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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Emissivity Tuned Emitter for RTPV Power Sources

Every mission launched by NASA to the outer planets has produced unexpected results. The Voyager I and II, Galileo, and Cassini missions produced images and collected scientific data that totally revolutionized our understanding of the solar system and the formation of the planetary systems. These missions were enabled by the use of nuclear power. Because of the distances from the Sun, electrical power was produced using the radioactive decay of a plutonium isotope. Radioisotopic Thermoelectric Generators (RTGs) used in the past and currently used Multi-Mission RTGs (MMRTGs) provide power for space missions. Unfortunately, RTGs rely on thermocouples to convert heat to electricity and are inherently inefficient ({approx} 3-7% thermal to electric efficiency). A Radioisotope Thermal Photovoltaic (RTPV) power source has the potential to reduce the specific mass of the onboard power supply by increasing the efficiency of thermal to electric conversion. In an RTPV, a radioisotope heats an emitter, which emits light to a photovoltaic (PV) cell, which converts the light into electricity. Developing an emitter tuned to the desired wavelength of the photovoltaic is a key part in increasing overall performance. Researchers at the NASA Glenn Research Center (GRC) have built a Thermal Photovoltaic (TPV) system, that utilizes a simulated General Purpose Heat Source (GPHS) from a MMRTG to heat a tantalum emitter. The GPHS is a block of graphite roughly 10 cm by 10 cm by 5 cm. A fully loaded GPHS produces 250 w of thermal power and weighs 1.6 kgs. The GRC system relies on the GPHS unit radiating at 1200 K to a tantalum emitter that, in turn, radiates light to a GaInAs photo-voltaic cell. The GRC claims system efficiency of conversion of 15%. The specific mass is around 167 kg/kWe. A RTPV power source that utilized a ceramic or ceramic-metal (cermet) matrix would allow for the combination of the heat source, canister, and emitter into one compact unit, and allow variation in size and shape to optimize temperature and emission spectra.

08 HYDROGEN↗
DOE OSTI2018

Urinary biomarkers of polycyclic aromatic hydrocarbons in pre- and peri-pubertal girls in Northern California: Predictors of exposure and temporal variability

Highlights: • PAHs, potential endocrine disruptors, were detected in the majority of young girls. • Multiple exposure sources predicted urinary PAH metabolites concentrations. • Most PAH metabolites had fair to moderate reproducibility over four years. Polycyclic aromatic hydrocarbons (PAHs), a class of chemicals produced as combustion by-products, have been associated with endocrine disruption. To understand exposure in children, who have been less studied than adults, we examined PAH metabolite concentrations by demographic characteristics, potential sources of exposure, and variability over time, in a cohort study of pre- and peri-pubertal girls in Northern California.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Lasers for Surgery and Photodynamic Therapy Final Report CRADA No. TC-0437-93

This proposed project is designed to apply the combined resources and expertise of the Lawrence Livermore National Laboratory (LLNL) and the Wellman Laboratories of Photomedicine (WL) to develop several new diode laser systems for use in photodynamic therapy (PDT) and to develop diode-pumped solid state infrared lasers for surgery. The use oflaser light-activated photosensitive dyes in the treatment and diagnosis of disease is developing rapidly. Current PDT relies on the use of large, expensive, and inefficient argon-ion laser pumped dye lasers as sources. The recent advances in the technology of diode lasers emitted in the 620-700 nm region offers an opportunity to make source technology for PDT more reliable, compact, and efficient. This project will develop visible diode lasers and control system for photodynamic therapy, and infrared diode pumped solid-state lasers for applications to surgery. Testing and evaluation of the laser systems will be performed at WL using cells, tissue in vitro, animal models, and ultimately human subjects in clinical trials. Once clinical testing is complete, commercialization will be pursued through WL ties to the medical laser industry. Several efforts within this proposed program are of interest to a number of other potential ti.NL funding sources. In particular, several of the diode pumped solid-state devices share some commonalty with work being proposed in conjunction with the Beckman Laser Institute and Medical Clinic. A further example is the commonalty with LLNL existing and proposed efforts in coupling high average power diode arrays into fiber optic delivery systems.

42 ENGINEERING↗
DOE OSTI2012

Solid State Electron Transfer via Bacterial Nanowires: Contributions Toward a Mechanistic Understanding of Geophysical Response of Biostimulated Subsurface

The degradation of organic matter by microorganisms provides a source of electrical potential or so-called 'self potential' (SP) that can be measured by using a voltmeter. During this process electrons are being produced as a waste-product and bacterial cells have to dispose of these to allow for the complete biodegradation of organic matter. Especially in anaerobic microbial communities, exo-cellular electron transfer is the most important driving force behind this process and organisms have developed different, but also similar, ways to transfer electrons to other microorganisms. Recently, it has been postulated that direct electron transfer from cell-to-cell is actually done by 'hard-wired' microorganisms. This shuttling of electrons is most likely done by certain c-type cytochromes that form the functional part of electrically conductive nanowires. In this study we investigated if nanowires can explain the geoelectrical (self potential and spectral induced polarization) signals observed at some biostimulated environments such as DOE sites. The objectives of our project are to: (1) investigate any temporal changes in the geophysical signatures (Self Potential (SP) and Induced Polarization (IP)) associated with nanowires of the bacterium Shewanella oneidensis MR-1, wild type and mtrc/omcA deletion mutant, (2) demonstrate that mutant strains of bacteria that produce nonconductive nanowires do not contribute to geoelectrical responses. We accomplished the following: (1) Provided training to students and a postdoctoral fellow that worked on the project, (2) Conducted several SP & IP measurements correlating the distribution of nanowires and SIP/SP signals in partial fulfillment of object No. 1 and 2. On the following we will report and discuss the results of our last experiment with some emphasis on the source mechanisms of both SP and IP associated with Shewanella oneidensis MR-1, wild type in sand columns.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

The Search for Spatial Extension in High-latitude Sources Detected by the Fermi Large Area Telescope

Here, we present a search for spatial extension in high-latitude ($| b| \gt 5^\circ $) sources in recent Fermi point source catalogs. The result is the Fermi High-Latitude Extended Sources Catalog, which provides source extensions (or upper limits thereof) and likelihood profiles for a suite of tested source morphologies. We find 24 extended sources, 19 of which were not previously characterized as extended. These include sources that are potentially associated with supernova remnants and star-forming regions. We also found extended γ-ray emission in the vicinity of the Cen A radio lobes and—at GeV energies for the first time—spatially coincident with the radio emission of the SNR CTA 1, as well as from the Crab Nebula. We also searched for halos around active galactic nuclei, which are predicted from electromagnetic cascades induced by the e + e – pairs that are deflected in intergalactic magnetic fields. These pairs are produced when γ-rays interact with background radiation fields. We do not find evidence for extension in individual sources or in stacked source samples. This enables us to place limits on the flux of the extended source components, which are then used to constrain the intergalactic magnetic field to be stronger than 3 × 10 –16 G for a coherence length λ ≳ 10 kpc, even when conservative assumptions on the source duty cycle are made. This improves previous limits by several orders of magnitude.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

Very wide binary stars as the primary source of stellar collisions in the galaxy

We present numerical simulations modeling the orbital evolution of very wide binaries, pairs of stars separated by over ∼10{sup 3} AU. Due to perturbations from other passing stars and the Milky Way's tide, the orbits of very wide binary stars occasionally become extremely eccentric, which forces close encounters between the companion stars. We show that this process causes a stellar collision between very wide binary companion stars once every 1000-7500 yr on average in the Milky Way. One of the main uncertainties in this collision rate is the amount of energy dissipated by dynamic tides during close (but not collisional) periastron passages. This dissipation presents a dynamical barrier to stellar collisions and can instead transform very wide binaries into close or contact binaries. However, for any plausible tidal dissipation model, very wide binary stars are an unrealized, and potentially the dominant, source of stellar collisions in our Galaxy. Such collisions should occur throughout the thin disk of the Milky Way. Stellar collisions within very wide binaries should yield a small population of single, Li-depleted, rapidly rotating massive stars.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Perovskite Electronic Ratchets for Energy Harvesting

Electronic ratchets are energy-harvesting devices that can utilize spatially asymmetric potential distributions to convert nondirectional/random sources of energy into direct current. The potential asymmetry can be generated in a number of ways, but one purported mechanism is to redistribute ions directly within the active material. Utilizing the known propensity for ion migration in lead-halide perovskites (LHP), the first LHP flashing electronic ratchet is demonstrated by using a voltage stress to intentionally redistribute halide ions within a prototypical 2D perovskite. The resulting asymmetric potential distribution across the 2D perovskite allows for conversion of both electronic noise and unbiased square-wave potentials into current. Furthermore, simultaneous application of light illumination and voltage stress enhances the asymmetric potential distribution, enabling higher current than the nonilluminated device. This work presents an electronic ratchet system that exploits facile ion migration, which can be modified by both electrical and optical stimuli, providing a model system with the potential to test outstanding mechanistic questions for electronic ratchets.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Trace Actinide Signatures of a Bulk Neptunium Sample

In nuclear forensic analyses, measurements of actinide elements in a sample can assist with identifying interdicted or unknown materials. While these radiochemical signatures have been extensively investigated in uranium materials, less is known about bulk neptunium samples. This paper describes the measurement of trace actinide concentrations and isotopic profiles in a 237 Np oxide sample. Uranium, plutonium, americium, and curium concentrations and isotopic profiles in the sample were determined and deemed potentially useful for distinguishing different sources of 237 Np. Furthermore, several different potential radiochronometry systems were also investigated; discordant results indicate that the Np sample was never completely purified of other actinide elements, or that subsequent contamination of the sample occurred. Few prior studies of neptunium materials have been reported, and these data suggest that trace actinide constituents could provide unique signatures to identify material out of regulatory control.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Status of intense permanent magnet proton source for China-accelerator driven sub-critical system Linac

Two compact intense 2.45 GHz permanent magnet proton sources and their corresponding low energy beam transport (LEBT) system were developed successfully for China accelerator driven sub-critical system in 2014. Both the proton sources operate at 35 kV potential. The beams extracted from the ion source are transported by the LEBT, which is composed of two identical solenoids, to the 2.1 MeV Radio-Frequency Quadrupole (RFQ). In order to ensure the safety of the superconducting cavities during commissioning, an electrostatic-chopper has been designed and installed in the LEBT line that can chop the continuous wave beam into a pulsed one. The minimum width of the pulse is less than 10 μs and the fall/rise time of the chopper is about 20 ns. The performance of the proton source and the LEBT, such as beam current, beam profile, emittance and the impact to RFQ injection will be presented.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRSDate not supplied

Utilizing Radiocarbon and Thermo-optical Measurements to Quantify Source Contributions for Aircraft Engine Particulate Emissions

Recent technological advancements in aircraft engine technology and fuel sources have promising potential for reducing particulate emissions from aircraft engines. During the 2022 Boeing ecoDemonstrator ground-based field campaign, particle and trace gas emissions were sampled for four different fuels, including 100% sustainable aviation fuel (SAF), petroleum-based Jet A fuel, petroleum-based Jet A low sulfur fuel, and a SAF blend. Particulate emissions were collected on quartz microfiber filters and analysed for their radiocarbon content and their elemental carbon (EC) and organic carbon (OC) concentrations. In addition, the radiocarbon content of Jet A fuel, SAF, and aircraft engine oil was also measured. We used the radiocarbon content of the particulate emissions samples and source end members to quantify the relative contribution from engine oil and fuel to carbonaceous aerosol emissions. The results from this study can be used to understand how the implementation of technological advancements in aircraft engine technology and fuel sources will likely impact future aircraft particulate emissions.

Liz Wiggins↗
NASA NTRS2012

Gigabit Ethernet Asynchronous Clock Compensation FIFO

Clock compensation for Gigabit Ethernet is necessary because the clock recovered from the 1.25 Gb/s serial data stream has the potential to be 200 ppm slower or faster than the system clock. The serial data is converted to 10-bit parallel data at a 125 MHz rate on a clock recovered from the serial data stream. This recovered data needs to be processed by a system clock that is also running at a nominal rate of 125 MHz, but not synchronous to the recovered clock. To cross clock domains, an asynchronous FIFO (first-in-first-out) is used, with the write pointer (wprt) in the recovered clock domain and the read pointer (rptr) in the system clock domain. Because the clocks are generated from separate sources, there is potential for FIFO overflow or underflow. Clock compensation in Gigabit Ethernet is possible by taking advantage of the protocol data stream features. There are two distinct data streams that occur in Gigabit Ethernet where identical data is transmitted for a period of time. The first is configuration, which happens during auto-negotiation. The second is idle, which occurs at the end of auto-negotiation and between every packet. The identical data in the FIFO can be repeated by decrementing the read pointer, thus compensating for a FIFO that is draining too fast. The identical data in the FIFO can also be skipped by incrementing the read pointer, which compensates for a FIFO draining too slowly. The unique and novel features of this FIFO are that it works in both the idle stream and the configuration streams. The increment or decrement of the read pointer is different in the idle and compensation streams to preserve disparity. Another unique feature is that the read pointer to write pointer difference range changes between compensation and idle to minimize FIFO latency during packet transmission.

Duhachek, Jeff↗
DOE OSTI2018

Peatland Acidobacteria with a dissimilatory sulfur metabolism

Sulfur-cycling microorganisms impact organic matter decomposition in wetlands and consequently greenhouse gas emissions from these globally relevant environments. However, their identities and physiological properties are largely unknown. By applying a functional metagenomics approach to an acidic peatland, we recovered draft genomes of seven novel Acidobacteria species with the potential for dissimilatory sulfite ( dsrAB , dsrC , dsrD , dsrN , dsrT , dsrMKJOP ) or sulfate respiration ( sat , aprBA , qmo ABC plus dsr genes). Surprisingly, the genomes also encoded DsrL, which so far was only found in sulfur-oxidizing microorganisms. Metatranscriptome analysis demonstrated expression of acidobacterial sulfur-metabolism genes in native peat soil and their upregulation in diverse anoxic microcosms. This indicated an active sulfate respiration pathway, which, however, might also operate in reverse for dissimilatory sulfur oxidation or disproportionation as proposed for the sulfur-oxidizing Desulfurivibrio alkaliphilus . Acidobacteria that only harbored genes for sulfite reduction additionally encoded enzymes that liberate sulfite from organosulfonates, which suggested organic sulfur compounds as complementary energy sources. Further metabolic potentials included polysaccharide hydrolysis and sugar utilization, aerobic respiration, several fermentative capabilities, and hydrogen oxidation. Our findings extend both, the known physiological and genetic properties of Acidobacteria and the known taxonomic diversity of microorganisms with a DsrAB-based sulfur metabolism, and highlight new fundamental niches for facultative anaerobic Acidobacteria in wetlands based on exploitation of inorganic and organic sulfur molecules for energy conservation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Hanford single-shell tanks leak causes and locations - 15509

Historically 67 assumed and known leaking tanks in the single-shell tank (SST) system were identified at the Hanford Site. The US DOE, Washington River Protection Solutions LLC., and the State of Washington, Department of Ecology identified 25 of the 67 tanks as likely having had liner leaks by a comprehensive review of current and historical data. The remaining tanks are those with potential leaks from sources other than liner failures such as overfilling the tanks or the failure of process lines connecting SSTs. The location of the leaks was determined, based largely on logging radiological data from dry wells installed around the tank and/or radiological data from laterals installed under select tanks. The dry wells and laterals provide the best indication of the vicinity of the leak location, but not necessarily the exact location of the leak. Twenty of the 25 liner leaks appear to have occurred at or near the bottom of the tanks. Many of the tanks appeared to have multiple leak locations. Leak locations could not be determined for all tanks with the available data. Three of the tanks showed apparent sidewall leaks. Potential causes for liner leaks that were evaluated included tank design features, tank construction conditions, waste temperature, tank waste chemistry conducive to different types of corrosion (uniform corrosion, nitrate induced stress corrosion cracking, pitting, crevice, and liquid-air interface corrosion), and bulges in the tank bottom. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Evolutionary Divergence of Marinobacter Strains in Cryopeg Brines as Revealed by Pangenomics

Marinobacter spp. are cosmopolitan in saline environments, displaying a diverse set of metabolisms that allow them to competitively occupy these environments, some of which can be extreme in both salinity and temperature. Here, we introduce a distinct cluster of Marinobacter genomes, composed of novel isolates and in silico assembled genomes obtained from subzero, hypersaline cryopeg brines, relic seawater-derived liquid habitats within permafrost sampled near Utqiaġvik, Alaska. Using these new genomes and 45 representative publicly available genomes of Marinobacter spp. from other settings, we assembled a pangenome to examine how the new extremophile members fit evolutionarily and ecologically, based on genetic potential and environmental source. This first genus-wide genomic analysis revealed that Marinobacter spp. in general encode metabolic pathways that are thermodynamically favored at low temperature, cover a broad range of organic compounds, and optimize protein usage, e.g., the Entner–Doudoroff pathway, the glyoxylate shunt, and amino acid metabolism. The new isolates contributed to a distinct clade of subzero brine-dwelling Marinobacter spp. that diverged genotypically and phylogenetically from all other Marinobacter members. The subzero brine clade displays genomic characteristics that may explain competitive adaptations to the extreme environments they inhabit, including more abundant membrane transport systems (e.g., for organic substrates, compatible solutes, and ions) and stress-induced transcriptional regulatory mechanisms (e.g., for cold and salt stress) than in the other Marinobacter clades. We also identified more abundant signatures of potential horizontal transfer of genes involved in transcription, the mobilome, and a variety of metabolite exchange systems, which led to considering the importance of this evolutionary mechanism in an extreme environment where adaptation via vertical evolution is physiologically rate limited. Assessing these new extremophile genomes in a pangenomic context has provided a unique view into the ecological and evolutionary history of the genus Marinobacter , particularly with regard to its remarkable diversity and its opportunism in extremely cold and saline environments.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2015

Radiation directivity rotation by acoustic metamaterials

We use a metamaterial-based scheme to rotate the radiation directivity of sound radiated by a source surrounded by the structure. The rotation is demonstrated through both numerical simulations and experiments. The performance persists within a broadband and is entirely independent of the location and pattern of source inside, suggesting great potential in various practical scenarios where both the signal frequency and source position may vary significantly. We have also investigated the possibility to realize versatile controls of radiation direction by tailoring the structural parameters. Our design with special directivity-steering capability may open route to loudspeaker and auditorium acoustics designs and medical ultrasound applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2016

Radiation from laser-microplasma-waveguide interactions in the ultra-intense regime

When a high-contrast ultra-relativistic (>10{sup 20} W/cm{sup 2}) laser beam enters a micro-sized plasma waveguide, the pulse energy is coupled into waveguide modes, which significantly modifies the interaction between the electrons and electromagnetic wave. Electrons pulled out from the walls of the waveguide form a dense helical bunch inside the channel and are efficiently accelerated by the transverse magnetic modes to hundreds of MeV. The asymmetry in the transverse electric and magnetic fields drives strong oscillations, which lead to the emission of bright, well-collimated, hard X-rays. In this paper, we present our study on the underlying physics in the aforementioned process using 3D particle-in-cell simulations. The mechanism of electron acceleration and the dependence of radiation properties on different laser plasma parameters are addressed. An analytic model and basic scalings for X-ray emission are also presented by considering the lowest optical modes in the waveguide, which is adequate to describe the basic phenomenon. In addition, the effects of high-order modes as well as laser polarization are also qualitatively discussed. The considered X-ray source has promising features, potentially making it a competitive candidate for a future tabletop synchrotron source.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Wireless Advanced Lighting Controls Retrofit Demonstration

Awareness of the economic costs and environmental consequences of electric energy use in buildings is steadily growing. Implementing energy efficiency measures for reducing energy consumption in buildings can be an effective strategy for managing these impacts. Within commercial buildings in the United States, electricity use for lighting accounts for 26% (around 346 TWh in 2010) and represents a large potential energy savings source. Significant lighting energy savings have already been achieved through the widespread adoption of efficient fluorescent lamps and ballasts in the past several decades. Looking towards efficient lighting operations’ innovations, wireless advanced lighting controls technology represents an increasingly viable option for capturing the next major level of lighting energy savings in new construction and building retrofits. Fundamentally, lighting is the most amenable building end use load for producing deep energy savings because of its dynamic controllability. Advanced lighting controls encompass control strategies from occupancy sensing to continuous dimming, institutional tuning and daylight harvesting. These strategies offer greater flexibility and higher granularity of control than traditional basic control methods. Historically, advanced control systems have required extensive control wiring, which has driven system costs. However, recently developed wireless lighting controls systems can be used to network lighting components, while potentially minimizing installation time and labor costs during retrofit in comparison to wired control systems.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1978

Solar power satellites: The Engineering Challenges

Certain elements of solar power satellite design and system engineering studies are reviewed analyzing solar power satellites as a potential baseload electric power source. The complete system concept concept includes not only the satellites and their ground stations, but also the space transportation for delivery of the satellites, piece by piece, into space, and the factories for their construction in space. Issues related to carrying the solar power satellite concept from the present design study phase through implementation of actual hardware are considered. The first issue category is environmental aspects of the SPS systems. The second category of issues is the technology risks associated with achieving the necessary component and subsystem performances. The third category includes the engineering issues associated with carrying out such a large scale project. The fourth issue category is financial: the funding required to bring such a project into being and the costs of the satellites and resulting cost of the power produced as compared to potential alternative energy sources.

Woodcock, G. R.↗