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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Multiscale modeling of fission gas behavior in U 3 Si 2 under LWR conditions

In this work, we present a model of fission gas behavior in U 3 Si 2 under light water reactor (LWR) conditions for application in engineering fuel performance codes. The model includes components for intra-granular and inter-granular behavior of fission gases. The intra-granular component is based on cluster dynamics and computes the evolution of intra-granular fission gas bubbles and swelling coupled to gas diffusion to grain boundaries. The inter-granular component describes the evolution of grain-boundary fission gas bubbles coupled to fission gas release. Given the lack of experimental data for U 3 Si 2 under LWR conditions, the model is informed with parameters calculated via atomistic simulations. In particular, we derive fission gas diffusivities through density functional theory calculations, and the re-solution rate of fission gas atoms from intra-granular bubbles through binary collision approximation calculations. Further, the developed model is applied to the simulation of an experiment for U 3 Si 2 irradiated under LWR conditions available from the literature. Results point out a credible representation of fission gas swelling and release in U 3 Si 2 . Finally, we perform a sensitivity analysis for the various model parameters. Based on the sensitivity analysis, indications are derived that can help in addressing future research on the characterization of the physical parameters relative to fission gas behavior in U 3 Si 2 . The developed model is intended to provide a suitable infrastructure for the engineering scale calculation of fission gas behavior in U 3 Si 2 that exploits a multiscale approach to fill the experimental data gap and can be progressively improved as new lower-length scale calculations and validation data become available.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Observation and Modeling of Dynamic Fracture Behaviors of Battery Cell Under Impact Loading Using Enhanced Representative Volume Element Concept

The burgeoning electric automobile industry has increased interest in battery safety. Battery cells experience significant mechanical stress during operation, including the impact of accidents and vibrations from driving. The potential for thermal runaway reactions in battery cells raises safety concerns. Although numerous researchers have defined the dynamic behavior of battery cells and proposed numerical models to describe it, few studies have focused on the high-strain rate mechanical impact phase correlated with the onset of fracture. In this study, we describe the dynamic behavior of pouch battery cells and propose a modeling method to study their mechanical failure under impact situations. Impact tests are conducted at various velocities and heights. To overcome numerical issues commonly encountered under rapid deformation scenarios, a new finite element model is developed based on the representative volume element model. The proposed approach efficiently simulates continuous crack propagation and brittleness behavior during impact by permitting the individual behavior of the cell components. Therefore, engineers can reliably design safer electric vehicle battery cells by measuring the properties of the cell components.

ENERGY STORAGE↗
DOE OSTI2020

Rheological behavior and fiber spinning of polyacrylonitrile (PAN)/Carbon nanotube (CNT) dispersions at high CNT loading

Rheological studies play an important role in polymer processing including fiber spinning. In the current work, rheological behavior has been studied for polyacrylonitrile (PAN)/carbon nanotube (CNT) dispersions in dimethyl formamide (DMF), where CNT loading is as high as 15 wt% of the total solids (polymer + CNT). The presence of CNTs increased the elastic-like and shear thinning behavior of the dispersions. The terminal slope of the log G' versus log G" curve, which was used to characterize the homogeneity of solution or dispersion, is dependent on the CNT concentration but independent of temperature between 0 and 60 °C. PAN/CNT-10 (90 wt% PAN +10 wt% CNT) and PAN/CNT-15 were gel spun at different conditions, with small diameter capillary at high shear rate and large diameter capillary at relatively low shear rate. Additionally, for PAN/CNT-10, fiber spinning with lower molecular weight polymer showed increased continuous jetting time when compared to spinning with higher molecular weight polymer. In addition, the rheological behavior of PAN/cellulose nanocrystal (CNC) dispersion with 20–60 wt% CNC was also compared to that of the PAN/CNT dispersions. PAN/CNC and PAN/CNT share similarities in both rheological behavior and fiber spinning at high filler loading.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Assessment of occupant-behavior-based indoor air quality and its impacts on human exposure risk: A case study based on the wildfires in Northern California

he recent wildfires in California, U.S., have caused not only significant losses to human life and property, but also serious environmental and health issues. Ambient air pollution from combustion during the fires could increase indoor exposure risks to toxic gases and particles, further exacerbating respiratory conditions. This work aims at addressing existing knowledge gaps in understanding how indoor air quality is affected by outdoor air pollutants during wildfires -- by taking into account occupant behaviors (e.g., movement, operation of windows and air-conditioning) which strongly influence building performance and occupant comfort. A novel modeling framework was developed to simulate the indoor exposure risks considering the impact of occupant behaviors by integrating building energy and occupant behaviour modeling with computational fluid dynamics simulation. Occupant behaviors were found to exert significant impacts on indoor air flow patterns and pollutant concentrations, based on which, certain behaviors are recommended during wildfires. Further, the actual respiratory injury level under such outdoor conditions was predicted. The modeling framework and the findings enable a deeper understanding of the actual health impacts of wildfires, as well as informing strategies for mitigating occupant health risk during wildfires.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

“Teens are from Mars, Adults are from Venus”: Analyzing and Predicting Age Groups with Behavioral Characteristics in Instagram

We present behavioral characteristics of teens and adults in Instagram and prediction of them from their behaviors. Based on two independently created datasets from user profiles and tags, we identify teens and adults, and carry out comparative analyses on their online behaviors. Our study reveals: (1) significant behavioral differences between two age groups; (2) the empirical evidence of classifying teens and adults with up to 82% accuracy, using traditional predictive models, while two baseline methods achieve 68% at best; and (3) the robustness of our models by achieving 76%—81% when tested against an independent dataset obtained without using user profiles or tags.

behavioral patterns and detection of teens in soci↗
DOE OSTI2016

Interactions of aquatic animals with the ORPC OCGen® in Cobscook Bay, Maine: Monitoring behavior change and assessing the probability of encounter with a deployed MHK device

Commercial viability of the marine hydrokinetic (MHK) energy industry is contingent on numerous and diverse factors. A major factor is the effects deployed devices have on animals. This factor is multi-faceted since it is dependent on the availability of appropriate scientific approaches to detect these effects. One of the animal groups with overlapping distributions of MHK devices are fishes. As such, individual fish behavior is likely to be influenced by the presence and operation of MHK devices. Depending on the scale of deployment there are implications for changes to essential fish habitat and effects that can be explored during deployment of a single device yet most changes are likely to be realized when multiple devices are deployed over large areas. It is not only important to document these effects and examine the need for mitigation, but also determine whether the methods involved can be used within the economic constraints of this nascent industry. The results presented in this report benefit the MHK industry by providing transferrable environmental monitoring approaches for MHK projects, specifically related to the interactions between static and dynamic tidal turbines and fish. In addition, some of the data can be used to generalize conditions (e.g., the temporal periodicity of fish presence in tidal regions and probability of fish encountering a device) at other MHK sites with similar physical conditions and fish assemblages. Ocean Renewable Power Company, LLC (ORPC) deployed and tested a prototype OCGen® tidal module in Cobscook Bay, Maine, in the summer of 2014. University of Maine researchers proposed an approach to inform other researchers, regulators, and industry members of the effects of this deployment on fish. While the approach was specifically applied to the OCGen® module, results are applicable to other pilot projects and inform future array deployments. Research funded under this grant allowed us to quantify fish presence as well as individual and group-level behavior changes in the presence of the deployed OCGen® module along with a bottom support frame from a previously deployed device (TidGen®). Specific objectives associated with fish behavior changes were (1) continuation of two long-term datasets: (a) stationary down-looking hydroacoustic dataset near an MHK device (group-level) and (b) stationary side-looking hydroacoustics near the bottom-support frame of a previously deployed MHK device (individual-level); (2) application of new processing methods to down-looking hydroacoustic datasets to improve fish species identification (group-level); and (3) development of an encounter probability model using data on fish abundance, vertical distribution, and behavior.

16 TIDAL AND WAVE POWER↗
DOE OSTI2022

Conflicting Information and Compliance With COVID-19 Behavioral Recommendations

The prevalence of COVID-19 is shaped by behavioral responses to recommendations and warnings. Available information on the disease determines the population’s perception of danger and thus its behavior; this information changes dynamically, and different sources may report conflicting information. We study the feedback between disease, information, and stay-at-home behavior using a hybrid agent-based-system dynamics model that incorporates evolving trust in sources of information. We use this model to investigate how divergent reporting and conflicting information can alter the trajectory of a public health crisis. The model shows that divergent reporting not only alters disease prevalence over time, but also increases polarization of the population’s behaviors and trust in different sources of information.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2004

The effects of proton exposure on neurochemistry and behavior

Future space missions will involve long-term travel beyond the magnetic field of the Earth, where astronauts will be exposed to radiation hazards such as those that arise from galactic cosmic rays. Galactic cosmic rays are composed of protons, alpha particles, and particles of high energy and charge (HZE particles). Research by our group has shown that exposure to HZE particles, primarily 600 MeV/n and 1 GeV/n 56Fe, can produce significant alterations in brain neurochemistry and behavior. However, given that protons can make up a significant portion of the radiation spectrum, it is important to study their effects on neural functioning and on related performance. Therefore, these studies examined the effects of exposure to proton irradiation on neurochemical and behavioral endpoints, including dopaminergic functioning, amphetamine-induced conditioned taste aversion learning, and spatial learning and memory as measured by the Morris water maze. Male Sprague-Dawley rats received a dose of 0, 1.5, 3.0 or 4.0 Gy of 250 MeV protons at Loma Linda University and were tested in the different behavioral tests at various times following exposure. Results showed that there was no effect of proton irradiation at any dose on any of the endpoints measured. Therefore, there is a contrast between the insignificant effects of high dose proton exposure and the dramatic effectiveness of low dose (<0.1 Gy) exposures to 56Fe particles on both neurochemical and behavioral endpoints. Published by Elsevier Ltd on behalf of COSPAR.

Non-NASA Center↗
NASA NTRSDate not supplied

Behavioral Indicators in Air Traffic Control: Detecting and Preventing Performance Decline

Air traffic controllers are responsible for the safety and efficiency of air traffic and therefore must maintain a consistently high standard of performance. However, performance can be negatively affected by factors such as workload and fatigue, potentially leading to performance decline and performance-related incidents. Real-time identification of negative influences would facilitate timely implementation of supportive strategies prior to performance decline. The current study aimed to explore the concept of ‘behavioral indicators’ to identify when a controller was reaching a performance limit. A second aim was to capture behavioral indicators associated with performance influencing factors. A total of 65 controllers spanning Tower, Approach and Enroute facilities across the United States of America were interviewed. Findings revealed that controllers were familiar with the concept of behavioral indicators, and that indicators were associated with specific performance-influencing factors. Implications for implementing behavioral indicators training in control environments are discussed.

air traffic control↗
NASA NTRSDate not supplied

Behavioral Indicators: How You Know When You are Losing the Flick and What to Do About It?

Air traffic controllers are responsible for the safety and efficiency of air traffic and therefore must maintain a consistently high standard of performance. However, performance can be negatively affected by factors such as workload and fatigue, potentially leading to performance decline and performance-related incidents. Real-time identification of negative influences would facilitate timely implementation of supportive strategies prior to performance decline. The current study aimed to explore the concept of ‘behavioral indicators’ to identify when a controller was reaching a performance limit. A second aim was to capture behavioral indicators associated with performance influencing factors. A total of 65 controllers spanning Tower, Approach and Enroute facilities across the United States of America were interviewed. Findings revealed that controllers were familiar with the concept of behavioral indicators, and that indicators were associated with specific performance-influencing factors. Implications for implementing behavioral indicators training in control environments are discussed.

behavioral indicators↗
NASA NTRSDate not supplied

Behavioral Indicators in Air Traffic Controllers: How Do You Know When You Are Working at The Edge of Performance?

Air traffic controllers are responsible for the safety and efficiency of air traffic and therefore must maintain a consistently high standard of performance. However, performance can be negatively affected by factors such as workload and fatigue, potentially leading to performance decline and performance-related incidents. Real-time identification of negative influences would facilitate timely implementation of supportive strategies prior to performance decline. The current study aimed to explore the concept of ‘behavioral indicators’ to identify when a controller was reaching a performance limit. A second aim was to capture behavioral indicators associated with performance influencing factors. A total of 65 controllers spanning Tower, Approach and Enroute facilities across the United States of America were interviewed. Findings revealed that controllers were familiar with the concept of behavioral indicators, and that indicators were associated with specific performance-influencing factors. Implications for implementing behavioral indicators training in control environments are discussed.

behavioral indicators↗
NASA NTRSDate not supplied

Behavioral Medicine Risks and Mitigations in Isolated, Confined, and Extreme Environments

Human spaceflight beyond low Earth orbit will present unique environmental challenges to astronauts’ operational performance and well-being. Crews will need to work and live in confined and hazardous environments for prolonged missions that involve variable workloads and limitations to privacy, food options, exercise capabilities, leisure outlets, and communication with ground support personnel and loved ones. Currently, behavioral and cognitive risks of spaceflight are mitigated by selecting exceptionally resilient crews and providing extensive individual and team skills training pre-mission, as well as in-mission crew support via a suite of countermeasures targeting sleep and performance optimization, stress management, family support, and team cohesion. However, current countermeasures are difficult or impossible to implement in long-distance exploration as they require real-time communication with Earth and routine resupply. New countermeasure approaches are needed to adapt and enhance the current complement for the new challenges ahead. NASA therefore conducts research at ground-based spaceflight analogs to aid in characterizing the behavioral and cognitive risks of living and working in isolated, confined, and extreme (ICE) operational environments. Antarctic research stations are among the few long-duration ICE analogs in existence and are therefore uniquely positioned to support behavioral medicine research to enable human exploration beyond Earth. In this review, we will discuss previous and ongoing efforts to better understand spaceflight behavioral medicine risks, as well as validate new countermeasure approaches for future missions to the moon and Mars.

Behavioral Health↗
DOE OSTI2022

Behavioral and neuroinflammatory changes caused by glyphosate: Base herbicide in mice offspring

Abstract Background Glyphosate is a pesticide considered of low toxicity, but scientific evidences show it can be harmful to health. This study aimed to evaluate the toxicity in mice offspring exposed to glyphosate‐based herbicide (GBH) during the intrauterine period. Methods Female matrices received glyphosate 0.3 mg/kg daily per oral throughout the gestational period, which was variable between 18 and 22 days. From the 25th until the 28th days post‐birth, mice offspring were subjected to behavioral tests, and the prefrontal cortex was processed for immunohistochemical analysis. Results Two significant behavioral changes were observed: anxiety in the GLIF0.3 group, increase in the behavior burying marbles in the marble‐burying test and hyperactivity, expressed by the significant increase of the crossing number in the open field test. The increased microglia, TNF‐alpha, and astrocyte expression were also observed in the prefrontal cortex of offspring treated with GLIF0.3. Conclusion Exposure to GBH during mice intrauterine development induces hyperactive and anxious behavior, evidencing neuroinflammation.

de Castro Vieira Carneiro, Carla Larissa↗
DOE OSTI2022

Resident and transient coyotes exhibit differential patterns of movement behavior across heterogeneous landscapes in the southeastern United States

Coyotes (Canis latrans) are a highly adaptable canid species whose behavioral plasticity has allowed them to persist in a wide array of habitats throughout North America. As generalists, coyotes can alter movement patterns and change territorial strategies between residency (high site fidelity) and transiency (low site fidelity) to maximize fitness. Uncertainty remains about resident and transient coyote movement patterns and habitat use because research has reached conflicting conclusions regarding patterns of habitat use by both groups. We quantified effects of habitat on resident and transient coyote movement behavior using first passage time (FPT) analysis, which assesses recursive movement along an individual's movement path to delineate where they exhibit area-restricted search (ARS) behaviors relative to habitat attributes. We quantified monthly movement rates for 171 coyotes (76 residents and 53 transients) and then used estimated FPT values in generalized linear mixed models to quantify monthly habitat use for resident and transient coyotes. Transients had greater movement rates than residents across all months except January. Resident FPT values were positively correlated with agricultural land cover during fall and winter, but negatively correlated with agriculture during spring. Resident FPT values were also negatively correlated with developed habitats during May–August, deciduous land cover during June–August, and wetlands during September–January except November. FPT values of transient coyotes were positively correlated with developed areas throughout much of the year and near wetlands during July–September. Transient FPT values were negatively correlated with agriculture during all months except June and July. High FPT values (ARS behavior) of residents and transients were generally correlated with greater densities of edge habitat. Although we observed high individual variation in space use, our study found substantive differences in habitat use between residents and transients, providing further evidence that complexity and plasticity of coyote habitat use is influenced by territorial strategy.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Chemostatic behavior of major ions and contaminants in a semiarid spring and stream system near Los Alamos, NM, USA

Recent studies have focused on the relationship between solute concentrations and discharge in streams, demonstrating that concentrations can vary little relative to changes in discharge (chemostatic behavior). Chemostatic behavior is dependent on catchment characteristics (e.g., lithology, geomorphology, and vegetation) and chemical characteristics of the solute (e.g., availability, reactivity, and mobility). An investigation of three springs and a stream near Los Alamos, New Mexico, USA, reveals that springs can behave in a chemostatic fashion as stream systems tend to do. Another unique finding of this study is that the anthropogenic contaminants barium and the high explosive RDX (hexahydro-1,3,5- trinitro-1,3,5-triazine) can also behave chemostatically. The chemostatic behavior of a contaminant has important implications for the residence time of contaminants in a system as well as having a major control on contaminant flux and mass transport. Redox (reductionoxidation) and biogeochemically sensitive analytes (e.g., Fe, SO 4 , & NO 3 ) display a combination of chemostatic and chemodynamic behavior, showing the influence of temporally variable conditions on stream and springs chemistries.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

A constitutive structural parameter c b for the work hardening behavior of additively manufactured Ti-6Al-4V

The mechanical behavior of Ti-6Al-4V produced by additive manufacturing processes is assessed as based on a model derived from the Kocks–Mecking relationship. A constitutive parameter c b is derived from a linear Kocks–Mecking relationship for the microstructure that is characteristic of the work hardening behavior. The formulation for c b is determined by considering the plastic strain between the strengths at the proportional limit and the plastic instability. In this way, the model accommodates the variation in work hardening behavior observed when evaluating material as produced and tested along different orientations. The modeling approach is presented and evaluated for the case of Ti-6Al-4V additively manufactured materials as tested under quasi-static uniaxial tension. It is found that different test specimen orientations, along with postbuild heat treatments, produce a change in the microstructure and plasticity behavior which can be accounted for in the corresponding change of the c b values.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Automated Experiments of Local Non–Linear Behavior in Ferroelectric Materials

An automated experiment in multimodal imaging to probe structural, chemical, and functional behaviors in complex materials and elucidate the dominant physical mechanisms that control device function is developed and implemented. Here, the emergence of non-linear electromechanical responses in piezoresponse force microscopy (PFM) is explored. Non-linear responses in PFM can originate from multiple mechanisms, including intrinsic material responses often controlled by domain structure, surface topography that affects the mechanical phenomena at the tip-surface junction, and the presence of surface contaminants. Using an automated experiment to probe the origins of non-linear behavior in ferroelectric lead titanate (PTO) and ferroelectric Al 0.93 B 0.07 N films, it is found that PTO shows asymmetric nonlinear behavior across a/c domain walls and a broadened high nonlinear response region around c/c domain walls. In contrast, for Al 0.93 B 0.07 N, well-poled regions show high linear piezoelectric responses, when paired with low non-linear responses regions that are multidomain show low linear responses and high nonlinear responses. It is shown that formulating dissimilar exploration strategies in deep kernel learning as alternative hypotheses allows for establishing the preponderant physical mechanisms behind the non-linear behaviors, suggesting that automated experiments can potentially discern between competing physical mechanisms. Furthermore, this technique can also be extended to electron, probe, and chemical imaging.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Influence of the Rheology Behavior of Water-Soluble Polyacrylamides and Their Efficiency of Flocculation

Organic polymers such as water-soluble polyacrylamides that are used as flocculants in solid–liquid separations, have their flocculation efficiency determined by the behavior of their macromolecules in solution. This behavior is affected by its intrinsic characteristics, especially the presence of ionic groups in its macromolecules. In this context, the present work aimed to characterize three water-soluble polyacrylamides. The effect of the intrinsic properties of each polymer on the behavior of the polymer chains in aqueous solution was compared in different environments. Beside this, the polymers behavior effect on the destabilization of particles was evaluated through kaolin particle aggregation studies. Viscosity results show that the conformation of the macromolecules in solution is altered according to the amount of ionized groups present. This variation, together with other factors such as the affinity with the kaolin particles and the excess of ions in solution, reflects in the flocculation efficiency of kaolin particles, in the flocs size and the flocs sedimentation rate. Graphic Abstract: .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗