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Lithium-CO2 batteries and beyond (open access)

Lithium-CO2 batteries and beyond

Article describes how Li-CO2 batteries with a theoretical energy density of 1,876 Wh kg−1 are attractive as a promising energy storage strategy and as an effective way to reduce greenhouse gas emissions by CO2 reduction and the formation of discharge product Li2CO3 and carbon. This article provides critical perspectives on the development of Li-CO2 batteries as well as a description of current issues and challenges associated with cathode catalysts, electrolyte, and anode for Li-CO2 batteries.
Date: March 3, 2023
Creator: Pathak, Anil; Adhikari, Pashupati R. & Choi, Wonbong
System: The UNT Digital Library
The association between posttraumatic disorder symptoms and addictive behaviours in Macao within a sample of female Filipino migrant workers: a network analysis (open access)

The association between posttraumatic disorder symptoms and addictive behaviours in Macao within a sample of female Filipino migrant workers: a network analysis

Article describes how Filipino migrant workers in Macao are vulnerable to posttraumatic stress disorder(PTSD) symptoms and addictive behaviours due to trauma histories, postmigration stressors, and access to alcohol and gambling venues. The current study investigated differential relations between PTSD symptoms and addictive behaviours in a polytrauma exposed sample of Filipino domestic workers in Macao(SAR), China.
Date: March 3, 2023
Creator: Mou, Ngai Lam; Lei, Wai Kit; Balaji, Suvasini; Contractor, Ateka A.; Latkin, Carl A. & Hall, Brian J.
System: The UNT Digital Library
A modified aeroponic system for growing small-seeded legumes and other plants to study root systems (open access)

A modified aeroponic system for growing small-seeded legumes and other plants to study root systems

Authors of the article state that various growth systems are available for studying plant root growth and plant–microbe interactions including hydroponics and aeroponics. The aim of their study is to present step-by-step instructions for fabricating an aeroponic system, also called a “caisson,” that has been in use in several legume research labs studying the development of symbiotic nitrogen fixing nodules, but for which detailed directions are not currently available.
Date: March 3, 2023
Creator: Cai, Jingya; Veerappan, Vijaykumar; Arildsen, Kate; Sullivan, Catrina; Piechowicz, Megan; Frugoli, Julia et al.
System: The UNT Digital Library
Gene-based association tests using GWAS summary statistics and incorporating eQTL (open access)

Gene-based association tests using GWAS summary statistics and incorporating eQTL

Article proposes a powerful and computationally efficient gene-based association test, called Overall. Using extended Simes procedure, Overall aggregates information from three types of traditional gene-based association tests and also incorporates expression quantitative trait locus (eQTL) information into a gene-based association test using GWAS summary statistics. The results show that this newly developed method can identify more significant genes than other methods.
Date: March 3, 2022
Creator: Cao, Xuwei; Wang, Xuexia; Zhang, Shuanglin & Sha, Qiuying
System: The UNT Digital Library
A 2.53 NEF 8-bit 10 kS/s 0.5 µm CMOS Neural Recording Read-Out Circuit with High Linearity for Neuromodulation Implants (open access)

A 2.53 NEF 8-bit 10 kS/s 0.5 µm CMOS Neural Recording Read-Out Circuit with High Linearity for Neuromodulation Implants

This article presents a power-efficient complementary metal-oxide-semiconductor (CMOS) neural signal-recording read-out circuit for multichannel neuromodulation implants.
Date: March 3, 2021
Creator: Tasneem, Nishat Tarannum & Mahbub, Ifana
System: The UNT Digital Library
Turning turtle: scaling relationships and self-righting ability in Chelydra serpentina (open access)

Turning turtle: scaling relationships and self-righting ability in Chelydra serpentina

Article investigating how shell morphology, neck length and self-righting biomechanics scale with body mass during ontogeny in Chelydra serpentina, which uses neck-powered self-righting.
Date: March 3, 2021
Creator: Ruhr, Ilan M.; Rose, Kayleigh A. R.; Sellers, William I.; Crossley, Dane A., II & Codd, Jonathan R.
System: The UNT Digital Library
Electrode and electrolyte configurations for low frequency motion energy harvesting based on reverse electrowetting (open access)

Electrode and electrolyte configurations for low frequency motion energy harvesting based on reverse electrowetting

This article explores various combinations of electrolyte concentrations, dielectrics, and dielectric thicknesses to generate maximum output power employing REWOD energy harvester with the objective of implementing a fully self-powered wearable sensor.
Date: March 3, 2021
Creator: Adhikari, Pashupati R.; Tasneem, Nishat Tarannum; Reid, Russell C. & Mahbub, Ifana
System: The UNT Digital Library
Hyperspectral Mineral Mapping in Support of Geothermal Exploration: Examples from Long Valley Caldera, CA and Dixie Valley, NV, USA (open access)

Hyperspectral Mineral Mapping in Support of Geothermal Exploration: Examples from Long Valley Caldera, CA and Dixie Valley, NV, USA

Growing interest and exploration dollars within the geothermal sector have paved the way for increasingly sophisticated suites of geophysical and geochemical tools and methodologies. The efforts to characterize and assess known geothermal fields and find new, previously unknown resources has been aided by the advent of higher spatial resolution airborne geophysics (e.g. aeromagnetics), development of new seismic processing techniques, and the genesis of modern multi-dimensional fluid flow and structural modeling algorithms, just to name a few. One of the newest techniques on the scene, is hyperspectral imaging. Really an optical analytical geochemical tool, hyperspectral imagers (or imaging spectrometers as they are also called), are generally flown at medium to high altitudes aboard mid-sized aircraft and much in the same way more familiar geophysics are flown. The hyperspectral data records a continuous spatial record of the earth's surface, as well as measuring a continuous spectral record of reflected sunlight or emitted thermal radiation. This high fidelity, uninterrupted spatial and spectral record allows for accurate material distribution mapping and quantitative identification at the pixel to sub-pixel level. In volcanic/geothermal regions, this capability translates to synoptic, high spatial resolution, large-area mineral maps generated at time scales conducive to both the faster pace of …
Date: March 3, 2004
Creator: Pickles, W. L.; Martini, B. A.; Silver, E. A. & Cocks, P. A.
System: The UNT Digital Library
Passive Seismic Monitoring for Rockfall at Yucca Mountain: Concept Tests (open access)

Passive Seismic Monitoring for Rockfall at Yucca Mountain: Concept Tests

For the purpose of proof-testing a system intended to remotely monitor rockfall inside a potential radioactive waste repository at Yucca Mountain, a system of seismic sub-arrays will be deployed and tested on the surface of the mountain. The goal is to identify and locate rockfall events remotely using automated data collecting and processing techniques. We install seismometers on the ground surface, generate seismic energy to simulate rockfall in underground space beneath the array, and interpret the surface response to discriminate and locate the event. Data will be analyzed using matched-field processing, a generalized beam forming method for localizing discrete signals. Software is being developed to facilitate the processing. To date, a three-component sub-array has been installed and successfully tested.
Date: March 3, 2003
Creator: Cheng, J.; Twilley, K.; Murvosh, H.; Tu, Y.; Luke, B.; Yfantis, A. et al.
System: The UNT Digital Library
CHANDRA AND XMM-NEWTON OBSERVATIONS OF RDCS1252.9-2927, A MASSIVE CLUSTER AT z = 1.24 (open access)

CHANDRA AND XMM-NEWTON OBSERVATIONS OF RDCS1252.9-2927, A MASSIVE CLUSTER AT z = 1.24

We present deep Chandra and XMM-Newton observations of the galaxy cluster RDCS1252.9-2927, which was selected from the ROSAT Deep Cluster Survey (RDCS) and confirmed by extensive spectroscopy with the VLT at redshift z = 1.237. With the Chandra data, the X-ray emission from the intra-cluster medium is well resolved and traced out to 500 kpc, thus allowing a measurement of the physical properties of the gas with unprecedented accuracy at this redshift. We detect a clear 6.7 keV Iron K line in the Chandra spectrum providing a redshift within 1% of the spectroscopic one. By augmenting our spectroscopic analysis with the XMM-Newton data (MOS detectors only), we significantly narrow down the 1{sigma} error bar to 10% for the temperature and 30% for the metallicity, with best fit values kT = 6.0{sup +0.7}{sub -0.5} keV, Z = 0.36{sup +0.12}{sup -0.10}Z{sub {circle_dot}}. In the likely hypothesis of hydrostatic equilibrium, we measure a total mass of M{sub 500} = (1.9{+-}0.3)10{sup 14}h{sup -1}{sub 70} M{sub {circle_dot}} within R{sub {Delta}=500} {approx} 536 kpc. Overall, these observations imply that RDCS1252.9-2927 is the most X-ray luminous and likely the most massive bona-fide cluster discovered to date at z > 1. When combined with current samples of distant …
Date: March 3, 2004
Creator: Demarco, R.; Ettori, S.; Tozzi, P.; Borgani, S.; Mainieri, V.; Nonino, M. et al.
System: The UNT Digital Library
The Evolution of Early-type Field Galaxies Selected from a NICMOS Map of the Hubble Deep Field North (open access)

The Evolution of Early-type Field Galaxies Selected from a NICMOS Map of the Hubble Deep Field North

The redshift distribution of well-defined samples of distant early-type galaxies offers a means to test the predictions of monolithic and hierarchical galaxy formation scenarios. NICMOS maps of the entire Hubble Deep Field North in the F110W and F160W filters, when combined with the available WFPC2 data, allow us to calculate photometric redshifts and determine the morphological appearance of galaxies at rest-frame optical wavelengths out to z {approx} 2.5. Here we report results for two subsamples of early-type galaxies, defined primarily by their morphologies in the F160W band, which were selected from the NICMOS data down to H{sub 160AB} < 24.0. A primary subsample is defined as the 34 galaxies with early-type galaxy morphologies and early-type galaxy spectral energy distributions. The secondary subsample is defined as those 42 objects which have early-type galaxy morphologies with non-early type galaxy spectral energy distributions. The observed redshift distributions of our two early-type samples do not match that predicted by a monolithic collapse model, which shows an overabundance at z > 1.5. A (V/V{sub max}) test confirms this result. When the effects of passive luminosity evolution are included in the calculation, the mean value of Vmax for the primary sample is 0.22 {+-} 0.05, and …
Date: March 3, 2004
Creator: Somerville, R,; Stanford, S. A.; Budavari, T. & Conselice, C. J.
System: The UNT Digital Library
Probing the precession of the inner accretion disk in Cygnus X-1 (open access)

Probing the precession of the inner accretion disk in Cygnus X-1

None
Date: March 3, 2005
Creator: Torres, D F; Romero, G E; Barcons, X & Lu, Y
System: The UNT Digital Library
MOVING SOLID METALLIC TARGETS FOR PION PRODUCTION IN THE MUON COLLIDER/NEUTRINO FACTORY PROJECT. (open access)

MOVING SOLID METALLIC TARGETS FOR PION PRODUCTION IN THE MUON COLLIDER/NEUTRINO FACTORY PROJECT.

The production of large fluxes of pions and muons using high-energy, high-intensity proton pulses impinging on solid or liquid targets presents unique problems which have not yet been entirely solved. We investigate the possibilities of using solid targets by choosing a metal of either extremely low thermal expansion coefficient 1 or exceptionally high mechanical strength. Candidates are respectively Super-Invar and Vascomax 350 or Inconel 718. Moving targets in the form of chains or cables would be required for cooling purposes. These materials seem easily capable of surviving the beam pulses required for the largest beam power contemplated. Questions regarding radiation damage effects are being investigated.
Date: March 3, 2004
Creator: THIEBERGER,P. KIRK,H. G. WEGGEL,R. J. MCDONALD,K.
System: The UNT Digital Library
Atomic X-ray Spectra of Accretion Disk Atmospheres in the Kerr Metric (open access)

Atomic X-ray Spectra of Accretion Disk Atmospheres in the Kerr Metric

We calculate the atmospheric structure of an accretion disk around a Kerr black hole and obtain its X-ray spectrum, which exhibits prominent atomic transitions under certain circumstances. The gravitational and Doppler (red)shifts of the C V, C VI, O VII, O VIII, and Fe I-XXVI emission lines are observable in active galaxies. We quantify the line emissivities as a function of radius, to identify the effects of atmospheric structure, and to determine the usefulness of these lines for probing the disk energetics. The line emissivities do not always scale linearly with the incident radiative energy, as in the case of Fe XXV and Fe XXVI. Our model incorporates photoionization and thermal balance for the plasma, the hydrostatic approximation perpendicular to the plane of the disk, and general relativistic tidal forces. We include radiative recombination rates, fluorescence yields, Compton scattering, and photoelectric opacities for the most abundant elements.
Date: March 3, 2004
Creator: Jimenez-Garate, M A; Liedahl, D A; Mauche, C W & Raymond, J C
System: The UNT Digital Library
Low-emittance monoenergetic electron and ion beams from ultra-intense laser-solid interactions (open access)

Low-emittance monoenergetic electron and ion beams from ultra-intense laser-solid interactions

Recent experiments at the LLNL Petawatt Laser have demonstrated the generation of intense, high energy beams of electrons and ions from the interaction of ultra-intense laser light with solid targets. Focused laser intensities as high as 6 x 10{sup 20} W/cm{sup 2} are achieved, at which point the quiver energies of the target electrons extend to {approx}10 MeV. In this new, fully relativistic regime of laser-plasma interactions, nuclear processes become important and nuclear techniques are required to diagnose the high-energy particle production. In recent experiments we have observed electrons accelerated to 100 MeV, up to 60 MeV brehmsstrahlung generation, photo-nuclear fission and positron-electron pair creation. We also have observed monoenergetic jets of electrons having sufficiently small emittance to be interesting as a laser-accelerated beam, if the production mechanism could be understood and controlled. The huge flux of multi-MeV ponderomotively accelerated electrons produced in the laser-solid interaction is also observed to accelerate contaminant ions from the rear surface of the solid target up to 50 MeV. We describe spectroscopic measurements which reveal intense monoenergetic beam features in the proton energy spectrum. The total spectrum contains >10{sup 13} protons, while the monoenergetic beam pulses contain {approx}1 nC of protons, and exhibits a …
Date: March 3, 2000
Creator: Cowan, T E; Roth, M; Allen, M M; Johnson, J; Hatchett, S P; Le Sage, G P et al.
System: The UNT Digital Library
PROGRESS IN DESIGNING A MUON COOLING RING WITH LITHIUM LENSES. (open access)

PROGRESS IN DESIGNING A MUON COOLING RING WITH LITHIUM LENSES.

We discuss particle tracking simulations in a storage ring with lithium lens inserts designed for the six-dimensional phase space cooling of muons by the ionization cooling. The ring design contains one or more lithium lens absorbers for transverse cooling that transmit the beam with very small beta-function values, in addition to liquid-hydrogen wedge-shaped absorbers in dispersive locations for longitudinal cooling. Such a ring could comprise the final component of a cooling system for use in a muon collider. The beam matching between dipole-quadrupole lattices and the lithium lenses is of particular interest.
Date: March 3, 2004
Creator: FUKUI,Y. CLINE,D. B. GARREN,A. A. KIRK,H. G.
System: The UNT Digital Library
Polarization measurement of Iron L-shell lines on EBIT-I (open access)

Polarization measurement of Iron L-shell lines on EBIT-I

We report measurements of the line polarization of Ne-like and F-like of iron n=3 to n=2 transitions in the x-ray region. We used the ''two-crystal technique'' developed in previous polarization measurements in our laboratory. Preliminary results from our measurements are presented together with the theoretical calculations using the Flexible Atomic Code (FAC). Our calculations show that contributions from cascades play an important role in the polarization calculations of most of the transitions. The uncertainties and difficulties of our experiments are also discussed.
Date: March 3, 2004
Creator: Chen, H.; Beiersdorfer, P.; Robbins, D.; Smith, A. J. & Gu, M. F.
System: The UNT Digital Library
Isotopic Tracing of Fuel Carbon in the Emissions of a Compression-Ignition Engine Fueled with Biodiesel Blends (open access)

Isotopic Tracing of Fuel Carbon in the Emissions of a Compression-Ignition Engine Fueled with Biodiesel Blends

Experimental tests were conducted on a Cummins 85.9 direct-injected diesel engine fueled with biodiesel blends. 20% and 50% blend levels were tested, as was 100% (neat) biodiesel. Emissions of particulate matter (PM), nitrogen oxides (NO{sub x}), hydrocarbons (HC) and CO were measured under steady-state operating conditions. The effect of biodiesel on PM emissions was mixed; however, the contribution of the volatile organic fraction to total PM was greater for the higher biodiesel blend levels. When only non-volatile PM mass was considered, reductions were observed for the biodiesel blends as well as for neat biodiesel. The biodiesel test fuels increased NO{sub x}, while HC and CO emissions were reduced. PM collected on quartz filters during the experimental runs were analyzed for carbon-14 content using accelerator mass spectrometry (AMs). These measurements revealed that carbon from the biodiesel portion of the blended fuel was marginally less likely to contribute to PM, compared to the carbon from the diesel portion of the fuel. The results are different than those obtained in previous tests with the oxygenate ethanol, which was observed to be far less likely contribute to PM than the diesel component of the blended fuel. The data suggests that chemical structure of the …
Date: March 3, 2003
Creator: Buchholz, B. A.; Cheng, A. S. & Dibble, R. W.
System: The UNT Digital Library
Measurement of the Second Order Non-linear Susceptibility of Collagen using Polarization Modulation and Phase-sensitive Detection (open access)

Measurement of the Second Order Non-linear Susceptibility of Collagen using Polarization Modulation and Phase-sensitive Detection

The measurement of the second order nonlinear susceptibility of collagen in various biological tissues has potential applications in the detection of structural changes which are related to different pathological conditions. We investigate second harmonic generation in rat-tail tendon, a highly organized collagen structure consisting of parallel fibers. Using an electro-optic modulator and a quarter-wave plate, we modulate the linear polarization of an ultra-short pulse laser beam that is used to measure second harmonic generation (SHG) in a confocal microscopy setup. Phase-sensitive detection of the generated signal, coupled with a simple model of the collagen protein structures, allows us to measure a parameter {gamma} related to nonlinear susceptibility and to determine the relative orientation of the structures. Our preliminary results indicate that it may be possible to use this parameter to characterize the structure.
Date: March 3, 2001
Creator: Stoller, P.; Kim, B. M.; Rubenchik, A. M.; Reiser, K. M. & Da Silva, L. B.
System: The UNT Digital Library
Recovery and recycling of aluminum, copper, and precious metals from dismantled weapon components (open access)

Recovery and recycling of aluminum, copper, and precious metals from dismantled weapon components

Sandia National Laboratories (SNL) is tasked to support The Department of Energy in the dismantlement and disposal of SNL designed weapon components. These components are sealed in a potting compound, and contain heavy metals, explosive, radioactive, and toxic materials. SNL developed a process to identify and remove the hazardous sub-components utilizing real-time radiography and abrasive water-jet cutting. The components were then crushed, granulated, screened, and separated into an aluminum and a precious-and-base-metals fraction using air-tables. Plastics were further cleaned for disposal as non-hazardous waste. New Mexico Bureau of Mines and Mineral Resources assisted SNL in investigation of size-reduction and separation technologies.
Date: March 3, 1994
Creator: Gundiler, I. H.; Lutz, J. D. & Wheelis, W. T.
System: The UNT Digital Library
CDF: Recent results and future prospects (open access)

CDF: Recent results and future prospects

We present recent results from the Collider Detector at Fermilab. Searches for the top quark have established a lower bound of M{sub top} > 91 GeV/c{sup 2} (at 95% confidence level). A measurement of B{sup o}{bar B}{sup o} mixing has been obtained from b{bar b} {yields} e{mu}, ee events. Measurements of b-quark production have been obtained from e + X events and J/{psi} + K events. The mass of the W boson has been determined to be M{sub W} = 79.91 {plus_minus} 0.39 GeV/c{sup 2}. In searching for new gauge bosons, we have obtained the bounds M{sub Z{prime}} > 412 GeV/c{sup 2} and M{sub W{prime}} > 520 GeV/c{sup 2} (at 95% C.L.). The lower limits on the quark and lepton compositeness scales are 1.4 TeV. In the next two years of data collection, we expect significantly more events for numerous types of physics, due to 25 times more beam luminosity, and improvement to the detector. In the longer term, the ``Main Injector`` upgrade to the accelerator, further improvements to the detector are being planned to exploit the potentials for physics. We discuss prospects for the discovery of the top quark, precise measurement of properties of b quark, and searches for …
Date: March 3, 1992
Creator: Yeh, G. P.
System: The UNT Digital Library
Effect of simultaneous and sequential detonation on explosive-induced fracture (open access)

Effect of simultaneous and sequential detonation on explosive-induced fracture

Tests were conducted in samples of polystyrene to study the effects of detonation delay on explosively induced fracturing. Two explosive charges in separate emplacement holes were fired at several choices of delay. The effect of free surfaces was minimized to make the experiments a study of blast-induced fracturing in a confined mode, i.e., deeply buried. All fractures formed on radial planes with respect to the emplacement holes. Simultaneous firing connected emplacement holes and produced fractures strongly oriented in the plane of the holes. Delayed firings in the second hole tended to suppress fracturing in the general direction of the first shot hole but to enhance fracturing away from the first hole. The effect was most dramatic in the ''medium'' delay firings; i.e., where the delay time was comparable to the dilatational wave transit time between holes. Using total surface area of cracks as a measure of damage, it was found that no choice of delay, including zero delay, could enhance the per-hole damage above that produced by an isolated shot. For medium delays, in fact, the total damage was measurably reduced.
Date: March 3, 1978
Creator: Swift, R. P.; Schatz, J. F.; Durham, W. B.; Hearst, J. R. & Kusubov, A.
System: The UNT Digital Library
Structural support system for a superconducting magnet coil (open access)

Structural support system for a superconducting magnet coil

The purpose of the ESCAR (Experimental Superconducting Accelerator Ring) project, now under way at the Lawrence Berkeley Laboratory, is to gather data and experience in the design and operation of a relatively small synchrotron employing superconducting magnets. Such data are essential to ensure that the design of future large accelerators may proceed in a knowledgeable and responsible manner. One of the many engineering problems associated with a superconducting magnet is the design of the coil suspension system. The coil, maintained at the temperature of liquid helium, must be held rigidly by a structure that does not conduct too much heat into the liquid helium system. The suspension system used on the ESCAR magnets is described. Topics covered include the coil support system requirements, ESCAR magnet support system, and operating experience.
Date: March 3, 1977
Creator: Meuser, R.B.
System: The UNT Digital Library
Diagnostics for an XUV/soft x-ray laser (open access)

Diagnostics for an XUV/soft x-ray laser

We have begun investigating the production of an XUV/soft x-ray laser, using our high-powered glass lasers as drivers. A major diagnostic for lasing is the measure of the absolute power produced in the lasing line. I have developed a spectrograph to time-resolved lasing lines in the energy range from 50 eV to greater than 200 eV. the spectrograph combines a transmission grating and x-ray streak camera to produce a flat field instrument. A cylindrical mirror is used in front of the grating to image the source and act as a collecting optic. The efficiency of the components is calibrated so that absolute intensities can be measured. I will compare the performance of this instrument with reflection grating systems. I will also discuss planned improvements to the system which should increase total throughput, image quality, and resolving power.
Date: March 3, 1984
Creator: Kauffman, R.L.; Matthews, D.L.; Ceglio, N. & Medecki, H.
System: The UNT Digital Library