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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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78 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Element-specific first order reversal curves measured by magnetic transmission x-ray microscopy

The first-order reversal curve (FORC) method is a macroscopic measurement technique that can be used to extract quantitative and microscopic properties of hysteretic systems. Using magnetic transmission x-ray microscopy (MTXM), local element-specific FORC measurements are performed on a 20 nm thick film of CoTb. The FORCs measured with microscopy reveal a step-by-step domain evolution under the magnetic field cycling protocol and provide a direct visualization of the mechanistic interpretation of FORC diagrams. They are compared with magnetometry FORCs and show good quantitative agreement. Furthermore, the high spatial resolution and element-specific sensitivity of MTXM provide new capabilities to measure FORCs in small regions or specific phases within multicomponent systems, including buried layers in heterostructures. The ability to perform FORCs on very small features is demonstrated with the MTXM-FORC measurement of a rectangular microstructure with vortex-like Landau structures. This work demonstrates the confluence of two uniquely powerful techniques to achieve quantitative insight into nanoscale magnetic behavior.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Study of an unrefined humate solution as a possible remediation method for groundwater contamination - 15698

Savannah River Site (SRS) was one of the major nuclear processing facilities in the U.S. where plutonium was produced during the Cold War. Approximately 1.8 billion gallons of low level acidic waste solution containing radionuclides and dissolved metals were discharged to a series of unlined seepage basins at the F/H Area. Uranium is a key contaminant of concern in the basin's groundwater. It is migrating into the groundwater creating an acidic plume with a pH between 3-5.5. Groundwater Actions: The pump-and-treat water treatment unit was designed and built in 1997 to remove metals and radionuclides. In 2004 a hybrid funnel-and-gate system was constructed to create a treatment zone in which the acidic nature of the contaminated sediments could be reversed. Huma-K is an organic fertilizer that comes from the alkaline extraction of leonardite (a low-rank coal). Huma-K has a high content of humic substances which consist of complex organic compounds formed by the decomposition of plant and animal tissue. The objective of this study is to determine if a low cost unrefined humate solution (Huma-K) can be used to facilitate uranium adsorption to control its mobility in acidic groundwater. This study can assist in evaluating whether Huma-K can be used as an in situ amendment for the remediation of groundwater contaminated with uranium. Sediments from FAW-1 70-90 ft were used in this experiment. Sediments were disaggregated and sieved to a particle size of . 2 mm. Concentrations in the range 10-500 ppm were tested. Once all the components were added, pH was adjusted to 4. Samples were vortex mixed and placed on a shaker table at 100 RPM for a period of 24 hours in order to reach the adsorption equilibrium. Once the adsorption equilibrate was reached, samples were centrifuged at 2700 RPM to separate the liquid and the solid phase. The liquid fraction was analyzed using a Thermo Scientific Genesys 10S UV-Vis spectrophotometer. The same experimental design was used as explained above. A known concentration of Huma-K was used to study the pH effect on the sorption process. pH values were measured at the beginning and at the end of the experiment. Spectra of Huma-K show a featureless character. Absorbance of light increases as the wavelength is decreased. Measurements were done at 254 nm due to the presence of aromatic rings. Apparently there are two sorption processes. The first one follows the same trend as the Langmuir isotherm up to 250 ppm. The second sorption process occurs after all the binding sites in the sediments have been occupied. Precipitation decreases as the pH is increased. Based on the sorption isotherm, humic substances apparently bind first to the binding sites of the sediments particles. Once all the binding sites have been occupied, other sorption processes may start to dominate. Sorption is affected by pH. Higher sorption is seen at low pH values. Increased precipitation at low pH values is probably due to the neutralization of surface charges of humic molecules making them agglomerate.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

SCPAssistant v1.20

Critical need to rapidly and quantitatively measure the chemistry of single cells in their natural state, without extensive sample preparation procedures. Developed at ORNL an innovative single cell droplet ejection-liquid vortex capture mass spectrometry (SCDE-LVC-MS) platform for rapid, in situ molecular characterization of single cells in suspension. This platform provides rapid, quantitative, targeted and/or untargeted mass spectrometric analysis of single cells without extensive sample preparation procedures. Enable real-time untargeted mass spectrometry analysis of chemical constituents of single cells in their native environment. Send a TTL signal via a connected AD/DA board to start mass spectrometry (MS) data acquisition - analyze MS data - classification of analyzed samples (e.g. separate single cell types based on their chemistry) - quantitation of analyzed samples (e.g. quantify lipids in single cells). List of features: external instrument control; screen capture; reporting; real-time MS data (single cell) analysis; classification; quantitation. Specific application: real-time mass spectrometry analysis of chemical constituents of single cells in their native environment. The software starts MS acquisition; then monitors a folder where the Cytena Single Cell Printer saves images of ejected single cells; real-time extracts MS spectra from MS files for a) either classification of single cells, or b) quantitation of (a) chemical constituent(s) of single cells.

Kertesz, Vilmos↗
DOE OSTI2016

Experimental Activities with the IELLLO Lithium-Lead Facility

Fusion power offers the prospect of an almost inexhaustible source of energy for future generations. Although this may be true, it also presents so far serious scientific and engineering challenges. Breeding Blanket is one of key components of future fusion reactors, since it directly involves tritium breeding and energy extraction, both of them critical to development of fusion power. To deal with the development of Breeding Blankets, ENEA (Italian National Agency for New Technologies, Energy and Sustainable Economic Development) designed and built a lead lithium loop (IELLLO: Integrated European Lead Lithium Loop): the experiment aims to support R and D activities for the conceptual and preliminary design of the European test blanket systems. IELLLO was completed, installed and operated at ENEA Brasimone Research Centre. The purpose of this work is to describe the experimental activities that have been carried out concerning the qualification of the facility, and relative instrumentations, for lead lithium applications. A series of thermo-hydraulic investigations on IELLLO facility has been elaborated: lead lithium pressure transducers, heat exchanger, permanent magnet pumping system, mass flow meters and air cooler have been tested. The absolute pressure meter in contact with Pb-16Li was qualified in pressure range up to 10 bar and temperature up to 400 deg. C. The installation of new kinds of Pb-16Li differential pressure transducers will allow to check the pump characteristic curve and accurately calculate valves pressure drops. These factors could give a better information for the thermo-hydraulic qualification of the facility. Vortex Mass Flow Meter has shown good results in terms of accuracy. The performance has been validated by thermal balance with a dedicated heating system. Nevertheless, the installations of different types of mass flow meters will enable to test IELLLO at ITER relevant conditions, and at lower mass flow rates than those tested up to now. The new pumping system with a PM Pump, was qualified for the first time in Pb-16Li, and the procedure for the operation and maintenance of the pump was developed. The pump is able to supply a mass flow rate in the range from 1.2 to 2.4 kg/s with a temperature of Pb-16Li up to 550 deg. C in the test section. Significant results have been obtained also for the heat exchanger, which has shown high efficiencies, even more than expected. Likewise, the Air Cooler has been verified to be able to cool Pb-16Li in a relatively short time, even at the worst temperature and mass flow conditions. (authors)

42 ENGINEERING↗
DOE OSTI2022

Hydrokinetic energy conversion using flow induced oscillations of single-cylinder with large passive turbulence control

Various types of flow-induced oscillations (FIOs) have been implemented in development of marine hydrokinetic (MHK) energy converters. With passive turbulence control (PTC), energy harvesting starts at a flow speed of about 0.5 m/s. However, there is worldwide MHK energy available in even slower currents. In the present study, the effect of damping on FIO and power extraction is investigated for a converter with large turbulence stimulation (PTC) consisting of straight strips with a height of 15% of the cylinder diameter and placed symmetrically on the cylinder surface. The oscillating amplitude decreases, as the damping ratio increases, with unchanged sinusoidal pattern of the displacement time-history. The frequency ratio is also affected by damping especially in the VIV initial branch and transition region between VIV and galloping. An important flow characteristic of the large-PTC cylinder is that a recirculation region is formed behind the PTC, causing appreciable disturbance to the flow past the cylinder. Power can be harvested in the whole FIO range and the harnessed power maximum appears at the largest inflow velocity tested. However, the optimum of harnessing efficiency is located at the beginning of the VIV upper branch. The gap between VIV and galloping is bridged when large PTC is used, eliminating the drop in power and efficiency even at higher damping, which would be a weakness of regular-PTC cylinder for energy harvesting. Finally, the mechanism behind the variation of harnessing efficiency with inflow velocity and damping ratio is revealed, and the optimality criterion for the converter design is discussed.

16 TIDAL AND WAVE POWER↗
DOE OSTI2014

Modelling and analysis of turbulent datasets using Auto Regressive Moving Average processes

We introduce a novel way to extract information from turbulent datasets by applying an Auto Regressive Moving Average (ARMA) statistical analysis. Such analysis goes well beyond the analysis of the mean flow and of the fluctuations and links the behavior of the recorded time series to a discrete version of a stochastic differential equation which is able to describe the correlation structure in the dataset. We introduce a new index Υ that measures the difference between the resulting analysis and the Obukhov model of turbulence, the simplest stochastic model reproducing both Richardson law and the Kolmogorov spectrum. We test the method on datasets measured in a von Kármán swirling flow experiment. We found that the ARMA analysis is well correlated with spatial structures of the flow, and can discriminate between two different flows with comparable mean velocities, obtained by changing the forcing. Moreover, we show that the Υ is highest in regions where shear layer vortices are present, thereby establishing a link between deviations from the Kolmogorov model and coherent structures. These deviations are consistent with the ones observed by computing the Hurst exponents for the same time series. We show that some salient features of the analysis are preserved when considering global instead of local observables. Finally, we analyze flow configurations with multistability features where the ARMA technique is efficient in discriminating different stability branches of the system.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗