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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Laboratory studies, analysis, and interpretation of the spectra of hydrocarbons present in planetary atmospheres including cyanoacetylene, acetylene, propane, and ethane

Combining broadband Fourier transform spectrometers (FTS) from the McMath facility at NSO and from NRC in Ottawa and narrow band TDL data from the laboratories with computational physics techniques has produced a broad range of results for the study of planetary atmospheres. Motivation for the effort flows from the Voyager/IRIS observations and the needs of Voyager analysis for laboratory results. In addition, anticipation of the Cassini mission adds incentive to pursue studies of observed and potentially observable constituents of planetary atmospheres. Current studies include cyanoacetylene, acetylene, propane, and ethane. Particular attention is devoted to cyanoacetylen (H3CN) which is observed in the atmosphere of Titan. The results of a high resolution infrared laboratory study of the line positions of the 663, 449, and 22.5/cm fundamental bands are presented. Line position, reproducible to better than 5 MHz for the first two bands, are available for infrared astrophysical searches. Intensity and broadening studies are in progress. Acetylene is a nearly ubiquitous atmospheric constituent of the outer planets and Titan due to the nature of methane photochemistry. Results of ambient temperature absolute intensity measurements are presented for the fundamental and two two-quantum hotband in the 730/cm region. Low temperature hotband intensity and linewidth measurements are planned.

Blass, William E.↗
NASA NTRS2017

Field Exploration and Life Detection Sampling Through Planetary Analogue Sampling (FELDSPAR).

Exploration missions to Mars rely on rovers to perform analyses over small sampling areas; however, landing sites for these missions are selected based on large-scale, low-resolution remote data. The use of Earth analogue environments to estimate the multi-scale spatial distributions of key signatures of habitability can help ensure mission science goals are met. A main goal of FELDSPAR is to conduct field operations analogous to Mars sample return in its science, operations, and technology from landing site selection, to in-field sampling location selection, remote or stand-off analysis, in situ analysis, and home laboratory analysis. Lava fields and volcanic regions are relevant analogues to Martian landscapes due to desiccation, low nutrient availability, and temperature extremes. Operationally, many Icelandic lava fields are remote enough to require that field expeditions address several sampling constraints that are experienced in robotic exploration, including in situ and sample return missions. The Fimmvruhls lava field was formed by a basaltic effusive eruption associated with the 2010 Eyjafjallajkull eruption. Mlifellssandur is a recently deglaciated plain to the north of the Myrdalsjkull glacier. Holuhraun was formed by a 2014 fissure eruptions just north of the large Vatnajkull glacier. Dyngjusandur is an alluvial plain apparently kept barren by repeated mechanical weathering. Informed by our 2013 expedition, we collected samples in nested triangular grids every decade from the 10 cm scale to the 1 km scale (as permitted by the size of the site). Satellite imagery is available for older sites, and for Mlifellssandur, Holuhraun, and Dyngjusandur we obtained overhead imagery at 1 m to 200 m elevation. PanCam-style photographs were taken in the field by sampling personnel. In-field reflectance spectroscopy was also obtained with an ASD spectrometer in Dyngjusandur. All sites chosen were 'homogeneous' in apparent color, morphology, moisture, grain size, and reflectance spectra at all scales greater than 10 cm. Field lab assays were conducted to monitor microbial habitation, including ATP quantification, qPCR for fungal, bacterial, and archaeal DNA, and direct cell imaging using fluorescence microscopy. Home laboratory analyses include Raman spectroscopy and community sequencing. ATP appeared to be significantly more sensitive to small changes in sampling location than qPCR or fluorescence microscopy. Bacterial and archaeal DNA content were more consistent at the smaller scales, but similarly variable across more distant sites. Conversely, cell counts and fungal DNA content have significant local variation but appear relatively homogeneous over scales of 1 km. ATP, bacterial DNA, and archaeal DNA content were relatively well correlated at many spatial scales. While we have observed spatial variation at various scales and are beginning to observe how that variation fluctuates over time as biodiversity recovers after an eruption, we do not yet fully understand what parameters lead to the observed spatial variation. Home laboratory analyses will help us further understand the elemental and structural composition of the basaltic matrices, but further field analyses are vital for the understanding how temperature, moisture, incident radiation, and so forth influence the habitability of a microclimate.

Field↗
DOE OSTI2021

Disassembly of Capsules after Irradiation of Prototype Metal and Nanocomposite Specimens in the High Flux Isotope Reactor

This report summarizes the disassembly, thermometry (TM) analysis, and future post-irradiation examination of irradiation capsules that contain nanodispersion-strengthened materials for the improved neutron irradiation resistance of fuel cladding and reactor core materials. All six capsules were successfully disassembled, and all TM was shipped to the Low Activation Materials Development and Analysis Laboratory for further analysis. The results of this project will support the development of new radiation-resistant materials by helping researchers understand the mechanism of defect evolution at interfaces in nanodispersion-strengthened materials.

36 MATERIALS SCIENCE↗
NASA NTRS2000

Residual Strength Analysis Methodology: Laboratory Coupons to Structural Components

The NASA Aircraft Structural Integrity (NASIP) and Airframe Airworthiness Assurance/Aging Aircraft (AAA/AA) Programs have developed a residual strength prediction methodology for aircraft fuselage structures. This methodology has been experimentally verified for structures ranging from laboratory coupons up to full-scale structural components. The methodology uses the critical crack tip opening angle (CTOA) fracture criterion to characterize the fracture behavior and a material and a geometric nonlinear finite element shell analysis code to perform the structural analyses. The present paper presents the results of a study to evaluate the fracture behavior of 2024-T3 aluminum alloys with thickness of 0.04 inches to 0.09 inches. The critical CTOA and the corresponding plane strain core height necessary to simulate through-the-thickness effects at the crack tip in an otherwise plane stress analysis, were determined from small laboratory specimens. Using these parameters, the CTOA fracture criterion was used to predict the behavior of middle crack tension specimens that were up to 40 inches wide, flat panels with riveted stiffeners and multiple-site damage cracks, 18-inch diameter pressurized cylinders, and full scale curved stiffened panels subjected to internal pressure and mechanical loads.

Dawicke, D. S.↗
DOE OSTI2016

GoAmazon 2014/15 Particle Sampling Field Campaign Report

As a part of the GoAmazon 2014/15 field deployments, samples of atmospheric particles were collected at the T3 field site (3° 12' 46.70" S, 60° 35' 53.0, Manacapuru, Brazil) established in the Amazonian region. The site was located downwind from Manaus and therefore, experienced clean conditions when winds were from northwest and polluted conditions when winds were from Manaus. During the second intensive operational period of GoAmazon 2014/15 (09/06/2014-10/02/2014), multiple samples of particles were collected using a cascade Multi-Orifice Uniform Deposition Impactor (MOUDI-110). Size-resolved samples by MOUDI (0.056-0.1, 0.1-0.18, 0.18-0.32, 0.32-0.56, 0.56-1.0, 1.0-1.8 μm) were collected for 6-12 hours. A variety of substrates, compatible with different spectro-microscopy methods of analysis, were arranged on the impactor stages. Collected aerosol samples are now stored pending laboratory analysis using multi-modal methods of chemical imaging. Our approach is to analyze only the samples of specific interest. We use the field campaign records and data on meteorology, as well as in situ measurements of gases and aerosols, to select the subset of samples for the in-depth laboratory analysis for selected episodes where changes in chemical composition of particles can be correlated with other data recorded at the site. Hence, we do not expect to perform detailed measurements on all samples—rather, only those samples with the greatest potential to provide scientific insight into aerosol chemistry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Mathematical analysis of laboratory microbial experiments demonstrating deterministic chaotic dynamics

Presented is a system of four ordinary differential equations and a mathematical analysis of microbiological experiments in a four-component chemostat—nutrient n, rods r, cocci c, and predators p. The analysis is consistent with the conclusion that previous experiments produced features of deterministic chaotic and classical dynamics depending on dilution rate. The surrogate model incorporates as much experimental detail as possible, but necessarily contains unmeasured parameters. The objective is to understand better the differences between model simulations and experimental results in complex microbial populations. The key methodology for simulation of chaotic dynamics, consistent with the measured dilution rate and microbial volume averages, was to cause the preference of p for r vs. c to vary with the r and c concentrations, to make r more competitive for nutrient than c, and to recycle some dying p biomass, leading to a modified version of the Monod kinetics model. Our mathematical model demonstrated that the occurrence of chaotic dynamics requires a predator, p, preference for r versus c to increase significantly with increases in r and c populations. Also included is a discussion of several generalizations of the existing model and a possible involvement of the minimum energy dissipation principle. This principle appears fundamental to thermodynamic systems including living systems. Several new experiments are suggested.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2012

Regulator Interface Strategies Implemented at the Y-12 National Security Complex Old Salvage Yard Soils Remediation Project, Oak Ridge, TN - 12162

The Oak Ridge Y-12 National Security Complex housed an area known as the Old Salvage Yard (OSY) that was approximately 7 acres. The OSY was used as an area for the accumulation, processing and storage of scrap metal and equipment from Y-12 operations extending from 1968 until 2009. Areas in the northern sections of OSY also have been used for the storage of used oils containing solvents and the accumulation and recycling or de-heading and crushing of 55-gal metal drums. Scrap metal operations historically involved the accumulation, sorting, storage, public sale or disposal of scrap metal and equipment. Non-containerised storage of scrap metal was routine until 1995 when scrap metal received at OSY was placed in B-24 and B-25 boxes. Under the American Recovery and Reinvestment Act (ARRA), approximately 26,759 cubic meters of scrap metal and debris were removed and disposed at both on and off-site disposal facilities including the on-site, Oak Ridge Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) landfill in 2010 and 2011. This removal action was performed in accordance with a CERCLA Record of Decision (ROD) and a close working relationship with both the U.S. Environmental Protection Agency (EPA) Region IV and Tennessee Department of Environment and Conservation (TDEC). Due to efficiencies and the excellent cooperative relationship forged with EPA Region IV and TDEC for Y-12 ARRA Cleanup Projects, a surplus of funding was available for additional remediation work that was completed in fiscal year (FY) 2011. The underlying OSY soils were targeted for characterization and potential remediation. To expedite these important activities, the U.S. Department of Energy Oak Ridge Environmental Management partnered with the regulators during detailed planning sessions through a variety of means to quickly and efficiently characterize and pinpoint areas requiring remediation according to previous ROD commitments. Data Quality Objectives (DQOs), data-sharing, real-time characterization reporting, surface and groundwater modeling and other interface planning activities were utilized to help facilitate and complete characterization and remediation activities. As a result of these strategies, the surgical extraction of one contiguous area of soil approximately 354 cubic meters is planned for FY12. The strategies discussed resulted in a major reduction of footprint remediation (i.e., 2.8% of the original estimate) which was originally estimated at over 26,759 cubic meters. The original estimate was developed using historical data collected at various times over the period of 20 years. By leveraging a hybrid sampling approach that involved both statistically-based and biased sampling locations, the area of contamination was significantly reduced resulting in both a compliant remedial design that is cost effective while mitigating a principle threat sources to surface and groundwater at the Y-12 plant. One remedial action boundary of 354 cubic meters was verified in the northern section of the Western OSY area known as the old drum de-header station for VOCs. The original estimate for disposal was in excess of 26,759 cubic meters. This area is scheduled for waste characterization and profile development in the first half of fiscal year 2012. The anticipated disposal facility is an on-site Oak Ridge CERCLA disposal landfill known as the Environmental Management Waste Management Facility (EMWMF). By utilizing the careful strategic planning, field-based screening and close cooperation of regulatory stakeholders as detailed in this paper, the total area of soil requiring remedial action within the Y-12 OSY footprint was 354 cubic meters or 2.8% of the original planned estimate. A potential waste reduction of 97.2% was realized over the original planned estimate for OSY Soils. Significant cost savings were achieved by - Minimizing the footprint of the remedial action; - Confirmatory analysis of soils instead of use of historical sampling results for waste profile development; - Targeting traditional laboratory analysis for soils that failed field screen protocols for radionuclides, heavy metals and VOCs; - Providing accurate and precise definition of RABs; and - Reduction of target contaminants for focused laboratory analysis instead of broad-range contaminants. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Idaho National Laboratory’s Analysis of ARRA-Funded Plug-in Electric Vehicle and Charging Infrastructure Projects: Final Report

Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s (DOE) Idaho National Laboratory (INL), is the lead laboratory for U.S. Department of Energy’s Advanced Vehicle Testing Activity (AVTA). INL’s conduct of the AVTA resulted in a significant base of knowledge and experience in the area of testing light-duty vehicles that reduced transportation-related petroleum consumption. Due to this experience, INL was tasked by DOE to develop agreements with companies that were the recipients of The American Recovery and Reinvestment Act of 2009 (ARRA) grants, that would allow INL to collect raw data from light-duty vehicles and charging infrastructure. INL developed non-disclosure agreements (NDAs) with several companies and their partners that resulted in INL being able to receive raw data via server-to-server connections from the partner companies. This raw data allowed INL to independently conduct data quality checks, perform analysis, and report publicly to DOE, partners, and stakeholders, how drivers used both new vehicle technologies and the deployed charging infrastructure. The ultimate goal was not the deployment of vehicles and charging infrastructure, cut rather to create real-world laboratories of vehicles, charging infrastructure and drivers that would aid in the design of future electric drive transportation systems. The five projects that INL collected data from and their partners are: • ChargePoint America - Plug-in Electric Vehicle Charging Infrastructure Demonstration • Chrysler Ram PHEV Pickup - Vehicle Demonstration • General Motors Chevrolet Volt - Vehicle Demonstration • The EV Project - Plug-in Electric Vehicle Charging Infrastructure Demonstration • EPRI / Via Motors PHEVs – Vehicle Demonstration The document serves to benchmark the performance science involved the execution, analysis and reporting for the five above projects that provided lessons learned based on driver’s use of the vehicles and recharging decisions made. Data is reported for the use of more than 25,000 vehicles and charging units.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRS2000

BOREAS TE-2 NSA Soil Lab Data

This data set contains the major soil properties of soil samples collected in 1994 at the tower flux sites in the Northern Study Area (NSA). The soil samples were collected by Hugo Veldhuis and his staff from the University of Manitoba. The mineral soil samples were largely analyzed by Barry Goetz, under the supervision of Dr. Harold Rostad at the University of Saskatchewan. The organic soil samples were largely analyzed by Peter Haluschak, under the supervision of Hugo Veldhuis at the Centre for Land and Biological Resources Research in Winnipeg, Manitoba. During the course of field investigation and mapping, selected surface and subsurface soil samples were collected for laboratory analysis. These samples were used as benchmark references for specific soil attributes in general soil characterization. Detailed soil sampling, description, and laboratory analysis were performed on selected modal soils to provide examples of common soil physical and chemical characteristics in the study area. The soil properties that were determined include soil horizon; dry soil color; pH; bulk density; total, organic, and inorganic carbon; electric conductivity; cation exchange capacity; exchangeable sodium, potassium, calcium, magnesium, and hydrogen; water content at 0.01, 0.033, and 1.5 MPascals; nitrogen; phosphorus: particle size distribution; texture; pH of the mineral soil and of the organic soil; extractable acid; and sulfur. These data are stored in ASCII text files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

Veldhuis, Hugo↗
DOE OSTI2014

Adsorptive Films in Support of In-field UF6 Destructive Assay Sample Collection and Analysis

International Atom Energy Agency (IAEA) safeguard verification measures in gaseous centrifuge enrichment plants (GCEPs) rely on environmental sampling, non-destructive assay (NDA), and destructive assay (DA) sampling and analysis to determine uranium enrichment. UF6 bias defect measurements are made by DA sampling and analysis to assure that enrichment is consistent with declarations. DA samples are collected from a limited number of cylinders for high precision, offsite mass spectrometer analysis. Samples are typically drawn from a sampling tap into a UF6 sample bottle, then packaged, sealed, and shipped under IAEA chain of custody to an offsite analytical laboratory. Future DA safeguard measures may require improvements in efficiency and effectiveness as GCEP capacities increase and UF6 shipping regulations become increasingly more restrictive. The Pacific Northwest National Laboratory (PNNL) DA sampler concept and Laser Ablation Absorption Ratio Spectrometry (LAARS) assay method are under development to potentially provide DA safeguard tools that increase inspection effectiveness and reduce sample shipping constraints. The PNNL DA sampler concept uses a handheld sampler to collect DA samples for either onsite LAARS assay or offsite laboratory analysis. The DA sampler design will use a small sampling planchet that is coated with an adsorptive film to collect controlled quantities of UF6 gas directly from a cylinder or process sampling tap. Development efforts are currently underway at PNNL to enhance LAARS assay performance to allow high-precision onsite bias defect measurements. In this paper, we report on the experimental investigation to develop adsorptive films for the PNNL DA sampler concept. These films are intended to efficiently capture UF6 and then stabilize the collected DA sample prior to onsite LAARS or offsite laboratory analysis. Several porous material composite films were investigated, including a film designed to maximize the chemical adsorption and binding of gaseous UF6 onto the sampling planchet.

destructive assay↗
DOE OSTI2022

Riverine Plastic Pollution: Sampling and Analysis Methods

Riverine plastic pollution has been found in all major U.S. rivers, but the exact amount of plastic being released to the oceans has not been quantified. Field studies conducted in U.S. rivers have used a range of sampling and analysis techniques and rarely measured the mass of the plastic collected. Measurements of riverine plastic pollution are needed to calibrate and validate models used to estimate the U.S. riverine plastic emissions to the oceans. This report surveys measurement methods used to quantify riverine pollution and current estimates of U.S. riverine plastic pollution from measurements and models. Measurement methods include field sampling and laboratory analysis. Field sampling methods are described for large (macro) and small (micro) plastic particles. Laboratory analysis methods are described for macro and microplastic with an emphasis on the detailed characterization processes of microplastics. Waterborne leachate analysis is also briefly described. Three models are described that estimate plastic pollution based on mismanaged plastic waste in the river catchment basins. The models were validated and calibrated with global data sources. The data sources were predominantly outside of the U.S., where the magnitude and composition of plastic pollution is different than what is found in U.S. rivers. Comprehensive measurements of riverine plastics are needed not only to characterize the riverine plastic pollution, but also parameterize and validate models of plastic fate and transport. This report also describes five key U.S. rivers that span a range of sizes and environmental conditions that could be sampled to obtain data to support characterization and model development of plastic pollution from rivers to oceans. Sampling and analysis protocol recommendations are made to ensure the highest quality of data are collected in the five rivers.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

On the importance of phase saturation heterogeneity in the analysis of laboratory studies of hydrate dissociation

Methane hydrates (MHs) have been considered as the future source of energy because of its vast resource volume and high energy density. Energy recovery from MH-bearing sediments has attracted intensifying research activities. Fundamentally, heat transfer, fluid flow through porous media, and the kinetics of hydrate reaction are the three key processes controlling the behavior of MH dissociation and the associated fluid production. Earlier studies have suggested that heterogeneous spatial distribution of SH is inevitable in MH-bearing samples synthesized in laboratory. In this paper, we extend our study to analyze numerically the simulation results from the two realizations of the samples (homogeneous and heterogeneous) to identify differences in the fluid production and to determine if they are sufficiently different. Additionally, we conduct a sensitivity analysis and a statistical analysis on the key transport and kinetic rate parameters that could affect hydrate dissociation and fluid production in the context of a heterogeneous hydrate-bearing sample, in an effort to provide insights that could lead to improved designs for laboratory experiments and (possibly) field applications. Our results suggest that the approximation of an artificial hydrate-bearing core with heterogeneous phase saturations by an assumption of uniform phase saturation distributions results in practically similar fluid production profile except for the very early stage with maximum 20.0% deviation in the water production. From the sensitivity and statistical analysis, we determine that gas production depends strongly on the kinetic rate constant, K d 0 and the composite thermal conductivity of the hydrate-bearing sediments, λ θ ; while, water production is very sensitive to K d 0 and the absolute permeability of the sandy medium, k. Understanding the effect of phase heterogeneity and the relative importance of key parameters on the production behavior of hydrate-bearing sediments could provide basis for novel production technologies that lead to enhanced gas production and energy efficiency in the energy recovery process.

42 ENGINEERING↗
DOE OSTI2020

Sustaining On-going Risk Communication at the Riverton, Wyoming, Processing Site - 20310

An environmental risk assessment report has been completed to provide an updated assessment regarding current site conditions for the Riverton, Wyoming, Processing site. Argonne National Laboratory conducted the assessment in collaboration with the U.S Department of Energy (DOE) Office of Legacy Management (LM) and the Northern Arapaho Natural Resources Office (NANRO). The data quality objectives process conducted confirmed that data from plants growing on the Riverton site would be useful and would address an outstanding concern. Data available from site soil, groundwater, and surface water were also used in the assessment in conjunction with the new plant data. A plant survey was then conducted in 2018 to identify the plants at the Riverton site with known traditional Native American cultural uses for sampling and analysis. Laboratory analysis was conducted on the plant samples for the contaminants of concern. Samples were collected from plants growing on the groundwater plume area of the site, and the same was done for eight other areas not affected by the groundwater plume but still within the institutional control boundary. These eight areas served as reference areas for this study. This human health and ecological assessment update provide the quantitative risk information that was qualitatively addressed in a 1995 Risk Assessment Report on plants, livestock, and surface water exposures at the Riverton site [1]. The conditions at the Riverton site are protective of human health and the environment given the results of the update, in combination with past completed remedial action and ongoing monitoring activities and IC implementation. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2010

Spheres of Earth: An Introduction to Making Observations of Earth Using an Earth System's Science Approach. Student Guide

Scientists from the Image Science and Analysis Laboratory (ISAL) at NASA's Johnson Space Center (JSC) work with astronauts onboard the International Space Station (ISS) who take images of Earth. Astronaut photographs, sometimes referred to as Crew Earth Observations, are taken using hand-held digital cameras onboard the ISS. These digital images allow scientists to study our Earth from the unique perspective of space. Astronauts have taken images of Earth since the 1960s. There is a database of over 900,000 astronaut photographs available at http://eol.jsc.nasa.gov . Images are requested by ISAL scientists at JSC and astronauts in space personally frame and acquire them from the Destiny Laboratory or other windows in the ISS. By having astronauts take images, they can specifically frame them according to a given request and need. For example, they can choose to use different lenses to vary the amount of area (field of view) an image will cover. Images can be taken at different times of the day which allows different lighting conditions to bring out or highlight certain features. The viewing angle at which an image is acquired can also be varied to show the same area from different perspectives. Pointing the camera straight down gives you a nadir shot. Pointing the camera at an angle to get a view across an area would be considered an oblique shot. Being able to change these variables makes astronaut photographs a unique and useful data set. Astronaut photographs are taken from the ISS from altitudes of 300 - 400 km (~185 to 250 miles). One of the current cameras being used, the Nikon D3X digital camera, can take images using a 50, 100, 250, 400 or 800mm lens. These different lenses allow for a wider or narrower field of view. The higher the focal length (800mm for example) the narrower the field of view (less area will be covered). Higher focal lengths also show greater detail of the area on the surface being imaged. Scientists from the Image Science and Analysis Laboratory (ISAL) at NASA s Johnson Space Center (JSC) work with astronauts onboard the International Space Station (ISS) who take images of Earth. Astronaut photographs, sometimes referred to as Crew Earth Observations, are taken using hand-held digital cameras onboard the ISS. These digital images allow scientists to study our Earth from the unique perspective of space. Astronauts have taken images of Earth since the 1960s. There is a database of over 900,000 astronaut photographs available at http://eol.jsc.nasa.gov . Images are requested by ISAL scientists at JSC and astronauts in space personally frame and acquire them from the Destiny Laboratory or other windows in the ISS. By having astronauts take images, they can specifically frame them according to a given request and need. For example, they can choose to use different lenses to vary the amount of area (field of view) an image will cover. Images can be taken at different times of the day which allows different lighting conditions to bring out or highlight certain features. The viewing angle at which an image is acquired can also be varied to show the same area from different perspectives. Pointing the camera straight down gives you a nadir shot. Pointing the camera at an angle to get a view across an area would be considered an oblique shot. Being able to change these variables makes astronaut photographs a unique and useful data set. Astronaut photographs are taken from the ISS from altitudes of 300 - 400 km (approx.185 to 250 miles). One of the current cameras being used, the Nikon D3X digital camera, can take images using a 50, 100, 250, 400 or 800mm lens. These different lenses allow for a wider or narrower field of view. The higher the focal length (800mm for example) the narrower the field of view (less area will be covered). Higher focal lengths also show greater detail of the area on the surface being imaged. There are four major systems or spheres of Earth. They are: Atmosphere, Biosphere, Hydrosphe, and Litho/Geosphere.

Graff, Paige Valderrama↗
DOE OSTI2019

Characterization of renal stone composition by using fast kilovoltage switching dual-energy computed tomography compared to laboratory stone analysis: a pilot study

Purpose: To prospectively examine the diagnostic performance of fast kilovoltage switching dual-energy computed tomography (DECT) in characterization of in vivo renal stone composition compared with postoperative stone analysis. Methods: Consecutive consenting patients scheduled for endoscopic kidney stone surgery in a tertiary referral hospital from June 2015 to January 2016 were enrolled. Patients were preoperatively scanned with single-source, fast kilovoltage switching DECT. Stone compositions were determined regarding the effective atomic number measurements. Results of the stone compositions from DECT were compared to postoperative infrared spectroscopy stone analysis as the standard reference. Results: For the 39 patients enrolled in the study, DECT was able to detect uric acid stone with sensitivity of 88.9% and specificity of 100%. There was 100% positive predictive value, 96.8% negative predictive value, and 97.4% accuracy. For non-contrast CT scan, sensitivity was 88.9%, specificity was 96.7%, positive predictive value was 88.9%, negative predictive value was 96.7%, and accuracy was 94.8%. Of the 39 samples examined, 21 (54%) were single composition, whereas 18 (46%) were combined. Single composition stones were correctly characterized by DECT in 100% (8/8) for uric acid. Whereas the result of uric acid stone containing stone discrimination in mixed composition was not so good with Z{sub eff} alone, iodine imaging can compensated this fault. Conclusions: DECT provides excellent accuracy in characterizing uric acid stone compositions. With the addition of iodine image, all of uric acid-containing stones can be determined by the DECT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2022

Critical review of the Mogi failure criterion based on true-triaxial laboratory data analysis and theoretical considerations

The influence of the intermediate principal stress, σ 2 , is disregarded when rock strength is analyzed using the Mohr-Coulomb or Hoek-Brown criteria. Several polyaxial strength criteria have been proposed to account for the influence of σ 2 . One of the methods that received considerable attention is the Mogi criterion. The criterion modifies the Nadai or Drucker-Prager approaches by exchanging the normal octahedral stress with what is introduced as the mean effective stress, σ m,2 . This change is based on experimental evidence that the influence of the intermediate principal stress on strength is less pronounced than the influence of the minimum principal stress. However, the Mogi criterion was derived somewhat empirically and consequently it is essential to analyze its potential theoretical deficiencies. In the current note, we analyzed the Mogi failure criterion, describing its characteristics in both τ oct –σ m,2 and σ 1 -σ 2 spaces. We investigated the relation between Mohr-Coulomb and Mogi criteria, which marks the basis for the commonly used Mogi-Coulomb approach. Here, we compared the performance of the Mogi criterion against available polyaxial strength data using three fitting approaches: Mogi-Coulomb based on triaxial compression results only, linear Mogi based on all polyaxial strength results, and power law Mogi also based on all data. The analysis reveals several serious deficiencies of the Mogi approach which all suggest that the Mogi criterion cannot properly represent the σ 2 dependence of rock strength in many cases.

58 GEOSCIENCES↗
DOE OSTI2015

Analysis of laboratory data on ultrasonic monitoring of permeability reduction due to biopolymer formation in unconsolidated granular media

We show how to estimate the fluid permeability changes due to accumulated biopolymer within the pore space of a granular material using laboratory measurements of overall permeability, together with various well-known quantitative measures (e.g., porosity, specific surface area, and formation factor) of the granular medium microstructure. The main focus of the paper is on mutual validation of existing theory and a synthesis of new experimental results. Here, we find that the theory and data are in good agreement within normal experimental uncertainties. We also establish quantitative empirical relationships between seismic and/or acoustic attenuation and overall permeability for these same systems.

58 GEOSCIENCES↗