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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Experiment definition phase shuttle laboratory: LDRL-10.6 experiment

Progress is reported in the development of the space shuttle laboratory laser data relay link. The system transmittance of various surfaces was considered in order to examine the coating tradeoffs for the beryllium mirrors. The results of six coating combinations considered are summarized. It is recommended that silver coatings be used throughout the system. Design of the pre-expander and a preliminary alignment procedure implemented to align all optical elements to the reference mechanical axis (the rotational axis of the outer gimbal bearing located between the two Gregorian telescopes) are included. The local oscillator subsystem, consisting of the laser, Stark cell, Stark cell electronics, power supply, starting circuit, and conditioning optics were completed and installed in the optimechanical subsystem and operation against a 10.6 micrometer source was attempted. Preliminary measurements of the HgCdTe mixer showed that this critical element was inoperative and in subsequent tests the receiver front end electronics had also failed. Possible reasons for these failures and corrective action and steps to prevent future recurrence are discussed.

Source record↗
NASA NTRS1973

Zero-gravity cloud physics laboratory: Candidate experiments definition and preliminary concept studies

The candidate definition studies on the zero-g cloud physics laboratory are covered. This laboratory will be an independent self-contained shuttle sortie payload. Several critical technology areas have been identified and studied to assure proper consideration in terms of engineering requirements for the final design. Areas include chambers, gas and particle generators, environmental controls, motion controls, change controls, observational techniques, and composition controls. This unique laboratory will allow studies to be performed without mechanical, aerodynamics, electrical, or other type techniques to support the object under study. This report also covers the candidate experiment definitions, chambers and experiment classes, laboratory concepts and plans, special supporting studies, early flight opportunities and payload planning data for overall shuttle payload requirements assessments.

Eaton, L. R.↗
NASA NTRS1974

Experiment definition phase shuttle laboratory LDRL 10.6 experiment

System optimization is reported along with mission and parameter requirements. Link establishment and maintenance requirements are discussed providing an acquisition and tracking scheme. The shuttle terminal configurations are considered and are included in the experiment definition.

Source record↗
NASA NTRS1975

Experiment definition phase shuttle laboratory LDRL-10.6 experiment

The acquisition and tracking links of shuttle to molniya satellite and shuttle to ground are established. Link parameters and tolerance are analyzed. A 10-micromillimeter optomechanical subsystem brassboard model was designed and measured for optical properties and weight optimization. The design incorporates an afocal rotating Gregorian telescope in a two-gimbal berylium structure with beam steering control mechanisms. Parameters for both the optomechanical subsystem and spaceborne terminals are included.

Source record↗
NASA NTRS1975

Experiment definition phase shuttle laboratory LDRL-10.6 experiment

The 10.6 microns laser data relay link (LDRL 10.6) program was directed to applying optical communications to NASA's wideband data transmission requirements through the 1980's. The LDRL consists of a transmitter on one or more low earth orbit satellites with an elliptical orbit satellite receivers. Topics discussed include: update of the LDRL design control table to detail the transmitter optical chain losses and to incorporate the change to a reflective beam pre-expander; continued examination of the link establishment sequence, including its dependence upon spacecraft stability; design of the transmitter pointing and tracking control system; and finalization of the transmitter brassboard optical and mechanical design.

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NASA NTRS1993

Carbonate formation on Mars: Latest experiments

Laboratory simulations of Martian CO2 storage address whether carbonate formation could have reduced CO2 pressure from a hypothetical greater than 1 bar to the present 7 mbar in less than or equal to 3 to 4 billion years. This problem is addressed with experiments and analysis designed to verify and improve previous kinetic measurements, reaction mechanisms, and product characterizations, with the goal of improving existing models of Martian CO2 history. A sensitive manometer monitored the pressure drop of CO2 due to uptake by powdered silicate for periods of 3 to 100+ days. Pressure drops for diopside 1 and basalt show rapid short-term (approximately one day) CO2 uptake and considerably slower long-term pressure drops. Curves for diopside 2, olivine 1, and olivine 2 are qualitatively similar to those for diopside 1, whereas quartz and plagioclase show near-zero short-term pressure drops and very slow long-term signals, indistinguishable from a leak (less than 10(exp 11) mol/sq m/s).

Stephens, S. K.↗
NASA NTRS1992

Joint Langley Research Center/Jet Propulsion Laboratory CSI experiment

This paper describes a joint Control Structure Interaction (CSI) experiment in which Jet Propulsion Laboratory (JPL) damping devices were incorporated into the Langley Research Center (LaRC) Phase 0 Testbed. The goals of the effort were twofold: (1) test the effectiveness of the JPL structural damping methods in a new structure and (2) assess the feasibility of combining JPL local control methods with the LaRC multiple input multiple output global control methods. Six dampers (2 piezoelectric active members, 4 viscous dampers), placed in three different regions of the structure, produced up to 26 dB attenuation in target modes. The combined control strategy in which the JPL damping methods contributed local control action and the LaRC control scheme provided global control action, produced and overall control scheme with increased stability margins and improved performance. This paper presents an overview of the technologies contributed from the two centers, the strategies used to combine them, and results demonstrating the success of the damping and cooperative control efforts.

Neat, Gregory W.↗
NASA NTRS1992

Optical and TEM study of shock metamorphism from the Sedan test site

Thus far, detailed petrologic studies of shock metamorphism have been performed on samples recovered from laboratory experiments and on a few natural impactites. The loading history of these samples is quite different: In particular, laboratory experiments spend only a short time (less than 1 microsec) at peak pressure, whereas natural impactites may have stress pulses from 0.1 - 1 ms. On the other hand, laboratory experiments have known stress histories; natural impactites do not. Natural samples are also subjected to thousands or millions of years of postshock annealing and/or weathering. A useful intermediate case is that of nuclear detonation. Stress pulses for these events can reach 0.1 ms or higher, and samples are obtained in pristine condition. All three types of loading produce stresses of hundreds of kilobars. Samples studied were taken from the Sedan nulcear test site, and consist of a coarse-grained granodiorite containing quartz, K-feldspar, cordierite, and hornblende. Samples were studied optically in this section, then were thinned with an ion mill and studied by transmission electron microscopy (TEM). Optically, quartz and K-feldspar displayed numerous sets of planar deformation features (PDF's) identical to the nondecorated PDF's seen in laboratory samples and many natural impactites. TEM study showed that the PDF's in quartz and feldspar corresponded to densely packed wide transformation lamellae identical to those described in laboratory studies. The transformation lamellae in both minerals were amorphous, with no sign of high-pressure phases. In the case of K-feldspar only, narrow sublamellae extended outward from some wide lamellae. Quartz, which was more abundant and studied more extensively, contained no shock-induced dislocations. Some planar features were also seen in cordierite, but could not be identified due to rapid beam damage. No shock defects were seen in hornblende in TEM. The shock-induced defects present at the Sedan site are very similar to those seen in shock recovery experiments, and also to those present at certain natural events (e.g., Meteor Crater). This suggests that shock deformation in quartz is not strongly dependent on shock pulse duration, and that laboratory recovery experiments are useful simulations of natural impact events.

Gratz, A. J.↗
DOE OSTI2024

Pore architecture controls on mineral reactivity

Mineral dissolution rates measured in natural environments are much slower than those measured in laboratory settings. This project tested the hypothesis that the way fluid flows through rocks in natural systems creates areas where mineral dissolution is fast and areas where mineral dissolution is slow. This hypothesis was tested with a combination of laboratory experiments and numerical simulation. We demonstrated a separation of fluid flow pathways and rates of mineral dissolution in laboratory experiments for the first time using an experimental approach where we created synthetic rocks that have different ratios of connected and dead-end pathways for fluid flow. In laboratory experiments with higher proportions of dead-end pathways, the mineral dissolution rates were slower. We found that where fluid flows through connected pathways the continuous refreshing of fluid at the mineral surface creates conditions where dissolution is fast. In contrast, where fluid either flows slowly through poorly connected pathways or is stagnant in dead-end pathways, mineral dissolution is slow. The results from this project suggest that the overall slowing of rates of mineral dissolution is important when the proportion of dead-end pathways is greater than ~40%. This project informs our understanding of the way that fluids react with rocks in carbon dioxide sequestration and enhanced geothermal projects where fluids are purposefully injected into rocks for energy applications.

58 GEOSCIENCES↗
NASA NTRS1984

Tropospheric sources of NOx: lightning and biology

Laboratory experiments to quantify the global production of NOx (NO + NO2) in the troposphere due to atmospheric lightning and biogenic activity in soil are presented. These laboratory experiments, as well as other studies, suggest that the global production of NOx by lightning probably ranges between 2 and 20 MT(N)y-1 of NO and is strongly dependent on the total energy deposited by lightning, a quantity not well-known. In our laboratory experiments, nitrifying micro-organisms is soil were found to be a significant source of both NO and nitrous oxide (N2O). The measured production ratio of NO to N2O averaged 2-3 for oxygen partial pressures of 0.5-10%. Extrapolating these laboratory measurements to the global scale, which is somewhat risky, suggests that nitrifying micro-organisms in soil may account for as much as 10 MT(N) y-1 of NO. Additional experiments with denitrifying micro-organisms gave an NO to N2O production ratio ranging from 2 to 4 for an oxygen partial pressure of 0.5% and a ratio of less than unity for oxygen partial pressures ranging from 1 to 20%. The production of NO and N2O, normalized with respect to micro-organism number indicates that the production of both NO and N2O by denitrifying micro-organisms is at least an order of magnitude less than production by nitrifying micro-organisms for the micro-organisms studied.

Atmosphere/chemistry↗
NASA NTRS1992

Effect of impact angle on central-peak/peak-ring formation and crater collapse on Venus

Although asymmetry in ejecta patterns and craters shape-in-plan are commonly cited as diagnostic features of impact angle, the early-time transfer of energy from impactor to target also creates distinctive asymmetries in crater profile with the greatest depth uprange. In order to simulate gravity-controlled crater-growth, laboratory experiments use loose particulate targets as analogs for low-strength material properties following passage of the shock. As a result, impact crater diameter D in laboratory experiments generally is many times greater than the impactor diameter 2r (factor of 40), and early-time asymmetries in energy transfer from oblique impacts are consumed by subsequent symmetrical crater growth, except at the lowest angles (less than 25 deg). Such asymmetry is evident for oblique (less than 60 deg from horizontal) impacts into aluminum where D/2r is only 2 to 4. Because cratering efficiency decreases with increasing crater size and decreasing impact angle, large scale planetary craters (4080 km) should have transient excavation diameters only 6-10 times larger than the impactor. At basin scales, D/2r is predicted to be only 3-5, i.e., approaching values for impacts into aluminum in laboratory experiments. As a result, evidence for early-time asymmetry in impactor energy transfer should become evident on planetary surfaces, yet craters generally retain a circular outline for all but the lowest impact angles.

Schultz, Peter H.↗
DOE OSTI2024

Simulation of Particulate Transport for Delivery of Solid Amendments into the Subsurface: FY24 Status Report

For particulate-based amendments to be viable for field-scale remediation at the Hanford Site (e.g., 200 DV-1 Operable Unit), particles need to be delivered a sufficient radial distance from an injection well and retained at concentrations high enough for effective treatment. An accurate description of the particle radius of influence (ROI) is critical for developing an overall remediation strategy. However, field-scale particle simulations are currently limited due to insufficient simulation capabilities and a lack of experimental data to validate and parameterize particle transport models. To help build toward field-scale deployment, this fiscal year (FY) we have (1) developed a pre screening tool to estimate particle transport, (2) implemented particle transport models within PFLOTRAN, and (3) conducted preliminary estimations of particle ROI. While field-scale numerical simulations will ultimately be necessary before remedy design and field implementation, we have developed a pre-screening tool that offers valuable estimations of expected particle injectability and ROI in a 1-D system. The advantage of the tool is that it does not require extensive laboratory experiments and instead makes predictions based solely on routine laboratory measurements. This tool can assist in down-selection and decision-making by identifying which particle amendment systems are worth pursuing in future laboratory experiments, such as 1-D column tests and beyond. With any system, scaling up from the lab to the field presents challenges. Currently, there is no field data available for model calibration or validation. However, the theoretical particle models being developed herein are the best tools available to guide progress toward field deployment. To help bridge this gap and verify model predictions, larger-scale lab experiments are being proposed. To advance simulation capabilities, six particle transport models are being integrated into the reactive transport simulator PFLOTRAN. These include colloid filtration theory (CFT) and five additional particle transport models (M1-M5). Each model, from M1 to M5, progressively incorporates additional particle transport and retention processes. Ultimately, the simplest model capable of accurately describing 1-D column data will be selected and parameterized. During FY24, the CFT and M1 model have been fully implemented within PFLOTRAN. Using an existing 1 D column experiment, the two currently implemented particle transport models (CFT and M1), and associated parameters, were fit to this experiment. While simpler model formulations are helpful for estimations, these formulations could not fully describe particle transport and retention behavior in the previous 1-D column experiment. Thus, additional complexities will need to be considered, which will be accounted for in the M2-M5 model formulations. Additionally, because a viscous, shear thinning fluid was required to keep particles in suspension, considerations for flow will also need to also be accounted for. Therefore, a new immiscible two-phase flow mode is currently being implemented in PFLOTRAN. With some modifications, this new flow module could also support simulation of non-Newtonian liquid amendments, foams, and emulsions. We also estimated the expected ROI of solid amendments using 1-D simulations. The average predicted ROI was approximately 15 ft for micron-sized zero valent iron (mZVI) suspended in xanthan gum (XG). Using the pre screening tool and ROI estimates, additional amendment-delivery laboratory characterization and experiments are proposed. The results from additional experiments can be used to validate and parametrize particulate transport model formulations, which will ultimately provide predictive capabilities for field amendment-delivery systems.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2001

The UAH Spinning Terrella Experiment: A Laboratory Analog for the Earth's Magnetosphere

The UAH Spinning Terrella Experiment has been modified to include the effect of a second magnet. This is a simple laboratory demonstration of the well-known double-dipole approximation to the Earth's magnetosphere. In addition, the magnet has been biassed $\sim$-400V which generates a DC glow discharge and traps it in a ring current around the magnet. This ring current is easily imaged with a digital camera and illustrates several significant topological properties of a dipole field. In particular, when the two dipoles are aligned, and therefore repel, they emulate a northward IMF Bz magnetosphere. Such a geometry traps plasma in the high latitude cusps as can be clearly seen in the movies. Likewise, when the two magnets are anti-aligned, they emulate a southward IMF Bz magnetosphere with direct feeding of plasma through the x-line. We present evidence for trapping and heating of the plasma, comparing the dipole-trapped ring current to the cusp-trapped population. We also present a peculiar asymmetric ring current produced in by the plasma at low plasma densities. We discuss the similarities and dissimilarities of the laboratory analog to the collisionless Earth plasma, and implications for the interpretation of IMAGE data.

Sheldon, R. B.↗
DOE OSTI2021

Verification of Coupled Hydraulic Fracturing Simulators Using Laboratory-Scale Experiments

In this work, we aim to verify the predictions of the numerical simulators, which are used for designing field-scale hydraulic stimulation experiments. Although a strong theoretical understanding of this process has been gained over the past few decades, numerical predictions of fracture propagation in low-permeability rocks still remains a challenge. Against this background, we performed controlled laboratory-scale hydraulic fracturing experiments in granite samples, which not only provides high-quality experimental data but also a well-characterized experimental set-up. Using the experimental pressure responses and the final fracture sizes as benchmark, we compared the numerical predictions of two coupled hydraulic fracturing simulators—CSMP and GEOS. Both the simulators reproduced the experimental pressure behavior by implementing the physics of Linear Elastic Fracture Mechanics (LEFM) and lubrication theory within a reasonable degree of accuracy. The simulation results indicate that even in the very low-porosity (1–2 %) and low-permeability (10 -18 m 2 - 10 -19 m 2 ) crystalline rocks, which are usually the target of EGS, fluid-loss into the matrix and unsaturated flow impacts the formation breakdown pressure and the post-breakdown pressure trends. Therefore, underestimation of such parameters in numerical modeling can lead to significant underestimation of breakdown pressure. The simulation results also indicate the importance of implementing wellbore solvers for considering the effect of system compressibility and pressure drop due to friction in the injection line. The varying injection rate as a result of decompression at the instant of fracture initiation affects the fracture size, while the entry friction at the connection between the well and the initial notch may cause an increase in the measured breakdown pressure.

15 GEOTHERMAL ENERGY↗
DOE OSTI2020

Formation and Diagnostics of Collisionless Shocks in Laser-Produced Plasmas (Final Report)

Collisions of supersonic flows occur frequently in astrophysics, and the resulting shock waves are responsible for the properties of many astrophysical phenomena, such as supernova remnants, Gamma Ray Bursts and jets from Active Galactic Nuclei. Because of the low density of astrophysical plasmas, the mean free path due to Coulomb collisions is typically very large; therefore, most shock waves in astrophysics are “collisionless” and form due to plasma instabilities and self-generated magnetic fields. Laboratory experiments at DOE high energy density (HED) facilities can achieve the conditions necessary for the formation of collisionless shocks and will provide a unique avenue for studying the nonlinear physics of shock waves. This project investigates the parameters and experimental configurations needed for the creation of collisionless shocks in the laboratory experiments. This study is being performed with state of the art 3D kinetic plasma simulations. Recent advances in ab-initio particle-in-cell (PIC) simulations of astrophysical shocks enable us to simulate shock formation on timescales and in geometries relevant to the laboratory experiments. The main goal of the proposal is to ascertain which signatures of shock physics can be extracted from the realistic experiments, accounting for limitations imposed by finite spatial and time scales in the lab. To aid the interpretation of current and future experimental data, PIC simulation data have been analyzed using the same diagnostic techniques as used in the laboratory, such as proton radiography and neutronics, to unambiguously predict the experimental signatures of relevant collisionless shock phenomena.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗