rectifier Diode Failures in the NEXT-C Power Processing Unit

NASA's Evolutionary Xenon Thruster-Commercial (NEXT-C) project is tasked with developing flight electric propulsion systems, including both thrusters and power processing units (PPUs). In 2018, the beam supply in a NEXT-C engineering prototype PPU experienced an output rectifier diode failure during development thermal-vacuum testing. A failure investigation led by NASA GRC identified the root cause of the failure as a thermal runaway caused by increased reverse recovery losses in the diodes when the PPU was run at its maximum operating temperature. Significant reverse recovery performance variations were identified in diodes with the same part number but manufactured by different vendors. The failure investigation was able to collect evidence of the increased reverse recovery and replicate the diode failures in a controlled laboratory environment.

George L Thomas↗

Investigation of Rectifier Diode Failures in the NEXT-C Power Processing Unit

NASA's Evolutionary Xenon Thruster-Commercial (NEXT-C) project is tasked with developing flight electric propulsion systems, including both thrusters and power processing units (PPUs). In 2018, the beam supply in a NEXT-C engineering prototype PPU experienced an output rectifier diode failure during development thermal-vacuum testing. A failure investigation led by NASA GRC identified the root cause of the failure as a thermal runaway caused by increased reverse recovery losses in the diodes when the PPU was run at its maximum operating temperature. Significant reverse recovery performance variations were identified in diodes with the same part number but manufactured by different vendors. The failure investigation was able to collect evidence of the increased reverse recovery and replicate the diode failures in a controlled laboratory environment.

George L. Thomas↗

Modeling C–H Bond Activation and Oxidations of Alkanes over Cu–MOR Using First-Principles Methods

Direct conversion of methane to methanol can significantly boost the economic value of shale gas utilization. However, the stable C–H bond makes methane partial oxidation a challenging catalysis task. At low temperatures, C–H bond activation is kinetically sluggish. On the other hand, methane is likely oxidized fully into CO2 at high temperatures, which will lower methanol selectivity. Several Cu–oxo complexes such as mono(μ-oxo)dicopper, bis(μ-oxo)dicopper, and copper trioxo anchored in the mordenite (MOR) zeolite framework are shown to balance catalytic activity and product selectivity for the methane-to-methanol conversion. In this work, the thermodynamic stability of Cu–oxo complexes was evaluated as active centers for C–H bond activation using the BEEF-vdW functional within the density functional theory (DFT) framework, and the bis(μ-oxo)dicopper moiety was identified as the most stable configuration. The catalytic reactivity of these complexes was then tested with the activation of the first C–H bond of light hydrocarbons (i.e., methane, ethane, and propane), as well as subsequent oxidation steps to corresponding alcohols. Site II of the Cu–trioxo cluster with highest spin density remains as the most potent active site by enabling the lowest energy barrier for initial methane activation when electronic spin crossing was considered. Energy barriers for the first C–H activation step follow a decreasing order of methane, ethane, and propane.

Xu, Jiayi↗

Human operator performance of remotely controlled tasks: Teleoperator research conducted at NASA's George C. Marshal Space Flight Center

The capabilities within the teleoperator laboratories to perform remote and teleoperated investigations for a wide variety of applications are described. Three major teleoperator issues are addressed: the human operator, the remote control and effecting subsystems, and the human/machine system performance results for specific teleoperated tasks.

Shields, N., Jr.↗

Results for the first quarter calendar year 2017 tank 50H salt solution sample

In this memorandum, the chemical and radionuclide contaminant results from the First Quarter Calendar Year 2017 (CY17) sample of Tank 50H salt solution are presented in tabulated form. The First Quarter CY17 Tank 50H samples [a 200 mL sample obtained 6” below the surface (HTF-50-17-7) and a 1 L sample obtained 66” from the tank bottom (HTF-50-17-8)] were obtained on January 15, 2017 and received at Savannah River National Laboratory (SRNL) on January 16, 2017. Prior to obtaining the samples from Tank 50H, a single pump was run at least 4.4 hours and the samples were pulled immediately after pump shut down. All volatile organic analysis (VOA) and semi-volatile organic analysis (SVOA) were performed on the surface sample and all other analyses were performed on the variable depth sample. The information from this characterization will be used by Savannah River Remediation (SRR) for the transfer of aqueous waste from Tank 50H to the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This memorandum compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets. The chemical and radionuclide contaminant results from the characterization of the First Quarter CY17 sampling of Tank 50H were requested by SRR personnel and details of the testing are presented in the SRNL Task Technical and Quality Assurance Plan (TTQAP). This memorandum is part of Deliverable 2 from SRR request. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the TTQAP for the Tank 50H saltstone task.

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Results for the First Quarter Calendar Year 2018 Tank 50 Salt Solution Sample

In this Technical Report, the chemical and radionuclide contaminant results from the First Quarter Calendar Year 2018 (CY18) sample of Tank 50 salt solution are presented in tabulated form. The information from this characterization will be used by Savannah River Remediation (SRR) for the transfer of aqueous waste from Tank 50 to the Saltstone Production Facility, where the waste will be treated and disposed of in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to Saltstone Waste Acceptance Criteria (WAC) limits and targets. The chemical and radionuclide contaminant results from the characterization of the First Quarter CY18 sampling of Tank 50 were requested by SRR personnel via a Task Technical Request (TTR) 2 and details of the testing are presented in the Savannah River National Laboratory (SRNL)Task Technical and Quality Assurance Plan (TT QAP). This Technical Report is part of Deliverable 2 relating to Task 1 from the SRR request. 2 Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the TTQAP for the Tank 50 Saltstone task.

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Results for the Third Quarter Calendar Year 2018 Tank 50 Salt Solution Sample

In this Technical Report, the chemical and radionuclide contaminant results from the Third Quarter Calendar Year 2018 (CY18) sample of Tank 50 salt solution are presented in tabulated form. The information from this characterization will be used by Savannah River Remediation (SRR) for the transfer of aqueous waste from Tank 50 to the Saltstone Production Facility, where the waste will be treated and disposed in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to Saltstone Production Facility (SPF) Waste Acceptance Criteria (WAC) limits and targets. The chemical and radionuclide contaminant results from the characterization of the Third Quarter CY18 sampling of Tank 50 were requested by SRR personnel via a Task Technical Request (TTR) and details of the testing are presented in the Savannah River National Laboratory (SRNL) Task Technical and Quality Assurance Plan (TTQAP). This Technical Report is part of Deliverable 2 relating to Task 1 from the SRR request. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the TTQAP for the Tank 50 Saltstone task.

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Results for the Fourth Quarter Calendar Year 2018 Tank 50 Salt Solution Sample

In this Technical Report, the chemical and radionuclide contaminant results from the Fourth Quarter Calendar Year 2018 (CY18) sample of Tank 50 salt solution are presented in tabulated form. The information from this characterization will be used by Savannah River Remediation (SRR) for the transfer of aqueous waste from Tank 50 to the Saltstone Production Facility (SPF), where the waste will be treated and disposed in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to SPF Waste Acceptance Criteria (WAC) Limits and Targets. The chemical and radionuclide contaminant results from the characterization of the Fourth Quarter CY18 sampling of Tank 50 were requested by SRR personnel via a Task Technical Request (TTR) and details of the testing are presented in the Savannah River National Laboratory (SRNL) Task Technical and Quality Assurance Plan (TTQAP). This Technical Report is part of Deliverable 2 relating to Task 1 from the SRR request. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the TTQAP for the Tank 50 Saltstone task.

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Results for the Fourth Quarter Calendar Year 2018 Tank 50 Salt Solution Sample

In this Technical Report, the chemical and radionuclide contaminant results from the Fourth Quarter Calendar Year 2018 (CY18) sample of Tank 50 salt solution are presented in tabulated form. The information from this characterization will be used by Savannah River Remediation (SRR) for the transfer of aqueous waste from Tank 50 to the Saltstone Production Facility (SPF), where the waste will be treated and disposed in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to SPF Waste Acceptance Criteria (WAC) Limits and Targets. The chemical and radionuclide contaminant results from the characterization of the Fourth Quarter CY18 sampling of Tank 50 were requested by SRR personnel via a Task Technical Request (TTR) and details of the testing are presented in the Savannah River National Laboratory (SRNL) Task Technical and Quality Assurance Plan (TTQAP). This Technical Report is part of Deliverable 2 relating to Task 1 from the SRR request. Data pertaining to the regulatory limits for Resource Conservation and Recovery Act (RCRA) metals will be documented at a later time per the TTQAP for the Tank 50 Saltstone task.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗