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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Effect of Cobalt Oxide Nanoparticles on the Nano-scale Free Volume and Optical Properties of Biodegradable CMC/PVA Films

Chemically prepared cobalt oxide nanoparticles (NPs) were added to biodegradable carboxymethyl cellulose (CMC) (20%)/polyvinyl alcohol (PVA) (80%) blend films. The structural properties of these films were investigated by X-ray diffraction, Fourier transformation infrared spectroscopy (FTIR) and differential thermal analysis (DTA). Co{sub 3}O{sub 4}/(CMC + PVA) films show a semi-crystalline structure and the degree of crystallinity decreases with adding Co{sub 3}O{sub 4} NPs. FTIR confirms the good interaction between the blend chains and Co{sub 3}O{sub 4} NPs. The melting temperature T{sub m} for CMC/PVA is about 212 °C then decreased with increasing Co{sub 3}O{sub 4} content, due to some decrease in the ordered association of the blend which results in a decrease in the blend crystallinity. Positron annihilation lifetime spectroscopy (PALS) measurements were carried out with a conventional fast–fast coincidence spectrometer. It was found that ortho-positronium lifetime τ{sub 3} and free volume V{sub f} increase while o-Ps intensity I{sub 3} still constant as Co{sub 3}O{sub 4} concentration increases. This is because adding Co{sub 3}O{sub 4} NPs encourages the formation of o-Ps. The swelling ratio SR% as a function of Co{sub 3}O{sub 4} concentration was also studied and its value increases with Co{sub 3}O{sub 4} addition. The optical study illustrated the decrease of the transmittance T of the films from 87 to 35.5% with increasing Co{sub 3}O{sub 4} content from 0 to 0.9 wt%. Also, both the direct and indirect optical band gaps of the films red-shifted from 4.05 to 3.75 eV and 3.3 to 2.75 eV, respectively. The influence of Co{sub 3}O{sub 4} on the refractive index of the films is also reported.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Suppression of NF-κB activation by PDLIM2 restrains hepatic lipogenesis and inflammation in high fat diet induced mice

Highlights: • PDLIM2 deficiency promotes HFD-induced mice obesity and insulin resistance. • PDLIM2 deficiency promotes hepatic dyslipidemia in HFD-induced mice. • PDLIM2 deficiency intensifies HFD-induced hepatic inflammation. • Reducing NF-κB activation attenuates PDLIM2 deficiency-exacerbated inflammation and dyslipidemia in PAL-treated primary hepatocytes. Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis, insulin resistance, dyslipidemia and a systemic pro-inflammatory response, a leading cause of cirrhosis and hepatocellular carcinoma. Here, we showed that PDZ-LIM domain-containing protein 2 (PDLIM2) was an effective suppressor of steatohepatitis. After 16 weeks on a high fat diet (HFD), obesity, insulin resistance, hepatic dyslipidemia and inflammation were markedly aggravated in PDLIM2-knockout (KO) mice. PDLIM2 deletion resulted in lipid accumulation in liver tissue samples of HFD-induced mice, as evidenced by the significant increase of hepatic TG and TC through reducing the expression of lipogenesis- and transcriptional regulators of lipid metabolism-related genes and enhancing fatty acid oxidation-associated molecules. In addition, PDLIM2-ablation promoted the expression of pro-inflammatory cytokines by activating nuclear factor kappa-B (NF-κB) signaling pathway, as supported by the remarkable increase of phosphorylated IKKβ, IκBα and NF-κB expressions in liver of HFD-fed mice. Of note, the in vitro study demonstrated that PDLIM2 ablation-enhanced inflammatory response and disorder of lipid metabolism were abrogated by suppressing NF-κB activity. Collectively, the findings could lead to the development of potential therapeutic strategy to prevent NAFLD and associated metabolic disorders by targeting PDLIM2.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Suppressing Irf2bp2 expressions accelerates metabolic syndrome-associated brain injury and hepatic dyslipidemia

Highlights: • Irf2bp2 deletion promotes HFD-induced metabolic syndrome and cognitive dysfunction in mice. • Irf2bp2 knockout aggravates brain injury in HFD-fed mice. • Irf2bp2 ablation alleviates oxidative stress and inflammation in brain of HFD-fed mice. • Suppressing Irf2bp2 expressions exacerbate inflammatory response in PAL- or LPS-treated BV2 cells. Increasing studies indicate that high fat diet (HFD) induces neuroinflammation in animal models with obesity, yet the pathology of it is unclear. Interferon Regulatory Factor 2 Binding Protein 2 (Irf2bp2) is a key regulator of macrophage polarization, playing an essential role in regulating inflammatory response. This study investigated the effects of Irf2bp2 on HFD-induced brain injury, and explored the possible molecular mechanisms using wild type (WT) and Irf2bp2 knockout (KO) mice. The results indicated that HFD-increased body weight of mice was further elevated by Irf2bp2-knockout. In addition, Irf2bp2-deletion accelerated HFD-induced metabolic syndrome, as evidenced by the promoted fasting glucose and insulin levels. In the results of behavioral measurements, Irf2bp2-knockout intensified cognitive deficit in HFD-fed mice by using Y-maze, passive avoidance, and morris water maze (MWM) tests. Further, Irf2bp2-deficiency accelerated the activation of astrocytes and microglia cells, as evidenced by the promoted expressions of glial fibrillary acidic protein (GFAP) and Iba-1 in hippocampus and hypothalamus of HFD-fed mice. HFD for 16 weeks induced oxidative stress in serum and brain of mice, as proved by the up-regulated malondialdehyde (MDA) levels and down-regulated superoxide dismutase (SOD) activity, which were significantly enhanced due to Irf2bp2 knockout. Moreover, HFD-triggered systematic and central nervous inflammation by increasing the release of interleukin 1β (IL-1β) and tumor necrosis factor (TNF)-α, accompanied with elevated p-nuclear factor-κB (NF-κB) expressions. Notably, HFD-induced inflammation was significantly exacerbated by Irf2bp2 deletion. Intriguingly, HFD-induced dyslipidemia in liver of mice was further aggravated by Irf2bp2 suppression. Our in vitro results verified the effects of Irf2bp2-inhibition on the promotion of inflammatory response in BV2 cells and lipid dysfunction in primary hepatocytes. Therefore, the findings above suggested that inhibiting Irf2bp2 expression provided a potential therapeutic approach for the prevention of metabolic syndrome-associated central nervous injury.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Evaluation of adsorption and mechanical strength of 13X zeolite mixtures with phyllosilicate binders using molecular dynamics simulation and positron annihilation spectroscopy

There is growing interest in developing zeolites with novel internal structures that have optimal adsorptive capacity and high mechanical strength, while offering advantages, such as being light weight. We integrate computational and experimental methods to explore the effect of binder/zeolite types, and weight percentages on the mechanical strength of 13X zeolite and adsorption capacities of N 2 , H 2 O, and CO 2 for additive manufacturing (AM) applications with the goal of maximizing both adsorption and strength. Zeolite 13X mixtures and phyllosilicate binders (either bentonite or kaolin) are combined using molecular dynamics (MD) simulations to create structures with various binder/zeolite weight percentages. Further, adsorption capabilities and mechanical strength are assessed using the grand canonical Monte Carlo (GCMC) and ReaxFF modules, respectively. Our modeling shows that an optimized zeolite/binder ratio for N 2 adsorption is around 15 wt% for kaolin and roughly 10 wt% for bentonite. The resulting parameters can be applied to facilitate macro-scale computational fluid dynamics (CFD) and finite element method (FEM) simulations of an AM zeolite structure. We also performed Positron Annihilation Lifetime Spectroscopy (PALS) measurements on zeolite samples to explore the effect of changes in the internal volume. The results show an inverse relationship between the free volume and the solid loading and adding a binder changes the morphology of the zeolite-binder compound and decreases open-volume area significantly.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Palliative Radiation Therapy for Advanced Head and Neck Carcinomas: A Phase 2 Study

Purpose: Incurable head and neck cancer is hard to manage with usual palliative care. Radiation therapy (RT) in this setting is sometimes omitted because there is an apprehension that the side effects in the head and neck region might counterbalance the benefits. The objective of this phase 2 study was to evaluate whether highly conformal RT could improve the therapeutic ratio with this comprehensive Quality of Life (QOL) and toxicity evaluation. Methods and Materials: Patients from 2 academic centers, deemed unfit for radical treatment because of their poor medical condition or advanced cancer stage by an experienced tumor board, were offered 25 Gy in 5 daily intensity modulated RT fractions over 1 week to the symptomatic tumor volume. QOL was evaluated with the European Organization for Research and Treatment of Cancer QLQ-C15-PAL and QLQ-H&N35 questionnaires, and toxicities with the Common Terminology Criteria for Adverse Events version 4.0. Survival and time to tumor progression were calculated with the Kaplan-Meier method. Results: Thirty-two patients were recruited, of whom 66% had at least T4, N3, or M1 disease. The QOL questionnaires completion rate was 86%. Eighty-eight percent of patients received the planned dose. The median overall survival and progression-free survival times were, respectively, 6.5 and 3.2 months. No grade 4 or 5 toxicity was seen. Only 13% of patients had any grade 3 toxicities, and 17% of patients reported no toxicity at all. The QOL was equal or improved, and head and neck symptoms remained equal to or lower than the baseline values for most patients at up to 6 months. Eighty-five percent of patients would have chosen to receive this RT regimen again when asked. Conclusions: This palliative RT regimen was highly tolerable and effective in preserving or improving self-reported QOL in most patients for up to 6 months, which corresponds to this population's median overall survival. Given the minimal side effects, intensification could be considered to achieve longer locoregional control.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Effects of quench rate and natural ageing on the age hardening behaviour of aluminium alloy AA6060

Quench sensitivity in Al–Mg–Si alloys has been largely attributed to the solute loss at the heterogeneous nucleation sites, primarily dispersoids, during slow cooling after extrusion. As such, the number density of dispersoids, the solute type and concentration are considered to be the key variables for the quench sensitivity. In this study, quench sensitivity and the influence of natural ageing in a lean Al–Mg–Si alloy, AA6060, which contains few dispersoids, have been investigated by hardness measurement, thermal analysis, transmission electron microscopy (TEM) and positron annihilation lifetime spectroscopy (PALS). It is shown that the quench sensitivity in this alloy is associated with the degree of supersaturation of vacancies after cooling. Due to vacancy annihilation and clustering during natural ageing, the quench sensitivity is more pronounced after a short natural ageing time (30 min) compared to a longer natural ageing time (24 h). Therefore, prolonged natural ageing not only leads to an increase in hardness, but can also have a positive effect on the quench sensitivity of lean Al–Mg–Si alloys. - Highlights: • Significant quench sensitivity observed in AA6060 alloy after 30 min natural ageing • Prolonged natural ageing increased hardness and reduced QS. • Low dispersoid density leads to insignificant QS from non-hardening precipitates. • Vacancy supersaturation identified as a contributor to QS.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Synthesis and characterization of aluminophosphate glasses with unique blue emission

Highlights: • Unique blue emission from aluminophosphate glass due to the phosphorus defect. • Tune the blue emission intensity by addition of SiO{sub 2}, ZnF{sub 2}, or Li{sub 2}O to the base glass. • Study the structural defects in the glass by PALS. • Energy transfer from phosphorus defect to Mn{sup 2+} in Mn-doped aluminophosphate glass. - Abstract: The aluminophosphate glasses were prepared by the melting-quenching technique and their optical and structural properties were investigated. The 56P{sub 2}O{sub 5}-20Al{sub 2}O{sub 3} glass exhibits unique blue emission at 406 nm due to the phosphorus defect in the glass matrix. Addition of SiO{sub 2}, ZnF{sub 2}, or Li{sub 2}O to 56P{sub 2}O{sub 5}-20Al{sub 2}O{sub 3} glass matrix has different influence on formation of phosphorus defect resulting in different intensities of blue emission at 406 nm, though SiO{sub 2}, ZnF{sub 2} or Li{sub 2}O mostly enters the glass network as modifier. Structural analysis of P{sub 2}O{sub 5}-Al{sub 2}O{sub 3} based aluminophosphate glasses by positron annihilation lifetime spectroscopy indicates that values of positron lifetimes and the corresponding intensities may be connected with the sizes and number of structural defects. Under excitation of 251 nm, a broad blue emission band and a red emission band were observed in the Mn-doped 56P{sub 2}O{sub 5}-20Al{sub 2}O{sub 3}-15SiO{sub 2}-10ZnF{sub 2} glass, indicating the operation of energy transfer from the phosphorus defect to octahedrally coordinated Mn in the glass host.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Structural, optical and photocatalytic properties of zinc oxides obtained from spent alkaline batteries

Highlights: • Zinc oxides were synthetized using spent alkaline batteries as raw materials. • Both prepared samples present the wurzite structure and exhibits good optical properties. • The decrease in lattice parameters and the narrow band gap are associated with the formation of oxygen vacancies. • Recovered zinc oxides were active for photodegradation of methylene blue by UV irradiation. • The photocatalytic was correlates to the bulk/surface defects ratio. - Abstract: The structural, optical and photocatalytic properties of two zinc oxides prepared from spent alkaline batteries were analysed. After leaching the anode of alkaline batteries, zinc was precipitated from the leachate liquor by introducing oxalic acid (O-ZnO) or sodium carbonate (C-ZnO). The structure of ZnO samples were analysed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), S{sub BET}, DRS-UV-vis spectroscopy and positron annihilation lifetime spectroscopy (PALS). Both oxides present the ZnO wurzite structure and similar morphology. C-ZnO presents a cell lower lattice parameters and bang gap energy (2.99 eV) than O-ZnO (3.05 eV), possibly due to higher concentration of oxygen vacancies. The photocatalytic activity in the degradation of methylene blue (MB) of O-ZnO (achieving 70% MB degradation at 90 min) was superior to C-ZnO, due to its higher surface area and degree of crystallinity and lower bulk/surface defects ratio.

36 MATERIALS SCIENCE↗
DOE OSTI2017

New Class of Type III Porous Liquids: A Promising Platform for Rational Adjustment of Gas Sorption Behavior

Porous materials have already manifested their unique properties in a number of fields. Generally, all porous materials are in a solid state other than liquid, in which molecules are closely packed without porosity. “Porous” and “liquid” seem like antonyms. In this paper, we report a new class of Type 3 porous liquids based on rational coupling of microporous framework nanoparticles as porous hosts with a bulky ionic liquid as the fluid media. Positron annihilation lifetime spectroscopy (PALS) and CO 2 adsorption measurements confirm the successful engineering of permanent porosity into these liquids. Compared to common porous solid materials, as-synthesized porous liquids exhibited pronounced hysteresis loops in the CO 2 sorption isotherms even at ambient conditions (298 K, 1 bar). Finally, the unique features of these novel porous liquids could bring new opportunities in many fields including gas separation and storage, air separation and regeneration, gas transport, and permanent gas storage at ambient conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2023

High-Throughput Characterization and Optimization of Polyamide Hydrolase Activity Using Open Port Sampling Interface Mass Spectrometry

Enzymatic biodegradation of polymers, such as polyamides (PA), has the potential to cost-effectively reduce plastic waste, but enhancements in degradation efficiency are needed. Engineering enzymes through directed evolution is one pathway toward identification of critical domains needed for improving activity. However, screening such enzymatic libraries (100s-to-1000s of samples) is time-consuming. Here we demonstrate the use of robotic autosampler (PAL) and immediate drop on demand technology (I.DOT) liquid handling systems coupled with open-port sampling interface-mass spectrometry (OPSI-MS) to screen for PA6 and PA66 hydrolysis by 6-aminohexanoate-oligomer endo-hydrolase (nylon hydrolase, NylC) in a high-throughput (8–20 s/sample) manner. The OPSI-MS technique required minimal sample preparation and was amenable to 96-well plate formats for automated processing. Enzymatic hydrolysis of PA characteristically produced soluble linear oligomer products that could be identified by OPSI-MS. Incubation temperatures and times were optimized for PA6 (65 °C, 24 h) and PA66 (75 °C, 24 h) over 108 experiments. In addition, the I.DOT/OPSI-MS quantified production of PA6 linear dimer (8.3 ± 1.6 μg/mL) and PA66 linear monomer (13.5 ± 1.5 μg/mL) by NylC with a lower limit of detection of 0.029 and 0.032 μg/mL, respectively. For PA6 and PA66, linear oligomer production corresponded to 0.096 ± 0.018% and 0.204 ± 0.028% conversion of dry pellet mass, respectively. The developed methodology is expected to be utilized to assess enzymatic hydrolysis of engineered enzyme libraries, comprising hundreds to thousands of individual samples.

47 OTHER INSTRUMENTATION↗
DOE OSTI2015

An overview of selected current approaches to the characterization of aqueous inorganic clusters

This Perspective article highlights some of the traditional and non-traditional analytical tools that are currently used to characterize aqueous inorganic nanoscale clusters and polyoxometalate ions. The techniques discussed in this article include nuclear magnetic resonance spectroscopy (NMR), small angle X-ray scattering (SAXS), dynamic and phase analysis light scattering (DLS and PALS), Raman spectroscopy, and quantum mechanical computations (QMC). For each method we briefly describe how it functions and illustrate how these techniques are used to study cluster species in the solid state and in solution through several representative case studies. In addition to highlighting the utility of these techniques, we also discuss limitations of each approach and measures that can be applied to circumvent such limits as it pertains to aqueous inorganic cluster characterization.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Secondary particle production from laser accelerated beams

3-MeV protons and fusion neutrons are generated by focused radiation of the 3-TW Prague Asterix Laser System (PALS). 30-mA current of 3-MeV protons is detected behind the target in the forward direction when a hydrogenated silicon foil is used. The co-occurrence of bursts in the emission of ions and fusion neutrons from CD{sub 2} plasma is observed. The energy of produced deuteron bursts is high enough to drive deuterium fusion in CD{sub 2} catcher targets.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Thomson parabola spectrometry for gold laser-generated plasmas

The plasma generated from thin gold films irradiated in high vacuum at high intensity ({approx}10{sup 15} W/cm{sup 2}) laser shot is characterized in terms of ion generation through time-of-flight techniques and Thomson parabola spectrometry. Gold ions and protons, accelerated in forward direction by the electric field developed in non-equilibrium plasma, have been investigated. Measurements, performed at PALS laboratory, give information about the gold charge states distributions, the ion energy distributions and the proton acceleration driven as a function of film thickness, laser parameters, and angular emission. The ion diagnostics of produced plasma in forward direction permits to understand some mechanisms developed during its expansion kinetics. The role of the focal position of a laser beam with respect to the target surface, plasma properties, and the possibility to accelerate protons up to energies above 3 MeV has been presented and discussed.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2013

High-energy resolution Thomson Parabola spectrometer for laser plasma diagnostics

Thomson Parabola (TP) spectrometers are widely used devices for laser-driven beam diagnostics as they provide a complete set of information on the accelerated particles. A novel TP has been developed at LNS with a design able to detect protons up to 20 MeV. The layout design and some results obtained during the experimental campaign at PALS laboratory will be reported in the following.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Generation of high pressure shocks relevant to the shock-ignition intensity regime

An experiment was performed using the PALS laser to study laser-target coupling and laser-plasma interaction in an intensity regime ≤10{sup 16} W/cm{sup 2}, relevant for the “shock ignition” approach to Inertial Confinement Fusion. A first beam at low intensity was used to create an extended preformed plasma, and a second one to create a strong shock. Pressures up to 90 Megabars were inferred. Our results show the importance of the details of energy transport in the overdense region.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Generation of ultra-high-pressure shocks by collision of a fast plasma projectile driven in the laser-induced cavity pressure acceleration scheme with a solid target

A novel, efficient method of generating ultra-high-pressure shocks is proposed and investigated. In this method, the shock is generated by collision of a fast plasma projectile (a macro-particle) driven by laser-induced cavity pressure acceleration (LICPA) with a solid target placed at the LICPA accelerator channel exit. Using the measurements performed at the kilojoule PALS laser facility and two-dimensional hydrodynamic simulations, it is shown that the shock pressure ∼ Gbar can be produced with this method at the laser driver energy of only a few hundred joules, by an order of magnitude lower than the energy needed for production of such pressure with other laser-based methods known so far.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Oxygen ion implantation induced microstructural changes and electrical conductivity in Bakelite RPC detector material

In order to explore the structural modification induced electrical conductivity, samples of Bakelite Resistive Plate Chamber (RPC) detector materials were exposed to 100 keV Oxygen ion in the fluences of 10{sup 12}, 10{sup 13}, 10{sup 14} and 10{sup 15} ions/cm{sup 2}. Ion implantation induced microstructural changes have been studied using Positron Annihilation Lifetime Spectroscopy (PALS) and X-Ray Diffraction (XRD) techniques. Positron lifetime parameters viz., o-Ps lifetime and its intensity shows the deposition of high energy interior track and chain scission leads to the formation of radicals, secondary ions and electrons at lower ion implantation fluences (10{sup 12} to10{sup 14} ions/cm{sup 2}) followed by cross-linking at 10{sup 15} ions/cm{sup 2} fluence due to the radical reactions. The reduction in electrical conductivity of Bakelite detector material is correlated to the conducting pathways and cross-links in the polymer matrix. The appropriate implantation energy and fluence of Oxygen ion on polymer based Bakelite RPC detector material may reduce the leakage current, improves the efficiency, time resolution and thereby rectify the aging crisis of the RPC detectors.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Investigations on the structure of Pb-Ge-Se glasses

Chalcogenide glasses have attracted much attention because of their potential application in various solid state devices. In the present work, we report here the detailed thermal, structural, microstructural studies on Pb{sub x}Ge{sub 42-x}Se{sub 58} with (0 ≤ x ≤ 20) glasses. The influence of Pb content on the glass transition temperature, specific heat, and non-reversing enthalpy is observed and discussed qualitatively The Raman spectroscopic studies on the all the glass compositions are carried out and deconvoluted into different structural units. The positron annihilation life-time spectroscopy (PALS) studies helped to understand the nature of defect states present in the glassy system and its variation with Pb content. The concentration of charged defect centers is found to increase, whereas the open volume defect concentration decreases with Pb content in these glasses.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗