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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 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Development of Material Studies at the LANL UCN Facility Focusing on Actinide Hydriding and Fission Damage

The aging of as-built actinide surfaces in static and dynamic environments is a complex problem of high importance to LANL’s core mission. Many standard material science tools used to study this problem are ideal for highly controlled, lab-made samples. The goal of this work is to use ultracold neutrons to bridge the gap between lab made and as-built surface aging studies. This capability is unique to LANL and will support our core mission.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Investigating Soil Organic Matter Complexation using Spectral Induced Polarization

Spectral induced polarization (SIP) laboratory experiments were conducted to determine the sensitivity of this method to the formation of soil organic matter (SOM) complexes, with a long-term goal of field-scale monitoring. There are few SIP experiments that have explored this topic, yet understanding the dynamic behavior and interactions of SOM at the field scale could provide insight into soil fertility and health which influences crop yields, microorganisms that degrade organic pollutants, and carbon stabilization. We present the results of three experiments where the iron oxide, ferrihydrite (Fhy), was used to coat different media, and then the OM compound pentaglycine (PG) was pulse injected to form SOM complexes. SIP data was collected during these injections to capture any surface complexation changes. These experiments were performed in 1) a fluidic cell containing a micromodel, 2) a column containing Fhy coated ceramic beads and 3) a column containing Fhy coated Accusand®. Our results show a higher frequency response (defined here as > 1 Hz) in all three experiments, with the largest amplitude response after the first PG injection (Figure S.1). The repeatability of this response is encouraging and supporting data collected on the Accusand® experiment provides preliminary insight into the mechanisms controlling the SIP signatures. Sampling of fluid conductivity $σ_w$ and pH may indicate deprotonation of SOM occurring or rapid adsorption and release of protons from the Fhy sites. However additional experiments are needed to identify and confirm the primary and secondary reactions impacting the SIP response. We are looking towards other opportunities to continue this work, particularly to repeat experiments while collecting supporting datasets.

58 GEOSCIENCES↗
DOE OSTI2019

The Preparation and Characterization of Co–Ni Nanoparticles and the Testing of a Heterogenized Co–Ni/Alumina Catalyst for CO Hydrogenation

Samples of well-controlled nanoparticles consisting of alloys of cobalt and nickel of different atomic ratios were synthesized using wet chemical methods with oleylamine as the solvent and the reducing agent. These materials were characterized by a variety of techniques, including high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Small amounts of heterogenized catalysts were prepared using alumina as the support. However, the potential for use of Co–Ni catalysts in CO hydrogenation was explored using a larger amount of Co–Ni/alumina catalyst prepared from standard aqueous impregnation methods and tested in a continuously stirred tank reactor (CSTR) for Fischer–Tropsch synthesis (FTS). Results are compared to a reference catalyst containing only cobalt. The heterogenized catalysts were characterized using synchrotron methods, including temperature programmed reduction with extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge spectroscopy (TPR-EXAFS/XANES). The characterization results support intimate contact between Co and Ni, strongly suggesting alloy formation. In FTS testing, drawbacks of Ni addition included decreased CO conversion on a per gram catalyst basis, although Ni did not significantly impact the turnover number of cobalt, and produced slightly higher light gas selectivity. Benefits of Ni addition included an inverted induction period relative to undoped Co/Al2O3, where CO conversion increased with time on-stream in the initial period, and the stabilization of cobalt nanoparticles at a lower weight % of Co.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Evaluation of High-Temperature Martensitic Steels for Heavy-Duty Diesel Piston Applications

Five different commercially available high-temperature martensitic steels were evaluated for use in a heavy-duty diesel engine piston application and compared to existing piston alloys 4140 and microalloyed steel 38MnSiVS5 (MAS). Finite element analyses (FEA) were performed to predict the temperature and stress distributions for severe engine operating conditions of interest, and thus aid in the selection of the candidate steels. Complementary material testing was conducted to evaluate the properties relevant to the material performance in a piston. The elevated temperature strength, strength evolution during thermal aging, and thermal property data were used as inputs into the FEA piston models. Additionally, the long-term oxidation performance was assessed relative to the predicted maximum operating temperature for each material using coupon samples in a controlled-atmosphere cyclic-oxidation test rig. A current commercial steel piston alloy, quenched and tempered martensitic steel 4140, was tested in a single-cylinder research engine for a baseline oxidation and mechanical performance assessment using an abbreviated (50h) durability test plan. The predicted suitability of a candidate piston material in an engine is primarily based on its elevated temperature strength, oxidation resistance, and the complex influence of thermal conductivity, the latter of which is substantially lower for the candidate materials considered in this research relative to the traditional alloys. Although the lower thermal conductivity causes the candidate alloys to operate in higher temperature ranges under identical engine operating conditions and piston geometries, increasing the likelihood of partially or completely negating their strength and oxidation resistance advantages relative to 4140 and MAS steels, this evaluation indicates that several of the candidate piston alloys are predicted to enable improved oxidation resistance under more severe engine operating conditions relative to the current piston materials. However, further evaluation is required to determine if the elevated temperature fatigue strength and durability of these alloys are suitable for more severe engine conditions.

36 MATERIALS SCIENCE↗
NASA NTRS1966

Marine Biology, volume II

Symposium on marine biology - growth rate, cycles, transportation, photosynthesis, distribution, sampling, nutrition, and light control of natural phytoplankton ecological systems

CONFERENCE↗
NASA NTRS1972

Magnetic properties of Apollo 14 breccias and their correlation with metamorphism.

The magnetic properties of Apollo 14 breccias can be explained in terms of the grain size distribution of the interstitial iron which is directly related to the metamorphic grade of the sample. In samples 14049 and 14313 iron grains less than 500 A in diameter are dominant as evidenced by a Richter-type magnetic aftereffect and hysteresis measurements. Both samples are of lowest metamorphic grade. The medium metamorphic-grade sample 14321 and the high-grade sample 14312 both show a logarithmic time-dependence of the magnetization indicative of a wide range of relaxation times and thus grain sizes, but sample 14321 contains a stable remanent magnetization whereas sample 14312 does not. This suggests that small multidomain particles (less than 1 micron) are most abundant in sample 14321 while sample 14312 is magnetically controlled by grains greater than 1 micron. The higher the metamorphic grade, the larger the grain size of the iron controlling the magnetic properties.

Gose, W. A.↗
NASA NTRS1974

Furnace systems development

Space processing facilities, including furnace systems, will, only vaguely resemble their laboratory and industry counterparts. Within the constraints imposed by the host vehicle, flight furnaces will be more versatile. They will provide a wider range of controlled heating, cooling and sample positioning to accommodate the requirements of experiment scientists, and will be more efficiently packaged. The development of these advanced furnace systems will be an essential element in the orderly evolution of space processing technology.

Aldrich, B. R.↗
NASA NTRS1976

Introducing controlled matter into a fluid system

Device consisting of capsule holder and glass inner tube has been developed to handle controlled particulate-contamination samples. Premeasured quantity of particles can be injected into closed fluid system without contamination.

Hoffman, C. E.↗
NASA NTRS1976

Banning artwork program user's manual

A manual containing computer programs for designing circuits is presented. A description of the pattern library, the plotter used to draw the circuit patterns, and program control cards is given. Sample printouts and cards are shown.

Taylor, J. F.↗
NASA NTRS1976

Thermomagnetic analysis of meteorites. III - C3 and C4 chondrites

Results are presented for thermomagnetic analysis in a controlled oxygen atmosphere of samples from thirteen C3 chondrites and two C4 chondrites. The examined meteorites are found to have rather diverse thermomagnetic properties, so they are placed into three groups on the basis of their thermomagnetic behavior and magnetic mineralogy: (1) those possibly containing magnetite before heating, but which display a large increase in saturation moment upon cooling to room temperature; (2) those containing magnetite as their major magnetic phase, but which show little change in saturation moment following the heating-cooling cycle; and (3) those which contain iron metal in addition to other magnetic phases. Upper limits are placed on the magnetite content of the five meteorites in group 1 by assuming that the initial saturation moment is due entirely to magnetite, and quantitative estimates of the magnetite content of the four meteorites in group 2 are determined from ambient-temperature saturation magnetization measurements. The data for the six meteorites in group 3 are discussed in terms of nickel content and troilite oxidation. It is concluded that since the magnetic and bulk mineralogies of carbonaceous chondrites are more varied and complex than indicated by whole-rock elemental analyses, the origin of such meteorites cannot be described by a simple model.

Herndon, J. M.↗
NASA NTRS1978

Applications and limitations of very large-scale integration in SAR azimuth processing

The major limitation of a convolution processor designed with CCD memory chips is the inability to operate in real time except for slow aircraft speeds or coarse resolutions. Two methods of summing the products were evaluated with respect to speed, power, and space requirements. A convolution processor was designed, and the number of chips as well as the power and volume requirements were determined using 4, 6, and 8 bit data words. The processor is flexible because range samples may be traded for additional azimuth samples by altering the control signals. The processor is also modular, and additional range or azimuth may be processed by adding more cards.

Kuhler, D. G.↗
NASA NTRS1979

Thermal analyses of a materials processing furnace being developed for use with heat pipes

A special materials processing furnace is being developed for the forthcoming Spacelab missions to study the solidification under closely controlled conditions of various sample materials in the absence of gravity. The samples are to be rod shaped and subjected to both heating and cooling simultaneously. The thermal model is based on a developed Thermal Analyzer computer program. The model was developed to be very general to enable the simulation of variations in the furnace design and, hence, serve as an aid in finalizing the design. The thermal model is described and a user's guide given. Some preliminary results obtained in testing the model are also given.

Mcanally, J. V.↗
NASA NTRS1983

Digital Single-Phase Power-Factor Controller

Digital circuit has faster response to load changes. Digital power-factor controller senses changing motor-load torques by sampling open-circuit voltage across gate-controlled silicon switch. Circuit responds more rapidly to hanging loads than analog power-factor controllers because no low-pass filter is in feedback loop.

Dabney, R. W.↗
NASA NTRS1984

Monitoring Lignin Content in Paper Processing

Feedstock and finished pulp analyzed and controlled automatically. System acquires samples from feed hopper, digestor, and blow tank. Sample homogenized, washed, and dried while conveyed to flash pyrolyzer. In pyrolyzer material converted into basic constituent, mostly compounds of molecular weight less than 200.

Boettger, H. G.↗
NASA NTRS1983

Modified timing module for Loran-C receiver

Hardware documentation is provided for the modified LORAN-C timing module, which uses interrupt-driven software control in determining loop sample times. Computer loading is reduced by eliminating polled operation of the timing loop.

Lilley, R. W.↗