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Results for “quantitative analysis”

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 1,765 records · Page 98
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

High temperature polymer degradation: Rapid IR flow-through method for volatile quantification

Accelerated aging of polymers at elevated temperatures often involves the generation of volatiles. These can be formed as the products of oxidative degradation reactions or intrinsic pyrolytic decomposition as part of polymer scission reactions. A simple analytical method for the quantification of water, CO 2 , and CO as fundamental signatures of degradation kinetics is required. Here, we describe an analytical framework and develops a rapid mid-IR based gas analysis methodology to quantify volatiles that are contained in small ampoules after aging exposures. The approach requires identification of unique spectral signatures, systematic calibration with known concentrations of volatiles, and a rapid acquisition FTIR spectrometer for time resolved successive spectra. Furthermore, the volatiles are flushed out from the ampoule with dry N2 carrier gas and are then quantified through spectral and time integration. This method is sufficiently sensitive to determine absolute yields of ~50 μg water or CO 2 , which relates to probing mass losses of less than 0.01% for a 1 g sample, i.e. the early stages in the degradation process. Such quantitative gas analysis is not easily achieved with other approaches. Our approach opens up the possibility of quantitative monitoring of volatile evolution as an avenue to explore polymer degradation kinetics and its dependence on time and temperature.

36 MATERIALS SCIENCE↗
NASA NTRS2019

Quantitative Technology Assessment in Space Mission Analysis

New technologies will need to be developed to create feasible concepts for NASA's ambitious missions of the future, but quantitative assessments of the impacts that technologies have on systems or architectures are sporadic and often inadequate. The Space Mission Analysis Branch at NASA's Langley Research Center is developing a quantitative technology assessment framework to address this issue with a vision of being able to understand the mission and system architecture impacts of technology development activities. A phased approach is being pursued to answer technology needs assessment and technology forecasting questions. First, the integration of subject matter experts, data collection, and data analysis techniques ensures that the framework is accessible and analyzable. Second, systems analysis determines the impact of key technologies from the first phase on systems, architectures, and campaigns. The goal of a quantitative technology assessment framework is to accelerate technology assessments, to improve the accuracy of those assessments, and to provide deeper insights into the impact of new technologies. Keywords: technology assessment, data analysis, systems analysis.

Arney, Dale C.↗
NASA NTRS1983

Characterization of ceramic powders by an X-ray measuring method

X-ray line broadening analysis gives quantitative data on structural changes of ceramic powders after different processing steps. Various Al2O3 powders were investigated and the following points are discussed on the basis of these results: X-ray line broadening analysis, structural changes during grinding, structural changes during annealing, influence of structural properties on sintering behavior and application of line broadening analysis to quality control of powders.

Ziegler, B.↗
DOE OSTI2020

Discrete spherical harmonic functions for texture representation and analysis

A basis of discrete harmonic functions for efficient representation and analysis of crystallographic texture is presented. Discrete harmonics are a numerical representation of the harmonics on the sphere. A finite element formulation is utilized to calculate these orthonormal basis functions, which provides several advantageous features for quantitative texture analysis. These include high-precision numerical integration, a simple implementation of the non-negativity constraint and computational efficiency. Simple examples of pole figure and texture interpolation and of Fourier filtering using these basis sets are presented.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Mass Spectrometry-Based High-Throughput Quantification of Bioproducts in Liquid Culture

To meet the ever-increasing need for high-throughput screening in metabolic engineering, information-rich, fast screening methods are needed. Mass spectrometry (MS) provides an efficient and general approach for metabolite screening and offers the capability of characterizing a broad range of analytes in a label-free manner, but often requires a range of sample clean-up and extraction steps. Liquid extraction surface analysis (LESA) coupled MS is an image-guided MS surface analysis approach that directly samples and introduces metabolites from a surface to MS. Here, we combined the advantages of LESA–MS and an acoustic liquid handler with stable isotope-labeled internal standards. This approach provides absolute quantitation of target chemicals from liquid culture-dried droplets and enables high-throughput quantitative screening for microbial metabolites. In this paper, LESA–MS was successfully applied to quantify several different metabolites (itaconic acid, triacetic acid lactone, and palmitic acid) from different yeast strains in different mediums, demonstrating its versatility, accuracy, and efficiency across a range of microbial engineering applications.

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

Design and analysis of confirmation experiments

The statistical literature and practitioners have long advocated the use of confirmation experiments as the final stage of a sequence of designed experiments to verify that the optimal operating conditions identified as part of a response surface methodology strategy are attainable and able to achieve the value of the response desired. Yet, until recently there has been a gap between this recommendation and details about how to perform an analysis to quantitatively assess whether the confirmation runs are adequate. Likewise, there has been little in the way of specific recommendations for the number and nature of the confirmation runs that should be performed. In this article, we propose analysis methods to assess agreement between the mean response from previous experiments and the confirmation experiment, and suggest a strategy for the design of confirmation experiments that more fully explores the region around the optimum.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Uranium Oxide Synthetic Pathway Discernment through Unsupervised Morphological Analysis

We present a novel unsupervised machine learning method for quantitative representation of scanning electron micrographs and its applications and performance for nuclear forensic analysis of uranium ore concentrates. The method uses a vector quantizing variational autoencoder followed by a histogram operation to encode a micrograph into a single dimensional representation, called the latent vector. The method requires no extant labeling of the data and can be applied over large datasets of micrographs with minimal human interaction. The representations generated are broadly descriptive of each micrograph and the microstructure of the material imaged. In the case of uranium ore concentrate analysis, the representations were amenable to processing reagent and ore concentrate species classification with accuracy of 81:8%, which is competitive with state-of-the-art supervised networks. The representations were also used to classify previously unseen processing routes, were able to classify imaging parameters such as magnification (to 76:0% accuracy), were able to classify fine grained process parameters such as calcining temperature (to 74:4% accuracy), and their informatic properties indicate that they are generally descriptive of the image represented. This method can be applied across microstructure analysis fields to perform quantitative analysis without the need for labor intensive and possibly biased human analysis.

Scanning Electron Microscopy, Vector Quantizing Va↗
NASA NTRS1988

Analysis of a used pair of arcjet electrodes

The anode and cathode of a 30-kW class arcjet engine have been sectioned and analyzed. This arcjet was operated for a total time of 573 hours at power levels between 25 and 30 kW with ammonia at flow rates of 0.25 and 0.27 gm/s. The accumulated run time was sufficient to clearly establish erosion patterns and their causes. The type of electron emission from various parts of the cathode surface was made clear by Scanning Electron Microscope analysis. A Scanning Electron Microscope was used to study recrystallization on the hot anode surface. These electrodes were made of 2 percent thoriated tungsten and the surface thorium content and gradient perpendicular to the surfaces was determined by quantitative microprobe analysis. The results of this material analysis on the electrodes and recommendations for improving electrode operational life time are presented.

Pivirotto, Thomas J.↗
NASA NTRS1988

Electrode erosion in steady-state electric propulsion engines

The anode and cathode of a 30 kW class arcjet engine were sectioned and analyzed. This arcjet was operated for a total time of 573 hr at power levels between 25 and 30 kW with ammonia at flow rates of 0.25 and 0.27 gm/s. The accumulated run time was sufficient to clearly establish erosion patterns and their causes. The type of electron emission from various parts of the cathode surface was made clear by scanning electron microscope analysis. A scanning electron microscope was used to study recrystallization on the hot anode surface. These electrodes were made of 2 percent thoriated tungsten and the surface thorium content and gradient perpendicular to the surfaces was determined by quantitative microprobe analysis. The results of this material analysis on the electrodes and recommendations for improving electrode operational life time are presented.

Pivirotto, Thomas J.↗
DOE OSTI2014

Landscape Characterization and Representativeness Analysis for Understanding Sampling Network Coverage

Sampling networks rarely conform to spatial and temporal ideals, often comprised of network sampling points which are unevenly distributed and located in less than ideal locations due to access constraints, budget limitations, or political conflict. Quantifying the global, regional, and temporal representativeness of these networks by quantifying the coverage of network infrastructure highlights the capabilities and limitations of the data collected, facilitates upscaling and downscaling for modeling purposes, and improves the planning efforts for future infrastructure investment under current conditions and future modeled scenarios. The work presented here utilizes multivariate spatiotemporal clustering analysis and representativeness analysis for quantitative landscape characterization and assessment of the Fluxnet, RAINFOR, and ForestGEO networks. Results include ecoregions that highlight patterns of bioclimatic, topographic, and edaphic variables and quantitative representativeness maps of individual and combined networks.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

Perturbations in the Urinary Exosome in Transplant Rejection

Background: Urine exosomes, vesicles exocytosed into urine by all renal epithelial cell types, occur under normal physiologic and disease states. Exosome contents may mirror disease-specific proteome perturbations in kidney injury. Analysis methodologies for the exosomal fraction of the urinary proteome were developed and for comparing the urinary exosomal fraction versus unfractionated proteome for biomarker discovery. Methods: Urine exosomes were isolated by centrifugal filtration from mid-stream, second morning void, urine samples collected from kidney transplant recipients with and without biopsy matched acute rejection. The proteomes of unfractionated whole urine (Uw) and urine exosomes (Uexo) underwent mass spectrometry-based quantitative proteomics analysis. The proteome data were analyzed for significant differential protein abundances in acute rejection (AR). Results: Identifications of 1018 and 349 proteins, Uw and Uexo fractions, respectively, demonstrated a 279 protein overlap between the two urinary compartments with 25%(70) of overlapping proteins unique to Uexoand represented membrane bound proteins (p=9.31e-7). Of 349 urine exosomal proteins identified in transplant patients 220 were not previously identified in the normal urine exosomal fraction. Uexo proteins (11), functioning in the inflammatory / stress response, were more abundant in patients with biopsy-confirmed acute rejection, 3 of which were exclusive to Uexo. Uexo AR-specific biomarkers (8) were also detected in Uw, but since they were observed at significantly lower abundances in Uw, they were not significant for AR in Uw. Conclusions: A rapid urinary exosome isolation method and quantitative measurement of enriched Uexo proteins was applied. Urine proteins specific to the exosomal fraction were detected either in unfractionated urine (at low abundances) or by Uexo fraction analysis. Perturbed proteins in the exosomal compartment of urine collected from kidney transplant patients were specific to inflammatory responses, and were not observed in the Uexo fraction from normal healthy subjects. Uexo specific protein alterations in renal disease provide potential mechanistic insights and offer a unique panel of sensitive biomarkers for monitoring for acute transplant rejection.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2015

Thermoreversible and Injectable ABC Polypeptoid Hydrogels: Controlling the Hydrogel Properties through Molecular Design

Here, a series of ABC triblock copolypeptoids [i.e., poly( N -allyl glycine)- b -poly( N -methyl glycine)-b-poly( N -decyl glycine) (AMD)] with well-defined structure and varying composition have been synthesized by sequential primary amine-initiated ring-opening polymerization of the corresponding N-substituted N -carboxyanhydride monomers (Al-NCA, Me-NCA, and De-NCA). The ABC block copolypeptoids undergo sol-to-gel transitions with increasing temperature in water and biological media at low concentrations (2.5–10 wt %). The sol–gel transition is rapid and fully reversible with a narrow transition window, evidenced by the rheological measurements. The gelation temperature ( T gel ) and mechanical stiffness of the hydrogels are highly tunable: T gel in the 26.2–60.0 °C range, the storage modulus (G') and Young’s modulus ( E ) in the 0.2–780 Pa and 0.5–2346 Pa range, respectively, at the physiological temperature (37 °C) can be readily accessed by controlling the block copolypeptoid composition and the polymer solution concentration. The hydrogel is injectable through a 24 gauge syringe needle and maintains their shape upon in contact with surfaces or water baths that are kept above the sol–gel transition temperature. The hydrogels exhibit minimal cytotoxicity toward human adipose derived stem cells (hASCs), evidenced from both alamarBlue and PicoGreen assays. Furthermore, quantitative PCR analysis revealed significant up-regulation of the Col2a1 gene and down-regulation of ANGPT1 gene, suggesting that the hydrogel exhibit biological activity in inducing chondrogenesis of hASCs. It was also demonstrated that the hydrogel can be used to quantitatively encapsulate water-soluble enzymes (e.g., horseradish peroxidase) by manipulating the sol–gel transition. The enzymatic activity of HRP remain unperturbed after encapsulation at 37 °C for up to 7 d, suggesting that the hydrogel does not adversely affect the enzyme structure and thereby the enzymatic activity. These results suggest that the polypeptoid hydrogel a promising synthetic platform for tissue engineering or protein storage applications.

36 MATERIALS SCIENCE↗
NASA NTRS2002

Mars Global Surveyor Data Analysis Program. Origins of Small Volcanic Cones: Eruption Mechanisms and Implications for Water on Mars

The goal of the proposed work was to determine the origins of small volcanic cones observed in Mars Global Surveyor (MGS) data, and their implications for regolith ice stores and magma volatile contents. For this 1-year study, our approach involved a combination of: Quantitative morphologic analysis and interpretation of Mars Orbiter Camera (MOC) and Mars Orbiter Laser Altimeter (MOLA) data; Numerical modeling of eruption processes responsible for producing the observed features; Fieldwork on terrestrial analogs in Iceland. Following this approach, this study succeeded in furthering our understanding of (i) the spatial and temporal distribution of near-surface water ice, as defined by the distribution and sizes of rootless volcanic cones ("pseudocraters"), and (ii) the properties, eruption conditions, and volatile contents of magmas producing primary vent cones.

Fagents, Sarah A.↗
DOE OSTI2026

Classifying biophysical subpopulations of insulin secretory granules using quantitative whole-cell structure analysis

Pancreatic beta cells contain insulin secretory granules (ISGs), organelles where proinsulin is converted into insulin. As ISGs mature, they undergo extensive biophysical remodeling, producing a spectrum of subpopulations with heterogeneous molecular and spatial characteristics. However, systematic methods to define ISG subpopulations remain underdeveloped. To address this gap in knowledge, we employed soft X-ray tomography (SXT), which can quantitatively measure the biochemical density of ISGs within whole beta cells. Using unsupervised clustering, we classified subpopulations based on molecular density, size, and spatial positioning. Across different insulin secretory stimuli, we observed shifts toward mature and releasable subtypes, demonstrating that exogenous signals can dynamically remodel ISG subpopulation distributions. We extended this methodology to primary beta cells characterized using volume electron microscopy (vEM). Integrating subpopulations from SXT and vEM uncovered insights inaccessible by a single method in isolation. This strategy establishes a framework for defining therapeutic approaches aimed at enriching physiologically beneficial ISG subpopulations.

dense-core granules↗
DOE OSTI2022

Rapid Targeted Quantitation of Protein Overexpression with Direct Infusion Shotgun Proteome Analysis (DISPA-PRM)

While much effort has been placed on comprehensive quantitative proteome analysis, certain applications demand measurement of only a few target proteins from complex systems. Traditional approaches to targeted proteomics rely on nano-liquid chromatography (nLC) and targeted mass spectrometry (MS) methods, e.g., parallel reaction monitoring (PRM). However, the time requirement for nLC can limit throughput of targeted proteomics. To achieve rapid and high-throughput targeted methods, here we show that nLC separations can be eliminated and replaced with direct infusion shotgun proteome analysis (DISPA) using high-field asymmetric waveform ion mobility spectrometry (FAIMS) with PRM. We demonstrate application of DISPA-PRM for rapid targeted quantification of bacterial enzymes utilized in the production of biofuels by monitoring temporal expression in 72 metabolically engineered bacterial cultures in under 2.5 hours, with a measured dynamic range >1200-fold. Here, we conclude that DISPA-PRM presents a valuable innovative tool with results comparable to nLC-MS/MS, enabling fast and rapid detection of targeted proteins in complex mixtures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Femtosecond filament-laser ablation molecular isotopic spectrometry

A new remote sensing technology for real-time isotopic analysis is introduced: Femtosecond Filament-Induced Laser Ablation Molecular Isotopic Spectrometry (F 2 -LAMIS). The technique combines femtosecond (fs) laser filamentation and ablation-based molecular isotopic spectroscopy, thereby enabling isotopic analysis of samples at a distance, in ambient air and at ambient pressure conditions. Isotopic analysis of zirconium (Zr) samples by F 2 -LAMIS is demonstrated, and the molecular and atomic emission intensity, and properties of the filament-induced plasma generated at different filament propagation distances were investigated. Spectral fitting of F 2 -LAMIS spectra enabled semi-quantitative isotopic analysis without the use of calibration standards, which was independent of the filament propagation distance for the studied range. As a result, this technology provides new capabilities for direct isotopic ratio measurements at remote distances.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

A data-driven analysis of the heavy quark transport coefficient

Using a Bayesian model-to-data analysis, we estimate the temperature dependence of the heavy quark diffusion coefficients by calibrating to the experimental data of D-meson R AA and v 2 in AuAu collisions ($\sqrt{s}$NN = 200 GeV) and PbPb collisions ($\sqrt{s}$NN = 2.76 TeV) [1]. The spatial diffusion coefficient D s 2πT is found to be mostly constraint around (1.3 1.5)T c and is compatible with lattice QCD calculations. Here we demonstrate the capability of our improved Langevin model to simultaneously describe the R AA and v 2 at both RHIC and the LHC energies, as well as the feasibility to apply a Bayesian analysis to quantitatively study the heavy flavor transport in heavy-ion collisions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗