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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Prognostics and Health Monitoring: Application to Electric Vehicles

As more and more electric vehicles emerge in our daily operation progressively, a very critical challenge lies in the prediction of remaining driving-time distance (for cars) or flying time-distance (for aircraft). This information is important, particularly in the case of unmanned vehicles, because such vehicles can become self-aware, autonomously compute its own capabilities, and identify how to best plan and successfully complete vehicular missions safely. In case of electric aircrafts, computing remaining flying time is also safety-critical, since an aircraft that runs out of power (battery charge) while in the air will eventually lose control leading to catastrophe. In order to tackle and solve the prediction problem, it is essential to have awareness of the current state and health of the system, especially since it is necessary to perform condition-based predictions. To be able to predict the future state of the system, it is also required to possess knowledge of the current and future operations of the vehicle.

Electric Vehicles↗
NASA NTRSDate not supplied

Model Based Approaches for Fault Detection, Prognostics, Decision Making in Complex Systems

The presentation discusses application of model based approaches to complex systems. The model is composed of physics-derived and empirical equations, integrated with connected networks that are strategically placed within the model to substitute equations that are subject to large uncertainty. Polynomial fit driven by heuristics or empirical observations can be substituted by more flexible networks that can minimize the error between model predictions and observations without being restricted to a predefined functional form. This modeling strategy allows training of networks deep inside the model and unknown parameters in a single learning stage.

Physics Informed↗
NASA NTRS2024

Performance of Two Battery Prognostic Applications used by Two Octocopters for Safe Low Altitude Autonomous Flight Operations

This paper addresses the problem of building trust in online predictions of the remaining available flying time for two different electric Unmanned Aerial Vehicles (eUAVs) powered by lithium-ion-polymer batteries. Flight tests for various automation research missions for the two vehicles were monitored using two on-board battery health management applications to make predictions of the remaining flying time (RFT) for each eUAV and to predict the state of the battery. Playback of the voltage, current and temperature profiles of the battery discharge were used to assess the accuracy of the estimation of the voltage and the charge states of the models as well as the estimate of the RFT. The reference ground truth values were the observed landing time and the measured battery pack resting pack voltage 20 minutes after the flight. The predicted RFT, state of charge (SoC), and state of energy (SoE) were compared with the observed results. Noise values of one standard deviation from the mean values of the internal charge states of the battery model during a reference run were used to vary the states during simulation. One application used an equivalent circuit model of the electrical dynamics of the battery pack, and the other application used a reduced-order electrochemistry model. The variation of the model state components was compared to the variation in the estimate of the RFT and the variation in the SoE to estimate a confidence factor. Variation in the estimates caused by factors affecting the off-line laboratory parameter identification experiments is considered. Variation in the estimates due to environmental factors are discussed.

Assurance↗
DOE OSTI2014

Controlling O&M Costs of Advanced SMRs using Prognostics and Enhanced Risk Monitoring

Advanced small modular reactors (AdvSMRs) can contribute to safe, sustainable, and carbon-neutral energy production. The economics of small reactors (including AdvSMRs) will be impacted by the reduced economy-of-scale savings when compared to traditional light water reactors. The most significant controllable element of the day-to-day costs involves operations and maintenance (O&M). Enhancing affordability of AdvSMRs through technologies that help control O&M costs will be critical to ensuring their practicality for wider deployment.A significant component of O&M costs is the management and mitigation of degradation of components due to their impact on planning maintenance activities and staffing levels. Technologies that help characterize real-time risk of failure of key components are important in this context. Given the possibility of frequently changing AdvSMR plant configurations, approaches are needed to integrate three elements – advanced plant configuration information, equipment condition information, and risk monitors – to provide a measure of risk that is customized for each AdvSMR unit and support real-time decisions on O&M. This article describes an overview of ongoing research into diagnostics/prognostics and enhanced predictive risk monitors (ERM) for this purpose.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2019

Endovascular Treatment of Post-thrombotic Venous Ilio-Femoral Occlusions: Prognostic Value of Venous Lesions Caudal to the Common Femoral Vein

Objectives: To propose a scale of severity for post-thrombotic venous lesions (PTVLs) after ilio-femoral deep venous thrombosis and to compare the grade with the results of endovascular treatment of ilio-femoral PTVLs. Methods: In this retrospective monocentric observational study, we included 95 patients treated for ilio-femoral PTVLs. We proposed a four-grade scale evaluating the severity of PTVLS caudal to the common femoral vein based on CT phlebography and per-operative phlebography. For most patients, venous patency was assessed with color duplex ultrasonography and the clinical efficacy of the intervention using the Villalta and CIVIQ scores. Results: Recanalization was successful in 100% of patients with a morbidity rate of 4%. After a mean follow-up of 21 months, the overall primary patency was 75%, the assisted primary patency 82%, and the secondary patency 93%. Secondary patency was 100% for grade 0–1, 90% for grade 2, and 63% for grade 3 (p < 0.002). There was no correlation between the extension of stenting caudally of the common femoral vein and venous patency. The mean improvements in the Villalta and CIVIQ-20 scores were, respectively, 4.6 (p < 0.0001) and 18 (p < 0.0001); scores were not correlated with the grade of PTVLs in the thigh. Conclusion: Venous patency after endovascular treatment of ilio-femoral PTVLs was strongly linked to the severity of PTVLs caudal to the common femoral vein but not to the extent of stenting.

62 RADIOLOGY AND NUCLEAR MEDICINE↗