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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2013

Stability of carbon fiber surface chemistry under temperature and its influence on interfacial adhesion with polymer matrices

The thermal stability of the surface chemistry of a surface treated carbon fiber was investigated by X-ray Photoelectron Spectroscopy. Within a range of temperatures from room temperature to 400 C, the only surface functionalities that decomposed were carboxylic acids and dangling nitrogen containing functionalities like amines, amides or nitriles. Significant amounts of water were desorbed as well. This study enabled the testing of the coherence our the fitting of the C(1s), O(1s) and N(1s) peaks. Particularly, when considering the fitting of in the O(1s) peak, carboxylic acids were shown to be included in a single component peak centered at a binding energy of 532.1 eV. The reaction of the carbon fiber surface and an acrylate resin at high temperature, because of the decomposition of carboxylic acids, was highlighted by Differential Scanning Calorimetry. The thermal history of the composite material during its manufacture appeared to be a major influence on the nature of the interactions generated at the fiber-matrix interface and the resulting mechanical properties.

Vautard, Frederic↗
DOE OSTI2018

Development of a fast and efficient analytical technique for the isotopic analysis of fission and actinide elements in environmental matrices

An automated separation–direct analysis scheme has been developed to determine both the concentration and isotopic composition of a suite of elements down to the low picogram level in a complex silicon-based matrix. With the ultimate goal of performing rapid analysis of materials with non-natural isotopic compositions, RAPID (Rapid Analysis of Post-Irradiation Debris) consists of a high-pressure ion chromatography system directly coupled to an inductively coupled plasma mass spectrometer. The RAPID method achieves matrix exclusion and direct online analysis of the elementally separated components, yielding precise isotopic compositions for up to 40 elements in less than one hour per sample. When combined with isotope dilution, this approach shows the potential to yield elemental concentrations with low uncertainties, providing a rapid analytical method that encompasses group I and II metals, transition metals, refractory metals, platinum group metals, lanthanides, and actinides. Furthermore, the method development, robustness, sensitivity, uncertainties, and potential applications in nuclear and environmental measurements will be discussed in this paper.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

Mineral changes in cement-sandstone matrices induced by biocementation

Prevention of wellbore CO 2 leakage is a critical component of any successful carbon capture, utilization, and storage program. Sporosarcina pasteurii is a bacterium that has demonstrated the potential ability to seal a compromised wellbore through the enzymatic precipitation of CaCO 3 . In this paper, we investigate the growth of S. pasteurii in a synthetic brine that mimics the Illinois Basin and on Mt. Simon sandstone encased in Class H Portland cement under high pressure and supercritical CO 2 (P CO2 ) conditions. The bacterium grew optimum at 30 °C compared to 40 °C under ambient and high pressure (10 MPa) conditions; and growth was comparable in experiments at high P CO2 . Sporosarcina pasteurii actively induced the biomineralization of CaCO 3 polymorphs and MgCa(CO 3 ) 2 in both ambient and high pressure conditions as observed in electron microscopy. In contrast, abiotic (non-biological) samples exposed to CO 2 resulted in the formation of surficial vaterite and calcite. Finally, the ability of S. pasteurii to grow under subsurface conditions may be a promising mechanism to enhance wellbore integrity.

58 GEOSCIENCES↗