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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Use of multiscale zirconium alloy deformation models in nuclear fuel behavior analysis

Accurate prediction of cladding mechanical behavior is a key aspect of modeling nuclear fuel behavior, especially for conditions of pellet-cladding interaction (PCI), reactivity-initiated accidents (RIA), and loss of coolant accidents (LOCA). Current approaches to fuel performance modeling rely on empirical constitutive models for cladding creep, growth and plastic deformation, which are limited to the materials and conditions for which the models were developed. To improve upon this approach, a microstructurally-based zirconium alloy mechanical deformation analysis capability is being developed within the United States Department of Energy Consortium for Advanced Simulation of Light Water Reactors (CASL). Specifically, the viscoplastic self-consistent (VPSC) polycrystal plasticity modeling approach, developed by Lebensohn and Tomé [1], has been coupled with the BISON engineering scale fuel performance code to represent the mechanistic material processes controlling the deformation behavior of light water reactor (LWR) cladding. A critical component of VPSC is the representation of the crystallographic nature (defect and dislocation movement) and orientation of the grains within the matrix material and the ability to account for the role of texture on deformation. A future goal is for VPSC to obtain information on reaction rate kinetics from atomistic calculations to inform the defect and dislocation behavior models described in VPSC. The multiscale modeling of cladding deformation mechanisms allowed by VPSC far exceed the functionality of typical semi-empirical constitutive models employed in nuclear fuel behavior codes to model irradiation growth and creep, thermal creep, or plasticity. This paper describes the implementation of an interface between VPSC and BISON and provides initial results utilizing the coupled functionality.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Behavior of the maximum likelihood in quantum state tomography

Quantum state tomography on a d-dimensional system demands resources that grow rapidly with d. They may be reduced by using model selection to tailor the number of parameters in the model (i.e., the size of the density matrix). Most model selection methods typically rely on a test statistic and a null theory that describes its behavior when two models are equally good. Here, we consider the loglikelihood ratio. Because of the positivity constraint ρ ≥ 0, quantum state space does not generally satisfy local asymptotic normality (LAN), meaning the classical null theory for the loglikelihood ratio (the Wilks theorem) should not be used. Thus, understanding and quantifying how positivity affects the null behavior of this test statistic is necessary for its use in model selection for state tomography. We define a new generalization of LAN, metric-projected LAN, show that quantum state space satisfies it, and derive a replacement for the Wilks theorem. In addition to enabling reliable model selection, our results shed more light on the qualitative effects of the positivity constraint on state tomography.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Leaching Behavior of Rare Earth Elements in Fort Union Lignite Coals of North America

Rare earth elements are crucial materials in an incredible array of consumer goods, energy system components and military defense applications. However, the global production and entire value chain for rare earth elements is dominated by China, with the U.S. currently 100% import reliant for these critical materials. Traditional mineral ores including those previously mined in the U.S., however, have several challenges. Chief among these is that the content of the most critical and valuable of the rare earths are deficient, making mining uneconomical. Further, the supply of these most critical rare earths is nearly 100% produced in China from a single resource that is only projected to last another 10 to 20 years. The U.S. currently considers the rare earths market an issue of national security. It is imperative that alternative domestic sources of rare earths be identified and methods developed to produce them. Recently, coal and coal byproducts have been identified as one of these promising alternative resources. This paper details the results of a study on characterization of North Dakota lignite and lignite-related feedstocks as an assessment of their feasibility for rare earth element recovery. The abundance, distribution and modes of occurrence of the rare earth elements in the samples collected were determined in this initial study to inform the selection of appropriate extraction and concentration methods to recover the rare earth elements. Materials investigated include the lignite coals, clay-rich sediments associated with the coal seams, and materials associated with a lignite beneficiation system and power plant. The results show that high rare earth element levels exist both in lignite coals and associated sediments. The form of the rare earth elements in the clay materials is primarily as ultra-fine mineral grains. In the lignite coals, approximately 80-95% of the rare earths content is organically associated, primarily as coordination complexes.

Laudal, Daniel A.↗
DOE OSTI2018

Aqueous aggregation behavior of citric acid coated magnetite nanoparticles: Effects of pH, cations, anions, and humic acid

Highlights: • Citric acid (CA) coatings greatly enhanced the stability of MNPs at pH = 5–9. • Stability of CA-MNPs increased with pH increase due to CA deprotonation. • The valence and adsorption of ions affected the surface charge of CA-MNPs. • The aggregation behaviors of CA-MNPs agreed with DLVO predictions. Improving the colloidal stability of magnetite nanoparticles (MNPs) is essential for their successful applications. In this study, the surface zeta potential and particle size evolutions of citric acid coated magnetite nanoparticles (CA-MNPs) were measured under varied aqueous conditions using dynamic light scattering (DLS). The effects of pH (5.0–9.0), ionic strength (IS), cations (Na{sup +} and Ca{sup 2+}), anions (phosphate, sulfate, and chloride) and humic acid on the aggregation behaviors of CA-MNPs were explored. Compared with bare MNPs, the stability of CA-MNPs were greatly improved over the typical pH range of natural aquatic environments (pH = 5.0–9.0), as the coated CA-MNPs were highly negatively charged over the pH range due to the low pK{sub a1} value (3.13) of citrate acid. CA-MNPs were more stable in the presence of monovalent cation (Na{sup +}) compared with divalent cation (Ca{sup 2+}), as Ca{sup 2+} could neutralize the surface charge of MNPs more significantly than Na{sup +}. In the presence of anions, the surface charges of CA-MNPs became more negative, and the stability of CA-MNPs followed the order: in phosphate > sulfate > chloride. The observed aggregation trend could be explained by the differences in the valences of the anions and their adsorption behaviors onto CA-MNPs, which altered the surface charges of CA-MNPs. The measured critical coagulation concentrations (CCC) values of CA-MNPs in these electrolyte solutions agreed well with Derjaguin–Landau–Verwey–Overbeek (DLVO) calculations. With the addition of Humic acid (HA), the aggregation of CA-MNPs was inhibited in all electrolyte solutions even with the critical coagulation concentrations. This is due to the adsorption of HA onto CA-MNPs, which enhanced the electrostatic and steric repulsive forces between CA-MNPs. Considering the good stability of CA-MNPs in solutions with varied pH and electrolyte compositions, as well as with the easy synthesis of CA-MNPs and their non-toxicity, this study suggested CA coating as a good strategy to increase the stability of MNPs.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Incubation temperature influences the behavioral traits of a young precocial bird

Abstract The environment in which animals develop can have important consequences for their phenotype. In reptiles, incubation temperature is a critical aspect of the early developmental environment. Incubation temperature influences morphology, physiology, and behavior of non‐avian reptiles, however, little is known about how incubation temperature influences offspring phenotype and behaviors important to avian survival. To investigate whether incubation temperature influences avian behaviors, we collected wood duck ( Aix sponsa ) eggs from the field and incubated them at three naturally occurring incubation temperatures (35.0, 35.8, and 37.0°C). We conducted multiple repeated behavioral trials on individual ducklings between 5 and 15 days post‐hatch to assess activity, exploratory, and boldness behaviors, classified along a proactive‐reactive continuum. We measured growth rates and circulating levels of baseline and stress‐induced corticosterone levels to investigate possible physiological correlates of behavior. Ducklings incubated at the lowest temperature displayed more proactive behaviors than those incubated at the two higher temperatures. We also found that younger ducklings exhibited more proactive behavior than older ducklings and males exhibited more proactive behavior than females. Further, duckling behaviors were repeatable across time and contexts, indicative of a proactive–reactive continuum of behavioral tendencies. However, neither corticosterone levels nor growth rates were related to behavior. This provides some of the first evidence that incubation temperature, a critical parental effect, influences avian offspring behaviors that may be important for survival. Our results identify incubation temperature as a mechanism that contributes to the development of behavioral traits and, in part, explains how multiple behavioral types may be maintained within populations.

Hope, Sydney F.↗
DOE OSTI2018

Understanding scale-dependent soft-error behavior of scientific applications

Analyzing application fault behavior on large-scale systems is time-consuming and resource-demanding. Currently, researchers need to perform fault injection campaigns at full scale to understand the effects of soft errors on applications and whether these faults result in silent data corruption. Both time and resource requirements greatly limit the scope of the resilience studies that can be currently performed. In this work, we propose a methodology to model application fault behavior at large scale based on a reduced set of experiments performed at small scale. We employ machine learning techniques to accurately model application fault behavior using a set of experiments that can be executed in parallel at small scale. Our methodology drastically reduces the set and the scale of the fault injection experiments to be performed and provides a validated methodology to study application fault behavior at large scale. We show that our methodology can accurately model application fault behavior at large scale by using only small scale experiments. In some cases, we can model the fault behavior of a parallel application running on 4,096 cores with about 90% accuracy based on experiments on a single core.

Kestor, Gokcen G.↗
NASA NTRS2017

Mouse Behavior on ISS: The Emergence of a Distinctive, Organized Group Circling Behavior Unique to Spaceflight

As interest in long duration effects of space habitation increases, understanding the behavior of model organisms living within the habitats engineered to fly them is vital for designing, validating, and interpreting future spaceflight studies. Only a handful of papers have previously reported behavior of mice and rats in the weightless environment of space (Andreev-Andrievskiy, et al., 2013; Cancedda et al., 2012; Ronca et al., 2008). The Rodent Research Hardware and Operations Validation Mission (Rodent Research-1; RR1) utilized the Rodent Habitat (RH) developed at NASA Ames Research Center to fly mice on the ISS. Ten adult (16-week-old) female C57BL6J mice were launched on September 21st, 2014 in an unmanned Dragon Capsule, and spent 37 days in flight. Here we report group behavioral phenotypes of the RR1 Flight (FLT) and environment-matched Ground Control (GC) mice in the RH during this long duration flight. Video was recorded for 34 days on the ISS, permitting daily assessments of overall health and well being of the mice, and providing a valuable repository for detailed behavioral analysis. As compared to GC mice, RR1 FLT mice exhibited the same range of behaviors, including eating, drinking, exploration, self- and allogrooming, and social interactions at similar or greater levels of occurrence. Overall activity was greater in FLT as compared to GC mice, with spontaneous ambulatory behavior, including organized circling or race-tracking behavior that emerged within the first few days of flight following a common developmental sequence, comprising the primary dark cycle activity of FLT mice. Circling participation by individual mice persisted throughout the mission. Analysis of group behavior over mission days revealed recruitment of mice into the group phenotype, coupled with decreasing numbers of collisions between circling mice. This analysis provides insights into the behavior of mice in microgravity, and clear evidence for the emergence of a distinctive, organized group behavior unique to the weightless space environment. Supported by the NASA Rodent Research Project, Space Biology Program, and Space Life Sciences Training Program.

spaceflight↗
NASA NTRS2017

Mouse Behavior on ISS: The Emergence of Distinctive, Organized Group Circling Behavior Unique to Spaceflight

As interest in long duration effects of space habitation increases, understanding the behavior of model organisms living within the habitats engineered to fly them is vital for designing, validating, and interpreting future spaceflight studies. Only a handful of papers have previously reported behavior of mice and rats in the weightless environment of space (Andreev-Andrievskiy, et al., 2013; Cancedda et al., 2012; Ronca et al., 2008). The Rodent Research Hardware and Operations Validation Mission (Rodent Research-1; RR1) utilized the Rodent Habitat (RH) developed at NASA Ames Research Center to fly mice on the ISS. Ten adult (16-week-old) female C57BL6J mice were launched on September 21st, 2014 in an unmanned Dragon Capsule, and spent 37 days in flight. Here we report group behavioral phenotypes of the RR1 Flight (FLT) and environment-matched Ground Control (GC) mice in the RH during this long duration flight. Video was recorded for 34 days on the ISS, permitting daily assessments of overall health and well being of the mice, and providing a valuable repository for detailed behavioral analysis. As compared to GC mice, RR1 FLT mice exhibited the same range of behaviors, including eating, drinking, exploration, self- and allogrooming,and social interactions at similar or greater levels of occurrence. Overallactivity was greater in FLT as compared to GC mice, with spontaneous ambulatory behavior, including organized circling or race-tracking behavior that emerged within thefirst few days of flight following a common developmental sequence, comprising theprimary dark cycle activity of FLT mice. Circling participation by individual micepersisted throughout the mission. Analysis of group behavior over mission days revealed recruitment of mice into the group phenotype, coupled with decreasing numbers of collisions between circling mice. This analysis provides insights into the behavior of mice in microgravity, and clear evidence for the emergence of a distinctive,organized group behavior unique to the weightless space environment.

mice↗
DOE OSTI2024

Individual low-carbon behaviors and influencing factors: Insights from a behavior survey study in China

Climate change is a major global concern. Greenhouse gas emissions that cause global climate change are directly or indirectly affected by human activities. Individual low-carbon behaviors are crucial in reducing CO 2 emissions and improving environmental and ecological health. To effectively promote individual low-carbon behavior, this study designed a questionnaire on the factors influencing individual low-carbon intentions and behavior based on theoretical models of environmental behavior. A total of 2430 valid questionnaires were collected in China. This study focuses on analyzing the impact of demographic characteristics, internal and external factors on individual low-carbon behaviors and their interrelationships. The research shows correlations between internal and external factors in determining low-carbon intention or behaviors. Internal factors-related low-carbon behavior is not closely linked with demographic variables, whereas the external factors-related low-carbon behavior vary significantly by age, residence, education, marital status, occupation, and income. The findings have important implications for designing effective policies to promote low-carbon behaviors, such as creating a more favorable external environment and increasing the use of policy tools for reducing CO 2 emission.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Self-reported health behaviors, including sleep, correlate with doctor-informed medical conditions: data from the 2011 Health Related Behaviors Survey of U.S. Active Duty Military Personnel

Health behaviors and cardiometabolic disease risk factors may differ between military and civilian populations; therefore, in U.S. active duty military personnel, we assessed relationships between demographic characteristics, self-reported health behaviors, and doctor-informed medical conditions. Methods Data were self-reported by 27,034 active duty military and Coast Guard personnel who responded to the 2011 Department of Defense Health Related Behaviors Survey. Multivariate linear and logistic regressions were used to estimate cross-sectional associations between (1) demographic characteristics (age, sex, service branch, marital status, children, race/ethnicity, pay grade) and self-reported behaviors (exercise, diet, smoking, alcohol, sleep); (2) demographic characteristics and doctor-informed medical conditions (hypertension, hypercholesterolemia, low high density lipoprotein (HDL) cholesterol, hyperglycemia) and overweight/obesity; and (3) behaviors and doctor-informed medical conditions. Results Among respondents (age 29.9 ± 0.1 years, 14.7% female), females reported higher intake than men of fruit, vegetables, and dairy; those with higher education reported higher intakes of whole grains; those currently married and/or residing with children reported higher intake of starches. Older age and female sex were associated with higher odds (ORs 1.25 to 12.54 versus the youngest age group) of overweight/obesity. Older age and female sex were also associated with lower odds (ORs 0.29 to 0.65 versus male sex) of doctor-informed medical conditions, except for blood glucose, for which females had higher odds. Those currently married had higher odds of high cholesterol and overweight/obesity, and separated/divorced/widowed respondents had higher odds of high blood pressure and high cholesterol. Short sleep duration (< 5 versus 7–8 h/night) was associated with higher odds (ORs 1.36to 2.22) of any given doctor-informed medical condition. Strength training was associated with lower probability of high cholesterol, high triglycerides, and low HDL, and higher probability of overweight/obesity. Dietary factors were variably associated with doctor-informed medical conditions and overweight/obesity. Conclusions This study observed pronounced associations between health behaviors—especially sleep—and medical conditions, thus adding to evidence that sleep is a critical, potentially modifiable behavior within this population. When possible, adequate sleep should continue to be promoted as an important part of overall health and wellness throughout the military community.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Hydrogen bond effects on compressional behavior of isotypic minerals: high-pressure polymorphism of cristobalite-like Be(OH) 2

Three isotypic crystals, SiO 2 (α-cristobalite), ε-Zn(OH) 2 (wülfingite), and Be(OH) 2 (β-behoite), with topologically identical frameworks of corner-connected tetrahedra, undergo displacive compression-driven phase transitions at similar pressures (1.5–2.0 GPa), but each transition is characterized by a different mechanism resulting in different structural modifications. In this study, we report the crystal structure of the high-pressure γ-phase of beryllium hydroxide and compare it with the high-pressure structures of the other two minerals. In Be(OH) 2 , the transition from the ambient β-behoite phase with the orthorhombic space group P2 1 2 1 2 1 and ambient unit cell parameters a = 4.5403(4) Å, b = 4.6253(5) Å, c = 7.0599(7) Å, to the high-pressure orthorhombic γ-polymorph with space group Fdd2 and unit cell parameters (at 5.3(1) GPa) a = 5.738(2) Å, b = 6.260(3) Å, c = 7.200(4) Å takes place between 1.7 and 3.6 GPa. This transition is essentially second order, is accompanied by a negligible volume discontinuity, and exhibits both displacive and reversible character. The mechanism of the phase transition results in a change to the hydrogen bond connectivities and rotation of the BeO 4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Oxygen-storage behavior and local structure in Ti-substituted YMnO{sub 3}

Hexagonal manganates RMnO{sub 3} (R=Y, Ho, Dy) have been recently shown to exhibit oxygen-storage capacities promising for three-way catalysts, air-separation, and related technologies. Here, we demonstrate that Ti substitution for Mn can be used to chemically tune the oxygen-breathing properties of these materials towards practical applications. Specifically, Y(Mn{sub 1−x}Ti{sub x})O{sub 3} solid solutions exhibit facile oxygen absorption/desorption via reversible Ti{sup 3+}↔Ti{sup 4+} and Mn{sup 3+}↔Mn{sup 4+} reactions already in ambient air at ≈400 °C and ≈250 °C, respectively. On cooling, the oxidation of both cations is accompanied by oxygen uptake yielding a formula YMn{sup 3+}{sub 1−x-y}Mn{sup 4+}{sub y}Ti{sup 4+}{sub x}O{sub 3+δ}. The presence of Ti promotes the oxidation of Mn{sup 3+} to Mn{sup 4+}, which is almost negligible for YMnO{sub 3} in air, thereby increasing the uptake of oxygen beyond that required for a given Ti{sup 4+} concentration. The reversibility of the redox reactions is limited by sluggish kinetics; however, the oxidation process continues, if slowly, even at room temperature. The extra oxygen atoms are accommodated by the large interstices within a triangular lattice formed by the [MnO{sub 5}] trigonal bipyramids. According to bond distances from Rietveld refinements using the neutron diffraction data, the YMnO{sub 3} structure features under-bonded Mn and even more severely under-bonded oxygen atoms that form the trigonal bases of the [MnO{sub 5}] bipyramids. The tensile bond strain around the 5-fold coordinated Mn site and the strong preference of Ti{sup 4+}(and Mn{sup 4+}) for higher coordination numbers likely provide driving forces for the oxidation reaction. Reverse Monte Carlo refinements of the local atomic displacements using neutron total scattering revealed how the excess oxygen atoms are accommodated in the structure by correlated local displacements of the host atoms. Large displacements of the under-bonded host oxygen atoms play a key part in this lattice-relaxation process, facilitating reversible exchange of significant amounts of oxygen with atmosphere. - Graphical abstract: Concurrent redox reactions involving Ti and Mn yield facile absorption/desorption of excess oxygen. - Highlights: • Concurrent redox reactions involving Ti and Mn yield oxygen absorption/desorption. • Excess oxygen is accommodated as interstitials via correlated atomic shifts. • Oxygen breathing is facilitated by the under-bonding of host Mn and O atoms.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗