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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 1,675 records · Page 93
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Energy Efficient Waste Heat Coupled Forward Osmosis for Effluent Water Management at Coal-Fired Power Plants

This project sought to evaluate the technical and economic viability of the Aquapod©, a transformational low energy (<200 kJ/kg water) waste heat coupled forward osmosis (FO) technology, to manage effluents, meet cooling water demands, and achieve water conservation in a coal-fired power plant environment. The Aquapod© process is innovative because it is heat-driven, avoids the evaporation of water, and uses no toxic chemicals such as ammonia or amines. The Aquapod© process accomplishes this using an aqueous two-phase system (ATPS) coupled FO process. The evaluation revealed that the Aquapod© process offers a pathway to exploit waste heat resources within a power plant to achieve flue-gas desulfurization (FGD) wastewater volume reduction and water recovery with minimal pretreatment. Water recovery of 80% from FGD wastewater was achieved with minimal pretreatment, exceeding the project target of 50%. The estimated electrical energy of 2.16 kWh/m 3 of water produced for the Aquapod© process met the project target of < 3.6 kWh/m 3 . The heat required for the process operation was approximately 186 kJ/kg of produced water, which was slightly lower than the project target of 200 kJ/kg. The estimated treatment cost for installing and operating the Aquapod© process in conjunction with a spray dryer evaporator to achieve zero-liquid discharge (ZLD) of the 100 gpm FGD wastewater was $13.24/m 3 over a 30-year lifetime. As a point of reference, this study’s host power plant currently incurs a cost of $3.70/m 3 – $8.87/m3 on a discharged volume basis to discharge its wastewater into the publicly owned treatment works (POTW) after physical-chemical treatment. Therefore, the Illinois power plant would incur an incremental cost increase of $4.37/m 3 – 9.54/m 3 to achieve ZLD using the Aquapod© and spray dryer combination. Ample opportunities exist to further lower the ZLD capital and operating costs in the next design iteration to attain pipe parity at the higher end of the site treatment costs.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2022

Laboratory Heat Flux Estimates of Seawater Foam for Low Wind Speeds

Laboratory experiments were conducted to measure the heat flux from seafoam continuously generated in natural seawater. Using a control volume technique, heat flux was calculated from foam and foam-free surfaces as a function of ambient humidity (ranged from 40% to 78%), air–water temperature difference (ranged from -9 °C to 0 °C), and wind speed (variable up to 3 m s-1). Water-surface skin temperature was imaged with a calibrated thermal infrared camera, and near-surface temperature profiles in the air, water, and foam were recorded. Net heat flux from foam surfaces increased with increasing wind speed and was shown to be up to four times greater than a foam-free surface. The fraction of the total heat flux due to the latent heat flux was observed for foam to be 0.75, with this value being relatively constant with wind speed. In contrast, for a foam-free surface the fraction of the total heat flux due to the latent heat flux decreased at higher wind speeds. Temperature profiles through foam are linear and have larger gradients, which increased with wind speed, while foam free surfaces show the expected logarithmic profile and show no variation with temperature. The radiometric surface temperatures show that foam is cooler and more variable than a foam-free surface, and bubble-resolving thermal images show that radiometrically transparent bubble caps and burst bubbles reveal warm foam below the cool surface layer, contributing to the enhanced variability.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1973

Analytical study to define a helicopter stability derivative extraction method, volume 1

A method is developed for extracting six degree-of-freedom stability and control derivatives from helicopter flight data. Different combinations of filtering and derivative estimate are investigated and used with a Bayesian approach for derivative identification. The combination of filtering and estimate found to yield the most accurate time response match to flight test data is determined and applied to CH-53A and CH-54B flight data. The method found to be most accurate consists of (1) filtering flight test data with a digital filter, followed by an extended Kalman filter (2) identifying a derivative estimate with a least square estimator, and (3) obtaining derivatives with the Bayesian derivative extraction method.

Molusis, J. A.↗
NASA NTRS1976

Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 1: Executive summary

A data base for the comparison of advanced energy conversion systems for utility applications using coal or coal-derived fuels was developed. Estimates of power plant performance (efficiency), capital cost, cost of electricity, natural resource requirements, and environmental intrusion characteristics were made for ten advanced conversion systems. Emphasis was on the energy conversion system in the context of a base loaded utility power plant. All power plant concepts were premised on meeting emission standard requirements. A steam power plant (3500 psig, 1000 F) with a conventional coal-burning furnace-boiler was analyzed as a basis for comparison. Combined cycle gas/steam turbine system results indicated competitive efficiency and a lower cost of electricity compared to the reference steam plant. The Open-Cycle MHD system results indicated the potential for significantly higher efficiency than the reference steam plant but with a higher cost of electricity.

Corman, J. C.↗
NASA NTRS1976

A cost and utility analysis of NIM/CAMAC standards and equipment for shuttle payload data acquisition and control systems. Volume 2: Tasks 1 and 2

A representative set of payloads for both science and applications disciplines were selected that would ensure a realistic and statistically significant estimate of equipment utilization. The selected payloads were analyzed to determine the applicability of Nuclear Instrumentation Modular (NIM)/Computer Automated Measurement Control (CAMAC) equipment in satisfying their data acquisition and control requirements. The analyses results were combined with the comparable results from related studies to arrive at an overall assessment of the applicability and commonality of NIM/CAMAC equipment usage across the spectrum of payloads.

Source record↗
NASA NTRS1983

The YAV-8B simulation and modeling. Volume 2: Program listing

Detailed mathematical models of varying complexity representative of the YAV-8B aircraft are defined and documented. These models are used in parameter estimation and in linear analysis computer programs while investigating YAV-8B aircraft handling qualities. Both a six degree of freedom nonlinear model and a linearized three degree of freedom longitudinal and lateral directional model were developed. The nonlinear model is based on the mathematical model used on the MCAIR YAV-8B manned flight simulator. This simulator model has undergone periodic updating based on the results of approximately 360 YAV-8B flights and 8000 hours of wind tunnel testing. Qualified YAV-8B flight test pilots have commented that the handling qualities characteristics of the simulator are quite representative of the real aircraft. These comments are validated herein by comparing data from both static and dynamic flight test maneuvers to the same obtained using the nonlinear program.

Source record↗
NASA NTRS1983

Space station needs, attributes and architectural options study. Volume 7-2: Data book. Commercial missions

The history of NASA's materials processing in space activities is reviewed. Market projections, support requirements, orbital operations issues, cost estimates and candidate systems (orbiter sortie flight, orbiter serviced free flyer, space station, space station serviced free flyer) for the space production of semiconductor crystals are examined. Mission requirements are identified for materials processing, communications missions, bioprocessing, and for transferring aviation maintenance training technology to spacecraft.

Source record↗
DOE OSTI2018

Anomalous Lattice Properties of Manganese Monosilicide: the Thermodynamic Approach

The temperature dependences of the thermal and elastic MnSi properties are analyzed within the limits of the self-consistent approach. The role of the anharmonicity of acoustic and optical lattice vibrations is analyzed. It is demonstrated that anomalously weak anharmonicity is characteristic for acoustic phonons. In particular, this explains the temperature dependence of the MnSi bulk compressive modulus. The one-electron contribution is estimated and the anomalous non-lattice contribution to the formation of the temperature dependences of heat capacity and volume thermal expansion coefficients.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Assessing the Dosimetric Impact of Real-Time Prostate Motion During Volumetric Modulated Arc Therapy

Purpose: To develop a method for dose reconstruction by incorporating the interplay effect between aperture modulation and target motion, and to assess the dosimetric impact of real-time prostate motion during volumetric modulated arc therapy (VMAT). Methods and Materials: Clinical VMAT plans were delivered with the TrueBeam linac for 8 patients with prostate cancer. The real-time target motion during dose delivery was determined based on the 2-dimensional fiducial localization using an onboard electronic portal imaging device. The target shift in each image was correlated with the control point with the same gantry angle in the VMAT plan. An in-house-developed Monte Carlo simulation tool was used to calculate the 3-dimensional dose distribution for each control point individually, taking into account the corresponding real-time target motion (assuming a nondeformable target with no rotation). The delivered target dose was then estimated by accumulating the dose from all control points in the plan. On the basis of this information, dose–volume histograms and 3-dimensional dose distributions were calculated to assess their degradation from the planned dose caused by target motion. Thirty-two prostate motion trajectories were analyzed. Results: The minimum dose to 0.03 cm{sup 3} of the gross tumor volume (D{sub 0.03cc}) was only slightly degraded after taking motion into account, with a minimum value of 94.1% of the planned dose among all patients and fractions. However, the gross tumor volume receiving prescription dose (V{sub 100%}) could be largely affected by motion, dropping below 60% in 1 trajectory. We did not observe a correlation between motion magnitude and dose degradation. Conclusions: Prostate motion degrades the delivered dose to the target in an unpredictable way, although its effect is reduced over multiple fractions, and for most patients the degradation is small. Patients with greater prostate motion or those treated with stereotactic body radiation therapy would benefit from real-time prostate tracking to reduce the margin.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2016

Simulation Model of Microsphere Distribution for Selective Internal Radiation Therapy Agrees With Observations

Purpose: To perform a detailed analysis of microsphere distribution in biopsy material from a patient treated with {sup 90}Y-labeled resin spheres and characterize microsphere distribution in the hepatic artery tree, and to construct a novel dichotomous bifurcation model for microsphere deposits and evaluate its accuracy in simulating the observed microsphere deposits. Methods and Materials: Our virtual model consisted of arteries that successively branched into 2 new generations of arteries at 20 nodes. The artery diameter exponentially decreased from the lowest generation to the highest generation. Three variable parameters were optimized to obtain concordance between simulations and measure microsphere distributions: an artery coefficient of variation (ACV) for the diameter of all artery generations and the microsphere flow distribution at the nodes; a hepatic tree distribution volume (HDV) for the artery tree; and an artery diameter reduction (ADR) parameter. The model was tested against previously measured activity concentrations in 84 biopsies from the liver of 1 patient. In 16 of 84 biopsies, the microsphere distribution regarding cluster size and localization in the artery tree was determined via light microscopy of 30-μm sections (mean concentration, 14 microspheres/mg; distributions divided into 3 groups with mean microsphere concentrations of 4.6, 14, and 28 microspheres/mg). Results: Single spheres and small clusters were observed in terminal arterioles, whereas large clusters, up to 450 microspheres, were observed in larger arterioles. For 14 microspheres/mg, the optimized parameter values were ACV=0.35, HDV = 50 cm{sup 3}, and ADR=6 μm. For 4.6 microspheres/mg, ACV and ADR decreased to 0.26 and 0 μm, respectively, whereas HDV increased to 130 cm{sup 3}. The opposite trend was observed for 28 microspheres/mg: ACV = 0.49, HDV = 20 cm{sup 3}, and ADR = 8 μm. Conclusion: Simulations and measurements reveal that microsphere clusters are larger and more common in volumes with high microsphere concentrations and indicate that the spatial distribution of the artery tree must be considered in estimates of microsphere distributions.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2020

Arctic Sea Ice in CMIP6

Abstract We examine CMIP6 simulations of Arctic sea‐ice area and volume. We find that CMIP6 models produce a wide spread of mean Arctic sea‐ice area, capturing the observational estimate within the multimodel ensemble spread. The CMIP6 multimodel ensemble mean provides a more realistic estimate of the sensitivity of September Arctic sea‐ice area to a given amount of anthropogenic CO 2 emissions and to a given amount of global warming, compared with earlier CMIP experiments. Still, most CMIP6 models fail to simulate at the same time a plausible evolution of sea‐ice area and of global mean surface temperature. In the vast majority of the available CMIP6 simulations, the Arctic Ocean becomes practically sea‐ice free (sea‐ice area <1 × 10 6 km 2 ) in September for the first time before the Year 2050 in each of the four emission scenarios SSP1‐1.9, SSP1‐2.6, SSP2‐4.5, and SSP5‐8.5 examined here.

Notz, Dirk↗
DOE OSTI2020

Experimental and computational study of particle formation kinetics in UF6 hydrolysis

The formation and growth of UO 2 F 2 particles by gas-phase UF 6 hydrolysis remains of interest to actinide chemistry researchers. The total number concentration of the UO 2 F 2 aerosol particles that can be produced in the reaction is regulated primarily by the availability of water molecules under our reactor conditions. An increase in water molecule concentration corresponds with a higher amount and larger size of UO 2 F 2 aerosol particles produced. The growth rates of aerosol particles appear to approach a single number in the range of [0.05 ± 0.03–0.08 ± 0.04] (nm s -1 ), as the molar ratio of water to UF 6 decreases below 1. The size of primary particles produced from the UF 6 hydrolysis under water-deprived conditions was estimated to be 3.6 ± 0.4 nm. As the molar ratio became greater than 1.7, the size of primary particles increased with increased availability of water molecules. The primary particle model developed in this work predicted a size range for the UO 2 F 2 primary particles similar to that estimated based on the data from gas-phase UF 6 hydrolysis experiments. This result suggests that the volume-driven coalescence process assumption used in the derivation of the primary particle model was reasonable. The ability to precisely control the availability of water molecules and reaction time could lead to the production of nearly monodispersed aerosol particles. This finding has significant implications in the engineering and manufacturing of fuel powder materials and possibly the future development and deployment of environmental sampling apparatus.

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

Accounting for Debye sheath expansion for proud Langmuir probes in magnetic confinement fusion plasmas

A Child-Langmuir law-based method for accounting for Debye sheath expansion while fitting the current-voltage I-V characteristic of proud Langmuir probes (electrodes that extend into the volume of the plasma) is described. For Langmuir probes of a typical size used in tokamak plasmas, these new estimates of electron temperature and ion saturation current density values decreased by up to 60% compared to methods that did not account for sheath expansion. Changes to the collection area are modeled using the Child-Langmuir law and effective expansion perimeter l p , and the model is thus referred to as the “perimeter sheath expansion method.” l p is determined solely from electrode geometry, so the method may be employed without prior measurement of the magnitude of the sheath expansion effects for a given Langmuir probe and can be used for electrodes of different geometries. This method correctly predicts the non-saturating ΔI/ΔV slope for cold, low-density plasmas where sheath-expansion effects are strong, as well as for hot plasmas where ΔI/ΔV ~ 0, though it is shown that the sheath can still significantly affect the collection area in these hot conditions. The perimeter sheath expansion method has several advantages compared to methods where the non-saturating current is fitted: (1) It is more resilient to scatter in the I-V characteristics observed in turbulent plasmas. (2) It is able to separate the contributions to the ΔI/ΔV slope from sheath expansion to that of the high energy electron tail in high Te conditions. (3) It calculates the change in the collection area due to the Debye sheath for conditions where ΔI/ΔV ~ 0 and for V = V f .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Joint constraints on galaxy bias and σ{sub 8} through the N-pdf of the galaxy number density

We present a full description of the N-probability density function of the galaxy number density fluctuations. This N-pdf is given in terms, on the one hand, of the cold dark matter correlations and, on the other hand, of the galaxy bias parameter. The method relies on the assumption commonly adopted that the dark matter density fluctuations follow a local non-linear transformation of the initial energy density perturbations. The N-pdf of the galaxy number density fluctuations allows for an optimal estimation of the bias parameter (e.g., via maximum-likelihood estimation, or Bayesian inference if there exists any a priori information on the bias parameter), and of those parameters defining the dark matter correlations, in particular its amplitude (σ{sub 8}). It also provides the proper framework to perform model selection between two competitive hypotheses. The parameters estimation capabilities of the N-pdf are proved by SDSS-like simulations (both, ideal log-normal simulations and mocks obtained from Las Damas simulations), showing that our estimator is unbiased. We apply our formalism to the 7th release of the SDSS main sample (for a volume-limited subset with absolute magnitudes M{sub r} ≤ −20). We obtain b-circumflex = 1.193 ± 0.074 and σ-bar{sub 8} = 0.862 ± 0.080, for galaxy number density fluctuations in cells of the size of 30h{sup −1}Mpc. Different model selection criteria show that galaxy biasing is clearly favoured.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

An Assessment of Homogeneous Mixture Method Cavitation Models in Predicting Cavitation in Nozzle Flow

The homogeneous mixture method (HMM) is a popular class of models used in the computational prediction of cavitation. Several cavitation models have been developed for use with HMM to govern the development and destruction of vapor in a fluid system. Two models credited to Kunz and Schnerr–Sauer are studied in this paper. The goal of this work is to provide an assessment of the two cavitation submodels in their ability to predict cavitation in nozzle flow. Validation data were obtained via experiments which employ both passive cavitation detection, (PCD) via acoustic sensing and optical cavitation detection (OCD) via camera imaging. The experiments provide quantitative information on cavitation inception and qualitative information on the vapor in the nozzle. The results show that initial vapor formation is not predicted precisely but within reason. A sensitivity analysis of the models to input parameters shows that the Schnerr–Sauer method does not depend upon the estimation of nuclei size and number density. Small changes in the vapor formation rate but not the total vapor volume can be seen when weighting parameters are modified. In contrast, changes to the input parameters for the Kunz model greatly change the final total vapor volume prediction. The assessment also highlights the influence of vapor convection within the method. Finally, the analysis shows that if the fluid and nozzle walls do not support nuclei larger than 40 μm, the methods would still predict cavitation when indeed there would be none in practice.

Engineering↗
DOE OSTI2014

Spatial Analysis of Depots for Advanced Biomass Processing

The objective of this work was to perform a spatial analysis of the total feedstock cost at the conversion reactor for biomass supplied by a conventional system and an advanced system with depots to densify biomass into pellets. From these cost estimates, the conditions (feedstock cost and availability) for which advanced processing depots make it possible to achieve cost and volume targets can be identified.

09 BIOMASS FUELS↗
DOE OSTI2019

Measurement of CH{sub 3}D on Titan at Submillimeter Wavelengths

We present the first radio/submillimeter detection of monodeuterated methane (CH{sub 3}D) in Titan’s atmosphere, using archival data from of the Atacama Large Millimeter/submillimeter Array (ALMA). The J {sub K} = 2{sub 1}−1{sub 1} and J {sub K} = 2{sub 0}−1{sub 0} transitions at 465.235 and 465.250 GHz (∼0.644 mm) were measured at significance levels of 4.6σ and 5.7σ, respectively. These two lines were modeled using the Non-linear optimal Estimator for MultivariatE spectral analySIS (NEMESIS) radiative transfer code to determine the disk-averaged CH{sub 3}D volume mixing ratio = 6.157 × 10{sup −6} in Titan’s stratosphere (at altitudes >130 km). By comparison with the CH{sub 4} vertical abundance profile measured by Cassini–Huygens mass spectrometry, the resulting value for D/H in CH{sub 4} is (1.033 ± 0.081) × 10{sup −4}. This is consistent with previous ground-based and in situ measurements from the Cassini–Huygens mission, though slightly lower than the average of the previous values. Additional CH{sub 3}D observations at higher spatial resolution will be required to determine a value truly comparable with the Cassini–Huygens CH{sub 4} measurements, by measuring CH{sub 3}D with ALMA close to Titan’s equator. In the post-Cassini era, spatially resolved observations of CH{sub 3}D with ALMA will enable the latitudinal distribution of methane to be determined, making this an important molecule for further studies.

79 ASTRONOMY AND ASTROPHYSICS↗