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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Fe{sub 3}O{sub 4}/Zeolite nanocomposites synthesized by microwave assisted coprecipitation and its performance in reducing viscosity of heavy oil

Fe{sub 3}O{sub 4}/Zeolite nanocomposites have been synthesized via microwave assisted coprecipitation method and show to be efficient in reducing viscosity of heavy oil compared to other Fe{sub 3}O{sub 4}/Zeolite nanocomposites prepared by conventional method. The following precursors such as FeCl{sub 3}⋅6H{sub 2}O, FeSO{sub 4}⋅7H{sub 2}O, NH{sub 4}OH, and natural zeolite of heulandite type were used in the sample preparation. In this study, the effect of Fe{sub 3}O{sub 4} composition in the composite and microwave time heating were investigated. Fe{sub 3}O{sub 4}/Zeolite nanocomposites were then characterized to study the influence on crystal structures, morphology and physicochemical properties. The characterization techniques include X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen physisorption. The results show that by increasing the microwave heating time, the degree of nanocomposite intergrowth can be enhanced. The nanocomposite was tested in catalytic aquathermolysis of heavy oil at 200°C for 6 h and the Fe{sub 3}O{sub 4}/zeolite of 1 to 4 ratios performed the highest viscosity reduction of heavy oil reaching 92%.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Thermoreflectance Detection of Point Defects Resulting from Focused Ion Beam Milling

Focused ion beam (FIB) milling is a commonly used tool for nanoscale material processing, such as for transmission electron microscopy (TEM) sample preparation, or the creation of fiducial markers prior to other processes and measurements. During milling, a high energy ion beam is used to remove material via sputtering. The expelled target material may return to the sample surface however, affecting subsequent measurements. Beam spreading or irradiation due to neutral gallium may also irradiate a larger area than intended. Extensive research has explored the effects of FIB milling on the prepared TEM sample, but few have looked at the effects of milling on the properties of the sample surrounding the milled region. We use multiple pump-probe laser-based techniques (time domain thermoreflectance and steady-state thermoreflectance) to measure the spatial extent of FIB-induced surface/subsurface changes on a series of silicon wafers milled at multiple currents and doses. We supplement these measurements with high-resolution scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, stylus profilometry, and time-of-flight secondary ion mass spectroscopy. We find a sample surface affected by the FIB up to 1 mm from where milling occurred, with a notable dependence on the ion beam current. We also note remarkably high sensitivity to surface defects using the thermoreflectance metrologies, including detection where other measurements failed.

defects↗
DOE OSTI2015

Development of activated carbon derived from banana peel for CO{sub 2} removal

This research work highlights on the constraints involved in the preparation of the banana peel bio-sorbent, such as impregnation ratio, activation temperature and period of activation for reducing carbon dioxide (CO{sub 2}) in the atmosphere. Micromeritics ASAP 2020 and Field Emission Scanning Electron Microscope (FESEM) were used in identifying the best sample preparation method with the largest surface area which directly contributes to the effectiveness of adsorbent in removing CO{sub 2}. Sample A10 was identified to yield activated carbon with the largest surface area (260.3841 m{sup 2}/g), total pore volume (0.01638 cm{sup 3}/g) and pore diameter (0.2508 nm). Through nitrogen adsorption-desorption isotherm analysis, the existence of sub-micropores was proven when a combination of Type-I and Type-II isotherms were exhibited by the activated carbon produced. The results from the final adsorption test found that the material synthesized from the above mentioned parameter is capable of removing up to 1.65% wt of CO{sub 2} through adsorption at 25°C, suggesting that it can be effectively used as an adsorption material.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Electron microscopy methods in studies of cultural heritage sites

The history of the development and application of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray microanalysis (EDXMA) in studies of cultural heritage sites is considered. In fact, investigations based on these methods began when electron microscopes became a commercial product. Currently, these methods, being developed and improved, help solve many historical enigmas. To date, electron microscopy combined with microanalysis makes it possible to investigate any object, from parchment and wooden articles to pigments, tools, and objects of art. Studies by these methods have revealed that some articles were made by ancient masters using ancient “nanotechnologies”; hence, their comprehensive analysis calls for the latest achievements in the corresponding instrumental methods and sample preparation techniques.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Combined UHV/high-pressure catalysis setup for depth-resolved near-surface spectroscopic characterization and catalytic testing of model catalysts

An ultra-high vacuum (UHV) setup for “real” and “inverse” model catalyst preparation, depth-resolved near-surface spectroscopic characterization, and quantification of catalytic activity and selectivity under technologically relevant conditions is described. Due to the all-quartz reactor attached directly to the UHV-chamber, transfer of the catalyst for in situ testing without intermediate contact to the ambient is possible. The design of the UHV-compatible re-circulating batch reactor setup allows the study of reaction kinetics under close to technically relevant catalytic conditions up to 1273 K without contact to metallic surfaces except those of the catalyst itself. With the attached differentially pumped exchangeable evaporators and the quartz-microbalance thickness monitoring equipment, a reproducible, versatile, and standardised sample preparation is possible. For three-dimensional near-surface sample characterization, the system is equipped with a hemispherical analyser for X-ray photoelectron spectroscopy (XPS), electron-beam or X-ray-excited Auger-electron spectroscopy, and low-energy ion scattering measurements. Due the dedicated geometry of the X-ray gun (54.7°, “magic angle”) and the rotatable sample holder, depth analysis by angle-resolved XPS measurements can be performed. Thus, by the combination of characterisation methods with different information depths, a detailed three-dimensional picture of the electronic and geometric structure of the model catalyst can be obtained. To demonstrate the capability of the described system, comparative results for depth-resolved sample characterization and catalytic testing in methanol steam reforming on PdGa and PdZn near-surface intermetallic phases are shown.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

A Review and Perspective of Recent Bio-Oil Hydrotreating Research

The pathway for catalytic hydrodeoxygenation of biomass derived fast pyrolysis oil represents a compelling route for production of liquid transportation fuels. There has been continued progress and advancements in both the public and private research areas towards driving this technology to completion. Published research and patent literature have demonstrated that continued development of HDO as a part of a processes for production liquid transportation using biomass is being advanced for both fuel blend stocks and for refinery intermediates for co-processing. Much of the research has still focused on “quality” metrics around single or groups of unit operations generating partially treated bio-oil streams without assessing upstream and downstream implications. However, there is an encouraging amount of research that is now being targeted and assessed with attempts to understand the impact on the final fuel product, regardless of the route. Much of the most important research is moving towards continuous, industrially relevant processes where data can be generated to adequately inform process and economic modeling. As the technology for producing liquid transportation fuels from pyrolysis/HDO/coprocessing is driving towards commercialization, further research should be prioritized on the basis of impact to a techno-economic analyses.

bio-oil↗
DOE OSTI2012

Hybrid opto-electric techniques for molecular diagnostics

Hybrid optoelectric techniques reflect a new paradigm in microfluidics. In essence, these are microfluidic techniques that employ a synergistic combination of optical and electrical forces to enable noninvasive manipulation of fluids and/or particle-type entities at the micro/nano-scale [1]. Synergy between optical and electrical forces bestows these techniques with several unique features that are promising to bring new opportunities in molecular diagnostics. Within the scope of molecular diagnostics, several aspects of optoelectric techniques promise to play a relevant role. These include, but are not limited to, sample preparation, sorting, purification, amplification and detection.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2014

A diamond-based scanning probe spin sensor operating at low temperature in ultra-high vacuum

We present the design and performance of an ultra-high vacuum (UHV) low temperature scanning probe microscope employing the nitrogen-vacancy color center in diamond as an ultrasensitive magnetic field sensor. Using this center as an atomic-size scanning probe has enabled imaging of nanoscale magnetic fields and single spins under ambient conditions. In this article we describe an experimental setup to operate this sensor in a cryogenic UHV environment. This will extend the applicability to a variety of molecular systems due to the enhanced target spin lifetimes at low temperature and the controlled sample preparation under UHV conditions. The instrument combines a tuning-fork based atomic force microscope (AFM) with a high numeric aperture confocal microscope and the facilities for application of radio-frequency (RF) fields for spin manipulation. We verify a sample temperature of <50 K even for strong laser and RF excitation and demonstrate magnetic resonance imaging with a magnetic AFM tip.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Ramdb: The NASA Raman Spectral Database (version 1.00).

Given that, in most instances, minimal sample preparation is required and due to its contactless instrument design, Raman spectroscopy is one of the most versatile vibrational spectroscopic techniques for the chemical analysis of environmental and biological specimens. The diversity of applications of Raman spectroscopy ranges anywhere from art [1] to planetary science missions [2]. The advancement in the use of Raman spectroscopy in Solar System missions, notably in post-mission sample return analysis, requires a spectral library holding the broad range of specimens that could be found in Solar System sources. For this purpose, we have initiated the development of a Raman spectral database (Ramdb) at NASA Ames Research Center. Currently, the database includes experimental and theoretical Raman spectra of PAHs [3, 4], as well as laboratory Raman spectra of amino acids, carbon allotropes, minerals, and analogs relevance to Earth Sciences [5], Exobiology [6], Planetary [7], and Astrochemistry [8] to name just a few examples. Ramdb can be found on the web at www.astrochemistry.org/ramdb, where raw and processed Raman spectra can be downloaded in CSV format. The laboratory Raman spectra are measured using a laser Raman spectrometer (JASCO NRS-5500-532QRI). The Raman instrument is equipped with three excitation lasers, with wavelengths of 405, 532, and 785 nm. A clean silicon substrate is used as the internal standard for wavenumber calibration. Powdered samples were prepared (microscopic >10 um, grounded microscopic < 10 um) on glass slides. Some raw data exhibited a background signal arising as a combination of laser-induced fluorescence from the sample. To correct this background, we developed a Python pipeline that uses open-source Python libraries. Ramdb provides both raw and processed (using Python pipeline) data, which includes tabulated Raman shift transitions and other measurement details. The theoretical Raman band positions of PAHs (pyrene monomers and tetramer clusters) were computed using density functional theory (DFT) with the help of the Gaussian 16 suite of programs [9]. In the near future, Ramdb will serve as a repository of Raman spectral data from Laboratory Astrophysics and Planetary Science experiments involving the irradiation of organic compounds under simulated space and planetary conditions. In addition, online and offline tools will be developed for utilising the database for comparison to the user’s sample.

N Punnakayathil↗
DOE OSTI2018

Optical Methods for Identifying Hard Clay Core Samples During Petrophysical Studies

X-ray phase analysis of the general mineralogical composition of core samples from one of the West Siberian fields was performed. Electronic absorption spectra of the clay core samples with an added indicator were studied. The speed and availability of applying the two methods in petrophysical laboratories during sample preparation for standard and special studies were estimated.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Stable-carbon isotope ratios for sourcing the nerve-agent precursor methylphosphonic dichloride and its products

The ability to connect a chemical threat agent to a specific batch of a synthetic precursor can provide a fingerprint to contribute to effective forensic investigations. Stable isotope analysis can leverage intrinsic, natural isotopic variability within the molecules of a threat agent to unlock embedded chemical fingerprints in the material. Methylphosphonic dichloride (DC) is a chemical precursor to the nerve agent sarin. It is converted to methylphosphonic difluoride (DF) as part of the sarin synthesis process. We used a suite of commercially available DC stocks to both evaluate the potential for δ13C analysis to be used as a fingerprinting tool in sarin-related investigations and to develop sample preparation techniques (using chemical hydrolysis) that can simplify isotopic analysis of DC and its synthetic products. We demonstrate that natural isotopic variability in DC results in at least three distinct, isotope-resolved clusters within the thirteen stocks we analyzed. Isotopic variability in the carbon feedstock (i.e., methanol) used for DC synthesis is likely inherited by the DC samples we measured. We demonstrate that the hydrolysis of DC and DF to methylphosphonic acid (MPA) can be used as a preparative step for isotopic analysis because the reaction does not impart a measureable isotopic fractionation. MPA is more chemically stable, less toxic, and easier to handle than DC or DF. Further, the hydrolysis method we demonstrated can be applied to a suite of other precursors or to sarin itself, thereby providing a potentially valuable forensic tool.

Moran, James J.↗
DOE OSTI2018

Laboratory synthesis of C3S on the kilogram scale

An optimized process using amorphous silica for efficient C{sub 3}S synthesis in the laboratory is reported: an estimated production capacity of ~2 kg C{sub 3}S within a week is possible. Amorphous silica (fumed silica) was used as raw material and inter-ground with CaCO{sub 3} and water for C{sub 3}S synthesis, the dried raw mixture has sufficient green strength to be self-supporting, which allows large cylinders to be placed in Platinum crucibles. The mineral composition of the sintered sample was quantified with X-ray powder diffraction using Rietveld analysis. C{sub 3}S with 3 S synthesis was dramatically enhanced because of 1) increased burnability of the raw mix due to amorphous silica and very fine CaCO{sub 3} particles after grinding, 2) simplified sample preparation process avoiding pressing discs and 3) improved capacities of the crucible and furnace.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Chapter 4.2 - Preparation of nanoparticles for surface analysis

A variety of methods used to prepare nano-objects for surface analysis are described along with information about when they might be best applied. Intrinsic properties of NPs that complicate their characterization and need to be considered when planning for surface or other analyses of NPs are identified, including challenges associated with reproducible synthesis and functionalization of the particles as well as their dynamic nature. Information about the sample preparation processes, along with analysis data, that need to be added to the collection of material provenance information is identified and examples of protocols that have been successfully used for preparation of nano-objects for surface analysis are included in an annex.

characterization challenges↗
DOE OSTI2012

Test Results from Gamma Irradiation of Aluminum Oxyhydroxides

Hydrated metal oxides or oxyhydroxides boehmite and gibbsite that can form on spent aluminum-clad nuclear fuel assemblies during in-core and post-discharge wet storage were exposed as granular powders to gamma irradiation in a 60 Co irradiator in closed laboratory test vessels with air and with argon as separate cover gases. The results show that boehmite readily evolves hydrogen with exposure up to a dose of 1.8 x 10 8 rad, the maximum tested, in both a full-dried and moist condition of the powder, whereas only a very small measurable quantity of hydrogen was generated from the granular powder of gibbsite. Specific information on the test setup, sample characteristics, sample preparation, irradiation, and gas analysis are described.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2018

Effect of Restricted Geometry on the Structure and Phase Transitions in Potassium Nitrate Nanoparticles

The effect of restricted geometry and thermal prehistory of sample preparation on phase transitions in nanocomposites on base of porous glasses with average pore diameters 7 and 46 nm filled by potassium nitrate have been studied by X-rays and neutron diffraction. The nanoparticle sizes have been determined and phase diagrams (on cooling) for these nanoparticles have been described. It is shown that there is a critical nanoparticle size in the interval from 30 till 20 nm, at which in nanocomposite the ferroelectric phase is realized only regardless of preparation method.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Excess Conductivity Investigation of Y{sub 3}Ba{sub 5}Cu{sub 8}O{sub 18±δ} Superconductors Prepared by Various Parameters of Planetary Ball Milling Technique

Superconducting samples of type Y{sub 3}Ba{sub 5}Cu{sub 8}O{sub 18±δ} were elaborated by using a planetary high-energy ball milling (HEBM) technique with various parameters. Phases, microstructure, and superconductivity have been examined using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electrical resistivity measurements. SEM investigation shows the occurrence of nanoentities embedded into the superconducting matrix for samples prepared by a ball milling technique. The main objective of this study is to investigate the influence of ball milling parameters on the fluctuation-induced conductivity (FIC). The electrical resistivity versus temperature, ρ(T), above T{sub c} was analyzed using Lawrence–Doniach (LD) and Aslamazov–Larkin (AL) models. Different fluctuation regimes indicated by short-wave fluctuation (SWF) and three-dimensional (3D), two-dimensional (2D), one-dimensional (1D), and critical region (CR) fluctuations were identified. The coherence length at zero temperature, the effective layer thickness, the critical magnetic fields, and the critical current densities are determined. The superconducting parameters strongly depend on the planetary ball milling technique, and the results are explained in relevancy to the microstructure. It was found that the achievement of a microstructure with well-dispersed nanoentities is an effective way for introducing pinning centers for enhancing critical current density and flux pinning capability of bulk Y-358.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2017

Rapid method to determine 226Ra in steel samples

The rapid measurement of 226 Ra in steel samples is very important in the event of a radiological emergency. 226 Ra (T 1/2 = 1600 y) is a natural radionuclide present in the environment and a highly toxic alpha-emitter. Due to its long life and tendency to concentrate in bones, 226 Ra ingestion or inhalation can lead to significant committed dose to individuals. A new method for the determination of 226 Ra in steel samples has been developed at the Savannah River Environmental Laboratory. The new method employs a rugged acid digestion method that includes hydrofluoric acid, followed by a single precipitation step to rapidly preconcentrate the radium and remove most of the dissolved steel sample matrix. Radium is then separated using a combination of cation exchange and extraction chromatography, and 226 Ra is measured by alpha spectrometry. This approach has a sample preparation time of ~ 8 h for steel samples, has a very high tracer yield (> 88%), and removes interferences effectively. A 133 Ba yield tracer is used so that samples can be counted immediately following the separation method, avoiding lengthy ingrowth times that are required in other methods.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2024

Direct observation of twisted stacking domains in the van der Waals magnet CrI 3

Van der Waals (vdW) stacking is a powerful technique to achieve desired properties in condensed matter systems through layer-by-layer crystal engineering. A remarkable example is the control over the twist angle between artificially-stacked vdW crystals, enabling the realization of unconventional phenomena in moiré structures ranging from superconductivity to strongly correlated magnetism. Here, we report the appearance of unusual 120° twisted faults in vdW magnet CrI 3 crystals. In exfoliated samples, we observe vertical twisted domains with a thickness below 10 nm. The size and distribution of twisted domains strongly depend on the sample preparation methods, with as-synthesized unexfoliated samples showing tenfold thicker domains than exfoliated samples. Cooling induces changes in the relative populations among different twisting domains, rather than the previously assumed structural phase transition to the rhombohedral stacking. The stacking disorder induced by sample fabrication processes may explain the unresolved thickness-dependent magnetic coupling observed in CrI 3 .

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗