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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Using Landsat 8 Satellite Imagery to Analyze Biogeochemical Constituents in the Waters of the San Francisco Bay Area and Beyond

The ocean's coastal zones play a key role in our planet's health and mitigate the adverse effects of climate change. Building on the success of NASA satellite imagery in mapping land cover changes around the globe in response to climate change, deforestation, and natural disasters, I have worked to determine how aquatic reflectance images from the Landsat 8 sensor could be correlated with biogeochemical constituents within the waters of the San Francisco Bay Area and California coastline. By analyzing Landsat 8 satellite imagery from the years 2013-2020 in collaboration with data from the United States Geological Survey (USGS), San Francisco Estuary Institute (SFEI), and universities involved with the Harmful Algal Bloom Monitoring and Alert Program (HABMAP), I investigated which areas of the San Francisco Bay and California coastline demonstrated significant correlations with values extracted from the satellite imagery. Using a Chlorophyll Index (CI) ratio calculated from two Landsat 8 satellite reflectance bands, it was found that there is a positive correlation between the CI and calculated oxygen, suspended particulate matter, and silicate from several USGS sampling points. In contrast, there is a significant negative correlation between the CI and salinity, nitrite, and phosphate at those same locations. Moreover, large suspected harmful algal blooms (HABs) along the California coastline seen in the Landsat 8 imagery were corroborated with HAB data from various institutions. Understanding the effectiveness of Landsat 8 aquatic reflectance images will allow scientists to predict HABs and other nutrient cycling that may be harmful to aquatic ecosystems around the world.

Landsat↗
DOE OSTI2011

Neutron Optics Optimization for the SNS EQ-SANS Diffractometer

The extended Q-range small angle neutron scattering (EQ-SANS) diffractometer at the Spallation Neutron Source has recently been completed. Initial commissioning has shown that it has achieved its high intensity, low background, and wide dynamic range design goals. One of the key components that enable these performances is its neutron optics, which are extensively optimized using analytical and Monte Carlo methods. The EQ-SANS optics consist of a curved multichannel beam bender and sections of straight neutron guides on both ends of the bender. The bender and the guide are made of float glass coated with supermirror multilayers. The function of the optics is to ensure low instrument background by avoiding the direct line of sight of the neutron moderator at downstream locations, while transporting thermal and cold neutrons to the sample with maximum efficiency. In this work, the optimization of the EQ-SANS optics is presented.

Monte Carlo Simulations.↗
DOE OSTI2019

SANS coupled with fluid invasion approaches for characterization of overall nanopore structure and mesopore connectivity of organic-rich marine shales in China

The pore structure of shales, including pore morphology, connectivity, pore volume, specific surface area (SSA), and pore size distribution (PSD), is a significant factor in controlling gas storage and transport and the migration mechanisms of hydrocarbons. However, the lack of comprehensive characterization for both accessible and inaccessible pore structure increases the difficulty of gas-in-place estimation and gas exploration. In order to investigate the nanoscale pore system, integration of high-pressure mercury intrusion porosimetry (MIP), low-pressure N 2 /CO 2 adsorption (LNA/LCA), and small-angle neutron scattering (SANS) were employed to obtain a multi-scale quantitative characterization of the nanopore structure of organic-rich marine shale samples from the Longmaxi and Niutitang Formations in China. In this work, PSDs obtained from the combined techniques appropriately cover an overall nanopore size range of shale (0.35–15,000 nm) and overcome the limits of the individual method. Uni-, bi, and multi-modal PSDs were observed, but the sizes of a significant portion of the nanopores observed in these shales range from 0.35 to 100 nm. Pore volumes and surface areas of micropores (<2 nm), mesopores (2–50 nm), and macropores (>50 nm) were characterized based on the best performance window of each technique: LCA for micropores; LNA and SANS for mesopores; and MIP for macropores. It was found that micropores are the major contributor to the total SSA for both the Longmaxi and Niutitang shales. With respect to pore volume, however, the contribution to the total pore volume has a trend of micropore < mesopore < macropore for the Longmaxi shale samples, but micro-/mesopore volumes are greater than macropore volumes for samples of the Niutitang shale. Strong correlations were also observed between total organic carbon (TOC) content and micropore volume and surface area, which implies that organic matter is a controlling factor in the micropore system of organic-rich shales. In addition, strong correlations between methane adsorption capacity and both micro-/mesopore volumes and SSAs indicate that micro-/mesopores are governing factors for methane storage. Furthermore, the fractions of accessible mesopore volume and surface area were quantitatively estimated by SANS and LNA. Correlation analyses suggest that the accessibility of the mesopore surface area could be an indicator for gas transport and storage in mesopores in organic matter. Thus, a shale with higher connectivity could have higher gas diffusion capability but lower gas adsorption capacity, and vice versa.

58 GEOSCIENCES↗
DOE OSTI2013

Binder characterisation of mortars used at different ages in the San Lorenzo church in Milan

The paper describes a study on the mortars of the basilica of San Lorenzo in Milan, which was carried out to support an archaeological study aimed at dating and documenting the construction techniques used throughout the centuries. The church, which was founded between the 4th and 5th century, at the end of the period when Milan was the capital of the Roman Empire, was subjected in time to extensions, collapses and reconstructions that lasted until the Renaissance period and even later on. Thanks to the good state of conservation, San Lorenzo church is a collection of materials and construction techniques throughout a period of more than a millennium. Mortars were investigated in order to compare the binders used for structural elements built in different historical ages. From an archaeological study, samples of mortars attributed to the late Roman period, the Middle Ages and the Renaissance were available. The binder of each sample was separated by the aggregates and it was characterised on the basis of X-ray diffraction analysis, thermogravimetric analysis and scanning electron microscopy. Constituents of the binder were identified and their origin is discussed in order to investigate if they could be attributed to the original composition of the binder or to possible alteration in time due to atmospheric pollution. Results show that, even though the binder is mainly based on magnesian lime, there are significant differences in the microstructure of the binding matrix used in mortars ascribed to the different historical periods. In the Roman period, in correspondence of the structural elements that required higher strength, also hydraulic cocciopesto mortars were detected. Gypsum was found in most samples, which was maybe added intentionally. - Highlights: • Binders of mortars of San Lorenzo church in Milan were investigated. • Roman, Middle Ages and Renaissance samples were studied by XRD, TG and SEM. • Magnesian-lime binders containing silico-aluminates were used in all periods. • Cocciopesto hydraulic mortars were used only in the Roman period. • Gypsum was found in most samples, which was maybe added intentionally.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Mesoporous Silica Formation Mechanisms Probed Using Combined Spin–Echo Modulated Small-Angle Neutron Scattering (SEMSANS) and Small-Angle Neutron Scattering (SANS)

In this work, the initial formation stages of surfactant-templated silica thin films which grow at the air–water interface were studied using combined spin–echo modulated small-angle neutron scattering (SEMSANS) and small-angle neutron scattering (SANS). The films are formed from either a cationic surfactant or nonionic surfactant (C 16 EO 8 ) in a dilute acidic solution by the addition of tetramethoxysilane. Previous work has suggested a two stage formation mechanism with mesostructured particle formation in the bulk solution driving film formation at the solution surface. From the SEMSANS data, it is possible to pinpoint accurately the time associated with the formation of large particles in solution that go on to form the film and to show their emergence is concomitant with the appearance of Bragg peaks in the SANS pattern, associated with the two-dimensional hexagonal order. The combination of SANS and SEMSANS allows a complete depiction of the steps of the synthesis that occur in the subphase.

36 MATERIALS SCIENCE↗
DOE OSTI2016

High intensity multi beam design of SANS instrument for Dhruva reactor

A new and versatile design of Small Angle Neutron Scattering (SANS) instrument based on utilization of multi-beam is presented. The multi-pinholes and multi-slits as SANS collimator for medium flux Dhruva rearctor have been proposed and their designs have been validated using McStas simulations. Various instrument configurations to achieve different minimum wave vector transfers in scattering experiments are envisioned. These options enable smooth access to minimum wave vector transfers as low as ~ 6×10{sup −4} Å{sup −1} with a significant improvement in neutron intensity, allowing faster measurements. Such angularly well defined and intense neutron beam will allow faster SANS studies of agglomerates larger than few tens of nm.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

AmeriFlux US-LS1 San Pedro River Lewis Springs Sacaton Grassland

This is the AmeriFlux version of the carbon flux data for the site US-LS1 San Pedro River Lewis Springs Sacaton Grassland. Site Description - This is a riparian grassland located along an old alluvial terrace along the banks of the entrenched San Pedro River in southeastern Arizona. Site climate is semiarid with monsoonal (Jul-Sep) rainfall. The grasses access groundwater (depth of 2-4 m)from an alluvial aquifer recharged elsewhere. Site water balance is not closed and ET greatly exceeds precipitation. The perennial bunchgrasses use both rainfall, groundwater and occasional flood water. This groundwater-using ecosystem is far more ebulliant and productive than the upland vegetation around it (shrublands and grasslands) outside of the San Pedro River corridor.

Scott, Russell↗
DOE OSTI2020

AmeriFlux US-LS2 San Pedro River Lewis Springs Savanna

This is the AmeriFlux version of the carbon flux data for the site US-LS2 San Pedro River Lewis Springs Savanna. Site Description - A riparian savanna located on an old alluvial terrace about 0.5 km from the banks of the entrenched San Pedro River in southeastern Arizona USA. Site climate is semiarid with monsoonal (Jul-Sep) rainfall. The trees access groundwater (depth of ~7 m)from an alluvial aquifer recharged elsewhere. Therefore, site water balance is not closed and ET greatly exceeds precipitation. The perennial bunchgrasses use primarily rainfall. This groundwater-using ecosystem is far more ebulliant and productive than the upland vegetation around it (shrublands and grasslands) outside of the San Pedro River corridor.

Scott, Russell↗
DOE OSTI2023

AmeriFlux FLUXNET-1F US-xSJ NEON San Joaquin Experimental Range (SJER)

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-xSJ NEON San Joaquin Experimental Range (SJER). This is the FLUXNET version of the carbon flux data for the site US-xSJ NEON San Joaquin Experimental Range (SJER) produced by applying the standard ONEFlux (1F) software. Site Description - Located at The San Joaquin Experimental Range, in the western foothills of the Sierra Nevada, this 18.2 kilometer terrestrial field site is a mix of open woodlands, shrubs and grasslands with low density cattle grazing. SJER is an ecosystem research experimental area. It was originally conceived as a cooperative interdisciplinary research center to identify cost-effect methods of commercial livestock production in the annual grass-oak pine woodlands, while maintaining the integrity of the ecosystem. More recently, research objectives have expanded and diversified to include research projects making contributions to our knowledge of the patterns and processes working in this ecosystem.

Network), NEON (National Ecological Observatory↗
DOE OSTI2024

AmeriFlux FLUXNET-1F US-ASM USSL San Joaquin Valley Almond Medium Salinity

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-ASM USSL San Joaquin Valley Almond Medium Salinity. This is the FLUXNET version of the carbon flux data for the site US-ASM USSL San Joaquin Valley Almond Medium Salinity produced by applying the standard ONEFlux (1F) software. Site Description - almond orchard in San Joaquin Valley. Different water source and water quality than adjacent site US-SAH

Anderson, Ray G.↗
DOE OSTI2024

AmeriFlux FLUXNET-1F US-PSH USSL San Joaquin Valley Pistachio High

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-PSH USSL San Joaquin Valley Pistachio High. This is the FLUXNET version of the carbon flux data for the site US-PSH USSL San Joaquin Valley Pistachio High produced by applying the standard ONEFlux (1F) software. Site Description - High soil salinity pistachio orchard in San Joaquin Valley.

Anderson, Ray G.↗
DOE OSTI2024

AmeriFlux FLUXNET-1F US-PSL USSL San Joaquin Valley Pistachio Low

This is the AmeriFlux Management Project (AMP) created FLUXNET-1F version of the carbon flux data for the site US-PSL USSL San Joaquin Valley Pistachio Low. This is the FLUXNET version of the carbon flux data for the site US-PSL USSL San Joaquin Valley Pistachio Low produced by applying the standard ONEFlux (1F) software. Site Description - Low soil salinity pistachio orchard in San Joaquin Valley.

Anderson, Ray G.↗
DOE OSTI2025

Contrast Matching Biopolymers: A SANS-Based Approach to Structural Characterization of Chitosan

Immobilizing enzymes in polysaccharide-based matrices has been shown to improve both their stability and their catalytic efficiency. Among available materials, chitosan was selected for its abundance, biocompatibility, and versatility in a range of applications. While the broader aim of this work is to study chitosan as a matrix for immobilizing carbonic anhydrase (CA) for CO₂ capture, this study focused on determining the contrast match point (CMP) of hydrogenated and deuterated chitosan in D₂O:H₂O mixtures to enable future structural investigations using small-angle neutron scattering (SANS). Previous work successfully synthesized deuterated chitosan from Rhizopus oryzae mycelia and assessed the degree of deuteration using Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Building on this foundation, the current study determined the CMPs of both H-chitosan and D-chitosan by performing SANS measurements across a range of D₂O:H₂O solvent contrasts. The extracted CMPs for both forms correlated well with their respective calculated scattering length densities (SLDs), validating the experimental approach. These results establish a critical reference for selective contrast matching in future SANS studies of carbonic anhydrase immobilized in chitosan matrices, enabling detailed structural analysis of enzyme–matrix interactions.

Kosgallana, Chathurika J [ORNL] (ORCID:00000002851↗
DOE OSTI2011

California GAMA Special Study: Stable Isotopic Composition of Boron in Groundwater - San Diego County Domestic Well Data

The Groundwater Ambient Monitoring and Assessment (GAMA) Program is a comprehensive groundwater quality monitoring program for the state of California. Managed by the California State Water Resources Control Board (SWRCB), the goals of the Program are twofold: to improve statewide groundwater monitoring, and to increase the availability of groundwater quality information to the public. The Domestic Well Project has sampled 137 wells in San Diego County in an effort to assess the quality of these unregulated domestic use water sources. Lawrence Livermore National Laboratory (LLNL) performed isotopic analyses of domestic well water samples for the SWRCB; this study summarizes the results of measurements of the isotopic composition of dissolved boron in groundwater in 56 wells, and provides some interpretations regarding the significance of these findings. These data, in conjunction with water and nitrate isotopic composition data (Singleton et al., 2010), are useful for determining the source(s) of nitrate in potentially-contaminated San Diego County groundwater reservoirs. The isotopic composition of dissolved boron (δ 11 B) in sampled San Diego County groundwaters varies from -0.8 to +64.4 ‰. Most sampled groundwaters (44 of 56) have δ 11 B values between +20 and +50 ‰, within the isotopic composition range characteristic of animal manure. These samples tend to have high nitrate concentrations (>50 mg/L as NO 3 ) These results are consistent with isotopic composition of nitrogen in nitrate (δ 15 N) data from Singleton et al. (2010), indicating that animal manure is a primary source of nitrate in most groundwaters measured in this study. Seven samples have δ 11 B values less than +20 ‰, outside of the animal manure δ 11 B range. These groundwaters tend to have low nitrate concentrations(<10 mg/L as NO 3 ), although two have nitrate concentrations greater than 10 mg/L, suggesting that wastewater may partially contribute to their nitrate budget. No samples measured in this study have boron or nitrate isotopic compositions consistent with a mineral fertilizer nitrate source. Five sampled groundwaters have δ 11 B values greater than +50 ‰, significantly higher than any known anthropogenic boron source. More work is needed to assess the source of nitrate and boron in the greater than +50 ‰ groundwaters.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2020

Four County Permian Basin San Andres Residual Oil Zone (ROZ) Database

This document describes the spreadsheet geologic database named ROZ_SanAnd_4.xlsm used in the report ''A Four-County Appraisal of the San Andres Residual Oil Zone (ROZ) 'Fairway' of the Permian Basin''. The dataset provides geologic properties for ROZ partitions in San Andres formation in four counties in the Permian Basin. The geologic data is used to estimate total oil in place in each partition and provides the inputs needed to estimate the oil that can be produced and CO 2 stored from the application of CO 2 EOR to a partition. The database and the appraisal report are available on NETL's website under the Collection Name: Four-County San Andres ROZ Appraisal.

02 PETROLEUM↗
DOE OSTI2025

Thermal Characterization and Exhumation of Northwest San Juan Basin Area, NM

The San Juan Basin (SJB), located in southwestern Colorado northwestern New Mexico, containing Paleozoic through middle Cenozoic strata, formed as a partitioned basin approximately 80 Ma in response to the Laramide orogeny. The SJB is a commercially mature, petroleum-producing basin, and currently being explored for CCUS and geothermal resources. Modern heat flow within the SJB is spatially variable with higher geothermal gradients in its northern and eastern portions. The temporal history of the basin thermal history is essential for understanding capacity for carbon storage and geothermal exploration. We present thermochronometric analyses of two surface and two subsurface samples to constrain spatial-temporal thermal evolution of the northwestern San Juan Basin. Apatite (U-Th)/He thermochronometric analyses were conducted on Cliff House and Kirtland Formation outcrops and subsurface samples of the Ojo Alamo and Pictured Cliffs Formations from a DOE funded, CCUS project pilot-well. In addition, vitrinite reflectance data and 1D basin modelling constrain possible time-temperature pathways of the samples in an area where no previous studies have constrained the uplift/exhumation of the Hogback Monocline using thermochronometry. Modeling suggests that elevated subsurface temperatures developed simultaneously with regional late Oligiocene volcanism in the San Juan Volcanic field and timing of maximum burial in the SJB. Late Miocene to Pliocene cooling/exhumation through the apatite (U-Th)/He partial retention zone support stratigraphic evidence of the Colorado Plateau uplift, possibly regional epeirogenic uplift driven by mantle processes.

02 PETROLEUM↗
NASA NTRS1968

History of San Marco

A brief history is reported of the first San Marco project, a joint program of the United States and Italy. The Project was a three phase effort to investigate upper air density and associated ionosphere phenomena. The initial phase included the design and development of the spacecraft, the experiments, the launch complex, and a series of suborbital flights, from Wallops Island. The second phase, consisting of designing, fabricating, and testing a spacecraft for the first orbital mission, culminated in an orbital launch also from Wallops Island. The third phase consisted of further refining the experiments and spacecraft instrumentation and of establishing a full-bore scout complex in Kenya. The launch of San Marco B, in April 1967, from this complex into an equatorial orbit, concluded the initial San Marco effort.

Caporale, A. J.↗
NASA NTRS1980

Elevation changes near the San Gabriel Fault, Southern California

Analysis of repeated leveling observations in the vicinity of the San Gabriel Fault in Southern California indicate subsidence immediately south of the Fault relative to points to the north, south and east. These observations were previously interpreted as reflecting tectonic motions associated with either the 'Palmdale Bulge' or with preseismic effects of the San Fernando earthquake. Relative subsidence between 1953 and 1964 reaches approximately 9 cm and extends over a distance of more than 20 km. Subsidence occurs directly above the Saugus aquifer and shows a temporal correlation with the history of water level decline within the aquifer. The degree of subsidence of individual benchmarks is roughly proportional to the product of aquifer thickness and water level decline at the location of the benchmarks. Thses observations strongly suggest that movements of the surface near the San Gabriel Fault, previously inferred to be of tectonic origin, actually result from near surface sediment compaction within the Saugus basin.

Reilinger, R.↗