Third-generation site characterization: Cryogenic core collection, nuclear magnetic resonance, and electrical resistivity

NASA Astrophysics Data System (ADS)

Kiaalhosseini, Saeed

In modern contaminant hydrology, management of contaminated sites requires a holistic characterization of subsurface conditions. Delineation of contaminant distribution in all phases (i.e., aqueous, non-aqueous liquid, sorbed, and gas), as well as associated biogeochemical processes in a complex heterogeneous subsurface, is central to selecting effective remedies. Arguably, a factor contributing to the lack of success of managing contaminated sites effectively has been the limitations of site characterization methods that rely on monitoring wells and grab sediment samples. The overarching objective of this research is to advance a set of third-generation (3G) site characterization methods to overcome shortcomings of current site characterization techniques. 3G methods include 1) cryogenic core collection (C3) from unconsolidated geological subsurface to improve recovery of sediments and preserving key attributes, 2) high-throughput analysis (HTA) of frozen core in the laboratory to provide high-resolution, depth discrete data of subsurface conditions and processes, 3) resolution of non-aqueous phase liquid (NAPL) distribution within the porous media using a nuclear magnetic resonance (NMR) method, and 4) application of a complex resistivity method to track NAPL depletion in shallow geological formation over time. A series of controlled experiments were conducted to develop the C 3 tools and methods. The critical aspects of C3 are downhole circulation of liquid nitrogen via a cooling system, the strategic use of thermal insulation to focus cooling into the core, and the use of back pressure to optimize cooling. The C3 methods were applied at two contaminated sites: 1) F.E. Warren (FEW) Air Force Base near Cheyenne, WY and 2) a former refinery in the western U.S. The results indicated that the rate of core collection using the C3 methods is on the order of 30 foot/day. The C3 methods also improve core recovery and limits potential biases associated with flowing sands. HTA of frozen core was employed at the former refinery and FEW. Porosity and fluid saturations (i.e., aqueous, non-aqueous liquid, and gas) from the former refinery indicate that given in situ freezing, the results are not biased by drainage of pore fluids from the core during sample collection. At FEW, a comparison between the results of HTA of the frozen core collected in 2014 and the results of site characterization using unfrozen core, (second-generation (2G) methods) at the same locations (performed in 2010) indicate consistently higher contaminant concentrations using C 3. Many factors contribute to the higher quantification of contaminant concentrations using C3. The most significant factor is the preservation of the sediment attributes, in particular, pore fluids and volatile organic compounds (VOCs) in comparison to the unfrozen conventional sediment core. The NMR study was performed on laboratory-fabricated sediment core to resolve NAPL distribution within the porous media qualitatively and quantitatively. The fabricated core consisted of Colorado silica sand saturated with deionized water and trichloroethylene (TCE). The cores were scanned with a BRUKER small-animal scanner (2.3 Tesla, 100 MHz) at 20 °C and while the core was frozen at -25 °C. The acquired images indicated that freezing the water within the core suppressed the NMR signals of water-bound hydrogen. The hydrogen associated with TCE was still detectable since the TCE was in its liquid state (melting point of TCE is -73 °C). Therefore, qualitative detection of TCE within the sediment core was performed via the NMR scanning by freezing the water. A one-dimensional NMR scanning method was used for quantification of TCE mass distribution within the frozen core. However, the results indicated inconsistency in estimating the total TCE mass within the porous media. Downhole NMR logging was performed at the former refinery in the western U.S. to detect NAPL and to discriminate NAPL from water in the formation. The results indicated that detection of NMR signals to discriminate NAPL from water is compromised by the noise stemming from the active facilities and/or power lines passing over the site. A laboratory experiment was performed to evaluate the electrical response of unconsolidated porous media through time (30 days) while NAPL was being depleted. Sand columns (Colorado silica sand) contaminated with methyl tert-butyl ether (MTBE, a light non-aqueous phase liquid (LNAPL)) were studied. A multilevel electrode system was used to measure electrical resistivity of impacted sand by imposing alternative current. The trend of reduction in resistivity through the depth of columns over time followed depletion of LNAPL by volatilization. Finally, a field experiment was performed at the former refinery in the western U.S. to track natural losses of LNAPL over time. Multilevel systems consisting of water samplers, thermocouples, and electrodes were installed at a clean zone (background zone) and an LNAPL-impacted zone. In situ measurements of complex resistivity and temperature were taken and water sampling was performed for each depth (from 3 to 14 feet below the ground surface at one-foot spacing) within almost a year. At both locations, the results indicated decreases in apparent resistivity below the water table over time. This trend was supported by the geochemistry of the pore fluids. Overall, results indicate that application of the electrical resistivity method to track LNAPL depletion at field sites is difficult due to multiple conflicting factors affecting the geoelectrical response of LNAPL-impacted zones over time.

A spatially offset Raman spectroscopy method for non-destructive detection of gelatin-encapsulated powders

USDA-ARS?s Scientific Manuscript database

Non-destructive subsurface detection of encapsulated, coated, or seal-packaged foods and pharmaceuticals can help prevent distribution and consumption of counterfeit or hazardous products. This study used a Spatially Offset Raman Spectroscopy (SORS) method to detect and identify urea, ibuprofen, and...

ANALYSIS OF VOLATILES AND SEMIVOLATILES BY DIRECT AQUEOUS INJECTION

EPA Science Inventory

Direct aqueous injection analysis (DAI) with gas chromatographic separation and ion trap mass spectral detection was used to analyze aqueous samples for g/L levels of 54 volatile and semivolatile compounds, and problematic non-purgeables and non-extractables. The method reduces ...

Test plan for Geo-Cleanse{reg_sign} demonstration (in situ destruction of dense non-aqueous phase liquid (DNAPL))

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jerome, K.M.; Looney, B.B.; Accorsi, F.

1996-09-01

Soils and groundwater beneath an abandoned process sewer line in the A/M Area of the Savannah River Site (SRS) contain elevated levels of volatile organic compounds, specifically trichloroethylene (TCE) and tetrachloroethylene (PCE), two common chlorinated solvents. These compounds have low aqueous solubilities, thus when released to the subsurface in sufficient quantity, tend to exist as immiscible fluids or nonaqueous phase liquids (NAPLs). Because chlorinated solvents are also denser than water, they are referred to by the acronym DNAPLs, or dense non-aqueous phase liquids. Technologies targeted at the efficient characterization or removal of DNAPL are not currently proven. For example, mostmore » DNAPL studies rely on traditional soil and water sampling and the fortuitous observation of immiscible solvent. Once DNAPL is identified, soil excavation (which is only applicable to small contained spill sites) is the only proven cleanup method. New cleanup approaches based on destruction of DNAPL either in situ or ex situ have been proposed and tested at the pilot scale. The proposed demonstration, as described in this report will evaluate the applicability to DNAPL plumes of a technology proven for in situ destruction of light non-aqueous phase liquids (LNAPLs) such as oils.« less

A Mobile Acoustic Subsurface Sensing (MASS) System for Rapid Roadway Assessment

PubMed Central

Lu, Yifeng; Zhang, Yi; Cao, Yinghong; McDaniel, J. Gregory; Wang, Ming L.

2013-01-01

Surface waves are commonly used for vibration-based nondestructive testing for infrastructure. Spectral Analysis of Surface Waves (SASW) has been used to detect subsurface properties for geologic inspections. Recently, efforts were made to scale down these subsurface detection approaches to see how they perform on small-scale structures such as concrete slabs and pavements. Additional efforts have been made to replace the traditional surface-mounted transducers with non-contact acoustic transducers. Though some success has been achieved, most of these new approaches are inefficient because they require point-to-point measurements or off-line signal analysis. This article introduces a Mobile Acoustic Subsurface Sensing system as MASS, which is an improved surface wave based implementation for measuring the subsurface profile of roadways. The compact MASS system is a 3-wheeled cart outfitted with an electromagnetic impact source, distance register, non-contact acoustic sensors and data acquisition/processing equipment. The key advantage of the MASS system is the capability to collect measurements continuously at walking speed in an automatic way. The fast scan and real-time analysis advantages are based upon the non-contact acoustic sensing and fast air-coupled surface wave analysis program. This integration of hardware and software makes the MASS system an efficient mobile prototype for the field test. PMID:23698266

Optical method and apparatus for detection of surface and near-subsurface defects in dense ceramics

DOEpatents

Ellingson, William A.; Brada, Mark P.

1995-01-01

A laser is used in a non-destructive manner to detect surface and near-subsurface defects in dense ceramics and particularly in ceramic bodies with complex shapes such as ceramic bearings, turbine blades, races, and the like. The laser's wavelength is selected based upon the composition of the ceramic sample and the laser can be directed on the sample while the sample is static or in dynamic rotate or translate motion. Light is scattered off surface and subsurface defects using a preselected polarization. The change in polarization angle is used to select the depth and characteristics of surface/subsurface defects. The scattered light is detected by an optical train consisting of a charge coupled device (CCD), or vidicon, television camera which, in turn, is coupled to a video monitor and a computer for digitizing the image. An analyzing polarizer in the optical train allows scattered light at a given polarization angle to be observed for enhancing sensitivity to either surface or near-subsurface defects. Application of digital image processing allows subtraction of digitized images in near real-time providing enhanced sensitivity to subsurface defects. Storing known "feature masks" of identified defects in the computer and comparing the detected scatter pattern (Fourier images) with the stored feature masks allows for automatic classification of detected defects.

Non-aqueous phase cold vapor generation and determination of trace cadmium by atomic fluorescence spectrometry.

PubMed

Lei, Zirong; Chen, Luqiong; Hu, Kan; Yang, Shengchun; Wen, Xiaodong

2018-06-05

Cold vapor generation (CVG) of cadmium was firstly accomplished in non-aqueous media by using solid reductant of potassium borohydride (KBH 4 ) as a derivation reagent. The mixture of surfactant Triton X-114 micelle and octanol was innovatively used as the non-aqueous media for the CVG and atomic fluorescence spectrometry (AFS) was used for the elemental determination. The analyte ions were firstly extracted into the non-aqueous media from the bulk aqueous phase of analyte/sample solution via a novelly established ultrasound-assisted rapidly synergistic cloud point extraction (UARS-CPE) process and then directly mixed with the solid redcutant KBH 4 to generate volatile elemental state cadmium in a specially designed reactor, which was then rapidly transported to a commercial atomic fluorescence spectrometer for detection. Under the optimal conditions, the limit of detection (LOD) for cadmium was 0.004 μg L -1 . Compared to conventional hydride generation (HG)-AFS, the efficiency of non-aqueous phase CVG and the analytical performance of the developed system was considerably improved. Copyright © 2018 Elsevier B.V. All rights reserved.

Subcritical fracturing of shales under chemically reactive conditions

NASA Astrophysics Data System (ADS)

Chen, X.; Callahan, O. A.; Eichhubl, P.; Olson, J. E.

2016-12-01

Growth of opening-mode fractures under chemically reactive subsurface conditions is potentially relevant for seal integrity in subsurface CO2 storage and hazardous waste disposal. Using double-torsion load relaxation tests we determine mode-I fracture toughness (KIC), subcritical index (SCI), and the stress-intensity factor vs fracture velocity (K-V) behavior of Marcellus, Woodford, and Mancos shales. Samples are tested under ambient air and aqueous conditions with variable NaCl and KCl concentrations, variable pH, and temperatures of up to 70. Under ambient air condition, KIC determined from double torsion tests is 1.3, 0.6, and 1.1 MPam1/2 for Marcellus, Woodford, and Mancos shales, respectively. SCI under ambient air condition is between 55 and 90 for the shales tested. Tests in aqueous solutions show a significant drop of KIC compared to ambient air condition. For tests in deionized water, KIC reduction is 18.5% for Marcellus and 47.0% for Woodford. The presence of aqueous fluids also results in a reduction of the SCI up to 85% compared to ambient condition. K-V curves generally obey a power-law relation throughout the load-relaxation period. However, aqueous-based tests on samples result in K-V curves deviating from the power-law relation, with the SCI values gradually decreasing with time during the relaxation period. This non-power-law behavior is obvious in Woodford and Mancos, but negligible in Marcellus. We find that the shales interact with the aqueous solution both at the fracture tip and within the rock matrix during subcritical fracturing. For Marcellus shale, water mainly interacts with the fracture tip on both tests due to low matrix permeability and less reactive mineral composition. However, Woodford and Mancos react strongly with water causing significant sample degradation. The competition between degradation and fracture growth results in the time-dependent SCI: at lower fracture velocities, the tip interacts longer with the chemically altered area around the tip; at higher fracture velocities, the fracture propagates through the altered area before significant degradation. Our results display strong weakening effects of chemically reactive fluids on subcritical fracture properties with implications on subsurface storage seal performance.

Sherwood correlation for dissolution of pooled NAPL in porous media

NASA Astrophysics Data System (ADS)

Aydin Sarikurt, Derya; Gokdemir, Cagri; Copty, Nadim K.

2017-11-01

The rate of interphase mass transfer from non-aqueous phase liquids (NAPLs) entrapped in the subsurface into the surrounding mobile aqueous phase is commonly expressed in terms of Sherwood (Sh) correlations that are expressed as a function of flow and porous media properties. Because of the lack of precise methods for the estimation of the interfacial area separating the NAPL and aqueous phases, most studies have opted to use modified Sherwood expressions that lump the interfacial area into the interphase mass transfer coefficient. To date, there are only two studies in the literature that have developed non-lumped Sherwood correlations; however, these correlations have undergone limited validation. In this paper controlled dissolution experiments from pooled NAPL were conducted. The immobile NAPL mass is placed at the bottom of a flow cell filled with porous media with water flowing horizontally on top. Effluent aqueous phase concentrations were measured for a wide range of aqueous phase velocities and for two different porous media. To interpret the experimental results, a two-dimensional pore network model of the NAPL dissolution kinetics and aqueous phase transport was developed. The observed effluent concentrations were then used to compute best-fit mass transfer coefficients. Comparison of the effluent concentrations computed with the two-dimensional pore network model to those estimated with one-dimensional analytical solutions indicates that the analytical model which ignores the transport in the lateral direction can lead to under-estimation of the mass transfer coefficient. Based on system parameters and the estimated mass transfer coefficients, non-lumped Sherwood correlations were developed and compared to previously published data. The developed correlations, which are a significant improvement over currently available correlations that are associated with large uncertainties, can be incorporated into future modeling studies requiring non-lumped Sh expressions.

Raman spectroscopy method for subsurface detection of food powders through plastic layers

NASA Astrophysics Data System (ADS)

Dhakal, Sagar; Chao, Kuanglin; Qin, Jianwei; Schmidt, Walter F.; Kim, Moon S.; Chan, Diane E.; Bae, Abigail

2017-05-01

Proper chemical analyses of materials in sealed containers are important for quality control purpose. Although it is feasible to detect chemicals at top surface layer, it is relatively challenging to detect objects beneath obscuring surface. This study used spatially offset Raman spectroscopy (SORS) method to detect urea, ibuprofen and acetaminophen powders contained within one or more (up to eight) layers of gelatin capsules to demonstrate subsurface chemical detection and identification. A 785 nm point-scan Raman spectroscopy system was used to acquire spatially offset Raman spectra for an offset range of 0 to 10 mm from the surfaces of 24 encapsulated samples, using a step size of 0.1 mm to obtain 101 spectral measurements per sample. With increasing offset distance, the fraction of information from the deeper subsurface material increased compared to that from the top surface material. The series of measurements was analyzed to differentiate and identify the top surface and subsurface materials. Containing mixed contributions from the powder and capsule, the SORS of each sample was decomposed using self modeling mixture analysis (SMA) to obtain pure component spectra of each component and corresponding components were identified using spectral information divergence values. Results show that SORS technique together with SMA method has a potential for non-invasive detection of chemicals at deep subsurface layer.

Optical method and apparatus for detection of surface and near-subsurface defects in dense ceramics

DOEpatents

Ellingson, W.A.; Brada, M.P.

1995-06-20

A laser is used in a non-destructive manner to detect surface and near-subsurface defects in dense ceramics and particularly in ceramic bodies with complex shapes such as ceramic bearings, turbine blades, races, and the like. The laser`s wavelength is selected based upon the composition of the ceramic sample and the laser can be directed on the sample while the sample is static or in dynamic rotate or translate motion. Light is scattered off surface and subsurface defects using a preselected polarization. The change in polarization angle is used to select the depth and characteristics of surface/subsurface defects. The scattered light is detected by an optical train consisting of a charge coupled device (CCD), or vidicon, television camera which, in turn, is coupled to a video monitor and a computer for digitizing the image. An analyzing polarizer in the optical train allows scattered light at a given polarization angle to be observed for enhancing sensitivity to either surface or near-subsurface defects. Application of digital image processing allows subtraction of digitized images in near real-time providing enhanced sensitivity to subsurface defects. Storing known ``feature masks`` of identified defects in the computer and comparing the detected scatter pattern (Fourier images) with the stored feature masks allows for automatic classification of detected defects. 29 figs.

Visible-Near Infrared Point Spectrometry of Drill Core Samples from Río Tinto, Spain: Results from the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) Drilling Exercise

NASA Astrophysics Data System (ADS)

Sutter, Brad; Brown, Adrian J.; Stoker, Carol R.

2008-10-01

Sampling of subsurface rock may be required to detect evidence of past biological activity on Mars. The Mars Astrobiology Research and Technology Experiment (MARTE) utilized the Río Tinto region, Spain, as a Mars analog site to test dry drilling technologies specific to Mars that retrieve subsurface rock for biological analysis. This work examines the usefulness of visible-near infrared (VNIR) (450-1000 nm) point spectrometry to characterize ferric iron minerals in core material retrieved during a simulated Mars drilling mission. VNIR spectrometry can indicate the presence of aqueously precipitated ferric iron minerals and, thus, determine whether biological analysis of retrieved rock is warranted. Core spectra obtained during the mission with T1 (893-897 nm) and T2 (644-652 nm) features indicate goethite-dominated samples, while relatively lower wavelength T1 (832-880 nm) features indicate hematite. Hematite/goethite molar ratios varied from 0 to 1.4, and within the 880-898 nm range, T1 features were used to estimate hematite/goethite molar ratios. Post-mission X-ray analysis detected phyllosilicates, which indicates that examining beyond the VNIR (e.g., shortwave infrared, 1000-2500 nm) will enhance the detection of other minerals formed by aqueous processes. Despite the limited spectral range of VNIR point spectrometry utilized in the MARTE Mars drilling simulation project, ferric iron minerals could be identified in retrieved core material, and their distribution served to direct core subsampling for biological analysis.

Visible-near infrared point spectrometry of drill core samples from Río Tinto, Spain: results from the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) drilling exercise.

PubMed

Sutter, Brad; Brown, Adrian J; Stoker, Carol R

2008-10-01

Sampling of subsurface rock may be required to detect evidence of past biological activity on Mars. The Mars Astrobiology Research and Technology Experiment (MARTE) utilized the Río Tinto region, Spain, as a Mars analog site to test dry drilling technologies specific to Mars that retrieve subsurface rock for biological analysis. This work examines the usefulness of visible-near infrared (VNIR) (450-1000 nm) point spectrometry to characterize ferric iron minerals in core material retrieved during a simulated Mars drilling mission. VNIR spectrometry can indicate the presence of aqueously precipitated ferric iron minerals and, thus, determine whether biological analysis of retrieved rock is warranted. Core spectra obtained during the mission with T1 (893-897 nm) and T2 (644-652 nm) features indicate goethite-dominated samples, while relatively lower wavelength T1 (832-880 nm) features indicate hematite. Hematite/goethite molar ratios varied from 0 to 1.4, and within the 880-898 nm range, T1 features were used to estimate hematite/goethite molar ratios. Post-mission X-ray analysis detected phyllosilicates, which indicates that examining beyond the VNIR (e.g., shortwave infrared, 1000-2500 nm) will enhance the detection of other minerals formed by aqueous processes. Despite the limited spectral range of VNIR point spectrometry utilized in the MARTE Mars drilling simulation project, ferric iron minerals could be identified in retrieved core material, and their distribution served to direct core subsampling for biological analysis.

A survey of the geophysical properties of chlorinated DNAPLs

NASA Astrophysics Data System (ADS)

Ajo-Franklin, Jonathan B.; Geller, Jil T.; Harris, Jerry M.

2006-07-01

Dense Non Aqueous Phase Liquids (DNAPLs) are a family of fluids often encountered as industrial contaminants. Some of the most problematic DNAPLs are chlorinated solvents such as trichloroethylene (TCE) and tetrachloroethylene (PCE). While many DNAPLs have been extensively studied from a hydrology perspective, documentation of DNAPL properties relevant to geophysical detection is far from complete. We present a short survey of acoustic velocity, density, and dielectric constant measurements for an important subset of commonly encountered dense chlorinated contaminants. Viscosity and surface tension data are included to allow exploration of contaminant signatures within the context of poroelastic or contact theory models. Where available, the temperature dependence of solvent properties are also provided. Densities for the listed DNAPLs range from 1253 to 1622 kg/m 3 at 20 °C. All are effectively non-polar with dielectric constants between 2.2 and 10.9 and have relatively low compressional wave velocities ranging from 938 to 1217 m/s. We conclude with documentation of a small collection of recent experiments investigating the properties of soils partially saturated with similar fluids. Current laboratory evidence demonstrates that DNAPLs can produce changes in geophysically measurable properties. We hope that this survey will facilitate further studies of the feasibility and effectiveness of geophysical techniques for detection of DNAPLs in the subsurface.

SOLID OXYGEN SOURCE FOR BIOREMEDIATION IN SUBSURFACE SOILS

EPA Science Inventory

Sodium percarbonate was encapsulated in poly(vinylidene chloride) to determine its potential as a slow-release oxygen source for biodegradation of contaminan ts in subsurface soils. In laboratory studies under aqueous conditions, the encapsulated sodium percarbonate was estimate...

Discriminative Random Field Models for Subsurface Contamination Uncertainty Quantification

NASA Astrophysics Data System (ADS)

Arshadi, M.; Abriola, L. M.; Miller, E. L.; De Paolis Kaluza, C.

2017-12-01

Application of flow and transport simulators for prediction of the release, entrapment, and persistence of dense non-aqueous phase liquids (DNAPLs) and associated contaminant plumes is a computationally intensive process that requires specification of a large number of material properties and hydrologic/chemical parameters. Given its computational burden, this direct simulation approach is particularly ill-suited for quantifying both the expected performance and uncertainty associated with candidate remediation strategies under real field conditions. Prediction uncertainties primarily arise from limited information about contaminant mass distributions, as well as the spatial distribution of subsurface hydrologic properties. Application of direct simulation to quantify uncertainty would, thus, typically require simulating multiphase flow and transport for a large number of permeability and release scenarios to collect statistics associated with remedial effectiveness, a computationally prohibitive process. The primary objective of this work is to develop and demonstrate a methodology that employs measured field data to produce equi-probable stochastic representations of a subsurface source zone that capture the spatial distribution and uncertainty associated with key features that control remediation performance (i.e., permeability and contamination mass). Here we employ probabilistic models known as discriminative random fields (DRFs) to synthesize stochastic realizations of initial mass distributions consistent with known, and typically limited, site characterization data. Using a limited number of full scale simulations as training data, a statistical model is developed for predicting the distribution of contaminant mass (e.g., DNAPL saturation and aqueous concentration) across a heterogeneous domain. Monte-Carlo sampling methods are then employed, in conjunction with the trained statistical model, to generate realizations conditioned on measured borehole data. Performance of the statistical model is illustrated through comparisons of generated realizations with the `true' numerical simulations. Finally, we demonstrate how these realizations can be used to determine statistically optimal locations for further interrogation of the subsurface.

High Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Framgos, William

1999-06-01

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data can bemore » mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach. Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2002-11-20

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001; Song et al., 2002). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring, and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex

2000-06-01

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data can bemore » mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach (Song et al., 1997). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2001-06-10

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001). Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

SORPTION OF VOLATILE ORGANIC SOLVENTS FROM AQUEOUS SOLUTION ONTO SUBSURFACE SOLIDS

EPA Science Inventory

Sorption isotherms for tetrachloroethene on low-carbon subsurface core samples were linear to equilibrium solution concentrations of 2 mg L−1. Concentrations above this value produced pronounced curvature in the sorption isotherms. Sorption of tetrachloroethene, benzene, trichlor...

Rheological Properties of Aqueous Colloidal Silica Suspensions Related to Amendment Delivery for Subsurface Remediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Shuo; Zhong, Lirong; Li, Guanghe

Colloidal silica (fumed silica) suspensions are being tested as carriers for remedial amendment delivery in subsurface remediation and as media for underground contamination containment. The knowledge of the rheological behavior of the silica suspensions is lack in the literature while it is essential for the preparation and field injection of the suspensions. This contribution is focused on the rheological characteristics of colloidal silica suspensions under various environmental conditions relevant to amendment delivery for subsurface remediation. We investigated the influence of silica particle concentration, water source, ionic strength, pH, aging, amendment type and concentration, and subsurface sediment on the rheological behaviormore » of the suspensions. All tested suspension formulations exhibited shear thinning before gelation. Higher silica particle concentration and salinity (Na+ and K+) increased suspensions’ viscosity and the degree of shear thinning. The viscosity of suspensions increased with aging. The suspensions at natural pH exhibited the highest viscosity compared to the acidic and alkaline suspensions with the same silica concentration. Addition of KMnO4 amendment to aqueous silica suspensions increased viscosity, while addition of alcohol amendment decreased suspensions’ viscosity. The presence of amendment did not reduce shear thinning. The gelation rate of silica suspensions was increased with silica concentration and with the addition of sediments. The rheological characteristics of shear thinning aqueous fumed silica suspensions were compared to that of shear thinning solutions formed with organic polymer xanthan gum, which was applied for amendment delivery in subsurface remediation.« less

Phytoscreening as an efficient tool to delineate chlorinated solvent sources at a chlor-alkali facility.

PubMed

Yung, Loïc; Lagron, Jérôme; Cazaux, David; Limmer, Matt; Chalot, Michel

2017-05-01

Chlorinated ethenes (CE) are among the most common volatile organic compounds (VOC) that contaminate groundwater, currently representing a major source of pollution worldwide. Phytoscreening has been developed and employed through different applications at numerous sites, where it was generally useful for detection of subsurface chlorinated solvents. We aimed at delineating subsurface CE contamination at a chlor-alkali facility using tree core data that we compared with soil data. For this investigation a total of 170 trees from experimental zones was sampled and analyzed for perchloroethene (PCE) and trichloroethene (TCE) concentrations, measured by solid phase microextraction gas chromatography coupled to mass spectrometry. Within the panel of tree genera sampled, Quercus and Ulmus appeared to be efficient biomonitors of subjacent TCE and PCE contamination, in addition to the well known and widely used Populus and Salix genera. Among the 28 trees located above the dense non-aqueous phase liquid (DNAPL) phase zone, 19 tree cores contained detectable amounts of CE, with concentrations ranging from 3 to 3000 μg L -1 . Our tree core dataset was found to be well related to soil gas sampling results, although the tree coring data were more informative. Our data further emphasized the need for choosing the relevant tree species and sampling periods, as well as taking into consideration the nature of the soil and its heterogeneity. Overall, this low-invasive screening method appeared useful to delineate contaminants at a small-scale site impacted by multiple sources of chlorinated solvents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reactive Oxygen Species are Ubiquitous along Subsurface Redox Gradients

NASA Astrophysics Data System (ADS)

Nico, P. S.; Yuan, X.; Davis, J. A.; Dwivedi, D.; Williams, K. H.; Bhattacharyya, A.; Fox, P. M.

2016-12-01

Reactive oxygen species (hydroxyl radical, superoxide, hydrogen peroxide, etc.) are known to be important intermediates in many biological and earth system processes. They have been particularly well studied in the realms of atmospheric chemistry and aquatic photochemistry. However, recently there is increasing evidence that they are also present in impactful quantities in dark systems as a result of both biotic and abiotic reactions. Herein we will present a complementary suite of laboratory and field studies examining the presence and production of hydrogen peroxide under relevant subsurface conditions. The laboratory work examines the redox cycling between reduced organic matter, molecular oxygen, and Fe which results in not only the production of hydrogen peroxide and oxidation of organic functional groups but also the maintenance of steady-state concentration of Fe(II) under fully oxygenated aqueous conditions. The field studies involve three distinct locations, namely a shallow subsurface aquifer, a hyporheic zone redox gradient across a river meander, and a hillside shale seep. In all cases detectable quantities (tens of nanomolar) of hydrogen peroxide were measured. In general, concentrations peak under transitional redox conditions where there is the simultaneous presence of reduced Fe, organic matter, and at least trace dissolved oxygen. Many, but not all, of the observed dynamics in hydrogen peroxide production can be reproduced by a simple kinetic model representing the reactions between Fe, organic matter, and molecular oxygen, but many questions remain regarding the role of microorganisms and other redox active chemical species in determining the detected hydrogen peroxide concentrations. The consistent detection of hydrogen peroxide at these disparate locations supports the hypothesis that hydrogen peroxide, and by extension, the entire suite of reactive oxygen species are ubiquitous along subsurface redox gradients.

DEVELOPMENT OF AN IN SITU THERMAL EXTRACTION DETECTION SYSTEM (TEDS) FOR RAPID, ACCURATE, QUANTITATIVE ANALYSIS OF ENVIRONMENTAL POLLUTANTS IN THE SUBSURFACE - PHASE I

EPA Science Inventory

Ion Signature Technology, Inc. (IST) will develop and market a collection and analysis system that will retrieve soil-bound pollutants as well as soluble and non-soluble contaminants from groundwater as the probe is pushed by cone penetrometry of Geoprobe into the subsurface. ...

Final Report: Molecular Mechanisms of Interfacial Reactivity in Near Surface and Extreme Geochemical Environments (DE-SC0009362)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixon, David A

2016-03-27

The prediction of the long-term stability and safety of geologic sequestration of greenhouse gases requires a detailed understanding of subsurface transport and chemical interactions between the disposed greenhouse gases and the geologic media. In this regard, mineral-fluid interactions are of prime importance since reactions that occur on or near the interface can assist in the long term sequestration of CO2 by trapping in mineral phases such as carbonates, as well as influencing the subsurface migration of the disposed fluids via creation or plugging of pores or fractures in the host rock strata. Previous research on mineral-fluid interaction for subsurface CO2more » storage has focused almost entirely on the aqueous phase, i.e., reactivity with aqueous solutions or brines containing dissolved CO2. However, interactions with neat to water-saturated non-aqueous fluids are of equal if not greater importance since supercritical CO2 (scCO2) is less dense than the aqueous phase or oil which will create a buoyant scCO2 plume that ultimately will dominate the pore volume within the caprock, and the injected scCO2 will contain water soon after injection and this water can be highly reactive. Collectively, therefore, mineral interactions with water-saturated scCO2-dominated fluids are pivotal and could result in the stable sequestration of CO2 by trapping in mineral phases such as metal carbonates within otherwise permeable zones in the caprock. The primary objective is to unravel the molecular mechanisms governing the reactivity of mineral phases important in the geologic sequestration of CO2 with variably wet supercritical carbon dioxide as a function of T, P, and mineral structure using computational chemistry. This work is in close collaboration with the PNNL Geosciences effort. The focus of the work at The University of Alabama is computational studies of the formation of magnesium and calcium carbonates and oxides and their reactivity and providing computational support of the experimental efforts at PNNL, especially for energetics, structural properties, and interpretation of spectra.« less

Quantification of the Mass Transfer at Fluid Interfaces in Microfluidic Channels

NASA Astrophysics Data System (ADS)

Wismeth, Carina; Manhart, Michael; Niessner, Reinhard; Baumann, Thomas

2017-04-01

Mass transfer rates at interfaces in a complex porous media are relevant in many environmental applications and control the functions of natural filter systems in subsurface environments. The mass transfer at fluid interfaces is associated with interface convection caused by local inhomogeneities in interface tension and hydrodynamic instabilities at the interface. If there is a surface tension gradient along the surface a shear stress jump is generated that results in fluid motion along the surface that is called Marangoni effect. These spontaneous convection currents can lead to an increased mass transfer of the transition component at the phase boundary and to an increased mixing of the phases. Therefore compensatory currents at the interface can have a significant influence on the subsurface transport of contaminants in the groundwater area, especially in the vadose zone. Using microfluidic channels and advanced experimental techniques it is possible to measure the fluid flow and mass transfer rates directly and to quantify the effect of the Marangoni convection on the mass transfer at interfaces between a non-aqueous liquid and water with high temporal and spatial resolution. The use of fluorescent particles as well as the recording and analysis of their trajectories is intended to visualize interfacial processes and to quantify the mass transfer at fluid phase boundaries. Concentration gradients at the interface are analysed by spectroscopic methods and allow an assessment of the enrichment and depletion at the phase boundaries. Extensive test series provide the experimental basis for quantifying and analysing the impact of the Marangoni effect on the mass transfer rates at interfaces in porous media in subsurface aquatic environments. Within this research project we concentrate on the effect of Marangoni convection on the mass transfer near an 1-octanol-water interface, which serves as a well defined proxy for non-aqueous phase liquids in porous media. Experiments and a numerical simulation are closely coupled to provide a generic data set with high reproducibility and used to obtain highly resolved three-dimensional data of mass transfer in two- and three-phase systems to foster the understanding of subsurface transport, especially in the vadose zone.

PCE solubilization and mobilization by commercial humic acid

NASA Astrophysics Data System (ADS)

Johnson, William P.; John, W. Wynn

1999-01-01

In this paper, comparison is made of terms describing solubilization of hydrophobic organic compounds (HOC) by dissolved humic substances (DHS) and commercial non-ionic surfactants. This paper examines the ability of a commercial humic acid (Aldrich humic acid) to solubilize and mobilize tetrachlorothene (PCE) residual in porous media. The constant for solubilization of PCE by Aldrich humic acid is shown to be a factor of two to thirty times less than that published for dodecyl alcohol ethoxylate surfactants, showing that Aldrich humic acid is less capable than some non-ionic surfactants at solubilizing residual PCE. The depression of PCE-water interfacial tension in the presence of DHS is shown to be significantly less than published values for a non-ionic surfactant, and surfactant mixtures, indicating that the DHS used in this study is less prone to cause mobilization of non-aqueous phase liquids relative to surfactants. Several possible advantages of DHS use in the remediation of subsurface media contaminated with HOC are described, including the ability of DHS to solubilize HOC irrespective of the DHS concentration, and potential lesser tendency of DHS to depress the interfacial tension between non-aqueous phases and water relative to surfactants (an advantage when mobilization is undesired).

High-Frequency Electromagnetic Impedance Measurements for Characterization, Monitoring and Verification Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Ki Ha; Becker, Alex; Tseng, Hung-Wen

2004-06-16

Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic (EM) measurements at frequencies between 0.1 and 100 MHz are important for such applications, because the induction number of many targets is small and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high-resolution imaging, accurate measurements are necessary so the field data canmore » be mapped into the space of the subsurface parameters. We are developing a non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using the EM impedance approach (Frangos, 2001; Lee and Becker, 2001; Song et al., 2002, Tseng et al., 2003). Electric and magnetic sensors are being tested and calibrated on sea water and in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques.« less

A high frequency electromagnetic impedance imaging system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tseng, Hung-Wen; Lee, Ki Ha; Becker, Alex

2003-01-15

Non-invasive, high resolution geophysical mapping of the shallow subsurface is necessary for delineation of buried hazardous wastes, detecting unexploded ordinance, verifying and monitoring of containment or moisture contents, and other environmental applications. Electromagnetic (EM) techniques can be used for this purpose since electrical conductivity and dielectric permittivity are representative of the subsurface media. Measurements in the EM frequency band between 1 and 100 MHz are very important for such applications, because the induction number of many targets is small and the ability to determine the subsurface distribution of both electrical properties is required. Earlier workers were successful in developing systemsmore » for detecting anomalous areas, but quantitative interpretation of the data was difficult. Accurate measurements are necessary, but difficult to achieve for high-resolution imaging of the subsurface. We are developing a broadband non-invasive method for accurately mapping the electrical conductivity and dielectric permittivity of the shallow subsurface using an EM impedance approach similar to the MT exploration technique. Electric and magnetic sensors were tested to ensure that stray EM scattering is minimized and the quality of the data collected with the high-frequency impedance (HFI) system is good enough to allow high-resolution, multi-dimensional imaging of hidden targets. Additional efforts are being made to modify and further develop existing sensors and transmitters to improve the imaging capability and data acquisition efficiency.« less

Roadside IED detection using subsurface imaging radar and rotary UAV

NASA Astrophysics Data System (ADS)

Qin, Yexian; Twumasi, Jones O.; Le, Viet Q.; Ren, Yu-Jiun; Lai, C. P.; Yu, Tzuyang

2016-05-01

Modern improvised explosive device (IED) and mine detection sensors using microwave technology are based on ground penetrating radar operated by a ground vehicle. Vehicle size, road conditions, and obstacles along the troop marching direction limit operation of such sensors. This paper presents a new conceptual design using a rotary unmanned aerial vehicle (UAV) to carry subsurface imaging radar for roadside IED detection. We have built a UAV flight simulator with the subsurface imaging radar running in a laboratory environment and tested it with non-metallic and metallic IED-like targets. From the initial lab results, we can detect the IED-like target 10-cm below road surface while carried by a UAV platform. One of the challenges is to design the radar and antenna system for a very small payload (less than 3 lb). The motion compensation algorithm is also critical to the imaging quality. In this paper, we also demonstrated the algorithm simulation and experimental imaging results with different IED target materials, sizes, and clutters.

Compatibility of Surfactants and Thermally Activated Persulfate for Enhanced Subsurface Remediation.

PubMed

Wang, Li; Peng, Libin; Xie, Liling; Deng, Peiyan; Deng, Dayi

2017-06-20

Limited aqueous availability of hydrophobic organic contaminants and nonaqueous phase liquids in subsurface environment may seriously impair the effectiveness of traditional in situ chemical oxidation (ISCO). To tackle the issue, a combination of surfactants and thermally activated persulfate was proposed to enhance the aqueous availability and consequent oxidation of organic contaminants. The compatibility of eight representative nonionic, monovalent anionic, and divalent anionic surfactants with persulfate at various temperatures was first studied, to identify suitable surfactants that have high aqueous stability and low oxidant demands to couple with thermally activated persulfate. C 12 -MADS (sodium dodecyl diphenyl ether disulfonate, a representative divalent anionic surfactant) stands out as the most compatible surfactant. Batch treatability study with coal tar, an example of challenging scenarios for traditional ISCO, was then conducted. The results show that C 12 -MADS can significantly enhance not only the oxidation of polyaromatic hydrocarbons contained in coal tar but also oxidant utilization efficiency, indicating the potential of the proposed coupling process for the treatment of organic contaminants with low aqueous availability.

Ammonia, phosphate, phenol, and copper(II) removal from aqueous solution by subsurface and surface flow constructed wetland.

PubMed

Mojiri, Amin; Ahmad, Zakiah; Tajuddin, Ramlah Mohd; Arshad, Mohd Fadzil; Gholami, Ali

2017-07-01

Water pollution is a global problem. During current study, ammonia, phosphate, phenol, and copper(II) were removed from aqueous solution by subsurface and surface flow constructed wetland. In current investigation, distilled water was polluted with four contaminants including ammonia, phosphate, copper (Cu), and phenol. Response surface methodology and central composite design were applied to optimize pollutant removal during treatment by subsurface flow constructed wetland (SSFCW). Contact time (12 to 80 h) and initial pollutant concentration (20 to 85 mg/L) were selected as independent factors; some upper and lower ranges were also monitored for accuracy. In SSFCW, water hyacinth transplanted in two substrate layers, namely zeolite and cockle shell. SSFCW removed 87.7, 81.4, 74.7, and 54.9% of ammonia, phosphate, Cu, and phenol, respectively, at optimum contact time (64.5 h) and initial pollutant concentration (69.2 mg/L). Aqueous solution was moved to a surface flow constructed wetland (SFCW) after treating via SSFCW at optimum conditions. In SFCW, Typha was transplanted to a fixed powdered substrate layer, including bentonite, zeolite, and cockle shell. SFCW could develop performance of this combined system and could improve elimination efficacy of the four contaminants to 99.99%. So this combined CW showed a good performance in removing pollutants. Graphical abstract Wetlands arrangement for treating aqueous solution in current study.

Band edge engineering of oxide photoanodes for photoelectrochemical water splitting: Integration of subsurface dipoles with atomic-scale control

DOE PAGES

Hikita, Yasuyuki; Nishio, Kazunori; Seitz, Linsey C.; ...

2016-01-22

One of the crucial parameters dictating the efficiency of photoelectrochemical water-splitting is the semiconductor band edge alignment with respect to hydrogen and oxygen redox potentials. Despite the importance of metal oxides in their use as photoelectrodes, studies to control the band edge alignment in aqueous solution have been limited predominantly to compound semiconductors with modulation ranges limited to a few hundred mV. The ability to modulate the flat band potential of oxide photoanodes by as much as 1.3 V, using the insertion of subsurface electrostatic dipoles near a Nb-doped SrTiO 3/aqueous electrolyte interface is reported. Lastly, the tunable range achievedmore » far exceeds previous reports in any semiconductor/aqueous electrolyte system and suggests a general design strategy for highly efficient oxide photoelectrodes.« less

Imaging of Subsurface Corrosion Using Gradient-Field Pulsed Eddy Current Probes with Uniform Field Excitation

PubMed Central

Ren, Shuting; Yan, Bei; Zainal Abidin, Ilham Mukriz; Wang, Yi

2017-01-01

A corrosive environment leaves in-service conductive structures prone to subsurface corrosion which poses a severe threat to the structural integrity. It is indispensable to detect and quantitatively evaluate subsurface corrosion via non-destructive evaluation techniques. Although the gradient-field pulsed eddy current technique (GPEC) has been found to be superior in the evaluation of corrosion in conductors, it suffers from a technical drawback resulting from the non-uniform field excited by the conventional pancake coil. In light of this, a new GPEC probe with uniform field excitation for the imaging of subsurface corrosion is proposed in this paper. The excited uniform field makes the GPEC signal correspond only to the field perturbation due to the presence of subsurface corrosion, which benefits the corrosion profiling and sizing. A 3D analytical model of GPEC is established to analyze the characteristics of the uniform field induced within a conductor. Following this, experiments regarding the imaging of subsurface corrosion via GPEC have been carried out. It has been found from the results that the proposed GPEC probe with uniform field excitation not only applies to the imaging of subsurface corrosion in conductive structures, but provides high-sensitivity imaging results regarding the corrosion profile and opening size. PMID:28758985

Imaging of Subsurface Corrosion Using Gradient-Field Pulsed Eddy Current Probes with Uniform Field Excitation.

PubMed

Li, Yong; Ren, Shuting; Yan, Bei; Zainal Abidin, Ilham Mukriz; Wang, Yi

2017-07-31

A corrosive environment leaves in-service conductive structures prone to subsurface corrosion which poses a severe threat to the structural integrity. It is indispensable to detect and quantitatively evaluate subsurface corrosion via non-destructive evaluation techniques. Although the gradient-field pulsed eddy current technique (GPEC) has been found to be superior in the evaluation of corrosion in conductors, it suffers from a technical drawback resulting from the non-uniform field excited by the conventional pancake coil. In light of this, a new GPEC probe with uniform field excitation for the imaging of subsurface corrosion is proposed in this paper. The excited uniform field makes the GPEC signal correspond only to the field perturbation due to the presence of subsurface corrosion, which benefits the corrosion profiling and sizing. A 3D analytical model of GPEC is established to analyze the characteristics of the uniform field induced within a conductor. Following this, experiments regarding the imaging of subsurface corrosion via GPEC have been carried out. It has been found from the results that the proposed GPEC probe with uniform field excitation not only applies to the imaging of subsurface corrosion in conductive structures, but provides high-sensitivity imaging results regarding the corrosion profile and opening size.

Identification and characterization of natural pipe systems in forested tropical soils

NASA Astrophysics Data System (ADS)

Bovi, Renata Cristina; Moreira, Cesar Augusto; Stucchi Boschi, Raquel; Cooper, Miguel

2017-04-01

Erosive processes on soil surface have been well studied and comprehended by several researchers, however little is known about subsurface erosive processes (piping). Piping is a type of subsurface erosion caused by water flowing in the subsurface and is still considered one of the most difficult erosive processes to be studied. Several processes have been considered as resposible for subsurface erosion and their interaction is complex and difficult to be studied separately. Surface investigations on their own may underestimate the erosion processes, due to the possible occurrence of subsurface processes that are not yet exposed on the surface. The network of subsurface processes should also be understood to better control erosion. Conservation practices that focus on water runoff control may be inefficient if the subsurface flow is not considered. In this study, we aimed to identify and characterize subsurface cavities in the field, as well as understand the network of these cavities, by using geophysical methods (electrical tomography). The study area is situated at the Experimental Station of Tupi, state of São Paulo, Brazil. The soil of the area was classified as Hapludults. The area presents several erosive features, ranging from laminar to permanent gullies and subsurface erosions. The geophysical equipment used was the Terrameter LS resistivity meter, manufactured by ABEM Instruments. The method of electrical tomography was efficient to detect collapsed and non-collapsed pipes. The results presented valuable information to detect areas of risk.

Analytical solutions for efficient interpretation of single-well push-pull tracer tests

NASA Astrophysics Data System (ADS)

Huang, Junqi; Christ, John A.; Goltz, Mark N.

2010-08-01

Single-well push-pull tracer tests have been used to characterize the extent, fate, and transport of subsurface contamination. Analytical solutions provide one alternative for interpreting test results. In this work, an exact analytical solution to two-dimensional equations describing the governing processes acting on a dissolved compound during a modified push-pull test (advection, longitudinal and transverse dispersion, first-order decay, and rate-limited sorption/partitioning in steady, divergent, and convergent flow fields) is developed. The coupling of this solution with inverse modeling to estimate aquifer parameters provides an efficient methodology for subsurface characterization. Synthetic data for single-well push-pull tests are employed to demonstrate the utility of the solution for determining (1) estimates of aquifer longitudinal and transverse dispersivities, (2) sorption distribution coefficients and rate constants, and (3) non-aqueous phase liquid (NAPL) saturations. Employment of the solution to estimate NAPL saturations based on partitioning and non-partitioning tracers is designed to overcome limitations of previous efforts by including rate-limited mass transfer. This solution provides a new tool for use by practitioners when interpreting single-well push-pull test results.

Are There Oceans Under the Ice of Small Saturnian and Uranian Moons?

NASA Astrophysics Data System (ADS)

England, C.

2003-05-01

Thermal analysis of the large outer-planetary moons (Titan, Callisto, Ganymede) argue strongly for substantial subsurface oceans if they are made up mostly of rock and ice, and if the rock exhibits radioactivity not too different from that of meteoric and lunar material [1]. For Titania, Rhea, Oberon and Iapetus (the TROI moons) with radii just over 700 km, the existence of oceans is less clear. In these bodies, a subsurface ocean may be likely if the rock has sunk to the center of the moon (i.e., the moon is differentiated) and (1) the radiogenic heating rate is on the higher end of that of lunar samples, (2) the bodies experience tidal heating, or (3) the oceans contain compounds such as ammonia that reduce the freezing point of the aqueous environment. A combination of these occurrences would weigh for a subsurface ocean, perhaps of substantial size. That outer-planetary moons with radii larger than about 200 km (e.g.; Enceladus at 250 km) are spherical argues for separation of light and heavy materials, especially in the larger bodies. Otherwise, the moon exhibits an irregular shape (e.g.; Hyperion at 133 km). Primordial radioactivity and collision events may have aided separation. If present-day radiogenicity is that of lunar samples, natural heating is available to maintain global aqueous environments on all of the TROI moons. The ammonia-water eutectics suggested for Titan [2] provide additional margin. The maintenance of oceans in smaller bodies depends on a balance of internal heat generation and thermal isolation by ice or other insulating material. The more important parameter may be the insulating ice, without which an outer-planetary ocean is not possible. The reduced thermal conductivity for impure ice [3] provides even more likelihood for oceans. Calculations for tidal heating within Europa due to orbital resonances [4] suggest that tidal heating amounts to over 40 times its internal radiogenic heating. A value equal only to natural radiogenic heating would be sufficient to maintain aqueous systems within TROI moons. Subsurface aqueous oceans are likely on Titania, Rhea, Oberon and Iapetus, but will be buried more than 300 km under insulating icy layers. Their existence, and that of an environment favorable for life, may be detectable from surface features or from remote surveys of their internal electromagnetic properties. [1] England C, DPS MEETING #34 Abstract #41.08, 9/2002 [2] Lorenz RD, Lunine JI, McKay CP, ENANTIOMER 6 (2-3): 83-96 2001 [3] Lorenz RD and Shandera SE, GEOPHYSICAL RESEARCH LETTERS 28 (2) 215-218 2001 [4] Ross MN, Schubert G, LUNAR AND PLANETARY SCIENCE XVII, PP. 724-725, 1986

THE DETERMINATION OF NON-PESTICIDAL AND PESTICIDAL ORGANOTIN COMPOUNDS IN WATER BY GAS CHROMATOGRAPHY WITH [PULSED] FLAME PHOTOMETRIC DETECTION (GS/PFPD): THE EFFECTS OF "MASS" DISCRIMINATION

EPA Science Inventory

Capillary gas chromatography with GC/PFPD was used in the development of analytical methodology for determining both non-pesticidal and pesticidal organotin compounds in drinking water and other aqueous matrices. The method involves aqueous ethylation of organotin analytes with ...

Impact of Moisture Content and Grain Size on Hydrocarbon Diffusion in Porous Media

NASA Astrophysics Data System (ADS)

McLain, A. A.; Ho, C. K.

2001-12-01

Diffusion of hydrocarbon vapors in porous media can play an important role in our ability to characterize subsurface contaminants such as trichloroethylene (TCE). For example, traditional monitoring methods often rely on direct sampling of contaminated soils or vapor. These samples may be influenced by the diffusion of vapors away from the contaminant source term, such as non-aqueous-phase TCE liquid. In addition, diffusion of hydrocarbon vapors can also impact the migration and dispersion of the contaminant in the subsurface. Therefore, understanding the diffusion rates and vapor transport processes of hydrocarbons in variably-saturated, heterogeneous porous media will assist in the characterization and detection of these subsurface contaminants. The purpose of this study was to investigate the impact of soil heterogeneity and water-moisture content on the diffusion processes for TCE. A one-dimensional column experiment was used to monitor the rates of vapor diffusion through sand. Experiments were performed with different average water-moisture contents and different grain sizes. On one end of the column, a reservoir cap is used to encase the TCE, providing a constant vapor boundary condition while sealing the end. The other end of the column contains a novel microchemical sensor. The sensor employs a polymer-absorption resistor (chemiresistor) that reversibly swells and increases in resistance when exposed to hydrocarbons. Once calibrated, the chemiresistors can be used to passively monitor vapor concentrations. This unique method allows the detection of in-situ vapor concentrations without disturbing the local environment. Results are presented in the form of vapor-concentration breakthrough curves as detected by the sensor. The shape of the breakthrough curve is dependent on several key parameters, including the length of the column and parameters (e.g., water-moisture content and grain-size) that affect the effective diffusion coefficient of TCE in air. Comparisons are made between theoretical and observed breakthrough curves to evaluate the diffusion of TCE and other relevant physical processes (e.g., air-water partitioning of TCE). The relative impact of water-moisture content and grain size on the diffusion of TCE vapor in porous media is also addressed. The authors thank Bob Hughes, who developed the chemiresistor sensors, and Chad Davis, who assisted with the calibrations. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

1987 Nuclear Science Symposium, 34th, and 1987 Symposium on Nuclear Power Systems, 19th, San Francisco, CA, Oct. 21-23, 1987, Proceedings

NASA Astrophysics Data System (ADS)

Armantrout, Guy A.

1988-02-01

The present conference consideres topics in radiation detectors, advanced electronic circuits, data acquisition systems, radiation detector systems, high-energy and nuclear physics radiation detection, spaceborne instrumentation, health physics and environmental radiation detection, nuclear medicine, nuclear well logging, and nuclear reactor instrumentation. Attention is given to the response of scintillators to heavy ions, phonon-mediated particle detection, ballistic deficits in pulse-shaping amplifiers, fast analog ICs for particle physics, logic cell arrays, the CERN host interface, high performance data buses, a novel scintillating glass for high-energy physics applications, background events in microchannel plates, a tritium accelerator mass spectrometer, a novel positron tomograph, advancements in PET, cylindrical positron tomography, nuclear techniques in subsurface geology, REE borehole neutron activation, and a continuous tritium monitor for aqueous process streams.

Clues on Past Climatic Environments and Subsurface Flow in Mars from Aqueous Alteration Minerals Found in Nakhla and Allan Hills 84001 Meteorites

NASA Astrophysics Data System (ADS)

Trigo-Rodriguez, J. M.; Moyano-Cambero, C. E.; Donoso, J. A.; Benito-Moreno, M. I.; Alonso-Azcárate, J.

2018-04-01

The study of aqueous alteration minerals like Fe-Mg-Ca carbonates in Allan Hills 84001 or iddingsite and magnetite in Nakhla meteorite allow us to constrain their formation conditions and water availability at 4 and 1.3 Ga ago, respectively.

Hints of Habitable Environments on Mars Challenge Our Studies of Mars-Analog Sites on Earth

NASA Technical Reports Server (NTRS)

desMarais, David J

2009-01-01

Life as we know it requires water with a chemical activity (alpha) >or approx.0.6 and sources of nutrients and useful energy. Some biota can survive even if favorable conditions occur only intermittently, but the minimum required frequency of occurrences is poorly understood. Recent discoveries have vindicated the Mars exploration strategy to follow the water. Mars Global Surveyor s Thermal Emission Spectrometer (TES) found coarse-grained hematite at Meridiani Planum. Opportunity rover confirmed this and also found evidence of ancient sulfate-rich playa lakes and near-surface groundwater. Elsewhere, TES found evidence of evaporitic halides in topographic depressions. But alpha might not have approached 0.6 in these evaporitic sulfate- and halide-bearing waters. Mars Express (MEX) and Mars Reconnaissance Orbiter (MRO) found extensive sulfate evaporites in Meridiani and Valles Marineris. MEX found phyllosilicates at several sites, most notably Mawrth Valles and Nili Fossae. MRO's CRISM near-IR mapper extended the known diversity and geographic distribution of phyllosilicates to include numerous Noachian craters. Phyllosilicates typically occur at the base of exposed ancient rock sections or in sediments in early Hesperian craters. It is uncertain whether the phyllosilicates developed in surface or subsurface aqueous environments and how long aqueous conditions persisted. Spirit rover found remarkably pure ferric sulfate, indicating oxidation and transport of Fe and S, perhaps in fumaroles or hot springs. Spirit also found opaline silica, consistent with hydrothermal activity. CRISM mapped extensive silica deposits in the Valles Marineris region, consistent with aqueous weathering and deposition. CRISM also found ultramafic rocks and magnesite at Nili Fossae, consistent with serpentinization, a process that can sustain habitable environments on Earth. The report of atmospheric methane implies subsurface aqueous conditions. A working hypothesis is that aqueous environments persisted in the near-subsurface for hundreds of millions of years and might exist even today. Studies of Mars-analog environments must better understand subsurface nonphotosynthetic ecosystems and their biosignatures in mafic and ultramafic terranes. Studies must determine minimum needs for water activity and energy and also establish survival limits when conditions that support active metabolism and propagation become progressively less frequent over time.

Detection of stiff nanoparticles within cellular structures by contact resonance atomic force microscopy subsurface nanomechanical imaging.

PubMed

Reggente, Melania; Passeri, Daniele; Angeloni, Livia; Scaramuzzo, Francesca Anna; Barteri, Mario; De Angelis, Francesca; Persiconi, Irene; De Stefano, Maria Egle; Rossi, Marco

2017-05-04

Detecting stiff nanoparticles buried in soft biological matrices by atomic force microscopy (AFM) based techniques represents a new frontier in the field of scanning probe microscopies, originally developed as surface characterization methods. Here we report the detection of stiff (magnetic) nanoparticles (NPs) internalized in cells by using contact resonance AFM (CR-AFM) employed as a potentially non-destructive subsurface characterization tool. Magnetite (Fe 3 O 4 ) NPs were internalized in microglial cells from cerebral cortices of mouse embryos of 18 days by phagocytosis. Nanomechanical imaging of cells was performed by detecting the contact resonance frequencies (CRFs) of an AFM cantilever held in contact with the sample. Agglomerates of NPs internalized in cells were visualized on the basis of the local increase in the contact stiffness with respect to the surrounding biological matrix. A second AFM-based technique for nanomechanical imaging, i.e., HarmoniX™, as well as magnetic force microscopy and light microscopy were used to confirm the CR-AFM results. Thus, CR-AFM was demonstrated as a promising technique for subsurface imaging of nanomaterials in biological samples.

Occurrence of select perfluoroalkyl substances at U.S. Air Force aqueous film-forming foam release sites other than fire-training areas: Field-validation of critical fate and transport properties.

PubMed

Anderson, R Hunter; Long, G Cornell; Porter, Ronald C; Anderson, Janet K

2016-05-01

The use of aqueous film-forming foam (AFFF) to extinguish hydrocarbon-based fires is recognized as a significant source of environmental poly- and perfluoroalkyl substances (PFASs). Although the occurrence of select PFASs in soil and groundwater at former fire-training areas (FTAs) at military installations operable since 1970 has been consistently confirmed, studies reporting the occurrence of PFASs at other AFFF-impacted sites (e.g. emergency response locations, AFFF lagoons, hangar-related AFFF storage tanks and pipelines, and fire station testing and maintenance areas) are largely missing from the literature. Further, studies have mostly focused on a single site (i.e., FTAs at military installations) and, thus, lack a comparison of sites with diverse AFFF release history. Therefore, the purpose of this investigation was to evaluate select PFAS occurrence at non-FTA sites on active U.S. Air Force installations with historic AFFF use of varying magnitude. Concentrations of fifteen perfluoroalkyl acids (PFAAs) and perfluorooctane sulfonamide (PFOSA), an important PFOS precursor, were measured from several hundred samples among multiple media (i.e., surface soil, subsurface soil, sediment, surface water, and groundwater) collected from forty AFFF-impacted sites across ten installations between March and September 2014, representing one of the most comprehensive datasets on environmental PFAS occurrence to date. Differences in detection frequencies and observed concentrations due to AFFF release volume are presented along with rigorous data analyses that quantitatively demonstrate phase-dependent (i.e., solid-phase vs aqueous-phase) differences in the chemical signature as a function of carbon chain-length and in situ PFOS (and to a slightly lesser extent PFHxS) formation, presumably due to precursor biotransformation. Published by Elsevier Ltd.

Phytoremediation removal rates of benzene, toluene, and chlorobenzene.

PubMed

Limmer, Matt A; Wilson, Jordan; Westenberg, David; Lee, Amy; Siegman, Mark; Burken, Joel G

2018-06-07

Phytoremediation is a sustainable remedial approach, although performance efficacy is rarely reported. In this study, we assessed a phytoremediation plot treating benzene, toluene, and chlorobenzene. A comparison of the calculated phytoremediation removal rate with estimates of onsite contaminant mass was used to forecast cleanup periods. The investigation demonstrated that substantial microbial degradation was occurring in the subsurface. Estimates of transpiration indicated that the trees planted were removing approximately 240,000 L of water per year. This large quantity of water removal implies substantial removal of contaminant due to large amounts of contaminants in the groundwater; however, these contaminants extensively sorb to the soil, resulting in large quantities of contaminant mass in the subsurface. The total estimate of subsurface contaminant mass was also complicated by the presence of non-aqueous phase liquids (NAPL), additional contaminant masses that were difficult to quantify. These uncertainties of initial contaminant mass at the site result in large uncertainty in the cleanup period, although mean estimates are on the order of decades. Collectively, the model indicates contaminant removal rates on the order of 10 -2 -10 0 kg/tree/year. The benefit of the phytoremediation system is relatively sustainable cleanup over the long periods necessary due to the presence of NAPL.

Large scale and long term application of bioslurping: the case of a Greek petroleum refinery site.

PubMed

Gidarakos, E; Aivalioti, M

2007-11-19

This paper presents the course and the remediation results of a 4-year application of bioslurping technology on the subsurface of a Greek petroleum refinery, which is still under full operation and has important and complicated subsurface contamination problems, mainly due to the presence of light non-aqueous phase liquids (LNAPL). About 55 wells are connected to the central bioslurping unit, while a mobile bioslurping unit is also used whenever and wherever is necessary. Moreover, there are about 120 additional wells for the monitoring of the subsurface of the facilities that cover a total area of 1,000,000 m(2). An integrated monitoring program has also been developed and applied on the site, including frequent LNAPL layer depth and thickness measurements, conduction of bail-down and recovery tests, sampling and chemical analysis of the free oil phase, etc., so as to evaluate the remediation technique's efficiency and ensure a prompt tracing of any new potential leak. Despite the occurrence of new leaks within the last 4 years and the observed entrapment of LNAPL in the vadoze zone, bioslurping has managed to greatly restrict the original plume within certain and relatively small parts of the refinery facilities.

Sorption of imazaquin in soils with positive balance of charges.

PubMed

Rocha, Wadson S D; Regitano, Jussara B; Alleoni, Luis R F; Tornisielo, Valdemar L

2002-10-01

The herbicide imazaquin has both an acid and a basic ionizable groups, and its sorption depends upon the pH, the electric potential (psi0), and the oxide and the organic carbon (OC) contents of the soil. Sorption and extraction experiments using 14C-imazaquin were performed in surface and subsurface samples of two acric oxisols (an anionic "rhodic" acrudox and an anionic "xanthic" acrudox) and one non-acric alfisol (a rhodic kandiudalf), treated at four different pH values. Imazaquin showed low to moderate sorption to the soils. Sorption decreased and aqueous extraction increased as pH increased. Up to pH 5.8, sorption was higher in subsurface than in surface layers of the acric soils, due to the positive balance of charges resulted from the high Fe and Al oxide and the low OC contents. It favored electrostatic interactions with anionic molecules of imazaquin. For the subsurface samples of these highly weathered soils, where psi0 was positive and OC was low, it was not possible to predict sorption just by considering imazaquin speciation and its hydrophobic partition to the organic domains of the soil. Moreover, if Koc measured for thesurface samples were assumed to represent the whole profile in predictive models for leaching potential, then it would result in underestimation of sorption potential in subsurface, and consequently result in overestimation of the leaching potential.

A partially coupled, fraction-by-fraction modelling approach to the subsurface migration of gasoline spills

NASA Astrophysics Data System (ADS)

Fagerlund, F.; Niemi, A.

2007-01-01

The subsurface spreading behaviour of gasoline, as well as several other common soil- and groundwater pollutants (e.g. diesel, creosote), is complicated by the fact that it is a mixture of hundreds of different constituents, behaving differently with respect to e.g. dissolution, volatilisation, adsorption and biodegradation. Especially for scenarios where the non-aqueous phase liquid (NAPL) phase is highly mobile, such as for sudden spills in connection with accidents, it is necessary to simultaneously analyse the migration of the NAPL and its individual components in order to assess risks and environmental impacts. Although a few fully coupled, multi-phase, multi-constituent models exist, such models are highly complex and may be time consuming to use. A new, somewhat simplified methodology for modelling the subsurface migration of gasoline while taking its multi-constituent nature into account is therefore introduced here. Constituents with similar properties are grouped together into eight fractions. The migration of each fraction in the aqueous and gaseous phases as well as adsorption is modelled separately using a single-constituent multi-phase flow model, while the movement of the free-phase gasoline is essentially the same for all fractions. The modelling is done stepwise to allow updating of the free-phase gasoline composition at certain time intervals. The output is the concentration of the eight different fractions in the aqueous, gaseous, free gasoline and solid phases with time. The approach is evaluated by comparing it to a fully coupled multi-phase, multi-constituent numerical simulator in the modelling of a typical accident-type spill scenario, based on a tanker accident in northern Sweden. Here the PCFF method produces results similar to those of the more sophisticated, fully coupled model. The benefit of the method is that it is easy to use and can be applied to any single-constituent multi-phase numerical simulator, which in turn may have different strengths in incorporating various processes. The results demonstrate that the different fractions have significantly different migration behaviours and although the methodology involves some simplifications, it is a considerable improvement compared to modelling the gasoline constituents completely individually or as one single mixture.

Modelling biofilm-induced formation damage and biocide treatment in subsurface geosystems

PubMed Central

Ezeuko, C C; Sen, A; Gates, I D

2013-01-01

Biofilm growth in subsurface porous media, and its treatment with biocides (antimicrobial agents), involves a complex interaction of biogeochemical processes which provide non-trivial mathematical modelling challenges. Although there are literature reports of mathematical models to evaluate biofilm tolerance to biocides, none of these models have investigated biocide treatment of biofilms growing in interconnected porous media with flow. In this paper, we present a numerical investigation using a pore network model of biofilm growth, formation damage and biocide treatment. The model includes three phases (aqueous, adsorbed biofilm, and solid matrix), a single growth-limiting nutrient and a single biocide dissolved in the water. Biofilm is assumed to contain a single species of microbe, in which each cell can be a viable persister, a viable non-persister, or non-viable (dead). Persisters describe small subpopulation of cells which are tolerant to biocide treatment. Biofilm tolerance to biocide treatment is regulated by persister cells and includes ‘innate’ and ‘biocide-induced’ factors. Simulations demonstrate that biofilm tolerance to biocides can increase with biofilm maturity, and that biocide treatment alone does not reverse biofilm-induced formation damage. Also, a successful application of biological permeability conformance treatment involving geologic layers with flow communication is more complicated than simply engineering the attachment of biofilm-forming cells at desired sites. PMID:23164434

Effects of nitrate on the stability of uranium in a bioreduced region of the subsurface.

PubMed

Wu, Wei-Min; Carley, Jack; Green, Stefan J; Luo, Jian; Kelly, Shelly D; Van Nostrand, Joy; Lowe, Kenneth; Mehlhorn, Tonia; Carroll, Sue; Boonchayanant, Benjaporn; Löfller, Frank E; Watson, David; Kemner, Kenneth M; Zhou, Jizhong; Kitanidis, Peter K; Kostka, Joel E; Jardine, Philip M; Criddle, Craig S

2010-07-01

The effects of nitrate on the stability of reduced, immobilized uranium were evaluated in field experiments at a U.S. Department of Energy site in Oak Ridge, TN. Nitrate (2.0 mM) was injected into a reduced region of the subsurface containing high levels of previously immobilized U(IV). The nitrate was reduced to nitrite, ammonium, and nitrogen gas; sulfide levels decreased; and Fe(II) levels increased then deceased. Uranium remobilization occurred concomitant with nitrite formation, suggesting nitrate-dependent, iron-accelerated oxidation of U(IV). Bromide tracer results indicated changes in subsurface flowpaths likely due to gas formation and/or precipitate. Desorption-adsorption of uranium by the iron-rich sediment impacted uranium mobilization and sequestration. After rereduction of the subsurface through ethanol additions, background groundwater containing high levels of nitrate was allowed to enter the reduced test zone. Aqueous uranium concentrations increased then decreased. Clone library analyses of sediment samples revealed the presence of denitrifying bacteria that can oxidize elemental sulfur, H(2)S, Fe(II), and U(IV) (e.g., Thiobacillus spp.), and a decrease in relative abundance of bacteria that can reduce Fe(III) and sulfate. XANES analyses of sediment samples confirmed changes in uranium oxidation state. Addition of ethanol restored reduced conditions and triggered a short-term increase in Fe(II) and aqueous uranium, likely due to reductive dissolution of Fe(III) oxides and release of sorbed U(VI). After two months of intermittent ethanol addition, sulfide levels increased, and aqueous uranium concentrations gradually decreased to <0.1 microM.

Application of 4D resistivity image profiling to detect DNAPLs plume.

NASA Astrophysics Data System (ADS)

Liu, H.; Yang, C.; Tsai, Y.

2008-12-01

In July 1993, the soil and groundwater of the factory of Taiwan , Miaoli was found to be contaminated by dichloroethane, chlorobenzene and other hazardous solvents. The contaminants were termed to be dense non-aqueous phase liquids (DNAPLs). The contaminated site was neglected for the following years until May 1998, the Environment Protection Agency of Miaoli ordered the company immediately take an action for treatment of the contaminated site. Excavating and exposing the contaminated soil was done at the previous waste DNAPL dumped area. In addition, more than 53 wells were drilled around the pool with a maximum depth of 12 m where a clayey layer was found. Continuous pumping the groundwater and monitoring the concentration of residual DNAPL contained in the well water samples have done in different stages of remediation. However, it is suspected that the DNAPL has existed for a long time, therefore the contaminants might dilute but remnants of a DNAPL plume that are toxic to humans still remain in the soil and migrate to deeper aquifers. A former contaminated site was investigated using the 2D, 3D and 4D resisitivity image technique, with aims of determining buried contaminant geometry. This paper emphasizes the use of resistivity image profiling (RIP) method to map the limit of this DNAPL waste disposal site where the records of operations are not variations. A significant change in resistivity values was detected between known polluted and non-polluted subsurface; a high resistivity value implies that the subsurface was contaminated by DNAPL plume. The results of the survey serve to provide insight into the sensitivity of RIP method for detecting DNAPL plumes within the shallow subsurface, and help to provide valuable information related to monitoring the possible migration path of DNAPL plume in the past. According to the formerly studies in this site, affiliation by excavates with pumps water remediation had very long time, Therefore this research was used iron nanoparticles with pumps water remediation ways. The survey lines use the same length and the same position of the different time observation. The survey lines monitors the iron nanoparticles and pollution flow direction with remediation effect. By used the iron nanoparticles and pumping water remediation ways, the DNAPL plumes had eminent changed. Iron nanoparticles granule is smaller than the micron iron, Therefore the reaction rate was quite quick at the iron nanoparticles and pumps, but the ferric oxide can cause the electronic resistivity to elevate produces after the response. Pumps water rectifies may remove the ferric oxide to cause the electronic resistivity to reduce. The iron nanoparticles and pollution response is extremely obviously of the Resistivity Image Profile.

Applicability of grid-net detection system for landfill leachate and diesel fuel release in the subsurface.

PubMed

Oh, Myounghak; Seo, Min Woo; Lee, Seunghak; Park, Junboum

2008-02-19

The grid-net system estimating the electrical conductivity changes was evaluated as a potential detection system for the leakage of diesel fuel and landfill leachate. Aspects of electrical conductivity changes were varied upon the type of contaminant. The electrical conductivity in the homogeneous mixtures of soil and landfill leachate linearly increased with the ionic concentration of pore fluid, which became more significant at higher volumetric water contents. However, the electrical conductivity in soil/diesel fuel mixture decreased with diesel fuel content and it was more significant at lower water contents. The electrode spacing should be determined by considering the type of contaminant to enhance the electrode sensitivity especially when two-electrode sensors are to be used. The electrode sensitivity for landfill leachate was constantly maintained regardless of the electrode spacings while that for the diesel fuel significantly increased at smaller electrode spacings. This is possibly due to the fact that the insulating barrier effect of the diesel fuel in non-aqueous phase was less predominant at large electrode spacing because electrical current can form the round-about paths over the volume with relatively small diesel fuel content. The model test results showed that the grid-net detection system can be used to monitor the leakage from waste landfill and underground storage tank sites. However, for a successful application of the detection system in the field, data under various field conditions should be accumulated.

Numerical modeling of subsurface radioactive solute transport from waste seepage ponds at the Idaho National Engineering Laboratory

USGS Publications Warehouse

Robertson, John B.

1976-01-01

Aqueous chemical and low-level radioactive effluents have been disposed to seepage ponds since 1952 at the Idaho National Engineering Laboratory. The solutions percolate toward the Snake River Plain aquifer (135 m below) through interlayered basalts and unconsolidated sediments and an extensive zone of ground water perched on a sedimentary layer about 40 m beneath the ponds. A three-segment numerical model was developed to simulate the system, including effects of convection, hydrodynamic dispersion, radioactive decay, and adsorption. Simulated hydraulics and solute migration patterns for all segments agree adequately with the available field data. The model can be used to project subsurface distributions of waste solutes under a variety of assumed conditions for the future. Although chloride and tritium reached the aquifer several years ago, the model analysis suggests that the more easily sorbed solutes, such as cesium-137 and strontium-90, would not reach the aquifer in detectable concentrations within 150 years for the conditions assumed. (Woodard-USGS)

In situ chemical stimulation of diatomite formations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, B.W.

1989-05-09

A method is described of recovering hydrocarbon from a subsurface diatomite formation comprising the steps of: a. introducing an aqueous surface solution into the diatomite formation, the aqueous surface active solution comprising (i) a diatomite/oil/ water wettability improving agent, and (ii) an oil/water interfacial tension lowering agent; and b. producing oil from the diatomite formation.

Methanogenesis-induced pH–Eh shifts drives aqueous metal(loid) mobility in sulfide mineral systems under CO2 enriched conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, Omar R.; Qafoku, Nikolla; Cantrell, Kirk J.

2016-01-15

Accounting for microbially-mediated CO2 transformation is pivotal to assessing geochemical implications for elevated CO2 in subsurface environments. A series of batch-reactor experiments were conducted to decipher links between autotrophic methanogenesis, CO2 dynamics and aqueous Fe, As and Pb concentrations in the presence of sulfide minerals. Microbially-mediated solubility-trapping followed by pseudo-first order reduction of HCO3- to CH4 (k’ = 0.28-0.59 d-1) accounted for 95% of the CO2 loss from methanogenic experiments. Bicarbonate-to-methane reduction was pivotal in the mitigation of CO2-induced acidity (~1 pH unit) and enhancement of reducing conditions (Eh change from -0.215 to -0.332V ). Methanogenesis-associated shifts in pH-Eh valuesmore » showed no significant effect on aqueous Pb but favored, 1) increased aqueous As as a result of microbially-mediated dissolution of arsenopyrite and 2) decreased aqueous Fe due to mineral-trapping of CO2-mobilized Fe as Fe-carbonate. Its order of occurrence (and magnitude), relative to solubility- and mineral-trapping, highlighted the potential for autotrophic methanogenesis to modulate both carbon sequestration and contaminant mobility in CO2-impacted subsurface environments.« less

Coupled geophysical-hydrological modeling of controlled NAPL spill

NASA Astrophysics Data System (ADS)

Kowalsky, M. B.; Majer, E.; Peterson, J. E.; Finsterle, S.; Mazzella, A.

2006-12-01

Past studies have shown reasonable sensitivity of geophysical data for detecting or monitoring the movement of non-aqueous phase liquids (NAPLs) in the subsurface. However, heterogeneity in subsurface properties and in NAPL distribution commonly results in non-unique data interpretation. Combining multiple geophysical data types and incorporating constraints from hydrological models will potentially decrease the non-uniqueness in data interpretation and aid in site characterization. Large-scale laboratory experiments have been conducted over several years to evaluate the use of various geophysical methods, including ground-penetrating radar (GPR), seismic, and electrical methods, for monitoring controlled spills of tetrachloroethylene (PCE), a hazardous industrial solvent that is pervasive in the subsurface. In the current study, we consider an experiment in which PCE was introduced into a large tank containing a heterogeneous distribution of sand and clay mixtures, and allowed to migrate while time-lapse geophysical data were collected. We consider two approaches for interpreting the surface GPR and crosswell seismic data. The first approach involves (a) waveform inversion of the surface GPR data using a non-gradient based optimization algorithm to estimate the dielectric constant distributions and (b) conversion of crosswell seismic travel times to acoustic velocity distributions; the dielectric constant and acoustic velocity distributions are then related to NAPL saturation using appropriate petrophysical models. The second approach takes advantage of a recently developed framework for coupled hydrological-geophysical modeling, providing a hydrological constraint on interpretation of the geophysical data and additionally resulting in quantitative estimates of the most relevant hydrological parameters that determine NAPL behavior in the system. Specifically, we simulate NAPL migration using the multiphase multicomponent flow simulator TOUGH2 with a 2-D radial model that takes advantage of radial symmetry in the experimental setup. The flow model is coupled to forward models for simulating the GPR and seismic measurements, and joint inversion of the multiple data types results in images of time-varying NAPL saturation distributions. Comparison of the two approaches with results of the post-experiment excavation indicate that combining geophysical data types and incorporating hydrological constraints improves estimates of NAPL saturation relative to the conventional interpretation of the geophysical data sets. Notice: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect the official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation by EPA for use. This work was supported, in part, by the U.S. Dept. of Energy under Contract No. DE-AC02- 05CH11231.

[Study of free radicals in aqueous humor in glaucoma and cataracts: differences in presence or absence of diabetes mellitus and neovascular glaucoma].

PubMed

Oshida, Eiki; Arai, Kiyomi; Sakai, Miki; Chikuda, Makoto

2014-09-01

This study was conducted for the purpose of comparing differences in the types of free radicals in the aqueous humor of glaucoma and cataract patients. Free radicals in the aqueous humor of 44 glaucoma eyes and 15 cataract eyes were measured by electron spin resonance (ESR), followed by comparing the detection rates. In addition, subgroup analyses were also conducted for the presence or absence of complications of diabetes mellitus (DM) and neovascular glaucoma (NVG) in the patients. Three types of free radicals were measured, ascorbate-free radical (AFR), AFR containing a trace amount of superoxide (SO) (AFR +), and SO containing a trace amount of AFR (SO +). Significant differences were observed in the detection rates of each type between the glaucoma group (maximum SO +) and the cataract group (maximum AFR), between the DM group (maximum SO +) and the non-DM group (maximum AFR) in the glaucoma, and between the DM group (maximum AFR +) and the non-DM group (maximum AFR) in the cataract. SO + was detected in all cases of NVG regardless of whether they were DM or non-DM. Glaucoma cases are more susceptible to the generation of SO in the aqueous humor than cataracts, and they are more liable to occur in DM than in non-DM in both glaucoma and cataract cases. This study suggest an evidence for a strong correlation with SO and vascularization in NVG.

Theoretical study of the influence of chemical reactions and physical parameters on the convective dissolution of CO2 in aqueous solutions

NASA Astrophysics Data System (ADS)

Loodts, Vanessa; Rongy, Laurence; De Wit, Anne

2014-05-01

Subsurface carbon sequestration has emerged as a promising solution to the problem of increasing atmospheric carbon dioxide (CO2) levels. How does the efficiency of such a sequestration process depend on the physical and chemical characteristics of the storage site? This question is emblematic of the need to better understand the dynamics of CO2 in subsurface formations, and in particular, the properties of the convective dissolution of CO2 in the salt water of aquifers. This dissolution is known to improve the safety of the sequestration by reducing the risks of leaks of CO2 to the atmosphere. Buoyancy-driven convection makes this dissolution faster by transporting dissolved CO2 further away from the interface. Indeed, upon injection, the less dense CO2 phase rises above the aqueous layer where it starts to dissolve. The dissolved CO2 increases the density of the aqueous solution, thereby creating a layer of denser CO2-rich solution above less dense solution. This unstable density gradient in the gravity field is at the origin of convection. In this framework, we theoretically investigate the effect of CO2 pressure, salt concentration, temperature, and chemical reactions on the dissolution-driven convection of CO2 in aqueous solutions. On the basis of a linear stability analysis, we assess the stability of the time-dependent density profiles developing when CO2 dissolves in an aqueous layer below it. We predict that increasing CO2 pressure destabilizes the system with regard to buoyancy-driven convection, because it increases the density gradient at the origin of the instability. By contrast, increasing salt concentration or temperature stabilizes the system via effects on CO2 solubility, solutal expansion coefficient, diffusion coefficient and on the viscosity and density of the solution. We also show that a reaction of CO2 with chemical species dissolved in the aqueous solution can either enhance or decrease the amplitude of the convective dissolution compared to the non reactive one. On the basis of a reaction-diffusion-convection model, we classify the various possible cases and show that the difference between the solutal expansion coefficients of the reactant and of the product governs the type of density profile building up in the aqueous solution and thus the stability of the system. By contrast to non reactive density profiles, reactive density profiles can feature a minimum that induces a delay of the buoyancy-driven convection. This work identifies the parameters that could influence the dissolution-driven convection in the aquifers, and thus impact the safety of the sequestration. In other words, this theoretical study shows that it is crucial to analyse the composition and reactivity of potential storage sites to choose those that will be most efficient for long-term CO2 sequestration.

On-line identification of 3,4-methylenedioxymethamphetamine in human urine by non-aqueous capillary electrophoresis-fluorescence spectroscopy at 77 K.

PubMed

Chung, Y L; Liu, J T; Lin, C H

2001-08-15

The analytical profiles for 3,4-methylenedioxymethamphetamine (3,4-MDMA) and related amphetamines in urine samples are described for non-aqueous capillary electrophoresis-fluorescence spectroscopy. 3,4-MDMA was detected and identified on-line, using a cryogenic molecular fluorescence technique at 77 K. Under optimized conditions, baseline separation of the selected compounds was achieved in less than 12 min. Precision was evaluated by measuring the repeatability and intermediate precision of the migration times and corrected peak areas. The non-aqueous CE separation conditions and the spectral characteristics of 3,4-MDMA with respect to solvent and temperature effects are also discussed.

Growth of microorganisms in Martian-like shallow subsurface conditions: laboratory modelling

NASA Astrophysics Data System (ADS)

Pavlov, A. K.; Shelegedin, V. N.; Vdovina, M. A.; Pavlov, A. A.

2010-01-01

Low atmospheric pressures on Mars and the lack of substantial amounts of liquid water were suggested to be among the major limiting factors for the potential Martian biosphere. However, large amounts of ice were detected in the relatively shallow subsurface layers of Mars by the Odyssey Mission and when ice sublimates the water vapour can diffuse through the porous surface layer of the soil. Here we studied the possibility for the active growth of microorganisms in such a vapour diffusion layer. Our results showed the possibility of metabolism and the reproduction of non-extremophile terrestrial microorganisms (Vibrio sp.) under very low (0.01-0.1 mbar) atmospheric pressures in a Martian-like shallow subsurface regolith.

PCR detection of groundwater bacteria associated with colloidal transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cruz-Perez, P.; Stetzenbach, L.D.; Alvarez, A.J.

1996-02-29

Colloidal transport may increase the amount of contaminant material than that which could be transported by water flow alone. The role of colloids in groundwater contaminant transport is complicated and may involve many different processes, including sorption of elements onto colloidal particles, coagulation/dissolution, adsorption onto solid surfaces, filtration, and migration. Bacteria are known to concentrate minerals and influence the transport of compounds in aqueous environments and may also serve as organic colloids, thereby influencing subsurface transport of radionuclides and other contaminants. The initial phase of the project consisted of assembling a list of bacteria capable of sequestering or facilitating mineralmore » transport. The development and optimization of the PCR amplification assay for the detection of the organisms of interest, and the examination of regional groundwaters for those organisms, are presented for subsequent research.« less

Accurate determination of non-metallic impurities in high purity tetramethylammonium hydroxide using inductively coupled plasma tandem mass spectrometry

NASA Astrophysics Data System (ADS)

Fu, Liang; Xie, Hualin; Shi, Shuyun; Chen, Xiaoqing

2018-06-01

The content of non-metallic impurities in high-purity tetramethylammonium hydroxide (HPTMAH) aqueous solution has an important influence on the yield, electrical properties and reliability of the integrated circuit during the process of chip etching and cleaning. Therefore, an efficient analytical method to directly quantify the content of non-metallic impurities in HPTMAH aqueous solutions is necessary. The present study was aimed to develop a novel method that can accurately determine seven non-metallic impurities (B, Si, P, S, Cl, As, and Se) in an aqueous solution of HPTMAH by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). The samples were measured using a direct injection method. In the MS/MS mode, oxygen and hydrogen were used as reaction gases in the octopole reaction system (ORS) to eliminate mass spectral interferences during the analytical process. The detection limits of B, Si, P, S, Cl, As, and Se were 0.31, 0.48, 0.051, 0.27, 3.10, 0.008, and 0.005 μg L-1, respectively. The samples were analyzed by the developed method and the sector field inductively coupled plasma mass spectrometry (SF-ICP-MS) was used for contrastive analysis. The values of these seven elements measured using ICP-MS/MS were consistent with those measured by SF-ICP-MS. The proposed method can be utilized to analyze non-metallic impurities in HPTMAH aqueous solution. Table S2 Multiple potential interferences on the analytes. Table S3 Parameters of calibration curve and the detection limit (DL). Table S4 Results obtained for 25% concentration high-purity grade TMAH aqueous solution samples (μg L-1, mean ± standard deviation, n = 10).

From surface to intracellular non-invasive nanoscale study of living cells impairments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ewald, Dr. Maxime; Tetard, Laurene; Elie-Caille, Dr. Cecile

Among the enduring challenges in nanoscience, subsurface characterization of live cells holds major stakes. Developments in nanometrology for soft matter thriving on the sensitivity and high resolution benefits of atomic force microscopy have enabled detection of subsurface structures at the nanoscale (1,2,3). However, measurements in liquid environments remain complex (4,5,6,7), in particular in the subsurface domain. Here we introduce liquid-Mode Synthesizing Atomic Force Microscopy (l-MSAFM) to study both the inner structures and the chemically induced intracellular impairments of living cells. Specifically, we visualize the intracellular stress effects of glyphosate on living keratinocytes skin cells. This new approach for living cellmore » nanoscale imaging, l-MSAFM, in their physiological environment or in presence of a chemical stress agent confirmed the loss of inner structures induced by glyphosate. The ability to monitor the cell's inner response to external stimuli, non-destructively and in real time, has the potential to unveil critical nanoscale mechanisms of life science.« less

From surface to intracellular non-invasive nanoscale study of living cells impairments

NASA Astrophysics Data System (ADS)

Ewald, M.; Tetard, L.; Elie-Caille, C.; Nicod, L.; Passian, A.; Bourillot, E.; Lesniewska, E.

2014-07-01

Among the enduring challenges in nanoscience, subsurface characterization of living cells holds major stakes. Developments in nanometrology for soft matter thriving on the sensitivity and high resolution benefits of atomic force microscopy have enabled detection of subsurface structures at the nanoscale. However, measurements in liquid environments remain complex, in particular in the subsurface domain. Here we introduce liquid-mode synthesizing atomic force microscopy (l-MSAFM) to study both the inner structures and the chemically induced intracellular impairments of living cells. Specifically, we visualize the intracellular stress effects of glyphosate on living keratinocytes skin cells. This new approach, l-MSAFM, for nanoscale imaging of living cell in their physiological environment or in presence of a chemical stress agent could resolve the loss of inner structures induced by glyphosate, the main component of a well-known pesticide (RoundUp™). This firsthand ability to monitor the cell’s inner response to external stimuli non-destructively and in liquid, has the potential to unveil critical nanoscale mechanisms of life science.

Demonstration of Combined Zero-Valent Iron and Electrical Resistance Heating for In Situ Trichloroethene Remediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Truex, Michael J.; Macbeth, Tamzen; Vermeul, Vincent R.

The effectiveness of in situ treatment using zero-valent iron to remediate sites with non-aqueous phase or significant sediment-associated contaminant mass can be limited by relatively low rates of mass transfer to bring contaminants in contact with the reactive media. For a field test in a trichloroethene source area, combining moderate-temperature (maximum 50oC) subsurface electrical resistance heating with in situ ZVI treatment was shown to accelerate dechlorination and dissolution rates by a factor of 4 to 6 based on organic daughter products and a factor 8-16 using a chloride concentrations. A mass-discharge-based analysis was used to evaluate reaction, dissolution, and volatilizationmore » at ambient groundwater temperature (~10oC) and as temperature was increased up to about 50oC. Increased reaction and contaminant dissolution were observed with increased temperature, but volatilization was minimal during the test because in situ reactions maintained low aqueous-phase TCE concentrations.« less

Emerging non-invasive Raman methods in process control and forensic applications.

PubMed

Macleod, Neil A; Matousek, Pavel

2008-10-01

This article reviews emerging Raman techniques (Spatially Offset and Transmission Raman Spectroscopy) for non-invasive, sub-surface probing in process control and forensic applications. New capabilities offered by these methods are discussed and several application examples are given including the non-invasive detection of counterfeit drugs through blister packs and opaque plastic bottles and the rapid quantitative analysis of the bulk content of pharmaceutical tablets and capsules without sub-sampling.

Incorporation of Np(V) and U(VI) in Carbonate and Sulfate Minerals Crystallized from Aqueous Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balboni, Enrica; Morrison, Jessica M.; Wang, Zheming

2015-02-15

The neptunyl Np(V)O2 + and uranyl U(VI)O2 2+ ions are soluble in groundwater, although their interaction with minerals in the subsurface may impact their mobility. One mechanism for the immobilization of actinyl ions in the subsurface is coprecipitation in low-temperature minerals that form naturally, or that are induced to form as part of a remediation strategy. Important differences in the crystal-chemical behavior of the Np(V) neptunyl and U(VI) uranyl ions suggest their behavior towards incorporation into growing crystals may differ significantly. Using a selection of low temperature minerals synthesized in aqueous systems under ambient conditions, this study examines the factorsmore » that impact the structural incorporation of the Np(V) neptunyl and U(VI) uranyl ions in carbonate and sulfate minerals.« less

Enhanced Amendment Delivery to Subsurface Using Shear Thinning Fluid and Aqueous Foam for Metal, Radionuclide, and NAPL Remediation

NASA Astrophysics Data System (ADS)

Zhong, L.; Szecsody, J.; Li, X.; Oostrom, M.; Truex, M.

2010-12-01

In many contamination sites, removal of contaminants by any active remediation efforts is not practical due to the high cost and technological limitations. Alternatively, in situ remediation is expected to be the most important remediation strategy. Delivery of reactive amendment to the contamination zone is essential for the reactions between the contaminants and remedial amendments to proceed in situ. It is a challenge to effectively deliver remedial amendment to the subsurface contamination source areas in both aquifer and vadose zone. In aquifer, heterogeneity induces fluid bypassing the low-permeability zones, resulting in certain contaminated areas inaccessible to the remedial amendment delivered by water injection, thus inhibiting the success of remedial operations. In vadose zone in situ remediation, conventional solution injection and infiltration for amendment delivery have difficulties to achieve successful lateral spreading and uniform distribution of the reactive media. These approaches also tend to displace highly mobile metal and radionuclide contaminants such as hexavalent chromium [Cr(VI)] and technetium (Tc-99), causing spreading of contaminations. Shear thinning fluid and aqueous foam can be applied to enhance the amendment delivery and improve in situ subsurface remediation efficiency under aquifer and vadose zone conditions, respectively. Column and 2-D flow cell experiments were conducted to demonstrate the enhanced delivery and improved remediation achieved by the application of shear thinning fluid and foam injection at the laboratory scale. Solutions of biopolymer xanthan gum were used as the shear thinning delivering fluids. Surfactant sodium lauryl ether sulfate (STEOL CS-330) was the foaming agent. The shear thinning fluid delivery (STFD) considerably improved the sweeping efficiency over a heterogeneous system and enhanced the non-aqueous liquid phase (NAPL) removal. The delivery of amendment into low-perm zones (LPZs) by STFD also increased the persistence of amendment solution in the LPZs after injection. Immobilization of Tc-99 was improved when a reductant was delivered by foam versus by water-based solution to contaminated vadose zone sediments. Foam delivery remarkably improved the lateral distribution of fluids compared to direct liquid injection. In heterogeneous vadose zone formation, foam injection increased the liquid flow in the high permeable zones into which very limited fluid was distributed during liquid infiltration, demonstrating improved amendment distribution uniformity in the heterogeneous system by foam delivery.

Detecting potential impacts of deep subsurface CO2 injection on shallow drinking water

NASA Astrophysics Data System (ADS)

Smyth, R. C.; Yang, C.; Romanak, K.; Mickler, P. J.; Lu, J.; Hovorka, S. D.

2012-12-01

Presented here are results from one aspect of collective research conducted at Gulf Coast Carbon Center, BEG, Jackson School at UT Austin. The biggest hurdle to public acceptance of CCS is to show that drinking water resources will not be impacted. Since late 1990s our group has been supported by US DOE NETL and private industry to research how best to detect potential impacts to shallow (0 to ~0.25 km) subsurface drinking water from deep (~1 to 3.5 km) injection of CO2. Work has and continues to include (1) field sampling and testing, (2) laboratory batch experiments, (3) geochemical modeling. The objective has been to identify the most sensitive geochemical indicators using data from research-level investigations, which can be economically applied on an industrial-scale. The worst-case scenario would be introduction of CO2 directly into drinking water from a leaking wellbore at a brownfield site. This is unlikely for a properly screened and/or maintained site, but needs to be considered. Our results show aquifer matrix (carbonate vs. clastic) to be critical to interpretation of pH and carbonate (DIC, Alkalinity, and δ13C of DIC) parameters because of the influence of water-rock reaction (buffering vs. non-buffering) on aqueous geochemistry. Field groundwater sampling sites to date are Cranfield, MS and SACROC, TX CO2-EOR oilfields. Two major aquifer types are represented, one dominated by silicate (Cranfield) and the other by carbonate (SACROC) water-rock reactions. We tested sensitivity of geochemical indicators (pH, DIC, Alkalinity, and δ13C of DIC) by modeling the effects of increasing pCO2 on aqueous geochemistry, and laboratory batch experiments, both with partial pressure of CO2 gas (pCO2) at 1x105 Pa (1 atm). Aquifer matrix and groundwater data provided constraints for the geochemical models. We used results from modeling and batch experiments to rank geochemical parameter sensitivity to increased pCO2 into weakly, mildly and strongly sensitive categories for both aquifer systems. DIC concentration is strongly sensitive to increased pCO2 for both aquifers; however, CO2 outgassing during sampling complicates direct field measurement of DIC. Interpretation of data from in-situ push-pull aquifer tests is ongoing and will be used to augment results summarized here. We are currently designing groundwater monitoring plans for two additional industrial-scale sites where we will further test the sensitivity and utility of our sampling approach.

Mapping Site Remediation with Electrical Resistivity Tomography Explored via Coupled-Model Simulations

NASA Astrophysics Data System (ADS)

Power, C.; Gerhard, J. I.; Tsourlos, P.; Giannopoulos, A.

2011-12-01

Remediation programs for sites contaminated with dense non-aqueous phase liquids (DNAPLs) would benefit from an ability to non-intrusively map the evolving volume and extent of the DNAPL source zone. Electrical resistivity tomography (ERT) is a well-established geophysical tool, widely used outside the remediation industry, that has significant potential for mapping DNAPL source zones. However, that potential has not been realized due to challenges in data interpretation from contaminated sites - in either a qualitative or quantitative way. The objective of this study is to evaluate the potential of ERT to map realistic, evolving DNAPL source zones within complex subsurface environments during remedial efforts. For this purpose, a novel coupled model was developed that integrates a multiphase flow model (DNAPL3D-MT), which generates realistic DNAPL release scenarios, with 3DINV, an ERT model which calculates the corresponding resistivity response. This presentation will describe the developed model coupling methodology, which integrates published petrophysical relationships to generate an electrical resistivity field that accounts for both the spatial heterogeneity of subsurface soils and the evolving spatial distribution of fluids (including permeability, porosity, clay content and air/water/DNAPL saturation). It will also present an example in which the coupled model was employed to explore the ability of ERT to track the remediation of a DNAPL source zone. A field-scale, three-dimensional release of chlorinated solvent DNAPL into heterogeneous clayey sand was simulated, including the subsurface migration and subsequent removal of the DNAPL source zone via dissolution in groundwater. Periodic surveys of this site via ERT applied at the surface were then simulated and inversion programs were used to calculate the subsurface distribution of electrical properties. This presentation will summarize this approach and its potential as a research tool exploring the range of site conditions under which ERT may prove useful in aiding DNAPL site remediation. Moreover, it is expected to provide a cost-effective avenue to test optimum ERT data acquisition, inversion and interpretative tools at contaminated sites.

Role of bacteria in the pathogenesis of recurrent uveitis in horses from the southeastern United States.

PubMed

Gilger, Brian C; Salmon, Jacklyn H; Yi, Na Y; Barden, Curtis A; Chandler, Heather L; Wendt, Jennifer A; Colitz, Carmen M H

2008-10-01

To determine the role of intraocular bacteria in the pathogenesis of equine recurrent uveitis (ERU) in horses from the southeastern United States by evaluating affected eyes of horses with ERU for bacterial DNA and intraocular production of antibodies against Leptospira spp. Aqueous humor, vitreous humor, and serum samples of 24 clinically normal horses, 52 horses with ERU, and 17 horses with ocular inflammation not associated with ERU (ie, non-ERU inflammation). Ribosomal RNA quantitative PCR (real-time PCR) assay was used to detect bacterial DNA in aqueous humor and vitreous humor from clinically normal horses (n = 12) and horses with chronic (> 3-month) ERU (28). Aqueous humor and serum were also evaluated for anti-Leptospira antibody titers from clinically normal horses (n = 12), horses with non-ERU inflammation (17), and horses with confirmed chronic ERU (24). Bacterial DNA was not detected in aqueous humor or vitreous humor of horses with ERU or clinically normal horses. No significant difference was found in titers of anti-Leptospira antibodies in serum or aqueous humor among these 3 groups. Only 2 horses, 1 horse with ERU and 1 horse with non-ERU inflammation, had definitive intraocular production of antibodies against Leptospira organisms. In horses from the southeastern United States, Leptospira organisms may have helped initiate ERU in some, but the continued presence of the organisms did not play a direct role in the pathogenesis of this recurrent disease.

Polymer coated gold nanoparticles for tracing the mobility of engineered nanoparticles in the subsurface

NASA Astrophysics Data System (ADS)

Uthuppu, Basil; Sidelmann Fjordbøge, Annika; Caspersen, Eva; Broholm, Mette Martina; Havsteen Jakobsen, Mogens

2014-05-01

Nanoparticles (NPs) are manufactured for their specific properties providing possibilities for new and improved products and applications. The use of engineered nanoparticles (ENPs) has therefore brought significant innovation and advances to society, including benefits for human health and the environment. At the same time, little is known about the potential risk associated with the inevitable release of these new materials to the environment, and their new properties are poorly understood . Suspensions of ENPs are not very stable, as they tend to aggregate thereby losing their properties as single particles. Coatings, including a large variety of natural and synthetic polymers, are used to enhance the colloid stability in high concentrations . However, increasing the stability of these materials may lead to unintended effects, such as enhancing their mobility in surface water and groundwater leading to inadvertent impacts on aquatic ecosystems and human health. Detection of ENPs in natural water systems, however, has proved very challenging. Hence, there is a need for tracing of ENP behaviour in the environment. We suggest a possibility of introducing inert gold NPs with the same mobility as the reactive NPs, as tracer particles. Colloidal gold has been of great interest for centuries due to its vibrant colors produced by the interaction with visible light. The unusual optical-electronic properties, high chemical stability and relatively low toxicity have made them the model system of choice in this context. Also, the natural occurrence of these particles in the proposed environment is very rare. Laboratory based experiments conducted in sand columns show that stable aqueous suspensions of gold NPs coated with amphiphilic block co polymers (PVP-VA and PVA-COOH) are extremely mobile (retardation factors of 1.0-1.2) with high recovery values (50-95 %). The specific retardation and recovery depends on the coating type, concentration and grafting method. The NPs also show significant partitioning to organic phases such as tetrachloroethylene (PCE) and trichloroethylene (TCE), which are considered as potential ground water pollutants accumulated in the subsurface as DNAPLs (dense non-aqueous phase liquids). Being a noble metal, nanogold is to be detected by nondestructive optical methods at a concentration of at least 1000 fold lower than ENPs. Using conventional spectrophotometric technique equipped with liquid waveguide capillary cell (LWCC), nanogold is detected at very low concentration range (1 ppm - 62.5 ppb). Compared to uncoated particles, surface modified nanogold with polymers retains the plasmonic peaks at 520 nm when diluted with artificial ground water. Acknowledgement: The low level detection of nanogold using LWCC was done at the department of nuclear and quantum engineering, KAIST (Korea Advance Institute of Science and Technology), 291 Daehak-ro, (373-1, Guseong-dong), Yuseong-gu, Daejeon 305-701, Republic of KOREA. We acknowledge Prof. Woojin Lee, Prof. Jong-Il Yun, Kim A Young and Tae Hyeong Kim for the same.

Sub-surface defects detection of by using active thermography and advanced image edge detection

NASA Astrophysics Data System (ADS)

Tse, Peter W.; Wang, Gaochao

2017-05-01

Active or pulsed thermography is a popular non-destructive testing (NDT) tool for inspecting the integrity and anomaly of industrial equipment. One of the recent research trends in using active thermography is to automate the process in detecting hidden defects. As of today, human effort has still been using to adjust the temperature intensity of the thermo camera in order to visually observe the difference in cooling rates caused by a normal target as compared to that by a sub-surface crack exists inside the target. To avoid the tedious human-visual inspection and minimize human induced error, this paper reports the design of an automatic method that is capable of detecting subsurface defects. The method used the technique of active thermography, edge detection in machine vision and smart algorithm. An infrared thermo-camera was used to capture a series of temporal pictures after slightly heating up the inspected target by flash lamps. Then the Canny edge detector was employed to automatically extract the defect related images from the captured pictures. The captured temporal pictures were preprocessed by a packet of Canny edge detector and then a smart algorithm was used to reconstruct the whole sequences of image signals. During the processes, noise and irrelevant backgrounds exist in the pictures were removed. Consequently, the contrast of the edges of defective areas had been highlighted. The designed automatic method was verified by real pipe specimens that contains sub-surface cracks. After applying such smart method, the edges of cracks can be revealed visually without the need of using manual adjustment on the setting of thermo-camera. With the help of this automatic method, the tedious process in manually adjusting the colour contract and the pixel intensity in order to reveal defects can be avoided.

Relating sub-surface ice features to physiological stress in a climate sensitive mammal, the American pika (Ochotona princeps).

PubMed

Wilkening, Jennifer L; Ray, Chris; Varner, Johanna

2015-01-01

The American pika (Ochotona princeps) is considered a sentinel species for detecting ecological effects of climate change. Pikas are declining within a large portion of their range, and ongoing research suggests loss of sub-surface ice as a mechanism. However, no studies have demonstrated physiological responses of pikas to sub-surface ice features. Here we present the first analysis of physiological stress in pikas living in and adjacent to habitats underlain by ice. Fresh fecal samples were collected non-invasively from two adjacent sites in the Rocky Mountains (one with sub-surface ice and one without) and analyzed for glucocorticoid metabolites (GCM). We also measured sub-surface microclimates in each habitat. Results indicate lower GCM concentration in sites with sub-surface ice, suggesting that pikas are less stressed in favorable microclimates resulting from sub-surface ice features. GCM response was well predicted by habitat characteristics associated with sub-surface ice features, such as lower mean summer temperatures. These results suggest that pikas inhabiting areas without sub-surface ice features are experiencing higher levels of physiological stress and may be more susceptible to changing climates. Although post-deposition environmental effects can confound analyses based on fecal GCM, we found no evidence for such effects in this study. Sub-surface ice features are key to water cycling and storage and will likely represent an increasingly important component of water resources in a warming climate. Fecal samples collected from additional watersheds as part of current pika monitoring programs could be used to further characterize relationships between pika stress and sub-surface ice features.

Transport, Targeting, and Applications of Metallic Functional Nanoparticles for Degradation of DNAPL Chlorinated Organic Solvents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregory V. Lowry; Sara Majetich; Krzysztof Matyjaszewski

2006-12-27

Dense Non-Aqueous Phase Liquid (DNAPL) such as trichloroethylene act as long term sources of groundwater contaminants and are difficult and expensive to remediate. DNAPL-contaminated sites are a significant financial liability for the Department of Energy and the private sector. The objective of this study was to engineer reactive Fe-based nanoparticles with specialized polymeric coatings to make them mobile in the subsurface and to provide them with an affinity for the DNAPL/water interface. The synthesis, characterization, and reactivity/mobility of the engineered particles, and a molecular dynamic model that predicts their behavior at the DNPAL/water interface are described in this report.

Chemical Sensors Based on IR Spectroscopy and Surface-Modified Waveguides

NASA Technical Reports Server (NTRS)

Lopez, Gabriel P.; Niemczyk, Thomas

1999-01-01

Sol-gel processing techniques have been used to apply thin porous films to the surfaces of planar infrared (IR) waveguides to produce widely useful chemical sensors. The thin- film coating serves to diminish the concentration of water and increase the concentration of the analyte in the region probed by the evanescent IR wave. These porous films are composed of silica, and therefore, conventional silica surface modification techniques can be used to give the surface a specific functional character. The sol-gel film was surface-modified to make the film highly hydrophobic. These sensors were shown to be capable of detecting non-polar organic analytes, such as benzonitrile, in aqueous solution with detection limits in the ppb range. Further, these porous sol-gel structures allow the analytes to diffuse into and out of the films rapidly, thus reaching equilibrium in less than ten seconds. These sensors are unique because of the fact that their operation is based on the measurement of an IR absorption spectrum. Thus, these sensors are able to identify the analytes as well as measure concentration with high sensitivity. These developments have been documented in previous reports and publications. Recently, we have also targeted detection of the polar organic molecules acetone and isopropanol in aqueous solution. Polar organics are widely used in industrial and chemical processes, hence it is of interest to monitor their presence in effluents or decontamination process flows. Although large improvements in detection limits were expected with non-polar organic molecules in aqueous solutions using very hydrophobic porous sol-gel films on silicon attenuated total reflectance (Si ATR) waveguides, it was not as clear what the detection enhancements might be for polar organic molecules. This report describes the use of modified sol-gel-coated Si ATR sensors for trace detection and quantitation of small polar organic molecules in aqueous solutions. The detection of both acetone and isopropanol molecules in aqueous solution has been previously reported for chalcogenide fiber optic sensors. The sol-gel film was produced using a mixture of ethyltriethoxysilane and tetraethoxysilane and the surface modification was carried out using trimethylchlorosilane. We have demonstrated that this film concentrates the target polar analytes from aqueous solution in the region probed by the evanescent wave to improve detection limits by as much as a factor of 450.

Dense Nonaqueous Phase Liquids at Former Manufactured Gas Plants: Challenges to Modeling and Remediation

PubMed Central

Birak, P.S.; Miller, C.T.

2008-01-01

The remediation of dense non-aqueous phase liquids (DNAPLs) in porous media continues to be one of the most challenging problems facing environmental scientists and engineers. Of all the environmentally relevant DNAPLs, tars in the subsurface at former manufactured gas plants (FMGP’s) pose one of the biggest challenges due to their complex chemical composition and tendency to alter wettability. To further our understanding of these complex materials, we consulted historic documentation to evaluate the impact of gas manufacturing on the composition and physicochemical nature of the resulting tars. In the recent literature, most work to date has been focused in a relatively narrow portion of the expected range of tar materials, which has yielded a bias toward samples of relatively low viscosity and density. In this work, we consider the dissolution and movement of tars in the subsurface, models used to predict these phenomena, and approaches used for remediation. We also explore the open issues and detail important gaps in our fundamental understanding of these extraordinarily complex systems that must be resolved to reach a mature level of understanding. PMID:19176266

Sorption of Perfluorochemicals to Matrices Relevant to Sites Impacted by Aqueous Film-Forming Foam

NASA Astrophysics Data System (ADS)

Sepulvado, J.; Higgins, C.

2011-12-01

Perfluorochemicals are a class of emerging contaminants consisting of fluorinated surfactants that are chemically and thermally stable and which contain a fluorocarbon tail that is both hydro- and oleophobic. Because of these unique properties, PFCs have a wide variety of uses including food paper packaging products, stain repellants, nonstick coatings, and aqueous film-forming foams (AFFF). At fire-training facilities, repeated application of AFFF is used to extinguish hydrocarbon fuel fires ignited for training purposes. The presence of perfluochemicals (PFCs) in groundwater as a result of repeated AFFF application at these facilities has been documented. Due to factors such as the recent push towards regulation of PFCs in drinking water, concerns have arisen about the fate of these compounds in the subsurface. Groundwater plumes containing PFC subclasses such as perfluorocarboxylic acids (PFCAs), perfluoroalkylsulfonates (PFAS), and fluorotelomer sulfonates (FtSs) in the μg/L to mg/L range have been detected. These plumes also may contain co-contaminants such as hydrocarbon fuel components and chlorinated solvents, some of which may exist as nonaqueous phase liquids (NAPL). This study examined the sorption of PFCs to soil and aquifer material across the concentration range applicable to AFFF-impacted sites (μg/L - mg/L) and looked at the impact of co-contaminants, including NAPL, on PFC sorption. PFC sorption was variable and indicated that similar to previous work on PFC sorption to sediment, subsurface PFC transport will depend on factors such as the sorbent organic carbon content, PFC subclass, solution chemistry, and PFC chain length.

Mountable eddy current sensor for in-situ remote detection of surface and sub-surface fatigue cracks

DOEpatents

Yepez, III, Esteban; Roach, Dennis P [Albuquerque, NM; Rackow, Kirk A [Albuquerque, NM; DeLong, Waylon A [Albuquerque, NM

2011-09-06

A wireless, integrated, mountable, portable, battery-operated, non-contact eddy current sensor that provides similar accuracy to 1970's laboratory scale equipment (e.g., a Hewlett-Packard GP4194A Impedance Analyzer) at a fraction of the size and cost.

A novel double-layer molecularly imprinted polymer film based surface plasmon resonance for determination of testosterone in aqueous media

NASA Astrophysics Data System (ADS)

Tan, Yuan; Jing, Lijing; Ding, Yonghong; Wei, Tianxin

2015-07-01

This work aimed to prepare a novel double-layer structure molecularly imprinted polymer film (MIF) on the surface plasmon resonance (SPR) sensor chips for detection of testosterone in aqueous media. The film was synthesized by in-situ UV photo polymerization. Firstly, the modification of gold surface of SPR chip was performed by 1-dodecanethiol. Then double-layer MIF was generated on the 1-dodecanethiol modified gold surface. The non-modified and imprinted surfaces were characterized by atomic force microscopy (AFM), fourier transform infrared (FTIR) spectroscopy and contact angle measurements. Analysis of SPR spectroscopy showed that the imprinted sensing film displayed good selectivity for testosterone compared to other analogues and the non-imprinted polymer film (NIF). Within the concentrations range of 1 × 10-12-1 × 10-8 mol/L, the coupling angle changes of SPR were linear with the negative logarithm of testosterone concentrations (R2 = 0.993). Based on a signal/noise ratio of three, the detection limit was estimated to be 10-12 mol/L. Finally, the developed MIF was successfully applied to the seawater detection of testosterone. The results in the experiments suggested that a combination of SPR sensing with MIF was a promising alternative method for detection of testosterone in aqueous media.

From Ground Truth to Space: Surface, Subsurface and Remote Observations Associated with Nuclear Test Detection

NASA Astrophysics Data System (ADS)

Sussman, A. J.; Anderson, D.; Burt, C.; Craven, J.; Kimblin, C.; McKenna, I.; Schultz-Fellenz, E. S.; Miller, E.; Yocky, D. A.; Haas, D.

2016-12-01

Underground nuclear explosions (UNEs) result in numerous signatures that manifest on a wide range of temporal and spatial scales. Currently, prompt signals, such as the detection of seismic waves provide only generalized locations and the timing and amplitude of non-prompt signals are difficult to predict. As such, research into improving the detection, location, and identification of suspect events has been conducted, resulting in advancement of nuclear test detection science. In this presentation, we demonstrate the scalar variably of surface and subsurface observables, briefly discuss current capabilities to locate, detect and characterize potential nuclear explosion locations, and explain how emergent technologies and amalgamation of disparate data sets will facilitate improved monitoring and verification. At the smaller scales, material and fracture characterization efforts on rock collected from legacy UNE sites and from underground experiments using chemical explosions can be incorporated into predictive modeling efforts. Spatial analyses of digital elevation models and orthoimagery of both modern conventional and legacy nuclear sites show subtle surface topographic changes and damage at nearby outcrops. Additionally, at sites where such technology cannot penetrate vegetative cover, it is possible to use the vegetation itself as both a companion signature reflecting geologic conditions and showing subsurface impacts to water, nutrients, and chemicals. Aerial systems based on RGB imagery, light detection and ranging, and hyperspectral imaging can allow for combined remote sensing modalities to perform pattern recognition and classification tasks. Finally, more remote systems such as satellite based synthetic aperture radar and satellite imagery are other techniques in development for UNE site detection, location and characterization.

Non-invasive glucose monitor

NASA Technical Reports Server (NTRS)

Lambert, James L. (Inventor); Borchert, Mark S. (Inventor)

2001-01-01

A non-invasive method for determining blood level of an analyte of interest, such as glucose, comprises: generating an excitation laser beam (e.g., at a wavelength of 700 to 900 nanometers); focusing the excitation laser beam into the anterior chamber of an eye of the subject so that aqueous humor in the anterior chamber is illuminated; detecting (preferably confocally detecting) a Raman spectrum from the illuminated aqueous humor; and then determining the blood glucose level (or the level of another analyte of interest) for the subject from the Raman spectrum. Preferably, the detecting step is followed by the step of subtracting a confounding fluorescence spectrum from the Raman spectrum to produce a difference spectrum; and determining the blood level of the analyte of interest for the subject from that difference spectrum, preferably using linear or nonlinear multivariate analysis such as partial least squares analysis. Apparatus for carrying out the foregoing method is also disclosed.

A Widely Applicable Silver Sol for TLC Detection with Rich and Stable SERS Features.

PubMed

Zhu, Qingxia; Li, Hao; Lu, Feng; Chai, Yifeng; Yuan, Yongfang

2016-12-01

Thin-layer chromatography (TLC) coupled with surface-enhanced Raman spectroscopy (SERS) has gained tremendous popularity in the study of various complex systems. However, the detection of hydrophobic analytes is difficult, and the specificity still needs to be improved. In this study, a SERS-active non-aqueous silver sol which could activate the analytes to produce rich and stable spectral features was rapidly synthesized. Then, the optimized silver nanoparticles (AgNPs)-DMF sol was employed for TLC-SERS detection of hydrophobic (and also hydrophilic) analytes. SERS performance of this sol was superior to that of traditional Lee-Meisel AgNPs due to its high specificity, acceptable stability, and wide applicability. The non-aqueous AgNPs would be suitable for the TLC-SERS method, which shows great promise for applications in food safety assurance, environmental monitoring, medical diagnoses, and many other fields.

A Widely Applicable Silver Sol for TLC Detection with Rich and Stable SERS Features

NASA Astrophysics Data System (ADS)

Zhu, Qingxia; Li, Hao; Lu, Feng; Chai, Yifeng; Yuan, Yongfang

2016-04-01

Thin-layer chromatography (TLC) coupled with surface-enhanced Raman spectroscopy (SERS) has gained tremendous popularity in the study of various complex systems. However, the detection of hydrophobic analytes is difficult, and the specificity still needs to be improved. In this study, a SERS-active non-aqueous silver sol which could activate the analytes to produce rich and stable spectral features was rapidly synthesized. Then, the optimized silver nanoparticles (AgNPs)-DMF sol was employed for TLC-SERS detection of hydrophobic (and also hydrophilic) analytes. SERS performance of this sol was superior to that of traditional Lee-Meisel AgNPs due to its high specificity, acceptable stability, and wide applicability. The non-aqueous AgNPs would be suitable for the TLC-SERS method, which shows great promise for applications in food safety assurance, environmental monitoring, medical diagnoses, and many other fields.

Relating Sub-Surface Ice Features to Physiological Stress in a Climate Sensitive Mammal, the American Pika (Ochotona princeps)

PubMed Central

Wilkening, Jennifer L.; Ray, Chris; Varner, Johanna

2015-01-01

The American pika (Ochotona princeps) is considered a sentinel species for detecting ecological effects of climate change. Pikas are declining within a large portion of their range, and ongoing research suggests loss of sub-surface ice as a mechanism. However, no studies have demonstrated physiological responses of pikas to sub-surface ice features. Here we present the first analysis of physiological stress in pikas living in and adjacent to habitats underlain by ice. Fresh fecal samples were collected non-invasively from two adjacent sites in the Rocky Mountains (one with sub-surface ice and one without) and analyzed for glucocorticoid metabolites (GCM). We also measured sub-surface microclimates in each habitat. Results indicate lower GCM concentration in sites with sub-surface ice, suggesting that pikas are less stressed in favorable microclimates resulting from sub-surface ice features. GCM response was well predicted by habitat characteristics associated with sub-surface ice features, such as lower mean summer temperatures. These results suggest that pikas inhabiting areas without sub-surface ice features are experiencing higher levels of physiological stress and may be more susceptible to changing climates. Although post-deposition environmental effects can confound analyses based on fecal GCM, we found no evidence for such effects in this study. Sub-surface ice features are key to water cycling and storage and will likely represent an increasingly important component of water resources in a warming climate. Fecal samples collected from additional watersheds as part of current pika monitoring programs could be used to further characterize relationships between pika stress and sub-surface ice features. PMID:25803587

Detection of Subsurface Defects in Levees in Correlation to Weather Conditions Utilizing Ground Penetrating Radar

NASA Astrophysics Data System (ADS)

Martinez, I. A.; Eisenmann, D.

2012-12-01

Ground Penetrating Radar (GPR) has been used for many years in successful subsurface detection of conductive and non-conductive objects in all types of material including different soils and concrete. Typical defect detection is based on subjective examination of processed scans using data collection and analysis software to acquire and analyze the data, often requiring a developed expertise or an awareness of how a GPR works while collecting data. Processing programs, such as GSSI's RADAN analysis software are then used to validate the collected information. Iowa State University's Center for Nondestructive Evaluation (CNDE) has built a test site, resembling a typical levee used near rivers, which contains known sub-surface targets of varying size, depth, and conductivity. Scientist at CNDE have developed software with the enhanced capabilities, to decipher a hyperbola's magnitude and amplitude for GPR signal processing. With this enhanced capability, the signal processing and defect detection capabilities for GPR have the potential to be greatly enhanced. This study will examine the effects of test parameters, antenna frequency (400MHz), data manipulation methods (which include data filters and restricting the range of depth in which the chosen antenna's signal can reach), and real-world conditions using this test site (such as varying weather conditions) , with the goal of improving GPR tests sensitivity for differing soil conditions.

Subsurface event detection and classification using Wireless Signal Networks.

PubMed

Yoon, Suk-Un; Ghazanfari, Ehsan; Cheng, Liang; Pamukcu, Sibel; Suleiman, Muhannad T

2012-11-05

Subsurface environment sensing and monitoring applications such as detection of water intrusion or a landslide, which could significantly change the physical properties of the host soil, can be accomplished using a novel concept, Wireless Signal Networks (WSiNs). The wireless signal networks take advantage of the variations of radio signal strength on the distributed underground sensor nodes of WSiNs to monitor and characterize the sensed area. To characterize subsurface environments for event detection and classification, this paper provides a detailed list and experimental data of soil properties on how radio propagation is affected by soil properties in subsurface communication environments. Experiments demonstrated that calibrated wireless signal strength variations can be used as indicators to sense changes in the subsurface environment. The concept of WSiNs for the subsurface event detection is evaluated with applications such as detection of water intrusion, relative density change, and relative motion using actual underground sensor nodes. To classify geo-events using the measured signal strength as a main indicator of geo-events, we propose a window-based minimum distance classifier based on Bayesian decision theory. The window-based classifier for wireless signal networks has two steps: event detection and event classification. With the event detection, the window-based classifier classifies geo-events on the event occurring regions that are called a classification window. The proposed window-based classification method is evaluated with a water leakage experiment in which the data has been measured in laboratory experiments. In these experiments, the proposed detection and classification method based on wireless signal network can detect and classify subsurface events.

Subsurface Event Detection and Classification Using Wireless Signal Networks

PubMed Central

Yoon, Suk-Un; Ghazanfari, Ehsan; Cheng, Liang; Pamukcu, Sibel; Suleiman, Muhannad T.

2012-01-01

Subsurface environment sensing and monitoring applications such as detection of water intrusion or a landslide, which could significantly change the physical properties of the host soil, can be accomplished using a novel concept, Wireless Signal Networks (WSiNs). The wireless signal networks take advantage of the variations of radio signal strength on the distributed underground sensor nodes of WSiNs to monitor and characterize the sensed area. To characterize subsurface environments for event detection and classification, this paper provides a detailed list and experimental data of soil properties on how radio propagation is affected by soil properties in subsurface communication environments. Experiments demonstrated that calibrated wireless signal strength variations can be used as indicators to sense changes in the subsurface environment. The concept of WSiNs for the subsurface event detection is evaluated with applications such as detection of water intrusion, relative density change, and relative motion using actual underground sensor nodes. To classify geo-events using the measured signal strength as a main indicator of geo-events, we propose a window-based minimum distance classifier based on Bayesian decision theory. The window-based classifier for wireless signal networks has two steps: event detection and event classification. With the event detection, the window-based classifier classifies geo-events on the event occurring regions that are called a classification window. The proposed window-based classification method is evaluated with a water leakage experiment in which the data has been measured in laboratory experiments. In these experiments, the proposed detection and classification method based on wireless signal network can detect and classify subsurface events. PMID:23202191

Removal of uranium (VI) from aqueous systems by nanoscale zero-valent iron particles suspended in carboxy-methyl cellulose

NASA Astrophysics Data System (ADS)

Popescu (Hoştuc), Ioana-Carmen; Filip, Petru; Humelnicu, Doina; Humelnicu, Ionel; Scott, Thomas Bligh; Crane, Richard Andrew

2013-11-01

Carboxy-methyl-cellulose (CMC), a common "delivery vehicle" for the subsurface deployment of iron nanoparticles (INP) has been tested in the current work for the removal of aqueous uranium from synthetic water samples. A comparison of the removal of aqueous uranium from solutions using carboxy-methyl-cellulose with and without iron nanoparticles (CMC-INP and CMC, respectively) was tested over a 48 h reaction period. Analysis of liquid samples using spectrophotometry determined a maximum sorption capacity of uranium, Qmax, of 185.18 mg/g and 322.58 mg/g for CMC and CMC-INP respectively, providing strong evidence of an independent aqueous uranium removal ability exhibited by CMC. The results point out that CMC provides an additional capacity for aqueous uranium removal. Further tests are required to determine whether similar behaviour will be observed for other aqueous contaminant species and if the presence of CMC within a INP slurry inhibits or aids the reactivity, reductive capacity and affinity of INP for aqueous contaminant removal.

PCE DNAPL degradation using ferrous iron solid mixture (ISM).

PubMed

Lee, Hong-Kyun; Do, Si-Hyun; Batchelor, Bill; Jo, Young-Hoon; Kong, Sung-Ho

2009-08-01

Ferrous iron solid mixture (ISM) containing Fe(II), Fe(III), and Cl was synthesized for degradation of tetrachloroethene (PCE) as a dense non-aqueous phase liquid (DNAPL), and an extraction procedure was developed to measure concentrations of PCE in both the aqueous and non-aqueous phases. This procedure included adding methanol along with hexane in order to achieve the high extraction efficiency, particularly when solids were present. When PCE was present as DNAPL, dechlorination of PCE was observed to decrease linearly with respect to the total PCE concentration (aqueous and non-aqueous phases) and the concentration of PCE in the aqueous phase was observed to be approximately constant. In the absence of DNAPL, the rate of PCE degradation was observed to be the first-order with respect to the concentration in the aqueous phase. A kinetic model was developed to describe these observations and it was able to fit experimental data well. Increasing the concentration of Fe(II) in ISM increased the values of rate constants, while increasing the concentration of PCE DNAPL did not affect the value of the rate constant. The reactivity of ISM for PCE dechlorination might be close to that of Friedel's salt, and the accumulation of trichloroethylene (TCE) might imply the lower reactivity of ISM for degradation of TCE or the necessity of large amount of Fe(II) in ISM. TCE (the major chlorinated intermediate), ethene (the major non-chlorinated compound), acetylene and ethane were detected, which implied that both hydrogenolysis and beta-elimination were pathways of PCE DNAPL degradation on ISM.

Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars.

PubMed

Mickol, R L; Kral, T A

2017-12-01

The low pressure at the surface of Mars (average: 6 mbar) is one potentially biocidal factor that any extant life on the planet would need to endure. Near subsurface life, while shielded from ultraviolet radiation, would also be exposed to this low pressure environment, as the atmospheric gas-phase pressure increases very gradually with depth. Few studies have focused on low pressure as inhibitory to the growth or survival of organisms. However, recent work has uncovered a potential constraint to bacterial growth below 25 mbar. The study reported here tested the survivability of four methanogen species (Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis) under low pressure conditions approaching average martian surface pressure (6 mbar - 143 mbar) in an aqueous environment. Each of the four species survived exposure of varying length (3 days - 21 days) at pressures down to 6 mbar. This research is an important stepping-stone to determining if methanogens can actively metabolize/grow under these low pressures. Additionally, the recently discovered recurring slope lineae suggest that liquid water columns may connect the surface to deeper levels in the subsurface. If that is the case, any organism being transported in the water column would encounter the changing pressures during the transport.

Low Pressure Tolerance by Methanogens in an Aqueous Environment: Implications for Subsurface Life on Mars

NASA Astrophysics Data System (ADS)

Mickol, R. L.; Kral, T. A.

2017-12-01

The low pressure at the surface of Mars (average: 6 mbar) is one potentially biocidal factor that any extant life on the planet would need to endure. Near subsurface life, while shielded from ultraviolet radiation, would also be exposed to this low pressure environment, as the atmospheric gas-phase pressure increases very gradually with depth. Few studies have focused on low pressure as inhibitory to the growth or survival of organisms. However, recent work has uncovered a potential constraint to bacterial growth below 25 mbar. The study reported here tested the survivability of four methanogen species ( Methanothermobacter wolfeii, Methanosarcina barkeri, Methanobacterium formicicum, Methanococcus maripaludis) under low pressure conditions approaching average martian surface pressure (6 mbar - 143 mbar) in an aqueous environment. Each of the four species survived exposure of varying length (3 days - 21 days) at pressures down to 6 mbar. This research is an important stepping-stone to determining if methanogens can actively metabolize/grow under these low pressures. Additionally, the recently discovered recurring slope lineae suggest that liquid water columns may connect the surface to deeper levels in the subsurface. If that is the case, any organism being transported in the water column would encounter the changing pressures during the transport.

Optimal Electromagnetic (EM) Geophysical Techniques to Map the Concentration of Subsurface Ice and Adsorbed Water on Mars and the Moon

NASA Astrophysics Data System (ADS)

Stillman, D. E.; Grimm, R. E.

2013-12-01

Water ice is ubiquitous in our Solar System and is a probable target for planetary exploration. Mapping the lateral and vertical concentration of subsurface ice from or near the surface could determine the origin of lunar and martian ice and quantify a much-needed resource for human exploration. Determining subsurface ice concentration on Earth is not trivial and has been attempted previously with electrical resistivity tomography (ERT), ground penetrating radar (GPR), airborne EM (AEM), and nuclear magnetic resonance (NMR). These EM geophysical techniques do not actually detect ice, but rather the absence of unfrozen water. This causes a non-unique interpretation of frozen and dry subsurface sediments. This works well in the arctic because most locations are not dry. However, for planetary exploration, liquid water is exceedingly rare and subsurface mapping must discriminate between an ice-rich and a dry subsurface. Luckily, nature has provided a unique electrical signature of ice: its dielectric relaxation. The dielectric relaxation of ice creates a temperature and frequency dependence of the electrical properties and varies the relative dielectric permittivity from ~3.1 at radar frequencies to >100 at low frequencies. On Mars, sediments smaller than silt size can hold enough adsorbed unfrozen water to complicate the measurement. This is because the presence of absorbed water also creates frequency-dependent electrical properties. The dielectric relaxation of adsorbed water and ice can be separated as they have different shapes and frequency ranges as long as a spectrum spanning the two relaxations is measured. The volume concentration of ice and adsorbed water is a function of the strength of their relaxations. Therefore, we suggest that capacitively-coupled dielectric spectroscopy (a.k.a. spectral induced polarization or complex resistivity) can detect the concentration of both ice and adsorbed water in the subsurface. To prove this concept we have collected dielectric spectroscopy at the Cold Regions Research and Engineering Laboratory (CRREL) permafrost tunnel in Fox, AK. We were able to detect the ice relaxation in the subsurface despite the considerable amount of subsurface unfrozen water due to the presence of montmorillonite clay and much warmer temperatures than Mars or permanently shadowed regions of the Moon. While dielectric spectroscopy can be used to determine ice and adsorbed water content it does not possess the high resolution mapping capability of a GPR. Moreover, GPR cannot detect subsurface ice content in ice-sediment mixtures as evidenced in the interpretation of the Medusae Fossae Formation. Orbital radar surveys show this unit has a low attenuation and a dielectric permittivity near 4. This allows the formation to be interpreted as ice-rich or a dry high-porosity volcanic tuff unit. Therefore, combining GPR and dielectric spectroscopy will enable high-resolution structural and volatile mapping of the subsurface. Furthermore, the addition of neutron spectroscopy would add total hydrogen abundance in the top meter. This could lead to the determination of how much hydrogen resides in ice, adsorbed water, and minerals.

Photointercalating Semiconductor/Solid Electrolyte Junctions for Storage and Chemical Detection. Phase 2.

DTIC Science & Technology

1988-05-31

character- isti, s of single crystal n-HfS 2 in liquid non-aqueous electrolyte (acetonitrile containing O.1M tetrabutylammonium hexafluorophosphate ...INC There are several incentives for the direct detection of SO2 under ambient conditions. These include potential leakage from pressurized lithium /SO

Potent chemopreventive/antioxidant activity detected in common spices of the Apiaceae family

PubMed Central

Jeyabalan, Jeyaprakash; Aqil, Farrukh; Soper, Lisa; Schultz, David J.; Gupta, Ramesh C.

2015-01-01

Spices are used worldwide, particularly, in the Asian and Middle-Eastern countries and considered protective against degenerative diseases, including cancer. Here, we report the efficacy of aqueous and non-aqueous extracts of eleven Apiaceae spices for free radical-scavenging activity and to inhibit cytochrome P450s in two separate reactions involving: i) 4-hydroxy-17β-estradiol (4E2), DNA and CuCl2 and ii) 17β-estradiol, rat liver microsomes, co-factors, DNA and CuCl2. Oxidative DNA adducts resulting from redox cycling of 4E2 were analyzed by 32P-postlabeling. Aqueous (5 mg/ml) and non-aqueous extracts (6 mg/ml) substantially inhibited (83% – 98%) formation of DNA adducts in the microsomal reaction. However, in non-microsomal reaction, only aqueous extracts showed the inhibitory activity (83% – 96%). Adduct inhibition was also observed at 5-fold lower concentrations of aqueous extracts of cumin (60%) and caraway (90%), and 10-fold lower concentrations of carrot seeds (76%) and ajowan (90%). These results suggests the presence of two groups of phytochemicals - polar compounds that have free radical-scavenging activity, and lipophilic compounds that selectively inhibit P450 activity associated with estrogen metabolism. Because most of these Apiaceae spices are used widely with no known toxicity, the phytochemicals from the Apiaceae spices used in foods may be potentially protective against estrogen-mediated breast cancer. PMID:26381237

Effective Detection of Sub-Surface Archeological Features from Laser Scanning Point Clouds and Imagery Data

NASA Astrophysics Data System (ADS)

Fryskowska, A.; Kedzierski, M.; Walczykowski, P.; Wierzbicki, D.; Delis, P.; Lada, A.

2017-08-01

The archaeological heritage is non-renewable, and any invasive research or other actions leading to the intervention of mechanical or chemical into the ground lead to the destruction of the archaeological site in whole or in part. For this reason, modern archeology is looking for alternative methods of non-destructive and non-invasive methods of new objects identification. The concept of aerial archeology is relation between the presence of the archaeological site in the particular localization, and the phenomena that in the same place can be observed on the terrain surface form airborne platform. One of the most appreciated, moreover, extremely precise, methods of such measurements is airborne laser scanning. In research airborne laser scanning point cloud with a density of 5 points/sq. m was used. Additionally unmanned aerial vehicle imagery data was acquired. Test area is located in central Europe. The preliminary verification of potentially microstructures localization was the creation of digital terrain and surface models. These models gave an information about the differences in elevation, as well as regular shapes and sizes that can be related to the former settlement/sub-surface feature. The paper presents the results of the detection of potentially sub-surface microstructure fields in the forestry area.

Subsurface water and clay mineral formation during the early history of Mars.

PubMed

Ehlmann, Bethany L; Mustard, John F; Murchie, Scott L; Bibring, Jean-Pierre; Meunier, Alain; Fraeman, Abigail A; Langevin, Yves

2011-11-02

Clay minerals, recently discovered to be widespread in Mars's Noachian terrains, indicate long-duration interaction between water and rock over 3.7 billion years ago. Analysis of how they formed should indicate what environmental conditions prevailed on early Mars. If clays formed near the surface by weathering, as is common on Earth, their presence would indicate past surface conditions warmer and wetter than at present. However, available data instead indicate substantial Martian clay formation by hydrothermal groundwater circulation and a Noachian rock record dominated by evidence of subsurface waters. Cold, arid conditions with only transient surface water may have characterized Mars's surface for over 4 billion years, since the early-Noachian period, and the longest-duration aqueous, potentially habitable environments may have been in the subsurface.

Effective diffusion coefficients of DNAPL waste components in saturated low permeability soil materials

NASA Astrophysics Data System (ADS)

Ayral-Cinar, Derya; Demond, Avery H.

2017-12-01

Diffusion is regarded as the dominant transport mechanism into and out of low permeable subsurface lenses and layers in the subsurface. But, some reports of mass storage in such zones are higher than what might be attributable to diffusion, based on estimated diffusion coefficients. Despite the importance of diffusion to efforts to estimate the quantity of residual contamination in the subsurface, relatively few studies present measured diffusion coefficients of organic solutes in saturated low permeability soils. This study reports the diffusion coefficients of a trichloroethylene (TCE), and an anionic surfactant, Aerosol OT (AOT), in water-saturated silt and a silt-montmorillonite (25:75) mixture, obtained using steady-state experiments. The relative diffusivity ranged from 0.11 to 0.17 for all three compounds for the silt and the silt-clay mixture that was allowed to expand. In the case in which the swelling was constrained, the relative diffusivity was about 0.07. In addition, the relative diffusivity of 13C-labeled TCE through a water saturated silt-clay mixture that had contacted a field dense non-aqueous phase liquid (DNAPL) for 18 months was measured and equaled 0.001. These experimental results were compared with the estimates generated using common correlations, and it was found that, in all cases, the measured diffusion coefficients were significantly lower than the estimated. Thus, the discrepancy between mass accumulations observed in the field and the mass storage that can attributable to diffusion may be greater than previously believed.

Influence of bedrock topography on the runoff generation under use of ERT data

NASA Astrophysics Data System (ADS)

Kiese, Nina; Loritz, Ralf; Allroggen, Niklas; Zehe, Erwin

2017-04-01

Subsurface topography has been identified to play a major role for the runoff generation in different hydrological landscapes. Sinks and ridges in the bedrock can control how water is stored and transported to the stream. Detecting the subsurface structure is difficult and laborious and frequently done by auger measurements. Recently, the geophysical imaging of the subsurface by Electrical Resistivity Tomography (ERT) gained much interest in the field of hydrology, as it is a non-invasive method to collect information on the subsurface characteristics and particularly bedrock topography. As it is impossible to characterize the subsurface of an entire hydrological landscape using ERT, it is of key interest to identify the bedrock characteristics which dominate runoff generation to adapt and optimize the sampling design to the question of interest. For this study, we used 2D ERT images and auger measurements, collected on different sites in the Attert basin in Luxembourg, to characterize bedrock topography using geostatistics and shed light on those aspects which dominate runoff generation. Based on ERT images, we generated stochastic bedrock topographies and implemented them in a physically-based 2D hillslope model. With this approach, we were able to test the influence of different subsurface structures on the runoff generation. Our results highlight that ERT images can be useful for hydrological modelling. Especially the connection from the hillslope to the stream could be identified as important feature in the subsurface for the runoff generation whereas the microtopography of the bedrock seemed to be less relevant.

Chemical and microbiological water quality of subsurface agricultural drains during a field trial of liquid dairy manure effluent application rate and varying tillage practices, Upper Tiffin Watershed, southeastern Michigan

USGS Publications Warehouse

Haack, Sheridan Kidd; Duris, Joseph W.

2008-01-01

A field trial was done in the Upper Tiffin River Watershed, in southeastern Michigan, to determine the influence of liquid dairy manure effluent (LDME) management practices on the quality of agricultural subsurface-drain water. Samples from subsurface drains were analyzed for nutrients, fecal-coliform and Escherichia coli (E. coli) bacteria, antibiotics, chemicals typically detected in wastewater, and the occurrence of genes indicating the presence of shiga-toxin-producing E. coli, or of bovine-specific Bacteroidetes bacteria. Samples were collected from November 2, 2006, to March 20, 2007, from eight subsurface drains under field plots that received no LDME and no tillage (controls) or received 4,000 or 8,000 gallons per acre (gal/acre) of LDME and either no tillage or two different types of tillage. The two types of tillage tested were (1) ground-driven, rotary, subsurface cultivation and (2) rolling-tine aeration. Samples were collected before LDME application and at 4 hours, and 1, 2, 6, 7, and 14 days post-application. Nutrient concentrations were high in subsurface-drain water throughout the field-trial period and could not be attributed to the field-trial LDME application. Of the 59 drain-water samples, including those collected before LDME application and control samples for each date, 56 had concentrations greater than the U.S. Environmental Protection Agency (USEPA), Ecoregion VI recommended surface-water criterion for total phosphorus, and all samples had concentrations greater than the recommended total nitrogen criterion. Nitrate + nitrite nitrogen concentration exceeded 20 milligrams per liter for every sample and contributed most to the total nitrogen concentrations. Substantial increases in drain-water concentrations of organic and ammonia nitrogen and total phosphorus were found for all treatments, including controls, at 14 days post-application after 0.84 inch of rainfall over 2 days. E. coli concentrations exceeded the USEPA recreational-water-quality single-sample criterion of 235 colony forming units per 100 milliliters in only 3 of 56 samples. Of these three samples, two were collected within 1 day post-LDME application from the treatment receiving 8,000 gal/acre LDME with no tillage (NT8000). The third sample was from the rolling-tine aerator treatment with 4,000 gal/acre LDME application rate after the first significant rainfall. Two wastewater chemicals and two bacterial genes (eaeA and stx1) detected in the LDME, but absent in field blank or pre-application samples, were detected in the 4-hour or 1-day postapplication NT8000 samples. No LDME-associated chemicals were detected in later samples from the NT8000 treatment, and none were detected in samples from other treatments after the first significant rainfall. Results of this field trial were somewhat equivocal with respect to the influence of LDME concentration and tillage practices on subsurface-drain water quality, both immediately after LDME application and in the longer term, after significant rainfall. Interpretation of study findings is limited by the fact that treatments were not replicated, and flow rate or discharge from the subsurface drains was not measured. Nevertheless, study results provide useful information about nutrient and bacteria concentrations in subsurface drains during the non-growing season. In addition, study results demonstrate some potential for the use of chemical and microbiological indicators of LDME transport to subsurface drains.

Cyclodextrin-enhanced solubilization of organic contaminants with implications for aquifer remediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCray, J.E.; Boving, T.B.; Brusseau, M.L.

2000-12-31

Reagents that enhance the aqueous solubility of nonaqueous phase organic liquid (NAPL) contaminants are under investigation for use in enhanced subsurface remediation technologies. Cyclodextrin, a glucose-based molecule, is such a reagent. In this paper, laboratory experiments and numerical model simulations are used to evaluate and understand the potential remediation performance of cyclodextrin. Physical properties of cyclodextrin solutions such as density, viscosity, and NAPL-aqueous interfacial tension are measured. Their analysis indicates that no serious obstacles exist related to fluid properties that would prevent the use of cyclodextrin solutions for subsurface NAPL remediation. Cyclodextrin-enhanced solubilization for a large suite of typical groundmore » water contaminants is measured in the laboratory, and the results are related to the physiochemical properties of the organic compounds. The most-hydrophobic contaminants experience a larger relative solubility enhancement than the less-hydrophobic contaminants but have lower aqueous-phase apparent solubilities. Numerical model simulations of enhanced-solubilization flushing of NAPL-contaminated soil demonstrate that the more-hydrophilic compounds exhibit the greatest mass-removal relates due to their greater apparent solubilities, and thus are initially more effectively removed from soil by enhanced-solubilization-flushing reagents. However, the relatively more hydrophobic contaminants exhibit a greater improvement in contaminant mass-removal (compared with water flushing) than that exhibited for the relatively hydrophilic contaminants.« less

Uranium transport in a crushed granodiorite: Experiments and reactive transport modeling

DOE PAGES

Dittrich, T. M.; Reimus, P. W.

2015-02-12

The primary objective of this study was to develop and demonstrate an experimental method to refine and better parameterize process models for reactive contaminant transport in aqueous subsurface environments and to reduce conservatism in such models without attempting to fully describe the geochemical system.

Detection of the actinides and cesium from environmental samples

NASA Astrophysics Data System (ADS)

Snow, Mathew Spencer

Detection of the actinides and cesium in the environment is important for a variety of applications ranging from environmental remediation to safeguards and nuclear forensics. The utilization of multiple different elemental concentrations and isotopic ratios together can significantly improve the ability to attribute contamination to a unique source term and/or generation process; however, the utilization of multiple elemental "signatures" together from environmental samples requires knowledge of the impact of chemical fractionation for various elements under a variety of environmental conditions (including predominantly aqueous versus arid conditions). The research reported in this dissertation focuses on three major areas: 1. Improving the understanding of actinide-mineral interactions at ultra-low concentrations. Chapter 2 reports a batch sorption and modeling study of Np(V) sorption to the mineral goethite from attomolar to micromolar concentrations. 2. Improving the detection capabilities for Thermal Ionization Mass Spectrometry (TIMS) analyses of ultra-trace cesium from environmental samples. Chapter 4 reports a new method which significantly improves the chemical yields, purification, sample processing time, and ultimately, the detection limits for TIMS analyses of femtogram quantities of cesium from a variety of environmental sample matrices. 3. Demonstrating how actinide and cesium concentrations and isotopic ratios from environmental samples can be utilized together to determine a wealth of information including environmental transport mechanisms (e.g. aqueous versus arid transport) and information on the processes which generated the original material. Chapters1, 3 and 5 demonstrate these principles using Pu, Am, Np, and Cs concentrations and isotopic ratios from contaminated soils taken near the Subsurface Disposal Area (SDA) of Idaho National Laboratory (INL) (a low level radioactive waste disposal site in southeastern Idaho).

Mars Sulfur: A Review of Landed Mission Data (Invited)

NASA Astrophysics Data System (ADS)

Sutter, B.; Ming, D. W.; Niles, P. B.

2013-12-01

Sulfur (S) has been detected (1.0 - 36 wt. % SO3) in martian surface materials at the Viking, Pathfinder, Mars Exploration Rovers (MER), Phoenix, and Mars Science Laboratory (MSL) landing sites. The accumulation of S at these landing sites is attributed to the hyperarid martian climate that inhibits dissolution and leaching of surface S into the subsurface. The S cycle involving sources, sinks, and the processes involved in redistributing S after initial deposition are not well constrained. This work reviews the state of knowledge of S as derived from landed missions. Results suggest that aqueous processes have been involved in the S cycling suggesting that conditions may have been favorable microbiology. Chemical data and the apparent oxidizing condition of the soil suggest that the Viking and Pathfinder soils consist of Mg-sulfate and possible Fe-sulfate. Sulfur-rich soils (up to 36 wt. % SO3) in Gusev crater examined by MER Spirit consist of mixed Fe3+)-, Mg- , and Ca-sulfates. Meridiani Plenum explored by MER Opportunity is dominated by outcrops of mixed Fe-, Mg- and Ca-sulfate while rocks stratigraphically below this at Endeavor Crater contain veins composed of calcium sulfate. Soil solutions evaluated at the Phoenix Landing site were consistent with the presence of Mg-sulfate, while the thermal and evolved gas data collected from this site suggested that Ca-sulfate could also be present. X-ray diffraction analysis of the Rocknest sand shadow in Gale Crater detected anhydrite (CaSO4)(~1 wt.%) The source of S on the martian surface may be derived from S-bearing volcanic aerosols and/or from subsurface hydrothermal fluids that have interacted with sulfide minerals in the crust. For example, volcanic derived S aerosols in water or ice have been proposed to alter basaltic material where acidic fluids evaporated or ice sublimed leaving behind the large-scale Meridiani sulfate outcrops. On the other hand, local small-scale hydrothermal processes may be responsible for locally concentrated S in the Paso Robles soils in the Columbia Hills encountered by Spirit. Subsequent to deposition, redistribution of S by aqueous or eolian processes is possible. Physical erosion of S deposits detected elsewhere on Mars followed by eolian redistribution of S bearing dust could contribute to soil S. Downward water flow has been proposed to have leached sulfates in select Gusev soils and may be involved in sulfate redistribution in the Meridiani deposits. Sources of downward water flow could be caused by percolating snow melt that occurs during periods of high obliquity. Subsequent to deposition, groundwater interactions are also proposed as a mechanism for the redistributed the Meridiani sulfates. The evaluation of martian of the S cycle should shed light on the past martian climate and indicate the types of aqueous geochemical conditions that were encountered by potential microbiology. Aqueous processes involved the S cycle appear to span a wide pH range from acidic (Fe-sulfates) to more neutral (Fe-sulfate limiting). This range of pH suggests that martian microbiology, if ever present, was diverse and consisted of species that thrived in low pH solutions (e.g., acidophilles) along with species that thrived in more neutral pH solutions.

High resolution subsurface imaging using resonance-enhanced detection in 2nd-harmonic KPFM.

PubMed

Cadena, Maria Jose; Reifenberger, Ronald G; Raman, Arvind

2018-06-28

Second harmonic Kelvin probe force microscopy is a robust mechanism for subsurface imaging at the nanoscale. Here we exploit resonance-enhanced detection as a way to boost the subsurface contrast with higher force sensitivity using lower bias voltages, in comparison to the traditional off-resonance case. In this mode, the second harmonic signal of the electrostatic force is acquired at one of the eigenmode frequencies of the microcantilever. As a result, high-resolution subsurface images are obtained in a variety of nanocomposites. To further understand the subsurface imaging detection upon electrostatic forces, we use a finite element model that approximates the geometry of the probe and sample. This allows the investigation of the contrast mechanism, the depth sensitivity and lateral resolution depending on tip-sample properties. © 2018 IOP Publishing Ltd.

A Protocol for Electrochemical Evaluations and State of Charge Diagnostics of a Symmetric Organic Redox Flow Battery.

PubMed

Duan, Wentao; Vemuri, Rama S; Hu, Dehong; Yang, Zheng; Wei, Xiaoliang

2017-02-13

Redox flow batteries have been considered as one of the most promising stationary energy storage solutions for improving the reliability of the power grid and deployment of renewable energy technologies. Among the many flow battery chemistries, non-aqueous flow batteries have the potential to achieve high energy density because of the broad voltage windows of non-aqueous electrolytes. However, significant technical hurdles exist currently limiting non-aqueous flow batteries to demonstrate their full potential, such as low redox concentrations, low operating currents, under-explored battery status monitoring, etc. In an attempt to address these limitations, we recently reported a non-aqueous flow battery based on a highly soluble, redox-active organic nitronyl nitroxide radical compound, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO). This redox material exhibits an ambipolar electrochemical property, and therefore can serve as both anolyte and catholyte redox materials to form a symmetric flow battery chemistry. Moreover, we demonstrated that Fourier transform infrared (FTIR) spectroscopy could measure the PTIO concentrations during the PTIO flow battery cycling and offer reasonably accurate detection of the battery state of charge (SOC), as cross-validated by electron spin resonance (ESR) measurements. Herein we present a video protocol for the electrochemical evaluation and SOC diagnosis of the PTIO symmetric flow battery. With a detailed description, we experimentally demonstrated the route to achieve such purposes. This protocol aims to spark more interests and insights on the safety and reliability in the field of non-aqueous redox flow batteries.

Detection of Gray Crystalline Hematite in the Aureum and Iani Chaos Layered Terrains

NASA Astrophysics Data System (ADS)

Glotch, T. D.; Rogers, D.; Christensen, P. R.

2005-12-01

Using the TES and THEMIS datasets, small hematite-rich deposits have been discovered in Aureum and Iani Chaos. The newly discovered hematite-rich deposits share several similarities with the deposit in Aram Chaos [1], including the occurrence of hematite in a friable layered unit, and the presence of a light-toned caprock. The presence of these units over a distance of several hundred kilometers in the equatorial latitudes of Mars may point to a preferred global mechanism for hematite formation. However, it is unclear how, if at all, these units are related to the hematite- and sulfate-rich unit in Meridiani Planum, which is substantially larger and older (by as much as 1 Ga) than the layered units seen in the equatorial chaotic terrains. Though the caprock units in Aram Chaos and Aureum Chaos are similar, the corresponding unit in Iani Chaos is morphologically different, exhibiting less of a cliff-forming erosional pattern. The hematite-rich units in Aram and Aureum Chaos lie stratigraphically below the light-toned caprock units. In Iani Chaos, the hematite deposit is coincident with the light-toned unit. Data returned from the Mars Express OMEGA instrument have shown the presence of hydrated sulfates in the hematite-rich units associated with Aram and Iani Chaos, although to date, no sulfate detection has been reported in Aureum Chaos [2]. The sequence of caprock and hematite units in Aram, Aureum, and Iani Chaos probably did not form coincidentally as part of an extensive regional layer, but instead formed by similar, but not identical, processes in their respective chaotic terrains. The presence of these units in chaotic terrains, which have been hypothesized to form by subsidence after the release of subsurface water, indicate that these units may have been deposited in an aqueous environment. By analogy to Meridiani Planum, later subsurface aqueous activity in the region of the chaotic terrains may have provided the necessary diagenetic conditions for the formation of hematite within the layered units. [1] Glotch and Christensen, J. Geophys. Res., in press. [2] Gendrin et al., 2005, Science, 307 p. 1587-1590

Development of a multi-residue method for the determination of human and veterinary pharmaceuticals and some of their metabolites in aqueous environmental matrices by SPE-UHPLC-MS/MS.

PubMed

Paíga, P; Santos, L H M L M; Delerue-Matos, C

2017-02-20

The aim of the present work was to develop and validate a multi-residue method for the analysis of 33 human and veterinary pharmaceuticals (non-steroidal anti-inflammatory drugs (NSAIDs)/analgesics, antibiotics and psychiatric drugs), including some of their metabolites, in several aqueous environmental matrices: drinking water, surface water and wastewaters. The method is based on solid phase extraction (SPE) followed by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and it was validated for different aqueous matrices, namely bottled water, tap water, seawater, river water and wastewaters, showing recoveries between 50% and 112% for the majority of the target analytes. The developed analytical methodology allowed method detection limits in the low nanograms per liter level. Method intra- and inter-day precision was under 8% and 11%, respectively, expressed as relative standard deviation. The developed method was applied to the analysis of drinking water (bottled and tap water), surface waters (seawater and river water) and wastewaters (wastewater treatment plant (WWTP) influent and effluent). Due to the selectivity and sensitivity of the optimized method, it was possible to detect pharmaceuticals in all the aqueous environmental matrices considered, including in bottled water at concentrations up to 31ngL -1 (salicylic acid). In general, non-steroidal anti-inflammatory drugs/analgesics was the therapeutic group most frequently detected, with the highest concentrations found in wastewaters (acetaminophen and the metabolite carboxyibuprofen at levels up to 615 and 120μgL -1 , respectively). Copyright © 2016 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, Sean W., E-mail: sean.king@intel.com; Davis, Robert F.; Carter, Richard J.

The desorption kinetics of molecular hydrogen (H{sub 2}) from silicon (001) surfaces exposed to aqueous hydrogen fluoride and remote hydrogen plasmas were examined using temperature programmed desorption. Multiple H{sub 2} desorption states were observed and attributed to surface monohydride (SiH), di/trihydride (SiH{sub 2/3}), and hydroxide (SiOH) species, subsurface hydrogen trapped at defects, and hydrogen evolved during the desorption of surface oxides. The observed surface hydride species were dependent on the surface temperature during hydrogen plasma exposure with mono, di, and trihydride species being observed after low temperature exposure (150 °C), while predominantly monohydride species were observed after higher temperature exposure (450 °C).more » The ratio of surface versus subsurface H{sub 2} desorption was also found to be dependent on the substrate temperature with 150 °C remote hydrogen plasma exposure generally leading to more H{sub 2} evolved from subsurface states and 450 °C exposure leading to more H{sub 2} desorption from surface SiH{sub x} species. Additional surface desorption states were observed, which were attributed to H{sub 2} desorption from Si (111) facets formed as a result of surface etching by the remote hydrogen plasma or aqueous hydrogen fluoride treatment. The kinetics of surface H{sub 2} desorption were found to be in excellent agreement with prior investigations of silicon surfaces exposed to thermally generated atomic hydrogen.« less

Non-aqueous electrolytes for isotachophoresis of weak bases and its application to the comprehensive preconcentration of the 20 proteinogenic amino acids in column-coupling ITP/CE-MS.

PubMed

Kler, Pablo A; Huhn, Carolin

2014-11-01

Isotachophoresis (ITP) has long been used alone but also as a preconcentration technique for capillary electrophoresis (CE). Unfortunately, up to now, its application is restricted to relatively strong acids and bases as either the degree of (de)protonation is too low or the water dissociation is too high, evoking zone electrophoresis. With the comprehensive ITP analysis of all 20 proteinogenic amino acids as model analytes, we, here, show that non-aqueous ITP using dimethylsulfoxide as a solvent solves this ITP shortcoming. Dimethylsulfoxide changes the pH regime of analytes and electrolytes but, more importantly, strongly reduces the proton mobility by prohibiting hydrogen bonds and thus, the so-called Zundel-Eigen-Zundel electrical conduction mechanism of flipping hydrogen bonds. The effects are demonstrated in an electrolyte system with taurine or H(+) as terminator, and imidazole as leader together with strong acids such as oxalic and even trifluoroacetic acid as counterions, both impossible to use in aqueous solution. Mass spectrometric as well as capacitively coupled contactless conductivity detection (C(4)D) are used to follow the ITP processes. To demonstrate the preconcentration capabilities of ITP in a two-dimensional set-up, we, here, also demonstrate that our non-aqueous ITP method can be combined with capillary electrophoresis-mass spectrometry in a column-coupling system using a hybrid approach of capillaries coupled to a microfluidic interface. For this, C(4)D was optimized for on-chip detection with the electrodes aligned on top of a thin glass lid of the microfluidic chip.

Aram Chaos: A Long Lived Subsurface Aqueous Environment with Strong Water Resource Potential for Human Missions on Mars

NASA Astrophysics Data System (ADS)

Sibille, L.; Mueller, R. P.; Niles, P. B.; Glotch, T.; Archer, P. D.; Bell, M. S.

2015-10-01

Aram Chaos is a 280-km-wide near-circular structure near the outflow channel Ares Vallis and Aureum Chaos. It is a compelling landing site for human explorers featuring multiple science ROIs with a compelling resource ROI with polyhydrated sulfates.

Treatment of Aqueous Film-Forming Foam by Heat-Activated Persulfate Under Conditions Representative of In Situ Chemical Oxidation

PubMed Central

2017-01-01

Poly- and perfluoroalkyl substances (PFASs) have been detected in an increasing number of water supplies. In many instances, the contamination is associated with the use of PFAS-containing aqueous film-forming foams (AFFF) in firefighting activities. To investigate the potential for remediating AFFF contamination in groundwater with heat-activated persulfate, PFAS oxidation and the generation of transformation products was evaluated under well-controlled conditions. Fluorotelomer- and perfluoroalkyl sulfonamide-based polyfluorinated compounds were transformed to perfluorinated carboxylic acids, which underwent further degradation under acidic conditions produced after persulfate decomposed. The presence of aquifer sediments decreased the efficiency of the remedial process but did not alter the transformation pathways. At high concentrations, the presence of organic solvents, such as those present in AFFF formulations, inhibited transformation of a representative perfluorinated compound, perfluorooctanoic acid. Heat-activated persulfate did not transform perfluorooctanesulfonic acid or perfluorohexanesulfonic acid under any conditions. Despite challenges associated with the creation of acidic conditions in the subsurface, the potential for generation of undesirable transformation products, and the release of toxic metals, heat-activated persulfate may be a useful in situ treatment for sites contaminated with polyfluoroalkyl substances and perfluorocarboxylic acids. PMID:29164864

Object detection with a multistatic array using singular value decomposition

DOEpatents

Hallquist, Aaron T.; Chambers, David H.

2014-07-01

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across a surface and that travels down the surface. The detection system converts the return signals from a time domain to a frequency domain, resulting in frequency return signals. The detection system then performs a singular value decomposition for each frequency to identify singular values for each frequency. The detection system then detects the presence of a subsurface object based on a comparison of the identified singular values to expected singular values when no subsurface object is present.

Developments in Titrimetry.

ERIC Educational Resources Information Center

Parry-Jones, R.

1980-01-01

Described are some new uses and procedures of titration procedures. Topics included are titration in non-aqueous solvents, thermometric titration and catalytic methods for end-point detection, titration finish in organic elemental analysis, and sub-micro analysis and automatic titration procedures. (CS)

Self-potential and Complex Conductivity Monitoring of In Situ Hydrocarbon Remediation in Microbial Fuel Cell

NASA Astrophysics Data System (ADS)

Zhang, C.; Revil, A.; Ren, Z.; Karaoulis, M.; Mendonca, C. A.

2013-12-01

Petroleum hydrocarbon contamination of soil and groundwater in both non-aqueous phase liquid and dissolved forms generated from spills and leaks is a wide spread environmental issue. Traditional cleanup of hydrocarbon contamination in soils and ground water using physical, chemical, and biological remedial techniques is often expensive and ineffective. Recent studies show that the microbial fuel cell (MFC) can simultaneously enhance biodegradation of hydrocarbons in soil and groundwater and yield electricity. Non-invasive geophysical techniques such as self-potential (SP) and complex conductivity (induced polarization) have shown the potential to detect and characterize the nature of electron transport mechanism of in situ bioremediation of organic contamination plumes. In this study, we deployed both SP and complex conductivity in lab scale MFCs to monitor time-laps geophysical response of degradation of hydrocarbons by MFC. Two different sizes of MFC reactors were used in this study (DI=15 cm cylinder reactor and 94.5cm x 43.5 cm rectangle reactor), and the initial hydrocarbon concentration is 15 g diesel/kg soil. SP and complex conductivity measurements were measured using non-polarizing Ag/AgCl electrodes. Sensitivity study was also performed using COMSOL Multiphysics to test different electrode configurations. The SP measurements showed stronger anomalies adjacent to the MFC than locations afar, and both real and imaginary parts of complex conductivity are greater in areas close to MFC than areas further away and control samples without MFC. The joint use of SP and complex conductivity could in situ evaluate the dynamic changes of electrochemical parameters during this bioremediation process at spatiotemporal scales unachievable with traditional sampling methods. The joint inversion of these two methods to evaluate the efficiency of MFC enhanced hydrocarbon remediation in the subsurface.

Fate and Transport of Nanoparticles in Porous Media: A Numerical Study

NASA Astrophysics Data System (ADS)

Taghavy, Amir

Understanding the transport characteristics of NPs in natural soil systems is essential to revealing their potential impact on the food chain and groundwater. In addition, many nanotechnology-based remedial measures require effective transport of NPs through soil, which necessitates accurate understanding of their transport and retention behavior. Based upon the conceptual knowledge of environmental behavior of NPs, mathematical models can be developed to represent the coupling of processes that govern the fate of NPs in subsurface, serving as effective tools for risk assessment and/or design of remedial strategies. This work presents an innovative hybrid Eulerian-Lagrangian modeling technique for simulating the simultaneous reactive transport of nanoparticles (NPs) and dissolved constituents in porous media. Governing mechanisms considered in the conceptual model include particle-soil grain, particle-particle, particle-dissolved constituents, and particle- oil/water interface interactions. The main advantage of this technique, compared to conventional Eulerian models, lies in its ability to address non-uniformity in physicochemical particle characteristics. The developed numerical simulator was applied to investigate the fate and transport of NPs in a number of practical problems relevant to the subsurface environment. These problems included: (1) reductive dechlorination of chlorinated solvents by zero-valent iron nanoparticles (nZVI) in dense non-aqueous phase liquid (DNAPL) source zones; (2) reactive transport of dissolving silver nanoparticles (nAg) and the dissolved silver ions; (3) particle-particle interactions and their effects on the particle-soil grain interactions; and (4) influence of particle-oil/water interface interactions on NP transport in porous media.

High frequency electromagnetic impedance measurements for characterization, monitoring and verification efforts. 1998 annual progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, K.H.; Pellerin, L.; Becker, A.

1998-06-01

'Non-invasive, high-resolution imaging of the shallow subsurface is needed for delineation of buried waste, detection of unexploded ordinance, verification and monitoring of containment structures, and other environmental applications. Electromagnetic measurements at frequencies between 1 and 100 MHz are important for such applications, because the induction number of many targets is small due, and the ability to determine the dielectric permittivity in addition to electrical conductivity of the subsurface is possible. Earlier workers were successful in developing systems for detecting anomalous areas, but no quantifiable information was accurately determined. For high resolution imaging, accurate measurements are necessary so the field datamore » can be mapped into the space of the subsurface parameters. The authors are developing a non-invasive method for accurately imaging the electrical conductivity and dielectric permittivity of the shallow subsurface using the plane wave impedance approach, known as the magnetotelluric (MT) method at low frequencies. Electric and magnetic sensors are being tested in a known area against theoretical predictions, thereby insuring that the data collected with the high-frequency impedance (HFI) system will support high-resolution, multi-dimensional imaging techniques. The summary of the work to date is divided into three sections: equipment procurement, instrumentation, and theoretical developments. For most earth materials, the frequency range from 1 to 100 MHz encompasses a very difficult transition zone between the wave propagation of displacement currents and the diffusive behavior of conduction currents. Test equipment, such as signal generators and amplifiers, does not cover the entire range except at great expense. Hence the authors have divided the range of investigation into three sub-ranges: 1--10 MHz, 10--30 MHz, and 30--100 MHz. Results to date are in the lowest frequency range of 1--10 MHz. Even though conduction currents dominate in this range, as in traditional electromagnetic exploration methods, little work has been done by the geophysical community above 500 kHz.'« less

Buried object detection in GPR images

DOEpatents

Paglieroni, David W; Chambers, David H; Bond, Steven W; Beer, W. Reginald

2014-04-29

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

Earth analysis methods, subsurface feature detection methods, earth analysis devices, and articles of manufacture

DOEpatents

West, Phillip B [Idaho Falls, ID; Novascone, Stephen R [Idaho Falls, ID; Wright, Jerry P [Idaho Falls, ID

2012-05-29

Earth analysis methods, subsurface feature detection methods, earth analysis devices, and articles of manufacture are described. According to one embodiment, an earth analysis method includes engaging a device with the earth, analyzing the earth in a single substantially lineal direction using the device during the engaging, and providing information regarding a subsurface feature of the earth using the analysis.

Earth analysis methods, subsurface feature detection methods, earth analysis devices, and articles of manufacture

DOEpatents

West, Phillip B [Idaho Falls, ID; Novascone, Stephen R [Idaho Falls, ID; Wright, Jerry P [Idaho Falls, ID

2011-09-27

Earth analysis methods, subsurface feature detection methods, earth analysis devices, and articles of manufacture are described. According to one embodiment, an earth analysis method includes engaging a device with the earth, analyzing the earth in a single substantially lineal direction using the device during the engaging, and providing information regarding a subsurface feature of the earth using the analysis.

Spot restoration for GPR image post-processing

DOEpatents

Paglieroni, David W; Beer, N. Reginald

2014-05-20

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

Effective diffusion coefficients of DNAPL waste components in saturated low permeability soil materials.

PubMed

Ayral-Cinar, Derya; Demond, Avery H

2017-12-01

Diffusion is regarded as the dominant transport mechanism into and out of low permeable subsurface lenses and layers in the subsurface. But, some reports of mass storage in such zones are higher than what might be attributable to diffusion, based on estimated diffusion coefficients. Despite the importance of diffusion to efforts to estimate the quantity of residual contamination in the subsurface, relatively few studies present measured diffusion coefficients of organic solutes in saturated low permeability soils. This study reports the diffusion coefficients of a trichloroethylene (TCE), and an anionic surfactant, Aerosol OT (AOT), in water-saturated silt and a silt-montmorillonite (25:75) mixture, obtained using steady-state experiments. The relative diffusivity ranged from 0.11 to 0.17 for all three compounds for the silt and the silt-clay mixture that was allowed to expand. In the case in which the swelling was constrained, the relative diffusivity was about 0.07. In addition, the relative diffusivity of 13 C-labeled TCE through a water saturated silt-clay mixture that had contacted a field dense non-aqueous phase liquid (DNAPL) for 18months was measured and equaled 0.001. These experimental results were compared with the estimates generated using common correlations, and it was found that, in all cases, the measured diffusion coefficients were significantly lower than the estimated. Thus, the discrepancy between mass accumulations observed in the field and the mass storage that can attributable to diffusion may be greater than previously believed. Copyright © 2017. Published by Elsevier B.V.

Fluorescence tomography characterization for sub-surface imaging with protoporphyrin IX

PubMed Central

Kepshire, Dax; Davis, Scott C.; Dehghani, Hamid; Paulsen, Keith D.; Pogue, Brian W.

2009-01-01

Optical imaging of fluorescent objects embedded in a tissue simulating medium was characterized using non-contact based approaches to fluorescence remittance imaging (FRI) and sub-surface fluorescence diffuse optical tomography (FDOT). Using Protoporphyrin IX as a fluorescent agent, experiments were performed on tissue phantoms comprised of typical in-vivo tumor to normal tissue contrast ratios, ranging from 3.5:1 up to 10:1. It was found that tomographic imaging was able to recover interior inclusions with high contrast relative to the background; however, simple planar fluorescence imaging provided a superior contrast to noise ratio. Overall, FRI performed optimally when the object was located on or close to the surface and, perhaps most importantly, FDOT was able to recover specific depth information about the location of embedded regions. The results indicate that an optimal system for localizing embedded fluorescent regions should combine fluorescence reflectance imaging for high sensitivity and sub-surface tomography for depth detection, thereby allowing more accurate localization in all three directions within the tissue. PMID:18545571

Real-time system for imaging and object detection with a multistatic GPR array

DOEpatents

Paglieroni, David W; Beer, N Reginald; Bond, Steven W; Top, Philip L; Chambers, David H; Mast, Jeffrey E; Donetti, John G; Mason, Blake C; Jones, Steven M

2014-10-07

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

Detection of Scopolamine Hydrobromide via Surface-enhanced Raman Spectroscopy.

PubMed

Bao, Lin; Sha, Xuan-Yu; Zhao, Hang; Han, Si-Qin-Gao-Wa; Hasi, Wu-Li-Ji

2017-01-01

Surface-enhanced Raman spectroscopy (SERS) was used to measure scopolamine hydrobromide. First, the Raman characteristic peaks of scopolamine hydrobromide were assigned, and the characteristic peaks were determined. The optimal aggregation agent was potassium iodide based on a comparative experimental study. Finally, the SERS spectrum of scopolamine hydrobromide was detected in aqueous solution, and the semi-quantitative analysis and the recovery rate were determined via a linear fitting. The detection limit of scopolamine hydrobromide in aqueous solution was 0.5 μg/mL. From 0 - 10 μg/mL, the curve of the intensity of the Raman characteristic peak of scopolamine hydrobromide at 1002 cm -1 is y = 4017.76 + 642.47x. The correlation coefficient was R 2 = 0.983, the recovery was 98.5 - 109.7%, and the relative standard deviation (RSD) was about 5.5%. This method is fast, accurate, non-destructive and simple for the detection of scopolamine hydrobromide.

Solid phase extraction--non-aqueous capillary electrophoresis for determination of metformin, phenformin and glyburide in human plasma.

PubMed

Lai, Edward P C; Feng, Sherry Y

2006-10-20

Solid phase extraction (SPE) was coupled at line to capillary electrophoresis (CE) for the determination of three basic and neutral diabetic drugs (metformin, phenformin and glyburide) in human plasma. The SPE procedure employed a C(18) cartridge to remove most of the water and proteins from the plasma sample. Analyte detectability was increased due to trace enrichment during the SPE process. Elution of metformin, phenformin and glyburide was achieved with methanol+3% acetic acid. CE analysis was performed using a non-aqueous buffer, acetonitrile+5mM ammonium acetate+5% acetic acid, which afforded rapid separation of metformin from phenformin within 3 min. Glyburide, with a migration time longer than 6 min, did not cause any interference. The present SPE-CE method, with an electrokinetic injection time of 6s and UV detection at 240 nm, was useful for monitoring down to 1 microg/mL of metformin and phenformin in human plasma. When the electrokinetic injection time was increased to 36s, the detection limits were improved to 12 ng/mL for metformin and 6 ng/mL for phenformin.

Gas Transport and Detection Following Underground Nuclear Explosions

NASA Astrophysics Data System (ADS)

Carrigan, C. R.; Sun, Y.; Wagoner, J. L.; Zucca, J. J.

2011-12-01

Some extremely rare radioactive noble gases are by-products of underground nuclear explosions, and the detection of significant levels of these gases (e.g., Xe-133 and Ar-37) at the surface is a very strong indicator of the occurrence of an underground nuclear event. Because of their uniqueness, such noble gas signatures can be confirmatory of the nuclear nature of an event while signatures from other important detection methods, such as anomalous seismicity, are generally not. As a result, noble gas detection at a suspected underground nuclear test site is considered to be the most important technique available to inspectors operating under the On-Site-Inspection protocol of the Comprehensive Nuclear Test Ban Treaty. A one-kiloton chemical underground explosion, the Non-Proliferation Experiment (NPE), was carried out at the Nevada Test Site in 1993 and represented the first On-Site-Inspection oriented test of subsurface gas transport with subsequent detection at the surface using soil gas sampling methods. A major conclusion of the experiment was that noble gases from underground nuclear tests have a good possibility of being detected even if the test is well contained. From this experiment and from computer simulations, we have also learned significant lessons about the modes of gas transport to the surface and the importance of careful subsurface sampling to optimize the detected noble gas signature. Understanding transport and sampling processes for a very wide range of geologic and testing scenarios presents significant challenges that we are currently addressing using sensitivity studies, which we attempt to verify using experiments such as the NPE and a new subsurface gas migration experiment that is now being undertaken at the National Center for Nuclear Security. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Thermographic observation of heat transport in solid foams

NASA Astrophysics Data System (ADS)

Netzelmann, U.; Abuhamad, M.; Walle, G.

2005-06-01

Heat transport in solid foams was studied by flash lamp heated dynamic thermography. For polyurethane foams, a movement of the peak temperature from the heated surface into the depth could be observed. This could be modelled by assuming a Beer optical absorber with non-adiabatic boundary. For large open pores, individual temperature-time curves were observed in the thermographic image. There is evidence for non-conductive heat transfer in the bulk of mixed-cell foams. In SiSiC ceramic foams, indications for sub-surface defects were detected.

Property Changes in Aqueous Solutions due to Surfactant Treatment of PCE: Implications to Geophysical Measurements

NASA Astrophysics Data System (ADS)

Werkema, D. D.

2007-12-01

Select physicochemical properties of aqueous solutions composed of surfactants, dye, and perchloroethylene (PCE) were evaluated through a response surface quadratic design model of experiment. Nine surfactants, which are conventionally used in the remediation of PCE, were evaluated with varying concentrations of PCE and indicator dyes in aqueous solutions. Two hundred forty experiments were performed using PCE as a numerical factor (coded A) from 0 to 200 parts per million (ppm), dye type (coded B) as a 3-level categorical factor, and surfactant type (coded C) as a 10-level categorical factor. Five responses were measured: temperature (°C), pH, conductivity (μS/cm), dissolved oxygen (DO, mg/L), and density (g/mL). Diagnostics proved a normally distributed predictable response for all measured responses except pH. The Box-Cox plot for transforms recommended a power transform for the conductivity response with lambda (λ) = 0.50, and for the DO response, λ =2.2. The overall mean of the temperature response proved to be a better predictor than the linear model. The conductivity response is best fitted with a linear model using significant coded terms B and C. Both DO and density also showed a linear model with coded terms A, B, and C for DO; and terms A and C for density. Some of the surfactant treatments of PCE significantly alter the conductivity, DO, and density of the aqueous solution. However, the magnitude of the density response is so small that it does not exceed the instrument tolerance. Results for the conductivity and DO responses provide predictive models for the surfactant treatment of PCE and may be useful in determining the potential for geophysically monitoring surfactant enhanced aquifer remediation (SEAR) of PCE. As the aqueous physicochemical properties change due to surfactant remediation efforts, so will the properties of the subsurface pore water which are influential factors in geophysical measurements. Geoelectrical methods are potentially the best suited to measure SEAR alterations in the subsurface because the conductivity of the pore fluid has the largest relative change. This research has provided predictive models for alterations in the physicochemical properties of the pore fluid to SEAR of PCE. Future investigations should address the contribution of the solid matrix in the subsurface and the solid-fluid interaction during SEAR of PCE contamination. Notice: Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy. Mention of trade names or commercial products does not constitute endorsement or recommendation by EPA for use.

Temporary vs. Permanent Sub-slab Ports: A Comparative ...

EPA Pesticide Factsheets

Vapor intrusion (VI) is the migration of subsurface vapors, including radon and volatile organic compounds (VOCs), from the subsurface to indoor air. The VI exposure pathway extends from the contaminant source, which can be impacted soil, non-aqueous phase liquid, or contaminated groundwater, to indoor air-exposure points. Therefore, contaminated matrices may include groundwater, soil, soil gas, and indoor air. VOC contaminants of concern typically include halogenated solvents such as trichloroethene, tetrachloroethene, and chloroform, as well as petroleum hydrocarbons, such as the aromatic VOCs benzene, toluene, and xylenes. Radon is a colorless radioactive gas that is released by radioactive decay of radionuclides in rock and soil that migrate into homes through VI in a similar fashion to VOCs. This project focused on the performance of permanent versus temporary sub-slab sampling ports for the determination of VI of halogenated VOCs and radon into an unoccupied house. VOC and radon concentrations measured simultaneously in soil gas using collocated temporary and permanent ports appeared to be independent of the type of port. The variability between collocated temporary and permanent ports was much less than the spatial variability between different locations within a single residential duplex. The agreement of the majority of VOC and radon concentrations, 0–36% relative percent difference, and 2–19% relative standard deviation respectively, of each sub-sl

Ceres' Evolution Before and After Dawn: Where are We Now?

NASA Astrophysics Data System (ADS)

McCord, T. B.; Castillo, J. C.

2016-12-01

Observations of Ceres before Dawn indicated that it contains 25 wt% water, and thermodynamic modeling indicated Ceres probably had experienced the same process of differentiation due to melting of the original ice after accretion as experienced by large icy moons. Consistent with that was a surface of altered mineralogy like clays suggesting aqueous alteration of the original chondritic silicates. Dawn has revealed some concentration of mass toward the center, specific aqueously altered mineralogies, a stiff surface with weaker material beneath, and extrusions and protrusions suggesting recent subsurface activity, including exposures of water ice that must be very recent. This wealth of new information from Dawn enables selection of more specific evolution models that best match the vastly improved Dawn observations. In this new study we propose one possibility is that Ceres accreted as an ice and silicate mixture after short-lived radionuclides in CAIs had significantly decayed, i.e. nearer 5 my after CAIs, and thus differentiated less completely than for hotter models. On the other hand, the presence of heavily aqueously altered mineralogies, including probably salts, suggests extensive mixing of water and silicates, which might normally be associated with more complete differentiation. Geologically recent activity, perhaps even to the present time, seems evident from several young landforms, including protrusions consistent with diapirism and recent exposures of water ice. This suggests recent flexing of the subsurface and rising of less dense interior material, including salts and ice. The presence of ammoniated minerals and what appear to be salt deposits suggest a major lowering of subsurface water ice melting temperature, enhancing the duration of water-silicate contact, and perhaps accelerating the mineralization processes and slowing or halting differentiation of water and silicates. Thus, Ceres is becoming known as the first body outward from the Sun that has had its evolution controlled by water-driven processes. Investigations of its interior and geology enable by Dawn's observations will in turn help to better understand other ice-rich bodies.

Ceres' evolution before and after Dawn: Where are we now?

NASA Astrophysics Data System (ADS)

McCord, Thomas B.; Castillo-Rogez, Julie C.

2016-10-01

Observations of Ceres before Dawn indicated that it contains ~25 wt% water, and thermodynamic modeling indicated Ceres probably had experienced the same process of differentiation due to melting of the original ice after accretion as experienced by large icy moons. Consistent with that was a surface of altered mineralogy like clays suggesting aqueous alteration of the original chondritic silicates. Dawn has revealed some concentration of mass toward the center, specific aqueously altered mineralogies, a stiff surface with weaker material beneath, and extrusions and protrusions suggesting recent subsurface activity, including exposures of water ice that must be very recent. This wealth of new information from Dawn enables selection of more specific evolution models that best match the vastly improved Dawn observations. In this new study we propose one possibility is that Ceres accreted as an ice and silicate mixture after short-lived radionuclides in CAIs had significantly decayed, i.e. nearer 5 my after CAIs, and thus differentiated less completely than for hotter models. On the other hand, the presence of heavily aqueously altered mineralogies, including probably salts, suggests extensive mixing of water and silicates, which might normally be associated with more complete differentiation. Geologically recent activity, perhaps even to the present time, seems evident from several young landforms, including protrusions consistent with diapirism and recent exposures of water ice. This suggests recent flexing of the subsurface and rising of less dense interior material, including salts and ice. The presence of ammoniated minerals and what appear to be salt deposits suggest a major lowering of subsurface water ice melting temperature, enhancing the duration of water-silicate contact, and perhaps accelerating the mineralization processes and slowing or halting differentiation of water and silicates. Thus, Ceres is becoming known as the first body outward from the Sun that has had its evolution controlled by water-driven processes. Investigations of its interior and geology enable by Dawn's observations will in turn help to better understand other ice-rich bodies.

Radar signal pre-processing to suppress surface bounce and multipath

DOEpatents

Paglieroni, David W; Mast, Jeffrey E; Beer, N. Reginald

2013-12-31

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes that return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

Spatially assisted down-track median filter for GPR image post-processing

DOEpatents

Paglieroni, David W; Beer, N Reginald

2014-10-07

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

Spatially adaptive migration tomography for multistatic GPR imaging

DOEpatents

Paglieroni, David W; Beer, N. Reginald

2013-08-13

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

Synthetic aperture integration (SAI) algorithm for SAR imaging

DOEpatents

Chambers, David H; Mast, Jeffrey E; Paglieroni, David W; Beer, N. Reginald

2013-07-09

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

Zero source insertion technique to account for undersampling in GPR imaging

DOEpatents

Chambers, David H; Mast, Jeffrey E; Paglieroni, David W

2014-02-25

A method and system for detecting the presence of subsurface objects within a medium is provided. In some embodiments, the imaging and detection system operates in a multistatic mode to collect radar return signals generated by an array of transceiver antenna pairs that is positioned across the surface and that travels down the surface. The imaging and detection system pre-processes the return signal to suppress certain undesirable effects. The imaging and detection system then generates synthetic aperture radar images from real aperture radar images generated from the pre-processed return signal. The imaging and detection system then post-processes the synthetic aperture radar images to improve detection of subsurface objects. The imaging and detection system identifies peaks in the energy levels of the post-processed image frame, which indicates the presence of a subsurface object.

Transport of Chemical Vapors from Subsurface Sources to Atmosphere as Affected by Shallow Subsurface and Atmospheric Conditions

NASA Astrophysics Data System (ADS)

Rice, A. K.; Smits, K. M.; Hosken, K.; Schulte, P.; Illangasekare, T. H.

2012-12-01

Understanding the movement and modeling of chemical vapor through unsaturated soil in the shallow subsurface when subjected to natural atmospheric thermal and mass flux boundary conditions at the land surface is of importance to applications such as landmine detection and vapor intrusion into subsurface structures. New, advanced technologies exist to sense chemical signatures at the land/atmosphere interface, but interpretation of these sensor signals to make assessment of source conditions remains a challenge. Chemical signatures are subject to numerous interactions while migrating through the unsaturated soil environment, attenuating signal strength and masking contaminant source conditions. The dominant process governing movement of gases through porous media is often assumed to be Fickian diffusion through the air phase with minimal or no quantification of other processes contributing to vapor migration, such as thermal diffusion, convective gas flow due to the displacement of air, expansion/contraction of air due to temperature changes, temporal and spatial variations of soil moisture and fluctuations in atmospheric pressure. Soil water evaporation and interfacial mass transfer add to the complexity of the system. The goal of this work is to perform controlled experiments under transient conditions of soil moisture, temperature and wind at the land/atmosphere interface and use the resulting dataset to test existing theories on subsurface gas flow and iterate between numerical modeling efforts and experimental data. Ultimately, we aim to update conceptual models of shallow subsurface vapor transport to include conditionally significant transport processes and inform placement of mobile sensors and/or networks. We have developed a two-dimensional tank apparatus equipped with a network of sensors and a flow-through head space for simulation of the atmospheric interface. A detailed matrix of realistic atmospheric boundary conditions was applied in a series of experiments. Water saturation, capillary pressure, air and soil temperature, and relative humidity were continuously monitored. Aqueous TCE was injected into the tank below the water table and allowed to volatilize. TCE concentration exiting the tank head space was measured through interval sampling by direct injection into a gas chromatograph. To quantify the transient concentration of TCE vapor in the soil pore space a novel use of Solid Phase Micro-Extraction (SPME) was developed. Results from our numerical simulations were compared with the experimental data, which demonstrated the importance of considering the interaction of the atmosphere with the subsurface in conceptualization and numerical model development. Results also emphasize that soil saturation and transient sorption have a significant effect on vapor transport through the vadose zone. Follow-up tests and detailed analyses are still underway. Additional applications of this work include carbon sequestration leakage, methane contamination in the shallow subsurface and environmental impact of hydraulic fracturing.

The Role of H2O in the Carbonation of Forsterite in Supercritical CO2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwak, Ja Hun; Hu, Jian Z.; Turcu, Romulus VF

2011-07-01

The water concentration dependence of forsterite carbonation in supercritical CO2 (scCO2) at 80°C and 76 bars was investigated by a combination of NMR, XRD, TEM and XPS. Reaction products were not detected using scCO2 alone without added H2O. When trace amounts of water were included, limited reaction was observed. Below saturation, reaction products were a mixture of partially hydrated/hydroxylated magnesium carbonates and hydroxylated silica species that were mainly in an amorphous state, forming a non-resolved layer on the forsterite surface. At water concentrations above saturation, where forsterite was in contact with both a CO2-saturated aqueous fluid and a water-saturated scCO2more » fluid, solid reaction products were magnesite (MgCO3) and an amorphous polymerized SiO2 dominated by Q4, and to a lesser extent by Q3 silica coordination. Formation of these phases implies H2O initially bound in precursor hydrated/hydroxylated reaction products was liberated, inducing further reaction. Hence, for a given fluid/mineral ratio there is a water threshold above which a significant portion of the water serves in a catalytic role where more extensive carbonation reaction occurs. Defining the role of water, even in low water content environments, is therefore critical to determining the long term impact of CO2 reactivity in the subsurface.« less

UV irradiation experiments under simulated martian surface conditions: Bio-effects on glycine, phage T7 and isolated T7 DNA

NASA Astrophysics Data System (ADS)

Bérces, Attila; ten Kate, I. L.; Fekete, A.; Hegedus, M.; Garry, J. R. C.; Lammer, Helmut; Ehrenfreund, Pascale; Peeters, Zan; Kovacs, G.; Ronto, G.

Mars is considered as a main target for astrobiologically relevant exploration programmes. In order to explain the non-detection of organic material to a detection level of several parts per billion (ppb) by the Viking landers, several hypotheses have been suggested, including degradation processes occurring on the martian surface and in the martian soil and subsurface. UV exposure experiments have been performed in which thin layers of glycine ( 300 nm), and aqueous suspensions of phage T7 and isolated T7 DNA were irradiated with a Deuterium lamp and for comparison with a Xenon arc lamp, modified to simulate the solar irradiation on the surface of Mars (MarsUV). The glycine sample was subjected to 24 hours of irradiation with MarsUV. The results of this glycine experiment show a destruction rate comparable to the results of previous experiments in which thin layers of glycine were irradiated with a deuterium lamp (ten Kate et al., 2005, 2006). After exposure of different doses of simulated Martian UV radiation a decrease of the biological activity of phages and characteristic changes in the UV absorption spectrum have been detected, indicating the UV damage of isolated and intraphage T7 DNA. The results of our experiments show that intraphage DNA is 4 times more sensitive to simulated martian UV and deuterium lamp radiation than isolated T7 DNA. This result indicates the significant role that phage proteins play in the UV damage. The effect of simulated martian radiation is smaller than the biological defects observed after the exposure with a deuterium lamp for both cases, in intraphage and isolated DNA, despite of the 100 times larger intensity of the MarsUV lamp. The detected spectral differences are about ten times smaller; the biological activity is about 3 - 4 times smaller, indicating that the shorter wavelength UV radiation from the deuterium lamp is more effective in inducing DNA damage, irrespective of being intraphage or isolated.

Potent Chemopreventive/Antioxidant Activity Detected in Common Spices of the Apiaceae Family.

PubMed

Jeyabalan, Jeyaprakash; Aqil, Farrukh; Soper, Lisa; Schultz, David J; Gupta, Ramesh C

2015-01-01

Spices are used worldwide, particularly in the Asian and Middle Eastern countries, and considered protective against degenerative diseases, including cancer. Here, we report the efficacy of aqueous and non-aqueous extracts of 11 Apiaceae spices for free radical-scavenging activity and to inhibit cytochrome P450s in two separate reactions involving: 1) 4-hydroxy-17ß-estradiol (4E2), DNA, and CuCl2 and 2) 17ß-estradiol, rat liver microsomes, cofactors, DNA and CuCl2. Oxidative DNA adducts resulting from redox cycling of 4E2 were analyzed by (32)P-postlabeling. Aqueous (5 mg/ml) and non-aqueous extracts (6 mg/ml) substantially inhibited (83-98%) formation of DNA adducts in the microsomal reaction. However, in nonmicrosomal reaction, only aqueous extracts showed the inhibitory activity (83-96%). Adduct inhibition was also observed at five-fold lower concentrations of aqueous extracts of cumin (60%) and caraway (90%), and 10-fold lower concentrations of carrot seeds (76%) and ajowan (90%). These results suggests the presence of 2 groups of phytochemicals: polar compounds that have free radical-scavenging activity and lipophilic compounds that selectively inhibit P450 activity associated with estrogen metabolism. Because most of these Apiaceae spices are used widely with no known toxicity, the phytochemicals from the Apiaceae spices used in foods may be potentially protective against estrogen-mediated breast cancer.

Molecular species forming at the α-Fe2O3 nanoparticle-aqueous solution interface.

PubMed

Ali, Hebatallah; Seidel, Robert; Pohl, Marvin N; Winter, Bernd

2018-05-21

We report on electronic structure measurements of the interface between hematite nanoparticles (6 nm diameter) and aqueous solutions. Using soft X-ray photoelectron spectroscopy from a liquid microjet we detect valence and core-level photoelectrons as well as Auger electrons from liquid water, from the nanoparticle-water interface, and from the interior of the aqueous-phase nanoparticles. Most noteworthy, the method is shown to be sufficiently sensitive for the detection of adsorbed hydroxyl species, resulting from H 2 O dissociation at the nanoparticle surface in aqueous solution. We obtain signal from surface OH from resonant, non-resonant, and from so-called partial-electron-yield X-ray absorption (PEY-XA) spectra. In addition, we report resonant photoelectron measurements at the iron 2p excitation. The respective Fe iron 2p 3/2 edge (L 3 -edge) PEY-XA spectra exhibit two main absorption peaks with their energies being sensitive to the chemical environment of the Fe 3+ ions at the nanoparticle-solution interface. This manifests in the 10 D q value which is a measure of the ligand-field strength. Furthermore, an observed intensity variation of the pre-peak, when comparing the PEY-XA spectra for different iron Auger-decay channels, can be assigned to different extents of electron delocalization. From the experimental fraction of local versus non-local autoionization signals we then find a very fast, approximately 1 fs, charge transfer time from interfacial Fe 3+ into the environment. The present study, which is complementary to ambient-pressure photoemission studies on solid-electrolyte systems, also highlights the multiple aspects of photoemission that need to be explored for a full characterization of the transition-metal-oxide nanoparticle surface in aqueous phase.

The genome of Geobacter bemidjiensis, exemplar for the subsurface clade of Geobacter species that predominate in Fe(III)-reducing subsurface environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aklujkar, Muktak; Young, Nelson D; Holmes, Dawn

2010-01-01

Background. Geobacter species in a phylogenetic cluster known as subsurface clade 1 are often the predominant microorganisms in subsurface environments in which Fe(III) reduction is the primary electron-accepting process. Geobacter bemidjiensis, a member of this clade, was isolated from hydrocarbon-contaminated subsurface sediments in Bemidji, Minnesota, and is closely related to Geobacter species found to be abundant at other subsurface sites. This study examines whether there are significant differences in the metabolism and physiology of G. bemidjiensis compared to non-subsurface Geobacter species. Results. Annotation of the genome sequence of G. bemidjiensis indicates several differences in metabolism compared to previously sequenced non-subsurfacemore » Geobacteraceae, which will be useful for in silico metabolic modeling of subsurface bioremediation processes involving Geobacter species. Pathways can now be predicted for the use of various carbon sources such as propionate by G. bemidjiensis. Additional metabolic capabilities such as carbon dioxide fixation and growth on glucose were predicted from the genome annotation. The presence of different dicarboxylic acid transporters and two oxaloacetate decarboxylases in G. bemidjiensis may explain its ability to grow by disproportionation of fumarate. Although benzoate is the only aromatic compound that G. bemidjiensis is known or predicted to utilize as an electron donor and carbon source, the genome suggests that this species may be able to detoxify other aromatic pollutants without degrading them. Furthermore, G. bemidjiensis is auxotrophic for 4-aminobenzoate, which makes it the first Geobacter species identified as having a vitamin requirement. Several features of the genome indicated that G. bemidjiensis has enhanced abilities to respire, detoxify and avoid oxygen. Conclusion. Overall, the genome sequence of G. bemidjiensis offers surprising insights into the metabolism and physiology of Geobacteraceae in subsurface environments, compared to non-subsurface Geobacter species, such as the ability to disproportionate fumarate, more efficient oxidation of propionate, enhanced responses to oxygen stress, and dependence on the environment for a vitamin requirement. Therefore, an understanding of the activity of Geobacter species in the subsurface is more likely to benefit from studies of subsurface isolates such as G. bemidjiensis than from the non-subsurface model species studied so far.« less

Subsurface Contamination Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Y. Yuan

There are two objectives of this report, ''Subsurface Contamination Control''. The first is to provide a technical basis for recommending limiting radioactive contamination levels (LRCL) on the external surfaces of waste packages (WP) for acceptance into the subsurface repository. The second is to provide an evaluation of the magnitude of potential releases from a defective WP and the detectability of the released contents. The technical basis for deriving LRCL has been established in ''Retrieval Equipment and Strategy for Wp on Pallet'' (CRWMS M and O 2000g, 6.3.1). This report updates the derivation by incorporating the latest design information of themore » subsurface repository for site recommendation. The derived LRCL on the external surface of WPs, therefore, supercede that described in CRWMS M and O 2000g. The derived LRCL represent the average concentrations of contamination on the external surfaces of each WP that must not be exceeded before the WP is to be transported to the subsurface facility for emplacement. The evaluation of potential releases is necessary to control the potential contamination of the subsurface repository and to detect prematurely failed WPs. The detection of failed WPs is required in order to provide reasonable assurance that the integrity of each WP is intact prior to MGR closure. An emplaced WP may become breached due to manufacturing defects or improper weld combined with failure to detect the defect, by corrosion, or by mechanical penetration due to accidents or rockfall conditions. The breached WP may release its gaseous and volatile radionuclide content to the subsurface environment and result in contaminating the subsurface facility. The scope of this analysis is limited to radioactive contaminants resulting from breached WPs during the preclosure period of the subsurface repository. This report: (1) documents a method for deriving LRCL on the external surfaces of WP for acceptance into the subsurface repository; (2) provides a table of derived LRCL for nuclides of radiological importance; (3) Provides an as low as is reasonably achievable (ALARA) evaluation of the derived LRCL by comparing potential onsite and offsite doses to documented ALARA requirements; (4) Provides a method for estimating potential releases from a defective WP; (5) Provides an evaluation of potential radioactive releases from a defective WP that may become airborne and result in contamination of the subsurface facility; and (6) Provides a preliminary analysis of the detectability of a potential WP leak to support the design of an airborne release monitoring system.« less

Calibration of Complex Subsurface Reaction Models Using a Surrogate-Model Approach

EPA Science Inventory

Application of model assessment techniques to complex subsurface reaction models involves numerous difficulties, including non-trivial model selection, parameter non-uniqueness, and excessive computational burden. To overcome these difficulties, this study introduces SAMM (Simult...

Remote sensing capacity of Raman spectroscopy in identification of mineral and organic constituents

NASA Astrophysics Data System (ADS)

Chen, Bin; Stoker, Carol; Cabrol, Nathalie; McKay, Christopher P.

2007-09-01

We present design, integration and test results for a field Raman spectrometer science payload, integrated into the Mars Analog Research and Technology (MARTE) drilling platform. During the drilling operation, the subsurface Raman spectroscopy inspection system has obtained signatures of organic and mineral compositions. We also performed ground truth studies using both this field unit and a laboratory micro Raman spectrometer equipped with multiple laser excitation wavelengths on series of field samples including Mojave rocks, Laguna Verde salty sediment and Rio Tinto topsoil. We have evaluated laser excitation conditions and optical probe designs for further improvement. We have demonstrated promising potential for Raman spectroscopy as a non-destructive in situ, high throughput, subsurface detection technique, as well as a desirable active remote sensing tool for future planetary and space missions.

SIRE: A MIMO Radar for Landmine/IED Detection

DTIC Science & Technology

2013-04-30

pursuit) for image formation. This technique has been used for subsurface imaging in the image domain, producing ’CLEANer’ images (where prior knowledge...Astronomy and Astrophysics Supplement 15 (1974). [22] Karpat, E., “CLEAN technique to classify and detect objects in subsurface imaging ,” International

Investigation of the sensitivity of a cross-polarized light visualization system to detect subclinical erythema and dryness in women with vulvovaginitis.

PubMed

Farage, Miranda A; Singh, Mukul; Ledger, William J

2009-07-01

An enhanced visualization technique using polarized light (Syris v600 enhanced visualization system; Syris Scientific LLC, Gray, ME) detects surface and subsurface ( approximately 1 mm depth) inflammation. We sought to compare the Syris v600 system with unaided visual inspection and colposcopy of the female genitalia. Erythema and dryness of the vulva, introitus, vagina, and cervix were visualized and scored by each method in patients with and without vulvitis. Subsurface visualization was more sensitive in detecting genital erythema and dryness at all sites whether or not symptoms were present. Subsurface inflammation of the introitus, vagina, and cervix only was detected uniquely in women with vulvar vestibulitis syndrome (VVS). A subset of women presenting with VVS exhibited subclinical inflammation of the vulva vestibule and vagina (designated VVS/lichen sclerosus subgroup). Enhanced visualization of the genital epithelial subsurface with cross-polarized light may assist in diagnosing subclinical inflammation in vulvar conditions heretofore characterized as sensory syndromes.

Using electrokinetic phenomena and electrical resistance tomography to characterize the movement of subsurface fluids

DOEpatents

Ramirez, Abelardo L.; Cooper, John F.; Daily, William D.

1996-01-01

This invention relates generally to the remote detections of subsurface liquid contaminants using in combination a geophysical technique known as ERT and an EKS. Electrokinetic transport is used to enhance the ability of electrical resistance tomography (ERT) to detect position and movement of subsurface contaminant liquids, particles or ions. ERT images alone are difficult to interpret because of natural inhomogeneities in soil composition and electrical properties. By subtracting two or more ERT images obtained before and after field induced movement, a high contrast image of a plume of distinct electrokinetic properties can be seen. The invention is applicable to important subsurface characterization problems including, as examples, (1) detection of liquid-saturated plumes of contaminants such as those associated with leaks from underground storage tanks containing hazardous concentrated electrolytes, (2) detection and characterization of soils contaminated with organic pollutants such as droplets of gasoline; and (3) monitoring the progress of electrokinetic containment or clean up of underground contamination.

Using electrokinetic phenomena and electrical resistance tomography to characterize the movement of subsurface fluids

DOEpatents

Ramirez, A.L.; Cooper, J.F.; Daily, W.D.

1996-02-27

This invention relates generally to the remote detections of subsurface liquid contaminants using in combination a geophysical technique known as ERT and an EKS. Electrokinetic transport is used to enhance the ability of electrical resistance tomography (ERT) to detect position and movement of subsurface contaminant liquids, particles or ions. ERT images alone are difficult to interpret because of natural inhomogeneities in soil composition and electrical properties. By subtracting two or more ERT images obtained before and after field induced movement, a high contrast image of a plume of distinct electrokinetic properties can be seen. The invention is applicable to important subsurface characterization problems including, as examples, (1) detection of liquid-saturated plumes of contaminants such as those associated with leaks from underground storage tanks containing hazardous concentrated electrolytes, (2) detection and characterization of soils contaminated with organic pollutants such as droplets of gasoline; and (3) monitoring the progress of electrokinetic containment or clean up of underground contamination. 1 fig.

Membrane separation for non-aqueous solution

NASA Astrophysics Data System (ADS)

Widodo, S.; Khoiruddin; Ariono, D.; Subagjo; Wenten, I. G.

2018-01-01

Membrane technology has been widely used in a number of applications competing with conventional technologies in various ways. Despite the enormous applications, they are mainly used for the aqueous system. The use of membrane-based processes in a non-aqueous system is an emerging area. This is because developed membranes are still limited in separations involving aqueous solution which show several drawbacks when implemented in a non-aqueous system. The purpose of this paper is to provide a review of the current application of membrane processes in non-aqueous solutions, such as mineral oil treatment, vegetable oil processing, and organic solvent recovery. Developments of advanced membrane materials for the non-aqueous solutions such as super-hydrophobic and organic solvent resistant membranes are reviewed. In addition, challenges and future outlook of membrane separation for the non-aqueous solution are discussed.

The Serpentinite Subsurface Microbiome

NASA Astrophysics Data System (ADS)

Schrenk, M. O.; Nelson, B. Y.; Brazelton, W. J.

2011-12-01

Microbial habitats hosted in ultramafic rocks constitute substantial, globally-distributed portions of the subsurface biosphere, occurring both on the continents and beneath the seafloor. The aqueous alteration of ultramafics, in a process known as serpentinization, creates energy rich, high pH conditions, with low concentrations of inorganic carbon which place fundamental constraints upon microbial metabolism and physiology. Despite their importance, very few studies have attempted to directly access and quantify microbial activities and distributions in the serpentinite subsurface microbiome. We have initiated microbiological studies of subsurface seeps and rocks at three separate continental sites of serpentinization in Newfoundland, Italy, and California and compared these results to previous analyses of the Lost City field, near the Mid-Atlantic Ridge. In all cases, microbial cell densities in seep fluids are extremely low, ranging from approximately 100,000 to less than 1,000 cells per milliliter. Culture-independent analyses of 16S rRNA genes revealed low-diversity microbial communities related to Gram-positive Firmicutes and hydrogen-oxidizing bacteria. Interestingly, unlike Lost City, there has been little evidence for significant archaeal populations in the continental subsurface to date. Culturing studies at the sites yielded numerous alkaliphilic isolates on nutrient-rich agar and putative iron-reducing bacteria in anaerobic incubations, many of which are related to known alkaliphilic and subsurface isolates. Finally, metagenomic data reinforce the culturing results, indicating the presence of genes associated with organotrophy, hydrogen oxidation, and iron reduction in seep fluid samples. Our data provide insight into the lifestyles of serpentinite subsurface microbial populations and targets for future quantitative exploration using both biochemical and geochemical approaches.

Mechanism of Uranium Reduction and Immobilization in Desulfovibrio vulgaris Biofilms.

PubMed

Stylo, Malgorzata; Neubert, Nadja; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan

2015-09-01

The prevalent formation of noncrystalline U(IV) species in the subsurface and their enhanced susceptibility to reoxidation and remobilization, as compared to crystalline uraninite, raise concerns about the long-term sustainability of the bioremediation of U-contaminated sites. The main goal of this study was to resolve the remaining uncertainty concerning the formation mechanism of noncrystalline U(IV) in the environment. Controlled laboratory biofilm systems (biotic, abiotic, and mixed biotic-abiotic) were probed using a combination of U isotope fractionation and X-ray absorption spectroscopy (XAS). Regardless of the mechanism of U reduction, the presence of a biofilm resulted in the formation of noncrystalline U(IV). Our results also show that biotic U reduction is the most effective way to immobilize and reduce U. However, the mixed biotic-abiotic system resembled more closely an abiotic system: (i) the U(IV) solid phase lacked a typically biotic isotope signature and (ii) elemental sulfur was detected, which indicates the oxidation of sulfide coupled to U(VI) reduction. The predominance of abiotic U reduction in our systems is due to the lack of available aqueous U(VI) species for direct enzymatic reduction. In contrast, in cases where bicarbonate is present at a higher concentration, aqueous U(VI) species dominate, allowing biotic U reduction to outcompete the abiotic processes.

Pre-processing of data coming from a laser-EMAT system for non-destructive testing of steel slabs.

PubMed

Sgarbi, Mirko; Colla, Valentina; Cateni, Sivia; Higson, Stuart

2012-01-01

Non destructive test systems are increasingly applied in the industrial context for their strong potentialities in improving and standardizing quality control. Especially in the intermediate manufacturing stages, early detection of defects on semi-finished products allow their direction towards later production processes according to their quality, with consequent considerable savings in time, energy, materials and work. However, the raw data coming from non destructive test systems are not always immediately suitable for sophisticated defect detection algorithms, due to noise and disturbances which are unavoidable, especially in harsh operating conditions, such as the ones which are typical of the steelmaking cycle. The paper describes some pre-processing operations which are required in order to exploit the data coming from a non destructive test system. Such a system is based on the joint exploitation of Laser and Electro-Magnetic Acoustic Transducer technologies and is applied to the detection of surface and sub-surface cracks in cold and hot steel slabs. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

Iodine conceptual model at Hanford: Aqueous speciation and interactions with minerals

NASA Astrophysics Data System (ADS)

Qafoku, N. P.; Lawter, A.; McElroy, E.; Szecsody, J. E.; Lee, B.; Truex, M. J.; Smith, F.; Kerisit, S.; Freedman, V. L.

2017-12-01

Isotopes of iodine were generated during plutonium production at the U.S. Department of Energy Hanford Site. The fate and transport of 129I in the environment and potential remediation technologies are currently being studied as part of environmental remediation activities at the Hanford Site. A conceptual model describing the nature and extent of subsurface contamination, processes and reactions that control plume behavior, and factors relevant to potential remediation processes is needed to support environmental remedy decisions. Because 129I is an uncommon contaminant, relevant remediation experience and scientific literature are limited. As part of the effort to develop a comprehensive conceptual model of iodine at the Hanford subsurface, we conducted a series of bench-scale experiments to determine the extent of iodine interactions with minerals, abiotic and biotic species transformation via electron transfer reactions, and mechanisms of iodine aqueous species attentuation (i.e., adsorption and co-precipitation). We will also present data collected from solid phase characterization efforts using SEM/EDS, SEM/FIB, TEM/SAED, XANES and NanoSIMS. Interactions of iodine species with natural organic matter are also important; we determined the identity of organic matter compounds at Hanford and their affinity for different aqueous iodine species (i.e., iodate and iodide) using FTICR-MS along with tandem mass spectrometry (MS/MS) to verify organo-iodide/iodate binding. Finally, we used a variety of molecular dymanic calculations to identify energetically competitive incorporation scenarios, and determine incorporation limits and charge compensation mechanisms.

Electrode Induced Removal and Recovery of Uranium (VI) from Acidic Subsurfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gregory, Kelvin

2013-08-12

The overarching objective of this research is to provide an improved understanding of how aqueous geochemical conditions impact the removal of U and Tc from groundwater and how engineering design may be utilized to optimize removal of these radionuclides. Experiments were designed to address the unique conditions in Area 3 of ORNL while also providing broader insight into the geochemical effectors of the removal rates and extent for U and Tc. The specific tasks of this work were to: 1) quantify the impact of common aqueous geochemical and operational conditions on the rate and extent of U removal and recoverymore » from water, 2) investigate the removal of Tc with polarized graphite electrode, and determine the influence of geochemical and operational conditions on Tc removal and recovery, 3) determine whether U and Tc may be treated simultaneous from Area 3 groundwater, and examine the bench-scale performance of electrode-based treatment, and 4) determine the capacity of graphite electrodes for U(VI) removal and develop a mathematical, kinetic model for the removal of U(VI) from aqueous solution. Overall the body of work suggests that an electrode-based approach for the remediation of acidic subsurface environments, such as those observed in Area 3 of ORNL may be successful for the removal for both U(VI) and Tc. Carbonaceous (graphite) electrode materials are likely to be the least costly means to maximize removal rates and efficiency by maximizing the electrode surface area.« less

Surface clay formation during short-term warmer and wetter conditions on a largely cold ancient Mars

NASA Astrophysics Data System (ADS)

Bishop, Janice L.; Fairén, Alberto G.; Michalski, Joseph R.; Gago-Duport, Luis; Baker, Leslie L.; Velbel, Michael A.; Gross, Christoph; Rampe, Elizabeth B.

2018-03-01

The ancient rock record for Mars has long been at odds with climate modelling. The presence of valley networks, dendritic channels and deltas on ancient terrains points towards running water and fluvial erosion on early Mars1, but climate modelling indicates that long-term warm conditions were not sustainable2. Widespread phyllosilicates and other aqueous minerals on the Martian surface3-6 provide additional evidence that an early wet Martian climate resulted in surface weathering. Some of these phyllosilicates formed in subsurface crustal environments5, with no association with the Martian climate, while other phyllosilicate-rich outcrops exhibit layered morphologies and broad stratigraphies7 consistent with surface formation. Here, we develop a new geochemical model for early Mars to explain the formation of these clay-bearing rocks in warm and wet surface locations. We propose that sporadic, short-term warm and wet environments during a generally cold early Mars enabled phyllosilicate formation without requiring long-term warm and wet conditions. We conclude that Mg-rich clay-bearing rocks with lateral variations in mixed Fe/Mg smectite, chlorite, talc, serpentine and zeolite occurrences formed in subsurface hydrothermal environments, whereas dioctahedral (Al/Fe3+-rich) smectite and widespread vertical horizonation of Fe/Mg smectites, clay assemblages and sulphates formed in variable aqueous environments on the surface of Mars. Our model for aluminosilicate formation on Mars is consistent with the observed geological features, diversity of aqueous mineralogies in ancient surface rocks and state-of-the-art palaeoclimate scenarios.

Generation and detection of gaseous W12O41-* and other tungstate anions by laser desorption ionization mass spectrometry.

PubMed

Pavlov, Julius; Braida, Washington; Ogundipe, Adebayo; O'Connor, Gregory; Attygalle, Athula B

2009-10-01

The presence of a peak centered near m/z 2862, observed for the first time for the caged dodecatungstate radical-anion, [W12O41]-*, enables distinguishing WO2 from WO3 by Laser Desorption Ionization mass spectrometry (LDI-MS). In addition to WO2, laser irradiation of dry deposits made from aqueous ammonium paratungstate, and calcium and lead orthotungstate also produce the [W12O41]-. In contrast, spectra recorded from deposits made from aqueous Na2WO4, sodium metatungstate, and WO3, or non-aqueous calcium and lead orthotungstate, and ammonium paratungstate, failed to show the m/z 2862 peak cluster. These observations support the hypothesis that polycondensation reactions to form [W12O41]-* occur solely in the presence of water. Although dry spots are irradiated for ionization, the solvent used for sample preparation plays an important role on the chemical composition endowed to ions detected. For example, the m/z 2862 peak seen from deposits made from aqueous ammonium paratungstate, and calcium and lead orthotungstate, is absent in the spectra recorded either from pristine deposits or those derived from solutions made with organic solvents such as acetonitrile or ethanol.

CAFFEINE SPECIFICITY OF VARIOUS NON-IMPRINTED POLYMERS IN AQUEOUS MEDIA

EPA Science Inventory

Limitations exist in applying the conventional microbial methods to the detection of human fecal contamination in water. Certain organic compounds such as caffeine, have been reported by the U.S. Geological Survey as a more suitable tracer. The employment of caffeine has been h...

Shallow Reflection Method for Water-Filled Void Detection and Characterization

NASA Astrophysics Data System (ADS)

Zahari, M. N. H.; Madun, A.; Dahlan, S. H.; Joret, A.; Hazreek, Z. A. M.; Mohammad, A. H.; Izzaty, R. A.

2018-04-01

Shallow investigation is crucial in enhancing the characteristics of subsurface void commonly encountered in civil engineering, and one such technique commonly used is seismic-reflection technique. An assessment of the effectiveness of such an approach is critical to determine whether the quality of the works meets the prescribed requirements. Conventional quality testing suffers limitations including: limited coverage (both area and depth) and problems with resolution quality. Traditionally quality assurance measurements use laboratory and in-situ invasive and destructive tests. However geophysical approaches, which are typically non-invasive and non-destructive, offer a method by which improvement of detection can be measured in a cost-effective way. Of this seismic reflection have proved useful to assess void characteristic, this paper evaluates the application of shallow seismic-reflection method in characterizing the water-filled void properties at 0.34 m depth, specifically for detection and characterization of void measurement using 2-dimensional tomography.

Device and nondestructive method to determine subsurface micro-structure in dense materials

DOEpatents

Sun, Jiangang [Westmont, IL

2006-05-09

A method and a device to detect subsurface three-dimensional micro-structure in a sample by illuminating the sample with light of a given polarization and detecting light emanating from the sample that has a different direction of polarization by means of a confocal optical system.

EVALUATION OF GEOPHYSICAL METHODS FOR THE DETECTION OF SUBSURFACE TETRACHLOROETHYLENE IN CONTROLLED SPILL EXPERIMENTS

EPA Science Inventory

The purpose of the work was to determine the capability of various geophysical methods to detect PCE in the subsurface. Measurements were made with ten different geophysical techniques before, during, and after the PCE injection. This approach provided a clear identification of a...

Textural evidence for jamming and dewatering of a sub-surface, fluid-saturated granular flow

NASA Astrophysics Data System (ADS)

Sherry, T. J.; Rowe, C. D.; Kirkpatrick, J. D.; Brodsky, E. E.

2011-12-01

Sand injectites are spectacular examples of large-scale granular flows involving migration of hundreds of cubic meters of sand slurry over hundreds of meters to kilometers in the sub-surface. By studying the macro- and microstructural textures of a kilometer-scale sand injectite, we interpret the fluid flow regimes during emplacement and define the timing of formation of specific textures in the injected material. Fluidized sand sourced from the Santa Margarita Fm., was injected upward into the Santa Cruz Mudstone, Santa Cruz County, California. The sand injectite exposed at Yellow Bank Beach records emplacement of both hydrocarbon and aqueous sand slurries. Elongate, angular mudstone clasts were ripped from the wall rock during sand migration, providing evidence for high velocity, turbid flow. However, clast long axis orientations are consistently sub-horizontal suggesting the slurry transitioned to a laminar flow as the flow velocity decreased in the sill-like intrusion. Millimeter to centimeter scale laminations are ubiquitous throughout the sand body and are locally parallel to the mudstone clast long axes. The laminations are distinct in exposure because alternating layers are preferentially cemented with limonite sourced from later groundwater infiltration. Quantitative microstructural analyses show that the laminations are defined by subtle oscillations in grain alignment between limonite and non-limonite stained layers. Grain packing, size and shape distributions do not vary. The presence of limonite in alternating layers results from differential infiltration of groundwater, indicating permeability changes between the layers despite minimal grain scale differences. Convolute dewatering structures deform the laminations. Dolomite-cemented sand, a signature of hydrocarbon saturation, forms irregular bodies that cross-cut the laminations and dewatering structures. Laminations are not formed in the dolomite-cemented sand. The relative viscosity difference between the hydrocarbon and aqueous sand slurries controls the the critical radius of the contacts between dolomite cemented and limonite cemented sand bodies. The cross-cutting relationships established in the field show that the laminations formed at the jamming transition in the aqueous sand slurry. We interpret the laminations as preserving evidence for dynamic permeability instabilities in the dewatering slurry. Relatively high permeability channels formed as pore fluid flow rearranged grains during initial dewatering. Once initiated, the flow localized further into the higher permeability channels resulting in a feedback that caused the permeability in the channels to increase.

Low-Energy Water Recovery from Subsurface Brines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Young Chul; Kim, Gyu Dong; Hendren, Zachary

A novel non-aqueous phase solvent (NAS) desalination process was proposed and developed in this research project. The NAS desalination process uses less energy than thermal processes, doesn’t require any additional chemicals for precipitation, and can be utilized to treat high TDS brine. In this project, our experimental work determined that water solubility changes and selective absorption are the key characteristics of NAS technology for successful desalination. Three NAS desalination mechanisms were investigated: (1) CO2 switchable, (2) high-temp absorption to low-temp desorption (thermally switchable), and (3) low-temp absorption to high-temp desorption (thermally switchable). Among these mechanisms, thermally switchable (low-temp absorption tomore » high-temp desorption) showed the highest water recovery and relatively high salt rejection. A test procedure for semi-continuous, bench scale NAS desalination process was also developed and used to assess performance under a range of conditions.« less

Ion chromatographic determination of hydrolysis products of hexafluorophosphate salts in aqueous solution.

PubMed

Terborg, Lydia; Nowak, Sascha; Passerini, Stefano; Winter, Martin; Karst, Uwe; Haddad, Paul R; Nesterenko, Pavel N

2012-02-10

In this work, hydrolysis of three different hexafluorophosphate salts in purified water was investigated. Aqueous samples of lithium hexafluorophosphate (LiPF(6)), sodium hexafluorophosphate (NaPF(6)) and potassium hexafluorophosphate (KPF(6)) were prepared and stored for different times. Ion chromatography (IC) with UV as well as non-suppressed and suppressed conductivity detection was used for the analysis of the reaction products. For the detection and identification of the formed decomposition products, an IC method using IonPac AS14A 250 mm × 4.0 mm i.d. column and 2.5 mM KHCO(3)-2.5 mM K(2)CO(3) eluent was established. Besides hexafluorophosphate, four other anionic species were detected in fresh and matured aqueous solutions. The hydrolysis products fluoride (F(-)), monofluorophosphate (HPO(3)F(-)), phosphate (HPO(4)(2-)) and difluorophosphate (PO(2)F(2)(-)) were found and were unambiguously identified by means of standards or electrospray ionization mass spectrometry (ESI-MS). It was shown that stability of hexafluorophosphate solutions depends on the nature of the counter ion and decreases in the order potassium>sodium>lithium. Copyright © 2011 Elsevier B.V. All rights reserved.

Influence of deep vortices on the ocean surface

NASA Astrophysics Data System (ADS)

Ciani, Daniele; Carton, Xavier; Bashmachnikov, Igor; Chapron, Bertrand

2015-04-01

The oceanic motion at mesoscale (20-200 km) and submesoscale (0.5-20 km) is highly populated by vortices. These recirculating structures are more energetic than the mean flow, they trap water masses from their origination areas and advect them across the ocean, with consequent impact on the 3D distribution of heat and tracers. Mesoscale and submesoscale structures characterize the ocean dynamics both at the sea-surface and at intrathermocline depths (0-1500 m), and are presently investigated by means of model outputs and satellite (surface) data, the latest being the only way to get high resolution and synoptic observations at planetary scale (e.g., thermal-band observations, future altimetric observations given by the SWOT mission). The scientific question arising from this context is related to the role of the ocean surface for inferring informations on mesoscale and submesoscale vortices at depth. This study has also been motivated by the recent detection of subsurface eddies east of the Arabian Peninsula (PHYSINDIEN experiment - 2011). Using analytical models in the frame of the quasi-geostrophic (QG) theory, we could describe the theoretical altimetric signature of non-drifting and of drifting subsurface eddies. Numerical experiments, using both QG and primitive equations models, allowed us to investigate the surface expression of intrathermocline eddies interacting with baroclinic currents or evolving under planetary beta-effect. The eddies' characteristics (radius, depth, thickness, velocity) were varied in order to represent various oceanic examples (Meddies, Swoddies, Reddies, Peddies, Leddies). Idealized simulations with the ROMS model, confirming theoretical estimates, showed that drifting subsurface-intensified vortices can induce dipolar sea level anomalies, up to 3 cm. This result, compatibly with future SWOT measurement accuracies (about 2 cm), represents a contribution for systematic and synoptic detection of subsurface vortices.

Expanded separation technique for chlorophyll metabolites in Oriental tobacco leaf using non aqueous reversed phase chromatography.

PubMed

Ishida, Naoyuki

2011-08-26

An improved separation method for chlorophyll metabolites in Oriental tobacco leaf was developed. While Oriental leaf still gives the green color even after the curing process, little attention has been paid to the detailed composition of the remaining green pigments. This study aimed to identify the green pigments using non aqueous reversed phase chromatography (NARPC). To this end, liquid chromatograph (LC) equipped with a photo diode array detector (DAD) and an atmospheric pressure chemical ionization/mass spectrometer (APCI/MSD) was selected, because it is useful for detecting low polar non-volatile compounds giving green color such as pheophytin a. Identification was based on the wavelength spectrum, mass spectrum and retention time, comparing the analytes in Oriental leaf with the commercially available and synthesized components. Consequently, several chlorophyll metabolites such as hydroxypheophytin a, solanesyl pheophorbide a and solanesyl hydroxypheophorbide a were newly identified, in addition to typical green pigments such as chlorophyll a and pheophytin a. Chlorophyll metabolites bound to solanesol were considered the tobacco specific components. NARPC expanded the number of detectable low polar chlorophyll metabolites in Oriental tobacco leaf. Copyright © 2011 Elsevier B.V. All rights reserved.

EPA Method 8321B (SW-846): Solvent-Extractable Nonvolatile Compounds by High Performance Liquid Chromatography-Thermospray-Mass Spectrometry (HPLC-TS-MS) or Ultraviolet (UV) Detection

EPA Pesticide Factsheets

Method 8321B describes procedures for preparation and analysis of solid, aqueous liquid, drinking water and wipe samples using high performance liquid chromatography and mass spectrometry for extractable non-volatile compounds.

Non-Equilibrium Thermodynamic Chemistry and the Composition of the Atmosphere of Mars

NASA Technical Reports Server (NTRS)

Levine, J. S.; Summers, M. E.

2003-01-01

A high priority objective of the Mars Exploration Program is to Determine if life exists today (MEPAG Goal I, Objective A). The measurement of gases of biogenic origin may be an approach to detect the presence of microbial life on the surface or subsurface of Mars. Chemical thermodynamic calculations indicate that on both Earth and Mars, certain gases should exist in extremely low concentrations, if at all. Microbial metabolic activity is an important non-equilibrium chemistry process on Earth, and if microbial life exists on Mars, may be an important nonequilibrium chemistry process on Mars. The non-equilibrium chemistry of the atmosphere of Mars is discussed in this paper.

Non-aqueous capillary electrophoresis for separation and simultaneous determination of fraxin, esculin and esculetin in Cortex fraxini and its medicinal preparations.

PubMed

Li, Cunhong; Chen, Anjia; Chen, Xiaofeng; Ma, Xiao; Chen, Xingguo; Hu, Zhide

2005-11-01

A non-aqueous capillary electrophoresis method has been developed for the separation and simultaneous determination of fraxin, esculin and esculetin in Cortex fraxini and its preparation for the first time. Optimum separation of the analytes was obtained on a 47 cm x 75 microm i.d. fused-silica capillary using a non-aqueous buffer system of 60 mM sodium cholate, 20 mM ammonium acetate, 20% acetonitrile and 3% acetic acid at 20 kV and 292 K, respectively. The relative standard deviations (RSDs) of the migration times and the peak heights of the three analytes were in the range of 0.23-0.28 and 2.12-2.60%, respectively. Detection limits of fraxin, esculin and esculetin were 0.1557, 0.4073 and 0.5382 microg/mL, respectively. In the tested concentration range, good linear relationships (correlation coefficients 0.9995 for fraxin, 0.9999 for esculin and 0.9992 for esculetin) between peak heights and concentrations of the analytes were observed. This method has been successfully applied to simultaneous determination of the three bioactive components with the recoveries from 90.2 to 109.2% in the five samples.

Layering extraction from subsurface radargrams over Greenland and the Martian NPLD by combining wavelet analysis with Hough transforms

NASA Astrophysics Data System (ADS)

Xiong, Si-Ting; Muller, Jan-Peter

2017-04-01

Extracting lines from an imagery is a solved problem in the field of edge detection. Different to images taken by camera, radargrams are a set of radar echo profiles, which record wave energy reflected by subsurface reflectors, at each location of a radar footprint along the satellite's ground track. The radargrams record where there is a dielectric contrast caused by different deposits, and other subsurface features, such as facies, and internal distributions like porosity and fluids. Among the subsurface features, layering is an important one which reflect the sequence of seasonal or yearly deposits on the ground [1-2]. In the field of image processing, line detection methods, such as the Radon Transform or Hough Transform, are able to extract these subsurface layers from rasterised versions of the echograms. However, due to the attenuation of radar waves whilst propagating through geological media, radargrams sometimes suffer from gradient and high background noise. These attributes of radargrams cause errors in detection when conventional line detection methods are directly applied. In this study, we have developed a continuous wavelet analysis technique to be applied directly to the radar echo profiles in a radargram in order to detect segmented lines, and then a conventional line detection method, such as a Hough transform can be applied to connect these segmented lines. This processing chain is tested by using datasets from a radargram acquired by the Multi-channel Coherent Radar Depth Sounder (MCoRDS) on an airborne platform in Greenland and a radargram acquired by the SHAllow RADar (SHARAD) on board the Mars Reconnaissance Orbiter (MRO) [3] over Martian North Polar Layered Deposits (NPLD). Keywords: Subsurface mapping, Radargram, SHARAD, Greenland, Martian NPLD, Subsurface layering, line detection References: [1] Phillips, R. J., et al. "Mars north polar deposits: Stratigraphy, age, and geodynamical response." Science 320.5880 (2008): 1182-1185. [2] Cutts, James A., and Blake H. Lewis. "Models of climate cycles recorded in Martian polar layered deposits." Icarus 50.2 (1982): 216-244. [3] Plaut J J, Picardi G, Safaeinili A, et al. Subsurface radar sounding of the south polar layered deposits of Mars[J]. science, 2007, 316(5821): 92-95. Acknowledgements: Part of the research leading to these results has received funding from the STFC "MSSL Consolidated Grant" ST/K000977/1 and partial support from the European Union's Seventh Framework Programme (FP7/2007-2013) under iMars grant agreement No. 607379 as well as from the China Scholarship Council and the UCL Dean of MAPS fund.

Looking For a Needle in the Haystack: Deciphering Indigenous 1.79 km Deep Subsurface Microbial Communities from Drilling Mud Contaminants Using 454 Pyrotag Sequencing

NASA Astrophysics Data System (ADS)

Dong, Y.; Cann, I.; Mackie, R.; Price, N.; Flynn, T. M.; Sanford, R.; Miller, P.; Chia, N.; Kumar, C. G.; Kim, P.; Sivaguru, M.; Fouke, B. W.

2010-12-01

Knowledge of the composition, structure and activity of microbial communities that live in deeply buried sedimentary rocks is fundamental to the future of subsurface biosphere stewardship as it relates to hydrocarbon exploration and extraction, carbon sequestration, gas storage and groundwater management. However, the study of indigenous subsurface microorganisms has been limited by the technical challenges of collecting deep formation water samples that have not been heavily contaminated by the mud used to drill the wells. To address this issue, a “clean-sampling method” deploying the newly developed Schlumberger Quicksilver MDT probe was used to collect a subsurface sample at a depth of 1.79 km (5872 ft) from an exploratory well within Cambrian-age sandstones in the Illinois Basin. This yielded a formation water sample that was determined to have less than 4% drilling mud contamination based on tracking changes in the aqueous geochemistry of the formation water during ~3 hours of pumping at depth prior to sample collection. A suite of microscopy and culture-independent molecular analyses were completed using the DNA extracted from microbial cells in the formation water, which included 454 amplicon pyrosequencing that targeted the V1-V3 hypervariable region of bacterial 16S rRNA gene sequences. Results demonstrated an extremely low diversity microbial community living in formation water at 1.79 km-depth. More than 95 % of the total V1-V3 pyrosequencing reads (n=11574) obtained from the formation water were affiliated with a halophilic γ-proteobacterium and most closely related to the genus Halomonas. In contrast, about 3 % of the V1-V3 sequences in the drilling mud library (n=13044) were classified as genus Halomonas but were distinctly different and distantly related to the formation water Halomonas detected at 1.79 km-depth. These results were consistent with those obtained using a suite of other molecular screens (e.g., Terminal-Restriction Fragment Length Polymorphism (T-RFLP) and the initial full length 16S rRNA amplicon libraries) and bioinformatic analyses (e.g., 16S rRNA and Open Reading Frame (ORF) calls established from the 454 metagenomic community analyses). Functional pathway modeling is underway to evaluate the adaptation of this indigenous microbial community to the hydrologic and geologic history of the deep subsurface environment of the Illinois Basin.

Antidiabetic activity of aqueous extract and non polysaccharide fraction of Cynodon dactylon Pers.

PubMed

Jarald, E E; Joshi, S B; Jain, D C

2008-09-01

Petroleum ether (60 degrees-80 degrees C), chloroform, acetone, ethanol, aqueous and crude hot water extracts of the whole plant of C. dactylon and the two fractions of aqueous extract were tested for antihyperglycaemic activity in glucose overloaded hyperglycemic rats and in alloxan induced diabetic model at two-dose levels, 200 and 400 mg/kg (po) respectively. The aqueous extract of C. dactylon and the non polysaccharide fraction of aqueous extract were found to exhibit significant antihyperglycaemic activity and only the non polysaccharide fraction was found to produce hypoglycemia in fasted normal rats. Treatment of diabetic rats with aqueous extract and non polysaccharide fraction of the plant decreased the elevated biochemical parameters, glucose, urea, creatinine, serum cholesterol, serum triglyceride, high density lipoprotein, low density lipoprotein, haemoglobin and glycosylated haemoglobin significantly. Comparatively, the non polysaccharide fraction of aqueous extract was found to be more effective than the aqueous extract.

Removing sulphur oxides from a fluid stream

DOEpatents

Katz, Torsten; Riemann, Christian; Bartling, Karsten; Rigby, Sean Taylor; Coleman, Luke James Ivor; Lail, Marty Alan

2014-04-08

A process for removing sulphur oxides from a fluid stream, such as flue gas, comprising: providing a non-aqueous absorption liquid containing at least one hydrophobic amine, the liquid being incompletely miscible with water; treating the fluid stream in an absorption zone with the non-aqueous absorption liquid to transfer at least part of the sulphur oxides into the non-aqueous absorption liquid and to form a sulphur oxide-hydrophobic amine-complex; causing the non-aqueous absorption liquid to be in liquid-liquid contact with an aqueous liquid whereby at least part of the sulphur oxide-hydrophobic amine-complex is hydrolyzed to release the hydrophobic amine and sulphurous hydrolysis products, and at least part of the sulphurous hydrolysis products is transferred into the aqueous liquid; separating the aqueous liquid from the non-aqueous absorption liquid. The process mitigates absorbent degradation problems caused by sulphur dioxide and oxygen in flue gas.

Isocratic non-aqueous reversed-phase high-performance liquid chromatographic separation of capsanthin and capsorubin in red peppers (Capsicum annuum L.), paprika and oleoresin.

PubMed

Weissenberg, M; Schaeffler, I; Menagem, E; Barzilai, M; Levy, A

1997-01-03

A simple, rapid high-performance liquid chromatography method has been devised in order to separate and quantify the xanthophylls capsorubin and capasanthin present in red pepper (Capsicum annuum L.) fruits and preparations made from them (paprika and oleoresin). A reversed-phase isocratic non-aqueous system allows the separation of xanthophylls within a few minutes, with detection at 450 nm, using methyl red as internal standard to locate the various carotenoids and xanthophylls found in plant extracts. The selection of extraction solvents, mild saponification conditions, and chromatographic features is evaluated and discussed. The method is proposed for rapid screening of large plant populations, plant selection, as well as for paprika products and oleoresin, and also for nutrition and quality control studies.

Detecting and characterizing ice units with the WISDOM Radar

NASA Astrophysics Data System (ADS)

Ciarletti, V.; Plettemeier, D.; Dorizon, S.; Clifford, S. M.; Biancheri-Astier, M.; Dechambre, M.; Saintenoy, A. C.; Costard, F.

2012-12-01

The WISDOM (Water Ice Subsurface Deposit Observation on Mars) Ground Penetrating Radar (GPR) is one of the instruments that have been selected as part of the Pasteur payload of ESA's 2018 ExoMars Rover mission. WISDOM main objectives are to understand the geology and evolution of the landing site and to help identifying locations in the shallow subsurface where organic molecules are the most likely to be found and well-preserved. In the context of the ExoMars mission, the importance of the WISDOM GPR is particularly enhanced by its ability to investigate the distribution and state of subsurface water - both as a liquid and as ice. For example, within the diurnally active thermal layer of the subsurface (i.e., the top ~15 - 25 cm), the transient melting and freezing of subsurface ice and brine may be detectable by comparing day- and night-time radar observations at the same location. Moreover, while the biological significance of liquid water on Mars is obvious, a more readily accessible and enduring record of biological activity may be organic biomarkers preserved in subsurface ice. Unfortunately, the dielectric contrast between rock, soil and ice is small, and therefore, differentiating between mixtures of ice-rich and ice-poor regolith in the Martian subsurface is an extraordinarily difficult task. Preliminary tests in both natural (glacier in the Alps and caves in Austria) and artificial (cold chamber) icy environments have been performed with a prototype representative of the WISDOM instrument flight model. These investigations have demonstrated WISDOM's ability to detect and characterize subsurface ice in various forms. Specific examples will be discussed that demonstrate the instrument's depth of sounding, dielectric sensitivity, spatial resolution, full polarimetric and 3-D capability.

Gold sputtered Blu-Ray disks as novel and cost effective sensors for surface enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Nieuwoudt, Michél. K.; Martin, Jacob W.; Oosterbeek, Reece N.; Novikova, Nina I.; Wang, Xindi; Malmström, Jenny; Williams, David E.; Simpson, M. C.

2015-03-01

Surface Enhanced Raman spectroscopy (SERS) offers sensitive and non-invasive detection of a variety of compounds as well as unparalleled information for establishing the molecular identity of both inorganic and organic compounds, not only in biological fluids but in all other aqueous and non-aqueous media. The localized hotspots produced through SERS at the solution/nanostructure interface of clustered gold or silver nano-particles enables detection levels of parts per trillion. Recent developments in advanced fabrication methods have enabled the manufacture of SERS substrates with repeatable surface nanostructures which provide reproducible quantitative analysis, historically a weakness of the SERS technique. In this paper we describe the novel use of gold sputtered Blu-Ray surfaces as SERS substrates. Blu-Ray disks provide ideal surfaces of SERS substrates with their repeatable and regular nano-gratings. We show that the unique surface features and composition of the recording surface enables the formation of gold nano-islands with nanogaps, simply through gold sputtering, and relate this to a 600 fold signal increase of the melamine Raman signal in aqueous solutions and detection to 68 ppb. Melamine is a triazine compound and appears not only as environmental contaminant in environmental groundwater but also as an adulterant in foods due to its high nitrogen content. We have shown significant SERS signal enhancements for spectra of melamine using gold-sputtered Blu-Ray disk surfaces, with reproducibility of 12%. Blu-Ray disks have a unique combination of design, surface features and composition of the recording surface which makes them ideal for preparation of SERS substrates by gold sputter-coating.

Phenyl boron-based compounds as anion receptors for non-aqueous battery electrolytes

DOEpatents

Lee, Hung Sui; Yang, Xiao-Qing; McBreen, James; Sun, Xuehui

2002-01-01

Novel fluorinated boronate-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boronate-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boronate-based anion receptors include different fluorinated alkyl and aryl groups.

Effect of flow velocity on the photoacoustic detection for glucose aqueous solutions

NASA Astrophysics Data System (ADS)

Ren, Zhong; Liu, Guodong; Ding, Yu; Yao, Qingkai

2018-01-01

The blood glucose non-invasive detection has become the research hot-spot. The photoacoustic spectroscopy is a well-promising, high-efficient and noninvasive detection method because it combines the advantages of the pure optic and pure ultrasonic. In practice, the photoacoustic detection of blood glucose is impacted by many factors because the human body is a complicated bio-system. To study the effect of flow velocity in the blood vessel on the photoacoustic detection of blood glucose, a photoacoustic detection system based on optical parameter oscillator (OPO) pulsed laser induced ultrasonic was established. In this system, a 532nm pumped Nd: YAG OPO pulsed laser was used as the excitation source, and the photoacoustic signals of glucose were captured by ultrasonic transducer. Moreover, a set of blood circulation system was built to simulate the real blood flow situation in the human body. The experiments of the photoacoustic detection of glucose aqueous solutions with different concentrations at different flow velocities were experimentally investigated. Experimental results show that the photoacoustic peak-to-peak value linearly increases with the glucose concentration, but it decreases with the increase of the flow velocity although the profiles of photoacoustic signals don't change.

Non-Psychrophilic Methanogens Capable of Growth Following Long-Term Extreme Temperature Changes, with Application to Mars.

PubMed

Mickol, Rebecca L; Laird, Sarah K; Kral, Timothy A

2018-04-23

Although the martian environment is currently cold and dry, geomorphological features on the surface of the planet indicate relatively recent (<4 My) freeze/thaw episodes. Additionally, the recent detections of near-subsurface ice as well as hydrated salts within recurring slope lineae suggest potentially habitable micro-environments within the martian subsurface. On Earth, microbial communities are often active at sub-freezing temperatures within permafrost, especially within the active layer, which experiences large ranges in temperature. With warming global temperatures, the effect of thawing permafrost communities on the release of greenhouse gases such as carbon dioxide and methane becomes increasingly important. Studies examining the community structure and activity of microbial permafrost communities on Earth can also be related to martian permafrost environments, should life have developed on the planet. Here, two non-psychrophilic methanogens, Methanobacterium formicicum and Methanothermobacter wolfeii , were tested for their ability to survive long-term (~4 year) exposure to freeze/thaw cycles varying in both temperature and duration, with implications both for climate change on Earth and possible life on Mars.

Huygens Crater: Insights into Noachian Volcanism, Stratigraphy, and Aqueous Processes

NASA Technical Reports Server (NTRS)

Ackiss, S. E.; Wray, J. J.; Seelos, K. D.; Niles, P. B.

2015-01-01

Huygens crater is a well preserved peak ring structure on Mars centered at 13.5 deg S, 55.5 deg E in the Noachian highlands between Terras Tyrrhena and Sabaea near the NW rim of Hellas basin. With a diameter of approximately 470 km, it uplifted and exhumed pre-Noachian crustal materials from depths greater than 25 km, penetrating below the thick, ubiquitous layer of Hellas ejecta. In addition, Huygens served as a basin for subsequent aqueous activity, including erosion/deposition by fluvial valley networks and subsurface alteration that is now exposed by smaller impacts. Younger mafic-bearing plains that partially cover the basin floor and surrounding intercrater areas were likely emplaced by later volcanism.

Unraveling the Diversity of Early Aqueous Environments and Climate on Mars Through the Phyllosilicate Record

NASA Technical Reports Server (NTRS)

Bishop, J. L.; Baker, L. L.; Fairén, A. G.; Gross, C.; Velbel, M. A.; Rampe, E. B.; Michalski, J. R.

2017-01-01

Were Martian phyllosilicates formed on the surface or subsurface? Was early Mars warm or cold? How long was liquid water present on the surface of Mars? These are some of the many open questions about our neighboring planet. We propose that the mineralogy of the clay-bearing outcrops on Mars can help address these questions. Abundant phyllosilicates and aqueous minerals are observed nearly everywhere we can see the ancient rocks on Mars. Most bountiful among these is Fe/Mg-smectite. In this study we evaluate the nature and stratigraphy of clay outcrops observed on Mars and the presence of mixtures of other clays or other minerals with the ubiquitous Fe/Mg-smectite.

CO2 Driven Mineral Transformations in Fractured Reservoir

NASA Astrophysics Data System (ADS)

Schaef, T.

2015-12-01

Engineering fracture systems in low permeable formations to increase energy production, accelerate heat extraction, or to enhance injectivity for storing anthropogenic CO2, is a challenging endeavor. To complicate matters, caprocks, essential components of subsurface reservoirs, need to maintain their sealing integrity in this modified subsurface system. Supercritical CO2 (scCO2), a proposed non-aqueous based working fluid, is capable of driving mineral transformations in fracture environments. Water dissolution in scCO2 significantly impacts the reactivity of this fluid, largely due to the development of thin adsorbed H2O films on the surfaces of exposed rocks and minerals. Adsorbed H2O films are geochemically complex microenvironments that host mineral dissolution and precipitation processes that could be tailored to influence overall formation permeability. Furthermore, manipulating the composition of injected CO2 (e.g., moisture content and/or reactive gases such as O2, NOx, or SOx) could stimulate targeted mineral transformations that enhance or sustain reservoir performance. PNNL has developed specialized experimental techniques that can be used to characterize chemical reactions occurring between minerals and pressurized gases. For example, hydration of a natural shale sample (Woodford Shale) has been characterized by an in situ infrared spectroscopic technique as water partitions from the scCO2 onto the shale. Mineral dissolution and carbonate precipitation reactions were tracked by monitoring changes of Si-O and C-O stretching bands, respectively Structural changes indicated expandable clays in the shale such as montmorillonite are intercalated with scCO2, a process not observed with the non-expandable kaolinite component. Extreme scale ab initio molecular dynamics simulations were used in conjunction with model mineral systems to identify the driving force and mechanism of water films. They showed that the film nucleation and formation on minerals is driven by both enthalpic and entropic requirements. Collectively, the synergy between laboratory observations, state-of-the-art atomistic simulations and reservoir modeling has generated important insights for the design and engineering of subsurface reservoirs for CO2 storage and energy extraction.

A STUDY TO DETERMINE THE FEASIBILITY OF USING A GROUND-PENETRATING RADAR FOR MORE EFFECTIVE REMEDIATION OF SUBSURFACE CONTAMINATION

EPA Science Inventory

A study was conducted (1) to assess the capability of groundpenetrating radar (GPR) to identify natural subsurface features, detect man-made objects burled in the soil, and both detect and define the extent of contaminated soil or ground water due to a toxic spill, and (2) to det...

Lithium1.3Aluminum0.3Titanium1.7Phosphate as a solid state Li-ion conductor: Issues with microcracking and stability in aqueous solutions

NASA Astrophysics Data System (ADS)

Jackman, Spencer D.

Lithium aluminum titanium phosphate (LATP) with formula Li1.3Al0.3Ti1.7(PO4)3 was analyzed and tested to better understand its applicability as a solid state ion conducting ceramic material for electrochemical applications. Sintered samples were obtained from Ceramatec, Inc. in Salt Lake City and characterized in terms of density, phase-purity, fracture toughness, Young's modulus, thermal expansion behavior, mechanical strength, a.c. and d.c. ionic conductivity, and susceptibility to static and electrochemical corrosion in aqueous Li salt solutions. It was shown that LATP is prone to microcrack generation because of high thermal expansion anisotropy. A.c. impedance spectra of high-purity LATP of varying grain sizes showed that microcracking had a negative impact on the ionic conduction of Li along grain boundaries, with fine-grained (1.7±0.7 µm) LATP having twice the ionic conductivity of the same purity of coarse-grained (4.8±1.9 µm) LATP at 50°C. LATP with detectible secondary phases had lower ionic conductivity for similar grain sizes, as would be expected. The Young's modulus of fine-grained LATP was measured to be 115 GPa, and the highest biaxial strength was 191±11 MPa when tested in mineral oil, 144±13 MPa as measured in air, and 26±7 MPa after exposure to deionized water, suggesting that LATP undergoes stress-corrosion cracking. After exposure to LiOH, the strength was 76±19 MPa. This decrease in strength was observed despite there being no measureable change in a.c. impedance spectra, X-ray diffraction, or sample mass, suggesting phosphate glasses at grain boundaries. The chemical and electrochemical stability of high-purity LATP in aqueous electrochemical cells was evaluated using LiOH, LiCl, LiNO3, and LiCOOCH3 salts as the Li source. LATP was found to be most stable between pH 8-9, with the longest cell operating continuously at 25 mA cm-2 for 625 hours at 40°C in LiCOOCH3. At pH values outside of the 7-10 range, eventual membrane degradation was observed in all aqueous systems under electrochemical conditions. While LATP was surprisingly resistant to static corrosion in a hot, aqueous LiOH solution, electrochemical degradation was observed at the cathode due to subsurface pitting. Strength measurements were more instructive than impedance measurements in detecting this degradation.

Imaging Pancreatic Cancer Using Bioconjugated InP Quantum Dots

PubMed Central

Yong, Ken-Tye; Ding, Hong; Roy, Indrajit; Law, Wing-Cheung; Bergey, Earl J.; Maitra, Anirban; Prasad, Paras N.

2009-01-01

In this paper, we report the successful use of non-cadmium based quantum dots (QDs) as highly efficient and non-toxic optical probes for imaging live pancreatic cancer cells. Indium phosphide (core)-zinc sulphide (shell), or InP/ZnS, QDs with high quality and bright luminescence were prepared by a hot colloidal synthesis method in non-aqueous media. The surfaces of these QDs were then functionalized with mercaptosuccinic acid to make them highly dispersible in aqueous media. Further bioconjugation with pancreatic cancer specific monoclonal antibodies, such as anti-claudin 4 and anti-prostate stem cell antigen (anti-PSCA), to the functionalized InP/ZnS QDs, allowed specific in vitro targeting of pancreatic cancer cell lines (both immortalized and low passage ones). The receptor mediated delivery of the bioconjugates was further confirmed by the observation of poor in vitro targeting in non-pancreatic cancer based cell lines which are negative for the claudin-4-receptor. These observations suggest the immense potential of InP/ZnS QDs as non-cadmium based safe and efficient optical imaging nanoprobes in diagnostic imaging, particularly for early detection of cancer. PMID:19243145

Integration of airborne optical and thermal imagery for archaeological subsurface structures detection: the Arpi case study (Italy)

NASA Astrophysics Data System (ADS)

Bassani, C.; Cavalli, R. M.; Fasulli, L.; Palombo, A.; Pascucci, S.; Santini, F.; Pignatti, S.

2009-04-01

The application of Remote Sensing data for detecting subsurface structures is becoming a remarkable tool for the archaeological observations to be combined with the near surface geophysics [1, 2]. As matter of fact, different satellite and airborne sensors have been used for archaeological applications, such as the identification of spectral anomalies (i.e. marks) related to the buried remnants within archaeological sites, and the management and protection of archaeological sites [3, 5]. The dominant factors that affect the spectral detectability of marks related to manmade archaeological structures are: (1) the spectral contrast between the target and background materials, (2) the proportion of the target on the surface (relative to the background), (3) the imaging system characteristics being used (i.e. bands, instrument noise and pixel size), and (4) the conditions under which the surface is being imaged (i.e. illumination and atmospheric conditions) [4]. In this context, just few airborne hyperspectral sensors were applied for cultural heritage studies, among them the AVIRIS (Airborne Visible/Infrared Imaging Spectrometer), the CASI (Compact Airborne Spectrographic Imager), the HyMAP (Hyperspectral MAPping) and the MIVIS (Multispectral Infrared and Visible Imaging Spectrometer). Therefore, the application of high spatial/spectral resolution imagery arise the question on which is the trade off between high spectral and spatial resolution imagery for archaeological applications and which spectral region is optimal for the detection of subsurface structures. This paper points out the most suitable spectral information useful to evaluate the image capability in terms of spectral anomaly detection of subsurface archaeological structures in different land cover contexts. In this study, we assess the capability of MIVIS and CASI reflectances and of ATM and MIVIS emissivities (Table 1) for subsurface archaeological prospection in different sites of the Arpi archaeological area (southern Italy). We identify, for the selected sites, three main land cover overlying the buried structures: (a) photosynthetic (i.e. green low vegetation), (b) non-photosynthetic vegetation (i.e. yellow, dry low vegetation), and (c) dry bare soil. Afterwards, we analyse the spectral regions showing an inherent potential for the archaeological detection as a function of the land cover characteristics. The classified land cover units have been used in a spectral mixture analysis to assess the land cover fractional abundance surfacing the buried structures (i.e. mark-background system). The classification and unmixing results for the CASI, MIVIS and ATM remote sensing data processing showed a good accordance both in the land cover units and in the subsurface structures identification. The integrated analysis of the unmixing results for the three sensors allowed us to establish that for the land cover characterized by green and dry vegetation (occurrence higher than 75%), the visible and near infrared (VNIR) spectral regions better enhance the buried man-made structures. In particular, if the structures are covered by more than 75% of vegetation the two most promising wavelengths for their detection are the chlorophyll peak at 0.56 m (Visible region) and the red edge region (0.67 to 0.72 m; NIR region). This result confirms that the variation induced by the subsurface structures (e.g., stone walls, tile concentrations, pavements near the surface, road networks) to the natural vegetation growth and/or colour (i.e., for different stress factors) is primarily detectable by the chlorophyll peak and the red edge region applied for the vegetation stress detection. Whereas, if dry soils cover the structures (occurrence higher than 75%), both the VNIR and thermal infrared (TIR) regions are suitable to detect the subsurface structures. This work demonstrates that airborne reflectances and emissivities data, even though at different spatial/spectral resolutions and acquisition time represent an effective and rapid tool to detect subsurface structures within different land cover contexts. As concluding results, this study reveals that the airborne multi/hyperspectral image processing can be an effective and cost-efficient tool to perform a preliminary analysis of those areas where large cultural heritage assets prioritising and localizing the sites where to apply near surface geophysics surveys. Spectral Region Spectral Resolution ( m )Spectral Range ( m) Spatial Resolution (m)IFOV (deg) ATM VIS-NIR SWIR-TIR (tot 12 ch) variable from 24 to 3100 0.42 - 1150 2 0.143 CASI VNIR (48 ch.) 0.01 0.40-0.94 2 0.115 MIVIS VNIR (28ch.) 0.02 (VIS) 0.05 (NIR) 0.43-0.83 (VIS) 1.15-1.55 (NIR) 6 - 7 0.115 SWIR (64ch.) 0.09 1.983-2.478 TIR (10ch.) 0.34-0.54 8.180-12.700 Table 1. Characteristics of airborne sensors used for the Arpi test area. 1 References 2 [1] Beck, A., Philip, G., Abdulkarim, M. and Donoghue, D., 2007. Evaluation of Corona and Ikonos high resolution satellite imagery for archaeological prospection in western Syria. Antiquity, 81: 161-175. 3 [2] Altaweel, M., 2005. The Use of ASTER Satellite Imagery in Archaeological Contexts. Archaeological Prospection, 12: 151- 166. 4 [3] Cavalli, R.M.; Colosi, F.; Palombo, A.; Pignatti, S.; Poscolieri, M. Remote hyperspectral imagery as a support to archaeological prospection. J. of Cultural Heritage 2007, 8, 272-283. 5 [4] Kucukkaya, A.G. Photogrammetry and remote sensing in archaeology. J. Quant. Spectrosc. Radiat. Transfer 2004, 97(1-3), 83-97. [5] Rowlands, A.; Sarris, A. Detection of exposed and subsurface archaeological remains using multi-sensor remote sensing. J. of Archaeological Science 2007, 34, 795-803.

Detection of Noble Gas Radionuclides from an Underground Nuclear Explosion During a CTBT On-Site Inspection

NASA Astrophysics Data System (ADS)

Carrigan, Charles R.; Sun, Yunwei

2014-03-01

The development of a technically sound approach to detecting the subsurface release of noble gas radionuclides is a critical component of the on-site inspection (OSI) protocol under the Comprehensive Nuclear Test Ban Treaty. In this context, we are investigating a variety of technical challenges that have a significant bearing on policy development and technical guidance regarding the detection of noble gases and the creation of a technically justifiable OSI concept of operation. The work focuses on optimizing the ability to capture radioactive noble gases subject to the constraints of possible OSI scenarios. This focus results from recognizing the difficulty of detecting gas releases in geologic environments—a lesson we learned previously from the non-proliferation experiment (NPE). Most of our evaluations of a sampling or transport issue necessarily involve computer simulations. This is partly due to the lack of OSI-relevant field data, such as that provided by the NPE, and partly a result of the ability of computer-based models to test a range of geologic and atmospheric scenarios far beyond what could ever be studied by field experiments, making this approach very highly cost effective. We review some highlights of the transport and sampling issues we have investigated and complete the discussion of these issues with a description of a preliminary design for subsurface sampling that addresses some of the sampling challenges discussed here.

Low frequency acoustic microscope

DOEpatents

Khuri-Yakub, Butrus T.

1986-11-04

A scanning acoustic microscope is disclosed for the detection and location of near surface flaws, inclusions or voids in a solid sample material. A focused beam of acoustic energy is directed at the sample with its focal plane at the subsurface flaw, inclusion or void location. The sample is scanned with the beam. Detected acoustic energy specularly reflected and mode converted at the surface of the sample and acoustic energy reflected by subsurface flaws, inclusions or voids at the focal plane are used for generating an interference signal which is processed and forms a signal indicative of the subsurface flaws, inclusions or voids.

Formation of liquid water at low temperatures via the deliquescence of calcium chloride: Implications for Antarctica and Mars

NASA Astrophysics Data System (ADS)

Gough, R. V.; Chevrier, V. F.; Tolbert, M. A.

2016-10-01

There is significant interest in the potential existence of even small amounts of liquid brine on current Mars. It has been proposed that aqueous solutions could form on Mars via the deliquescence of hygroscopic salts in contact with atmospheric water vapor, and these hygroscopic salts have recently been detected in recurring slope linae (RSL). While past work has largely focused on perchlorate species, another Mars-relevant salt that has a low eutectic temperature and may be deliquescent is calcium chloride, CaCl2. This salt may be linked to RSL formation on Mars, and deliquescence of CaCl2 is also known to be responsible for the only terrestrial RSL analog features known thus far: water tracks in the McMurdo Dry Valleys. Here we use Raman microscopy to monitor the low-temperature (223-273 K) deliquescence (solid to aqueous phase transition) and efflorescence (aqueous to solid phase transition) of two hydration states of CaCl2, the dihydrate and the hexahydrate. We find the deliquescence relative humidity (DRH) decreases with decreasing hydration state and with increasing temperature. Average DRH values over the temperature range studied are 15.8±3.5% RH for the dihydrate and 63.3±12.5% RH for the hexahydrate, making this salt at least as deliquescent as many perchlorate salts. A remarkable property of CaCl2 is its ability to persist as metastable, supersaturated brine. Once an aqueous solution was formed, efflorescence (recrystallization) of the liquid did not occur until single-digit RH values were reached (3.9±2.4% RH on average). We show that temperature and relative humidity conditions in the martian subsurface are sufficient to allow deliquescence of CaCl2, and the resulting brines may persist for over half of a martian sol. Therefore, this salt could play a role in RSL formation, the martian water cycle, and have implications for the potential habitability of Mars.

Enhanced truncated-correlation photothermal coherence tomography with application to deep subsurface defect imaging and 3-dimensional reconstructions

NASA Astrophysics Data System (ADS)

Tavakolian, Pantea; Sivagurunathan, Koneswaran; Mandelis, Andreas

2017-07-01

Photothermal diffusion-wave imaging is a promising technique for non-destructive evaluation and medical applications. Several diffusion-wave techniques have been developed to produce depth-resolved planar images of solids and to overcome imaging depth and image blurring limitations imposed by the physics of parabolic diffusion waves. Truncated-Correlation Photothermal Coherence Tomography (TC-PCT) is the most successful class of these methodologies to-date providing 3-D subsurface visualization with maximum depth penetration and high axial and lateral resolution. To extend the depth range and axial and lateral resolution, an in-depth analysis of TC-PCT, a novel imaging system with improved instrumentation, and an optimized reconstruction algorithm over the original TC-PCT technique is developed. Thermal waves produced by a laser chirped pulsed heat source in a finite thickness solid and the image reconstruction algorithm are investigated from the theoretical point of view. 3-D visualization of subsurface defects utilizing the new TC-PCT system is reported. The results demonstrate that this method is able to detect subsurface defects at the depth range of ˜4 mm in a steel sample, which exhibits dynamic range improvement by a factor of 2.6 compared to the original TC-PCT. This depth does not represent the upper limit of the enhanced TC-PCT. Lateral resolution in the steel sample was measured to be ˜31 μm.

Biofilm-induced calcium carbonate precipitation: application in the subsurface

NASA Astrophysics Data System (ADS)

Phillips, A. J.; Eldring, J.; Lauchnor, E.; Hiebert, R.; Gerlach, R.; Mitchell, A. C.; Esposito, R.; Cunningham, A. B.; Spangler, L.

2012-12-01

We have investigated mitigation strategies for sealing high permeability regions, like fractures, in the subsurface. This technology has the potential to, for example, improve the long-term security of geologically-stored carbon dioxide (CO2) by sealing fractures in cap rocks or to mitigate leakage pathways to prevent contamination of overlying aquifers from hydraulic fracturing fluids. Sealing technologies using low-viscosity fluids are advantageous since they potentially reduce the necessary injection pressures and increase the radius of influence around injection wells. In this technology, aqueous solutions and suspensions are used to promote microbially-induced mineral precipitation which can be applied in subsurface environments. To this end, a strategy was developed to twice seal a hydraulically fractured, 74 cm (2.4') diameter Boyles Sandstone core, collected in North-Central Alabama, with biofilm-induced calcium carbonate (CaCO3) precipitates under ambient pressures. Sporosarcina pasteurii biofilms were established and calcium and urea containing reagents were injected to promote saturation conditions favorable for CaCO3 precipitation followed by growth reagents to resuscitate the biofilm's ureolytic activity. Then, in order to evaluate this process at relevant deep subsurface pressures, a novel high pressure test vessel was developed to house the 74 cm diameter core under pressures as high as 96 bar (1,400 psi). After determining that no impact to the fracture permeability occurred due to increasing overburden pressure, the fractured core was sealed under subsurface relevant pressures relating to 457 meters (1,500 feet) below ground surface (44 bar (650 psi) overburden pressure). After fracture sealing under both ambient and subsurface relevant pressure conditions, the sandstone core withstood three times higher well bore pressure than during the initial fracturing event, which occurred prior to biofilm-induced CaCO3 mineralization. These studies suggest biofilm-induced CaCO3 precipitation technologies may potentially seal and strengthen high permeability regions or fractures (either natural or induced) in the subsurface. Novel high pressure test vessel to investigate biogeochemical processes under relevant subsurface scales and pressures.

Wellhead with non-ferromagnetic materials

DOEpatents

Hinson, Richard A [Houston, TX; Vinegar, Harold J [Bellaire, TX

2009-05-19

Wellheads for coupling to a heater located in a wellbore in a subsurface formation are described herein. At least one wellhead may include a heater located in a wellbore in a subsurface formation; and a wellhead coupled to the heater. The wellhead may be configured to electrically couple the heater to one or more surface electrical components. The wellhead may include at least one non-ferromagnetic material such that ferromagnetic effects are inhibited in the wellhead. Systems and methods for using such wellheads for treating a subsurface formation are described herein.

Searching for Life in the Martian Subsurface: Results from the MARTE Astrobiological Drilling Experiment and Implications for Future Missions

NASA Astrophysics Data System (ADS)

Stoker, C. R.

2007-07-01

Drilling for subsurface life should be a goal of future Mars missions. The approach is illustrated by MARTE: A search for subsurface life in Rio Tinto, Spain explored a biosphere using reduced iron and sulfur minerals and demonstrated automated drilling, sample handling, and life detection.

Non-interferometric deep optical resolution photoacoustic remote sensing microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

HajiReza, Parsin H.; Bell, Kevan L.; Shi, Wei; Zemp, Roger J.

2017-03-01

A novel all-optical non-contact photoacoustic microscopy system is introduced. The confocal configuration is used to ensure detection of initial pressure shock wave-induced intensity reflections at the subsurface origin where pressures are largest. Phantom studies confirm signal dependence on optical absorption, index-contrast, and excitation fluence. Taking advantage of a focused1310 nm interrogation beam, the penetration depth of the system is improved to 2mm for an optical resolution system. High signal-to-noise ratios (>60dB) with 2.5 cm working distance from the objective lens to the sample is achieved. Real-time in-vivo imaging of microvasculature and melanoma tumors are demonstrated.

Detection in subsurface air of radioxenon released from medical isotope production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Christine; Biegalski, Steven; Haas, Derek

Abstract Under the Comprehensive Nuclear-Test-Ban Treaty, an On-Site Inspection (OSI) may be conducted to clarify whether a nuclear explosion has been carried out in violation of Article I of the Treaty. A major component of an OSI is the measurement of subsurface gases in order to detect radioactive noble gases that are produced in a nuclear explosion, particularly radioxenon and radioargon. In order to better understand potential backgrounds of these gases, a sampling campaign was performed near Canadian Nuclear Laboratories in the Ottawa River Valley, a major source of environmental radioxenon. First of their kind measurements of atmospheric radioxenon imprintedmore » into the shallow subsurface from an atmospheric pressure driven force were made using current OSI techniques to measure both atmospheric and subsurface gas samples which were analyzed for radioxenon. These measurements indicate that under specific sampling conditions, on the order of one percent of the atmospheric radioxenon concentration may be measured via subsurface sampling.« less

Aqueous alteration revealed by diverse mineralogy at Amazonian-aged Lyot crater, Mars

NASA Astrophysics Data System (ADS)

Pan, L.; Ehlmann, B. L.

2016-12-01

Located close to the hemispheric dichotomy, Lyot crater is the largest (with diameter 220 km) and deepest impact crater in the northern lowlands of Mars. The impact event could have released substantial amount of volatiles and strongly influenced the evolution of Amazonian Mars climate [1]. Previous works have shown that the impact event probably induced overland flow that formed the channels north of Lyot [2] and within the crater, kilometer-long valleys have formed in micro-environments that post-date the impact [3]. These features suggest that groundwater may have been mobilized in the subsurface, and there was melting of ice-rich deposits after the impact event. In a recent mineralogy survey [4], diverse hydrated minerals in and around Lyot crater have been revealed by data acquired from Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). The concentration of hydrated minerals in this region is much greater than average northern plains, suggesting substantial aqueous alteration directly associated to the Lyot impact or in the regional stratigraphy. We have found 7 Fe/Mg phyllosilicate detections, likely smectite or mixed-layer smectite-chlorite, in the central ring region; 10 chlorite/prehnite detections (identified with a typical 2.35 µm absorption, in which 2 have an additional 1.48 µm absorption that matches prehnite, confirming [5]) in the central ring, crater floor, outer rim, and ejecta blanket; and 9 locations with absorptions at 2.21 µm with/without the coexistence with the 2.35 µm feature, which can be explained by illite/muscovite or a mixture of hydrated silica and chlorite/prehnite. The unit with 2.21-µm absorptions is often associated with the smooth mantling deposit, superposed on the valleys within the crater and on the crater rim. Further morphological analysis over these units with distinct mineralogy will shed light on the aqueous activity that formed these minerals. Combined with geological map of the region, we will establish the timeline of aqueous activities associated with the impact and provide insights into the climatic influence of Lyot impact in the Amazonian age. [1] Toon et al. (2010) Ann. Rev Earth Plan. Sci 38 [2] Harrison et al. (2010) GRL 37(21) [3] Dickson et al. (2010) GRL 36(8) [4] Pan, Ehlmann, Carter, Ernst, JGR Planets, submitted [5] Carter et al., (2010) Science.

Rapid One-step Enzymatic Synthesis and All-aqueous Purification of Trehalose Analogues.

PubMed

Meints, Lisa M; Poston, Anne W; Piligian, Brent F; Olson, Claire D; Badger, Katherine S; Woodruff, Peter J; Swarts, Benjamin M

2017-02-17

Chemically modified versions of trehalose, or trehalose analogues, have applications in biology, biotechnology, and pharmaceutical science, among other fields. For instance, trehalose analogues bearing detectable tags have been used to detect Mycobacterium tuberculosis and may have applications as tuberculosis diagnostic imaging agents. Hydrolytically stable versions of trehalose are also being pursued due to their potential for use as non-caloric sweeteners and bioprotective agents. Despite the appeal of this class of compounds for various applications, their potential remains unfulfilled due to the lack of a robust route for their production. Here, we report a detailed protocol for the rapid and efficient one-step biocatalytic synthesis of trehalose analogues that bypasses the problems associated with chemical synthesis. By utilizing the thermostable trehalose synthase (TreT) enzyme from Thermoproteus tenax, trehalose analogues can be generated in a single step from glucose analogues and uridine diphosphate glucose in high yield (up to quantitative conversion) in 15-60 min. A simple and rapid non-chromatographic purification protocol, which consists of spin dialysis and ion exchange, can deliver many trehalose analogues of known concentration in aqueous solution in as little as 45 min. In cases where unreacted glucose analogue still remains, chromatographic purification of the trehalose analogue product can be performed. Overall, this method provides a "green" biocatalytic platform for the expedited synthesis and purification of trehalose analogues that is efficient and accessible to non-chemists. To exemplify the applicability of this method, we describe a protocol for the synthesis, all-aqueous purification, and administration of a trehalose-based click chemistry probe to mycobacteria, all of which took less than 1 hour and enabled fluorescence detection of mycobacteria. In the future, we envision that, among other applications, this protocol may be applied to the rapid synthesis of trehalose-based probes for tuberculosis diagnostics. For instance, short-lived radionuclide-modified trehalose analogues (e.g., 18 F-modified trehalose) could be used for advanced clinical imaging modalities such as positron emission tomography-computed tomography (PET-CT).

Force measurement-based discontinuity detection during friction stir welding

DOE PAGES

Shrivastava, Amber; Zinn, Michael; Duffie, Neil A.; ...

2017-02-23

Here, the objective of this work is to develop a method for detecting the creation of discontinuities ( i.e., voids, volume defects) during friction stir welding. Friction stir welding is inherently cost effective, however, the need for significant weld inspection can make the process cost prohibitive. A new approach to weld inspection is required in which an in situ characterization of weld quality can be obtained, reducing the need for postprocess inspection. To this end, friction stir welds with subsurface voids and without voids were created. The subsurface voids were generated by reducing the friction stir tool rotation frequency andmore » increasing the tool traverse speed in order to create “colder” welds. Process forces were measured during welding, and the void sizes were measured postprocess by computerized tomography ( i.e., 3D X-ray imaging). Two parameters, based on frequency domain content and time-domain average of the force signals, were found to be correlated with void size. Criteria for subsurface void detection and size prediction were developed and shown to be in good agreement with experimental observations. Furthermore, with the proper choice of data acquisition system and frequency analyzer the occurrence of subsurface voids can be detected in real time.« less

Force measurement-based discontinuity detection during friction stir welding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shrivastava, Amber; Zinn, Michael; Duffie, Neil A.

Here, the objective of this work is to develop a method for detecting the creation of discontinuities ( i.e., voids, volume defects) during friction stir welding. Friction stir welding is inherently cost effective, however, the need for significant weld inspection can make the process cost prohibitive. A new approach to weld inspection is required in which an in situ characterization of weld quality can be obtained, reducing the need for postprocess inspection. To this end, friction stir welds with subsurface voids and without voids were created. The subsurface voids were generated by reducing the friction stir tool rotation frequency andmore » increasing the tool traverse speed in order to create “colder” welds. Process forces were measured during welding, and the void sizes were measured postprocess by computerized tomography ( i.e., 3D X-ray imaging). Two parameters, based on frequency domain content and time-domain average of the force signals, were found to be correlated with void size. Criteria for subsurface void detection and size prediction were developed and shown to be in good agreement with experimental observations. Furthermore, with the proper choice of data acquisition system and frequency analyzer the occurrence of subsurface voids can be detected in real time.« less

Performance of Carbon/Polytetrafluoroethylene (PTFE) Air Cathodes from pH 0 to 14 for Li-Air Batteries

DTIC Science & Technology

2007-12-01

aqueous and aqueous electrolytes are kept separate by a non-electronically conducting ceramic membrane impervious to water, but with a high ionic...thought of as being solvated by the ceramic membrane as it passes from non-aqueous to aqueous electrolyte. The half-cell reaction at the lithium...overall charge in the reaction, positive lithium ions flow through an ionically conducting ceramic membrane from the non-aqueous anode compartment to

Noachian and more recent phyllosilicates in impact craters on Mars

PubMed Central

Fairén, Alberto G.; Chevrier, Vincent; Abramov, Oleg; Marzo, Giuseppe A.; Gavin, Patricia; Davila, Alfonso F.; Tornabene, Livio L.; Bishop, Janice L.; Roush, Ted L.; Gross, Christoph; Kneissl, Thomas; Uceda, Esther R.; Dohm, James M.; Schulze-Makuch, Dirk; Rodríguez, J. Alexis P.; Amils, Ricardo; McKay, Christopher P.

2010-01-01

Hundreds of impact craters on Mars contain diverse phyllosilicates, interpreted as excavation products of preexisting subsurface deposits following impact and crater formation. This has been used to argue that the conditions conducive to phyllosilicate synthesis, which require the presence of abundant and long-lasting liquid water, were only met early in the history of the planet, during the Noachian period (> 3.6 Gy ago), and that aqueous environments were widespread then. Here we test this hypothesis by examining the excavation process of hydrated minerals by impact events on Mars and analyzing the stability of phyllosilicates against the impact-induced thermal shock. To do so, we first compare the infrared spectra of thermally altered phyllosilicates with those of hydrated minerals known to occur in craters on Mars and then analyze the postshock temperatures reached during impact crater excavation. Our results show that phyllosilicates can resist the postshock temperatures almost everywhere in the crater, except under particular conditions in a central area in and near the point of impact. We conclude that most phyllosilicates detected inside impact craters on Mars are consistent with excavated preexisting sediments, supporting the hypothesis of a primeval and long-lasting global aqueous environment. When our analyses are applied to specific impact craters on Mars, we are able to identify both pre- and postimpact phyllosilicates, therefore extending the time of local phyllosilicate synthesis to post-Noachian times. PMID:20616087

Noachian and more recent phyllosilicates in impact craters on Mars.

PubMed

Fairén, Alberto G; Chevrier, Vincent; Abramov, Oleg; Marzo, Giuseppe A; Gavin, Patricia; Davila, Alfonso F; Tornabene, Livio L; Bishop, Janice L; Roush, Ted L; Gross, Christoph; Kneissl, Thomas; Uceda, Esther R; Dohm, James M; Schulze-Makuch, Dirk; Rodríguez, J Alexis P; Amils, Ricardo; McKay, Christopher P

2010-07-06

Hundreds of impact craters on Mars contain diverse phyllosilicates, interpreted as excavation products of preexisting subsurface deposits following impact and crater formation. This has been used to argue that the conditions conducive to phyllosilicate synthesis, which require the presence of abundant and long-lasting liquid water, were only met early in the history of the planet, during the Noachian period (> 3.6 Gy ago), and that aqueous environments were widespread then. Here we test this hypothesis by examining the excavation process of hydrated minerals by impact events on Mars and analyzing the stability of phyllosilicates against the impact-induced thermal shock. To do so, we first compare the infrared spectra of thermally altered phyllosilicates with those of hydrated minerals known to occur in craters on Mars and then analyze the postshock temperatures reached during impact crater excavation. Our results show that phyllosilicates can resist the postshock temperatures almost everywhere in the crater, except under particular conditions in a central area in and near the point of impact. We conclude that most phyllosilicates detected inside impact craters on Mars are consistent with excavated preexisting sediments, supporting the hypothesis of a primeval and long-lasting global aqueous environment. When our analyses are applied to specific impact craters on Mars, we are able to identify both pre- and postimpact phyllosilicates, therefore extending the time of local phyllosilicate synthesis to post-Noachian times.

Subscale Validation of the Subsurface Active Filtration of Exhaust (SAFE) Approach to the NTP Ground Testing

NASA Technical Reports Server (NTRS)

Marshall, William M.; Borowski, Stanley K.; Bulman, Mel; Joyner, Russell; Martin, Charles R.

2015-01-01

Nuclear thermal propulsion (NTP) has been recognized as an enabling technology for missions to Mars and beyond. However, one of the key challenges of developing a nuclear thermal rocket is conducting verification and development tests on the ground. A number of ground test options are presented, with the Sub-surface Active Filtration of Exhaust (SAFE) method identified as a preferred path forward for the NTP program. The SAFE concept utilizes the natural soil characteristics present at the Nevada National Security Site to provide a natural filter for nuclear rocket exhaust during ground testing. A validation method of the SAFE concept is presented, utilizing a non-nuclear sub-scale hydrogen/oxygen rocket seeded with detectible radioisotopes. Additionally, some alternative ground test concepts, based upon the SAFE concept, are presented. Finally, an overview of the ongoing discussions of developing a ground test campaign are presented.

Mastering analytical challenges for the characterization of pentacyclic triterpene mono- and diesters of Calendula officinalis flowers by non-aqueous C30 HPLC and hyphenation with APCI-QTOF-MS.

PubMed

Nicolaus, Christoph; Sievers-Engler, Adrian; Murillo, Renato; D'Ambrosio, Michele; Lämmerhofer, Michael; Merfort, Irmgard

2016-01-25

Pentacyclic triterpene mono- and diesters have been isolated from Calendula officinalis flowers. GC-MS, APCI-Exactive Orbitrap HR-MS and NMR allowed to identify the triterpene skeleton in various samples (different triterpene mixtures from Calendula n-hexane extract). NMR provided evidence that triterpene diesters are present in the samples as well. However, the corresponding quasi-molecular ions could not be detected by APCI-Exactive Orbitrap HR-MS. Instability of triterpene diesters and loss of a fatty acid residue, respectively, in the ion-source made their MS detection challenging. Thus, a set of new APCI-QTOF-MS methods (using the TripleTOF 5600+ mass spectrometer) were developed which made it eventually possible to solve this problem and confirm the diester structures by MS via quasi-molecular ion [M+H](+) detection. Direct infusion APCI-QTOF MS experiments in MS/MS high sensitivity scan mode with low collision energy and multi-channel averaging acquisition (MCA) allowed the detection of quasi-molecular ions of triterpene diesters for the first time and unequivocally confirmed the presence of faradiol 3,16-dimyristate and -dipalmitate, as well as the corresponding mixed diesters faradiol 3-myristate,16-palmitate and faradiol 3-palmitate,16-myristate. Preferential loss of the fatty acid in 16-position made it possible to distinguish the mixed diesters by MS/MS spectra. Their chromatographic separations turned out to be challenging due to their bulkiness and extended molecular dimensions. However, separation could be achieved by an uncommon non-aqueous RPLC mode with an in-house synthesized C30 phase. Finally, two (U)HPLC-APCI-QTOF-MS methods with C18- and C30-based non-aqueous RPLC provided suitable, sensitive assays to monitor the presence of monoesters and diesters of various triterpenes (faradiol, maniladiol, arnidiol, arnitriol A and lupane-3β,16β,20-triol esters) in the n-hexane extract of C. officinalis with high mass resolution and good mass accuracy. Copyright © 2015 Elsevier B.V. All rights reserved.

Planetary science and exploration in the deep subsurface: results from the MINAR Program, Boulby Mine, UK

NASA Astrophysics Data System (ADS)

Payler, Samuel J.; Biddle, Jennifer F.; Coates, Andrew J.; Cousins, Claire R.; Cross, Rachel E.; Cullen, David C.; Downs, Michael T.; Direito, Susana O. L.; Edwards, Thomas; Gray, Amber L.; Genis, Jac; Gunn, Matthew; Hansford, Graeme M.; Harkness, Patrick; Holt, John; Josset, Jean-Luc; Li, Xuan; Lees, David S.; Lim, Darlene S. S.; McHugh, Melissa; McLuckie, David; Meehan, Emma; Paling, Sean M.; Souchon, Audrey; Yeoman, Louise; Cockell, Charles S.

2017-04-01

The subsurface exploration of other planetary bodies can be used to unravel their geological history and assess their habitability. On Mars in particular, present-day habitable conditions may be restricted to the subsurface. Using a deep subsurface mine, we carried out a program of extraterrestrial analog research - MINe Analog Research (MINAR). MINAR aims to carry out the scientific study of the deep subsurface and test instrumentation designed for planetary surface exploration by investigating deep subsurface geology, whilst establishing the potential this technology has to be transferred into the mining industry. An integrated multi-instrument suite was used to investigate samples of representative evaporite minerals from a subsurface Permian evaporite sequence, in particular to assess mineral and elemental variations which provide small-scale regions of enhanced habitability. The instruments used were the Panoramic Camera emulator, Close-Up Imager, Raman spectrometer, Small Planetary Linear Impulse Tool, Ultrasonic drill and handheld X-ray diffraction (XRD). We present science results from the analog research and show that these instruments can be used to investigate in situ the geological context and mineralogical variations of a deep subsurface environment, and thus habitability, from millimetre to metre scales. We also show that these instruments are complementary. For example, the identification of primary evaporite minerals such as NaCl and KCl, which are difficult to detect by portable Raman spectrometers, can be accomplished with XRD. By contrast, Raman is highly effective at locating and detecting mineral inclusions in primary evaporite minerals. MINAR demonstrates the effective use of a deep subsurface environment for planetary instrument development, understanding the habitability of extreme deep subsurface environments on Earth and other planetary bodies, and advancing the use of space technology in economic mining.

Arsenic, microbes and contaminated aquifers

USGS Publications Warehouse

Oremland, Ronald S.; Stolz, John F.

2005-01-01

The health of tens of millions of people world-wide is at risk from drinking arsenic-contaminated well water. In most cases this arsenic occurs naturally within the sub-surface aquifers, rather than being derived from identifiable point sources of pollution. The mobilization of arsenic into the aqueous phase is the first crucial step in a process that eventually leads to human arsenicosis. Increasing evidence suggests that this is a microbiological phenomenon.

Molecular dynamics simulations of uranyl adsorption and structure on the basal surface of muscovite

DOE PAGES

Teich-McGoldrick, Stephanie L.; Greathouse, Jeffery A.; Cygan, Randall T.

2014-02-05

Anthropogenic activities have led to an increased concentration of uranium on the Earth’s surface and potentially in the subsurface with the development of nuclear waste repositories. Uranium is soluble in groundwater, and its mobility is strongly affected by the presence of clay minerals in soils and in subsurface sediments. We use molecular dynamics simulations to probe the adsorption of aqueous uranyl (UO 2 2+) ions onto the basal surface of muscovite, a suitable proxy for typically ultrafine-grained clay phases. Model systems include the competitive adsorption between potassium counterions and aqueous ions (0.1 M and 1.0 M UO 2Cl 2 ,more » 0.1 M NaCl). We find that for systems with potassium and uranyl ions present, potassium ions dominate the adsorption phenomenon. Potassium ions adsorb entirely as inner-sphere complexes associated with the ditrigonal cavity of the basal surface. Uranyl ions adsorb in two configurations when it is the only ion species present, and in a single configuration in the presence of potassium. Finally, the majority of adsorbed uranyl ions are tilted less than 45° relative to the muscovite surface, and are associated with the Si 4Al 2 rings near aluminum substitution sites.« less

Survival in the hot subsurface: Hydrogen stress on hyperthermophilic heterotrophs and methanogens

NASA Astrophysics Data System (ADS)

Topcuoglu, B. D.; Holden, J. F.

2017-12-01

Marine hyperthermophilic heterotrophs and methanogens belonging to the Thermococcales and Methanococcales are often found in hot subsurface environments such as hydrothermal vents, marine sediments, and oil reservoirs. This project aims to make fundamental advances in our understanding of interspecies microbe-microbe interactions in hot subsurface environments by integrating metabolic network modeling, transcriptomic analyses and continuous cultivation of hyperthermophiles and describe how heterotrophs and methanogens eliminate H2 stress. Some subsurface environments may lack alternative electron acceptors (e.g., S°) for the heterotroph and sufficient environmental flux rates to draw in fresh energy sources or remove excess metabolic products. We observed a decrease in growth rates for the H2-producer Thermococcus paralvinellae when grown with an aqueous H2 background of 65 µM relative to no added H2. Metabolite analysis showed increased formate production during H2 inhibition. Differential gene expression analyses coupled with metabolic network modeling showed that T. paralvinellae oxidized H2 and made formate by a formate hydrogenlyase to survive H2 inhibition. Low H2 concentrations (20 µM) also caused a decrease in growth and CH4 production rates for the H2-consuming methanogen Methanocaldococcus jannaschii. H2 stress in both organisms was ameliorated when the organisms were grown together syntrophically. CH4 was produced without any added H2 during syntrophic growth, and there was no formate produced by T. paralvinellae. These organisms may impact the biogeochemistry, especially natural gas production, in saline, organic-rich subsurface environments when both are present.

Effects of Mars Regolith Analogs, UVC radiation, Temperature, Pressure, and pH on the Growth and Survivability of Methanogenic Archaea and Stable Carbon Isotope Fractionation: Implications for Surface and Subsurface Life on Mars

NASA Astrophysics Data System (ADS)

Sinha, Navita

Mars is one of the suitable bodies in our solar system that can accommodate extraterrestrial life. The detection of plumes of methane in the Martian atmosphere, geochemical evidence, indication of flow of intermittent liquid water on the Martian surface, and geomorphologies of Mars have bolstered the plausibility of finding extant or evidence of extinct life on its surface and/or subsurface. However, contemporary Mars has been considered as an inhospitable planet for several reasons, such as low atmospheric surface pressure, low surface temperature, and intense DNA damaging radiation. Despite the hostile conditions of Mars, a few strains of methanogenic archaea have shown survivability in limited surface and subsurface conditions of Mars. Methanogens, which are chemolithoautotrophic non-photosynthetic anaerobic archaea, have been considered ideal models for possible Martian life forms for a long time. The search for biosignatures in the Martian atmosphere and possibility of life on the Martian surface under UVC radiation and deep subsurface under high pressure, temperature, and various pHs are the motivations of this research. Analogous to Earth, Martian atmospheric methane could be biological in origin. Chapter 1 provides relevant information about Mars' habitability, methane on Mars, and different strains of methanogens used in this study. Chapter 2 describes the interpretation of the carbon isotopic data of biogenic methane produced by methanogens grown on various Mars analogs and the results provide clues to determine ambiguous sources of methane on Mars. Chapter 3 illustrates the sensitivity of hydrated and desiccated cultures of halophilic and non-halophilic methanogens to DNA-damaging ultraviolet radiations, and the results imply that UVC radiation may not be an enormous constraint for methanogenic life forms on the surface of Mars. Chapters 4, 5, and 6 discuss the data for the survivability, growth, and morphology of methanogens in presumed deep subsurface physicochemical conditions such as temperature, pressure, hydrogen concentration, and pH of Mars. Finally, chapter 7 provides conclusions, limitations of the experiments, and future perspective of the work. Overall, the quantitative measurements obtained in the various sections of this novel work provide insights to atmospheric biosignatures and survivability of methanogenic organisms on the surface and subsurface of Mars.

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2010 CFR

2010-07-01

... environment and a current awareness file of OSHA regulations regarding the safe handling of the chemicals... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Reverse Phase Extraction (RPE) Method... Part 435 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND...

In situ high temperature microwave microscope for nondestructive detection of surface and sub-surface defects.

PubMed

Wang, Peiyu; Li, Zhencheng; Pei, Yongmao

2018-04-16

An in situ high temperature microwave microscope was built for detecting surface and sub-subsurface structures and defects. This system was heated with a self-designed quartz lamp radiation module, which is capable of heating to 800°C. A line scanning of a metal grating showed a super resolution of 0.5 mm (λ/600) at 1 GHz. In situ scanning detections of surface hole defects on an aluminium plate and a glass fiber reinforced plastic (GFRP) plate were conducted at different high temperatures. A post processing algorithm was proposed to remove the background noises induced by high temperatures and the 3.0 mm-spaced hole defects were clearly resolved. Besides, hexagonal honeycomb lattices were in situ detected and clearly resolved under a 1.0 mm-thick face panel at 20°C and 50°C, respectively. The core wall positions and bonding width were accurately detected and evaluated. In summary, this in situ microwave microscope is feasible and effective in sub-surface detection and super resolution imaging at different high temperatures.

Exploratory studies on some electrochemical cell systems

NASA Astrophysics Data System (ADS)

Chaudhuri, Srikumar; Guha, D.

Exploratory studies were conducted on cell systems with different metal anodes, and iodine and sulphur mixed with graphite powder in a polymer matrix as cathodes, using different electrolytes in non-aqueous and aqueous media as ionic charge carriers. The electrical conductance of the electrolyte solutions in aqueous and non-aqueous solvents, the open circuit voltage (OCV) and short circuit current (SCC) for the different cell systems were measured. To date, the non-aqueous solvents used in our studies were dimethylformamide, formamide, dioxan, and nitrobenzene, and the electrolytes used were potassium iodide, caustic potash, cetyltrimethylammonium bromide (CTAB), sodium lauryl sulphate (SLS) and calcium chloride. These electrolytes were used in both non-aqueous and aqueous media. In general, aqueous electrolyte solutions gave a better performance than non-aqueous electrolyte solutions. Of the aqueous electrolytes, the highest conductance was shown by potassium chloride solution in water (conductance=0.0334 mho). However, the best OCV and SCC were shown by aluminium as anode and iodine as cathode with a saturated solution of caustic potash in water. The OCV was 1.85 V and the SCC was 290 mA cm -2. The highest conductance among the non-aqueous systems was shown by caustic potash in formamide. (Conductance=0.013 mho.) The best OCV and SCC, however, were shown by a zinc anode and iodine cathode with saturated potassium chloride in formamide, having an OCV of 1.55 V and an SCC of 150 mA cm -2. Further studies are in progress to obtain detailed performance data and recharging characteristics of some of the more promising systems reported here.

Assessing the Potential for Ancient Habitable Environments in Gusev Crater, Mars

NASA Astrophysics Data System (ADS)

Des Marais, D. J.; Athena Science Team

2007-12-01

In order to be habitable for microbial life as we know it, an environment must provide nutrient elements, energy and liquid water. We assess the potential for habitable environments in the areas explored by the MER rover Spirit. These areas include the basaltic plains near Columbia Memorial Station, West Spur, Husband Hill, and the inner basin south of Husband Hill. Little aqueous activity apparently occurred in Gusev crater since the basaltic plains were emplaced in Hesperian times, therefore the basaltic plains were highly unlikely to have sustained habitable environments. The Columbia Hills, located ~3 km southeast of the landing site, are older than the surrounding basaltic plains. Aqueous processes have extensively altered bedrock in the Columbia Hills. Ferrous iron in the original, unaltered parent rock of hills materials has typically been oxidized extensively to form ferric oxides, hydroxides, and other ferric minerals. Migrating fluids have removed Ca and other cations, allowing residual Al to become relatively more abundant, and fluids added sulfates and chlorides. In subsurface environments on Earth, microorganisms can obtain key nutrients from the weathering of basalts. Materials examined in the Columbia Hills have comparable or greater abundances of these elements than do MORB. Wishstone rock and Watchtower outcrop have very high contents of phosphorous. Chemoautotrophs ("chemical- feeders" that obtain energy from inorganic chemicals) can thrive in subsurface environments. Mixing oxidized constituents from surface environments with generally more reduced constituents from subsurface rocks and thermal emanations provides energy to sustain microorganisms. Ferrous iron in parent materials in the Columbia Hills has been oxidized to form a variety of ferric minerals. On Earth, microbial processes have been documented to contribute to the production of goethite, hematite and other iron oxides. Observations by Spirit are consistent with the possibility that liquid water, nutrients and sources of chemical energy were simultaneously available to sustain habitable conditions in subsurface Columbia Hills materials at least some time in the distant (Noachian?) past. There is as yet no evidence that these conditions ever existed at the surface. Future research must seek to determine whether ancient migrating fluids in Gusev ever achieved the water activity necessary to sustain life.

A composite numerical model for assessing subsurface transport of oily wastes and chemical constituents

NASA Astrophysics Data System (ADS)

Panday, S.; Wu, Y. S.; Huyakorn, P. S.; Wade, S. C.; Saleem, Z. A.

1997-02-01

Subsurface fate and transport models are utilized to predict concentrations of chemicals leaching from wastes into downgradient receptor wells. The contaminant concentrations in groundwater provide a measure of the risk to human health and the environment. The level of potential risk is currently used by the U.S. Environmental Protection Agency to determine whether management of the wastes should conform to hazardous waste management standards. It is important that the transport and fate of contaminants is simulated realistically. Most models in common use are inappropriate for simulating the migration of wastes containing significant fractions of nonaqueous-phase liquids (NAPLs). The migration of NAPL and its dissolved constituents may not be reliably predicted using conventional aqueous-phase transport simulations. To overcome this deficiency, an efficient and robust regulatory assessment model incorporating multiphase flow and transport in the unsaturated and saturated zones of the subsurface environment has been developed. The proposed composite model takes into account all of the major transport processes including infiltration and ambient flow of NAPL, entrapment of residual NAPL, adsorption, volatilization, degradation, dissolution of chemical constituents, and transport by advection and hydrodynamic dispersion. Conceptually, the subsurface is treated as a composite unsaturated zone-saturated zone system. The composite simulator consists of three major interconnected computational modules representing the following components of the migration pathway: (1) vertical multiphase flow and transport in the unsaturated zone; (2) areal movement of the free-product lens in the saturated zone with vertical equilibrium; and (3) three-dimensional aqueous-phase transport of dissolved chemicals in ambient groundwater. Such a composite model configuration promotes computational efficiency and robustness (desirable for regulatory assessment applications). Two examples are presented to demonstrate the model verification and a site application. Simulation results obtained using the composite modeling approach are compared with a rigorous numerical solution and field observations of crude oil saturations and plume concentrations of total dissolved organic carbon at a spill site in Minnesota, U.S.A. These comparisons demonstrate the ability of the present model to provide realistic depiction of field-scale situations.

Coil design considerations for a high-frequency electromagnetic induction sensing instrument

NASA Astrophysics Data System (ADS)

Sigman, John B.; Barrowes, Benjamin E.; Wang, Yinlin; Bennett, Hollis J.; Simms, Janet E.; Yule, Donald E.; O'Neill, Kevin; Shubitidze, Fridon

2016-05-01

Intermediate electrical conductivity (IEC) materials (101S/m < σ < 104S/m), such as carbon fiber (CF), have recently been used to make smart bombs. In addition, homemade improvised explosive devices (IED) can be produced with low conducting materials (10-4S/m < σ < 1S/m), such as Ammonium Nitrate (AN). To collect unexploded ordnance (UXO) from military training ranges and thwart deadly IEDs, the US military has urgent need for technology capable of detection and identification of subsurface IEC objects. Recent analytical and numerical studies have showed that these targets exhibit characteristic quadrature response peaks at high induction frequencies (100kHz - 15MHz, the High Frequency Electromagnetic Induction (HFEMI) band), and they are not detectable with traditional ultra wideband (UWB) electromagnetic induction (EMI) metal detectors operating between 100Hz - 100kHz. Using the HFEMI band for induction sensing is not so simple as driving existing instruments at higher frequencies, though. At low frequency, EMI systems use more wire turns in transmit and receive coils to boost signal-to-noise ratios (SNR), but at higher frequencies, the transmitter current has non-uniform distribution along the coil length. These non-uniform currents change the spatial distribution of the primary magnetic field and disturb axial symmetry and thwart established approaches for inferring subsurface metallic object properties. This paper discusses engineering tradeoffs for sensing with a broader band of frequencies ever used for EMI sensing, with particular focus on coil geometries.

Subsurface sounders

NASA Technical Reports Server (NTRS)

1975-01-01

Airborne or spaceborne electromagnetic systems used to detect subsurface features are discussed. Data are given as a function of resistivity of ground material, magnetic permeability of free space, and angular frequency. It was noted that resistivities vary with the water content and temperature.

Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Effect of flow configuration and plant species.

PubMed

Chen, Jun; Ying, Guang-Guo; Wei, Xiao-Dong; Liu, You-Sheng; Liu, Shuang-Shuang; Hu, Li-Xin; He, Liang-Ying; Chen, Zhi-Feng; Chen, Fan-Rong; Yang, Yong-Qiang

2016-11-15

This study aims to investigate the removal of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale constructed wetlands (CWs) with different flow configurations or plant species including the constructed wetland with or without plant. Six mesocosm-scale CWs with three flow types (surface flow, horizontal subsurface flow and vertical subsurface flow) and two plant species (Thaliadealbata Fraser and Iris tectorum Maxim) were set up in the outdoor. 8 antibiotics including erythromycin-H2O (ETM-H2O), monensin (MON), clarithromycin (CTM), leucomycin (LCM), sulfamethoxazole (SMX), trimethoprim (TMP), sulfamethazine (SMZ) and sulfapyridine (SPD) and 12 genes including three sulfonamide resistance genes (sul1, sul2 and sul3), four tetracycline resistance genes (tetG, tetM, tetO and tetX), two macrolide resistance genes (ermB and ermC), two chloramphenicol resistance genes (cmlA and floR) and 16S rRNA (bacteria) were determined in different matrices (water, particle, substrate and plant phases) from the mesocosm-scale systems. The aqueous removal efficiencies of total antibiotics ranged from 75.8 to 98.6%, while those of total ARGs varied between 63.9 and 84.0% by the mesocosm-scale CWs. The presence of plants was beneficial to the removal of pollutants, and the subsurface flow CWs had higher pollutant removal than the surface flow CWs, especially for antibiotics. According to the mass balance analysis, the masses of all detected antibiotics during the operation period were 247,000, 4920-10,600, 0.05-0.41 and 3500-60,000μg in influent, substrate, plant and effluent of the mesocosm-scale CWs. In the CWs, biodegradation, substrate adsorption and plant uptake all played certain roles in reducing the loadings of nutrients, antibiotics and ARGs, but biodegradation was the most important process in the removal of these pollutants. Copyright © 2016 Elsevier B.V. All rights reserved.

Prospects of passive radio detection of a subsurface ocean on Europa with a lander

NASA Astrophysics Data System (ADS)

Romero-Wolf, Andrew; Schroeder, Dustin M.; Ries, Paul; Bills, Bruce G.; Naudet, Charles; Scott, Bryan R.; Treuhaft, Robert; Vance, Steve

2016-09-01

We estimate the sensitivity of a lander-based instrument for the passive radio detection of a subsurface ocean beneath the ice shell of Europa, expected to be between 3 km and 30 km thick, using Jupiter's decametric radiation. A passive technique was previously studied for an orbiter. Using passive detection in a lander platform provides a point measurement with significant improvements due to largely reduced losses from surface roughness effects, longer integration times, and diminished dispersion due to ionospheric effects allowing operation at lower frequencies and a wider band. A passive sounder on-board a lander provides a low resource instrument sensitive to subsurface ocean at Europa up to depths of 6.9 km for high loss ice (16 dB/km two-way attenuation rate) and 69 km for pure ice (1.6 dB/km).

Data acquisition and processing system and method for investigating sub-surface features of a rock formation

DOEpatents

Vu, Cung Khac; Nihei, Kurt; Johnson, Paul A; Guyer, Robert; Ten Cate, James A; Le Bas, Pierre-Yves; Larmat, Carene S

2015-01-27

A system and a method includes generating a first signal at a first frequency; and a second signal at a second frequency. Respective sources are positioned within the borehole and controllable such that the signals intersect in an intersection volume outside the borehole. A receiver detects a difference signal returning to the borehole generated by a non-linear mixing process within the intersection volume, and records the detected signal and stores the detected signal in a storage device and records measurement parameters including a position of the first acoustic source, a position of the second acoustic source, a position of the receiver, elevation angle and azimuth angle of the first acoustic signal and elevation angle and azimuth angle of the second acoustic signal.

Beyond Darcy's law: The role of phase topology and ganglion dynamics for two-fluid flow

DOE PAGES

Armstrong, Ryan T.; McClure, James E.; Berrill, Mark A.; ...

2016-10-27

Relative permeability quantifies the ease at which immiscible phases flow through porous rock and is one of the most well known constitutive relationships for petroleum engineers. It however exhibits troubling dependencies on experimental conditions and is not a unique function of phase saturation as commonly accepted in industry practices. The problem lies in the multi-scale nature of the problem where underlying disequilibrium processes create anomalous macroscopic behavior. Here we show that relative permeability rate dependencies are explained by ganglion dynamic flow. We utilize fast X-ray micro-tomography and pore-scale simulations to identify unique flow regimes during the fractional flow of immisciblemore » phases and quantify the contribution of ganglion flux to the overall flux of non-wetting phase. We anticipate our approach to be the starting point for the development of sophisticated multi-scale flow models that directly link pore-scale parameters to macro-scale behavior. Such models will have a major impact on how we recover hydrocarbons from the subsurface, store sequestered CO 2 in geological formations, and remove non-aqueous environmental hazards from the vadose zone.« less

Development of a Design Tool for Planning Aqueous Amendment Injection Systems

DTIC Science & Technology

2008-06-01

BIOREMresources.asp) • “Protocol for Enhanced In Situ Bioremediation Using Emulsified Edible Oil” – (search for title at http://docs.serdp-estcp.org...index.cfm) • “Protocol for In Situ Bioremediation of Chlorinated Solvents Using Edible Oil” (http://www.afcee.brooks.af.mil/products/techtrans...and acetate by common subsurface microorganisms . The H2 and acetate are then used as a carbon and energy source for anaerobic biodegradation of the

Electromagnetic induction of foam-based nanoscale zerovalent iron (NZVI) particles to thermally enhance non-aqueous phase liquid (NAPL) volatilization in unsaturated porous media: Proof of concept.

PubMed

Srirattana, Supawan; Piaowan, Kitsanateen; Lowry, Gregory V; Phenrat, Tanapon

2017-09-01

Nanoscale zerovalent iron (NZVI) is a promising remediation agent for volatile organic compound (VOC) contamination in saturated sub-surfaces, but is rarely applied to the vadose zone as there are not enough water molecules in the unsaturated zone to participate in reductive dechlorination. In this study, we evaluated the possibility of using foam as a carrying vehicle to emplace NZVI in unsaturated porous media followed by the application of low frequency-electromagnetic field (LF-EMF) to enhance VOC volatilization in laboratory batch reactors. We found that the optimal condition for generating foam-based NZVI (F-NZVI) was using sodium lauryl ether sulfate (SLES) at a concentration of 3% (w/w) and a N 2 flow rate of 500 mL/min. Also, F-NZVI could carry as much as 41.31 g/L of NZVI in the liquid phase of the foam and generate heat to raise ΔT to 77 °C in 15 min under an applied LF-EMF (150 kHz and 13 A). Under these conditions, F-NZVI together with LF-EMF enhanced trichloroethylene (TCE) volatilization from TCE-dense non-aqueous phase liquid (DNAPL) in unsaturated sand by 39.51 ± 6.59-fold compared to reactors without LF-EMF application. This suggested that using F-NZVI together with LF-EMF could theoretically be an alternative to radio frequency heating (RFH) as it requires a much lower irradiation frequency (336-fold lower), which should result in significantly lower capital and operational costs compared to RFH. Copyright © 2017 Elsevier Ltd. All rights reserved.

Subsurface solute transport with one-, two-, and three-dimensional arbitrary shape sources

NASA Astrophysics Data System (ADS)

Chen, Kewei; Zhan, Hongbin; Zhou, Renjie

2016-07-01

Solutions with one-, two-, and three-dimensional arbitrary shape source geometries will be very helpful tools for investigating a variety of contaminant transport problems in the geological media. This study proposed a general method to develop new solutions for solute transport in a saturated, homogeneous aquifer (confined or unconfined) with a constant, unilateral groundwater flow velocity. Several typical source geometries, such as arbitrary line sources, vertical and horizontal patch sources, circular and volumetric sources, were considered. The sources can sit on the upper or lower aquifer boundary to simulate light non-aqueous-phase-liquids (LNAPLs) or dense non-aqueous-phase-liquids (DNAPLs), respectively, or can be located anywhere inside the aquifer. The developed new solutions were tested against previous benchmark solutions under special circumstances and were shown to be robust and accurate. Such solutions can also be used as a starting point for the inverse problem of source zone and source geometry identification in the future. The following findings can be obtained from analyzing the solutions. The source geometry, including shape and orientation, generally played an important role for the concentration profile through the entire transport process. When comparing the inclined line sources with the horizontal line sources, the concentration contours expanded considerably along the vertical direction, and shrank considerably along the groundwater flow direction. A planar source sitting on the upper aquifer boundary (such as a LNAPL pool) would lead to significantly different concentration profiles compared to a planar source positioned in a vertical plane perpendicular to the flow direction. For a volumetric source, its dimension along the groundwater flow direction became less important compared to its other two dimensions.

In Situ Biotreatment of TBA with Recirculation/Oxygenation

PubMed Central

North, Katharine P.; Mackay, Douglas M.; Kayne, Julian S.; Petersen, Daniel; Rasa, Ehsan; Rastegarzadeh, Laleh; Holland, Reef B.; Scow, Kate M.

2012-01-01

The potential for in situ biodegradation of tert-butyl alcohol (TBA) by creation of aerobic conditions in the subsurface with recirculating well pairs was investigated in two field studies conducted at Vandenberg Air Force Base (VAFB). In the first experiment, a single recirculating well pair with bromide tracer and oxygen amendment successfully delivered oxygen to the subsurface for 42 days. TBA concentrations were reduced from approximately 500 μg/L to below the detection limit within the treatment zone and the treated water was detected in a monitoring transect several meters downgradient. In the second experiment, a site-calibrated model was used to design a double recirculating well pair with oxygen amendment, which successfully delivered oxygen to the subsurface for 291 days and also decreased TBA concentrations to below the detection limit. Methylibium petroleiphilum strain PM1, a known TBA-degrading bacterium, was detectable at the study site but addition of oxygen had little impact on the already low baseline population densities, suggesting that there was not enough carbon within the groundwater plume to support significant new growth in the PM1 population. Given favorable hydrogeologic and geochemical conditions, the use of recirculating well pairs to introduce dissolved oxygen into the subsurface is a viable method to stimulate in situ biodegradation of TBA or other aerobically-degradable aquifer contaminants. PMID:23358537

In Situ Biotreatment of TBA with Recirculation/Oxygenation.

PubMed

North, Katharine P; Mackay, Douglas M; Kayne, Julian S; Petersen, Daniel; Rasa, Ehsan; Rastegarzadeh, Laleh; Holland, Reef B; Scow, Kate M

2012-01-01

The potential for in situ biodegradation of tert-butyl alcohol (TBA) by creation of aerobic conditions in the subsurface with recirculating well pairs was investigated in two field studies conducted at Vandenberg Air Force Base (VAFB). In the first experiment, a single recirculating well pair with bromide tracer and oxygen amendment successfully delivered oxygen to the subsurface for 42 days. TBA concentrations were reduced from approximately 500 μg/L to below the detection limit within the treatment zone and the treated water was detected in a monitoring transect several meters downgradient. In the second experiment, a site-calibrated model was used to design a double recirculating well pair with oxygen amendment, which successfully delivered oxygen to the subsurface for 291 days and also decreased TBA concentrations to below the detection limit. Methylibium petroleiphilum strain PM1, a known TBA-degrading bacterium, was detectable at the study site but addition of oxygen had little impact on the already low baseline population densities, suggesting that there was not enough carbon within the groundwater plume to support significant new growth in the PM1 population. Given favorable hydrogeologic and geochemical conditions, the use of recirculating well pairs to introduce dissolved oxygen into the subsurface is a viable method to stimulate in situ biodegradation of TBA or other aerobically-degradable aquifer contaminants.

Distinct Iron-binding Ligands in the Upper Water Column at Station ALOHA

NASA Astrophysics Data System (ADS)

Bundy, R.; Boiteau, R.; Repeta, D.

2016-02-01

The distribution and chemical properties of iron-binding organic ligands at station ALOHA were examined using a combination of solid phase extraction (SPE) followed by high pressure liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS). HPLC-ICPMS ligand measurements were complemented by competitive ligand exchange adsorptive cathodic stripping voltammetry (CLE-ACSV) analysis using salicylaldoxime as the added ligand. By HPLC-ICPMS, we find enhanced concentrations of distinct naturally-occurring polar iron-binding ligands present at the surface and in the chlorophyll maximum. Lower concentrations were found in the subsurface, where a suite of non-polar ligands was detected. Siderophores were present at the deepest depths sampled at station ALOHA, down to 400m. Incubation studies provided evidence for the production of iron-binding ligands associated with nutrient amended phytoplankton growth in surface waters, and as a result of microbial particle remineralization in the subsurface water column. Ligands classes identified via SPE were then compared to CLE-ACSV ligand measurements, as well as the conditional stability constants measured from model polar and non-polar siderophores, yielding insight to the sources of iron-binding ligands throughout the water column at station ALOHA.

Hypoglycemic effect of Carica papaya leaves in streptozotocin-induced diabetic rats.

PubMed

Juárez-Rojop, Isela Esther; Díaz-Zagoya, Juan C; Ble-Castillo, Jorge L; Miranda-Osorio, Pedro H; Castell-Rodríguez, Andrés E; Tovilla-Zárate, Carlos A; Rodríguez-Hernández, Arturo; Aguilar-Mariscal, Hidemi; Ramón-Frías, Teresa; Bermúdez-Ocaña, Deysi Y

2012-11-28

Traditional plant treatment for diabetes has shown a surging interest in the last few decades. Therefore, the purpose of this study was to assess the hypoglycemic effect of the aqueous extract of C. papaya leaves in diabetic rats. Several studies have reported that some parts of the C. papaya plant exert hypoglycemic effects in both animals and humans. Diabetes was induced in rats by intraperitoneal administration of 60 mg/kg of streptozotocin (STZ). The aqueous extract of C. papaya was administered in three different doses (0.75, 1.5 and 3 g/100 mL) as drinking water to both diabetic and non-diabetic animals during 4 weeks. The aqueous extract of Carica papaya (0.75 g and 1.5 g/100 mL) significantly decreased blood glucose levels (p<0.05) in diabetic rats. It also decreased cholesterol, triacylglycerol and amino-transferases blood levels. Low plasma insulin levels did not change after treatment in diabetic rats, but they significantly increased in non-diabetic animals. Pancreatic islet cells were normal in non-diabetic treated animals, whereas in diabetic treated rats, C. papaya could help islet regeneration manifested as preservation of cell size. In the liver of diabetic treated rats, C. papaya prevented hepatocyte disruption, as well as accumulation of glycogen and lipids. Finally, an antioxidant effect of C. papaya extract was also detected in diabetic rats. This study showed that the aqueous extract of C. papaya exerted a hypoglycemic and antioxidant effect; it also improved the lipid profile in diabetic rats. In addition, the leaf extract positively affected integrity and function of both liver and pancreas.

The Influence of Hydrophilic Interactions on the Sorption and Mobility of Naproxen at Environmentally-Relevant Concentrations

NASA Astrophysics Data System (ADS)

Muller, K.; Ramsburg, C. A.

2011-12-01

Managed underground storage of reclaimed wastewater is currently one viable option for meeting increasing demands on water resources, yet the attenuation of many emerging contaminants within the subsurface environment is not well understood. Pharmaceuticals are of particular concern due to the rapid increase in development and use of these compounds, observations of incomplete removal during wastewater treatment, and emerging concerns over ecosystem effects. Assessment of the subsurface attenuation of pharmaceuticals is difficult because the compounds are polar, pH-active, and present at low-concentration (ng/L). Predictions of sorption that only consider hydrophobic interactions with soil organic matter may not fully describe the extent to which reversible sequestration influences pharmaceutical attenuation. In fact, hydrophilic interactions (i.e. ion exchange, cation-induced sorption, hydrogen bonding, etc) may represent important contributions to total sorption, especially when aqueous solutes are present at low concentration. Here we assess the sorption of naproxen - an acidic pharmaceutical - to three subsurface materials using equilibrium batch experiments and 1-d column experiments. Subsurface materials evaluated include Ottawa sand (quartz with negligible organic carbon and negligible iron oxide), Aplite sand (quartz and feldspar with negligible organic carbon, 0.2% wt iron oxide), and a Hinckley series silty-sand (quartz and feldspar with 0.95% wt organic carbon, and 0.4% wt iron oxides). Sorption of naproxen to the Ottawa sand was negligible and did not result in measurable retardation when naproxen was introduced to the porous medium at a concentration of 275 ng/L. Batch experiments suggest that Aplite sand offers quantifiable interaction (52% of the mass introduced is associated with the solid phase when the aqueous concentration is 1000 ng/L and the solid to liquid ratio is 1.4:1 v/v); however, column data are indicative of markedly less interaction and retardation. Naproxen sorption to the Hinckley series material was considerable (99% of the mass introduced is associated with the solid phase when the aqueous concentration is 1000 ng/L and the solid to liquid ratio is 1:1 v/v). Predictions of naproxen sorption based upon the fraction of organic carbon and the organic-carbon partitioning coefficient (Koc) greatly underestimated the sorption observed in all experiments conducted with the Hinckley series material. Assessment of sorption under 1 mM NaH2PO4 (a sorbant with a strong affinity for hydrophilic sites) suggests that hydrophobic interactions account for approximately 45% of the total interaction. Breakthrough of naproxen (C0 ~ 20 ug/L) was substantially retarded in experiments conducted with the Hinckley material and a thermally-treated Hinckley material (negligible organic carbon). These results highlight the potential role of hydrophilic interactions during the transport and attenuation of acidic pharmaceuticals at solute concentrations typical of water reuse applications.

Applying model abstraction techniques to optimize monitoring networks for detecting subsurface contaminant transport

USDA-ARS?s Scientific Manuscript database

Improving strategies for monitoring subsurface contaminant transport includes performance comparison of competing models, developed independently or obtained via model abstraction. Model comparison and parameter discrimination involve specific performance indicators selected to better understand s...

BIODEGRADATION OF ATRAZINE IN SUBSURFACE ENVIRONMENTS

EPA Science Inventory

The pesticide atrazine is frequently detected in ground water, including ground water used as drinking water. Little information is available on the fate of atrazine in the subsurface, including its biodegradability. The objectives of this study were to evaluate the biodegradabil...

Fiber Optic Bragg Grating Sensors for Thermographic Detection of Subsurface Anomalies

NASA Technical Reports Server (NTRS)

Allison, Sidney G.; Winfree, William P.; Wu, Meng-Chou

2009-01-01

Conventional thermography with an infrared imager has been shown to be an extremely viable technique for nondestructively detecting subsurface anomalies such as thickness variations due to corrosion. A recently developed technique using fiber optic sensors to measure temperature holds potential for performing similar inspections without requiring an infrared imager. The structure is heated using a heat source such as a quartz lamp with fiber Bragg grating (FBG) sensors at the surface of the structure to detect temperature. Investigated structures include a stainless steel plate with thickness variations simulated by small platelets attached to the back side using thermal grease. A relationship is shown between the FBG sensor thermal response and variations in material thickness. For comparison, finite element modeling was performed and found to agree closely with the fiber optic thermography results. This technique shows potential for applications where FBG sensors are already bonded to structures for Integrated Vehicle Health Monitoring (IVHM) strain measurements and can serve dual-use by also performing thermographic detection of subsurface anomalies.

System and method for investigating sub-surface features of a rock formation with acoustic sources generating coded signals

DOEpatents

Vu, Cung Khac; Nihei, Kurt; Johnson, Paul A; Guyer, Robert; Ten Cate, James A; Le Bas, Pierre-Yves; Larmat, Carene S

2014-12-30

A system and a method for investigating rock formations includes generating, by a first acoustic source, a first acoustic signal comprising a first plurality of pulses, each pulse including a first modulated signal at a central frequency; and generating, by a second acoustic source, a second acoustic signal comprising a second plurality of pulses. A receiver arranged within the borehole receives a detected signal including a signal being generated by a non-linear mixing process from the first-and-second acoustic signal in a non-linear mixing zone within the intersection volume. The method also includes-processing the received signal to extract the signal generated by the non-linear mixing process over noise or over signals generated by a linear interaction process, or both.

Integrated system for investigating sub-surface features of a rock formation

DOEpatents

Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt; Johnson, Paul A.; Guyer, Robert; Ten Cate, James A.; Le Bas, Pierre -Yves; Larmat, Carene S.

2015-08-18

A system for investigating non-linear properties of a rock formation around a borehole is provided. The system includes a first sub-system configured to perform data acquisition, control and recording of data; a second subsystem in communication with the first sub-system and configured to perform non-linearity and velocity preliminary imaging; a third subsystem in communication with the first subsystem and configured to emit controlled acoustic broadcasts and receive acoustic energy; a fourth subsystem in communication with the first subsystem and the third subsystem and configured to generate a source signal directed towards the rock formation; and a fifth subsystem in communication with the third subsystem and the fourth subsystem and configured to perform detection of signals representative of the non-linear properties of the rock formation.

Detection of microbes in the subsurface

NASA Technical Reports Server (NTRS)

White, David C.; Tunlid, Anders

1989-01-01

The search for evidence of microbial life in the deep subsurface of Earth has implications for the Mars Rover Sampling Return Missions program. If suitably protected environments can be found on Mars then the instrumentation to detect biomarkers could be used to examine the molecular details. Finding a lipid in Martian soil would represent possibly the simplest test for extant or extinct life. A device that could do a rapid extraction possibly using the supercritical fluid technology under development now with a detection of the carbon content would clearly indicate a sample to be returned.

Infrared Photothermal Radiometry.

DTIC Science & Technology

1984-04-10

changes whenever the transmitted thermal wave crosses a void. This provides a means of nondestructive subsurface imaging of defects, and Busse found that...15 In the flash excitation, the excitation beam is modulated by a broad spectrum of Fourier modulation frequencies. In all cases of subsurface imaging , the...technique of Nordal and Kanstad 2 1t 23 is not only good for spectroscopic detection, but also for subsurface imaging applications as well. 2.4 Pulsed

Mapping Microbial Populations Relative to Sites of Ongoing Serpentinization: Results from the Tablelands Ophiolite Complex, Canada

NASA Astrophysics Data System (ADS)

Schrenk, M. O.; Brazelton, W. J.; Woodruff, Q.; Szponar, N.; Morrill, P. L.

2010-12-01

The aqueous alteration of ultramafic rocks (serpentinization) has been suggested to be a favorable process for the habitability of astrobodies in our solar system including subsurface environments of Mars and Europa. Serpentinization produces copious quantities of hydrogen and small organic molecules, and leads to highly reducing, highly alkaline conditions (up to pH 12) and a lack of dissolved inorganic carbon, which both stimulates and challenges microbial activities. Several environments on Earth provide insight into the relationships between serpentinization and microbial life including slow-spreading mid-ocean ridges, subduction zones, and ophiolite materials emplaced along continental margins. The Tablelands, an ophiolite in western Newfoundland, Canada provides an opportunity to carefully document and map the relationships between geochemical energy, microbial growth, and physiology. Alkaline fluids at the Tablelands originate from 500-million year old oceanic crust and accumulate in shallow pools or seep from beneath serpentinized talus. Fluids, rocks, and gases were collected from the Tablelands during a series of field excursions in 2009 and 2010, and geochemical, microscopic, molecular, and cultivation-based approaches were used to study the serpentinite microbial ecosystem. These samples provide an opportunity to generate a comprehensive map of microbial communities and their activities in space and time. Data indicate that a low but detectable stock of microorganisms inhabit high pH pools associated with end-member serpentinite fluids. Enrichment cultures yielded brightly pigmented colonies related to Alphaproteobacteria, presumably carrying out anoxygenic photosynthesis, and Firmicutes, presumably catalyzing the fermentation of organic matter. Culture-independent analyses of SSU rRNA using T-RFLP indicated low diversity communities of Firmicutes and Archaea in standing alkaline pools, communities of Beta- and Gammaproteobacteria at high pH seeps, and assemblages consisting of diverse taxa at neutral pH background sites. Terrestrial serpentinite-hosted microbial ecosystems with their accessibility, their low phylogenetic diversity, and limited range of energetic resources provide an excellent opportunity to explore the interplay between geochemical energy and life and to elucidate the native serpentinite subsurface biosphere. From the perspective of Mars exploration, studies of serpentinite ecosystems provide the opportunity to pinpoint the organisms and physiological adaptations specifically associated with serpentinization and to directly measure their geochemical impacts. Both of these results will inform modeling and life detection efforts of the Martian subsurface environment.

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2012 CFR

2012-07-01

... rigorous statistical experimental design and interpretation (Reference 16.4). 14.0Pollution Prevention 14... fluids. 1.4This method has been designed to show positive contamination for 5% of representative crude....1Sample collection bottles/jars—New, pre-cleaned bottles/jars, lot-certified to be free of artifacts...

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2013 CFR

2013-07-01

... rigorous statistical experimental design and interpretation (Reference 16.4). 14.0Pollution Prevention 14... fluids. 1.4This method has been designed to show positive contamination for 5% of representative crude....1Sample collection bottles/jars—New, pre-cleaned bottles/jars, lot-certified to be free of artifacts...

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2014 CFR

2014-07-01

... rigorous statistical experimental design and interpretation (Reference 16.4). 14.0Pollution Prevention 14... fluids. 1.4This method has been designed to show positive contamination for 5% of representative crude....1Sample collection bottles/jars—New, pre-cleaned bottles/jars, lot-certified to be free of artifacts...

40 CFR Appendix 6 to Subpart A of... - Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non-Aqueous Drilling...

Code of Federal Regulations, 2011 CFR

2011-07-01

... rigorous statistical experimental design and interpretation (Reference 16.4). 14.0Pollution Prevention 14... oil contamination in drilling fluids. 1.4This method has been designed to show positive contamination....1Sample collection bottles/jars—New, pre-cleaned bottles/jars, lot-certified to be free of artifacts...

Separation and simultaneous determination of rutin, puerarin, daidzein, esculin and esculetin in medicinal preparations by non-aqueous capillary.

PubMed

Li, Cunhong; Chen, Anjia; Chen, Xiaofeng; Chen, Xingguo; Hu, Zhide

2005-09-01

A simple method for the simultaneous determination of five bioactive components (rutin, puerarin, daidzein esculin and esculetin) in traditional medicinal preparations by non-aqueous capillary electrophoresis with UV detection has been developed for the first time. A running buffer composed of 15% acetonitrile, 2.5% acetic acid and 90 mM sodium cholate in methanol was found to be the most suitable for this separation. The limits of detection for five analytes were over the range of 0.050-1.216 microg ml(-1). The relative standard deviations (R.S.Ds.) of the migration times and the peak areas of the analytes were in the range of 1.3-2.9% and 2.2-2.7% (intraday), 1.7-1.9% and 2.8-3.6% (interday), respectively. In the tested concentration range, linear relationships (correlation coefficients: 0.9974 for rutin, 0.9976 for puerarin, 0.9981 for daidzein, 0.9972 for esculin and 0.9929 for esculetin) between peak areas and concentrations of the analytes were obtained. This method has been successfully applied to simultaneous determination of the five bioactive components with recoveries over the range of 89.4-107.4%.

A fluorescent sensor for selective detection of cyanide using mesoporous graphitic carbon(IV) nitride.

PubMed

Lee, Eun Zoo; Lee, Sun Uk; Heo, Nam-Su; Stucky, Galen D; Jun, Young-Si; Hong, Won Hi

2012-04-25

A turn-on fluorescence sensor, Cu(2+)-c-mpg-C(3)N(4), was developed for detection of CN(-) in aqueous solution by simply mixing cubic mesoporous graphitic carbon nitride (c-mpg-C(3)N(4)) and aqueous solution of Cu(NO(3))(2). The highly sensitive detection of CN(-) with a detection limit of 80 nM is not only possible in aqueous solution but also in human blood serum.

Constraints on the thermal history of Taylorsville Basin, Virginia, U.S.A., from fluid-inclusion and fission-track analyses: Implications for subsurface geomicrobiology experiments

USGS Publications Warehouse

Tseng, H.-Y.; Onstott, T.C.; Burruss, R.C.; Miller, D.S.

1996-01-01

Microbial populations have been found at the depth of 2621-2804 m in a borehole near the center of Triassic Taylorsville Basin, Virginia. To constrain possible scenarios for long-term survival in or introduction of these microbial populations to the deep subsurface, we attempted to refine models of thermal and burial history of the basin by analyzing aqueous and gaseous fluid inclusions in calcite/quartz veins or cements in cuttings from the same borehole. These results are complemented by fission-track data from the adjacent boreholes. Homogenization temperatures of secondary aqueous fluid inclusions range from 120?? to 210??C between 2027- and 3069-m depth, with highest temperatures in the deepest samples. The salinities of these aqueous inclusions range from 0 to ??? 4.3 eq wt% NaCl. Four samples from the depth between 2413 and 2931 m contain both two-phase aqueous and one-phase methane-rich inclusions in healed microcracks. The relative CH4 and CO2 contents of these gaseous inclusions was estimated by microthermometry and laser Raman spectroscopy. If both types of inclusions in sample 2931 m were trapped simultaneously, the density of the methane-rich inclusions calculated from the Peng - Robinson equation of state implies an entrapment pressure of 360 ?? 20 bar at the homogenization temperature (162.5 ?? 12.5??C) of the aqueous inclusions. This pressure falls between the hydrostatic and lithostatic pressures at the present depth 2931 m of burial. If we assume that the pressure regime was hydrostatic at the time of trapping, then the inclusions were trapped at 3.6 km in a thermal gradient of ??? 40??C/km. The high temperatures recorded by the secondary aqueous inclusions are consistent with the pervasive resetting of zircon and apatite fission-track dates. In order to fit the fission-track length distributions of the apatite data, however, a cooling rate of 1-2??C/Ma following the thermal maximum is required. To match the integrated dates, the thermal maximum would have occurred at ??? 200 Ma. The timing of the maximum temperature is consistent with rapid burial of the Taylorsville Basin to twice its present-day depth and thermal re-equilibration with a 40??C/km geothermal gradient, followed by slow exhumation. The results may imply that the microorganisms did not survive in situ, but were transported from the cooler portions of the basin sometime after maximum burial and heating.

Iron-based subsurface arsenic removal technologies by aeration: A review of the current state and future prospects.

PubMed

Luong, Vu T; Cañas Kurz, Edgardo E; Hellriegel, Ulrich; Luu, Tran L; Hoinkis, Jan; Bundschuh, Jochen

2018-04-15

Arsenic contamination in groundwater is a critical issue and one that raises great concern around the world as the cause of many negative health impacts on the human body, including internal and external cancers. There are many ways to remove or immobilize arsenic, including membrane technologies, adsorption, sand filtration, ion exchange, and capacitive deionization. These exhibit many different advantages and disadvantages. Among these methods, in-situ subsurface arsenic immobilization by aeration and the subsequent removal of arsenic from the aqueous phase has shown to be very a promising, convenient technology with high treatment efficiency. In contrast to most of other As remediation technologies, in-situ subsurface immobilization offers the advantage of negligible waste production and hence has the potential of being a sustainable treatment option. This paper reviews the application of subsurface arsenic removal (SAR) technologies as well as current modeling approaches. Unlike subsurface iron removal (SIR), which has proven to be technically feasible in a variety of hydrogeochemical settings for many years, SAR is not yet an established solution since it shows vulnerability to diverse geochemical conditions such as pH, Fe:As ratio, and the presence of co-ions. In some situations, this makes it difficult to comply with the stringent guideline value for drinking water recommended by the WHO (10 μg L -1 ). In order to overcome its limitations, more theoretical and experimental studies are needed to show long-term application achievements and help the development of SAR processes into state-of-the-art technology. Copyright © 2018 Elsevier Ltd. All rights reserved.

ZnS/Zn(O,OH)S-based buffer layer deposition for solar cells

DOEpatents

Bhattacharya, Raghu N [Littleton, CO

2009-11-03

The invention provides CBD ZnS/Zn(O,OH)S and spray deposited ZnS/Zn(O,OH)S buffer layers prepared from a solution of zinc salt, thiourea and ammonium hydroxide dissolved in a non-aqueous/aqueous solvent mixture or in 100% non-aqueous solvent. Non-aqueous solvents useful in the invention include methanol, isopropanol and triethyl-amine. One-step deposition procedures are described for CIS, CIGS and other solar cell devices.

Low-Level Detection of a Bacillus Anthracis Simulant using Love-Wave Biosensors on 36 Degree YX LiTaO3

DOE Office of Scientific and Technical Information (OSTI.GOV)

BRANCH,DARREN W.; BROZIK,SUSAN M.

Crucial to low-level detection of biowarfare agents in aqueous environments is the mass sensitivity optimization of Love-wave acoustic sensors. The present work is an experimental study of 36{sup o} YX cut LiTaO{sub 3} based Love-wave devices for detection of pathogenic spores in aqueous conditions. Given that the detection limit (DL) of Love-wave based sensors is a strong function of the overlying waveguide, two waveguide materials have been investigated, which are polyimide and polystyrene. To determine the mass sensitivity of Love-wave sensor, bovine serum albumin (BSA) protein was injected into the Love-wave test cell while recording magnitude and phase shift acrossmore » each sensor. Polyimide had the lowest mass detection limit with an estimated value of 1-2 ng/cm{sup 2}, as compared to polystyrene where DL = 2.0 ng/cm{sup 2}. Suitable chemistries were used to orient antibodies on the Love-wave sensor using adsorbed protein G. The thickness of each biofilm was measured using ellipsometry from which the surface concentrations were calculated. The monoclonal antibody BD8 with a high degree of selectivity for anthrax spores was used to capture the non-pathogenic simulant B. thuringiensis B8 spores. Bacillus Subtilis spores were used as a negative control to determine whether significant non-specific binding would occur. Spore aliquots were prepared using an optical counting method, which permitted removal of background particles for consistent sample preparation. This work demonstrates that Love-wave devices can be used to detect B. anthracis simulant below reported infectious levels.« less

Fe(III) reduction and U(VI) immobilization by Paenibacillus sp. strain 300A, isolated from Hanford 300A subsurface sediments.

PubMed

Ahmed, Bulbul; Cao, Bin; McLean, Jeffrey S; Ica, Tuba; Dohnalkova, Alice; Istanbullu, Ozlem; Paksoy, Akin; Fredrickson, Jim K; Beyenal, Haluk

2012-11-01

A facultative iron-reducing [Fe(III)-reducing] Paenibacillus sp. strain was isolated from Hanford 300A subsurface sediment biofilms that was capable of reducing soluble Fe(III) complexes [Fe(III)-nitrilotriacetic acid and Fe(III)-citrate] but unable to reduce poorly crystalline ferrihydrite (Fh). However, Paenibacillus sp. 300A was capable of reducing Fh in the presence of low concentrations (2 μM) of either of the electron transfer mediators (ETMs) flavin mononucleotide (FMN) or anthraquinone-2,6-disulfonate (AQDS). Maximum initial Fh reduction rates were observed at catalytic concentrations (<10 μM) of either FMN or AQDS. Higher FMN concentrations inhibited Fh reduction, while increased AQDS concentrations did not. We also found that Paenibacillus sp. 300A could reduce Fh in the presence of natural ETMs from Hanford 300A subsurface sediments. In the absence of ETMs, Paenibacillus sp. 300A was capable of immobilizing U(VI) through both reduction and adsorption. The relative contributions of adsorption and microbial reduction to U(VI) removal from the aqueous phase were ∼7:3 in PIPES [piperazine-N,N'-bis(2-ethanesulfonic acid)] and ∼1:4 in bicarbonate buffer. Our study demonstrated that Paenibacillus sp. 300A catalyzes Fe(III) reduction and U(VI) immobilization and that these reactions benefit from externally added or naturally existing ETMs in 300A subsurface sediments.

Fe(III) Reduction and U(VI) Immobilization by Paenibacillus sp. Strain 300A, Isolated from Hanford 300A Subsurface Sediments

PubMed Central

Ahmed, Bulbul; Cao, Bin; McLean, Jeffrey S.; Ica, Tuba; Dohnalkova, Alice; Istanbullu, Ozlem; Paksoy, Akin; Fredrickson, Jim K.

2012-01-01

A facultative iron-reducing [Fe(III)-reducing] Paenibacillus sp. strain was isolated from Hanford 300A subsurface sediment biofilms that was capable of reducing soluble Fe(III) complexes [Fe(III)-nitrilotriacetic acid and Fe(III)-citrate] but unable to reduce poorly crystalline ferrihydrite (Fh). However, Paenibacillus sp. 300A was capable of reducing Fh in the presence of low concentrations (2 μM) of either of the electron transfer mediators (ETMs) flavin mononucleotide (FMN) or anthraquinone-2,6-disulfonate (AQDS). Maximum initial Fh reduction rates were observed at catalytic concentrations (<10 μM) of either FMN or AQDS. Higher FMN concentrations inhibited Fh reduction, while increased AQDS concentrations did not. We also found that Paenibacillus sp. 300A could reduce Fh in the presence of natural ETMs from Hanford 300A subsurface sediments. In the absence of ETMs, Paenibacillus sp. 300A was capable of immobilizing U(VI) through both reduction and adsorption. The relative contributions of adsorption and microbial reduction to U(VI) removal from the aqueous phase were ∼7:3 in PIPES [piperazine-N,N′-bis(2-ethanesulfonic acid)] and ∼1:4 in bicarbonate buffer. Our study demonstrated that Paenibacillus sp. 300A catalyzes Fe(III) reduction and U(VI) immobilization and that these reactions benefit from externally added or naturally existing ETMs in 300A subsurface sediments. PMID:22961903

Fe(III) Reduction and U(VI) Immobilization by Paenibacillus sp. Strain 300A, Isolated from Hanford 300A Subsurface Sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmed, B.; Cao, B.; McLean, Jeffrey S.

2012-11-07

A facultative iron-reducing (Fe(III)-reducing) Paenibacillus sp. strain was isolated from Hanford 300A subsurface sediment biofilms that was capable of reducing soluble Fe(III) complexes (Fe(III)-NTA and Fe(III)-citrate) but unable to reduce poorly crystalline ferrihydrite (Fh). However, Paenibacillus sp. 300A was capable of reducing Fh in the presence of low concentrations (2 µM) of either of electron transfer mediators (ETMs) flavin mononucleotide (FMN) or anthraquinone-2,6-disulfonate (AQDS). Maximum initial Fh reduction rates were observed at catalytic concentrations (<10 µM) of either FMN or AQDS. Higher FMN concentrations inhibited Fh reduction, while increased AQDS concentrations did not. We found that Paenibacillus sp. 300A alsomore » could reduce Fh in the presence of natural ETMs from Hanford 300A subsurface sediments. In the absence of ETMs, Paenibacillus sp. 300A was capable of immobilizing U(VI) through both reduction and adsorption. The relative contributions of adsorption and microbial reduction to U(VI) removal from the aqueous phase were ~7:3 in PIPES and ~1:4 in bicarbonate buffer. Our study demonstrated that Paenibacillus sp. 300A catalyzes Fe(III) reduction and U(VI) immobilization and that these reactions benefit from externally added or naturally existing ETMs in 300A subsurface sediments.« less

Thermometric titration of some monoprotic and diprotic acids in aqueous and non-aqueous media.

PubMed

Harries, R J

1968-12-01

Some mono- and diprotic acids have been titrated thermometrically with strong alkalis in aqueous and non-aqueous media. Thermograms with sharp arrest points were obtained, from which heats of neutralization were measured. Heats of neutralization in the media used were compared and an effect attributable to hydrogen bonding was found.

HPLC-DAD-MS identification of bioactive secondary metabolites from Ferula communis roots.

PubMed

Arnoldi, Lolita; Ballero, Mauro; Fuzzati, Nicola; Maxia, Andrea; Mercalli, Enrico; Pagni, Luca

2004-06-01

A simple HPLC method was developed to distinguish between 'poisonous' and 'non-poisonous' chemotypes of Ferula communis. The method was performed on a C8 reverse phase analytical column using a binary eluent (aqueous TFA 0.01%-TFA 0.01% in acetonitrile) under gradient condition. The two chemotypes showed different fingerprints. The identification of five coumarins and eleven daucane derivatives by HPLC-diode array detection (HPLC-DAD) and HPLC-MS is described. A coumarin, not yet described, was detected. Copyright 2004 Elsevier B.V.

Ground-atmosphere interactions at Gale

NASA Astrophysics Data System (ADS)

Renno, N. O.; Martinez, G.; Ramos, M.; Hallet, B.; Gómez, F. G.; Jun, I.; Fisk, M. R.; Gomez-Elvira, J.; Hamilton, V. E.; Mischna, M. A.; Sletten, R. S.; Martin-Torres, J.; De La Torre Juarez, M.; Vasavada, A. R.; Zorzano, M.

2013-12-01

We analyze variations in environmental parameters and regolith properties along Curiosity's track to determine the possible causes of an abrupt change in the thermal properties of the ground and the atmosphere observed around Sol 120, as the rover transitioned from an area of sandy soil (Rocknest) to an area of fractured bedrock terrain (Yellowknife). Curiosity is instrumented with the Rover Environmental Monitoring Station (REMS) and the Dynamic Albedo of Neutrons (DAN) sensors to measure the air temperature, the ground temperature, and the hydrogen content of the shallow subsurface along Curiosity's track. Analysis of the REMS data is used to estimate the regolith's heat budget. This analysis suggests that the abrupt decrease in the ground and atmosphere temperature and the difference between ground and air temperatures observed around Sol 120 is likely caused by an increase in the soil thermal inertia. The changes in thermal inertia have been known for some time so confirming this by the REMS package provides ground truthing. A new unexpected finding is that the regolith water content, as indicated by DAN's detection of hydrogen content, is higher in the Yellowknife soil. Another interesting finding at this site are the holes and other signs of recent geological activity in the area of fractured terrain that may reflect large volumetric variations and facilitate gas exchange between the ground and atmosphere. Near-surface volumetric changes in soil and bedrock could reflect changes in the volume of subsurface H2O, or in the partitioning of H2O among its three phases. Volume increases could also result from salt crystal growth in rock pores and soil pores associated with the adsorption of water vapor. Crystallization in pores is a significant weathering process on Earth; it could well be active on Mars. Salts also inhibits the exchange of moisture between the ground and the atmosphere, and cements the soils of arid places such as in the McMurdo Dry Valleys in Antarctica. Indeed, salts might be responsible for the ubiquitous martian duricrust. More importantly, salt crusts have the potential to create pockets of wet regolith in the shallow martian subsurface that could be habitable. A better understanding of ground-atmosphere interactions has the potential to shed new light into aqueous processes in the shallow martian subsurface.

Laser Trabeculoplasty Induces Changes in the Trabecular Meshwork Glycoproteome: A pilot study

PubMed Central

Amelinckx, Adriana; Castello, Maria; Arrieta-Quintero, Esdras; Lee, Tinthu; Salas, Nelson; Hernandez, Eleut; Lee, Richard K.; Bhattacharya, Sanjoy K.; Parel, Jean-Marie A

2009-01-01

Laser trabeculoplasty (LT) is a commonly used modality of treatment for glaucoma. The mechanism by which LT lowers the intraocular pressure (IOP) is unknown. Using cat eyes, selective laser trabeculoplasty (SLT) with a Q-switched frequency doubled Nd:YAG laser was used to treat the trabecular meshwork (TM). Laser treated TM was then subjected to proteomic analysis for detection of molecular changes and histological analysis for the detection of structural and protein expression patterns. In addition, the protein glycosylation patterns of laser treated and non-treated TM was assessed and differentially glycosylated proteins were proteomically identified. SLT laser treatment to the TM resulted in elevated glycosylation levels compared to non-lasered TM. TM laser treatment also resulted in protein expression levels changes of several proteins. Elevated levels of biglycan, keratocan and prolargin were detected in laser treated TM compared to non-lasered controls. Further investigation is anticipated to provide insight into how glycosylation changes affect TM proteins and TM regulation of aqueous outflow in response to laser trabeculoplasty. PMID:19432485

Investigation of lunar maria structure from cross-analysis of GRAIL gravity and Kaguya radar data

NASA Astrophysics Data System (ADS)

Zuber, M. T.; Ermakov, A.; Smith, D. E.; Mastroguiseppe, M.; Raguso, M.

2016-12-01

The Lunar Radar Sounder (LRS) on JAXA's Kaguya spacecraft investigated the subsurface structure of the Moon to a depth of a few km. GRAIL gravity models are potentially sensitive to subsurface structure at such depths. GRAIL gravity and LRS radar data are complementary since both are sensitive to density/compositional heterogeneities. Cross-correlation of GRAIL and LRS data has the potential to produce new constraints on the structure and evolution of the lunar maria. Originally, subsurface reflections within the lunar maria were detected with Lunar Sounder Experiment aboard Apollo 17. Subsurface layering was attributed to multiple episodes of volcanism. Later, Kaguya's LRS produced similar measurements but with global-scale coverage. Laboratory measurements show that density variations among mare basalts can be up to 200 kg m-3 or 7%. The LRS measurements have detected subsurface reflection in the upper 1 km of the crust. Combining these two estimates and using the Bouguer slab approximation, we estimate that anomalies of order 1-10 mGal are expected due to potentially varying density of surface and/or subsurface horizons. This accuracy is achievable with the latest GRAIL gravity models. The LRS surface backscattering power is indicative of surface and near sub-surface dielectric properties, which are sensitive to target density and roughness. We investigate the northwestern part of the Procellarum basin because it is the region with the strongest signal-to-noise ratios in gravity models within maria. To examine shallow subsurface structure, we map the surface received power by tracking the first return of radar echoes and compare it with gravity gradients, which are particularly sensitive to small-scale structures.

Detection of Subsurface Material Separation in Shuttle Orbiter Slip-Side Joggle Region of the Wing Leading Edge using Infrared Imaging Data from Arc Jet Tests

NASA Technical Reports Server (NTRS)

Daryabeigi, Kamran; Walker, Sandra P.

2009-01-01

The objective of the present study was to determine whether infrared imaging (IR) surface temperature data obtained during arc-jet tests of Space Shuttle Orbiter s reinforced carbon-carbon (RCC) wing leading edge panel slip-side joggle region could be used to detect presence of subsurface material separation, and if so, to determine when separation occurs during the simulated entry profile. Recent thermostructural studies have indicated thermally induced interlaminar normal stress concentrations at the substrate/coating interface in the curved joggle region can result in local subsurface material separation, with the separation predicted to occur during approach to peak heating during reentry. The present study was an attempt to determine experimentally when subsurface material separations occur. A simplified thermal model of a flat RCC panel with subsurface material separation was developed and used to infer general surface temperature trends due to the presence of subsurface material separation. IR data from previously conducted arc-jet tests on three test specimens were analyzed: one without subsurface material separation either pre or post test, one with pre test separation, and one with separation developing during test. The simplified thermal model trend predictions along with comparison of experimental IR data of the three test specimens were used to successfully infer material separation from the arc-jet test data. Furthermore, for the test specimen that had developed subsurface material separation during the arc-jet tests, the initiation of separation appeared to occur during the ramp up to the peak heating condition, where test specimen temperature went from 2500 to 2800 F.

Non-ferromagnetic overburden casing

DOEpatents

Vinegar, Harold J.; Harris, Christopher Kelvin; Mason, Stanley Leroy

2010-09-14

Systems, methods, and heaters for treating a subsurface formation are described herein. At least one system for electrically insulating an overburden portion of a heater wellbore is described. The system may include a heater wellbore located in a subsurface formation and an electrically insulating casing located in the overburden portion of the heater wellbore. The casing may include at least one non-ferromagnetic material such that ferromagnetic effects are inhibited in the casing.

Mind the Gaps: Expert and Non-Expert Differences in Conceptualising the Geological Subsurface.

NASA Astrophysics Data System (ADS)

Gibson, H.; Stewart, I. S.; Stokes, A.; Pahl, S.

2017-12-01

In communicating geoscience topics, emphasis is often given to approaches such as the use of narrative to make a message engaging and reducing the use of jargon to ensure that it is understood by as wide a group of people as possible. Whilst these are undeniably important techniques to promote effective communication, an aspect of geoscience communication that is often overlooked is the publics' conceptual frameworks about core geoscience concepts. The consideration of different conceptual frameworks fits with the need to ensure that the framing is appropriate for the message, but it extends beyond simple framing into more complicated issues of addressing and incorporating pre- and mis-conceptions in geoscience. In a study examining expert and non-expert cognitive (mental) models of the geological subsurface in south-west England, several gaps were found between the fundamental ways that experts and non-experts conceptualise this invisible realm. Of these, three gaps were considered to be particularly important and common to many participants: the use of spatial reasoning; the application of surface experiences to subsurface processes; and the connection between the surface and subsurface. This paper will examine the evidence for these three important conceptual gaps between specialists and non-specialists and will address how this type of cognitive study can help improve effective geoscience communication.

Exploring the fatty acids of vernix caseosa in form of their methyl esters by off-line coupling of non-aqueous reversed phase high performance liquid chromatography and gas chromatography coupled to mass spectrometry.

PubMed

Hauff, Simone; Vetter, Walter

2010-12-24

Vernix caseosa is a greasy biofilm formed on the skin of the human fetus in the last period of pregnancy. This matrix is known to contain a range of uncommon branched chain fatty acids. In this study, we studied the fatty acid composition of vernix caseosa by non-aqueous reversed phase high performance liquid chromatography (RP-HPLC) fractionation followed by gas chromatography-electron ionization mass spectrometry (GC/EI-MS) of the fractions. For this purpose the fatty acids from vernix caseosa were converted into the corresponding methyl esters. These were fractionated by non-aqueous RP-HPLC using three serially connected C(18)-columns and pure methanol as the eluent. Aliquots of the HPLC fractions were directly analyzed by GC/EI-MS in the selected ion monitoring mode. Data analysis and visualization were performed by the creation of a two dimensional (2D) contour plot, in which GC retention times were plotted against the HPLC fractions. Inspection of the plot resulted in the detection of 133 different fatty acids but only 16 of them contributed more than 1% to the total fatty acids detected. Identification was based on HPLC and GC retention data, GC/MS-SIM and full scan data, as well as plotting the logarithmic retention times against the longest straight carbon chain. In selected cases, aliquots of the HPLC fractions were hydrogenated or studied by means of the picolinyl esters. Using these techniques, the number of double bonds could be unequivocally assigned to all fatty acids. Moreover, the number of methyl branches, and in many cases the positions of methyl branches could be determined. The enantioselective analysis of chiral anteiso-fatty acids resulted in the dominance of the S-enantiomers. However, high proportions of R-a13:0, R-a15:0, and R-a17:1 were also detected while a17:0 was virtually S-enantiopure. Copyright © 2010 Elsevier B.V. All rights reserved.

A facile approach for cupric ion detection in aqueous media using polyethyleneimine/PMMA core-shell fluorescent nanoparticles

NASA Astrophysics Data System (ADS)

Chen, Jian; Zeng, Fang; Wu, Shuizhu; Su, Junhua; Zhao, Jianqing; Tong, Zhen

2009-09-01

A facile approach was developed to produce a dye-doped core-shell nanoparticle chemosensor for detecting Cu2+ in aqueous media. The core-shell nanoparticle sensor was prepared by a one-step emulsifier-free polymerization, followed by the doping of the fluorescent dye Nile red (9-diethylamino- 5H-benzo[alpha] phenoxazine-5-one, NR) into the particles. For the nanoparticles, the hydrophilic polyethyleneimine (PEI) chain segments serve as the shell and the hydrophobic polymethyl methacrylate (PMMA) constitutes the core of the nanoparticles. The non-toxic and biocompatible PEI chain segments on the nanoparticle surface exhibit a high affinity for Cu2+ ions in aqueous media, and the quenching of the NR fluorescence is observed upon binding of Cu2+ ions. This makes the core-shell nanoparticle system a water-dispersible chemosensor for Cu2+ ion detection. The quenching of fluorescence arises through intraparticle energy transfer (FRET) from the dye in the hydrophobic PMMA core to the Cu2+/PEI complexes on the nanoparticle surface. The energy transfer efficiency for PEI/PMMA particles with different diameters was determined, and it is found that the smaller nanoparticle sample exhibits higher quenching efficiency, and the limit for Cu2+ detection is 1 µM for a nanoparticle sample with a diameter of ~30 nm. The response of the fluorescent nanoparticle towards different metal ions was investigated and the nanoparticle chemosensor displays high selectivity and antidisturbance for the Cu2+ ion among the metal ions examined (Na+, K+, Mg2+, Ca2+, Zn2+, Hg2+, Mn2+, Fe2+, Ni2+, Co2+ and Pb2+). This emulsifier-free, biocompatible and sensitive fluorescent nanoparticle sensor may find applications in cupric ion detection in the biological and environmental areas.

A facile approach for cupric ion detection in aqueous media using polyethyleneimine/PMMA core-shell fluorescent nanoparticles.

PubMed

Chen, Jian; Zeng, Fang; Wu, Shuizhu; Su, Junhua; Zhao, Jianqing; Tong, Zhen

2009-09-09

A facile approach was developed to produce a dye-doped core-shell nanoparticle chemosensor for detecting Cu(2+) in aqueous media. The core-shell nanoparticle sensor was prepared by a one-step emulsifier-free polymerization, followed by the doping of the fluorescent dye Nile red (9-diethylamino- 5H-benzo[alpha] phenoxazine-5-one, NR) into the particles. For the nanoparticles, the hydrophilic polyethyleneimine (PEI) chain segments serve as the shell and the hydrophobic polymethyl methacrylate (PMMA) constitutes the core of the nanoparticles. The non-toxic and biocompatible PEI chain segments on the nanoparticle surface exhibit a high affinity for Cu(2+) ions in aqueous media, and the quenching of the NR fluorescence is observed upon binding of Cu(2+) ions. This makes the core-shell nanoparticle system a water-dispersible chemosensor for Cu(2+) ion detection. The quenching of fluorescence arises through intraparticle energy transfer (FRET) from the dye in the hydrophobic PMMA core to the Cu(2+)/PEI complexes on the nanoparticle surface. The energy transfer efficiency for PEI/PMMA particles with different diameters was determined, and it is found that the smaller nanoparticle sample exhibits higher quenching efficiency, and the limit for Cu(2+) detection is 1 microM for a nanoparticle sample with a diameter of approximately 30 nm. The response of the fluorescent nanoparticle towards different metal ions was investigated and the nanoparticle chemosensor displays high selectivity and antidisturbance for the Cu(2+) ion among the metal ions examined (Na(+), K(+), Mg(2+), Ca(2+), Zn(2+), Hg(2+), Mn(2+), Fe(2+), Ni(2+), Co(2+) and Pb(2+)). This emulsifier-free, biocompatible and sensitive fluorescent nanoparticle sensor may find applications in cupric ion detection in the biological and environmental areas.

Ring Resonator for Detection of Melting Brine Under Shallow Subsurface of Mars

NASA Technical Reports Server (NTRS)

Ponchak, George E.; Jordan, Jennifer L.; Scardelletti, Maximillian C.

2016-01-01

Laboratory experimental evidence using Raman spectroscopy has shown that liquid brine may form below the shallow subsurface of Mars. A simpler experimental method to verify the presence of liquid brine or liquid water below Mars surface is needed. In this paper, a ring resonator is used to detect the phase change between frozen water and liquid water below a sandy soil that simulates the Mars surface. Experimental data shows that the ring resonator can detect the melting of thin layers of frozen brine or water up to 15 mm below the surface.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Guohui; Qafoku, Nikolla; Lawter, Amanda R.

A series of batch and column experiments combined with solid phase characterization studies (i.e., quantitative x-ray diffraction and wet chemical extractions) were conducted to address a variety of scientific issues and evaluate the impacts of the potential leakage of carbon dioxide (CO2) from deep subsurface storage reservoirs. The main objective was to gain an understanding of how CO2 gas influences: 1) the aqueous phase pH; and 2) mobilization of major, minor, and trace elements from minerals present in an aquifer overlying potential CO2 sequestration subsurface repositories. Rocks and slightly weathered rocks representative of an unconfined, oxidizing carbonate aquifer within themore » continental US, i.e., the Edwards aquifer in Texas, were used in these studies. These materials were exposed to a CO2 gas stream or were leached with a CO2-saturated influent solution to simulate different CO2 gas leakage scenarios, and changes in aqueous phase pH and chemical composition were measured in the liquid samples collected at pre-determined experimental times (batch experiments) or continuously (column experiments). The results from the strong acid extraction tests confirmed that in addition to the usual elements present in most soils, rocks, and sediments, the Edward aquifer samples contain As, Cd, Pb, Cu, and occasionally Zn, which may potentially be mobilized from the solid to the aqueous phase during or after exposure to CO2. The results from the batch and column experiments confirmed the release of major chemical elements into the contacting aqueous phase (such as Ca, Mg, Ba, Sr, Si, Na, and K); the mobilization and possible rapid immobilization of minor elements (such as Fe, Al, and Mn), which are able to form highly reactive secondary phases; and sporadic mobilization of only low concentrations of trace elements (such as As, Cd, Pb, Cu, Zn, Mo, etc.). The results from this experimental research effort will help in developing a systematic understanding of how CO2 leakage is likely to influence pertinent geochemical processes (e.g., dissolution/precipitation, sorption/desorption) in the aquifer sediments and will support site selection, risk assessment, policy-making, and public education efforts associated with geologic carbon sequestration.« less

Computational sciences in the upstream oil and gas industry

PubMed Central

Halsey, Thomas C.

2016-01-01

The predominant technical challenge of the upstream oil and gas industry has always been the fundamental uncertainty of the subsurface from which it produces hydrocarbon fluids. The subsurface can be detected remotely by, for example, seismic waves, or it can be penetrated and studied in the extremely limited vicinity of wells. Inevitably, a great deal of uncertainty remains. Computational sciences have been a key avenue to reduce and manage this uncertainty. In this review, we discuss at a relatively non-technical level the current state of three applications of computational sciences in the industry. The first of these is seismic imaging, which is currently being revolutionized by the emergence of full wavefield inversion, enabled by algorithmic advances and petascale computing. The second is reservoir simulation, also being advanced through the use of modern highly parallel computing architectures. Finally, we comment on the role of data analytics in the upstream industry. This article is part of the themed issue ‘Energy and the subsurface’. PMID:27597785

Remote Sensing of Subsurface Microbial Transformations

NASA Astrophysics Data System (ADS)

Williams, K. H.; Ntarlagiannis, D.; Slater, L.; Long, P.; Dohnalkova, A.; Hubbard, S. S.; Banfield, J. F.

2004-12-01

Understanding how microorganisms influence the physical and chemical properties of the subsurface is hindered by our inability to detect microbial dynamics in real time with high spatial resolution. Here we have used non-invasive geophysical methods to monitor biomineralization and related processes during biostimulation at both laboratory and field scales. Alterations in saturated sediment characteristics resulting from microbe-mediated transformations were concomitant with changes in complex resistivity, spontaneous potential, and acoustic wave signatures. Variability in complex resistivity and acoustic wave amplitudes appears tied to the nucleation, growth, and development of nanoparticulate precipitates along grain surfaces and within the pore space. In contrast, time-varying spontaneous potentials appear primarily sensitive to the electrochemical gradients resulting from metabolic pathways, such as iron- and sulfate-reduction. Furthermore, they enable us to track mobile fronts of active respiration that arise due to microbial chemotaxis. In this way, geophysical data may be used to image the distribution of mineral precipitates, biomass, and biogeochemical fronts evolving over time and suggest the ability to remotely monitor contaminated aquifers undergoing bioremediation.

Sorption of Pseudomonas putida onto differently structured kaolinite minerals

NASA Astrophysics Data System (ADS)

Vasiliadou, I. A.; Papoulis, D.; Chrysikopoulos, C.; Panagiotaras, D.; Karakosta, E.; Fardis, M.; Papavassiliou, G.

2010-12-01

The presence of bio-colloids (e.g. bacteria and viruses) in the subsurface could be attributed to the release of particles from septic tanks, broken sewer lines or from artificial recharge with treated municipal wastewater. Bio-colloid transport in the subsurface is significantly affected by sorption onto the solid matrix. Bio-colloid attachment onto mobile or suspended in the aqueous phase soil particles (e.g. clay or other minerals) also may influence their fate and transport in the subsurface. The present study focuses on the investigation of Pseudomonas (Ps.) putida sorption onto well (KGa-1) and poorly (KGa-2) crystallized kaolinite minerals. Batch experiments were carried out to determine the sorption isotherms of Ps. putida onto both types of kaolinite particles. The sorption process of Ps. putida onto KGa-1 and KGa-2 is adequately described by a Langmuir isotherm. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy as well as Nuclear Magnetic Resonance were employed to study the sorption mechanisms of Ps. putida. Experimental results indicated that KGa-2 presented higher affinity and sorption capacity than KGa-1. It was shown that electrostatic interactions and structural disorders can influence the sorption capacity of clay particles.

Nematoda from the terrestrial deep subsurface of South Africa.

PubMed

Borgonie, G; García-Moyano, A; Litthauer, D; Bert, W; Bester, A; van Heerden, E; Möller, C; Erasmus, M; Onstott, T C

2011-06-02

Since its discovery over two decades ago, the deep subsurface biosphere has been considered to be the realm of single-cell organisms, extending over three kilometres into the Earth's crust and comprising a significant fraction of the global biosphere. The constraints of temperature, energy, dioxygen and space seemed to preclude the possibility of more-complex, multicellular organisms from surviving at these depths. Here we report species of the phylum Nematoda that have been detected in or recovered from 0.9-3.6-kilometre-deep fracture water in the deep mines of South Africa but have not been detected in the mining water. These subsurface nematodes, including a new species, Halicephalobus mephisto, tolerate high temperature, reproduce asexually and preferentially feed upon subsurface bacteria. Carbon-14 data indicate that the fracture water in which the nematodes reside is 3,000-12,000-year-old palaeometeoric water. Our data suggest that nematodes should be found in other deep hypoxic settings where temperature permits, and that they may control the microbial population density by grazing on fracture surface biofilm patches. Our results expand the known metazoan biosphere and demonstrate that deep ecosystems are more complex than previously accepted. The discovery of multicellular life in the deep subsurface of the Earth also has important implications for the search for subsurface life on other planets in our Solar System.

Electrical double layer modulation of hybrid room temperature ionic liquid/aqueous buffer interface for enhanced sweat based biosensing.

PubMed

Jagannath, Badrinath; Muthukumar, Sriram; Prasad, Shalini

2018-08-03

We have investigated the role of kosmotropic anionic moieties and chaotropic cationic moieties of room temperature hydrophilic ionic liquids in enhancing the biosensing performance of affinity based immunochemical biosensors in human sweat. Two ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM[BF 4 ]) and choline dihydrogen phosphate (Choline[DHP]) were investigated in this study with Choline[DHP] being more kosmotropic in nature having a more protein stabilizing effect based on the hofmeister series. Non-faradaic interfacial charge transfer has been employed as the mechanism for evaluating the formation and the biosensing of capture probe antibodies in room temperature ionic liquids (RTILs)/aqueous human sweat interface. The charge of the ionic moieties were utilized to form compact electrical double layers around the antibodies for enhancing the stability of the antibody capture probes, which was evaluated through zeta potential measurements. The zeta potential measurements indicated stability of antibodies due to electrostatic repulsion of the RTIL charged moieties encompassing the antibodies, thus preventing any aggregation. Here, we report for the first time of non-faradaic electrochemical impedance spectroscopy equivalent circuit model analysis for analyzing and interpreting affinity based biosensing at hybrid electrode/ionic liquid-aqueous sweat buffer interface guided by the choice of the ionic liquid. Interleukin-6 (IL-6) and cortisol two commonly occurring biomarkers in human sweat were evaluated using this method. The limit of detection (LOD) obtained using both ionic liquids for IL-6 was 0.2 pg mL -1 with cross-reactivity studies indicating better performance of IL-6 detection using Choline[DHP] and no response to cross-reactive molecule. The LOD of 0.1 ng/mL was achieved for cortisol and the cross-reactivity studies indicated that cortisol antibody in BMIM[BF 4 ] did not show any signal response to cross-reactive molecules. Furthermore, improved sensitivity and LOD was achieved using ionic liquids as compared to capture probes in aqueous buffer. Copyright © 2018 Elsevier B.V. All rights reserved.

Hypoglycemic effect of Carica papaya leaves in streptozotocin-induced diabetic rats

PubMed Central

2012-01-01

Background Traditional plant treatment for diabetes has shown a surging interest in the last few decades. Therefore, the purpose of this study was to assess the hypoglycemic effect of the aqueous extract of C. papaya leaves in diabetic rats. Several studies have reported that some parts of the C. papaya plant exert hypoglycemic effects in both animals and humans. Methods Diabetes was induced in rats by intraperitoneal administration of 60 mg/kg of streptozotocin (STZ). The aqueous extract of C. papaya was administered in three different doses (0.75, 1.5 and 3 g/100 mL) as drinking water to both diabetic and non-diabetic animals during 4 weeks. Results The aqueous extract of Carica papaya (0.75 g and 1.5 g/100 mL) significantly decreased blood glucose levels (p<0.05) in diabetic rats. It also decreased cholesterol, triacylglycerol and amino-transferases blood levels. Low plasma insulin levels did not change after treatment in diabetic rats, but they significantly increased in non-diabetic animals. Pancreatic islet cells were normal in non-diabetic treated animals, whereas in diabetic treated rats, C. papaya could help islet regeneration manifested as preservation of cell size. In the liver of diabetic treated rats, C. papaya prevented hepatocyte disruption, as well as accumulation of glycogen and lipids. Finally, an antioxidant effect of C. papaya extract was also detected in diabetic rats. Conclusions This study showed that the aqueous extract of C. papaya exerted a hypoglycemic and antioxidant effect; it also improved the lipid profile in diabetic rats. In addition, the leaf extract positively affected integrity and function of both liver and pancreas. PMID:23190471

Boron compounds as anion binding agents for nonaqueous battery electrolytes

DOEpatents

Lee, Hung Sui; Yang, Xia-Oing; McBreen, James; Xiang, Caili

2000-02-08

Novel fluorinated boron-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boron-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boron-based anion receptors include borane and borate compounds bearing different fluorinated alkyl and aryl groups.

Detecting a subsurface cylinder by a Time Reversal MUSIC like method

NASA Astrophysics Data System (ADS)

Solimene, Raffaele; Dell'Aversano, Angela; Leone, Giovanni

2014-05-01

In this contribution the problem of imaging a buried homogeneous circular cylinder is dealt with for a two-dimensional scalar geometry. Though the addressed geometry is extremely simple as compared to real world scenarios, it can be considered of interest for a classical GPR civil engineering applicative context: that is the subsurface prospecting of urban area in order to detect and locate buried utilities. A large body of methods for subsurface imaging have been presented in literature [1], ranging from migration algorithms to non-linear inverse scattering approaches. More recently, also spectral estimation methods, which benefit from sub-array data arrangement, have been proposed and compared in [2].Here a Time Reversal MUSIC (TRM) like method is employed. TRM has been initially conceived to detect point-like scatterers and then generalized to the case of extended scatterers [3]. In the latter case, no a priori information about the scatterers is exploited. However, utilities often can be schematized as circular cylinders. Here, we develop a TRM variant which use this information to properly tailor the steering vector while implementing TRM. Accordingly, instead of a spatial map [3], the imaging procedure returns the scatterer's parameters such as its center position, radius and dielectric permittivity. The study is developed by numerical simulations. First the free-space case is considered in order to more easily introduce the idea and the problem mathematical structure. Then the analysis is extended to the half-space case. In both situations a FDTD forward solver is used to generate the synthetic data. As usual in TRM, a multi-view/multi-static single-frequency configuration is considered and emphasis is put on the role played by the number of available sensors. Acknowledgement This work benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar." [1] A. Randazzo and R. Solimene, 'Development Of New Methods For The Solution Of Inverse Electromagnetic Scattering Problems By Buried Structures: State of the Art and Open Issues ,'in COST ACTION TU1208: CIVIL ENGINEERING APPLICATIONS OF GROUND PENETRATING RADAR, Proceedings of first Action's General Meeting, 2013. ISBN: 978-88-548-6191-6. [2] S. Meschino, L. Pajewski, M. Pastorino, A. Randazzo, G. Schettini, "Detection of subsurface metallic utilities by means of a SAP technique: Comparing MUSIC- and SVM-based approaches, Journal of Applied Geophysics, vol. 97, pp. 60-68, 2013. [3] E. A. Marengo, F. K. Gruber, F. Simonetti, 'Time-reversal MUSIC imaging of extended targets,' IEEE Trans Image Process. vol. 16, pp. 1967-84, 2007

Nde of Frp Wrapped Columns Using Infrared Thermography

NASA Astrophysics Data System (ADS)

Halabe, Udaya B.; Dutta, Shasanka Shekhar; GangaRao, Hota V. S.

2008-02-01

This paper investigates the feasibility of using Infrared Thermography (IRT) for detecting debonds in Fiber Reinforced Polymer (FRP) wrapped columns. Laboratory tests were conducted on FRP wrapped concrete cylinders of size 6″×12″ (152.4 mm×304.8 mm) in which air-filled and water-filled debonds of various sizes were placed underneath the FRP wraps. Air-filled debonds were made by cutting plastic sheets into the desired sizes whereas water-filled debonds were made by filling water in custom made polyethylene pouches. Both carbon and glass fiber reinforced wraps were considered in this study. Infrared tests were conducted using a fully radiometric digital infrared camera which was successful in detecting air-filled as well as water-filled subsurface debonds. In addition to the laboratory testing, two field trips were made to Moorefield, West Virginia for detecting subsurface debonds in FRP wrapped timber piles of a railroad bridge using infrared testing. The results revealed that infrared thermography can be used as an effective nondestructive evaluation tool for detecting subsurface debonds in structural components wrapped with carbon or glass reinforced composite fabrics.

Coupling Aggressive Mass Removal with Microbial Reductive Dechlorination for Remediation of DNAPL Source Zones: A Review and Assessment

PubMed Central

Christ, John A.; Ramsburg, C. Andrew; Abriola, Linda M.; Pennell, Kurt D.; Löffler, Frank E.

2005-01-01

The infiltration of dense non-aqueous-phase liquids (DNAPLs) into the saturated subsurface typically produces a highly contaminated zone that serves as a long-term source of dissolved-phase groundwater contamination. Applications of aggressive physical–chemical technologies to such source zones may remove > 90% of the contaminant mass under favorable conditions. The remaining contaminant mass, however, can create a rebounding of aqueous-phase concentrations within the treated zone. Stimulation of microbial reductive dechlorination within the source zone after aggressive mass removal has recently been proposed as a promising staged-treatment remediation technology for transforming the remaining contaminant mass. This article reviews available laboratory and field evidence that supports the development of a treatment strategy that combines aggressive source-zone removal technologies with subsequent promotion of sustained microbial reductive dechlorination. Physical–chemical source-zone treatment technologies compatible with posttreatment stimulation of microbial activity are identified, and studies examining the requirements and controls (i.e., limits) of reductive dechlorination of chlorinated ethenes are investigated. Illustrative calculations are presented to explore the potential effects of source-zone management alternatives. Results suggest that, for the favorable conditions assumed in these calculations (i.e., statistical homogeneity of aquifer properties, known source-zone DNAPL distribution, and successful bioenhancement in the source zone), source longevity may be reduced by as much as an order of magnitude when physical–chemical source-zone treatment is coupled with reductive dechlorination. PMID:15811838

Using dynamic flux chambers to estimate the natural attenuation rates in the subsurface at petroleum contaminated sites.

PubMed

Verginelli, Iason; Pecoraro, Roberto; Baciocchi, Renato

2018-04-01

In this work, we introduce a screening method for the evaluation of the natural attenuation rates in the subsurface at sites contaminated by petroleum hydrocarbons. The method is based on the combination of the data obtained from standard source characterization with dynamic flux chambers measurements. The natural attenuation rates are calculated as difference between the flux of contaminants estimated with a non-reactive diffusive model starting from the concentrations of the contaminants detected in the source (soil and/or groundwater) and the effective emission rate of the contaminants measured using dynamic flux chambers installed at ground level. The reliability of this approach was tested in a contaminated site characterized by the presence of BTEX in soil and groundwater. Namely, the BTEX emission rates from the subsurface were measured in 4 seasonal campaigns using dynamic flux chambers installed in 14 sampling points. The comparison of measured fluxes with those predicted using a non-reactive diffusive model, starting from the source concentrations, showed that, in line with other recent studies, the modelling approach can overestimate the expected outdoor concentration of petroleum hydrocarbons even up to 4 orders of magnitude. On the other hand, by coupling the measured data with the fluxes estimated with the diffusive non-reactive model, it was possible to perform a mass balance to evaluate the natural attenuation loss rates of petroleum hydrocarbons during the migration from the source to ground level. Based on this comparison, the estimated BTEX loss rates in the test site were up to almost 0.5kg/year/m 2 . These rates are in line with the values reported in the recent literature for natural source zone depletion. In short, the method presented in this work can represent an easy-to-use and cost-effective option that can provide a further line of evidence of natural attenuation rates expected at contaminated sites. Copyright © 2017 Elsevier B.V. All rights reserved.

Precise ruthenium fission product isotopic analysis using dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Christopher F.; Dresel, P. Evan; Geiszler, Keith N.

2006-05-09

99Tc is a subsurface contaminant of interest at numerous federal, industrial, and international facilities. However, as a mono-isotopic fission product, 99Tc lacks the ability to be used as a signature to differentiate between the different waste disposal pathways that could have contributed to subsurface contamination at these facilities. Ruthenium fission-product isotopes are attractive analogues for the characterization of 99Tc sources because of their direct similarity to technetium with regard to subsurface mobility, and their large fission yields and low natural background concentrations. We developed an inductively coupled plasma mass spectrometry (ICP-MS) method capable of measuring ruthenium isotopes in groundwater samplesmore » and extracts of vadose zone sediments. Samples were analyzed directly on a Perkin Elmer ELAN DRC II ICP-MS after a single pass through a 1-ml bed volume of Dowex AG 50W-X8 100-200 mesh cation exchange resin. Precise ruthenium isotopic ratio measurements were achieved using a low-flow Meinhard-type nebulizer and long sample acquisition times (150,000 ms). Relative standard deviations of triplicate replicates were maintained at less than 0.5% when the total ruthenium solution concentration was 0.1 ng/ml or higher. Further work was performed to minimize the impact caused by mass interferences using the dynamic reaction cell (DRC) with O2 as the reaction gas. The aqueous concentrations of 96Mo and 96Zr were reduced by more than 99.7% in the reaction cell prior to injection of the sample into the mass analyzer quadrupole. The DRC was used in combination with stable-mass correction to quantitatively analyze samples containing up to 2-orders of magnitude more zirconium and molybdenum than ruthenium. The analytical approach documented herein provides an efficient and cost-effective way to precisely measure ruthenium isotopes and quantitate total ruthenium (natural vs. fission-product) in aqueous matrixes.« less

Advanced Algorithms and High-Performance Testbed for Large-Scale Site Characterization and Subsurface Target Detecting Using Airborne Ground Penetrating SAR

NASA Technical Reports Server (NTRS)

Fijany, Amir; Collier, James B.; Citak, Ari

1997-01-01

A team of US Army Corps of Engineers, Omaha District and Engineering and Support Center, Huntsville, let Propulsion Laboratory (JPL), Stanford Research Institute (SRI), and Montgomery Watson is currently in the process of planning and conducting the largest ever survey at the Former Buckley Field (60,000 acres), in Colorado, by using SRI airborne, ground penetrating, Synthetic Aperture Radar (SAR). The purpose of this survey is the detection of surface and subsurface Unexploded Ordnance (UXO) and in a broader sense the site characterization for identification of contaminated as well as clear areas. In preparation for such a large-scale survey, JPL has been developing advanced algorithms and a high-performance restbed for processing of massive amount of expected SAR data from this site. Two key requirements of this project are the accuracy (in terms of UXO detection) and speed of SAR data processing. The first key feature of this testbed is a large degree of automation and a minimum degree of the need for human perception in the processing to achieve an acceptable processing rate of several hundred acres per day. For accurate UXO detection, novel algorithms have been developed and implemented. These algorithms analyze dual polarized (HH and VV) SAR data. They are based on the correlation of HH and VV SAR data and involve a rather large set of parameters for accurate detection of UXO. For each specific site, this set of parameters can be optimized by using ground truth data (i.e., known surface and subsurface UXOs). In this paper, we discuss these algorithms and their successful application for detection of surface and subsurface anti-tank mines by using a data set from Yuma proving Ground, A7, acquired by SRI SAR.

Integration of P- and SH-wave high-resolution seismic reflection and micro-gravity techniques to improve interpretation of shallow subsurface structure: New Madrid seismic zone

USGS Publications Warehouse

Bexfield, C.E.; McBride, J.H.; Pugin, Andre J.M.; Ravat, D.; Biswas, S.; Nelson, W.J.; Larson, T.H.; Sargent, S.L.; Fillerup, M.A.; Tingey, B.E.; Wald, L.; Northcott, M.L.; South, J.V.; Okure, M.S.; Chandler, M.R.

2006-01-01

Shallow high-resolution seismic reflection surveys have traditionally been restricted to either compressional (P) or horizontally polarized shear (SH) waves in order to produce 2-D images of subsurface structure. The northernmost Mississippi embayment and coincident New Madrid seismic zone (NMSZ) provide an ideal laboratory to study the experimental use of integrating P- and SH-wave seismic profiles, integrated, where practicable, with micro-gravity data. In this area, the relation between "deeper" deformation of Paleozoic bedrock associated with the formation of the Reelfoot rift and NMSZ seismicity and "shallower" deformation of overlying sediments has remained elusive, but could be revealed using integrated P- and SH-wave reflection. Surface expressions of deformation are almost non-existent in this region, which makes seismic reflection surveying the only means of detecting structures that are possibly pertinent to seismic hazard assessment. Since P- and SH-waves respond differently to the rock and fluid properties and travel at dissimilar speeds, the resulting seismic profiles provide complementary views of the subsurface based on different levels of resolution and imaging capability. P-wave profiles acquired in southwestern Illinois and western Kentucky (USA) detect faulting of deep, Paleozoic bedrock and Cretaceous reflectors while coincident SH-wave surveys show that this deformation propagates higher into overlying Tertiary and Quaternary strata. Forward modeling of micro-gravity data acquired along one of the seismic profiles further supports an interpretation of faulting of bedrock and Cretaceous strata. The integration of the two seismic and the micro-gravity methods therefore increases the scope for investigating the relation between the older and younger deformation in an area of critical seismic hazard. ?? 2006 Elsevier B.V. All rights reserved.

Genetic and functional properties of uncultivated thermophilic crenarchaeotes from a subsurface gold mine as revealed by analysis of genome fragments.

PubMed

Nunoura, Takuro; Hirayama, Hisako; Takami, Hideto; Oida, Hanako; Nishi, Shinro; Shimamura, Shigeru; Suzuki, Yohey; Inagaki, Fumio; Takai, Ken; Nealson, Kenneth H; Horikoshi, Koki

2005-12-01

Within a phylum Crenarchaeota, only some members of the hyperthermophilic class Thermoprotei, have been cultivated and characterized. In this study, we have constructed a metagenomic library from a microbial mat formation in a subsurface hot water stream of the Hishikari gold mine, Japan, and sequenced genome fragments of two different phylogroups of uncultivated thermophilic Crenarchaeota: (i) hot water crenarchaeotic group (HWCG) I (41.2 kb), and (ii) HWCG III (49.3 kb). The genome fragment of HWCG I contained a 16S rRNA gene, two tRNA genes and 35 genes encoding proteins but no 23S rRNA gene. Among the genes encoding proteins, several genes for putative aerobic-type carbon monoxide dehydrogenase represented a potential clue with regard to the yet unknown metabolism of HWCG I Archaea. The genome fragment of HWCG III contained a 16S/23S rRNA operon and 44 genes encoding proteins. In the 23S rRNA gene, we detected a homing-endonuclease encoding a group I intron similar to those detected in hyperthermophilic Crenarchaeota and Bacteria, as well as eukaryotic organelles. The reconstructed phylogenetic tree based on the 23S rRNA gene sequence reinforced the intermediate phylogenetic affiliation of HWCG III bridging the hyperthermophilic and non-thermophilic uncultivated Crenarchaeota.

Time- and angle-resolved photoemission spectroscopy of hydrated electrons near a liquid water surface.

PubMed

Yamamoto, Yo-ichi; Suzuki, Yoshi-Ichi; Tomasello, Gaia; Horio, Takuya; Karashima, Shutaro; Mitríc, Roland; Suzuki, Toshinori

2014-05-09

We present time- and angle-resolved photoemission spectroscopy of trapped electrons near liquid surfaces. Photoemission from the ground state of a hydrated electron at 260 nm is found to be isotropic, while anisotropic photoemission is observed for the excited states of 1,4-diazabicyclo[2,2,2]octane and I- in aqueous solutions. Our results indicate that surface and subsurface species create hydrated electrons in the bulk side. No signature of a surface-bound electron has been observed.

SPECIATION OF SUBSURFACE CONTAMINANTS BY CONE PENETROMETRY GAS CHROMATOGRAPHY/MASS SPECTROMETRY. (R826184)

EPA Science Inventory

A thermal extraction cone penetrometry gas chroma tography/mass spectrometry system (TECP GC/MS) has been developed to detect subsurface contaminants in situ. The TECP can collect soil-bound organics up to depths of 30 m. In contrast to traditional cone penetrometer sample collec...

SUBSURFACE CHARACTERIZATION AND MONITORING TECHNIQUES: A DESK REFERENCE GUIDE - VOLUME I: SOLIDS AND GROUND WATER - APPENDICES A AND B

EPA Science Inventory

Many EPA programs, including those under the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Response, Compensation, and Liability Act (CERCLA), require subsurface characterization and monitoring to detect ground-water contamination and provide data to devel...

Evaluating time-lapse ERT for monitoring DNAPL remediation via numerical simulation

NASA Astrophysics Data System (ADS)

Power, C.; Karaoulis, M.; Gerhard, J.; Tsourlos, P.; Giannopoulos, A.

2012-12-01

Dense non-aqueous phase liquids (DNAPLs) remain a challenging geoenvironmental problem in the near subsurface. Numerous thermal, chemical, and biological treatment methods are being applied at sites but without a non-destructive, rapid technique to map the evolution of DNAPL mass in space and time, the degree of remedial success is difficult to quantify. Electrical resistivity tomography (ERT) has long been presented as highly promising in this context but has not yet become a practitioner's tool due to challenges in interpreting the survey results at real sites where the initial condition (DNAPL mass, DNAPL distribution, subsurface heterogeneity) is typically unknown. Recently, a new numerical model was presented that couples DNAPL and ERT simulation at the field scale, providing a tool for optimizing ERT application and interpretation at DNAPL sites (Power et al., 2011, Fall AGU, H31D-1191). The objective of this study is to employ this tool to evaluate the effectiveness of time-lapse ERT to monitor DNAPL source zone remediation, taking advantage of new inversion methodologies that exploit the differences in the target over time. Several three-dimensional releases of chlorinated solvent DNAPLs into heterogeneous clayey sand at the field scale were generated, varying in the depth and complexity of the source zone (target). Over time, dissolution of the DNAPL in groundwater was simulated with simultaneous mapping via periodic ERT surveys. Both surface and borehole ERT surveys were conducted for comparison purposes. The latest four-dimensional ERT inversion algorithms were employed to generate time-lapse isosurfaces of the DNAPL source zone for all cases. This methodology provided a qualitative assessment of the ability of ERT to track DNAPL mass removal for complex source zones in realistically heterogeneous environments. In addition, it provided a quantitative comparison between the actual DNAPL mass removed and that interpreted by ERT as a function of depth below the water table, as well as an estimate of the minimum DNAPL saturation changes necessary for an observable response from ERT.

Aqueous levels of erythropoietin in acute retinal vein occlusion with macular edema

PubMed Central

Shin, Hyun Jin; Kim, Hyung Chan; Moon, Jun Woong

2014-01-01

AIM To investigate the aqueous erythropoietin (EPO) levels and associated factors in patients with acute retinal vein occlusion (RVO). METHODS The aqueous EPO level was measured in patients with macular edema (ME) secondary to acute branched retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO). Aqueous fluid from cataract patients served as the control. We also evaluated whether aqueous level of EPO was associated with factors such as serum EPO level, non-perfusion area, central macular thickness (CMT), and arterio-venous (AV) transit time RESULTS Twenty-seven RVO patients (16 BRVO, 11 CRVO) and 9 control subjects were enrolled in the study. The aqueous EPO level (mU/mL) was higher in RVO (68.2±54.3) than that in the control subjects (12.9±5.9). More specifically, the aqueous EPO level was higher in CRVO (118.9±52.1) than that in BRVO (33.3±10.8). However, no differences were found in serum EPO levels among three groups. CMT in RVO patients had a positive correlation with the aqueous EPO level (r=0.66). Also, in terms of non-perfusion area, the aqueous EPO levels were more elevated in the ischemic subgroup than in the non-ischemic subgroup in both BRVO and CRVO. CONCLUSION Aqueous EPO levels are elevated in patients with macular edema secondary to recent onset RVO. Patients with CRVO have higher EPO levels than those with BRVO. The aqueous EPO level in RVO has a positive correlation with CMT and is associated with non-perfusion area. These results suggest that the aqueous EPO level could be associated with retinal ischemia and may be involved in the pathogenesis of macular edema secondary to RVO. PMID:24967199

Synthesis and Evaluation of Aryl Boronic Acids as Fluorescent Artificial Receptors for Biological Carbohydrates

PubMed Central

Craig, Sandra

2011-01-01

Carbohydrates in various forms play a vital role in numerous critical biological processes. The detection of such saccharides can give insight into the progression of such diseases such as cancer. Boronic acids react with 1,2 and 1,3 diols of saccharides in non-aqueous or basic aqueous media. Herein, we describe the design, synthesis and evaluation of three bisboronic acid fluorescent probes, each having about ten linear steps in its synthesis. Among these compounds that were evaluated, 9b was shown to selectively label HepG2, liver carcinoma cell line within a concentration range of 0.5–10 μM in comparison to COS-7, a normal fibroblast cell line. PMID:22177855

A New Optical Scheme for a Polarimetric-Based Glucose Sensor

NASA Technical Reports Server (NTRS)

Ansari, Rafat R.; Boeckle, Stefan; Rovati, Luigi; Salzman, Jack A. (Technical Monitor)

2002-01-01

We describe a new optical scheme to perform polarimetric measurements to detect glucose concentration in the aqueous humor of a model eye. The ultimate aim is to apply this technique in designing a new instrument for measuring glucose levels in diabetic patients routinely, frequently, and non-invasively. The scheme exploits the Brewsterreflection of circularly polarized light off of the lens of the eye. Theoretically, this backreflected linearly polarized light on its way to the detector is expected to rotate its state of polarization due to the presence of glucose molecules in the aqueous humor of patients. An experimental laboratory setup based on this scheme was designed and tested by measuring a range of known concentration of glucose solutions dissolved in water.

Application of morphological associative memories and Fourier descriptors for classification of noisy subsurface signatures

NASA Astrophysics Data System (ADS)

Ortiz, Jorge L.; Parsiani, Hamed; Tolstoy, Leonid

2004-02-01

This paper presents a method for recognition of Noisy Subsurface Images using Morphological Associative Memories (MAM). MAM are type of associative memories that use a new kind of neural networks based in the algebra system known as semi-ring. The operations performed in this algebraic system are highly nonlinear providing additional strength when compared to other transformations. Morphological associative memories are a new kind of neural networks that provide a robust performance with noisy inputs. Two representations of morphological associative memories are used called M and W matrices. M associative memory provides a robust association with input patterns corrupted by dilative random noise, while the W associative matrix performs a robust recognition in patterns corrupted with erosive random noise. The robust performance of MAM is used in combination of the Fourier descriptors for the recognition of underground objects in Ground Penetrating Radar (GPR) images. Multiple 2-D GPR images of a site are made available by NASA-SSC center. The buried objects in these images appear in the form of hyperbolas which are the results of radar backscatter from the artifacts or objects. The Fourier descriptors of the prototype hyperbola-like and shapes from non-hyperbola shapes in the sub-surface images are used to make these shapes scale-, shift-, and rotation-invariant. Typical hyperbola-like and non-hyperbola shapes are used to calculate the morphological associative memories. The trained MAMs are used to process other noisy images to detect the presence of these underground objects. The outputs from the MAM using the noisy patterns may be equal to the training prototypes, providing a positive identification of the artifacts. The results are images with recognized hyperbolas which indicate the presence of buried artifacts. A model using MATLAB has been developed and results are presented.

The emission potential of different land use patterns for the occurrence of coliphages in surface water.

PubMed

Franke, Christiane; Rechenburg, Andrea; Baumanns, Susanne; Willkomm, Marlene; Christoffels, Ekkehard; Exner, Martin; Kistemann, Thomas

2009-05-01

Different land use patterns were investigated for their potential as non-point sources of coliphage emissions into surface waters. Water samples were taken regularly at five locations in the upper reaches of the river Swist, Germany. Samples of surface and subsurface run-off were taken within the same catchment area after rainfall events using a newly developed device that made it possible to collect current concentrations of the effluent compounds. The water quality was examined for the occurrence of somatic coliphages and F(+)-specific RNA-bacteriophages as well as for various bacteria over the period of a hydrological year. The potential of various bacteria as indicators for the occurrence of phages was evaluated using statistical correlations. The load of coliphages varied depending on the land use type, but it did not differ as much as the bacterial parameters. River sections in intensively used areas turned out to be more contaminated than in less intensively used regions. The concentrations of phages from surface and subsurface run-off in most samples were quite low for all land use types and did not show conspicuous variations of surface and subsurface run-off within one land use type. Therefore, high concentrations of phages in river water cannot be explained only by non-point effluent from open ground. Following consideration of the statistical results, conventional indicator bacteria seem not to be reliable indicator organisms for coliphages and subsequently for human pathogen viruses. The detected concentrations of coliphages in several water samples of river sections surrounded by intensively used areas underpin an existing health risk in the use of river water for e.g. recreational activities or irrigation.

Impact of DNAPL Storage in Cracked Low Permeability Layers on Dissolved Contaminant Plume Persistence

NASA Astrophysics Data System (ADS)

Goltz, M. N.; Sievers, K. W.; Huang, J.; Demond, A. H.

2012-12-01

The subsurface storage and transport of a Dense Non-Aqueous Phase Liquid (DNAPL) was evaluated using a numerical model. DNAPLs are organic liquids comprised of slightly water-soluble chemicals or chemical mixtures that have a density greater than water. DNAPLs may pool atop low permeability layers upon entering the subsurface. Even with the removal or destruction of most pooled DNAPL mass, small amounts of the remaining contaminant, which had been transported into the low permeability layer, can dissolve into flowing groundwater and continue to act as a contamination source for decades. Recently developed models assume that transport in the low permeability zones is strictly diffusive; however field observations suggest that more mass is stored in the low permeability zones than can be explained by diffusion alone. Observations and experimental evidence indicate that cracks in low permeability layers may have apertures of sufficient size to allow entry of separate phase DNAPL. In this study, a numerical flow and transport model is employed using a dual domain construct (high and low permeability layers) to investigate the impact of DNAPL entry into cracked low permeability zones on dissolved contaminant plume evolution and persistence. This study found that DNAPL within cracks can significantly contribute to down gradient dissolved phase concentrations; however, the extent of this contribution is very dependent upon the rate of DNAPL dissolution. Given these findings, remediation goals may be difficult to meet if source remediation strategies are used which do not account for the effect of cracking upon contaminant transport and storage in low permeability layers.

An introductory study using impedance spectroscopy technique with polarizable microelectrode for amino acids characterization

NASA Astrophysics Data System (ADS)

Chin, K. B.; Chi, I.; Pasalic, J.; Huang, C.-K.; Barge, Laura M.

2018-04-01

Portable, low power, yet ultra-sensitive life detection instrumentations are vital to future astrobiology flight programs at NASA. In this study, initial attempts to characterize amino acids in an aqueous environment by electrochemical impedance spectroscopy (EIS) using polarizable (blocking) electrodes in order to establish a means of detection via their electrical properties. Seven amino acids were chosen due to their scientific importance in demonstrating sensitivity levels in the range of part per billion concentration. Albeit more challenging in real systems of analyst mixtures, we found individual amino acids in aqueous environment do exhibit some degree of chemical and physical uniqueness to warrant characterization by EIS. The polar amino acids (Asp, Glu, and His) exhibited higher electrochemical activity than the non-polar amino acids (Ala, Gly, Val, and Leu). The non-polar amino acids (Gly and Ala) also exhibited unique electrical properties which appeared to be more dependent on physical characteristics such as molecular weight and structure. At concentrations above 1 mM where the amino acids play a more dominant transport role within the water, the conductivity was found to be more sensitive to concentrations. At lower concentrations <1 mM, however, the polar amino acid solution conductivity remained constant, suggesting poor chemical activity with water. As revealed by equivalent circuit modeling, the relaxation times showed a 1-2 order of magnitude difference between polar and non-polar amino acids. The pseudo-capacitance from EIS measurements on sample mixtures containing salt water and individual amino acids revealed the possibility for improvement in amino acid selectivity using gold nanoporous surface enhanced electrodes. This work establishes important methodologies for characterizing amino acids using EIS combined with microscale electrodes, supporting the case for instrumentation development for life detection and origin of life programs.

An introductory study using impedance spectroscopy technique with polarizable microelectrode for amino acids characterization.

PubMed

Chin, K B; Chi, I; Pasalic, J; Huang, C-K; Barge, Laura M

2018-04-01

Portable, low power, yet ultra-sensitive life detection instrumentations are vital to future astrobiology flight programs at NASA. In this study, initial attempts to characterize amino acids in an aqueous environment by electrochemical impedance spectroscopy (EIS) using polarizable (blocking) electrodes in order to establish a means of detection via their electrical properties. Seven amino acids were chosen due to their scientific importance in demonstrating sensitivity levels in the range of part per billion concentration. Albeit more challenging in real systems of analyst mixtures, we found individual amino acids in aqueous environment do exhibit some degree of chemical and physical uniqueness to warrant characterization by EIS. The polar amino acids (Asp, Glu, and His) exhibited higher electrochemical activity than the non-polar amino acids (Ala, Gly, Val, and Leu). The non-polar amino acids (Gly and Ala) also exhibited unique electrical properties which appeared to be more dependent on physical characteristics such as molecular weight and structure. At concentrations above 1 mM where the amino acids play a more dominant transport role within the water, the conductivity was found to be more sensitive to concentrations. At lower concentrations <1 mM, however, the polar amino acid solution conductivity remained constant, suggesting poor chemical activity with water. As revealed by equivalent circuit modeling, the relaxation times showed a 1-2 order of magnitude difference between polar and non-polar amino acids. The pseudo-capacitance from EIS measurements on sample mixtures containing salt water and individual amino acids revealed the possibility for improvement in amino acid selectivity using gold nanoporous surface enhanced electrodes. This work establishes important methodologies for characterizing amino acids using EIS combined with microscale electrodes, supporting the case for instrumentation development for life detection and origin of life programs.

Remotely Exploring Deeper-Into-Matter by Non-Contact Detection of Audible Transients Excited by Laser Radiation

PubMed Central

Moros, Javier; Gaona, Inmaculada; Laserna, J. Javier

2017-01-01

An acoustic spectroscopic approach to detect contents within different packaging, with substantially wider applicability than other currently available subsurface spectroscopies, is presented. A frequency-doubled Nd:YAG (neodymium-doped yttrium aluminum garnet) pulsed laser (13 ns pulse length) operated at 1 Hz was used to generate the sound field of a two-component system at a distance of 50 cm. The acoustic emission was captured using a unidirectional microphone and analyzed in the frequency domain. The focused laser pulse hitting the system, with intensity above that necessary to ablate the irradiated surface, transferred an impulsive force which led the structure to vibrate. Acoustic airborne transients were directly radiated by the vibrating elastic structure of the outer component that excited the surrounding air in contact with. However, under boundary conditions, sound field is modulated by the inner component that modified the dynamical integrity of the system. Thus, the resulting frequency spectra are useful indicators of the concealed content that influences the contributions originating from the wall of the container. High-quality acoustic spectra could be recorded from a gas (air), liquid (water), and solid (sand) placed inside opaque chemical-resistant polypropylene and stainless steel sample containers. Discussion about effects of laser excitation energy and sampling position on the acoustic emission events is reported. Acoustic spectroscopy may complement the other subsurface alternative spectroscopies, severely limited by their inherent optical requirements for numerous detection scenarios. PMID:29261126

Non-aqueous capillary electrophoretic separation of cholesterol and 25-hydroxycholesterol after derivatization with Girard P reagent.

PubMed

Gregus, Michal; Roberg-Larsen, Hanne; Lundanes, Elsa; Foret, Frantisek; Kuban, Petr; Wilson, Steven Ray

2017-10-01

Capillary electrophoresis (CE) can provide high separation efficiency with very simple instrumentation, but has yet to be explored regarding oxysterols/cholesterol. Cholesterol and 25-hydroxycholesterol (both are 4-ene-3-ketosteroids) were quantitatively transformed into hydrazones using Girard P reagent after enzymatic oxidation by cholesterol oxidase. Separation was achieved using non-aqueous capillary electrophoresis with UV detection at 280nm; the "charge-tagging" Girard P reagent ensured both charge and chromophore (which are requirements for CE-UV). Excess reagent was also separated from the two analytes, eliminating the need for removal prior to the analysis. The compounds were separated in less than 5min with excellent separation efficiency, using separation electrolytes fully compatible with mass spectrometry. The CE-UV method was used to optimize steps for charge-tagging, revealing that the procedure is affected by the analyte/reagent ratio and reaction time, but also the analyte structure. Copyright © 2017 Elsevier B.V. All rights reserved.

Spatial distribution of jet fuel in the vadoze zone of a heterogeneous and fractured soil.

PubMed

Tzovolou, D N; Benoit, Y; Haeseler, F; Klint, K E; Tsakiroglou, C D

2009-04-01

The goal of the present work is to screen and evaluate all available data before selecting and testing remediation technologies on heterogeneous soils polluted by jet fuel. The migration pathways of non-aqueous phase liquids (NAPLs) in the subsurface relate closely with soil properties. A case study is performed on the vadoze zone of a military airport of north-west Poland contaminated by jet fuel. Soil samples are collected from various depths of two cells, and on-site and off-site chemical analyses of hydrocarbons are conducted by using Pollut Eval apparatus and GC-MS, respectively. The geological conceptual model of the site along with microscopic and hydraulic properties of the porous matrix and fractures enable us to interpret the non-uniform spatial distribution of jet fuel constituents. The total concentration of the jet fuel and its main hydrocarbon families (n-paraffins, major aromatics) over the two cells is governed by the slow preferential flow of NAPL through the porous matrix, the rapid NAPL convective flow through vertical desiccation and sub-horizontal glaciotectonic fractures, and n-paraffin biodegradation in upper layers where the rates of oxygen transfer is not limited by complexities of the pore structure. The information collected is valuable for the selection, implementation and evaluation of two in situ remediation methods.

A commercialized, continuous flow fiber optic sensor for trichloroethylene and haloforms

NASA Technical Reports Server (NTRS)

Wells, James C.; Johnson, Mark D.

1994-01-01

Purus, Inc. has commercialized a fiber optic chemical sensor using technology developed by Lawrence Livermore National Laboratory and licensed from The University of California. The basis for the sensor is the development of color within a reagent when exposed to an analyte. The sensor consists of an optrode, reagent delivery and recover system, fiber optic transmitter-receiver, controller, and display. Reagent is pumped through the optrode. Analyte diffuses across a gas permeable membrane and reacts with the reagent to form a colored product. The colored product is detected by measuring the absorbance of light from a 568 nm diode. Reagents are currently available for TCE and trihalomethanes. Initial reagent chemistry is based on the Fujiwara alkaline pyridine reaction. The optrode contacts only gas streams, but the volatility of the current analytes also allows measurements of aqueous streams, without being affected by aqueous interferents that are non-volatile. Sensitivity of the sensor has been demonstrated to 5 ppb aqueous solutions and 0.1 ppmv in flowing gas streams.

Novel combination of non-aqueous capillary electrophoresis and multivariate curve resolution-alternating least squares to determine phenolic acids in virgin olive oil.

PubMed

Godoy-Caballero, María del Pilar; Culzoni, María Julia; Galeano-Díaz, Teresa; Acedo-Valenzuela, María Isabel

2013-02-06

This paper presents the development of a non-aqueous capillary electrophoresis method coupled to UV detection combined with multivariate curve resolution-alternating least-squares (MCR-ALS) to carry out the resolution and quantitation of a mixture of six phenolic acids in virgin olive oil samples. p-Coumaric, caffeic, ferulic, 3,4-dihydroxyphenylacetic, vanillic and 4-hydroxyphenilacetic acids have been the analytes under study. All of them present different absorption spectra and overlapped time profiles with the olive oil matrix interferences and between them. The modeling strategy involves the building of a single MCR-ALS model composed of matrices augmented in the temporal mode, namely spectra remain invariant while time profiles may change from sample to sample. So MCR-ALS was used to cope with the coeluting interferences, on accounting the second order advantage inherent to this algorithm which, in addition, is able to handle data sets deviating from trilinearity, like the data herein analyzed. The method was firstly applied to resolve standard mixtures of the analytes randomly prepared in 1-propanol and, secondly, in real virgin olive oil samples, getting recovery values near to 100% in all cases. The importance and novelty of this methodology relies on the combination of non-aqueous capillary electrophoresis second-order data and MCR-ALS algorithm which allows performing the resolution of these compounds simplifying the previous sample pretreatment stages. Copyright © 2012 Elsevier B.V. All rights reserved.

In-situ Subsurface Soil Analyzer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ulmer, Chris

The Department of Energy’s (DOE’s) Terrestrial Ecosystem Science (TES) program is seeking improved sensor systems for monitoring hydro-biogeochemical processes in complex subsurface environments. The TES program is specifically interested in acquiring chemical and structural information regarding the type and nature of the hydration and redox states of subsurface chemical species. The technology should be able to perform on-site and real-time measurements to provide information not available using current sample acquisition and preservation processes. To address the needs of the DOE and the terrestrial science community, Physical Optics Corporation (POC) worked on the development of a new In-Situ Subsurface Soil Analyzermore » (ISSA) based on magnetic resonance technologies. Benchtop testing was performed to assess the feasibility of continuous wave electron pair resonance (CW-EPR) detection of chemical species in subsurface soil systems.« less

The Role of Subsurface Properties on Transport of Water and Trace Gases: 1D Simulations at Selected Mars Landing Sites.

NASA Astrophysics Data System (ADS)

Karatekin, O.; Gloesener, E.; Dehant, V. M. A.

2017-12-01

In this work, water ice stability and water vapour transport through porous martian subsurface are studied using a 1D diffusive model. The role of adsorption on water transfer in martian conditions is investigated as well as the range of parameters that have the largest effect on gas transport. In addition, adsorption kinetics is considered to examine its influence on the water vapor exchange between the subsurface and the atmosphere. As methane has been detected in the martian atmosphere, the subsurface model is then used to study methane diffusion in the CH4/CO2/H2O system from variable depths under the surface. The results of subsurface gas transport at selected locations/landing sites are shown and implications for present/future observations are discussed.

Residues of endosulfan in surface and subsurface agricultural soil and its bioremediation.

PubMed

Odukkathil, Greeshma; Vasudevan, Namasivayam

2016-01-01

The persistence of many hydrophobic pesticides has been reported by various workers in various soil environments and its bioremediation is a major concern due to less bioavailability. In the present study, the pesticide residues in the surface and subsurface soil in an area of intense agricultural activity in Pakkam Village of Thiruvallur District, Tamilnadu, India, and its bioremediation using a novel bacterial consortium was investigated. Surface (0-15 cm) and subsurface soils (15-30 cm and 30-40 cm) were sampled, and pesticides in different layers of the soil were analyzed. Alpha endosulfan and beta endosulfan concentrations ranged from 1.42 to 3.4 mg/g and 1.28-3.1 mg/g in the surface soil, 0.6-1.4 mg/g and 0.3-0.6 mg/g in the subsurface soil (15-30 cm), and 0.9-1.5 mg/g and 0.34-1.3 mg/g in the subsurface soil (30-40 cm) respectively. Residues of other persistent pesticides were also detected in minor concentrations. These soil layers were subjected to bioremediation using a novel bacterial consortium under a simulated soil profile condition in a soil reactor. The complete removal of alpha and beta endosulfan was observed over 25 days. Residues of endosulfate were also detected during bioremediation, which was subsequently degraded on the 30th day. This study revealed the existence of endosulfan in the surface and subsurface soils and also proved that the removal of such a ubiquitous pesticide in the surface and subsurface environment can be achieved in the field by bioaugumenting a biosurfactant-producing bacterial consortium that degrades pesticides. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantification of the effect of temperature gradients in soils on subsurface radon signal

NASA Astrophysics Data System (ADS)

Haquin, Gustavo; Ilzycer, Danielle; Kamai, Tamir; Zafrir, Hovav; Weisbrod, Noam

2017-04-01

Temperature gradients that develop in soils due to atmospheric temperature cycles are factors of primary importance in determining the rates and directions of subsurface gas flow. Models including mechanisms of thermal convection and thermal diffusion partially explain the impact of temperature gradients on subsurface radon transport. However, the overall impact of temperature gradients on subsurface radon transport is still not well understood. A laboratory setup was designed and built to experimentally investigate the influence of temperature gradients on radon transport under well controlled conditions. A 60 cm diameter and 120 cm tall column was thermally insulated except from the atmosphere-soil interface, such that it was constructed to simulate field conditions where temperature gradients in soils are developed following atmospheric temperature cycles. The column was filled with fine grinded phosphate rock which provided the porous media with radon source. Radon in soil-air was continuously monitored using NaI gamma detectors positioned at different heights along the column. Soil temperature, differential pressure, and relative humidity were monitored along the column. Experiments based on steep and gradual stepwise changes in ambient temperature were conducted. Absolute changes on radon levels in the order of 10-30% were measured at temperature gradients of up to ±20oC/m. Results showed a non-linear correlation between the temperature gradient and the subsurface radon concentration. An asymmetric relationship between the radon concentration and the temperature gradients for ΔT>0 and ΔT<0 was also observed. Laboratory simulations of the time- and depth-dependent temperature wave functions with frequencies ranged from a daily cycle to few days were performed. In response to the harmonic temperature behaviour radon oscillations at similar frequencies were detected correspondingly. In this work a quantitative relationship between radon and temperature gradients will be presented for cases beyond the classical conditions for thermal convection and thermal diffusion.

SUBSURFACE CHARACTERIZATION AND MONITORING TECHNIQUES: A DESK REFERENCE GUIDE - VOLUME II: THE VADOSE ZONE, FIELD SCREENING AND ANALYTICAL METHODS - APPENDICES C AND D

EPA Science Inventory

Many EPA programs, including those under the Resource Conservation and Recovery Act (RCRA) and the Comprehensive Response, Compensation, and Liability Act (CERCLA), require subsurface characterization and monitoring to detect ground-water contamination and provide data to deve...

Enhanced Remedial Amendment Delivery to Subsurface Using Shear Thinning Fluid and Aqueous Foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Lirong; Szecsody, James E.; Oostrom, Martinus

2011-04-23

A major issue with in situ subsurface remediation is the ability to achieve an even spatial distribution of remedial amendments to the contamination zones in an aquifer or vadose zone. Delivery of amendment to the aquifer using shear thinning fluid and to the vadose zone using aqueous foam has the potential to enhance the amendment distribution into desired locations and improve the remediation. 2-D saturated flow cell experiments were conducted to evaluate the enhanced sweeping, contaminant removal, and amendment persistence achieved by shear thinning fluid delivery. Bio-polymer xanthan gum solution was used as the shear thinning fluid. Unsaturated 1-D columnmore » and 2-D flow cell experiments were conducted to evaluate the mitigation of contaminant mobilization, amendment uniform distribution enhancement, and lateral delivery improvement by foam delivery. Surfactant sodium lauryl ether sulfate was used as the foaming agent. It was demonstrated that the shear thinning fluid injection enhanced the fluid sweeping over a heterogeneous system and increased the delivery of remedial amendment into low-permeability zones. The persistence of the amendment distributed into the low-perm zones by the shear thinning fluid was prolonged compared to that of amendment distributed by water injection. Foam delivery of amendment was shown to mitigate the mobilization of highly mobile contaminant from sediments under vadose zone conditions. Foam delivery also achieved more uniform amendment distribution in a heterogeneous unsaturated system, and demonstrated remarkable increasing in lateral distribution of the injected liquid compared to direct liquid injection.« less

One-carbon (bio ?) Geochemistry in Subsurface Waters of the Serpentinizing Coast Range Ophiolite

NASA Technical Reports Server (NTRS)

Hoehler, Tori M.; Mccollom, Tom; Schrenk, Matt; Cardace, Dawn

2011-01-01

Serpentinization - the aqueous alteration of ultramafic rocks - typically imparts a highly reducing and alkaline character to the reacting fluids. In turn, these can influence the speciation and potential for metabolism of one-carbon compounds in the system. We examined the aqueous geochemistry and assessed the biological potential of one-carbon compounds in the subsurface of the McLaughlin Natural Reserve (Coast Range Ophiolite, California, USA). Fluids from wells sunk at depths of 25-90 meters have pH values ranging from 9.7 to 11.5 and dissolved inorganic carbon (DIC concentrations) generally below 60 micromolar. Methane is present at concentrations up to 1.3 millimolar (approximately one-atmosphere saturation), and hydrogen concentrations are below 15 nanomolar, suggesting active consumption of H2 and production of CH4. However, methane production from CO2 is thermodynamically unfavorable under these conditions. Additionally, the speciation of DIC predominantly into carbonate at these high pH values creates a problem of carbon availability for any organisms that require CO2 (or bicarbonate) for catabolism or anabolism. A potential alternative is carbon monoxide, which is present in these waters at concentrations 2000-fold higher than equilibrium with atmospheric CO. CO is utilized in a variety of metabolisms, including methanogenesis, and bioavailability is not adversely affected by pH-dependent speciation (as for DIC). Methanogenesis from CO under in situ conditions is thermodynamically favorable and would satisfy biological energy requirements with respect to both Gibbs Energy yield and power.

Biochemical characterization of sap (latex) of a few Indian mango varieties.

PubMed

John, K Saby; Bhat, S G; Prasada Rao, U J S

2003-01-01

Mango sap (latex) from four Indian varieties was studied for its composition. Sap was separated into non-aqueous and aqueous phases. Earlier, we reported that the non-aqueous phase contained mainly mono-terpenes having raw mango aroma (Phytochemistry 52 (1999) 891). In the present study biochemical composition of the aqueous phase was studied. Aqueous phase contained little amount of protein (2.0-3.5 mg/ml) but showed high polyphenol oxidase (147-214 U/mg protein) and peroxidase (401-561 U/mg protein) activities. It contained low amounts of polyphenols and protease activities. On native PAGE, all the major protein bands exhibited both polyphenol oxidase and peroxidase activities. Both polyphenol oxidase and peroxidase activities were found to be stable in the aqueous phase of sap at 4 degrees C. Sap contained large amount of non-dialyzable and non-starchy carbohydrate (260-343 mg/ml sap) which may be responsible for maintaining a considerable pressure of fluid in the ducts. Thus, the mango sap could be a valuable by-product in the mango industry as it contains some of the valuable enzymes and aroma components.

Subsurface Microsensors for Assisted Recertification of TPS (SmarTPS)

NASA Technical Reports Server (NTRS)

Pallix, Joan B.; Milos, Frank S.; Huestis, Dave; Arnold, James O. (Technical Monitor)

1999-01-01

Commercialization of a competitive reusable launch vehicle (RLV) is a primary goal for both NASA and the U.S. aerospace industry. To expedite achievement of this goal, the Bantam-X Technology Program is funding development of innovative technologies to lower costs for access to space. Ground operations is one area where significant cost reduction is required. For the Shuttle fleet, ground operations account for over 80% of the life cycle costs, and TPS recertification accounts for 27% of the operation costs ($4.5M per flight). Bantam Task TPS-7, Subsurface Microsensors for Assisted Recertification of TPS (SmarTPS), is a joint effort between NASA centers and industry partners to develop rapid remote detection and scanning technology for inspection of TPS and detection of subsurface defects. This short paper will provide a general overview of the SmarTPS concept.

Enhancement of OCT images with vinyl polysiloxane (VPS)

NASA Astrophysics Data System (ADS)

Kang, Hobin; Darling, Cynthia L.; Fried, Daniel

2016-02-01

Several studies have shown that optical coherence tomography (OCT) can be used to measure the remaining enamel thickness and detect the location of subsurface lesions hidden under the sound enamel. Moreover studies have shown that high refractive index liquids can be used to improve the visibility of subsurface lesions in OCT images. In this study, we demonstrate that vinyl polysiloxane (VPS) impression materials which are routinely used in dentistry can be used to enhance the detection of dentinal lesions on tooth occlusal surfaces. Lesion presence was confirmed with polarized light microscopy and microradiography.

Fiber Optic Thermographic Detection of Flaws in Composites

NASA Technical Reports Server (NTRS)

Wu, Meng-Chou; Winfree, William P.

2009-01-01

Optical fibers with multiple Bragg gratings bonded to surfaces of structures were used for thermographic detection of subsurface defects in structures. The investigated structures included a 10-ply composite specimen with subsurface delaminations of various sizes and depths. Both during and following the application of a thermal heat flux to the surface, the individual Bragg grating sensors measured the temporal and spatial temperature variations. The obtained data were analyzed with thermal modeling to reveal particular characteristics of the interested areas. These results were found to be consistent with the simulation results.

System and method for investigating sub-surface features and 3D imaging of non-linear property, compressional velocity VP, shear velocity VS and velocity ratio VP/VS of a rock formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vu, Cung Khac; Skelt, Christopher; Nihei, Kurt

A system and a method for generating a three-dimensional image of a rock formation, compressional velocity VP, shear velocity VS and velocity ratio VP/VS of a rock formation are provided. A first acoustic signal includes a first plurality of pulses. A second acoustic signal from a second source includes a second plurality of pulses. A detected signal returning to the borehole includes a signal generated by a non-linear mixing process from the first and second acoustic signals in a non-linear mixing zone within an intersection volume. The received signal is processed to extract the signal over noise and/or signals resultingmore » from linear interaction and the three dimensional image of is generated.« less

Noninvasive monitoring of Pirenoxine Sodium concentration in aqueous humor based on dual-wavelength iris imaging technique

PubMed Central

Zhou, Yong; Hu, Ye; Zeng, Nan; Ji, Yanhong; Dai, Xiangsong; Li, Peng; Ma, Hui; He, Yonghong

2011-01-01

We present a noninvasive method of detecting substance concentration in the aqueous humor based on dual-wavelength iris imaging technology. Two light sources, one centered within (392 nm) and the other centered outside (850 nm) of an absorption band of Pirenoxine Sodium, a common type of drugs in eye disease treatment, were used for dual-wavelength iris imaging measurement. After passing through the aqueous humor twice, the back-scattering light was detected by a charge-coupled device (CCD). The detected images were then used to calculate the concentration of Pirenoxine Sodium. In eye model experiment, a resolution of 0.6525 ppm was achieved. Meanwhile, at least 4 ppm can be distinguished in in vivo experiment. These results demonstrated that our method can measure Pirenoxine Sodium concentration in the aqueous humor and its potential ability to monitor other materials’ concentration in the aqueous humor. PMID:21339869

Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Optimization of wetland substrates and hydraulic loading.

PubMed

Chen, Jun; Wei, Xiao-Dong; Liu, You-Sheng; Ying, Guang-Guo; Liu, Shuang-Shuang; He, Liang-Ying; Su, Hao-Chang; Hu, Li-Xin; Chen, Fan-Rong; Yang, Yong-Qiang

2016-09-15

This study aimed to assess removal potential of antibiotics and antibiotic resistance genes (ARGs) in raw domestic wastewater by various mesocosm-scale horizontal subsurface-flow constructed wetlands (CWs) planted Cyperus alternifolius L. with different design parameters. Twelve CWs with three hydraulic loading rates (HLR 10, 20 and 30cm/day) and four substrates (oyster shell, zeolite, medical stone and ceramic) were set up in order to select the best optimized wetland. The result showed that 7 target antibiotics compounds including erythromycin-H2O, lincomycin, monensin, ofloxacin, sulfamerazine, sulfamethazine and novobiocin were detected, and all selected 18 genes (three sulfonamide resistance genes (sul1, sul2 and sul3), four tetracycline resistance genes (tetG, tetM, tetO and tetX), two macrolide resistance genes (ermB and ermC), three quinolone resistance genes (qnrB, qnrD and qnrS) and four chloramphenicol resistance genes (cmlA, fexA, fexB and floR)) and two integrase genes (int1 and int2) were positively detected in the domestic wastewaters. The aqueous removal rates of the total antibiotics ranged from17.9 to 98.5%, while those for the total ARGs varied between 50.0 and 85.8% by the mesocosm-scale CWs. After considering their aqueous removal rates in combination with their mass removals, the CW with zeolite as the substrate and HLR of 20cm/day was selected as the best choice. Combined chemical and biological analyses indicate that both microbial degradation and physical sorption processes were responsible for the fate of antibiotics and ARGs in the wetlands. The findings from this study suggest constructed wetlands could be a promising technology for the removal of emerging contaminants such as antibiotics and ARGs in domestic wastewater. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficient ensemble system based on the copper binding motif for highly sensitive and selective detection of cyanide ions in 100% aqueous solutions by fluorescent and colorimetric changes.

PubMed

Jung, Kwan Ho; Lee, Keun-Hyeung

2015-09-15

A peptide-based ensemble for the detection of cyanide ions in 100% aqueous solutions was designed on the basis of the copper binding motif. 7-Nitro-2,1,3-benzoxadiazole-labeled tripeptide (NBD-SSH, NBD-SerSerHis) formed the ensemble with Cu(2+), leading to a change in the color of the solution from yellow to orange and a complete decrease of fluorescence emission. The ensemble (NBD-SSH-Cu(2+)) sensitively and selectively detected a low concentration of cyanide ions in 100% aqueous solutions by a colorimetric change as well as a fluorescent change. The addition of cyanide ions instantly removed Cu(2+) from the ensemble (NBD-SSH-Cu(2+)) in 100% aqueous solutions, resulting in a color change of the solution from orange to yellow and a "turn-on" fluorescent response. The detection limits for cyanide ions were lower than the maximum allowable level of cyanide ions in drinking water set by the World Health Organization. The peptide-based ensemble system is expected to be a potential and practical way for the detection of submicromolar concentrations of cyanide ions in 100% aqueous solutions.

Effects of 6 months of aging in water on hardness and surface roughness of two microhybrid dental composites.

PubMed

de Moraes, Rafael Ratto; Marimon, José Laurindo Machado; Schneider, Luis Felipe; Sinhoreti, Mário Alexandre Coelho; Correr-Sobrinho, Lourenço; Bueno, Márcia

2008-06-01

This study assessed the effect of 6 months of aging in water on surface roughness and surface/subsurface hardness of two microhybrid resin composites. Filtek Z250 and Charisma were tested. Cylindrical specimens were obtained and stored in distilled water for 24 hours or 6 months, at 37 degrees C. For Knoop hardness evaluation, the specimens were transversely wet-flattened, and indentations were made on surface and subsurface layers. Data were submitted to three-way ANOVA and Tukey's test (alpha < or = 0.05). Surface roughness baseline measurements were made at 24 hours and repeated after 6 months of storage. Data were submitted to repeated measures ANOVA and Tukey's test (alpha < or = 0.05). Surface hardness (KHN, kg/mm(2)) means (+/- standard deviation) ranged from 55 +/- 1 to 49 +/- 4 for Z250 and from 50 +/- 2 to 41 +/- 3 for Charisma, at 24 hours and 6 months, respectively. Subsurface means ranged from 58 +/- 2 to 61 +/- 3 for Z250 and from 50 +/- 1 to 54 +/- 2 for Charisma, at 24 hours and 6 months. For both composites, the aged specimens presented significantly softer surfaces (p < 0.01). For the subsurface hardness, alteration after storage was detected only for Charisma, which presented a significant rise in hardness (p < 0.01). Z250 presented significantly harder surface and subsurface layers in comparison with Charisma. Surface roughness (Ra, mum) means ranged from 0.07 +/- 0.00 to 0.07 +/- 0.01 for Z250 and from 0.06 +/- 0.01 to 0.07 +/- 0.01 for Charisma, at 24 hours and 6 months, respectively. For both composites, no significant roughness alteration was detected during the study (p= 0.386). The 6-month period of storage in water presented a significant softening effect on the surfaces of the composites, although no significant deleterious alteration was detected for the subsurface hardness. In addition, the storage period had no significant effect on the surface roughness of the materials.

Advancing Knowledge on Fugitive Natural Gas from Energy Resource Development at a Controlled Release Field Observatory

NASA Astrophysics Data System (ADS)

Cahill, A. G.; Chao, J.; Forde, O.; Prystupa, E.; Mayer, K. U.; Black, T. A.; Tannant, D. D.; Crowe, S.; Hallam, S.; Mayer, B.; Lauer, R. M.; van Geloven, C.; Welch, L. A.; Salas, C.; Levson, V.; Risk, D. A.; Beckie, R. D.

2017-12-01

Fugitive gas, comprised primarily of methane, can be unintentionally released from upstream oil and gas development either at surface from leaky infrastructure or in the subsurface through failure of energy well bore integrity. For the latter, defective cement seals around energy well casings may permit buoyant flow of natural gas from the deeper subsurface towards shallow aquifers, the ground surface and potentially into the atmosphere. Concerns associated with fugitive gas release at surface and in the subsurface include contributions to greenhouse gas emissions, subsurface migration leading to accumulation in nearby infrastructure and impacts to groundwater quality. Current knowledge of the extent of fugitive gas leakage including how to best detect and monitor over time, and particularly its migration and fate in the subsurface, is incomplete. We have established an experimental field observatory for evaluating fugitive gas leakage in an area of historic and ongoing hydrocarbon resource development within the Montney Resource Play of the Western Canadian Sedimentary Basin, British Columbia, Canada. Natural gas will be intentionally released at surface and up to 25 m below surface at various rates and durations. Resulting migration patterns and impacts will be evaluated through examination of the geology, hydrogeology, hydro-geochemistry, isotope geochemistry, hydro-geophysics, vadose zone and soil gas processes, microbiology, and atmospheric conditions. The use of unmanned aerial vehicles and remote sensors for monitoring and detection of methane will also be assessed for suitability as environmental monitoring tools. Here we outline the experimental design and describe initial research conducted to develop a detailed site conceptual model of the field observatory. Subsequently, results attained from pilot surface and sub-surface controlled natural gas releases conducted in late summer 2017 will be presented as well as results of numerical modelling conducted to plan methane release experiments in 2018 and onwards. This research will create knowledge which informs strategies to detect and monitor fugitive gas fluxes at the surface and in groundwater; as well as guide associated regulatory and technical policies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jun, Young -Shin; Kim, Doyoon; Neil, Chelsea W.

Here, mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth’s crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolutionmore » of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.« less

Heterogeneous nucleation and growth of nanoparticles at environmental interfaces

DOE PAGES

Jun, Young -Shin; Kim, Doyoon; Neil, Chelsea W.

2016-08-11

Here, mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth’s crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolutionmore » of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.« less

Heterogeneous Nucleation and Growth of Nanoparticles at Environmental Interfaces.

PubMed

Jun, Young-Shin; Kim, Doyoon; Neil, Chelsea W

2016-09-20

Mineral nucleation is a phase transformation of aqueous components to solids with an accompanying creation of new surfaces. In this evolutional, yet elusive, process, nuclei often form at environmental interfaces, which provide remarkably reactive sites for heterogeneous nucleation and growth. Naturally occurring nucleation processes significantly contribute to the biogeochemical cycles of important components in the Earth's crust, such as iron and manganese oxide minerals and calcium carbonate. However, in recent decades, these cycles have been significantly altered by anthropogenic activities, which affect the aqueous chemistry and equilibrium of both surface and subsurface systems. These alterations can trigger the dissolution of existing minerals and formation of new nanoparticles (i.e., nucleation and growth) and consequently change the porosity and permeability of geomedia in subsurface environments. Newly formed nanoparticles can also actively interact with components in natural and engineered aquatic systems, including those posing a significant hazard such as arsenic. These interactions can bilaterally influence the fate and transport of both newly formed nanoparticles and aqueous components. Due to their importance in natural and engineered processes, heterogeneous nucleation at environmental interfaces has started to receive more attention. However, a lack of time-resolved in situ analyses makes the evaluation of heterogeneous nucleation challenging because the physicochemical properties of both the nuclei and surfaces significantly and dynamically change with time and aqueous chemistry. This Account reviews our in situ kinetic studies of the heterogeneous nucleation and growth behaviors of iron(III) (hydr)oxide, calcium carbonate, and manganese (hydr)oxide minerals in aqueous systems. In particular, we utilized simultaneous small-angle and grazing incidence small-angle X-ray scattering (SAXS/GISAXS) to investigate in situ and in real-time the effects of water chemistry and substrate identity on heterogeneously and homogeneously formed nanoscale precipitate size dimensions and total particle volume. Using this technique, we also provided a new platform for quantitatively comparing between heterogeneous and homogeneous nucleation and growth of nanoparticles and obtaining undiscovered interfacial energies between nuclei and surfaces. In addition, nanoscale surface characterization tools, such as in situ atomic force microscopy (AFM), were utilized to support and complement our findings. With these powerful nanoscale tools, we systematically evaluated the influences of environmentally abundant (oxy)anions and cations and the properties of environmental surfaces, such as surface charge and hydrophobicity. The findings, significantly enhanced by in situ observations, can lead to a more accurate prediction of the behaviors of nanoparticles in the environment and enable better control of the physicochemical properties of nanoparticles in engineered systems, such as catalytic reactions and energy storage.

A new visible-light-excitable ICT-CHEF-mediated fluorescence 'turn-on' probe for the selective detection of Cd(2+) in a mixed aqueous system with live-cell imaging.

PubMed

Goswami, Shyamaprosad; Aich, Krishnendu; Das, Sangita; Das Mukhopadhyay, Chitrangada; Sarkar, Deblina; Mondal, Tapan Kumar

2015-03-28

A new quinoline based sensor was developed and applied for the selective detection of Cd(2+) both in vitro and in vivo. The designed probe displays a straightforward approach for the selective detection of Cd(2+) with a prominent fluorescence enhancement along with a large red shift (∼38 nm), which may be because of the CHEF (chelation-enhanced fluorescence) and ICT (internal charge transfer) processes after interaction with Cd(2+). The interference from other biologically important competing metal ions, particularly Zn(2+), has not been observed. The visible-light excitability of the probe merits in the viewpoint of its biological application. The probe enables the detection of intracellular Cd(2+) with non-cytotoxic effects, which was demonstrated with the live RAW cells. The experimentally observed change in the structure and electronic properties of the sensor after the addition of Cd(2+) were modelled by the density functional theory (DFT) and time-dependent density functional theory (TDDFT) computational calculations, respectively. Moreover, the test strip experiment with this sensor exhibits both absorption and fluorescence color changes when exposed to Cd(2+) in a mixed aqueous solution, which also makes the probe more useful. The minimum limit of detection of Cd(2+) by the probe was in the range of 9.9 × 10(-8) M level.

Mineralogy of Surface Serpentinite Outcrops in the Coast Range Ophiolite: Implications for the Deep Biosphere and Astrobiology

NASA Astrophysics Data System (ADS)

Mccann, A. R.; Cardace, D.; Carnevale, D.; Ehlmann, B. L.

2011-12-01

California contains a number of ultramafic (Fe- and Mg rich) rock bodies, including the Coast Range Ophiolite, a block of oceanic crust and upper mantle tectonically emplaced onto land. These ultramafic rocks are primarily composed of olivine and pyroxene, both of which are stable at the high temperatures and pressures in the deep subsurface where they crystallize but become unstable at low temperature and low pressure conditions near the surface. They are highly reduced rocks, creating chemical disequilibria, which can theoretically provide energy to chemoautotrophic organisms. Serpentinization (serpentine-forming) reactions between the rocks and water produce hydrogen molecules, which can be metabolized by diverse organisms. Earth and Mars have shown evidence of similar early geologic histories, possibly with widespread reducing habitable environments (Schulte et al., 2006). Recent data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) have shown serpentine-bearing outcrops near Nili Fossae (21 N, 282 W) and elsewhere in Mars' cratered highlands. Serpentine-bearing outcrops are rare, but their presence confirms that such systems involving the aqueous alteration of ultramafic rocks were active in the past (specifically during the Noachian epoch (older than ~3.7 billion years), possibly producing aqueous habitats suitable for chemoautotrophic life (Ehlmann et al., 2010). Remotely sensed data cannot confirm whether there is active serpentinization on Mars, however exposed, presently serpentinizing ultramafics in terrestrial ophiolites such as those of the California Coast Range provide points of comparison for similar Martian rocks. Volume expansion during serpentinization fractures the host rock, exposing new reaction surfaces, allowing further serpentinization. If subsurface liquid water is present on Mars, serpentinization may still be occurring. We will provide x-ray diffraction and petrographic data for surface serpentinites from the Coast Range Ophiolite, along with aerial-view maps, which will be compared with imagery and data for recently confirmed serpentinite exposures in the Nili Fossae region of the Martian surface. A summary table of terrestrial microbes (and their metabolisms) detected in serpentinite groundwaters will be provided, to add specificity to candidate subterranean life forms on Mars, be they active presently or in the planet's history. Ehlmann et al. 2010. GRL 37:1-5 Schulte et al. 2006. Astrobiology 6(2):364-376

The Possibility of Serpentinization on Enceladus

NASA Astrophysics Data System (ADS)

Boye Nissen, Silas; Taubner, Ruth-Sophie; Leitner, Johannes J.; Firneis, Maria G.

2015-04-01

Enceladus, an icy moon of Saturn, is considered a potential place for a second genesis of life in a rather easy accessible environment for future space missions. Plumes erupting material out to Saturn's E-ring have been detected. This and the latest gravity data received by NASA's Cassini probe highly suggest a regional subsurface water reservoir to exist. The Cassini mission has detected all the necessary elements for life in these plumes and few ecosystems known from the Earth could in theory exist on this moon. These ecosystems rely on a sufficient hydrogen source. On Earth, this molecule is known to be produced when the oceans interact with silicates in the mantle through a geochemical process called serpentinization. The aim of this work is first of all to determine whether serpentinization is possible on Enceladus at an assumed pressure range of 25-50 bars and a temperature range of 0-50 °C. If it is possible, then the second aim is to estimate the hydrogen production rate. Therefore, geochemical modeling with the EQ3/6 software package has been applied and thermody-namic databases have been created with the use of the DBCreate program. Due to the present lack of data on the chemical composition of the subsurface sea it is assumed to be equal to the chemical composition of the plumes. Finally, the importance of the pH value (7-9) is studied. Models based on Enceladus being a captured comet or aggregated ring material are used to specify the core composition. These are different combinations of pyroxenes and olivines or no silicates, respectively. The results show that serpentinization is ongoing in all models with silicates at these low pressure and temperature ranges. Hydrogen is only produced in the presence of an iron-rich end-member of either pyroxene (ferrosilite) or olivine (fayalite). In these cases, the dihydrogen concentration is estimated to be around 2.0 mg/kg solution. Changing the pH value did not make any differences to the results. It is discussed how the complex aqueous solution assumed (based on the composition of the plumes) affect the serpentinization process on Enceladus. In addition, it is discussed if the pressure and temperature ranges are too small to make a significant change on the dihydrogen concentration. This work shows that serpentinization seems to be possible at the low pressure and temperature values found at the water/rock boundary on Enceladus. To improve the estimate of the hydrogen production rate, measurements for the silicate ions in the aqueous solution on Enceladus are needed. We would like to thank Wolfgang Bach from the Research Group "Petrology of the Ocean Crust" (University of Bremen) for his very helpful support on applying the geochemical modeling software.

Comparison of point-source pollutant loadings to soil and groundwater for 72 chemical substances.

PubMed

Yu, Soonyoung; Hwang, Sang-Il; Yun, Seong-Taek; Chae, Gitak; Lee, Dongsu; Kim, Ki-Eun

2017-11-01

Fate and transport of 72 chemicals in soil and groundwater were assessed by using a multiphase compositional model (CompFlow Bio) because some of the chemicals are non-aqueous phase liquids or solids in the original form. One metric ton of chemicals were assumed to leak in a stylized facility. Scenarios of both surface spills and subsurface leaks were considered. Simulation results showed that the fate and transport of chemicals above the water table affected the fate and transport of chemicals below the water table, and vice versa. Surface spill scenarios caused much less concentrations than subsurface leak scenarios because leaching amounts into the subsurface environment were small (at most 6% of the 1 t spill for methylamine). Then, simulation results were applied to assess point-source pollutant loadings to soil and groundwater above and below the water table, respectively, by multiplying concentrations, impact areas, and durations. These three components correspond to the intensity of contamination, mobility, and persistency in the assessment of pollutant loading, respectively. Assessment results showed that the pollutant loadings in soil and groundwater were linearly related (r 2  = 0.64). The pollutant loadings were negatively related with zero-order and first-order decay rates in both soil (r = - 0.5 and - 0.6, respectively) and groundwater (- 1.0 and - 0.8, respectively). In addition, this study scientifically defended that the soil partitioning coefficient (K d ) significantly affected the pollutant loadings in soil (r = 0.6) and the maximum masses in groundwater (r = - 0.9). However, K d was not a representative factor for chemical transportability unlike the expectation in chemical ranking systems of soil and groundwater pollutants. The pollutant loadings estimated using a physics-based hydrogeological model provided a more rational ranking for exposure assessment, compared to the summation of persistency and transportability scores in the chemical ranking systems. In the surface spill scenario, the pollutant loadings were zeros for all chemicals, except methylamine to soil whose pollutant loading was smaller than that in the subsurface leak scenario by 4 orders of magnitude. The maximum mass and the average mass multiplied by duration in soil greatly depended on leaching fluxes (r = 1.0 and 0.9, respectively), while the effect of leaching fluxes diminished below the water table. The contribution of this work is that a physics-based numerical model was used to quantitatively compare the subsurface pollutant loading in a chemical accident for 72 chemical substances, which can scientifically defend a simpler and more qualitative assessment of pollutant loadings. Besides, this study assessed pollutant loadings to soil (unsaturated zone) and groundwater (saturated zone) all together and discussed their interactions.

Modeling Sorption and Degradation of 17β-Estradiol-17-Sulfate in Agricultural Soils

NASA Astrophysics Data System (ADS)

Bai, X.; Casey, F. X.; Hakk, H.; Shrestha, S. L.; DeSutter, T.; Khan, E.; Oduor, P. G.

2011-12-01

The natural steroid hormone, 17β-estradiol (E2), can be an endocrine disruptor at part-per trillion levels. Laboratory studies indicate a low potential for E2 persistence and mobility in the environment; however, field studies consistently indicate the presence of E2 and its primary metabolite, estrone, at levels sufficiently high to impact water quality. To facilitate urine excretion, animals may release E2 as a sulfated conjugate, which would have a higher aqueous solubility than the parent compound. We hypothesize that E2 conjugates contribute to the detection of free estrogens in the environment. The objective of this study was to determine the sorption, degradation, and mobility of a model conjugate, 17β-estradiol-17-sulfate (E2-17S), in agricultural soils. Radiolabeled E2-17S ([14C]E2-17S) was chemically synthesized in a three-step process, and then batch experiments were conducted in natural and sterile soils. Additionally, soil organic carbon (OC) was varied (1.29 and 0.26%) to investigate its effect on the fate of [14C]E2-17S. Liquid scintillation counting (LSC) was used in concert with high performance liquid chromatography (HPLC) to detect and quantitate parent compound and metabolites of E2-17S in the aqueous and bound phases. Residual soil was combusted to determine non-extractable levels of 14C. The E2-17S was relatively stable in the aqueous phase for natural and sterile soils. Mono- and di- hydroxyl E2-17S were detected as metabolites of E2-17S in the aqueous phase above both sterile and natural soil. Deconjugation to form E2 was not observed in aqueous phase; however, E2 and estrone were extracted from both natural and sterile soils. A conceptual model was developed to simulate and identify the fate and transport processes of E2-17S. Organic carbon was found to be an important factor affecting the sorption and degradation of E2-17S in soils.

Influence of water chemistry and travel distance on bacteriophage PRD-1 transport in a sandy aquifer

USGS Publications Warehouse

Blanford, W.J.; Brusseau, M.L.; Jim Yeh, T.-C.; Gerba, C.P.; Harvey, R.

2005-01-01

Experiments were conducted to evaluate the impact of groundwater chemistry and travel distance on the transport and fate behavior of PRD-1, a bacteriophage employed as a surrogate tracer for pathogenic enteric viruses. The experiments were conducted in the unconfined aquifer at the United States Geological Survey Cape Cod Toxic-Substances Hydrology Research Site in Falmouth, Massachusetts. The transport behavior of bromide (Br-) and PRD-1 were evaluated in a sewage-effluent contaminated zone and a shallower uncontaminated zone at this site. Several multilevel sampling devices located along a 13-m transect were used to collect vertically discrete samples to examine longitudinal and vertical variability of PRD-1 retardation and attenuation. The concentration of viable bacteriophage in the aqueous phase decreased greatly during the first few meters of transport. This decrease is attributed to a combination of colloid filtration (attachment) and inactivation. The removal was greater (10 -12 relative recovery) and occurred within the first meter for the uncontaminated zone, whereas it was lesser (10-9 relative recovery) and occurred over 4 m in the contaminated zone. The lesser removal observed for the contaminated zone is attributed to the influence of sorbed and dissolved organic matter, phosphate, and other anions, which are present in higher concentrations in the contaminated zone, on PRD-1 attachment. After the initial decrease, the aqueous PRD-1 concentrations remained essentially constant in both zones for the remainder of the tests (total travel distances of 13 m), irrespective of variations in geochemical properties within and between the two zones. The viable, mobile PRD-1 particles traveled at nearly the rate of bromide, which was used as a non-reactive tracer. The results of this study indicate that a small fraction of viable virus particles may persist in the aqueous phase and travel significant distances in the subsurface environment. ?? 2005 Elsevier Ltd. All rights reserved.

Emulsification kinetics during quasi-miscible flow in dead-end pores

NASA Astrophysics Data System (ADS)

Broens, M.; Unsal, E.

2018-03-01

Microemulsions have found applications as carriers for the transport of solutes through various porous media. They are commonly pre-prepared in bulk form, and then injected into the medium. The preparation is done by actively mixing the surfactant, water and oil, and then allowing the mixture to stagnate until equilibrium is reached. The resulting microemulsion characteristics of the surfactant/oil/water system are studied at equilibrium conditions, and perfect mixing is assumed. But in applications like subsurface remediation and enhanced oil recovery, microemulsion formation may occur in the pore space. Surfactant solutions are injected into the ground to solubilize and/or mobilize the non-aqueous phase liquids (NAPLs) by in-situ emulsification. Flow dynamics and emulsification kinetics are coupled, which also contributes to in-situ mixing. In this study, we investigated the nature of such coupling for a quasi-miscible fluid system in a conductive channel with dead-end extensions. A microfluidic setup was used, where an aqueous solution of an anionic, internal olefin sulfonate 20-24 (IOS) surfactant was injected into n-decane saturated glass micromodel. The oil phase was coloured using a solvatochromatic dye allowing for direct visualization of the aqueous and oil phases as well as their microemulsions under fluorescent light. Presence of both conductive and stagnant dead-end channels in a single pore system made it possible to isolate different transport mechanisms from each other but also allowed to study the transitions from one to the other. In the conductive channel, the surfactant was carried with flow, and emulsification was controlled by the localized flow dynamics. In the stagnant zones, the driving force of the mass transfer was driven by the chemical concentration gradient. Some of the equilibrium phase behaviour characteristics of the surfactant/oil/water system were recognisable during the quasi-miscible displacement. However, the equilibrium tests alone were not sufficient to predict the emulsification process under dynamic conditions.

Recovery of community genomes to assess subsurface metabolic potential: exploiting the capacity of next generation sequencing-based metagenomics

NASA Astrophysics Data System (ADS)

Wrighton, K. C.; Thomas, B.; Miller, C. S.; Sharon, I.; Wilkins, M. J.; VerBerkmoes, N. C.; Handley, K. M.; Lipton, M. S.; Hettich, R. L.; Williams, K. H.; Long, P. E.; Banfield, J. F.

2011-12-01

With the goal of developing a deterministic understanding of the microbiological and geochemical processes controlling subsurface environments, groundwater bacterial communities were collected from the Rifle Integrated Field Research Challenge (IFRC) site. Biomass from three temporal acetate-stimulated groundwater samples were collected during a period of dominant Fe(III)-reduction, in a region of the aquifer that had previously received acetate amendment the year prior. Phylogenetic analysis revealed a diverse Bacterial community, notably devoid of Archaea with 249 taxa from 9 Bacterial phyla including the dominance of uncultured candidate divisions, BD1-5, OD1, and OP11. We have reconstructed 86 partial to near-complete genomes and have performed a detailed characterization of the underlying metabolic potential of the ecosystem. We assessed the natural variation and redundancy in multi-heme c-type cytochromes, sulfite reductases, and central carbon metabolic pathways. Deep genomic sampling indicated the community contained various metabolic pathways: sulfur oxidation coupled to microaerophilic conditions, nitrate reduction with both acetate and inorganic compounds as donors, carbon and nitrogen fixation, antibiotic warfare, and heavy-metal detoxification. Proteomic investigations using predicted proteins from metagenomics corroborated that acetate oxidation is coupled to reduction of oxygen, sulfur, nitrogen, and iron across the samples. Of particular interest was the detection of acetate oxidizing and sulfate reducing proteins from a Desulfotalea-like bacterium in all three time points, suggesting that aqueous sulfide produced by active sulfate-reducing bacteria could contribute to abiotic iron reduction during the dominant iron reduction phase. Additionally, proteogenomic analysis verified that a large portion of the community, including members of the uncultivated BD1-5, are obligate fermenters, characterized by the presence of hydrogen-evolving hydrogenases, the capacity to oxidize complex organic carbon, as well as lack of membrane bound electron transport chains and an incomplete citric acid cycle. We propose that these organisms grow cryptically on residual biomass from previous biostimulation experiments and thus demonstrate that resource utilization and turnover in the aquifer can be decoupled from existing acetate amendment and external terminal electron accepting processes. In addition to the first recovery of multiple genomes from these novel candidate divisions, our community genomic approach uncovered viral diversity not yet observed at the site, with the reconstruction of six phage genomes and the presence of CRISPR loci detected in bacterial genomes from diverse lineages. These findings have implications for predictive ecosystem modeling, highlighting the importance of integrating the response, adaptation, as well as biological and geochemical feedback mechanisms existing within complex subsurface communities to long term organic carbon amendment.

Infrared Spectroscopic Analyses of Sulfate, Nitrate, and Carbonate-bearing Atacama Desert Soils: Analogs for the Interpretation of Infrared Spectra from the Martian Surface

NASA Technical Reports Server (NTRS)

Dalton, J. B.; Dalton, J. B.; Ewing, S. A.; Amundson, R.; McKay, C. P.

2005-01-01

The Atacama Desert of northern Chile is the driest desert on Earth, receiving only a few mm of rain per decade. The Mars climate may, in the past, have been punctuated by short-lived episodes of aqueous activity. The paleo-Martian environment may have had aqueous conditions similar to the current conditions that exist in the Atacama, and Mars soils may have formed with soil chemistry and mineralogy similar to those found in the Atacama. Remote and in-situ analysis of the Martian surface using infrared technology has a long heritage. Future investigations of the subsurface mineralogy are likely to build upon this heritage, and will benefit from real life lessons to be learned from terrestrial analog studies. To that end, preliminary results from a near- and mid-infrared spectroscopic study of Atacama soil profiled at a range of depths are presented.

Variations in Gas and Water Pulses at an Arctic Seep: Fluid Sources and Methane Transport

NASA Astrophysics Data System (ADS)

Hong, W.-L.; Torres, M. E.; Portnov, A.; Waage, M.; Haley, B.; Lepland, A.

2018-05-01

Methane fluxes into the oceans are largely dependent on the methane phase as it migrates upward through the sediments. Here we document decoupled methane transport by gaseous and aqueous phases in Storfjordrenna (offshore Svalbard) and propose a three-stage evolution model for active seepage in the region where gas hydrates are present in the shallow subsurface. In a preactive seepage stage, solute diffusion is the primary transport mechanism for methane in the dissolved phase. Fluids containing dissolved methane have high 87Sr/86Sr ratios due to silicate weathering in the microbial methanogenesis zone. During the active seepage stage, migration of gaseous methane results in near-seafloor gas hydrate formation and vigorous seafloor gas discharge with a thermogenic fingerprint. In the postactive seepage stage, the high concentration of dissolved lithium points to the contribution of a deeper-sourced aqueous fluid, which we postulate advects upward following cessation of gas discharge.

Efficacy of acetate-amended biostimulation for uranium sequestration: Combined analysis of sediment/groundwater geochemistry and bacterial community structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jie; Veeramani, Harish; Qafoku, Nikolla P.

Systematic flow-through column experiments were conducted using sediments and ground water collected from different subsurface localities at the U.S. Department of Energy's Integrated Field Research Challenge site in Rifle, Colorado. The principal purpose of this study is to gain a better understanding of the interactive effects of groundwater geochemistry, sediment mineralogy, and indigenous bacterial community structures on the efficacy of uranium removal from the groundwater with/without acetate amendment. Overall, we find that the subtle variations in the sediments' mineralogy, particle size, redox conditions, as well as contents of metal(loid) co-contaminants showed a pronounced effect on the associated bacterial population andmore » composition, which mainly determines the system's performance with respect to uranium removal. Positive relationship was identified between the abundance of dissimilatory sulfate-reduction genes (i.e., drsA), markers of sulfatereducing bacteria, and the sediments' propensity to sequester aqueous uranium. In contrast, no obvious connections were observed between the abundance of common iron-reducing bacteria, e.g., Geobacter spp., and the sediments' ability to sequester uranium. In the sediments with low bacterial biomass and the absence of sulfate-reducing conditions, abiotic adsorption onto mineral surfaces such as phyllosilicates likely played a relatively major role in the attenuation of aqueous uranium; however, in these scenarios, acetate amendment induced detectable rebounds in the effluent uranium concentrations. The results of this study suggest that reductive immobilization of uranium can be achieved under predominantly sulfate-reducing conditions, and provide insight into the integrated roles of various biogeochemical components in long-term uranium sequestration.« less

Efficacy of acetate-amended biostimulation for uranium sequestration: Combined analysis of sediment/groundwater geochemistry and bacterial community structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jie; Veeramani, Harish; Qafoku, Nikolla P.

Systematic flow-through column experiments were conducted using sediments and ground water collected from different subsurface localities at the U.S. Department of Energy's Integrated Field Research Challenge site in Rifle, Colorado. The principal purpose of this study is to gain a better understanding of the interactive effects of groundwater geochemistry, sediment mineralogy, and indigenous bacterial community structures on the efficacy of uranium removal from the groundwater with/without acetate amendment. Overall, we find that the subtle variations in the sediments' mineralogy, redox conditions, as well as contents of metal(loid) co-contaminants showed a pronounced effect on the associated bacterial population and composition, whichmore » mainly determines the system's performance with respect to uranium removal. Positive relationship was identified between the abundance of dissimilatory sulfate-reduction genes (i.e., drsA), markers of sulfate-reducing bacteria, and the sediments' propensity to sequester aqueous uranium. In contrast, no obvious connections were observed between the abundance of common iron-reducing bacteria, e.g., Geobacter spp., and the sediments' ability to sequester uranium. In the sediments with low bacterial biomass and the absence of sulfate-reducing conditions, abiotic adsorption onto mineral surfaces such as phyllosilicates likely played a relatively major role in the attenuation of aqueous uranium; however, in these scenarios, acetate amendment induced detectable rebounds in the effluent uranium concentrations. Lastly, the results of this study suggest that immobilization of uranium can be achieved under predominantly sulfate-reducing conditions, and provide insight into the integrated roles of various biogeochemical components in long-term uranium sequestration.« less

Efficacy of acetate-amended biostimulation for uranium sequestration: Combined analysis of sediment/groundwater geochemistry and bacterial community structure

DOE PAGES

Xu, Jie; Veeramani, Harish; Qafoku, Nikolla P.; ...

2016-12-29

Systematic flow-through column experiments were conducted using sediments and ground water collected from different subsurface localities at the U.S. Department of Energy's Integrated Field Research Challenge site in Rifle, Colorado. The principal purpose of this study is to gain a better understanding of the interactive effects of groundwater geochemistry, sediment mineralogy, and indigenous bacterial community structures on the efficacy of uranium removal from the groundwater with/without acetate amendment. Overall, we find that the subtle variations in the sediments' mineralogy, redox conditions, as well as contents of metal(loid) co-contaminants showed a pronounced effect on the associated bacterial population and composition, whichmore » mainly determines the system's performance with respect to uranium removal. Positive relationship was identified between the abundance of dissimilatory sulfate-reduction genes (i.e., drsA), markers of sulfate-reducing bacteria, and the sediments' propensity to sequester aqueous uranium. In contrast, no obvious connections were observed between the abundance of common iron-reducing bacteria, e.g., Geobacter spp., and the sediments' ability to sequester uranium. In the sediments with low bacterial biomass and the absence of sulfate-reducing conditions, abiotic adsorption onto mineral surfaces such as phyllosilicates likely played a relatively major role in the attenuation of aqueous uranium; however, in these scenarios, acetate amendment induced detectable rebounds in the effluent uranium concentrations. Lastly, the results of this study suggest that immobilization of uranium can be achieved under predominantly sulfate-reducing conditions, and provide insight into the integrated roles of various biogeochemical components in long-term uranium sequestration.« less

Filling the gap: using non-invasive geophysical methods to monitor the processes leading to enhanced carbon turnover induced by periodic water table fluctuations

NASA Astrophysics Data System (ADS)

Mellage, A.; Pronk, G.; Atekwana, E. A.; Furman, A.; Rezanezhad, F.; Van Cappellen, P.

2017-12-01

Subsurface transition environments such as the capillary fringe are characterized by steep gradients in redox conditions. Spatial and temporal variations in electron acceptor and donor availability - driven by hydrological changes - may enhance carbon turnover, in some cases resulting in pulses of CO2-respiration. Filling the mechanistic knowledge gap between the hydrological driver and its biogeochemical effects hinges on our ability to monitor microbial activity and key geochemical markers at a high spatial and temporal resolution. However, direct access to subsurface biogeochemical processes is logistically difficult, invasive and usually expensive. In-line, non-invasive geophysical techniques - Spectral Induced Polarization (SIP) and Electrodic Potential (EP), specifically - offer a comparatively inexpensive alternative and can provide data with high spatial and temporal resolution. The challenge lies in linking electrical responses to specific changes in biogeochemical processes. We conducted SIP and EP measurements on a soil column experiment where an artificial soil mixture was subjected to monthly drainage and imbibition cycles. SIP responses showed a clear dependence on redox zonation and microbial abundance. Temporally variable responses exhibited no direct moisture dependence suggesting that the measured responses recorded changes in microbial activity and coincided with the depth interval over which enhanced carbon turnover was observed. EP measurements detected the onset of sulfate mineralization and mapped its depth zonation. SIP and EP signals thus detected enhanced microbial activity within the water table fluctuation zone as well as the timing of the development of specific reactive processes. These findings can be used to relate measured electrical signals to specific reaction pathways and help inform reactive transport models, increasing their predictive capabilities.

Methods of Oil Detection in Response to the Deepwater ...

EPA Pesticide Factsheets

Detecting oil in the northern Gulf of Mexico following the Deepwater Horizon oil spill presented unique challenges due to the spatial and temporal extent of the spill and the subsequent dilution of oil in the environment. Over time, physical, chemical, and biological processes altered the composition of the oil, further complicating its detection. Reservoir fluid, containing gas and oil, released from the Macondo well was detected in surface and subsurface environments. Oil monitoring during and after the spill required a variety of technologies, including nimble adaptation of techniques developed for non-oil-related applications. The oil detection technologies employed varied in sensitivity, selectivity, strategy, cost, usability, expertise of user, and reliability. Innovative technologies ranging from remote sensing to laboratory analytical techniques were employed and produced new information relevant to oil spill detection, including the chemical characterization, the dispersion effectiveness, and the detection limits of oil. The challenge remains to transfer these new technologies to oil spill responders so that detection of oil following a spill can be improved. To publish a perspective paper on oil detection technologies during the Deepwater Horizon Oil Spill. This is for a special issue book/journal.

Probability of detection of internal voids in structural ceramics using microfocus radiography

NASA Technical Reports Server (NTRS)

Baaklini, G. Y.; Roth, D. J.

1986-01-01

The reliability of microfocous X-radiography for detecting subsurface voids in structural ceramic test specimens was statistically evaluated. The microfocus system was operated in the projection mode using low X-ray photon energies (20 keV) and a 10 micro m focal spot. The statistics were developed for implanted subsurface voids in green and sintered silicon carbide and silicon nitride test specimens. These statistics were compared with previously-obtained statistics for implanted surface voids in similar specimens. Problems associated with void implantation are discussed. Statistical results are given as probability-of-detection curves at a 95 precent confidence level for voids ranging in size from 20 to 528 micro m in diameter.

Probability of detection of internal voids in structural ceramics using microfocus radiography

NASA Technical Reports Server (NTRS)

Baaklini, G. Y.; Roth, D. J.

1985-01-01

The reliability of microfocus x-radiography for detecting subsurface voids in structural ceramic test specimens was statistically evaluated. The microfocus system was operated in the projection mode using low X-ray photon energies (20 keV) and a 10 micro m focal spot. The statistics were developed for implanted subsurface voids in green and sintered silicon carbide and silicon nitride test specimens. These statistics were compared with previously-obtained statistics for implanted surface voids in similar specimens. Problems associated with void implantation are discussed. Statistical results are given as probability-of-detection curves at a 95 percent confidence level for voids ranging in size from 20 to 528 micro m in diameter.

The development of efficient numerical time-domain modeling methods for geophysical wave propagation

NASA Astrophysics Data System (ADS)

Zhu, Lieyuan

This Ph.D. dissertation focuses on the numerical simulation of geophysical wave propagation in the time domain including elastic waves in solid media, the acoustic waves in fluid media, and the electromagnetic waves in dielectric media. This thesis shows that a linear system model can describe accurately the physical processes of those geophysical waves' propagation and can be used as a sound basis for modeling geophysical wave propagation phenomena. The generalized stability condition for numerical modeling of wave propagation is therefore discussed in the context of linear system theory. The efficiency of a series of different numerical algorithms in the time-domain for modeling geophysical wave propagation are discussed and compared. These algorithms include the finite-difference time-domain method, pseudospectral time domain method, alternating directional implicit (ADI) finite-difference time domain method. The advantages and disadvantages of these numerical methods are discussed and the specific stability condition for each modeling scheme is carefully derived in the context of the linear system theory. Based on the review and discussion of these existing approaches, the split step, ADI pseudospectral time domain (SS-ADI-PSTD) method is developed and tested for several cases. Moreover, the state-of-the-art stretched-coordinate perfect matched layer (SCPML) has also been implemented in SS-ADI-PSTD algorithm as the absorbing boundary condition for truncating the computational domain and absorbing the artificial reflection from the domain boundaries. After algorithmic development, a few case studies serve as the real-world examples to verify the capacities of the numerical algorithms and understand the capabilities and limitations of geophysical methods for detection of subsurface contamination. The first case is a study using ground penetrating radar (GPR) amplitude variation with offset (AVO) for subsurface non-aqueous-liquid (NAPL) contamination. The numerical AVO study reveals that the normalized residual polarization (NRP) variation with offset does not respond to subsurface NAPL existence when the offset is close to or larger than its critical value (which corresponds to critical incident angle) because the air and head waves dominate the recorded wave field and severely interfere with reflected waves in the TEz wave field. Thus it can be concluded that the NRP AVO/GPR method is invalid when source-receiver angle offset is close to or greater than its critical value due to incomplete and severely distorted reflection information. In other words, AVO is not a promising technique for detection of the subsurface NAPL, as claimed by some researchers. In addition, the robustness of the newly developed numerical algorithms is also verified by the AVO study for randomly-arranged layered media. Meanwhile, this case study also demonstrates again that the full-wave numerical modeling algorithms are superior to ray tracing method. The second case study focuses on the effect of the existence of a near-surface fault on the vertically incident P- and S- plane waves. The modeling results show that both P-wave vertical incidence and S-wave vertical incidence cases are qualified fault indicators. For the plane S-wave vertical incidence case, the horizontal location of the upper tip of the fault (the footwall side) can be identified without much effort, because all the recorded parameters on the surface including the maximum velocities and the maximum accelerations, and even their ratios H/V, have shown dramatic changes when crossing the upper tip of the fault. The centers of the transition zone of the all the curves of parameters are almost directly above the fault tip (roughly the horizontal center of the model). Compared with the case of the vertically incident P-wave source, it has been found that the S-wave vertical source is a better indicator for fault location, because the horizontal location of the tip of that fault cannot be clearly identified with the ratio of the horizontal to vertical velocity for the P-wave incident case.

Aqueous Alteration on Mars: Evidence from Landed Missions

NASA Technical Reports Server (NTRS)

Ming, Douglas W.; Morris, Richard V.; Clark, Benton C., III; Yen, Albert S.; Gellert, Ralf

2015-01-01

Mineralogical and geochemical data returned by orbiters and landers over the past 15 years have substantially enhanced our understanding of the history of aqueous alteration on Mars. Here, we summarize aqueous processes that have been implied from data collected by landed missions. Mars is a basaltic planet. The geochemistry of most materials has not been “extensively” altered by open-system aqueous processes and have average Mars crustal compositions. There are few examples of open-system alteration, such as Gale crater’s Pahrump Hills mudstone. Types of aqueous alteration include (1) acid-sulfate and (2) hydrolytic (circum-neutral/alkaline pH) with varying water-to-rock ratios. Several hypotheses have been suggested for acid-sulfate alteration including (1) oxidative weathering of ultramafic igneous rocks containing sulfides; (2) sulfuric acid weathering of basaltic materials; (3) acid fog weathering of basaltic materials; and (4) near-neutral pH subsurface solutions rich in Fe (sup 2 plus) that rapidly oxidized to Fe (sup 3 plus) producing excess acidity. Meridiani Planum’s sulfate-rich sedimentary deposit containing jarosite is the most “famous” acid-sulfate environment visited on Mars, although ferric sulfate-rich soils are common in Gusev crater’s Columbia Hills and jarosite was recently discovered in the Pahrump Hills. An example of aqueous alteration under circum-neutral pH conditions is the formation of Fe-saponite with magnetite in situ via aqueous alteration of olivine in Gale crater’s Sheepbed mudstone. Circum-neutral pH, hydrothermal conditions were likely required for the formation of Mg-Fe carbonate in the Columbia Hills. Diagenetic features (e.g., spherules, fracture filled veins) indicate multiple episodes of aqueous alteration/diagenesis in most sedimentary deposits. However, low water-to-rock ratios are prominent at most sites visited by landed missions (e.g., limited water for reaction to form crystalline phases possibly resulting in large amounts of short-range ordered materials and little physical separation of primary and secondary materials). Most of the aqueous alteration appears to have occurred early in the planet’s history; however, minor aqueous alteration may be occurring at the surface today (e.g., thin films of water forming carbonates akin to those discovered by Phoenix).

Effect of synthetic iron colloids on the microbiological NH(4)(+) removal process during groundwater purification.

PubMed

Wolthoorn, Anke; Temminghoff, Erwin J M; van Riemsdijk, Willem H

2004-04-01

Subsurface aeration is used to oxidise Fe in situ in groundwater that is used to make drinking water potable. In a groundwater system with pH>7 subsurface aeration results in non-mobile Fe precipitate and mobile Fe colloids. Since originally the goal of subsurface aeration is to remove iron in situ, the formation of non-mobile iron precipitate, which facilitates the metal's removal, is the desired result. In addition to this intended effect, subsurface aeration may also strongly enhance the microbiological removal of ammonium (NH(4)(+)) in the purification station. Mobile iron colloids could be the link between subsurface aeration and the positive effect on the NH(4)(+) removal process. Therefore, the objective of this study was to assess whether synthetic iron colloids could improve the NH(4)(+) removal process. The effect of synthetic iron colloids on the NH(4)(+) removal process was studied using an artificial purification set-up on a laboratory scale. Columns that purified groundwater with or without added synthetic iron colloids were set up in duplicate. The results showed that the NH(4)(+) removal was significantly ( alpha = 0.05 ) increased in columns treated with the synthetic iron colloids. Cumulative after 4 months about 10% more NH(4)(+) was nitrified in the columns that was treated with the groundwater containing synthetic iron colloids. The results support the hypothesis that mobile iron colloids could be the link between subsurface aeration and the positive effect on the NH(4)(+) removal process.

Line-scan spatially offset Raman spectroscopy for inspecting subsurface food safety and quality

USDA-ARS?s Scientific Manuscript database

This paper presented a method for subsurface food inspection using a newly developed line-scan spatially offset Raman spectroscopy (SORS) technique. A 785 nm laser was used as a Raman excitation source. The line-shape SORS data was collected in a wavenumber range of 0–2815 cm-1 using a detection mod...

Magnetic perturbation inspection of inner bearing races

NASA Technical Reports Server (NTRS)

Barton, J. R.; Lankford, J.

1972-01-01

Approximately 100 inner race bearings were inspected nondestructively prior to endurance testing. Two of the bearings which failed during testing spalled at the sites of subsurface inclusions previously detected by using magnetic field perturbation. At other sites initially judged to be suspect, subsurface inclusion-nucleated cracking was observed. Inspection records and metallurgical sectioning results are presented and discussed.

Analysis of a PAH-degrading bacterial population in subsurface sediments on the Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Shao, Zongze; Cui, Zhisong; Dong, Chunming; Lai, Qiliang; Chen, Liang

2010-05-01

Little is known about the types and concentrations of polycyclic aromatic hydrocarbons (PAHs) existing in the deep-sea subsurface environment, which is believed to be cold, oligothrophic and of high static pressure. PAHs in the upper layers of the water column are unavoidably subjected to degradation while they are deposited to the sea floor and become embedded in the deep-sea sediment. In this report, a high concentration of PAHs was discovered in the sediment 2.7 m beneath the bottom surface at a water depth of 3962 m on the Mid-Atlantic Ridge (MAR). The total concentration of PAHs was 445 ng (g dry wt sediment) -1. Among the seven detected PAHs, the concentrations of phenanthrene (222 ng g -1) and fluorene (79 ng g -1) were relatively high. In addition, PAH-degrading bacteria were found within the sediments. As in a previously detected site on the MAR, in the PAH-enriched region of this site, a bacterium of the genus Cycloclasticus was found to be the predominant isolate detected by PCR-DGGE analysis. In addition, bacteria of the Halomonas, Marinobacter, Alcanivorax, Thalassospira and Maricaulis genera, were also included in the PAH-degrading community. In summary, a high concentration of PAHs was detected in the subsurface of the deep-sea sediment, and once again, the Cycloclasticus bacterium was confirmed to be a ubiquitous marine PAH degrader even in the subsurface marine environment. Considering the abundance of PAHs therein, biodegradation is thus thought to be inactive, probably because of the low temperature, limited oxygen and/or limited nutrients.

NONDESTRUCTIVE TESTING (NDT) TECHNIQUES TO DETECT CONTAINED SUBSURFACE HAZARDOUS WASTE

EPA Science Inventory

The project involves the detection of buried containers with NDT (remote-sensing) techniques. Seventeen techniques were considered and four were ultimately decided upon. They were: electromagnetic induction (EMI); metal detection (MD); magnetometer (MAG); and ground penetrating r...

A theoretical study of the effect of a non-aqueous proton donor on electrochemical ammonia synthesis

DOE PAGES

Zhang, Linan; Mallikarjun Sharada, Shaama; Singh, Aayush R.; ...

2018-01-17

We report that ammonia synthesis is one of the most studied reactions in heterogeneous catalysis. To date, however, electrochemical N 2 reduction in aqueous systems has proven to be extremely difficult, mainly due to the competing hydrogen evolution reaction (HER). Recently, it has been shown that transition metal complexes based on molybdenum can reduce N 2 to ammonia at room temperature and ambient pressure in a non-aqueous system, with a relatively small amount of hydrogen output. We demonstrate that the non-aqueous proton donor they have chosen, 2,6-lutidinium (LutH +), is a viable substitute for hydronium in the electrochemical process atmore » a solid surface, since this donor can suppress the HER rate. Finally, we also show that the presence of LutH + can selectively stabilize the *NNH intermediate relative to *NH or *NH 2via the formation of hydrogen bonds, indicating that the use of non-aqueous solvents can break the scaling relationship between limiting potential and binding energies.« less

A theoretical study of the effect of a non-aqueous proton donor on electrochemical ammonia synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Linan; Mallikarjun Sharada, Shaama; Singh, Aayush R.

We report that ammonia synthesis is one of the most studied reactions in heterogeneous catalysis. To date, however, electrochemical N 2 reduction in aqueous systems has proven to be extremely difficult, mainly due to the competing hydrogen evolution reaction (HER). Recently, it has been shown that transition metal complexes based on molybdenum can reduce N 2 to ammonia at room temperature and ambient pressure in a non-aqueous system, with a relatively small amount of hydrogen output. We demonstrate that the non-aqueous proton donor they have chosen, 2,6-lutidinium (LutH +), is a viable substitute for hydronium in the electrochemical process atmore » a solid surface, since this donor can suppress the HER rate. Finally, we also show that the presence of LutH + can selectively stabilize the *NNH intermediate relative to *NH or *NH 2via the formation of hydrogen bonds, indicating that the use of non-aqueous solvents can break the scaling relationship between limiting potential and binding energies.« less

A New Sensitive GC-MS-based Method for Analysis of Dipicolinic Acid and Quantifying Bacterial Endospores in Deep Marine Subsurface Sediment

NASA Astrophysics Data System (ADS)

Fang, J.

2015-12-01

Marine sediments cover more than two-thirds of the Earth's surface and represent a major part of the deep biosphere. Microbial cells and microbial activity appear to be widespread in these sediments. Recently, we reported the isolation of gram-positive anaerobic spore-forming piezophilic bacteria and detection of bacterial endospores in marine subsurface sediment from the Shimokita coalbed, Japan. However, the modern molecular microbiological methods (e.g., DNA-based microbial detection techniques) cannot detect bacterial endospore, because endospores are impermeable and are not stained by fluorescence DNA dyes or by ribosomal RNA staining techniques such as catalysed reporter deposition fluorescence in situ hybridization. Thus, the total microbial cell abundance in the deep biosphere may has been globally underestimated. This emphasizes the need for a new cultivation independent approach for the quantification of bacterial endospores in the deep subsurface. Dipicolinic acid (DPA, pyridine-2,6-dicarboxylic acid) is a universal and specific component of bacterial endospores, representing 5-15wt% of the dry spore, and therefore is a useful indicator and quantifier of bacterial endospores and permits to estimate total spore numbers in the subsurface biosphere. We developed a sensitive analytical method to quantify DPA content in environmental samples using gas chromatography-mass spectrometry. The method is sensitive and more convenient in use than other traditional methods. We applied this method to analyzing sediment samples from the South China Sea (obtained from IODP Exp. 349) to determine the abundance of spore-forming bacteria in the deep marine subsurface sediment. Our results suggest that gram-positive, endospore-forming bacteria may be the "unseen majority" in the deep biosphere.

Multi-modality analysis of glucose aqueous solution using photoacoustic and dielectric spectroscopy for non-invasive glucose monitoring

NASA Astrophysics Data System (ADS)

Tajima, Takuro; Tanaka, Yujiro; Nakamura, Masahito; Seyama, Michiko

2017-03-01

Quantitative analysis of glucose using conventional optical spectroscopy suffers from a lack of repeatability due to high optical scattering in skin tissue. Here we present a multi-modality analysis of glucose aqueous solution using photoacoustic spectroscopy (PAS) and broadband dielectric spectroscopy (BDS). These techniques involve the direct detection of the acoustic and electromagnetic waves propagating through or reflecting from tissue without their being scattered. They therefore have potential for better tolerance to the variation of scattering. For PAS, to differentiate signals induced by water absorption, we select another laser wavelength (1.38 μm) that exhibits the same absorbance for water at 1.61 μm. Furthermore, one of the two photoacoustic signals is used to normalize the variations of acoustic properties in differential signal. Measured results for glucose solutions (0-2 g/dL) showed that the differential signal has a sensitivity of 1.61%/g·dL-1 and a detection limit of 120 mg/dL. We also tested glucose detection with BDS (500 MHz to 50 GHz) by detecting glucose hydration bonding at around 10-20 GHz. Using a partial least square analysis and first derivation on broadband spectra, we obtained an RMS error 19 mg/dL and a detection limit of 59 mg/dL. Using both the low-scattering ultrasonic and microwave detection techniques, we successfully captured the glucose footprint in the physiological range.

Determining the 3D Subsurface Density Structure of Taurus Littrow Valley Using Apollo 17 Gravity Data

NASA Technical Reports Server (NTRS)

Urbancic, N.; Ghent, R.; Stanley, S,; Johnson, C. L.; Carroll, K. A.; Hatch, D.; Williamson, M. C.; Garry, W. B.; Talwani, M.

2016-01-01

Surface gravity surveys can detect subsurface density variations that can reveal subsurface geologic features. In 1972, the Apollo 17 (A17) mission conducted the Traverse Gravimeter Experiment (TGE) using a gravimeter that measured the local gravity field near Taurus Littrow Valley (TLV), located on the south-eastern rim of the Serenitatis basin. TLV is hypothesized to be a basaltfilled radial graben resulting from the impact that formed Mare Serenitatis. It is bounded by both the North and South Massifs (NM and SM) as well as other smaller mountains to the East that are thought to be mainly composed of brecciated highland material. The TGE is the first and only successful gravity survey on the surface of the Moon. Other more recent satellite surveys, such as NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission (2011- 2012), have produced the best global gravity field to date (approx. 13km resolution). However, these satellite surveys are not sensitive enough to detect fine-scale (<1km) lunar subsurface structures. This underscores the value of the data collected at the surface by A17. In the original analysis of the data a 2D forward-modelling approach was used to derive a thickness of the subsurface basalt layer of 1.0 km by assuming a simple flat-faced rectangular geometry and using densities derived from Apollo lunar samples. We are investigating whether modern 3D modelling techniques in combination with high-resolution topographical and image datasets can reveal additional fine-scale subsurface structure in TLV.

Introduction of a Ground Penetrating Radar System for Subsurface Investigation in Balik Pulau, Penang Island

NASA Astrophysics Data System (ADS)

Teoh, YJ; Bruka, MA; Idris, NM; Ismail, NA; Muztaza, NM

2018-04-01

Ground penetrating radar (GPR) are non-invasive geophysical techniques that enhance studies of the shallow subsurface. The purposes of this work are to study the subsurface composition of Balik Pulau area in Penang Island and to identify shallow subsurface geology features. Data acquisition for GPR is by using 250 MHz antenna to cover 200m survey line at Jalan Tun Sardon, Balik Pulau. GPR survey was divided into ten sections at 20 m each. Results from GPR shows that there is low EM reflection along the first 40 m of the survey line. Intense EM reflections were recorded along the distance 40 m to 100 m. Less noticeable radar reflections recorded along 100 m to 200 m distance of the survey line. As a conclusion, clear signal of radar wave reflection indicates dry region of the subsurface. Meanwhile, low signal of radar wave reflection indicates highly weathered granitic soil or clay of the subsurface.

Increasing subterranean mobilization of organic contaminants and petroleum by aqueous thermal oxidation

DOEpatents

Leif, Roald N.; Knauss, Kevin G.; Newmark, Robin L.; Aines, Roger D.; Eaker, Craig

2002-01-01

In situ hydrous pyrolysis/partial oxidation of organics at the site of the organics constrained in an subsurface reservoir produces surfactants that can form an oil/water emulsion that is effectively removed from an underground formation. The removal of the oil/water emulsions is particularly useful in several applications, e.g., soil contaminant remediation and enhanced oil recovery operations. A portion of the constrained organics react in heated reservoir water with injected steam containing dissolved oxygen gas at ambient reservoir conditions to produce such surfactants.

76 FR 70057 - National Oil and Hazardous Substance Pollution Contingency Plan; National Priorities List...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-10

... surface soils, subsurface soils, structures and groundwater within the boundaries of these parcels. In... soils, subsurface soils, structures and groundwater within the boundaries of the non-ETA part of PIN 05... additional contaminated groundwater and soil within the Site. On November 25, 2005 EPA partially deleted the...

Assessment of Mitigation Systems on Vapor Intrusion: Temporal Trends, Attenuation Factors, and Contaminant Migration Routes under Mitigated and Non-mitigated Conditions

EPA Science Inventory

Vapor intrusion is the migration of subsurface vapors, including radon and volatile organic compounds (VOCs), in soil gas from the subsurface to indoor air. Vapor intrusion happens because there are pressure and concentration differentials between indoor air and soil gas. Indoor ...

Single cell genomic study of Dehalococcoidites in deep sea sediments of Peru Margin 1230

NASA Astrophysics Data System (ADS)

Kaster, A.; Meyer-Blackwell, K.; Spormann, A. M.

2013-12-01

Dehalogenating Chloroflexi, such as Dehalococcoidites Dhc were originally discovered as the key microorganisms mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene. Molecular and genomic studies on their key enzymes for energy conservation, reductive dehalogenases rdh, have provided evidence for ubiquitous horizontal gene transfer. A pioneering study by Futagami et al. discovered novel putative rdh phylotypes in sediments from the Pacific, revealing an unknown and surprising abundance of rdh genes in pristine habitats. The frequent detection of Dhc-related 16S rRNA genes from these environments implied the occurrence of dissimilatory dehalorespiration in marine subsurface sediments, however, pristine Dhc could never be linked to this activity. Despite being ubiquitous in those environments, metabolic life style or ecological function of Dhc in the absence of anthropogenic contaminants is still completely unknown. We therefore analyzed a non-contaminated deep sea sediment sample of the Peru Margin 1230 site by a single cell genomic (SGC) approach. We present for the first time data on three single Dhc cells, helping to elucidate their role in the poorly understood oligotrophic marine sub-surface environment.

Seasonal GPR Signal Changes in Two Contrasting Soils in the Shale Hills Catchment

NASA Astrophysics Data System (ADS)

Lin, H.; Zhang, J.; Doolittle, J. A.

2011-12-01

Repeated GPR surveys in different seasons, combined with real-time soil water monitoring, provide a useful methodology to reveal subsurface hydrologic processes and their underlying mechanisms in different soils and hillslopes. This was demonstrated in the Shale Hills Critical Zone Observatory using two contrasting soils over several dry and wet seasons. Our results showed that 1) the radar reflection in the BC-C horizon interface in the deep Rushtown soil became clearer as soil became wetter, which was linked to lateral flow above this horizon interface that increased the contrast, and 2) the reflection in the soil-bedrock interface and the weathered-unweathered rock interface in the shallow Weikert soil become intermittent as soil became wetter, which was attributed to non-uniform distribution of water in bedrock fractures that created locally strong contrast, leading to point scatter of GPR reflection. This study shows the optimal time for using GPR to detect soil horizon interfaces, the value of nondestructive mapping of soil-rock moisture distribution patterns, and the possibility of identifying preferential flow pathways in the subsurface.

Hybrid CARS for Non-Invasive Blood Glucose Monitoring

NASA Astrophysics Data System (ADS)

Wang, Xi; Pestov, Dmitry; Zhang, Aihua; Murawski, Robert; Sokolov, Alexei; Welch, George; Laane, Jaan; Scully, Marlan

2007-10-01

We develop a spectroscopy technique that combines the advantages of both the frequency-resolved coherent anti-Stokes Raman scattering (CARS) and the time-resolved CARS. We use broadband preparation pulses to get an instantaneous coherent excitation of multiplex molecular vibration levels and subsequent optically shaped time-delayed narrowband probing pulse to detect these vibrations. This technique can suppress the nonresonant background and retrieve the molecular fingerprint signal efficiently and rapidly. We employ this technique to glucose detection, the final goal of which is accurate, non-invasive (i.e. painless) and continuous monitoring of blood glucose concentration in the Diabetes diagnosis to replace the current glucose measurement process, which requires painful fingerpricks and therefore cannot be performed more than a few times a day. We have gotten the CARS spectra of glucose aqueous solution down to 2 mM.

Electrically Conducting, Ca-Rich Brines, Rather Than Water, Expected in the Martian Subsurface

NASA Technical Reports Server (NTRS)

Burt, D. M.; Knauth, L. P.

2003-01-01

If Mars ever possessed a salty liquid hydrosphere, which later partly evaporated and froze down, then any aqueous fluids left near the surface could have evolved to become dense eutectic brines. Eutectic brines, by definition, are the last to freeze and the first to melt. If CaC12-rich, such brines can remain liquid until temperatures below 220 K, close to the average surface temperature of Mars. In the Martian subsurface, in intimate contact with the Ca-rich basaltic regolith, NaC1-rich early brines should have reacted to become Ca-rich. Fractional crystallization (freezing) and partial melting would also drive brines toward CaC12-rich compositions. In other words, eutectic brine compositions could be present in the shallow subsurface of Mars, for the same reasons that eutectic magma compositions are common on Earth. Don Juan Pond, Antarctica, a CaC12-rich eutectic brine, provides a possible terrestrial analog, particularly because it is fed from a basaltic aquifer. Owing to their relative density and fluid nature, brines in the Martian regolith should eventually become sandwiched between ice above and salts beneath. A thawing brine sandwich provides one explanation (among many) for the young gullies recently attributed to seepage of liquid water on Mars. Whether or not brine seepage explains the gullies phenomenon, dense, CaC12-rich brines are to be expected in the deep subsurface of Mars, although they might be somewhat diluted (temperatures permitting) and of variable salt composition. In any case, they should be good conductors of electricity.

Using Electromagnetic Induction Technique to Detect Hydropedological Dynamics: Principles and Applications

NASA Astrophysics Data System (ADS)

Zhu, Qing; Liao, Kaihua; Doolittle, James; Lin, Henry

2014-05-01

Hydropedological dynamics including soil moisture variation, subsurface flow, and spatial distributions of different soil properties are important parameters in ecological, environmental, hydrological, and agricultural modeling and applications. However, technical gap exists in mapping these dynamics at intermediate spatial scale (e.g., farm and catchment scales). At intermediate scales, in-situ monitoring provides detailed data, but is restricted in number and spatial coverage; while remote sensing provides more acceptable spatial coverage, but has comparatively low spatial resolution, limited observation depths, and is greatly influenced by the surface condition and climate. As a non-invasive, fast, and convenient geophysical tool, electromagnetic induction (EMI) measures soil apparent electrical conductivity (ECa) and has great potential to bridge this technical gap. In this presentation, principles of different EMI meters are briefly introduced. Then, case studies of using repeated EMI to detect spatial distributions of subsurface convergent flow, soil moisture dynamics, soil types and their transition zones, and different soil properties are presented. The suitability, effectiveness, and accuracy of EMI are evaluated for mapping different hydropedological dynamics. Lastly, contributions of different hydropedological and terrain properties on soil ECa are quantified under different wetness conditions, seasons, and land use types using Classification and Regression Tree model. Trend removal and residual analysis are then used for further mining of EMI survey data. Based on these analyses, proper EMI survey designs and data processing are proposed.

Highly enhanced optical properties of indocyanine green/perfluorocarbon nanoemulsions for efficient lymph node mapping using near-infrared and magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Bae, Pan Kee; Jung, Juyeon; Chung, Bong Hyun

2014-03-01

The near-infrared (NIR) fluorescence probe has better tissue penetration and lower autofluorescence. Indocyanine green (ICG) is an NIR organic dye for extensive biological application, and it has been clinically approved for human medical imaging and diagnosis. However, application of this dye is limited by its numerous disadvantageous properties in aqueous solution, including its concentration-dependent aggregation, poor aqueous stability in vitro, and low quantum yield. Its use in molecular imaging probes is limited because it loses fluorescence after binding to nonspecific plasma proteins, leading to rapid elimination from the body with a half-life of 2 - 4 min. In this study, the multifunctional perfluorocarbon (PFC)/ICG nanoemulsions were investigated with the aim of overcoming these limitations. The PFC/ICG nanoemulsions as a new type of delivery vehicle for contrast agents have both NIR optical imaging and 19 F-MR imaging moieties. These nanoemulsions exhibited less aggregation, increased fluorescence intensity, long-term stability, and physicochemical stability against external light and temperature compared to free aqueous ICG. Also, the PFC/ICG bimodal nanoemulsions allow excellent detection of lymph nodes in vivo through NIR optical imaging and 19 F-MR imaging. This result showed the suitability of the proposed nanoemulsions for non-invasive lymph node mapping as they enable long-time detection of lymph nodes.

Detection of low amount of irradiated ingredients in non-irradiated precooked meals

NASA Astrophysics Data System (ADS)

Marchioni, Eric; Horvatovich, Peter; Ndiaye, Bara; Miesch, Michel; Hasselmann, Claude

2002-03-01

The application of the European Standards for the detection of irradiated food by thermoluminescence of silicates, electron-spin resonance spectroscopy of bones or gas chromatography-mass spectrometry of 2-alkylcyclobutanones does not allow the detection of irradiated ingredients included in small quantity in the matrix of a food which has not been irradiated, but which could be subjected to various processing technologies such as cooking, freezing or storage. The use of an enzymatic food hydrolysis carried out at moderated temperature, for the extraction of the food-contaminating silicate minerals and bone fragments, followed by a purification of the extracts by a high-density aqueous solution of sodium polytungstate, allows a simultaneous detection of weak inclusions (0.1% m:m) of irradiated spices and mechanically deboned turkey meat (MRM) included in various precooked foods. Moreover, the use of a supercritical fluid extraction procedure for the 2-alkylcyclobutanones or an additional purification step of the lipid extracts made it possible to lower the detection limit of the 2-alkylcyclobutanones radiation-induced from triglycerides. Using gas chromatography-mass spectrometry, down to 0.5% (m:m) of irradiated MRM included in non-irradiated chicken quenelles could be detected.

Exploring the Martian Highlands using a Rover-Deployed Ground Penetrating Radar

NASA Technical Reports Server (NTRS)

Grant, J. A.; Schutz, A. E.; Campbell, B. A.

2001-01-01

The Martian highlands record a long and often complex history of geologic activity that has shaped the planet over time. Results of geologic mapping and new data from the Mars Global Surveyor spacecraft reveal layered surfaces created by multiple processes that are often mantled by eolian deposits. Knowledge of the near-surface stratigraphy as it relates to evolution of surface morphology will provide critical context for interpreting rover/lander remote sensing data and for defining the geologic setting of a highland lander. Rover-deployed ground penetrating radar (GPR) can directly measure the range and character of in situ radar properties, thereby helping to constrain near-surface geology and structure. As is the case for most remote sensing instruments, a GPR may not detect water unambiguously on Mars. Nevertheless, any local, near-surface occurrence of liquid water will lead to large, easily detected dielectric contrasts. Moreover, definition of stratigraphy and setting will help in evaluating the history of aqueous activity and where any water might occur and be accessible. GPR data can also be used to infer the degree of any post-depositional pedogenic alteration or weathering, thereby enabling assessment of pristine versus secondary morphology. Most importantly perhaps, GPR can provide critical context for other rover and orbital instruments/data sets. Hence, rover-deployment of a GPR deployment should enable 3-D mapping of local stratigraphy and could guide subsurface sampling.

Aquatic dissipation of triclopyr in Lake Seminole, Georgia

USGS Publications Warehouse

Woodburn, K.B.; Green, W.R.; Westerdahl, H.E.

1993-01-01

A field study was conducted to evaluate the environmental dissipation of triclopyr herbicide under aquatic-use conditions. Three 4-h plots in Lake Seminole, Georgia, were selected for use: one control, one aerial plot, and one subsurface plot; both applications were at the maximum aquatic-use rate of 2.5 mg/L. Water, sediment, plants, fish, clams, and crayfish were all analyzed for residues, and water temperature, oxygen levels, pH, and conductivity were monitored. The half-life for aqueous-phase triclopyr ranged from 0.5 to 3.6 days, and the dissipation in surface and bottom waters was equivalent. The intermediate decay product of triclopyr, 3,5,6-trichloro-2-pyridinol (TCP), had an observed aquatic half-life of less than 1 day. No accumulation of triclopyr or TCP on sediment was observed. The half-life of triclopyr metabolized by aquatic plants averaged 4 days. Fish species did not exhibit any bioconcentration of triclopyr or TCP, with only trace amounts of either compound found in fish tissue. Both clams and crayfish contained detectable residues of triclopyr. The elimination of triclopyr from clam tissue was more rapid, with an observed half-life of 1.5 days, vs 12 days for crayfish; retention of triclopyr in the crayfish carcass (carapace, chelopeds, and gills) may have been an important mechanism. There was no detectable decline in water quality in either treatment plot. ?? 1993 American Chemical Society.

Recovery Act: Web-based CO{sub 2} Subsurface Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paolini, Christopher; Castillo, Jose

2012-11-30

The Web-based CO{sub 2} Subsurface Modeling project focused primarily on extending an existing text-only, command-line driven, isothermal and isobaric, geochemical reaction-transport simulation code, developed and donated by Sienna Geodynamics, into an easier-to-use Web-based application for simulating long-term storage of CO{sub 2} in geologic reservoirs. The Web-based interface developed through this project, publically accessible via URL http://symc.sdsu.edu/, enables rapid prototyping of CO{sub 2} injection scenarios and allows students without advanced knowledge of geochemistry to setup a typical sequestration scenario, invoke a simulation, analyze results, and then vary one or more problem parameters and quickly re-run a simulation to answer what-if questions.more » symc.sdsu.edu has 2x12 core AMD Opteron™ 6174 2.20GHz processors and 16GB RAM. The Web-based application was used to develop a new computational science course at San Diego State University, COMP 670: Numerical Simulation of CO{sub 2} Sequestration, which was taught during the fall semester of 2012. The purpose of the class was to introduce graduate students to Carbon Capture, Use and Storage (CCUS) through numerical modeling and simulation, and to teach students how to interpret simulation results to make predictions about long-term CO{sub 2} storage capacity in deep brine reservoirs. In addition to the training and education component of the project, significant software development efforts took place. Two computational science doctoral and one geological science masters student, under the direction of the PIs, extended the original code developed by Sienna Geodynamics, named Sym.8. New capabilities were added to Sym.8 to simulate non-isothermal and non-isobaric flows of charged aqueous solutes in porous media, in addition to incorporating HPC support into the code for execution on many-core XSEDE clusters. A successful outcome of this project was the funding and training of three new computational science students and one geological science student in technologies relevant to carbon sequestration and problems involving flow in subsurface media. The three computational science students are currently finishing their doctorial studies on different aspects of modeling CO{sub 2} sequestration, while the geological science student completed his master’s thesis in modeling the thermal response of CO{sub 2} injection in brine and, as a direct result of participation in this project, is now employed at ExxonMobil as a full-time staff geologist.« less

Organic non-aqueous cation-based redox flow batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Lu; Huang, Jinhua; Burrell, Anthony

The present invention provides a non-aqueous redox flow battery comprising a negative electrode immersed in a non-aqueous liquid negative electrolyte, a positive electrode immersed in a non-aqueous liquid positive electrolyte, and a cation-permeable separator (e.g., a porous membrane, film, sheet, or panel) between the negative electrolyte from the positive electrolyte. During charging and discharging, the electrolytes are circulated over their respective electrodes. The electrolytes each comprise an electrolyte salt (e.g., a lithium or sodium salt), a transition-metal free redox reactant, and optionally an electrochemically stable organic solvent. Each redox reactant is selected from an organic compound comprising a conjugated unsaturatedmore » moiety, a boron cluster compound, and a combination thereof. The organic redox reactant of the positive electrolyte comprises a tetrafluorohydroquinone ether compound or a tetrafluorocatechol ether compound.« less

Coupling of non-aqueous electrokinetic chromatography using cationic cyclodextrins with electrospray ionization mass spectrometry.

PubMed

Mol, Roelof; de Jong, Gerhardus J; Somsen, Govert W

2008-01-01

Non-aqueous electrokinetic chromatography (NAEKC) using cationic cyclodextrins (CDs) was coupled to electrospray ionization mass spectrometry (ESI-MS). A methanolic background electrolyte (BGE) was used which contained the hydrochloride salts of the single-isomer derivative cyclodextrins 6-monodeoxy-6-mono(2-hydroxy)propylamino-beta-cyclodextrin (IPA-beta-CD) or 6-monodeoxy-6-mono(3-hydroxy)propylamino-beta-cyclodextrin (PA-beta-CD). Applying a reversed capillary electrophoresis (CE) polarity (-30 kV), efficient separation of negatively charged compounds was achieved with plate numbers of up to 190,000. PA-beta-CD appeared to be the most suitable for the separation of various acidic drugs while also providing a high chiral selectivity. Analyte detection was achieved by ESI-MS in the negative-ion mode using a sheath-liquid interface. In order to prevent current drops caused by the cathodic electroosmotic flow, a pressure of 15 mbar was applied on the inlet vial during NAEKC/MS analysis. The effect of the cationic CDs on the MS signal intensities of acidic test drugs was thoroughly studied. When a voltage is applied across the CE capillary, the overall mobility of the cationic CDs is towards the inlet vial so that no CD molecules enter the ion source. The chloride counter ions of the CDs, which migrated towards the capillary outlet, were found to cause ionization suppression, although significant analyte signals could still be detected. Depending on the CD concentration in the BGE, limits of detection for acidic drugs were in the 50-400 ng/mL range in full-scan mode.

The role of Leptospira spp. in horses affected with recurrent uveitis in the UK.

PubMed

Malalana, F; Blundell, R J; Pinchbeck, G L; Mcgowan, C M

2017-11-01

Equine recurrent uveitis (ERU) is a common cause of ocular pain and blindness in horses. Leptospira spp. have been commonly implicated in the pathophysiology of ERU in mainland Europe and the USA. No recent studies have been carried out in the UK, but Leptospira is reported not to be a major factor in the aetiology of ERU in the UK. To establish the prevalence of Leptospira-associated ERU in the UK and to identify the serovars involved in these cases; to compare serum vs. aqueous humour antibody levels in cases and controls in order to confirm the diagnosis of Leptospira-associated ERU, and to assess the usefulness of serology alone as a confirmatory test for Leptospira-associated ERU in the UK. Case-control study. Eyes enucleated for clinical reasons in ERU-affected horses were collected. Blood and aqueous humour were obtained to determine antibody levels against a variety of Leptospira serovars and C-values (aqueous humour value/serum value) were calculated. In addition, eyes, blood and aqueous humour were obtained from control cases for comparison. Histopathology was performed in all eyes to confirm uveitis in each case. Differences in seroprevalences between ERU and control cases and between Leptospira- and non-Leptospira-associated ERU cases were calculated. A total of 30 ERU and 43 control eyes were analysed. Of the ERU eyes, only two had a C-value of >4 (prevalence of Leptospira-associated uveitis: 6.7%). Serovars hardjo and javanica were detected. There was no difference in seroprevalence between horses with uveitis and control cases (65.5% and 41.9%, respectively; P = 0.11) or between Leptospira- and non-Leptospira-associated uveitis cases (100% and 63.0%, respectively; P = 0.52). The study was limited by low case numbers. Eyes were presented at different stages of disease. The only test used to detect Leptospira was the microscopic agglutination test. Leptospira-associated ERU is uncommon in the UK. Serology alone may not help to definitively diagnose Leptospira-associated uveitis in this country. © 2017 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.

Buried nonmetallic object detection using bistatic ground penetrating radar with variable antenna elevation angle and height

NASA Astrophysics Data System (ADS)

Zhang, Yu; Orfeo, Dan; Burns, Dylan; Miller, Jonathan; Huston, Dryver; Xia, Tian

2017-04-01

Ground penetrating radar (GPR) has been shown to be an effective device for detecting buried objects that have little or no metal content, such as plastic, ceramic, and concrete pipes. In this paper, buried non-metallic object detection is evaluated for different antenna elevation angles and heights using a bistatic air-launched GPR. Due to the large standoff distance between antennas and the ground surface, the air-launched GPR has larger spreading loss than the hand-held GPR and vehicle-mounted GPR. Moreover, nonmetallic objects may have similar dielectric property to the buried medium, which results in further difficulty for accurate detection using air-launched GPR. To study such effects, both GPR simulations and GPR laboratory experiments are performed with various setups where antennas are placed at different heights and angles. In the experiments, the test surface areas are configured with and without rocks in order to examine surface clutter effect. The experimental results evaluate the feasibility and effectiveness of bistatic air-launched GPR for detecting buried nonmetallic objects, which provide valuable insights for subsurface scanning with unmanned aerial vehicle (UAV) mounted GPR.

Subsurface In Situ Elemental Composition Measurements with PING

NASA Technical Reports Server (NTRS)

Parsons, Ann; McClanahan, Timothy; Bodnarik, Julia; Evans, Larry; Nowicki, Suzanne; Schweitzer, Jeffrey; Starr, Richard

2013-01-01

This paper describes the Probing In situ with Neutron and Gamma rays (PING) instrument, that can measure the subsurface elemental composition in situ for any rocky body in the solar system without the need for digging into the surface. PING consists of a Pulsed Neutron Generator (PNG), a gamma ray spectrometer and neutron detectors. Subsurface elements are stimulated by high-energy neutrons to emit gamma rays at characteristic energies. This paper will show how the detection of these gamma rays results in a measurement of elemental composition. Examples of the basalt to granite ratios for aluminum and silicon abundance are provided.

Surface and subsurface sensor performance in acoustically detecting western drywood termites in naturally infested boards.

Treesearch

V.R. Lewis; A.B. Power; M.I. Haverty

2004-01-01

Field-collected boards showing visual signs of damage by the western drywood termite, Incisitermes minor, were searched with a portable acoustic emission (AE) device. Depending on cross-sectional size, boards were either searched with a flat sensor that was hot-melt-glued to the wood surface or a subsurface sensor that wasthreaded 20 mm into the...

Subsurface ice and brine sampling using an ultrasonic/sonic gopher for life detection and characterization in the McMurdo Dry Valleys

NASA Technical Reports Server (NTRS)

Bar-Cohen, Y.; Sherrit, S.; Chang, Z.; Wessel, L.; Bao, X.; Doran, P. T.; Fritsen, C. H.; Kenig, F.; McKay, C. P.; Murray, A.;

Methane clathrate stability zone variations and gas transport in the Martian subsurface

NASA Astrophysics Data System (ADS)

Karatekin, O.; Gloesener, E.; Dehant, V. M. A.; Temel, O.

2016-12-01

During the last years, several detections of methane in the atmosphere of Mars were reported from Earth-based and Mars orbit instruments with abundances ranging to tens of parts-per-billion by volume (ppbv). Recently, the Curiosity rover detected methane with background levels of 0.7 ppbv and episodic releases of 7 ppbv. Although the methane sources are still unknown, this gas may have been stored in reservoirs of clathrate hydrate in the Martian subsurface where thermodynamics conditions are favourable to their presence. Clathrate hydrates are crystalline compounds constituted by cages formed by hydrogen-bonded water molecules inside of which guest gas molecules are trapped. In this study, methane clathrate stability in the Martian subsurface are investigated and their temporal and spatial variations are studied. Present-day maps of methane clathrate stability zone are produced by coupling the stability conditions of methane clathrate with a subsurface model using the available observations such as the the thermal inertia derived from TES MGS data. Then, a gas transport model has been used to study the methane flux at the surface due to the diffusion of different plausible methane volumes released by clathrate hydrates at variable depths under the Martian surface.

Integrating spatial and temporal oxygen data to improve the quantification of in situ petroleum biodegradation rates.

PubMed

Davis, Gregory B; Laslett, Dean; Patterson, Bradley M; Johnston, Colin D

2013-03-15

Accurate estimation of biodegradation rates during remediation of petroleum impacted soil and groundwater is critical to avoid excessive costs and to ensure remedial effectiveness. Oxygen depth profiles or oxygen consumption over time are often used separately to estimate the magnitude and timeframe for biodegradation of petroleum hydrocarbons in soil and subsurface environments. Each method has limitations. Here we integrate spatial and temporal oxygen concentration data from a field experiment to develop better estimates and more reliably quantify biodegradation rates. During a nine-month bioremediation trial, 84 sets of respiration rate data (where aeration was halted and oxygen consumption was measured over time) were collected from in situ oxygen sensors at multiple locations and depths across a diesel non-aqueous phase liquid (NAPL) contaminated subsurface. Additionally, detailed vertical soil moisture (air-filled porosity) and NAPL content profiles were determined. The spatial and temporal oxygen concentration (respiration) data were modeled assuming one-dimensional diffusion of oxygen through the soil profile which was open to the atmosphere. Point and vertically averaged biodegradation rates were determined, and compared to modeled data from a previous field trial. Point estimates of biodegradation rates assuming no diffusion ranged up to 58 mg kg(-1) day(-1) while rates accounting for diffusion ranged up to 87 mg kg(-1) day(-1). Typically, accounting for diffusion increased point biodegradation rate estimates by 15-75% and vertically averaged rates by 60-80% depending on the averaging method adopted. Importantly, ignoring diffusion led to overestimation of biodegradation rates where the location of measurement was outside the zone of NAPL contamination. Over or underestimation of biodegradation rate estimates leads to cost implications for successful remediation of petroleum impacted sites. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Role of Microbial Exopolymeric Substances (EPS) on Chromium Sorption and Transport in Heterogeneous Subsurface Soils: I. Cr(III) Complexation with EPS in Aqueous Solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

C Kantar; H Demiray; N Dogan

2011-12-31

Chromium (III) binding by exopolymeric substances (EPS) isolated from Pseudomonas putida P18, Pseudomonas aeruginosa P16 and Pseudomonas stutzeri P40 strains were investigated by the determination of conditional stability constants and the concentration of functional groups using the ion-exchange experiments and potentiometric titrations. Spectroscopic (EXAFS) analysis was also used to obtain information on the nature of Cr(III) binding with EPS functional groups. The data from ion-exchange experiments and potentiometric titrations were evaluated using a non-electrostatic discrete ligand approach. The modeling results show that the acid/base properties of EPSs can be best characterized by invoking four different types of acid functional groupsmore » with arbitrarily assigned pK{sub a} values of 4, 6, 8 and 10. The analysis of ion-exchange data using the discrete ligand approach suggests that while the Cr binding by EPS from P. aeruginosa can be successfully described based on a reaction stoichiometry of 1:2 between Cr(III) and HL{sub 2} monoprotic ligands, the accurate description of Cr binding by EPSs extracted from P. putida and P. stutzeri requires postulation of 1:1 Cr(III)-ligand complexes with HL{sub 2} and HL{sub 3} monoprotic ligands, respectively. These results indicate that the carboxyl and/or phosphoric acid sites contribute to Cr(III) binding by microbial EPS, as also confirmed by EXAFS analysis performed in the current study. Overall, this study highlights the need for incorporation of Cr-EPS interactions into transport and speciation models to more accurately assess microbial Cr(VI) reduction and chromium transport in subsurface systems, including microbial reactive treatment barriers.« less

Role of microbial exopolymeric substances (EPS) on chromium sorption and transport in heterogeneous subsurface soils: I. Cr(III) complexation with EPS in aqueous solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kantar, C.; Dodge, C.; Demiray, H.

2011-01-26

Chromium (III) binding by exopolymeric substances (EPS) isolated from Pseudomonas putida P18, Pseudomonas aeruginosa P16 and Pseudomonas stutzeri P40 strains were investigated by the determination of conditional stability constants and the concentration of functional groups using the ion-exchange experiments and potentiometric titrations. Spectroscopic (EXAFS) analysis was also used to obtain information on the nature of Cr(III) binding with EPS functional groups. The data from ion-exchange experiments and potentiometric titrations were evaluated using a non-electrostatic discrete ligand approach. The modeling results show that the acid/base properties of EPSs can be best characterized by invoking four different types of acid functional groupsmore » with arbitrarily assigned pK{sub a} values of 4, 6, 8 and 10. The analysis of ion-exchange data using the discrete ligand approach suggests that while the Cr binding by EPS from P. aeruginosa can be successfully described based on a reaction stoichiometry of 1:2 between Cr(III) and HL{sub 2} monoprotic ligands, the accurate description of Cr binding by EPSs extracted from P. putida and P. stutzeri requires postulation of 1:1 Cr(III)-ligand complexes with HL{sub 2} and HL{sub 3} monoprotic ligands, respectively. These results indicate that the carboxyl and/or phosphoric acid sites contribute to Cr(III) binding by microbial EPS, as also confirmed by EXAFS analysis performed in the current study. Overall, this study highlights the need for incorporation of Cr-EPS interactions into transport and speciation models to more accurately assess microbial Cr(VI) reduction and chromium transport in subsurface systems, including microbial reactive treatment barriers.« less

Study of sorption-retarded U(VI) diffusion in Hanford silt/clay material.

PubMed

Bai, Jing; Liu, Chongxuan; Ball, William P

2009-10-15

A diffusion cell method was applied to measure the effective pore diffusion coefficient (Dp) for U(VI) under strictly controlled chemical conditions in a silt/clay sediment from the U.S. Department of Energy Hanford site, WA. "Inward-flux" diffusion studies were conducted in which [U(VI)] in both aqueous and solid phases was measured as a function of distance in the diffusion cell under conditions of constant concentration at the cell boundaries. A sequential extraction method was developed to measure sorbed contaminant U(VI) in the solid phase containing extractable background U(VI). The effect of sorption kinetics on U(VI) interparticle diffusion was evaluated by comparing sorption-retarded diffusion models with sorption described either as equilibrium or intraparticle diffusion-limited processes. Both experimental and modeling results indicated that (1) a single pore diffusion coefficient can simulate the diffusion of total aqueous U(VI), and (2) the local equilibrium assumption (LEA) is appropriate for modeling sorption-retarded diffusion under the given experimental conditions. Dp of 1.6-1.7 x 10(-6) cm2/s was estimated in aqueous solution at pH 8.0 and saturated with respect to calcite, as relevant to some subsurface regions of the Hanford site.

Evaluation of a predictive ground-water solute-transport model at the Idaho National Engineering Laboratory, Idaho

USGS Publications Warehouse

Lewis, Barney D.; Goldstein, Flora J.

1982-01-01

Aqueous chemical and radioactive wastes discharged to shallow ponds and to shallow or deep wells on the Idaho National Engineering Laboratory (INEL) since 1952 have affected the quality of the ground water in the underlying Snake River Plain aquifer. The aqueous wastes have created large and laterally dispersed concentration plumes within the aquifer. The waste plumes with the largest areal distribution are those of chloride , tritium, and with high specific conductance values. The data from eight wells drilled near the southern INEL boundary during the summer of 1980 were used to evaluate the accuracy of a predictive modeling study completed in 1973, and to simulate 1980 positions of chloride and tritium plumes. Data interpretation from the drilling program indicates that the hydrogeologic characteristics of the subsurface rocks have marked effects on the regional ground-water flow regimen and, therefore, the movement of aqueous wastes. As expected, the waste plumes projected by the computer model for 1980, extended somewhat further downgradient than indicated by well data due to conservative worst-case assumptions in the model input and inacurate approximations of subsequent waste discharge and aquifer recharge conditions. (USGS)

Patterns and drivers of bacterial α- and β-diversity across vertical profiles from surface to subsurface sediments.

PubMed

Luna, Gian Marco; Corinaldesi, Cinzia; Rastelli, Eugenio; Danovaro, Roberto

2013-10-01

We investigated the patterns and drivers of bacterial α- and β-diversity, along with viral and prokaryotic abundance and the carbon production rates, in marine surface and subsurface sediments (down to 1 m depth) in two habitats: vegetated sediments (seagrass meadow) and non-vegetated sediments. Prokaryotic abundance and production decreased with depth in the sediment, but cell-specific production rates and the virus-to-prokaryote ratio increased, highlighting unexpectedly high activity in the subsurface. The highest diversity was observed in vegetated sediments. Bacterial β-diversity between sediment horizons was high, and only a minor number of taxa was shared between surface and subsurface layers. Viruses significantly contributed to explain α- and β-diversity patterns. Despite potential limitations due to the only use of fingerprinting techniques, this study indicates that the coastal subsurface host highly active and diversified bacterial assemblages, that subsurface cells are more active than expected and that viruses promote β-diversity and stimulate bacterial metabolism in subsurface layers. The limited number of taxa shared between habitats, and between surface and subsurface sediment horizons, suggests that future investigations of the shallow subsurface will provide insights into the census of bacterial diversity, and the comprehension of the patterns and drivers of prokaryotic diversity in marine ecosystems. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

Detection of emerging sunspot regions in the solar interior.

PubMed

Ilonidis, Stathis; Zhao, Junwei; Kosovichev, Alexander

2011-08-19

Sunspots are regions where strong magnetic fields emerge from the solar interior and where major eruptive events occur. These energetic events can cause power outages, interrupt telecommunication and navigation services, and pose hazards to astronauts. We detected subsurface signatures of emerging sunspot regions before they appeared on the solar disc. Strong acoustic travel-time anomalies of an order of 12 to 16 seconds were detected as deep as 65,000 kilometers. These anomalies were associated with magnetic structures that emerged with an average speed of 0.3 to 0.6 kilometer per second and caused high peaks in the photospheric magnetic flux rate 1 to 2 days after the detection of the anomalies. Thus, synoptic imaging of subsurface magnetic activity may allow anticipation of large sunspot regions before they become visible, improving space weather forecast.

Mapping Subsurface Structure at Guar Kepah by using Ground Penetrating Radar

NASA Astrophysics Data System (ADS)

Mansor, Hafizuddin; Rosli, Najmiah; Ismail, N. A.; Saidin, M.; Masnan, S. S. K.

2018-04-01

A Ground Penetrating Radar (GPR) survey was conducted at Guar Kepah to detect buried object before commencement of archaeological gallery construction. The study area covered around 20 m length and 14 m width. 15 GPR lines were constructed from north to south with 20 m length, 1 m spacing and parallel to each other. The 500 MHz closed antenna had been used in this study. The surface findings were noticed before started GPR survey. The data was analysed and interpreted by using Groundvision software and several filters were applied to radargrams to enhance the data. Based on the result, several anomalies were detected. The surface findings also detected by GPR which cause hyperbolic curve in radargrams. The subsurface layer was detected by GPR survey. The anomalies are assigned to several classes based on the pattern of signals obtained in radargrams.

Thermoelectric SQUID method for the detection of segregations

NASA Astrophysics Data System (ADS)

Hinken, Johann H.; Tavrin, Yury

2000-05-01

Aero engine turbine discs are most critical parts. Material inhomogeneities can cause disc fractures during the flight with fatal air disasters. Nondestructive testing (NDT) of the discs in various machining steps is necessary and performed as well as possible. Conventional NDT methods, however, like eddy current testing and ultrasonic testing have unacceptable limits. For example, subsurface segregations often cannot be detected directly but only indirectly in such cases when cracks already have developed from them. This may be too late. A new NDT method, which we call the Thermoelectric SQUID Method, has been developed. It allows for the detection of metallic inclusions within non-ferromagnetic metallic base material. This paper describes the results of a feasibility study on aero engine turbine discs made from Inconel® 718. These contained segregations that had been detected before by anodic etching. With the Thermoelectric SQUID Method, these segregations were detected again, and further segregations below the surfaces have been found, which had not been detected before. For this new NDT method the disc material is quasi-transparent. The Thermoelectric SQUID Method is also useful to detect distributed and localized inhomogeneities in pure metals like niobium sheets for particle accelerators.

Sulfate deposition in subsurface regolith in Gusev crater, Mars

USGS Publications Warehouse

Wang, A.; Haskin, L.A.; Squyres, S. W.; Jolliff, B.L.; Crumpler, L.; Gellert, Ralf; Schroder, C.; Herkenhoff, K.; Hurowitz, J.; Tosca, N.J.; Farrand, W. H.; Anderson, R.; Knudson, A.T.

2006-01-01

Excavating into the shallow Martian subsurface has the potential to expose stratigraphic layers and mature regolith, which may hold a record of more ancient aqueous interactions than those expected under current Martian surface conditions. During the Spirit rover's exploration of Gusev crater, rover wheels were used to dig three trenches into the subsurface regolith down to 6-11 cm depth: Road Cut, the Big Hole, and The Boroughs. A high oxidation state of Fe and high concentrations of Mg, S, Cl, and Br were found in the subsurface regolith within the two trenches on the plains, between the Bonneville crater and the foot of Columbia Hills. Data analyses on the basis of geochemistry and mineralogy observations suggest the deposition of sulfate minerals within the subsurface regolith, mainly Mg-sulfates accompanied by minor Ca-sulfates and perhaps Fe-sulfates. An increase of Fe2O3, an excess of SiO2, and a minor decrease in the olivine proportion relative to surface materials are also inferred. Three hypotheses are proposed to explain the geochemical trends observed in trenches: (1) multiple episodes of acidic fluid infiltration, accompanied by in situ interaction with igneous minerals and salt deposition; (2) an open hydrologic system characterized by ion transportation in the fluid, subsequent evaporation of the fluid, and salt deposition; and (3) emplacement and mixing of impact ejecta of variable composition. While all three may have plausibly contributed to the current state of the subsurface regolith, the geochemical data are most consistent with ion transportation by fluids and salt deposition as a result of open-system hydrologic behavior. Although sulfates make up >20 wt.% of the regolith in the wall of The Boroughs trench, a higher hydrated sulfate than kieserite within The Boroughs or a greater abundance of sulfates elsewhere than is seen in The Boroughs wall regolith would be needed to hold the structural water indicated by the water-equivalent hydrogen concentration observed by the Gamma-Ray Spectrometer on Odyssey in the Gusev region. Copyright 2006 by the American Geophysical Union.

Development of anomaly detection models for deep subsurface monitoring

NASA Astrophysics Data System (ADS)

Sun, A. Y.

2017-12-01

Deep subsurface repositories are used for waste disposal and carbon sequestration. Monitoring deep subsurface repositories for potential anomalies is challenging, not only because the number of sensor networks and the quality of data are often limited, but also because of the lack of labeled data needed to train and validate machine learning (ML) algorithms. Although physical simulation models may be applied to predict anomalies (or the system's nominal state for that sake), the accuracy of such predictions may be limited by inherent conceptual and parameter uncertainties. The main objective of this study was to demonstrate the potential of data-driven models for leakage detection in carbon sequestration repositories. Monitoring data collected during an artificial CO2 release test at a carbon sequestration repository were used, which include both scalar time series (pressure) and vector time series (distributed temperature sensing). For each type of data, separate online anomaly detection algorithms were developed using the baseline experiment data (no leak) and then tested on the leak experiment data. Performance of a number of different online algorithms was compared. Results show the importance of including contextual information in the dataset to mitigate the impact of reservoir noise and reduce false positive rate. The developed algorithms were integrated into a generic Web-based platform for real-time anomaly detection.

Structural characterization of environmentally relevant ternary uranyl citrate complexes present in aqueous solutions and solid state materials.

PubMed

Basile, Madeline; Unruh, Daniel K; Flores, Erin; Johns, Adam; Forbes, Tori Z

2015-02-14

Organic acids are important metal chelators in environmental systems and tend to form soluble complexes in aqueous solutions, ultimately influencing the transport and bioavailability of contaminants in surface and subsurface waters. This is particularly true for the formation of uranyl citrate complexes, which have been utilized in advanced photo- and bioremediation strategies for soils contaminated with nuclear materials. Given the complexity of environmental systems, the formation of ternary or heterometallic uranyl species in aqueous solutions are also expected, particularly with Al(iii) and Fe(iii) cations. These ternary forms are reported to be more stable in aqueous solutions, potentially enhancing contaminant mobility and uptake by organisms, but the exact coordination geometries of these soluble molecular complexes have not been elucidated. To provide insight into the nature of these species, we have developed a series of geochemical model compounds ([(UO(2))(2)Al(2)(C(6)H(4)O(7))(4)](6-) (U(2)Al(2)), [(UO(2))(2)Fe(2)(C(6)H(4)O(7))(4)](6-) (U(2)Fe(2)-1) and [(UO(2))(2)Fe(2)(C(6)H(4)O(7))(4)(H(2)O)(2)](6-) (U(2)Fe(2)-2) and [(UO(2))(2)Fe(4)(OH)(4)(C(6)H(4)O(7))(4)](8-) (U(2)Fe(4))) that were characterized by single-crystal X-ray diffraction and vibrational spectroscopy. Mass spectroscopy was then employed to compare the model compounds to species present in aqueous solutions to provide an enhanced understanding of the ternary uranyl citrate complexes that could be relevant in natural systems.

Subsurface Xenon Migration by Atmospheric Pumping Using an Implicit Non-Iterative Algorithm for a Locally 1D Dual-Porosity Model

NASA Astrophysics Data System (ADS)

Annewandter, R.; Kalinowksi, M. B.

2009-04-01

An underground nuclear explosion injects radionuclids in the surrounding host rock creating an initial radionuclid distribution. In the case of fractured permeable media, cyclical changes in atmospheric pressure can draw gaseous species upwards to the surface, establishing a ratcheting pump effect. The resulting advective transport is orders of magnitude more significant than transport by molecular diffusion. In the 1990s the US Department of Energy funded the socalled Non-Proliferation Experiment conducted by the Lawrence Livermore National Laboratory to investigate this barometric pumping effect for verifying compliance with respect to the Comprehensive Nuclear Test Ban Treaty. A chemical explosive of approximately 1 kt TNT-equivalent has been detonated in a cavity located 390 m deep in the Rainier Mesa (Nevada Test Site) in which two tracer gases were emplaced. Within this experiment SF6 was first detected in soil gas samples taken near fault zones after 50 days and 3He after 325 days. For this paper a locally one-dimensional dual-porosity model for flow along the fracture and within the permeable matrix was used after Nilson and Lie (1990). Seepage of gases and diffusion of tracers between fracture and matrix are accounted. The advective flow along the fracture and within the matrix block is based on the FRAM filtering remedy and methodology of Chapman. The resulting system of equations is solved by an implicit non-iterative algorithm. Results on time of arrival and subsurface concentration levels for the CTBT-relevant xenons will be presented.

GPR Technologies and Methodologies in Italy: A Review

NASA Astrophysics Data System (ADS)

Benedetto, Andrea; Frezza, Fabrizio; Manacorda, Guido; Massa, Andrea; Pajewski, Lara

2014-05-01

GPR techniques and technologies have been subject of intense research activities at the Italian level in the last 15 years because of their potential applications specifically to civil engineering. More in detail, several innovative approaches and models have been developed to inspect road pavements to measure the thickness of their layers as well as to diagnose or prevent damage. Moreover, new frontiers in bridge inspection as well as in geotechnical applications such as slides and flows have been investigated using GPR. From the methodological viewpoint, innovative techniques have been developed to solve GPR forward-scattering problems, as well to locate and classify subsurface targets in real-time and to retrieve their properties through multi-resolution strategies, and linear and non-linear methodologies. Furthermore, the application of GPR and other non-destructive testing methods in archaeological prospecting, cultural heritage diagnostics, and in the localization and detection of vital signs of trapped people has been widely investigated. More recently, new theoretical and empirical paradigms regarding water moisture evaluation in various porous media and soil characterization have been published as the results of long terms research activities. Pioneer studies are also currently under development with the scope to correlate GPR measurement with mechanical characteristics of bound and unbound construction materials. In such a framework, this abstract will be aimed at reviewing some of the most recent advances of GPR techniques and technologies within the Italian industrial and academic communities [also including their application within international projects such as FP7 ISTIMES (http://www.istimes.eu)], and at envisaging some of the most promising research trends currently under development. Acknowledgment - This work was supported by COST Action TU1208 'Civil Engineering Applications of Ground Penetrating Radar' References [1] M. Balsi, S. Esposito, F. Frezza, P. Nocito, L. Porrini, L. Pajewski, G. Schettini e C. Twizere, 'FDTD Simulation of GPR Measurements in a Laboratory Sandbox for Landmine Detection', Proc. IWAGPR 2009, Granada, Spagna, 27-29 maggio 2009, pp. 45-49. [2] M. Balsi, S. Esposito, F. Frezza, P. Nocito, P. M. Barone, S. E. Lauro, E. Mattei, E. Pettinelli, G. Schettini e C. Twizere, 'GPR Measurements and FDTD Simulations for Landmine Detection', Proc. XIII International Conference on Ground Penetrating Radar, 21-25 giugno 2010, Lecce, pp. 865-869. [3] M. Balsi, P. M. Barone, S. Esposito, F. Frezza, S. E. Lauro, P. Nocito, E. Pettinelli, G. Schettini e C. Twizere, 'FDTD Simulations and GPR Measurements for Land Mine Detection in a Controlled Environment', Atti XVIII Riunione Nazionale di Elettromagnetismo, Benevento, 6-10 settembre 2010, pp. 59-65. [4] M. Salucci, D. Sartori, N. Anselmi, A. Randazzo, G. Oliveri, and A. Massa, 'Imaging buried objects within the second-order born approximation through a multiresolution regularized Inexact-Newton method', 2013 International Symposium on Electromagnetic Theory (EMTS), (Hiroshima, Japan), May 20-24 2013. [5] L. Lizzi, F. Viani, P. Rocca, G. Oliveri, M. Benedetti and A. Massa, 'Three-dimensional real-time localization of subsurface objects - From theory to experimental validation,' 2009 IEEE International Geoscience and Remote Sensing Symposium, vol. 2, pp. II-121-II-124, 12-17 July 2009. [6] S. Meschino, L. Pajewski, M. Pastorino, A. Randazzo, and G. Schettini, 'Detection of Subsurface Metallic Utilities by Means of a SAP Technique: Comparing MUSIC- and SVM-Based Approaches', J. Appl. Geophy., vol. 97, pp. 60-68, Oct. 2013. [7] M. Pastorino, and A. Randazzo, 'Buried object detection by an Inexact-Newton applied to nonlinear inverse scattering', Int. J. of Microwave Sci. Technol., vol. 2012, Article ID 637301, 7 pages, 2012. [8] F. Soldovieri and L. Crocco, "Electromagnetic Tomography", in Subsurface Sensing, A. S. Turk, K. A. Hocaoglu, A. A. Vertiy ed., Wiley Series in Microwave and Optical Engineering (Volume 1), Sept. 2011, John Wiley & Sons, NY. [9] I. Catapano, L. Crocco, Y. Krellmann, G. Triltzsch, F. Soldovieri, "A Tomographic Approach for Helicopter-Borne Ground Penetrating Radar Imaging", IEEE Geosci. Rem. Sensing Lett., vol. 9, p. 378-382, 2012.

Oxidation of clofibric acid in aqueous solution using a non-thermal plasma discharge or gamma radiation

NASA Astrophysics Data System (ADS)

Madureira, Joana; Ceriani, Elisa; Pinhão, Nuno; Marotta, Ester; Melo, Rita; Cabo Verde, Sandra; Paradisi, Cristina; Margaça, Fernanda M. A.

2017-11-01

In this work, we study degradation of clofibric acid (CFA) in aqueous solution using either ionizing radiation from a $^{60}$Co source or a non-thermal plasma produced by discharges in the air above the solution. The results obtained with the two technologies are compared in terms of effectiveness of CFA degradation and its by-products. In both cases the CFA degradation follows a quasi-exponential decay in time well modelled by a kinetic scheme which considers the competition between CFA and all reaction intermediates for the reactive species generated in solution as well as the amount of the end product formed. A new degradation law is deduced to explain the results. Although the end-product CO$_2$ was detected and the CFA conversion found to be very high under the studied conditions, HPLC analysis reveals several degradation intermediates still bearing the aromatic ring with the chlorine substituent. The extent of mineralization is rather limited. The energy yield is found to be higher in the gamma radiation experiments.

Oxidation of clofibric acid in aqueous solution using a non-thermal plasma discharge or gamma radiation.

PubMed

Madureira, Joana; Ceriani, Elisa; Pinhão, Nuno; Marotta, Ester; Melo, Rita; Cabo Verde, Sandra; Paradisi, Cristina; Margaça, Fernanda M A

2017-11-01

In this work, we study degradation of clofibric acid (CFA) in aqueous solution using either ionizing radiation from a 60 Co source or a non-thermal plasma produced by discharges in the air above the solution. The results obtained with the two technologies are compared in terms of effectiveness of CFA degradation and its by-products. In both cases the CFA degradation follows a quasi-exponential decay in time well modelled by a kinetic scheme which considers the competition between CFA and all reaction intermediates for the reactive species generated in solution as well as the amount of the end product formed. A new degradation law is deduced to explain the results. Although the end-product CO 2 was detected and the CFA conversion found to be very high under the studied conditions, HPLC analysis reveals several degradation intermediates still bearing the aromatic ring with the chlorine substituent. The extent of mineralization is rather limited. The energy yield is found to be higher in the gamma radiation experiments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dissolution Kinetics of Meta-Torbernite under Circum-neutral to Alkaline Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wellman, Dawn M.; McNamara, Bruce K.; Bacon, Diana H.

2009-12-21

Autunite group minerals have been identified in contaminated sediments as the long-term controlling phase of uranium. Meta-torbernite, has been identified in subsurface environments which were subjected to co-contaminant disposal practices from past nuclear weapons and fuel operations. Under these conditions the mobility of uranium in subsurface pore waters is limited by the rate of meta-torbernite dissolution; however, there are no known investigations which report the dissolution behavior of meta-torbernite. The purpose of this investigation was to conduct a series of single-pass flow-through (SPFT) tests to 1) quantify the effect of temperature (23 - 90oC) and pH (6 -10) on meta-torbernitemore » dissolution, 2) compare the dissolution of meta-torbernite to other autunite-group minerals, and 3) evaluate the effect of aqueous phosphate on the dissolution kinetics of meta-torbernite. Results presented here illustrate meta-torbernite dissolution rates increase by ~100X over the pH interval of 6 to 10 (eta = 0.59 ± 0.07), irrespective of temperature. The power law coefficient for meta-torbernite, eta = 0.59 ± 0.07, is greater than that quantified for Ca-meta-autunite, eta = 0.42 ± 0.12. This suggests the stability of meta-torbernite is greater than that of meta-autunite, which is reflected in the predicted stability constants. The rate equation for the dissolution of meta-torbernite as a function of aqueous phosphate concentration is log rdissol (mol m-2 sec-1) = -4.7 x 10-13 + 4.1 x 10-10 [PO43-].« less

Adsorption of non-ionic ABC triblock copolymers: Surface modification of TiO2 suspensions in aqueous and non-aqueous medium

NASA Astrophysics Data System (ADS)

Lerch, Jean-Philippe; Atanase, Leonard Ionut; Riess, Gérard

2017-10-01

A series of non-ionic ABC triblock copolymers, such as poly(butadiene)-b-poly(2-vinylpyrridine)-b-poly(ethylene oxide) (PB-P2VP-PEO) were synthesized by sequential anionic polymerizations. For these copolymers comprising an organo-soluble PB and a water-soluble PEO block, their P2VP middle block has been selected for its anchoring capacity on solid surfaces. The adsorption isotherms on TiO2 were obtained in heptane and in aqueous medium, as selective solvents. In both of these cases, the P2VP middle block provides the surface anchoring, whereas PB and PEO sequences are acting as stabilizing moieties in heptane and water respectively. By extension to ABC triblock copolymers of the scaling theory developed for diblock copolymers, the density of adsorbed chains could be correlated with the molecular characteristics of the PB-P2VP-PEO triblock copolymers. From a practical point a view, it could be demonstrated that these copolymers are efficient dispersing agents for the TiO2 pigments in both aqueous and non-aqueous medium.

Lock-in thermographic inspection of squats on rail steel head

NASA Astrophysics Data System (ADS)

Peng, D.; Jones, R.

2013-03-01

The development of squat defects has become a major concern in numerous railway systems throughout the world. Infrared thermography is a relatively new non-destructive inspection technique used for a wide range of applications. However, it has not been used for rail squat detection. Lock-in thermography is a non-destructive inspection technique that utilizes an infrared camera to detect the thermal waves. A thermal image is produced, which displays the local thermal wave variation in phase or amplitude. In inhomogeneous materials, the amplitude and phase of the thermal wave carries information related to both the local thermal properties and the nature of the structure being inspected. By examining the infrared thermal signature of squat damage on the head of steel rails, it was possible to generate a relationship matching squat depth to thermal image phase angle, using appropriate experimental/numerical calibration. The results showed that with the additional data sets obtained from further experimental tests, the clarity of this relationship will be greatly improved to a level whereby infrared thermal contours can be directly translated into the precise subsurface behaviour of a squat.

The IUPAC aqueous and non-aqueous experimental pKa data repositories of organic acids and bases.

PubMed

Slater, Anthony Michael

2014-10-01

Accurate and well-curated experimental pKa data of organic acids and bases in both aqueous and non-aqueous media are invaluable in many areas of chemical research, including pharmaceutical, agrochemical, specialty chemical and property prediction research. In pharmaceutical research, pKa data are relevant in ligand design, protein binding, absorption, distribution, metabolism, elimination as well as solubility and dissolution rate. The pKa data compilations of the International Union of Pure and Applied Chemistry, originally in book form, have been carefully converted into computer-readable form, with value being added in the process, in the form of ionisation assignments and tautomer enumeration. These compilations offer a broad range of chemistry in both aqueous and non-aqueous media and the experimental conditions and original reference for all pKa determinations are supplied. The statistics for these compilations are presented and the utility of the computer-readable form of these compilations is examined in comparison to other pKa compilations. Finally, information is provided about how to access these databases.

The IUPAC aqueous and non-aqueous experimental pKa data repositories of organic acids and bases

NASA Astrophysics Data System (ADS)

Slater, Anthony Michael

2014-10-01

Accurate and well-curated experimental pKa data of organic acids and bases in both aqueous and non-aqueous media are invaluable in many areas of chemical research, including pharmaceutical, agrochemical, specialty chemical and property prediction research. In pharmaceutical research, pKa data are relevant in ligand design, protein binding, absorption, distribution, metabolism, elimination as well as solubility and dissolution rate. The pKa data compilations of the International Union of Pure and Applied Chemistry, originally in book form, have been carefully converted into computer-readable form, with value being added in the process, in the form of ionisation assignments and tautomer enumeration. These compilations offer a broad range of chemistry in both aqueous and non-aqueous media and the experimental conditions and original reference for all pKa determinations are supplied. The statistics for these compilations are presented and the utility of the computer-readable form of these compilations is examined in comparison to other pKa compilations. Finally, information is provided about how to access these databases.

Structural and spectroscopic studies of a rare non-oxido V(v) complex crystallized from aqueous solution

DOE PAGES

Leggett, Christina J.; Parker, Bernard F.; Teat, Simon J.; ...

2016-01-14

A “bare” V 5+ complex with glutaroimide-dioxime (H 3L), a ligand for uranium recovery from seawater, was synthesized from aqueous solution as Na[V(L) 2]2H 2O and the structure determined by x-ray diffraction. It is the first non-oxo V(v) complex that has been directly synthesized in and crystallized from aqueous solution.

Structural and spectroscopic studies of a rare non-oxido V(v) complex crystallized from aqueous solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leggett, Christina J.; Parker, Bernard F.; Teat, Simon J.

A “bare” V 5+ complex with glutaroimide-dioxime (H 3L), a ligand for uranium recovery from seawater, was synthesized from aqueous solution as Na[V(L) 2]2H 2O and the structure determined by x-ray diffraction. It is the first non-oxo V(v) complex that has been directly synthesized in and crystallized from aqueous solution.

Fibre optic confocal imaging (FOCI) for subsurface microscopy of the colon in vivo.

PubMed Central

Delaney, P M; King, R G; Lambert, J R; Harris, M R

1994-01-01

Fibre optic confocal imaging (FOCI) is a new type of microscopy which has been recently developed (Delaney et al. 1993). In contrast to conventional light microscopy, FOCI and other confocal techniques allow clear imaging of subsurface structures within translucent objects. However, unlike conventional confocal microscopes which are bulky (because of a need for accurate alignment of large components) FOCI allows the imaging end to be miniaturised and relatively mobile. FOCI is thus particularly suited for clear subsurface imaging of structures within living animals or subjects. The aim of the present study was to assess the suitability of using FOCI for imaging of subsurface structures within the colon, both in vitro (human and rat biopsies) and in vivo (in rats). Images were obtained in fluorescence mode (excitation 488 nm, detection above 515 nm) following topical application of fluorescein. By this technique the glandular structure of the colon was imaged. FOCI is thus suitable for subsurface imaging of the colon in vivo. Images Fig. 2 Fig. 3 PMID:8157487

Evaluation of cytotoxic effects and acute and chronic toxicity of aqueous extract of the seeds of Calycotome villosa (Poiret) Link (subsp. intermedia) in rodents.

PubMed

Lyoussi, Badiaa; Cherkaoui Tangi, Khadija; Morel, Nicole; Haddad, Mohamed; Quetin-Leclercq, Joelle

2018-01-01

The present investigation was carried out to evaluate the safety of an aqueous extract of the seeds of Calycotome villosa (Poiret) Link (subsp. intermedia) by determining its cytotoxicity and potential toxicity after acute and sub-chronic administration in rodents. Cytotoxic activity was tested in cancer and non-cancer cell lines HeLa, Mel-5, HL-60 and 3T3. Acute toxicity tests were carried out in mice by a single oral administration of Calycotome seed-extract (0 - 12 g/kg) as well as intraperitoneal doses of 0 - 5 g/kg. Sub-chronic studies were conducted in Wistar rats by administration of oral daily doses for up to 90 days. Changes in body and vital organ weights, mortality, haematology, clinical biochemistry and histologic morphology were evaluated. The lyophilized aqueous extract of C. villosa exhibited a low cytotoxicity in all cell lines tested with an IC 50 > 100 µg/ml. In the acute study in mice, intra-peritoneal administration caused dose-dependent adverse effects and mortality with an LD 50 of 4.06 ± 0.01 g/kg. In the chronic tests, neither mortality nor visible signs of lethality was seen in rats. Even AST and ALT were not affected while a significant decrease in serum glucose levels, at 300 and 600 mg/kg was detected. Histopathological examination of the kidney and liver did not show any alteration or inflammation at the end of treatment. In conclusion, the aqueous extract of C. villosa seed appeared to be non-toxic and did not produce mortality or clinically significant changes in the haematological and biochemical parameters in rats.

Optical fiber-mediated photosynthesis for enhanced subsurface oxygen delivery.

PubMed

Lanzarini-Lopes, Mariana; Delgado, Anca G; Guo, Yuanming; Dahlen, Paul; Westerhoff, Paul

2018-03-01

Remediation of polluted groundwater often requires oxygen delivery into subsurface to sustain aerobic bacteria. Air sparging or injection of oxygen containing solutions (e.g., hydrogen peroxide) into the subsurface are common. In this study visible light was delivered into the subsurface using radially emitting optical fibers. Phototrophic organisms grew near the optical fiber in a saturated sand column. When applying light in on-off cycles, dissolved oxygen (DO) varied from super saturation levels of >15 mg DO/L in presence of light to under-saturation (<5 mg DO/L) in absence of light. Non-photosynthetic bacteria dominated at longer radial distances from the fiber, presumably supported by soluble microbial products produced by the photosynthetic microorganisms. The dissolved oxygen variations alter redox condition changes in response to light demonstrate the potential to biologically deliver oxygen into the subsurface and support a diverse microbial community. The ability to deliver oxygen and modulate redox conditions on diurnal cycles using solar light may provide a sustainable, long term strategy for increasing dissolved oxygen levels in subsurface environments and maintaining diverse biological communities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Patterns in coupled water and energy cycle: Modeling, synthesis with observations, and assessing the subsurface-landsurface interactions

NASA Astrophysics Data System (ADS)

Rahman, A.; Kollet, S. J.; Sulis, M.

2013-12-01

In the terrestrial hydrological cycle, the atmosphere and the free groundwater table act as the upper and lower boundary condition, respectively, in the non-linear two-way exchange of mass and energy across the land surface. Identifying and quantifying the interactions among various atmospheric-subsurface-landsurface processes is complicated due to the diverse spatiotemporal scales associated with these processes. In this study, the coupled subsurface-landsurface model ParFlow.CLM was applied over a ~28,000 km2 model domain encompassing the Rur catchment, Germany, to simulate the fluxes of the coupled water and energy cycle. The model was forced by hourly atmospheric data from the COSMO-DE model (numerical weather prediction system of the German Weather Service) over one year. Following a spinup period, the model results were synthesized with observed river discharge, soil moisture, groundwater table depth, temperature, and landsurface energy flux data at different sites in the Rur catchment. It was shown that the model is able to reproduce reasonably the dynamics and also absolute values in observed fluxes and state variables without calibration. The spatiotemporal patterns in simulated water and energy fluxes as well as the interactions were studied using statistical, geostatistical and wavelet transform methods. While spatial patterns in the mass and energy fluxes can be predicted from atmospheric forcing and power law scaling in the transition and winter months, it appears that, in the summer months, the spatial patterns are determined by the spatially correlated variability in groundwater table depth. Continuous wavelet transform techniques were applied to study the variability of the catchment average mass and energy fluxes at varying time scales. From this analysis, the time scales associated with significant interactions among different mass and energy balance components were identified. The memory of precipitation variability in subsurface hydrodynamics acts at the 20-30 day time scale, while the groundwater contribution to sustain the long-term variability patterns in evapotranspiration acts at the 40-60 day scale. Diurnal patterns in connection with subsurface hydrodynamics were also detected. Thus, it appears that the subsurface hydrodynamics respond to the temporal patterns in land surface fluxes due to the variability in atmospheric forcing across multiple space and time scales.

Issues Involving The OSI Concept of Operation For Noble Gas Radionuclide Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carrigan, C R; Sun, Y

2011-01-21

The development of a technically sound protocol for detecting the subsurface release of noble gas radionuclides is critical to the successful operation of an on site inspection (OSI) under the CTBT and has broad ramifications for all aspects of the OSI regime including the setting of specifications for both sampling and analysis equipment used during an OSI. With NA-24 support, we are investigating a variety of issues and concerns that have significant bearing on policy development and technical guidance regarding the detection of noble gases and the creation of a technically justifiable OSI concept of operation. The work at LLNLmore » focuses on optimizing the ability to capture radioactive noble gases subject to the constraints of possible OSI scenarios. This focus results from recognizing the difficulty of detecting gas releases in geologic environments - a lesson we learned previously from the LLNL Non-Proliferation Experiment (NPE). Evaluation of a number of important noble gas detection issues, potentially affecting OSI policy, has awaited the US re-engagement with the OSI technical community. Thus, there have been numerous issues to address during the past 18 months. Most of our evaluations of a sampling or transport issue necessarily involve computer simulations. This is partly due to the lack of OSI-relevant field data, such as that provided by the NPE, and partly a result of the ability of LLNL computer-based models to test a range of geologic and atmospheric scenarios far beyond what could ever be studied in the field making this approach very highly cost effective. We review some highlights of the transport and sampling issues we have investigated during the past year. We complete the discussion of these issues with a description of a preliminary design for subsurface sampling that is intended to be a practical solution to most if not all the challenges addressed here.« less

Subsurface defect detection in first layer of pavement structure and reinforced civil engineering structure by FRP bonding using active infrared thermography

NASA Astrophysics Data System (ADS)

Dumoulin, Jean; Ibos, Laurent

2010-05-01

In many countries road network ages while road traffic and maintenance costs increase. Nowadays, thousand and thousand kilometers of roads are each year submitted to surface distress survey. They generally lean on pavement surface imaging measurement techniques, mainly in the visible spectrum, coupled with visual inspection or image processing detection of emergent distresses. Nevertheless, optimisation of maintenance works and costs requires an early detection of defects within the pavement structure when they still are hidden from surface. Accordingly, alternative measurement techniques for pavement monitoring are currently under investigation (seismic methods, step frequency radar). On the other hand, strengthening or retrofitting of reinforced concrete structures by externally bonded Fiber Reinforced Polymer (FRP) systems is now a commonly accepted and widespread technique. However, the use of bonding techniques always implies following rigorous installing procedures. To ensure the durability and long-term performance of the FRP reinforcements, conformance checking through an in situ auscultation of the bonded FRP systems is then highly suitable. The quality-control program should involve a set of adequate inspections and tests. Visual inspection and acoustic sounding (hammer tap) are commonly used to detect delaminations (disbonds) but are unable to provide sufficient information about the depth (in case of multilayered composite) and width of debonded areas. Consequently, rapid and efficient inspection methods are also required. Among the non destructive methods under study, active infrared thermography was investigated both for pavement and civil engineering structures through experiments in laboratory and numerical simulations, because of its ability to be also used on field. Pulse Thermography (PT), Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) approaches have been tested onto pavement samples and CFRP bonding on concrete samples in laboratory. In parallel numerical simulations have been used to generate a set of time sequence of thermal maps for simulated samples with and without subsurface defect. Using this set of experimental and simulated data different approaches (thermal contrast, FFT analysis, polynomial interpolation, singular value decomposition…) for defect location have been studied and compared. Defect depth retrieval was also studied on such data using different thermal model coupled to a direct or an inverse approach. Trials were conducted both with an uncooled and cooled infrared camera with different measurement performances. Results obtained will be discussed and analysed in the paper we plan to present. Finally, combining numerical simulations and experiments allows us discussing on the sensitivity influence of the infrared camera used to detect subsurface defects.

Visual texture for automated characterisation of geological features in borehole televiewer imagery

NASA Astrophysics Data System (ADS)

Al-Sit, Waleed; Al-Nuaimy, Waleed; Marelli, Matteo; Al-Ataby, Ali

2015-08-01

Detailed characterisation of the structure of subsurface fractures is greatly facilitated by digital borehole logging instruments, the interpretation of which is typically time-consuming and labour-intensive. Despite recent advances towards autonomy and automation, the final interpretation remains heavily dependent on the skill, experience, alertness and consistency of a human operator. Existing computational tools fail to detect layers between rocks that do not exhibit distinct fracture boundaries, and often struggle characterising cross-cutting layers and partial fractures. This paper presents a novel approach to the characterisation of planar rock discontinuities from digital images of borehole logs. Multi-resolution texture segmentation and pattern recognition techniques utilising Gabor filters are combined with an iterative adaptation of the Hough transform to enable non-distinct, partial, distorted and steep fractures and layers to be accurately identified and characterised in a fully automated fashion. This approach has successfully detected fractures and layers with high detection accuracy and at a relatively low computational cost.

Near-Infrared Imaging for Detecting Caries and Structural Deformities in Teeth

PubMed Central

Angelino, Keith; Edlund, David A.

2017-01-01

2-D radiographs, while commonly used for evaluating sub-surface hard structures of teeth, have low sensitivity for early caries lesions, particularly those on tooth occlusal surfaces. Radiographs are also frequently refused by patients over safety concerns. Translucency of teeth in the near-infrared (NIR) range offers a non-ionizing and safe approach to detect dental caries. We report the construction of an NIR (850 nm) LED imaging system, comprised of an NIR source and an intraoral camera for rapid dental evaluations. The NIR system was used to image teeth of ten consenting human subjects and successfully detected secondary, amalgam–occluded and early caries lesions without supplementary image processing. The camera-wand system was also capable of revealing demineralized areas, deep and superficial cracks, and other clinical features of teeth usually visualized by X-rays. The NIR system’s clinical utility, simplistic design, low cost, and user friendliness make it an effective dental caries screening technology in conjunction or in place of radiographs. PMID:28507826

Near-Infrared Imaging for Detecting Caries and Structural Deformities in Teeth.

PubMed

Angelino, Keith; Edlund, David A; Shah, Pratik

2017-01-01

2-D radiographs, while commonly used for evaluating sub-surface hard structures of teeth, have low sensitivity for early caries lesions, particularly those on tooth occlusal surfaces. Radiographs are also frequently refused by patients over safety concerns. Translucency of teeth in the near-infrared (NIR) range offers a non-ionizing and safe approach to detect dental caries. We report the construction of an NIR (850 nm) LED imaging system, comprised of an NIR source and an intraoral camera for rapid dental evaluations. The NIR system was used to image teeth of ten consenting human subjects and successfully detected secondary, amalgam-occluded and early caries lesions without supplementary image processing. The camera-wand system was also capable of revealing demineralized areas, deep and superficial cracks, and other clinical features of teeth usually visualized by X-rays. The NIR system's clinical utility, simplistic design, low cost, and user friendliness make it an effective dental caries screening technology in conjunction or in place of radiographs.

Autonomous microexplosives subsurface tracing system final report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engler, Bruce Phillip; Nogan, John; Melof, Brian Matthew

The objective of the autonomous micro-explosive subsurface tracing system is to image the location and geometry of hydraulically induced fractures in subsurface petroleum reservoirs. This system is based on the insertion of a swarm of autonomous micro-explosive packages during the fracturing process, with subsequent triggering of the energetic material to create an array of micro-seismic sources that can be detected and analyzed using existing seismic receiver arrays and analysis software. The project included investigations of energetic mixtures, triggering systems, package size and shape, and seismic output. Given the current absence of any technology capable of such high resolution mapping ofmore » subsurface structures, this technology has the potential for major impact on petroleum industry, which spends approximately $1 billion dollar per year on hydraulic fracturing operations in the United States alone.« less

SUBSURFACE RESIDENCE TIMES AS AN ALGORITHM FOR AQUIFER SENSITIVITY MAPPING: TESTING THE CONCEPT WITH GROUND WATER MODELS IN THE CONTENTNEA CREEK BASIN, NORTH CAROLINA, USA

EPA Science Inventory

This poster will present a modeling and mapping assessment of landscape sensitivity to non-point source pollution as applied to a hierarchy of catchment drainages in the Coastal Plain of the state of North Carolina. Analysis of the subsurface residence time of water in shallow a...

Biofiltration of Volatile Pollutants: Solubility Effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davison, Brian H.; Barton, John W.

2001-06-15

This project investigates and collects fundamental partitioning data for a variety of sparingly soluble subsurface contaminants (e.g., TCE, etc.) between vapor, aqueous phase, and matrices containing substantial quantities of biomass and biomass components. Due to the difficulty of obtaining these measurements, environmental models have generally used solubility constants of chemicals in pure water or, in a few rare cases, simple linear models. Our prior EMSP work has shown that the presence of biological material can increase effective solubilities by an order of magnitude for sparingly soluble organics; therefore, the previous simple approaches are not valid and are extremely poor predictorsmore » of actual bio-influenced partitioning. It is likely that environmental contaminants will partition in a similar manner into high-biomass phases (e.g. biobarriers and plants) or humic soils. Biological material in the subsurface can include lipids, fatty acids, humic materials, as well a s the lumped and difficult to estimate 'biomass'. Our measurements include partition into these biological materials to allow better estimation. Fundamental data collected will be used in mathematical models predicting transport and sorption in subsurface environments, with the impacts on bioremediation being evaluated based on this new information. Our 2-D Win95/98 software program, Biofilter 1.0, developed as a part of our prior EMSP efforts for describing biofiltration processes with consideration given to both kinetic and mass transfer factors, will be extended to incorporate and use this information.« less

Biofiltration of Volatile Pollutants: Solubility Effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davison, Brian H.; Barton, John W.

2002-06-15

This project investigates and collects fundamental partitioning data for a variety of sparingly soluble subsurface contaminants (e.g., TCE, etc.) between vapor, aqueous phase, and matrices containing substantial quantities of biomass and biomass components. Due to the difficulty of obtaining these measurements, environmental models have generally used solubility constants of chemicals in pure water or, in a few rare cases, simple linear models. Our prior EMSP work has shown that the presence of biological material can increase effective solubilities by an order of magnitude for sparingly soluble organics; therefore, the previous simple approaches are not valid and are extremely poor predictorsmore » of actual bio-influenced partitioning. It is likely that environmental contaminants will partition in a similar manner into high-biomass phases (e.g. biobarriers and plants) or humic soils. Biological material in the subsurface can include lipids, fatty acids, humic materials, as well as the lumped and difficult-to-estimate 'biomass'. Our measurements include partition into these biological materials to allow better estimation. Fundamental data collected will be used in mathematical models predicting transport and sorption in subsurface environments, with the impacts on bioremediation being evaluated based on this new information. Our 2-D Win95/98/XP software program, Biofilter 1.0, developed as a part of our prior EMSP efforts for describing biofiltration processes with consideration given to both kinetic and mass transfer factors, is being extended to incorporate and use this information.« less

Coupled three-layer model for turbulent flow over large-scale roughness: On the hydrodynamics of boulder-bed streams

NASA Astrophysics Data System (ADS)

Pan, Wen-hao; Liu, Shi-he; Huang, Li

2018-02-01

This study developed a three-layer velocity model for turbulent flow over large-scale roughness. Through theoretical analysis, this model coupled both surface and subsurface flow. Flume experiments with flat cobble bed were conducted to examine the theoretical model. Results show that both the turbulent flow field and the total flow characteristics are quite different from that in the low gradient flow over microscale roughness. The velocity profile in a shallow stream converges to the logarithmic law away from the bed, while inflecting over the roughness layer to the non-zero subsurface flow. The velocity fluctuations close to a cobble bed are different from that of a sand bed, and it indicates no sufficiently large peak velocity. The total flow energy loss deviates significantly from the 1/7 power law equation when the relative flow depth is shallow. Both the coupled model and experiments indicate non-negligible subsurface flow that accounts for a considerable proportion of the total flow. By including the subsurface flow, the coupled model is able to predict a wider range of velocity profiles and total flow energy loss coefficients when compared with existing equations.

Geomorphological evidence for ground ice on dwarf planet Ceres

USGS Publications Warehouse

Schmidt, Britney E.; Hughson, Kynan H.G.; Chilton, Heather T.; Scully, Jennifer E. C.; Platz, Thomas; Nathues, Andreas; Sizemore, Hanna; Bland, Michael T.; Byrne, Shane; Marchi, Simone; O'Brien, David; Schorghofer, Norbert; Hiesinger, Harald; Jaumann, Ralf; Hendrick Pasckert, Jan; Lawrence, Justin D.; Buzckowski, Debra; Castillo-Rogez, Julie C.; Sykes, Mark V.; Schenk, Paul M.; DeSanctis, Maria-Cristina; Mitri, Giuseppe; Formisano, Michelangelo; Li, Jian-Yang; Reddy, Vishnu; Le Corre, Lucille; Russell, Christopher T.; Raymond, Carol A.

2017-01-01

Five decades of observations of Ceres suggest that the dwarf planet has a composition similar to carbonaceous meteorites and may have an ice-rich outer shell protected by a silicate layer. NASA’s Dawn spacecraft has detected ubiquitous clays, carbonates and other products of aqueous alteration across the surface of Ceres, but surprisingly it has directly observed water ice in only a few areas. Here we use Dawn Framing Camera observations to analyse lobate morphologies on Ceres’ surface and we infer the presence of ice in the upper few kilometres of Ceres. We identify three distinct lobate morphologies that we interpret as surface flows: thick tongue-shaped, furrowed flows on steep slopes; thin, spatulate flows on shallow slopes; and cuspate sheeted flows that appear fluidized. The shapes and aspect ratios of these flows are different from those of dry landslides—including those on ice-poor Vesta—but are morphologically similar to ice-rich flows on other bodies, indicating the involvement of ice. Based on the geomorphology and poleward increase in prevalence of these flows, we suggest that the shallow subsurface of Ceres is comprised of mixtures of silicates and ice, and that ice is most abundant near the poles.

Development of hand-held thermographic inspection technologies.

DOT National Transportation Integrated Search

2009-09-01

This study explored the application of hand-held thermographic cameras for the detection of subsurface delaminations in concrete : bridges. The goal of the research was to provide maintenance and inspection personnel with an effective tool for detect...

Non-aqueous primary cell

NASA Astrophysics Data System (ADS)

James, S. D.; Smith, P. H.; Oneill, K. M.; Wilson, M. H.

1986-05-01

This patent application relates to electrochemical cells and especially to high-energy, liquid cathode, non-aqueous lithium electrochemical cells free from highly toxic materials. A non-aqueous lithium electrochemical cell is described which includes a halocarbon cathode depolarizer which is 1,2-dichloroethane, 1.1,2-trichloroethane, 1,1,2,2-tetrachloroethane, 1,2-dichloro-1,1-difluoroethane or mixtures thereof and a cathode catalyst which is copper, rhodium, palladium, cobalt phthalocyanine, nickel phthalocyanine, iron phthalocyanine, a cobalt tetraaza-(14)-annulene, a nickel tetraaza-(14)-annulene, a iron tetraaza-(14)-annulene, a cobalt porphyrin, a nickel porphyrin, a iron porphyrin, or a mixture thereof.

Optical Detection of Organic Chemical Biosignatures at Hydrothermal Vents

NASA Technical Reports Server (NTRS)

Conrad, P. G.; Lane, A. L.; Bhartia, R.; Hug, W. H.

2004-01-01

We have developed a non-contact, optical life detection instrument that can detect organic chemical biosignatures in a number of different environments, including dry land, shallow aqueous, deep marine or in ice. Hence, the instrument is appropriate as a biosignature survey tool both for Mars exploration or in situ experiments in an ice-covered ocean such as one might wish to explore on Europa. Here, we report the results we obtained on an expedition aboard the Russian oceanographic vessel Akademik Mstislav Keldysh to hydrothermal vent sites in the Pacific Ocean using our life detection instrument MCDUVE, a multichannel, deep ultraviolet excitation fluorescence detector. MCDUVE detected organic material distribution on rocks near the vent, as well as direct detection of organisms, both microbial and microscopic. We also were able to detect organic material issuing directly from vent chimneys, measure the organic signature of the water column as we ascended, and passively observe the emission of light directly from some vents.

Effect of Galla chinensis on the remineralization of two bovine root lesions morphous in vitro.

PubMed

Guo, Bin; Que, Ke-Hua; Jing Yang; Wang, Bo; Liang, Qian-Qian; Xie, Hong-Hui

2012-09-01

The present study aims to evaluate the effect of Galla chinensis compounds on the remineralization of two artificial root lesions morphous in vitro. Sixty bovine dentine blocks were divided into two groups and individually treated with two levels of demineralization solutions to form erosive and subsurface artificial carious lesions in vitro. Each group was then divided into three subgroups, each of which were treated with a remineralization solution (positive control), deionized water (negative control), or 4 000 mg⋅L(-1) aqueous solutions of Galla chinensis extract. The dentine blocks were then subjected to a pH-cycling regime for 7 days. During the first 4 days, the daily cycle included 21-h deal and 3-h demineralization applications. The dentine blocks were dealt with the entire day during the remaining 3 days. Two specimens from each of the treatment groups were selected and observed under a polarized light microscope. Data collected using a laser scanning confocal microscope were computerized and analyzed. Galla chinensis extract clearly enhanced the remineralization of both erosive lesion and subsurface lesion patterns in the specimens (P<0.05). The level of remineralization of the erosive lesion by Galla chinensis extract was lower than that of the subsurface lesion (P<0.05). In addition, the remineralization of the subsurface lesion by Galla chinensis extract was higher than that of the remineralization solution (P<0.05). No significant difference between the remineralization of erosive lesions by Galla chinensis extract and the remineralization solution was observed (P>0.05). So Galla chinensis extract has the potential to improve the remineralization of artificial root lesions under dynamic pH-cyclic conditions, indicating its potential use as a natural remineralization medicine.

The Hydrological Evolution of Mars as Recorded at Gale Crater

NASA Astrophysics Data System (ADS)

Andrews-Hanna, J. C.; Horvath, D. G.

2017-12-01

The sedimentary deposits making up the Aeolis Mons sedimentary mound within Gale Crater preserve a record of the evolving hydrology and climate of Mars during the Late Noachian and Hesperian epochs. Aqueous sedimentary deposits including mudstones, deltaic deposits, and sulfate-cemented sediments indicate the past presence of liquid water on the surface. However, these observations alone do not strictly constrain the nature of the hydrology and climate at the time of deposition. We use models of the subsurface and surface hydrology to shed light on the conditions required to reproduce the observed deposits. Changes in the nature and composition of the deposits reflect changes in the balance between the surface and subsurface components of the hydrological cycle, driven by climate changes. Mudstones observed by the MSL rover at the base of the crater reflect lacustrine deposition under semi-arid conditions, with substantial fluid supply from both the surface (overland flow and direct precipitation) and subsurface. A transition at higher stratigraphic levels to sulfate-cemented sandstones required a change to a more arid climate, with the hydrology dominated by long-distance subsurface transport. Near the top of the mound, unaltered deposits indicate deposition under dry conditions, though this transition coincides with the natural limit on the rise of the water table imposed by the surrounding topography and does not require a change in climate. Erosion of the crater-filling sedimentary deposits to their present mound shape required a dramatic drop in the water table under hyper-arid conditions. Evidence for later lake stands in the Hesperian indicates transient returns to semi-arid conditions similar to those that prevailed during the Late Noachian. By coupling surface and orbital observations with hydrological modeling, we are able to make more specific constraints on the evolving climate and aridity of early Mars.

Efficacy of acetate-amended biostimulation for uranium sequestration: Combined analysis of sediment/groundwater geochemistry and bacterial community structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Jie; Veeramani, Harish; Qafoku, Nikolla P.

Systematic flow-through column experiments were conducted using sediments and ground water collected from different subsurface localities at the U.S. Department of Energy’s Integrated Field Research Challenge site in Rifle, Colorado. The principal purpose of this study is to gain a better understanding of the interactive effects of groundwater geochemistry, sediment mineralogy, and indigenous bacterial community structures on the efficacy of uranium removal from the groundwater with/without acetate amendment. Overall, we find that the subtle variations in the sediments’ mineralogy, particle size, redox conditions, as well as contents of metal(loid) co-contaminants showed a pronounced effect on the associated bacterial population andmore » composition, which mainly determines the system’s performance with respect to uranium removal. Positive relationship was identified between the abundance of dissimilatory sulfate-reduction genes (i.e., drsA), markers of sulfate-reducing bacteria, and the sediments’ propensity to sequester aqueous uranium. In contrast, no obvious connections were observed between the abundance of common iron-reducing bacteria, e.g., Geobacter spp., and the sediments’ ability to sequester uranium. In the sediments with low bacterial biomass and the absence of sulfate-reducing conditions, abiotic adsorption onto mineral surfaces such as phyllosilicates likely played a relatively major role in the attenuation of aqueous uranium; however, in these scenarios, acetate amendment induced detectable rebounds in the effluent uranium concentrations. The results of this study suggest that reductive immobilization of uranium can be achieved under predominantly sulfate-reducing conditions, and provide insight into the integrated roles of various biogeochemical components in long-term uranium sequestration.« less

Quaternary ammonium promoted ultra selective and sensitive fluorescence detection of fluoride ion in water and living cells.

PubMed

Li, Long; Ji, Yuzhuo; Tang, Xinjing

2014-10-21

Highly selective and sensitive fluorescent probes with a quaternary ammonium moiety have been rationally designed and developed for fast and sensitive fluorescence detection of fluoride ion (F(-) from NaF, not TBAF) in aqueous solution and living cells. With the sequestration effect of quaternary ammonium, the detection time was less than 2 min and the detection limit of fluoride ion was as low as 0.57 ppm that is among the lowest detection limits in aqueous solutions of many fluoride fluorescence probes in the literature.

Seismic Characterization of the Blue Mountain Geothermal Site

NASA Astrophysics Data System (ADS)

Templeton, D. C.; Matzel, E.; Cladouhos, T. T.

2017-12-01

All fluid injection activities have the potential to induce earthquakes by modifying the state of stress in the subsurface. In geothermal areas, small microearthquakes can be a beneficial outcome of these stress perturbations by providing direct subsurface information that can be used to better understand and manage the underground reservoir. These events can delineate the active portions of the subsurface that have slipped in response to pore fluid pressure changes or temperature changes during and after fluid injection. Here we investigate the seismic activity within the Blue Mountain Geothermal Power Plant located in Humboldt County, Nevada between December 2015 to May 2016. We compare the effectiveness of direct spatial-temporal cross-correlation templates with Matched Field Processing (MFP) derived templates and compare these results with earthquake detection results from a traditional STA/LTA algorithm. Preliminary results show significant clustering of microearthquakes, most probably influenced by plant operations. The significant increase in data availability that advanced earthquake detection methods can provide improves the statistical analyses of induced seismicity sequences, reveal critical information about the ongoing evolution of the subsurface reservoir, and better informs the construction of models for hazard assessments. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Improved Geologic Interpretation of Non-invasive Electrical Resistivity Imaging from In-situ Samples

NASA Astrophysics Data System (ADS)

Mucelli, A.; Aborn, L.; Jacob, R.; Malusis, M.; Evans, J.

2016-12-01

Non-invasive geophysical techniques are useful in characterizing the subsurface geology without disturbing the environment, however, the ability to interpret the subsurface is enhanced by invasive work. Since geologic materials have electrical resistivity values it allows for a geologic interpretation to be made based on variations of electrical resistivity measured by electrical resistivity imaging (ERI). This study focuses on the pre-characterization of the geologic subsurface from ERI collected adjacent to the Montandon Marsh, a wetland located near Lewisburg, PA within the West Branch of the Susquehanna River watershed. The previous invasive data, boreholes, indicate that the subsurface consists of limestone and shale bedrock overlain with sand and gravel deposits from glacial outwash and aeolian processes. The objective is to improve our understanding of the subsurface at this long-term hydrologic research site by using excavation results, specifically observed variations in geologic materials and electrical resistivity laboratory testing of subsurface samples. The pre-excavation ERI indicated that the shallow-most geologic material had a resistivity value of 100-500 ohm-m. In comparison, the laboratory testing indicated the shallow-most material had the same range of electrical resistivity values depending on saturation levels. The ERI also showed that there was an electrically conductive material, 7 to 70 ohm-m, that was interpreted to be clay and agreed with borehole data, however, the excavation revealed that at this depth range the geologic material varied from stratified clay to clay with cobbles to weathered residual clay. Excavation revealed that the subtle variations in the electrical conductive material corresponded well with the variations in the geologic material. We will use these results to reinterpret previously collected ERI data from the entire long-term research site.

Trans-dimensional Bayesian inversion of airborne electromagnetic data for 2D conductivity profiles

NASA Astrophysics Data System (ADS)

Hawkins, Rhys; Brodie, Ross C.; Sambridge, Malcolm

2018-02-01

This paper presents the application of a novel trans-dimensional sampling approach to a time domain airborne electromagnetic (AEM) inverse problem to solve for plausible conductivities of the subsurface. Geophysical inverse field problems, such as time domain AEM, are well known to have a large degree of non-uniqueness. Common least-squares optimisation approaches fail to take this into account and provide a single solution with linearised estimates of uncertainty that can result in overly optimistic appraisal of the conductivity of the subsurface. In this new non-linear approach, the spatial complexity of a 2D profile is controlled directly by the data. By examining an ensemble of proposed conductivity profiles it accommodates non-uniqueness and provides more robust estimates of uncertainties.

Quantitative subsurface analysis using frequency modulated thermal wave imaging

NASA Astrophysics Data System (ADS)

Subhani, S. K.; Suresh, B.; Ghali, V. S.

2018-01-01

Quantitative depth analysis of the anomaly with an enhanced depth resolution is a challenging task towards the estimation of depth of the subsurface anomaly using thermography. Frequency modulated thermal wave imaging introduced earlier provides a complete depth scanning of the object by stimulating it with a suitable band of frequencies and further analyzing the subsequent thermal response using a suitable post processing approach to resolve subsurface details. But conventional Fourier transform based methods used for post processing unscramble the frequencies with a limited frequency resolution and contribute for a finite depth resolution. Spectral zooming provided by chirp z transform facilitates enhanced frequency resolution which can further improves the depth resolution to axially explore finest subsurface features. Quantitative depth analysis with this augmented depth resolution is proposed to provide a closest estimate to the actual depth of subsurface anomaly. This manuscript experimentally validates this enhanced depth resolution using non stationary thermal wave imaging and offers an ever first and unique solution for quantitative depth estimation in frequency modulated thermal wave imaging.

Sampling Soil CO2 for Isotopic Flux Partitioning: Non Steady State Effects and Methodological Biases

NASA Astrophysics Data System (ADS)

Snell, H. S. K.; Robinson, D.; Midwood, A. J.

2014-12-01

Measurements of δ13C of soil CO2 are used to partition the surface flux into autotrophic and heterotrophic components. Models predict that the δ13CO2 of the soil efflux is perturbed by non-steady state (NSS) diffusive conditions. These could be large enough to render δ13CO2 unsuitable for accurate flux partitioning. Field studies sometimes find correlations between efflux δ13CO2 and flux or temperature, or that efflux δ13CO2 is not correlated as expected with biological drivers. We tested whether NSS effects in semi-natural soil were comparable with those predicted. We compared chamber designs and their sensitivity to changes in efflux δ13CO2. In a natural soil mesocosm, we controlled temperature to generate NSS conditions of CO2 production. We measured the δ13C of soil CO2 using in situ probes to sample the subsurface, and dynamic and forced-diffusion chambers to sample the surface efflux. Over eight hours we raised soil temperature by 4.5 OC to increase microbial respiration. Subsurface CO2 concentration doubled, surface efflux became 13C-depleted by 1 ‰ and subsurface CO2 became 13C-enriched by around 2 ‰. Opposite changes occurred when temperature was lowered and CO2 production was decreasing. Different chamber designs had inherent biases but all detected similar changes in efflux δ13CO2, which were comparable to those predicted. Measurements using dynamic chambers were more 13C-enriched than expected, probably due to advection of CO2 into the chamber. In the mesocosm soil, δ13CO2 of both efflux and subsurface was determined by physical processes of CO2 production and diffusion. Steady state conditions are unlikely to prevail in the field, so spot measurements of δ13CO2 and assumptions based on the theoretical 4.4 ‰ diffusive fractionation will not be accurate for estimating source δ13CO2. Continuous measurements could be integrated over a period suitable to reduce the influence of transient NSS conditions. It will be difficult to disentangle biologically driven changes in soil δ13CO2 from physical controls, particularly as they occur on similar timescales and are driven by the same environmental variables, such as temperature, moisture and daylight.

A size selective porous silicon grating-coupled Bloch surface and sub-surface wave biosensor.

PubMed

Rodriguez, Gilberto A; Ryckman, Judson D; Jiao, Yang; Weiss, Sharon M

2014-03-15

A porous silicon (PSi) grating-coupled Bloch surface and sub-surface wave (BSW/BSSW) biosensor is demonstrated to size selectively detect the presence of both large and small molecules. The BSW is used to sense large immobilized analytes at the surface of the structure while the BSSW that is confined inside but near the top of the structure is used to sensitively detect small molecules. Functionality of the BSW and BSSW modes is theoretically described by dispersion relations, field confinements, and simulated refractive index shifts within the structure. The theoretical results are experimentally verified by detecting two different small chemical molecules and one large 40 base DNA oligonucleotide. The PSi-BSW/BSSW structure is benchmarked against current porous silicon technology and is shown to have a 6-fold higher sensitivity in detecting large molecules and a 33% improvement in detecting small molecules. This is the first report of a grating-coupled BSW biosensor and the first report of a BSSW propagating mode. © 2013 Published by Elsevier B.V.

An HPLC-DAD and LC-MS study of condensation oscillations with S(+)-ketoprofen dissolved in acetonitrile.

PubMed

Sajewicz, Mieczysław; Gontarska, Monika; Kronenbach, Dorota; Berry, Etienne; Kowalska, Teresa

2012-03-01

In our earlier studies, a spontaneous chiral conversion of the selected low-molecular-weight carboxylic acids (i.e., amino acids, hydroxy acids, and profen drugs) dissolved in aqueous ethanol medium, running in vitro was described. Then it became clear that this spontaneous chiral conversion is accompanied by the spontaneous condensation of the discussed compounds. With several acids, it was established that this condensation is also oscillatory in nature. The theoretical models were developed aiming to give a rough explanation of the observed non-linear processes. In this paper, the results of these studies on the dynamics of condensation with S(+)-ketoprofen, a very popular profen drug, when stored for certain amount of time dissolved in a non-aqueous medium (i.e., acetonitrile) is presented. These investigations were carried out with the aid of two independent high-performance liquid chromatographic systems with the diode array detection and of a third high-performance liquid chromatographic system equipped with mass spectrometric detection. In one cycle of chromatographic measurements, it was possible to monitor condensation of S(+)-ketoprofen in 25-min intervals for 30 h, thus obtaining kinetic information on the progress of this process. Mass spectrometric detection confirmed the presence of new species in the stored solution with molecular weights much higher than that of S(+)-ketoprofen, which can be attributed to the condensation products. The obtained data show that condensation of S(+)-ketoprofen dissolved in acetonitrile progresses in a rapid manner, and that the observed oscillatory concentration changes with S(+)-ketoprofen and with the main condensation product characterize with an irregularity and shallow amplitudes. A theoretical model was referenced that jointly describes the oscillatory chiral conversion and the oscillatory condensation with the low-molecular-weight chiral carboxylic acids.

Detection of subsurface-intensified eddies from observations of the sea-surface: a case study for Mediterranean Water Eddies in a long-term high-resolution simulation

NASA Astrophysics Data System (ADS)

Ciani, Daniele; Carton, Xavier; Barbosa Aguiar, Ana Claudia; Peliz, Alvaro; Bashmachnikov, Igor; Ienna, Federico; Chapron, Bertrand

2017-04-01

Subsurface-intensified eddies are ubiquitous in the world ocean. They can be generated by exchanges of water masses between semi-enclosed evaporation basins and the open ocean or by deep convection. Past and recent studies have shown that these eddies are carriers of large amounts of heat and salt, that they are coherent over inter-annual timescales and that they can migrate for several thousands of miles from their origination areas towards the open ocean. Hence, subsurface-intensified eddies can influence the three-dimensional distribution of oceanic tracers at global scale. The synoptic knowledge of the eddies positions and mean pathways is then crucial for evaluating temperature and salinity budgets in the world ocean. At present day, satellite sensors constitute the ideal tool for the synoptic and global scale observations of the ocean. Since they only provide informations on the oceanic surface, we characterized the signatures that subsurface eddies generate at the sea-surface, to determine the extent to which they can be isolated from the surrounding surface turbulence and be considered as a trace of an underlying eddy. We studied the surface signature of subsurface-intensified anticyclones (Mediterranean Water Eddies - Meddies) in a realistic, long-term (20 years) and high resolution simulation (dx = 3 km) based on the ROMS model. The novelty and advantage of this approach is given by the simultaneous availability of the full 3D eddies characteristics, the ones of the background ocean and of the sea-surface (in terms of sea-surface height, temperature and salinity). This also allowed us to speculate on a synergy between different satellite observations for the automatic detection of subsurface eddies from space. The along trajectory properties and surface signatures of more than 90 long-lived Meddies were analyzed. We showed that the Meddies constantly generate positive anomalies in sea-surface height and that these anomalies are principally related to the Meddy potential vorticity structure at depth (around 1000 m below the sea-surface). Such anomalies were long-lived, mostly migrated exhibiting southwestward trajectories, their intensities were O(10 cm) and extended horizontally up to more than 300 km (around 1.5 times the Meddy diameter). On the other hand, the Meddies thermohaline surface signatures proved to be mostly dominated by the local surface conditions and their structure poorly correlated to the Meddy structure at depth (e.g. the Meddy volume-integrated salt and temperature content). These results point out that satellite altimetry is the most suitable approach to track subsurface-intensified eddies from observations of the sea-surface, also encouraging the use of future high-resolution altimetric observations (e.g. SWOT) to detect subsurface oceanic motions from satellite sensors.

Aqueous Geochemical Dynamics at the Coast Range Ophiolite Microbial Observatory and The Case for Subsurface Mixing of Regional Groundwaters

NASA Astrophysics Data System (ADS)

Cardace, D.; Schrenk, M. O.; McCollom, T. M.; Hoehler, T. M.

2017-12-01

Serpentinization is the aqueous alteration (or hydration) of olivine and pyroxene minerals in ultramafic rocks, occurring in the seabed and ultramafic units on continents, such as at the Coast Range Ophiolite (CRO) in northern California, USA. Mineral products of serpentinization include serpentine, magnetite, brucite, talc, oxyhydroxides, carbonates, and diverse clay minerals. Such mineral transformations generate extremely high pH solutions with characteristic cation and dissolved metal loads, transmitting CH4, H2, and CO gas mixtures from depth; deep life in ultramafic terrains is thought to be fueled by chemical energy derived from these geochemical reactions. The installation of 8 groundwater monitoring wells in the CRO has allowed frequent monitoring since 2011. Influx of deeply sourced, serpentinization-influenced waters is evidenced by related geochemical shifts (e.g., pH, oxidation-reduction potential), but is apparently mixing with other, regionally important groundwater types. Evaluation salinity loads in concert with other parameters, we model the mixing scenario of this site of ongoing scientific study and experimentation.

An electromagnetic induction method for underground target detection and characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bartel, L.C.; Cress, D.H.

1997-01-01

An improved capability for subsurface structure detection is needed to support military and nonproliferation requirements for inspection and for surveillance of activities of threatening nations. As part of the DOE/NN-20 program to apply geophysical methods to detect and characterize underground facilities, Sandia National Laboratories (SNL) initiated an electromagnetic induction (EMI) project to evaluate low frequency electromagnetic (EM) techniques for subsurface structure detection. Low frequency, in this case, extended from kilohertz to hundreds of kilohertz. An EMI survey procedure had already been developed for borehole imaging of coal seams and had successfully been applied in a surface mode to detect amore » drug smuggling tunnel. The SNL project has focused on building upon the success of that procedure and applying it to surface and low altitude airborne platforms. Part of SNL`s work has focused on improving that technology through improved hardware and data processing. The improved hardware development has been performed utilizing Laboratory Directed Research and Development (LDRD) funding. In addition, SNL`s effort focused on: (1) improvements in modeling of the basic geophysics of the illuminating electromagnetic field and its coupling to the underground target (partially funded using LDRD funds) and (2) development of techniques for phase-based and multi-frequency processing and spatial processing to support subsurface target detection and characterization. The products of this project are: (1) an evaluation of an improved EM gradiometer, (2) an improved gradiometer concept for possible future development, (3) an improved modeling capability, (4) demonstration of an EM wave migration method for target recognition, and a demonstration that the technology is capable of detecting targets to depths exceeding 25 meters.« less

Detecting subsurface features and distresses of roadways and bridge decks with ground penetrating radar at traffic speed

NASA Astrophysics Data System (ADS)

Liu, Hao; Birken, Ralf; Wang, Ming L.

2017-04-01

This paper presents the detections of the subsurface features and distresses in roadways and bridge decks from ground penetrating radar (GPR) data collected at traffic speed. This GPR system is operated at 2 GHz with a penetration depth of 60 cm in common road materials. The system can collect 1000 traces a second, has a large dynamic range and compact packaging. Using a four channel GPR array, dense spatial coverage can be achieved in both longitudinal and transversal directions. The GPR data contains significant information about subsurface features and distresses resulting from dielectric difference, such as distinguishing new and old asphalt, identification of the asphalt-reinforced concrete (RC) interface, and detection of rebar in bridge decks. For roadways, the new and old asphalt layers are distinguished from the dielectric and thickness discontinuities. The results are complemented by surface images of the roads taken by a video camera. For bridge decks, the asphalt-RC interface is automatically detected by a cross correlation and Hilbert transform algorithms, and the layer properties (e.g., dielectric constant and thickness) can be identified. Moreover, the rebar hyperbolas can be visualized from the GPR B-scan images. In addition, the reflection amplitude from steel rebar can be extracted. It is possible to estimate the rebar corrosion level in concrete from the distribution of the rebar reflection amplitudes.

Performance bounds for matched field processing in subsurface object detection applications

NASA Astrophysics Data System (ADS)

Sahin, Adnan; Miller, Eric L.

1998-09-01

In recent years there has been considerable interest in the use of ground penetrating radar (GPR) for the non-invasive detection and localization of buried objects. In a previous work, we have considered the use of high resolution array processing methods for solving these problems for measurement geometries in which an array of electromagnetic receivers observes the fields scattered by the subsurface targets in response to a plane wave illumination. Our approach uses the MUSIC algorithm in a matched field processing (MFP) scheme to determine both the range and the bearing of the objects. In this paper we derive the Cramer-Rao bounds (CRB) for this MUSIC-based approach analytically. Analysis of the theoretical CRB has shown that there exists an optimum inter-element spacing of array elements for which the CRB is minimum. Furthermore, the optimum inter-element spacing minimizing CRB is smaller than the conventional half wavelength criterion. The theoretical bounds are then verified for two estimators using Monte-Carlo simulations. The first estimator is the MUSIC-based MFP and the second one is the maximum likelihood based MFP. The two approaches differ in the cost functions they optimize. We observe that Monte-Carlo simulated error variances always lie above the values established by CRB. Finally, we evaluate the performance of our MUSIC-based algorithm in the presence of model mismatches. Since the detection algorithm strongly depends on the model used, we have tested the performance of the algorithm when the object radius used in the model is different from the true radius. This analysis reveals that the algorithm is still capable of localizing the objects with a bias depending on the degree of mismatch.

Selective and Sensitive Detection of Heavy Metal Ions in 100% Aqueous Solution and Cells with a Fluorescence Chemosensor Based on Peptide Using Aggregation-Induced Emission.

PubMed

Neupane, Lok Nath; Oh, Eun-Taex; Park, Heon Joo; Lee, Keun-Hyeung

2016-03-15

A fluorescent peptidyl chemosensor for the detection of heavy metal ions in aqueous solution as well as in cells was synthesized on the basis of the peptide receptor for the metal ions using an aggregation-induced emission fluorophore. The peptidyl chemosensor (1) bearing tetraphenylethylene fluorophore showed an exclusively selective turn-on response to Hg(2+) among 16 metal ions in aqueous buffered solution containing NaCl. The peptidyl chemosensor complexed Hg(2+) ions and then aggregated in aqueous buffered solution, resulting in the significant enhancement (OFF-On) of emissions at around 470 nm. The fluorescent sensor showed a highly sensitive response to Hg(2+), and about 1.0 equiv of Hg(2+) was enough for the saturation of the emission intensity change. The detection limit (5.3 nM, R(2) = 0.99) of 1 for Hg(2+) ions was lower than the maximum allowable level of Hg(2+) in drinking water by EPA. Moreover, the peptidyl chemosensor penetrated live cells and detected intracellular Hg(2+) ions by the turn-on response.

Radioiodine sorption/desorption and speciation transformation by subsurface sediments from the Hanford Site.

PubMed

Xu, Chen; Kaplan, Daniel I; Zhang, Saijin; Athon, Matthew; Ho, Yi-Fang; Li, Hsiu-Ping; Yeager, Chris M; Schwehr, Kathleen A; Grandbois, Russell; Wellman, Dawn; Santschi, Peter H

2015-01-01

During the last few decades, considerable research efforts have been extended to identify more effective remediation treatment technologies to lower the (129)I concentrations to below federal drinking water standards at the Hanford Site (Richland, USA). Few studies have taken iodate into consideration, though recently iodate, instead of iodide, was identified as the major species in the groundwater of 200-West Area within the Hanford Site. The objective of this study was thus to quantify and understand aqueous radioiodine species transformations and uptake by three sediments collected from the semi-arid, carbonate-rich environment of the Hanford subsurface. All three sediments reduced iodate (IO3(-)) to iodide (I(-)), but the loamy-sand sediment reduced more IO3(-) (100% reduced within 7 days) than the two sand-textured sediments (∼20% reduced after 28 days). No dissolved organo-iodine species were observed in any of these studies. Iodate uptake Kd values ([Isolid]/[Iaq]; 0.8-7.6 L/kg) were consistently and appreciably greater than iodide Kd values (0-5.6 L/kg). Furthermore, desorption Kd values (11.9-29.8 L/kg) for both iodate and iodide were consistently and appreciably greater than uptake Kd values (0-7.6 L/kg). Major fractions of iodine associated with the sediments were unexpectedly strongly bound, such that only 0.4-6.6 % of the total sedimentary iodine could be exchanged from the surface with KCl solution, and 0-1.2% was associated with Fe or Mn oxides (weak NH2HCl/HNO3 extractable fraction). Iodine incorporated into calcite accounted for 2.9-39.4% of the total sedimentary iodine, whereas organic carbon (OC) is likely responsible for the residual iodine (57.1-90.6%) in sediments. The OC, even at low concentrations, appeared to be controlling iodine binding to the sediments, as it was found that the greater the OC concentrations in the sediments, the greater the values of uptake Kd, desorption Kd, and the greater residual iodine concentrations (non-exchangeable, non-calcite-incorporated and non-Mn, Fe-oxide associated). This finding is of particular interest because it suggests that even very low OC concentrations, <0.2%, may have an impact on iodine geochemistry. The findings that these sediments can readily reduce IO3(-), and that IO3(-) sorbs to a greater extent than I(-), sheds light into earlier unexplained Hanford field data that demonstrated increases in groundwater (127)I(-)/(127)IO3(-) ratios and a decrease groundwater (129)IO3(-) concentrations along a transect away from the point sources, where iodine was primarily introduced as IO3(-). While a majority of the radioiodine does not bind to these alkaline sediments, there is likely a second smaller iodine fraction in the Hanford subsurface that is strongly bound, presumably to the sediment OC (and carbonate) phases. This second fraction may have an impact on establishing remediation goals and performance assessment calculations. Copyright © 2014 Elsevier Ltd. All rights reserved.

Methods for separating medical isotopes using ionic liquids

DOEpatents

Luo, Huimin; Boll, Rose Ann; Bell, Jason Richard; Dai, Sheng

2014-10-21

A method for extracting a radioisotope from an aqueous solution, the method comprising: a) intimately mixing a non-chelating ionic liquid with the aqueous solution to transfer at least a portion of said radioisotope to said non-chelating ionic liquid; and b) separating the non-chelating ionic liquid from the aqueous solution. In preferred embodiments, the method achieves an extraction efficiency of at least 80%, or a separation factor of at least 1.times.10.sup.4 when more than one radioisotope is included in the aqueous solution. In particular embodiments, the method is applied to the separation of medical isotopes pairs, such as Th from Ac (Th-229/Ac-225, Ac-227/Th-227), or Ra from Ac (Ac-225 and Ra-225, Ac-227 and Ra-223), or Ra from Th (Th-227 and Ra-223, Th-229 and Ra-225).

Intraocular levels of methotrexate after oral low-dose treatment in chronic uveitis.

PubMed

Puchta, Joachim; Hattenbach, Lars-Olof; Baatz, Holger

2005-01-01

To determine the intraocular levels of methotrexate in low-dose treatment of noninfectious uveitis. One day after oral administration, the methotrexate level was measured in the aqueous humor and serum of a patient with noninfectious uveitis, who underwent cataract surgery. A fluorescence polarization immunoassay was used for determination. After oral administration, methotrexate was only measurable in aqueous humor but not in serum. In uveitis, orally administered low-dose methotrexate reaches detectable levels in aqueous humor, even in the absence of detectable levels in serum. Copyright (c) 2005 S. Karger AG, Basel.

Apparatus for hydrocarbon extraction

DOEpatents

Bohnert, George W.; Verhulst, Galen G.

2013-03-19

Systems and methods for hydrocarbon extraction from hydrocarbon-containing material. Such systems and methods relate to extracting hydrocarbon from hydrocarbon-containing material employing a non-aqueous extractant. Additionally, such systems and methods relate to recovering and reusing non-aqueous extractant employed for extracting hydrocarbon from hydrocarbon-containing material.

EVALUATION OF TECHNOLOGIES FOR IN SITU CLEANUP OF DNAPL CONTAMINATED SITES

EPA Science Inventory

Ground water contamination by non-aqueous phase liquids poses one of the greatest remedial challenges in the field of environmental engineering. Denser-than-water non-aqueous phase liquids (DNAPLs) are especially problematic due to their low water solubility, high density, an...

Redox active polymers and colloidal particles for flow batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gavvalapalli, Nagarjuna; Moore, Jeffrey S.; Rodriguez-Lopez, Joaquin

The invention provides a redox flow battery comprising a microporous or nanoporous size-exclusion membrane, wherein one cell of the battery contains a redox-active polymer dissolved in the non-aqueous solvent or a redox-active colloidal particle dispersed in the non-aqueous solvent. The redox flow battery provides enhanced ionic conductivity across the electrolyte separator and reduced redox-active species crossover, thereby improving the performance and enabling widespread utilization. Redox active poly(vinylbenzyl ethylviologen) (RAPs) and redox active colloidal particles (RACs) were prepared and were found to be highly effective redox species. Controlled potential bulk electrolysis indicates that 94-99% of the nominal charge on different RAPsmore » is accessible and the electrolysis products are stable upon cycling. The high concentration attainable (>2.0 M) for RAPs in common non-aqueous battery solvents, their electrochemical and chemical reversibility, and their hindered transport across porous separators make them attractive materials for non-aqueous redox flow batteries based on size-selectivity.« less

Effect of Piper betle and Brucea javanica on the Differential Expression of Hyphal Wall Protein (HWP1) in Non-Candida albicans Candida (NCAC) Species

PubMed Central

Jamil, Nur Alyaa; Jamaludin, Nor Hazwani; Nordin, Mohd-Al-Faisal

2013-01-01

The study aimed to identify the HWP1 gene in non-Candida albicans Candida species and the differential expression of HWP1 following treatment with Piper betle and Brucea javanica aqueous extracts. All candidal suspensions were standardized to 1 × 106 cells/mL. The suspension was incubated overnight at 37 °C (C. parapsilosis, 35°C). Candidal cells were treated with each respective extract at 1, 3, and 6 mg/mL for 24 h. The total RNA was extracted and reverse transcription-polymerase chain reaction was carried out with a specific primer of HWP1. HWP1 mRNAs were only detected in C. albicans, C. parapsilosis, and C. tropicalis. Exposing the cells to the aqueous extracts has affected the expression of HWP1 transcripts. C. albicans, C. parapsilosis, and C. tropicalis have demonstrated different intensity of mRNA. Compared to P. betle, B. javanica demonstrated a higher suppression on the transcript levels of HWP1 in all samples. HWP1 was not detected in C. albicans following the treatment of B. javanica at 1 mg/mL. In contrast, C. parapsilosis and C. tropicalis were shown to have HWP1 regulation. However, the expression levels were reduced upon the addition of higher concentration of B. javanica extract. P. betle and B. javanica have potential to be developed as oral health product. PMID:23853657

Effect of Piper betle and Brucea javanica on the Differential Expression of Hyphal Wall Protein (HWP1) in Non-Candida albicans Candida (NCAC) Species.

PubMed

Wan Harun, Wan Himratul Aznita; Jamil, Nur Alyaa; Jamaludin, Nor Hazwani; Nordin, Mohd-Al-Faisal

2013-01-01

The study aimed to identify the HWP1 gene in non-Candida albicans Candida species and the differential expression of HWP1 following treatment with Piper betle and Brucea javanica aqueous extracts. All candidal suspensions were standardized to 1 × 10(6) cells/mL. The suspension was incubated overnight at 37 °C (C. parapsilosis, 35°C). Candidal cells were treated with each respective extract at 1, 3, and 6 mg/mL for 24 h. The total RNA was extracted and reverse transcription-polymerase chain reaction was carried out with a specific primer of HWP1. HWP1 mRNAs were only detected in C. albicans, C. parapsilosis, and C. tropicalis. Exposing the cells to the aqueous extracts has affected the expression of HWP1 transcripts. C. albicans, C. parapsilosis, and C. tropicalis have demonstrated different intensity of mRNA. Compared to P. betle, B. javanica demonstrated a higher suppression on the transcript levels of HWP1 in all samples. HWP1 was not detected in C. albicans following the treatment of B. javanica at 1 mg/mL. In contrast, C. parapsilosis and C. tropicalis were shown to have HWP1 regulation. However, the expression levels were reduced upon the addition of higher concentration of B. javanica extract. P. betle and B. javanica have potential to be developed as oral health product.

Evaluation of fast green FCF dye for non-lethal detection of integumental injuries in juvenile chinook salmon oncorhynchus tshawytscha

USGS Publications Warehouse

Elliott, D.G.; Conway, C.M.; Applegate, L.M.J.

2009-01-01

A rapid staining procedure for detection of recent skin and fin injuries was tested in juvenile Chinook salmon Oncorhynchus tshawytscha. Immersion of anesthetized fish for 1 min in aerated aqueous solutions of the synthetic food dye fast green FCF (Food Green 3) at concentrations of 0.1 to 0.5% produced consistent and visible staining of integumental injuries. A 0.1% fast green concentration was satisfactory for visual evaluation of injuries, whereas a 0.5% concentration was preferable for digital photography. A rinsing procedure comprised of two 30 s rinses in fresh water was most effective for removal of excess stain after exposure of fish. Survival studies in fresh water and seawater and histopathological analyses indicated that short exposures to aqueous solutions of fast green were non-toxic to juvenile Chinook salmon. In comparisons of the gross and microscopic appearance of fish exposed to fast green at various times after injury, the dye was observed only in areas of the body where epidermal disruption was present as determined by scanning electron microscopy. No dye was observed in areas where epidermal integrity had been restored. Further comparisons showed that fast green exposure produced more consistent and intense staining of skin injury sites than a previously published procedure using trypan blue. Because of its relatively low cost, ease of use and the rapid and specific staining of integumental injuries, fast green may find widespread application in fish health and surface injury evaluations. ?? Inter-Research 2009.

Negative Searches for Evidence of Aqueous Alteration on Asteroid Surfaces

NASA Technical Reports Server (NTRS)

Vilas, F.

2005-01-01

Small bodies in the Solar System preserve evidence of the processes occurring during early Solar System formation, unlike the larger planets that undergo continuous churning of their surfaces. We study these bodies to understand what processes affected different stages of Solar System formation. The action of aqueous alteration (the alteration of material by the interaction of that material with liquid formed by the melting of incorporated ice) of near-subsurface material has been inferred to occur on many asteroids based on the spectrophotometric evidence of phyllosilicates and iron alteration minerals. The definitive indication of aqueous alteration is the 3.0- micron absorption feature attributed to structural hydroxyl (OH) and interlayer and adsorbed water (H2O) in phyllosilicates (clays) (hereafter water of hydration). A weak absorption feature centered near 0.7 microns attributed to an Fe (2+) right arrow Fe (3+) charge transfer transition in oxidized iron in phyllosilicates has been observed in the reflectance spectra and photometry of approximately 50% of the main-belt C-class asteroids. An approximately 85% correlation between this 0.7- micron feature and the 3.0- micron water of hydration absorption feature was found among the low-albedo asteroids. The feature is usually centered near 0.68 microns in asteroid spectra, and ranges in wavelength from approximately 0.57 to 0.83 microns. Serendipitously, three of the Eight Color Asteroid Survey filters the v (0.550 microns), w (0.701 microns), and x (0.853 microns)-bracket this feature well, and can be used to determine the presence of this feature in the reflectance properties of an asteroid, and probe the aqueous alteration history of larger samples of asteroid data. Two efforts to search for evidence of aqueous alteration based on the presence of this 0.7- micron absorption feature are presented here.

Impact of different environmental conditions on the aggregation of biogenic U(IV) nanoparticles synthesized by Desulfovibrio alaskensis G20

DOE Office of Scientific and Technical Information (OSTI.GOV)

Şengör, S. Sevinç; Singh, Gursharan; Dohnalkova, Alice

This study investigates the impact of specific environmental conditions on the formation of colloidal U(IV) nanoparticles by the sulfate reducing bacteria (SRB, Desulfovibrio alaskensis G20). The reduction of soluble U(VI) to less soluble U(IV) was quantitatively investigated under growth and non-growth conditions in bicarbonate or 1,4-piperazinediethanesulfonic acid (PIPES) buffered environments. The results showed that under non-growth conditions, the majority of the reduced U nanoparticles aggregated and precipitated out of solution. High resolution transmission electron microscopy revealed that only a very small fraction of cells had reduced U precipitates in the periplasmic spaces in the presence of PIPES buffer, whereas inmore » the presence of bicarbonate buffer, reduced U was also observed in the cytoplasm with greater aggregation of biogenic U(IV) particles at higher initial U(VI) concentrations. The same experiments were repeated under growth conditions using two different electron donors (lactate and pyruvate) and three electron acceptors (sulfate, fumarate, and thiosulfate). In contrast to the results of the non-growth experiments, even after 0.2 m filtration, the majority of biogenic U(IV) remained in the aqueous phase resulting in potentially mobile biogenic U(IV) nanoparticles. Size fractionation results showed that U(IV) aggregates were between 18 and 200 nm in diameter, and thus could be very mobile. The findings of this study are helpful to assess the size and potential mobility of reduced U nanoparticles under different environmental conditions, and would provide insights on their potential impact affecting U(VI) bioremediation efforts at subsurface contaminated sites.« less

Effects of ethanol addition on micellar solubilization and plume migration during surfactant enhanced recovery of tetrachloroethene.

PubMed

Taylor, Tammy P; Rathfelder, Klaus M; Pennell, Kurt D; Abriola, Linda M

2004-03-01

Alcohol addition has been suggested for use in combination with surfactant flushing to enhance solubilization kinetics and permit density control of dense non-aqueous phase liquid (DNAPL)-laden surfactant plumes. This study examined the effects of adding ethanol (EtOH) to a 4% Tween 80 (polyoxyethylene (20) sorbitan monooleate) solution used to flush tetrachloroethene (PCE)-contaminated porous media. The influence of EtOH concentration, subsurface layering and scale on flushing solution delivery and PCE recovery was investigated through a combination of experimental and mathematical modeling studies. Results of batch experiments demonstrated that the addition of 2.5%, 5% and 10% (wt.) EtOH incrementally increased the PCE solubilization capacity and viscosity of the surfactant solution, while reducing solution density from 1.002 to 0.986 g/cm3. Effluent concentration data obtained from one-dimensional (1-D) column experiments were used to characterize rate-limited micellar solubilization of residual PCE, which was strongly dependent upon flow velocity and weakly dependent upon EtOH concentration. Two-dimensional (2-D) box studies illustrated that minor differences (0.008 g/cm3) between flushing and resident solution density can strongly influence surfactant front propagation. A two-dimensional multiphase simulator, MISER, was used to model the influence of EtOH composition on the aqueous flow field and PCE mass recovery. The ability of the numerical simulator to predict effluent concentrations and front propagation was demonstrated for both 1-D columns and 2-D boxes flushed with EtOH-amended Tween 80 solutions. Results of this study quantify the potential influence of alcohol addition on surfactant solution properties and solubilization capacity, and demonstrate the importance of considering small density variations in remedial design.

A compilation of rate parameters of water-mineral interaction kinetics for application to geochemical modeling

USGS Publications Warehouse

Palandri, James L.; Kharaka, Yousif K.

2004-01-01

Geochemical reaction path modeling is useful for rapidly assessing the extent of water-aqueous-gas interactions both in natural systems and in industrial processes. Modeling of some systems, such as those at low temperature with relatively high hydrologic flow rates, or those perturbed by the subsurface injection of industrial waste such as CO2 or H2S, must account for the relatively slow kinetics of mineral-gas-water interactions. We have therefore compiled parameters conforming to a general Arrhenius-type rate equation, for over 70 minerals, including phases from all the major classes of silicates, most carbonates, and many other non-silicates. The compiled dissolution rate constants range from -0.21 log moles m-2 s-1 for halite, to -17.44 log moles m-2 s-1 for kyanite, for conditions far from equilibrium, at 25 ?C, and pH near neutral. These data have been added to a computer code that simulates an infinitely well-stirred batch reactor, allowing computation of mass transfer as a function of time. Actual equilibration rates are expected to be much slower than those predicted by the selected computer code, primarily because actual geochemical processes commonly involve flow through porous or fractured media, wherein the development of concentration gradients in the aqueous phase near mineral surfaces, which results in decreased absolute chemical affinity and slower reaction rates. Further differences between observed and computed reaction rates may occur because of variables beyond the scope of most geochemical simulators, such as variation in grain size, aquifer heterogeneity, preferred fluid flow paths, primary and secondary mineral coatings, and secondary minerals that may lead to decreased porosity and clogged pore throats.

User’s guide to the collection and analysis of tree cores to assess the distribution of subsurface volatile organic compounds

USGS Publications Warehouse

Vroblesky, Don A.

2008-01-01

Analysis of the volatile organic compound content of tree cores is an inexpensive, rapid, simple approach to examining the distribution of subsurface volatile organic compound contaminants. The method has been shown to detect several volatile petroleum hydrocarbons and chlorinated aliphatic compounds associated with vapor intrusion and ground-water contamination. Tree cores, which are approximately 3 inches long, are obtained by using an increment borer. The cores are placed in vials and sealed. After a period of equilibration, the cores can be analyzed by headspace analysis gas chromatography. Because the roots are exposed to volatile organic compound contamination in the unsaturated zone or shallow ground water, the volatile organic compound concentrations in the tree cores are an indication of the presence of subsurface volatile organic compound contamination. Thus, tree coring can be used to detect and map subsurface volatile organic compound contamination. For comparison of tree-core data at a particular site, it is important to maintain consistent methods for all aspects of tree-core collection, handling, and analysis. Factors affecting the volatile organic compound concentrations in tree cores include the type of volatile organic compound, the tree species, the rooting depth, ground-water chemistry, the depth to the contaminated horizon, concentration differences around the trunk related to variations in the distribution of subsurface volatile organic compounds, concentration differences with depth of coring related to volatilization loss through the bark and possibly other unknown factors, dilution by rain, seasonal influences, sorption, vapor-exchange rates, and within-tree volatile organic compound degradation.

Nanomolar detection of hypochlorite by a rhodamine-based chiral hydrazide in absolute aqueous media: application in tap water analysis with live-cell imaging.

PubMed

Goswami, Shyamaprosad; Das, Avijit Kumar; Manna, Abhishek; Maity, Anup Kumar; Saha, Partha; Quah, Ching Kheng; Fun, Hoong-Kun; Abdel-Aziz, Hatem A

2014-07-01

By employing the oxidation property of hypochlorite (OCl(-)), a novel rhodamine-based hydrazide of the chiral acid ((S)-(-)-2-pyrrolidone-5-carboxylic acid) (RHHP) was designed and synthesized for detection of OCl(-) absolutely in aqueous medium at nanomolar level. The structure of the chiral sensor was also proved by the X-ray crystallography. The bioactivity and the application of the probe for detection of OCl(-) in natural water system have been demonstrated. A plausible mechanism for oxidation of the sensor followed by hydrolysis is also proposed. The sensibility of the receptor toward OCl(-) was studied in absolute aqueous media, and the detection limit of hypochlorite-mediated oxidation to the receptor in nanomolar level makes this platform (RHHP) an ultrasensitive and unique system for OCl(-) oxidation.

Magnetic signature of Siaolin Village, southern Taiwan, after burial by a catastrophic landslide due to Typhoon Morakot

NASA Astrophysics Data System (ADS)

Doo, W.-B.; Hsu, S.-K.; Chen, C.-C.; Hsieh, H.-H.; Yen, H.-Y.; Chen, Y.-G.; Chang, W.-Y.

2011-03-01

Typhoon Morakot caused terrible flooding and torrential rains that severely damaged southern Taiwan. Swollen rivers wiped out roads and demolished buildings. Long-lasting and intense rainfall triggered landslides in many regions in southern Taiwan, including the landslide that buried Siaolin Village in Kaohsiung County and killed approximately 500 people. Locating buried buildings immediately after a landslide could be an emergent issue in life saving and hazard mitigation. Analyzing the magnetic signature of a buried area is an efficient and non-destructive way to detect subsurface buildings. This paper presents the results of a magnetic survey for the purpose of outlining subsurface images of Siaolin Village after the catastrophic landslide induced by Typhoon Morakot in 2009. We found that a high-resolution magnetic survey can reveal suspected building positions that match the initial locations of buildings in Siaolin Village. The estimated depths of the buried buildings are 5-10 m deep. The magnetic data further suggest a possible debris-flow direction of NE to SW because the northern part of the village was mostly destroyed, while buildings in the southern part of the village remained in place.

On the characterization of subsurface flow and hydraulic conductivity from surface SP measurements: correcting for electrical heterogeneities.

NASA Astrophysics Data System (ADS)

Sailhac, P.; Marquis, G.; Darnet, M.; Szalai, S.

2003-04-01

Surface self potential measurements (SP) are useful to characterize underground fluid flow or chemical reactions (as redox) and can be used in addition to NMR and electrical prospecting in hydrological investigations. Assuming that the SP anomalies have an electrokinetic origin, the source of SP data is the divergence of underground fluid flow; one important problem with surface SP data is then its interpretation in terms of fluid flow geometry. Some integral transform techniques have been shown to be powerful for SP interpretation (e.g. Fournier 1989, Patella, 1997; Sailhac &Marquis 2001). All these techniques are based upon Green’{ }s functions to characterize underground water flow, but they assume a constant electrical conductivity in the subsurface. This unrealistic approximation results in the appearance of non-electrokinetic sources at strong lateral electrical conductivity contrasts. We present here new Green’{ }s functions suitable for media of heterogeneous electrical conductivity. This new approach allows the joint interpretation of electrical resistivity tomography and SP measurements to detect electrokinetic sources caused by fluid flow. Tests on synthetic examples show that it gives more realistic results that when a constant electrical conductivity is assumed.

Site Selection for Mars Exopaleontology in 2001

NASA Technical Reports Server (NTRS)

Farmer, Jack

1998-01-01

The microbial fossil record encompasses a wide range of information, including cellular remains, stromatolites, biofabrics, trace fossils, biominerals and chemofossils. The preservation of fossils is strongly influenced by the physical, chemical and biological factors of the environment which, acting together, ultimately determine the types of information that will be captured and retained in the rock record. The critical factor in assessing the suitability of a site for a microbial fossil record is the paleoenvironment. The reconstruction of ancient sedimentary environments usually requires the integration of a wide variety of geological information, including the shape, geometry and internal structure of sedimentary deposits, their mineralogy, and geochemistry. For Mars, much of our knowledge about past environments is based on orbital imaging of geomorphic features. This evidence provides an important context and starting point for site selection. However, our knowledge of the martian surface is quite limited, and a major goal of the upcoming exploration effort is to reconstruct the history of Martian volatiles, climate, and hydrology as a context for the exploration for past or present life. Mineralogical mapping from orbit will be an important key in this effort. In exploring for evidence of past life, terrestrial experience suggests that the long-term preservation of biological information as fossils occurs under a fairly narrow range of geological conditions that are well known to paleontologists (1). In detrital sedimentary systems, microbial fossilization is favored by rapid burial in fine-grained, clay-rich sediments. In chemical sedimentary systems, preservation is enhanced by rapid entombment in fine-grained chemical precipitates. For long term preservation, host rocks must be composed of stable minerals that resist chemical weathering, and which form an impermeable matrix and closed chemical system that can protect biosignatures from alteration during subsequent diagenetic change or metamorphism. In this context, host rocks composed of highly ordered, chemically-stable mineral phases, like silica (forming cherts) or phosphate (forming phosphorites), are especially favored. Such lithologies tend to have very long crustal residence times and (along with carbonates and shales), are the most common host rocks for the Precambrian microfossil record on Earth. If we assume that a subsurface hydrosphere has been present throughout martian history, then life could have originated there at any time, perhaps emerging at the surface periodically when climate changes, induced by external forcing or endogenous processes (e.g. volcanism), allowed liquid water to exist at the surface. The recent discovery of subsurface chemolithoautotrophic organisms which are capable of synthesizing organic substrates from C02 and H2 liberated from the aqueous weathering of basalt, is especially. relevant as a model for martian life. While a subsurface habitable zone may yet exist on Mars, access to such environments will likely require drilling to depths of several kilometers. Given the technological challenge of deep drilling, this is unlikely to occur prior to human missions. So, even if there is extant life on Mars today in subsurface habitats, it may be much easier to find its fossil counterparts in ancient deposits exposed at the surface. In exploring for a fossil record in subsurface environments on Mars there are several geological situations that may provide access to the appropriate materials. These include 1) ejecta from impact craters, 2) talus slopes, debris flows or alluvial fans developed below the walls of deep canyons, and 3) the deposits of outflood channels. Examples of aqueous mineral deposits of formed in subsurface environments that could harbor a microbial fossil record include such things as cements in detrital sedimentary rocks, low temperature diagenetic minerals deposited in veins, or filling vesicles in volcanic rocks, and hydrothermal deposits formed below the upper temperature limit for life (about 160 degrees C). There are many sites within the present latitudinal constraints for the 2001 mission (15 deg S to 30 deg N) that meet these requirements. But the practical problem with these kinds of deposits is that they tend to be disseminated, making up only a small percentage of a host rock. Even with mineralogical information provided by the Thermal Emission Spectrometer (TES) presently in orbit around Mars, predicting their occurrence ahead of time may be quite difficult. The deposits of surficial aqueous sedimentary systems are likely to provide the largest targets for site selection in 2001. Of these, the deposits of hydrothermal systems (subaerial and subaqueous thermal springs) have been discussed previously. It is likely that hydrothermal systems were widespread on Mars early in its history and a number of common geo-tectonic settings on Mars are likely to have hosted hydrothermal activity. Most of these are represented within the latitudinal constraints presently identified for 2001. However, the deposits of surface spring systems are likely to be difficult to find as well. On Earth, exposure areas for hydrothermal spring mounds are typically a few square kms, less than a single TES pixel. But such deposits may be quite abundant within some volcanic terrains, It is estimated, for example, that between 15-20% of the floor of Yellowstone caldera is covered by thermal spring deposits. In such abundances, subaerial sinters could well be detected by TES. Where exposed, the shallow subsurface portions of these systems may be quite a lot larger (perhaps tens of square kms), although (as noted above) mineralization may be finely disseminated in the basement rock, making remote detection more difficult. Paleolake Basins. There are a large number of potential paleolake basins on Mars (inclusive of impact craters and volcanic calderas) that have been previously identified using Viking images. Most of these lie in the southern highlands beyond the l5 deg S constraint for 2001. However, deposits of paleolakes may offer the largest and most easily identified exopaleontological targets from orbit. Based on a variety of arguments, some workers have suggested that there was once an ancient ocean on the northern plains, and some sites of interest (potential shoreline terraces) fall within the 30 deg N constraint. From a paleontological standpoint the most interesting places of this type are terminal paleolake basins which are likely to have been both saline and alkaline. Models by Schaefer suggest such environments could be widespread on Mars. The conditions in terminal lake basin settings favor widespread chemical sedimentation, an important condition for microbial fossilization. Important lithological targets for a microbial fossil record in terminal lake basins include spring-deposited carbonates, shoreline cements, a wide variety of evaporite minerals and fine-grained detrital sediments including shales, marls, and water-lain volcanic ash deposits. In developing a strategy to explore for ancient hydrothermal deposits on Mars, we can learn from the methods that have been developed by explorationists to explore for economic mineral deposits on Earth. Due to their simple mineralogy, hydrothermal deposits can often be detected using remote sensing methods. Common thermal spring mineral assemblages include silica, carbonate, and various metallic oxides and sulfides. But there are also a number of diagnostic silicate minerals, including clays, formed by the hydrothermal alteration of country rocks. These hydrothermal minerals have characteristic spectral signatures that could be detected from Mars orbit using high resolution infrared remote sensing methods. In playa lake settings, evaporite deposits often form a predictable "bull's eye" pattern with carbonates being deposited in marginal basin areas, and sulfates and halides occurring progressively mo re basinward. The floors of some impact craters on Mars, such as "White Rock" and Bequeral Crater (see Oxia Palus NE, Site 148), have floor deposits that could be evaporites, inclusive of carbonates. Evaporite minerals possess characteristic spectral signatures in the infrared and could similarly be identified from Mars orbit using high resolution remote sensing methods. Clearly, utilization of TES data will be important for optimizing site selection for Exopaleontology, and every effort should be made to benefit from that data before a final decision is made.

Apparatus and methods for hydrocarbon extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bohnert, George W.; Verhulst, Galen G.

Systems and methods for hydrocarbon extraction from hydrocarbon-containing material. Such systems and methods relate to extracting hydrocarbon from hydrocarbon-containing material employing a non-aqueous extractant. Additionally, such systems and methods relate to recovering and reusing non-aqueous extractant employed for extracting hydrocarbon from hydrocarbon-containing material.

Interpretation of Data from Uphole Refraction Surveys

DTIC Science & Technology

1980-06-01

Seismic refraction Seismic refraction method Seismic surveys Subsurface exploration ""-. 20, AI0SrRACT -(CmtuamU 00MvaO eL If naaaaamr and Identlfyby...by the presence of subsurface cavities and large cavities are identifiable, the sensitivity of the method is marginal for practical use in cavity...detection. Some cavities large enough to be of engineering signifi- cance (e.g., a tunnel of h-m diameter) may be practically undetectable by this method

Improving sensitivity and specificity of capturing and detecting targeted cancer cells with anti-biofouling polymer coated magnetic iron oxide nanoparticles.

PubMed

Lin, Run; Li, Yuancheng; MacDonald, Tobey; Wu, Hui; Provenzale, James; Peng, Xingui; Huang, Jing; Wang, Liya; Wang, Andrew Y; Yang, Jianyong; Mao, Hui

2017-02-01

Detecting circulating tumor cells (CTCs) with high sensitivity and specificity is critical to management of metastatic cancers. Although immuno-magnetic technology for in vitro detection of CTCs has shown promising potential for clinical applications, the biofouling effect, i.e., non-specific adhesion of biomolecules and non-cancerous cells in complex biological samples to the surface of a device/probe, can reduce the sensitivity and specificity of cell detection. Reported herein is the application of anti-biofouling polyethylene glycol-block-allyl glycidyl ether copolymer (PEG-b-AGE) coated iron oxide nanoparticles (IONPs) to improve the separation of targeted tumor cells from aqueous phase in an external magnetic field. PEG-b-AGE coated IONPs conjugated with transferrin (Tf) exhibited significant anti-biofouling properties against non-specific protein adsorption and off-target cell uptake, thus substantially enhancing the ability to target and separate transferrin receptor (TfR) over-expressed D556 medulloblastoma cells. Tf conjugated PEG-b-AGE coated IONPs exhibited a high capture rate of targeted tumor cells (D556 medulloblastoma cell) in cell media (58.7±6.4%) when separating 100 targeted tumor cells from 1×10 5 non-targeted cells and 41 targeted tumor cells from 100 D556 medulloblastoma cells spiked into 1mL blood. It is demonstrated that developed nanoparticle has higher efficiency in capturing targeted cells than widely used micron-sized particles (i.e., Dynabeads ® ). Copyright © 2016 Elsevier B.V. All rights reserved.

Infrared emission contrast for the visualization of subsurface graphical features in artworks

NASA Astrophysics Data System (ADS)

Mercuri, Fulvio; Paoloni, Stefano; Cicero, Cristina; Zammit, Ugo; Orazi, Noemi

2018-03-01

In this paper a method is presented based on the use of active infrared thermography for the detection of subsurface graphical features in artworks. A theoretical model for the thermographic signal describing the physical mechanisms which allow the identification of the buried features has been proposed and thereafter it has been applied to the analysis of the results obtained on specifically made test samples. It is shown that the proposed model predictions adequately describe the experimental results obtained on the test samples. A comparative analysis between the proposed technique and infrared reflectography is also presented. The comparison shows that active thermography can be more effective in the detection of features buried below infrared translucent layers and, in addition, that it can provide information about the depth of the detected features, particularly in highly IR diffusing materials.

Soil and Water Pollution in a Banana Production Region in Tropical Mexico

PubMed Central

Ramos, Franzisco Que; de J. Bastidas-Bastidas, Pedro; Díaz-González, Gilberto; Bello-Mendoza, Ricardo; Huerta-Lwanga, Esperanza; Ruiz-Suárez, Luz E.

2010-01-01

The effects of abundant Mancozeb (Mn, Zn—bisdithiocarbamate) applications (2.5 kg ha−1week−1 for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the main metabolite ethylenethiourea was near the detection limit. Surface and subsurface water was highly polluted with ethylenethiourea, the main metabolite of Mancozeb (22.5 and 4.3 μg L−1, respectively), but not with manganese. In deep ground water, no ethylenethiourea was detected. The level of pollution in the region presents a worrisome risk for aquatic life and for human health. PMID:20734023

Soil and water pollution in a banana production region in tropical Mexico.

PubMed

Geissen, Violette; Ramos, Franzisco Que; de J Bastidas-Bastidas, Pedro; Díaz-González, Gilberto; Bello-Mendoza, Ricardo; Huerta-Lwanga, Esperanza; Ruiz-Suárez, Luz E

2010-10-01

The effects of abundant Mancozeb (Mn, Zn-bisdithiocarbamate) applications (2.5 kg ha⁻¹week⁻¹ for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the main metabolite ethylenethiourea was near the detection limit. Surface and subsurface water was highly polluted with ethylenethiourea, the main metabolite of Mancozeb (22.5 and 4.3 μg L⁻¹, respectively), but not with manganese. In deep ground water, no ethylenethiourea was detected. The level of pollution in the region presents a worrisome risk for aquatic life and for human health.

Synthesis of a mixed-model stationary phase derived from glutamine for HPLC separation of structurally different biologically active compounds: HILIC and reversed-phase applications.

PubMed

Aral, Tarık; Aral, Hayriye; Ziyadanoğulları, Berrin; Ziyadanoğulları, Recep

2015-01-01

A novel mixed-mode stationary phase was synthesised starting from N-Boc-glutamine, aniline and spherical silica gel (4 µm, 60 Å). The prepared stationary phase was characterized by IR and elemental analysis. The new stationary phase bears an embedded amide group into phenyl ring, highly polar a terminal amide group and non-polar groups (phenyl and alkyl groups). At first, this new mixed-mode stationary phase was used for HILIC separation of four nucleotides and five nucleosides. The effects of different separation conditions, such as pH value, mobile phase and temperature, on the separation process were investigated. The optimum separation for nucleotides was achieved using HILIC isocratic elution with aqueous mobile phase and acetonitrile with 20°C column temperature. Under these conditions, the four nucleotides could be separated and detected at 265 nm within 14 min. Five nucleosides were separated under HILIC isocratic elution with aqueous mobile phase containing pH=3.25 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 265 nm within 14 min. Chromatographic parameters as retention factor, selectivity, theoretical plate number and peak asymmetry factor were calculated for the effect of temperature and water content in mobile phase on the separation process. The new column was also tested for nucleotides and nucleosides mixture and six analytes were separated in 10min. The chromatographic behaviours of these polar analytes on the new mixed-model stationary phase were compared with those of HILIC columns under similar conditions. Further, phytohormones and phenolic compounds were separated in order to see influence of the new stationary phase in reverse phase conditions. Eleven plant phytohormones were separated within 13 min using RP-HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 230 or 278 nm. The best separation conditions for seven phenolic compounds was also achieved using reversed-phase HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and seven phenolic compounds could be separated and detected at 230 nm within 16 min. Copyright © 2014 Elsevier B.V. All rights reserved.

Nondestructive evaluation of structural ceramics by photoacoustic microscopy

NASA Technical Reports Server (NTRS)

Khandelwal, Pramod K.

1987-01-01

A photoacoustic microscopy (PAM) digital imaging system was developed and utilized to characterize silicon nitride material at the various stages of the ceramic fabrication process. Correlation studies revealed that photoacoustic microscopy detected failure initiating defects in substantially more specimens than microradiography and ultrasonic techniques. Photoacoustic microscopy detected 10 to 100 micron size surface and subsurface pores and inclusions, respectively, up to 80 microns below the interrogating surface in machined sintered silicon nitride. Microradiography detected 50 micron diameter fracture controlling pores and inclusions. Subsurface holes were detected up to a depth of 570 microns and 1.00 mm in sintered silicon nitride and silicon carbide, respectively. Seeded voids of 20 to 30 micron diameters at the surface and 50 microns below the interrogating surface were detected by photoacoustic microscopy and microradiography with 1 percent X-ray thickness sensitivity. Tight surface cracks of 96 micron length x 48 micron depth were detected by photoacoustic microscopy. PAM volatilized and removed material in the green state which resulted in linear shallow microcracks after sintering. This significantly limits the use of PAM as an in-process NDE technique.

Electrical Resistivity Tomography and Ground Penetrating Radar for locating buried petrified wood sites: a case study in the natural monument of the Petrified Forest of Evros, Greece

NASA Astrophysics Data System (ADS)

Vargemezis, George; Diamanti, Nectaria; Tsourlos, Panagiotis; Fikos, Ilias

2014-05-01

A geophysical survey was carried out in the Petrified Forest of Evros, the northernmost regional unit of Greece. This collection of petrified wood has an age of approximately 35 million years and it is the oldest in Greece (i.e., older than the well-known Petrified Forest of Lesvos island located in the North Aegean Sea and which is possibly the largest of the petrified forests worldwide). Protection, development and maintenance projects still need to be carried out at the area despite all fears regarding the forest's fate since many petrified logs remain exposed both in weather conditions - leading to erosion - and to the public. This survey was conducted as part of a more extensive framework regarding the development and protection of this natural monument. Geophysical surveying has been chosen as a non-destructive investigation method since the area of application is both a natural ecosystem and part of cultural heritage. Along with electrical resistivity tomography (ERT), ground penetrating radar (GPR) surveys have been carried out for investigating possible locations of buried fossilized tree trunks. The geoelectrical sections derived from ERT data in combination with the GPR profiles provided a broad view of the subsurface. Two and three dimensional subsurface geophysical images of the surveyed area have been constructed, pointing out probable locations of petrified logs. Regarding ERT, petrified trunks have been detected as high resistive bodies, while lower resistivity values were more related to the surrounding geological materials. GPR surveying has also indicated buried petrified log locations. As these two geophysical methods are affected in different ways by the subsurface conditions, the combined use of both techniques enhanced our ability to produce more reliable interpretations of the subsurface. After the completion of the geophysical investigations of this first stage, petrified trunks were revealed after a subsequent excavation at indicated locations. Moreover, we identified possible buried petrified targets at locations yet to be excavated.

Element mobilization and immobilization from carbonate rocks between CO2 storage reservoirs and the overlying aquifers during a potential CO2 leakage.

PubMed

Lawter, Amanda R; Qafoku, Nikolla P; Asmussen, R Matthew; Kukkadapu, Ravi K; Qafoku, Odeta; Bacon, Diana H; Brown, Christopher F

2018-04-01

Despite the numerous studies on changes within the reservoir following CO 2 injection and the effects of CO 2 release into overlying aquifers, little or no literature is available on the effect of CO 2 release on rock between the storage reservoirs and subsurface. This is important, because the interactions that occur in this zone between the CO 2 storage reservoir and the subsurface may have a significant impact on risk analysis for CO 2 storage projects. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in this intermediate zone. After rocks reacted with CO 2 -acidified 0.01 M NaCl, liquid analysis showed an increase of major elements (e.g., Ca and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower aqueous concentrations of these elements were observed in N 2 control experiments, likely due to differences in pH between the CO 2 and N 2 experiments. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO 2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO 2 -reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO 2 -laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Element mobilization and immobilization from carbonate rocks between CO 2 storage reservoirs and the overlying aquifers during a potential CO 2 leakage

DOE PAGES

Lawter, Amanda R.; Qafoku, Nikolla P.; Asmussen, R. Matthew; ...

2018-01-04

In spite of the numerous studies on changes within the reservoir following CO 2 injection and the effects of CO 2 release into overlying aquifers, little or no literature is available on the effect of CO 2 release on rock between the storage reservoirs and subsurface. This is important, because the interactions that occur in this zone between the CO 2 storage reservoir and the subsurface may have a significant impact on risk analysis for CO 2 storage projects. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in thismore » intermediate zone. Furthermore, after rocks reacted with CO 2-acidified 0.01 M NaCl, liquid analysis showed an increase of major elements (e.g., Ca and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower aqueous concentrations of these elements were observed in N 2 control experiments, likely due to differences in pH between the CO 2 and N 2 experiments. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO 2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO 2-reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO 2-laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation.« less

Intermediate-Scale Experimental Study to Improve Fundamental Understanding of Attenuation Capacity for Leaking CO2 in Heterogeneous Shallow Aquifers

NASA Astrophysics Data System (ADS)

Plampin, Michael R.; Porter, Mark L.; Pawar, Rajesh J.; Illangasekare, Tissa H.

2017-12-01

To assess the risks of Geologic Carbon Sequestration (GCS), it is crucial to understand the fundamental physicochemical processes that may occur if and when stored CO2 leaks upward from a deep storage reservoir into the shallow subsurface. Intermediate-scale experiments allow for improved understanding of the multiphase evolution processes that control CO2 migration behavior in the subsurface, because the boundary conditions, initial conditions, and porous media parameters can be better controlled and monitored in the laboratory than in field settings. For this study, a large experimental test bed was designed to mimic a cross section of a shallow aquifer with layered geologic heterogeneity. As water with aqueous CO2 was injected into the system to mimic a CO2-charged water leakage scenario, the spatiotemporal evolution of the multiphase CO2 plume was monitored. Similar experiments were performed with two different sand combinations to assess the relative effects of different types of geologic facies transitions on the CO2 evolution processes. Significant CO2 attenuation was observed in both scenarios, but by fundamentally different mechanisms. When the porous media layers had very different permeabilities, attenuation was caused by local accumulation (structural trapping) and slow redissolution of gas phase CO2. When the permeability difference between the layers was relatively small, on the other hand, gas phase continually evolved over widespread areas near the leading edge of the aqueous plume, which also attenuated CO2 migration. This improved process understanding will aid in the development of models that could be used for effective risk assessment and monitoring programs for GCS projects.

Intermediate-Scale Experimental Study to Improve Fundamental Understanding of Attenuation Capacity for Leaking CO 2 in Heterogeneous Shallow Aquifers

DOE PAGES

Plampin, Michael R.; Porter, Mark L.; Pawar, Rajesh J.; ...

2017-11-15

In order to assess the risks of Geologic Carbon Sequestration (GCS), it is crucial to understand the fundamental physicochemical processes that may occur if and when stored CO 2 leaks upward from a deep storage reservoir into the shallow subsurface. Intermediate-scale experiments allow for improved understanding of the multiphase evolution processes that control CO 2 migration behaviour in the subsurface, because the boundary conditions, initial conditions, and porous media parameters can be better controlled and monitored in the laboratory than in field settings. For this study, a large experimental test bed was designed to mimic a cross-section of a shallowmore » aquifer with layered geologic heterogeneity. As water with aqueous CO 2 was injected into the system to mimic a CO 2-charged water leakage scenario, the spatiotemporal evolution of the multiphase CO 2 plume was monitored. Similar experiments were performed with two different sand combinations to assess the relative effects of different types of geologic facies transitions on the CO 2 evolution processes. Significant CO 2 attenuation was observed in both scenarios, but by fundamentally different mechanisms. When the porous media layers had very different permeabilities, attenuation was caused by local accumulation (structural trapping) and slow re-dissolution of gas phase CO 2. When the permeability difference between the layers was relatively small, on the other hand, gas phase continually evolved over widespread areas near the leading edge of the aqueous plume, which also attenuated CO 2 migration. In conclusion, this improved process understanding will aid in the development of models that could be used for effective risk assessment and monitoring programs for GCS projects.« less

Intermediate-Scale Experimental Study to Improve Fundamental Understanding of Attenuation Capacity for Leaking CO 2 in Heterogeneous Shallow Aquifers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plampin, Michael R.; Porter, Mark L.; Pawar, Rajesh J.

In order to assess the risks of Geologic Carbon Sequestration (GCS), it is crucial to understand the fundamental physicochemical processes that may occur if and when stored CO 2 leaks upward from a deep storage reservoir into the shallow subsurface. Intermediate-scale experiments allow for improved understanding of the multiphase evolution processes that control CO 2 migration behaviour in the subsurface, because the boundary conditions, initial conditions, and porous media parameters can be better controlled and monitored in the laboratory than in field settings. For this study, a large experimental test bed was designed to mimic a cross-section of a shallowmore » aquifer with layered geologic heterogeneity. As water with aqueous CO 2 was injected into the system to mimic a CO 2-charged water leakage scenario, the spatiotemporal evolution of the multiphase CO 2 plume was monitored. Similar experiments were performed with two different sand combinations to assess the relative effects of different types of geologic facies transitions on the CO 2 evolution processes. Significant CO 2 attenuation was observed in both scenarios, but by fundamentally different mechanisms. When the porous media layers had very different permeabilities, attenuation was caused by local accumulation (structural trapping) and slow re-dissolution of gas phase CO 2. When the permeability difference between the layers was relatively small, on the other hand, gas phase continually evolved over widespread areas near the leading edge of the aqueous plume, which also attenuated CO 2 migration. In conclusion, this improved process understanding will aid in the development of models that could be used for effective risk assessment and monitoring programs for GCS projects.« less

Element mobilization and immobilization from carbonate rocks between CO 2 storage reservoirs and the overlying aquifers during a potential CO 2 leakage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawter, Amanda R.; Qafoku, Nikolla P.; Asmussen, R. Matthew

In spite of the numerous studies on changes within the reservoir following CO 2 injection and the effects of CO 2 release into overlying aquifers, little or no literature is available on the effect of CO 2 release on rock between the storage reservoirs and subsurface. This is important, because the interactions that occur in this zone between the CO 2 storage reservoir and the subsurface may have a significant impact on risk analysis for CO 2 storage projects. To address this knowledge gap, relevant rock materials, temperatures and pressures were used to study mineralogical and elemental changes in thismore » intermediate zone. Furthermore, after rocks reacted with CO 2-acidified 0.01 M NaCl, liquid analysis showed an increase of major elements (e.g., Ca and Mg) and variable concentrations of potential contaminants (e.g., Sr and Ba); lower aqueous concentrations of these elements were observed in N 2 control experiments, likely due to differences in pH between the CO 2 and N 2 experiments. In experiments with As/Cd and/or organic spikes, representing potential contaminants in the CO 2 plume originating in the storage reservoir, most or all of these contaminants were removed from the aqueous phase. SEM and Mössbauer spectroscopy results showed the formation of new minerals and Fe oxides in some CO 2-reacted samples, indicating potential for contaminant removal through mineral incorporation or adsorption onto Fe oxides. These experiments show the interactions between the CO 2-laden plume and the rock between storage reservoirs and overlying aquifers have the potential to affect the level of risk to overlying groundwater, and should be considered during site selection and risk evaluation.« less

A Stability-Indicating HPLC Method for the Determination of Nitrosylcobalamin (NO-Cbl), a Novel Vitamin B12 Analog.

PubMed

Dunphy, Michael J; Sysel, Annette M; Lupica, Joseph A; Griffith, Kristie; Sherrod, Taylor; Bauer, Joseph A

2014-04-01

Nitrosylcobalamin (NO-Cbl), a novel vitamin B 12 analog and anti-tumor agent, functions as a biologic 'Trojan horse', utilizing the vitamin B 12 transcobalamin II transport protein and cell surface receptor to specifically target cancer cells. a stability-indicating HPLC method was developed for the detection of NO-Cbl during forced degradation studies. This method utilized an ascentis ® RP-amide (150 mm × 4.6 mm, 5 μm) column at 35 °C with a mobile phase (1.0 mL min -1 ) combining a gradient of methanol and an acetate buffer at pH 6.0. Detection wavelengths of 450 and 254 nm were used to detect corrin and non-corrin-based products, respectively. NO-Cbl, synthesized from hydroxocobalamin and pure nitric oxide gas, was subjected to degradative stress conditions including oxidation, hydrolysis and thermal and radiant energy challenge. The method was validated by assessing linearity, accuracy, precision, detection and quantitation limits and robustness. The method was applied successfully for purity assessment of synthesized NO-Cbl and for the determination of NO-Cbl during kinetic studies in aqueous solution and in solid-state degradation assessments. This HPLC method is suitable for the separation of cobalamins in aqueous and methanolic solutions, for routine detection of NO-Cbl and for purity assessment of synthesized NO-Cbl. additionally, this method has potential application in identification and monitoring of diseases involving altered nitric oxide homeostasis where vitamin B 12 therapy is utilized to scavenge excess nitric oxide, subsequently resulting in the in vivo production of NO-Cbl.

A Stability-Indicating HPLC Method for the Determination of Nitrosylcobalamin (NO-Cbl), a Novel Vitamin B12 Analog

PubMed Central

Dunphy, Michael J.; Sysel, Annette M.; Lupica, Joseph A.; Griffith, Kristie; Sherrod, Taylor

2014-01-01

Nitrosylcobalamin (NO-Cbl), a novel vitamin B12 analog and anti-tumor agent, functions as a biologic ‘Trojan horse’, utilizing the vitamin B12 transcobalamin II transport protein and cell surface receptor to specifically target cancer cells. a stability-indicating HPLC method was developed for the detection of NO-Cbl during forced degradation studies. This method utilized an ascentis® RP-amide (150 mm × 4.6 mm, 5 μm) column at 35 °C with a mobile phase (1.0 mL min−1) combining a gradient of methanol and an acetate buffer at pH 6.0. Detection wavelengths of 450 and 254 nm were used to detect corrin and non-corrin-based products, respectively. NO-Cbl, synthesized from hydroxocobalamin and pure nitric oxide gas, was subjected to degradative stress conditions including oxidation, hydrolysis and thermal and radiant energy challenge. The method was validated by assessing linearity, accuracy, precision, detection and quantitation limits and robustness. The method was applied successfully for purity assessment of synthesized NO-Cbl and for the determination of NO-Cbl during kinetic studies in aqueous solution and in solid-state degradation assessments. This HPLC method is suitable for the separation of cobalamins in aqueous and methanolic solutions, for routine detection of NO-Cbl and for purity assessment of synthesized NO-Cbl. additionally, this method has potential application in identification and monitoring of diseases involving altered nitric oxide homeostasis where vitamin B12 therapy is utilized to scavenge excess nitric oxide, subsequently resulting in the in vivo production of NO-Cbl. PMID:24855323

Surface and subsurface cracks characteristics of single crystal SiC wafer in surface machining

NASA Astrophysics Data System (ADS)

Qiusheng, Y.; Senkai, C.; Jisheng, P.

2015-03-01

Different machining processes were used in the single crystal SiC wafer machining. SEM was used to observe the surface morphology and a cross-sectional cleavages microscopy method was used for subsurface cracks detection. Surface and subsurface cracks characteristics of single crystal SiC wafer in abrasive machining were analysed. The results show that the surface and subsurface cracks system of single crystal SiC wafer in abrasive machining including radial crack, lateral crack and the median crack. In lapping process, material removal is dominated by brittle removal. Lots of chipping pits were found on the lapping surface. With the particle size becomes smaller, the surface roughness and subsurface crack depth decreases. When the particle size was changed to 1.5µm, the surface roughness Ra was reduced to 24.0nm and the maximum subsurface crack was 1.2µm. The efficiency of grinding is higher than lapping. Plastic removal can be achieved by changing the process parameters. Material removal was mostly in brittle fracture when grinding with 325# diamond wheel. Plow scratches and chipping pits were found on the ground surface. The surface roughness Ra was 17.7nm and maximum subsurface crack depth was 5.8 µm. When grinding with 8000# diamond wheel, the material removal was in plastic flow. Plastic scratches were found on the surface. A smooth surface of roughness Ra 2.5nm without any subsurface cracks was obtained. Atomic scale removal was possible in cluster magnetorheological finishing with diamond abrasive size of 0.5 µm. A super smooth surface eventually obtained with a roughness of Ra 0.4nm without any subsurface crack.

Method and apparatus for subsurface exploration

NASA Technical Reports Server (NTRS)

Wilcox, Brian (Inventor)

2002-01-01

A subsurface explorer (SSX) for exploring beneath the terrestrial surface of planetary bodies such as the Earth, Mars, or comets. This exploration activity utilizes appropriate sensors and instrument to evaluate the composition, structure, mineralogy and possibly biology of the subsurface medium, as well as perhaps the ability to return samples of that medium back to the surface. The vehicle comprises an elongated skin or body having a front end and a rear end, with a nose piece at the front end for imparting force to composition material of the planetary body. Force is provided by a hammer mechanism to the back side of a nose piece from within the body of the vehicle. In the preferred embodiment, a motor spins an intermediate shaft having two non-uniform threads along with a hammer which engages these threads with two conical rollers. A brake assembly halts the rotation of the intermediate shaft, causing the conical roller to spin down the non-uniform thread to rapidly and efficiently convert the rotational kinetic energy of the hammer into translational energy.

Opportunities and challenges for the application of SP measurements to monitor subsurface flow (Invited)

NASA Astrophysics Data System (ADS)

Jackson, M.; Vinogradov, J.; MacAllister, D.; Butler, A. P.; Leinov, E.; Zhang, J.

2013-12-01

Measurements of self-potential (SP) have been proposed or applied to monitor flow in the shallow subsurface in numerous settings, including volcanoes, earthquake zones, geothermal fields and hydrocarbon reservoirs, to detect leaks from dams, tanks and embankments, and to characterize groundwater flow and hydraulic properties. To interpret the measurements, it is generally assumed that the SP is dominated by the streaming potential, arising from the drag of excess electrical charge in the diffuse part of the electrical double layer at the mineral-fluid interfaces. The constitutive equation relating electrical current density j to the driving forces ▽V and ▽P is then j = -σ▽V -σC▽P=-σ▽V + Qv (1) where V is the streaming potential, P is the water pressure, σ is the saturated rock conductivity, v is the Darcy velocity, C is the streaming potential coupling coefficient, and Q is the excess charge transported by the flow. Equation (1) shows that there is a close relationship between flow properties of interest, such as the pressure gradient or Darcy velocity, and the streaming potential component of the SP. Hence SP measurements are an attractive method to monitor subsurface flow. However, the problem with interpreting the measurements is that both C and Q can vary over orders of magnitude, in response to variations in pore-water salinity, temperature, rock texture, and the presence of NAPLs in the pore-space. Moreover, additional current sources may be present if there are gradients in concentration or temperature, arising from differential rates of ion migration down gradient (diffusion potentials), and because of charge exclusion from the pore-space (exclusion potentials). In general, these additional current sources are neglected. This talk suggests a potential new opportunity for the application of SP measurements to monitor subsurface flow, in which the signal of interest arises from salinity rather than pressure gradients. Saline intrusion into freshwater aquifers is a global problem, threatening the water supply of millions of people in coastal settlements. Abstraction rates could be much more efficiently managed if encroaching saline water could be detected before it arrived at the borehole. However, current monitoring is based largely on borehole conductivity measurements, which requires a dense network of monitoring boreholes to map the saline front. Recent laboratory and field experiments suggest that the concentration gradient associated with the front generates an SP signal which can be detected at an abstraction well prior to the arrival of the front, potentially allowing monitoring using a comparatively cheap array of non-polarising borehole electrodes. Current challenges in interpreting SP measurements for subsurface flow are also discussed, particularly the use of models to predict the values of C and Q. The importance of accounting for the pore-level distribution of flow and excess charge in such models is emphasised, and a way forward is suggested in which pore-scale network models, used previously to predict relative permeability and capillary pressure, are extended to include charge transport at the pore-level.

Complexation of Eu(III), Pb(II), and U(VI) with a Paramecium glycoprotein: Microbial transformation of heavy elements in the aquatic environment.

PubMed

Kozai, Naofumi; Sakamoto, Fuminori; Tanaka, Kazuya; Ohnuki, Toshihiko; Satoh, Takahiro; Kamiya, Tomihiro; Grambow, Bernd

2018-04-01

This study investigated the interaction of inorganic aqueous Eu(III), Pb(II), and U(VI) with Paramecium sp., a representative single-celled protozoan that lives in freshwater. Living and prekilled Paramecium cells were tested. The prekilled cells were killed with a fixative. After 24 h exposure of the cells to inorganic aqueous solutions containing Eu(III) or U(VI), analyses by microparticle-induced X-ray emission with a focused beam (<1 μm) did not detect Eu and U in the living cells, whereas Eu and U were detected in the prekilled cells. Size exclusion chromatography coupled with on-line ultraviolet-visible detection and elemental detection by inductively coupled plasma mass spectrometry of the aqueous phases collected after the living cell experiments revealed that a fraction of the Eu, Pb, and U in the aqueous phase bound to a large (ca. 250 kDa) Paramecium biomolecule and formed a metal-organic complex. The characteristics of the biomolecule were consistent with those of the soluble glycoproteins covering the surfaces of Paramecium cells. These results show that Paramecium cells transform inorganic aqueous Eu, Pb, and U to organic complexes. This paper discusses the relation between this novel complexation and the sorption of these heavy elements on Paramecium cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Impact of CO 2 on the Evolution of Microbial Communities Exposed to Carbon Storage Conditions, Enhanced Oil Recovery, and CO 2 Leakage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulliver, Djuna; Gregory, Kelvin B.; Lowry, Gregorgy V.

Geologic carbon storage (GCS) is a crucial part of a proposed mitigation strategy to reduce the anthropogenic carbon dioxide (CO 2) emissions to the atmosphere. During this process, CO 2 is injected as super critical carbon dioxide (SC-CO 2) in confined deep subsurface storage units, such as saline aquifers and depleted oil reservoirs. The deposition of vast amounts of CO 2 in subsurface geologic formations could unintentionally lead to CO 2 leakage into overlying freshwater aquifers. Introduction of CO 2 into these subsurface environments will greatly increase the CO 22 concentration and will create CO 2 concentration gradients that drivemore » changes in the microbial communities present. While it is expected that altered microbial communities will impact the biogeochemistry of the subsurface, there is no information available on how CO 2 gradients will impact these communities. The overarching goal of this project is to understand how CO 2 exposure will impact subsurface microbial communities at temperatures and pressures that are relevant to GCS and CO 2 leakage scenarios. To meet this goal, unfiltered, aqueous samples from a deep saline aquifer, a depleted oil reservoir, and a fresh water aquifer were exposed to varied concentrations of CO 2 at reservoir pressure and temperature. The microbial ecology of the samples was examined using molecular, DNA-based techniques. The results from these studies were also compared across the sites to determine any existing trends. Results reveal that increasing CO 2 leads to decreased DNA concentrations regardless of the site, suggesting that microbial processes will be significantly hindered or absent nearest the CO 2 injection/leakage plume where CO 2 concentrations are highest. At CO 2 exposures expected downgradient from the CO 2 plume, selected microorganisms emerged as dominant in the CO 2 exposed conditions. Results suggest that the altered microbial community was site specific and highly dependent on pH. The site-dependent results suggest a limited ability to predict the emerging dominant species for other CO 2 exposed environments. This study improves the understanding of how a subsurface microbial community may respond to conditions expected from GCS and CO 2 leakage. This is the first step for understanding how a CO 2-altered microbial community may impact injectivity, permanence of stored CO 2, and subsurface water quality. Future work with microbial communities from new subsurface sites would increase the current understanding of this project. Additionally, incorporation of metagenomic methods would increase understanding of potential microbial processes that may be prevalent in CO 2 exposed environments.« less

Impact of CO 2 on the Evolution of Microbial Communities Exposed to Carbon Storage Conditions, Enhanced Oil Recovery, and CO 2 Leakage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulliver, Djuna M.; Gregory, Kelvin B.; Lowry, Gregory V.

Geologic carbon storage (GCS) is a crucial part of a proposed mitigation strategy to reduce the anthropogenic carbon dioxide (CO 2) emissions to the atmosphere. During this process, CO 2 is injected as super critical carbon dioxide (SC-CO 2) in confined deep subsurface storage units, such as saline aquifers and depleted oil reservoirs. The deposition of vast amounts of CO 2 in subsurface geologic formations could unintentionally lead to CO 2 leakage into overlying freshwater aquifers. Introduction of CO 2 into these subsurface environments will greatly increase the CO 2 concentration and will create CO 2 concentration gradients that drivemore » changes in the microbial communities present. While it is expected that altered microbial communities will impact the biogeochemistry of the subsurface, there is no information available on how CO 2 gradients will impact these communities. The overarching goal of this project is to understand how CO 2 exposure will impact subsurface microbial communities at temperatures and pressures that are relevant to GCS and CO 2 leakage scenarios. To meet this goal, unfiltered, aqueous samples from a deep saline aquifer, a depleted oil reservoir, and a fresh water aquifer were exposed to varied concentrations of CO 2 at reservoir pressure and temperature. The microbial ecology of the samples was examined using molecular, DNA-based techniques. The results from these studies were also compared across the sites to determine any existing trends. Results reveal that increasing CO 2 leads to decreased DNA concentrations regardless of the site, suggesting that microbial processes will be significantly hindered or absent nearest the CO 2 injection/leakage plume where CO 2 concentrations are highest. At CO 2 exposures expected downgradient from the CO 2 plume, selected microorganisms emerged as dominant in the CO 2 exposed conditions. Results suggest that the altered microbial community was site specific and highly dependent on pH. The site-dependent results suggest a limited ability to predict the emerging dominant species for other CO 2-exposed environments. This study improves the understanding of how a subsurface microbial community may respond to conditions expected from GCS and CO 2 leakage. This is the first step for understanding how a CO 2-altered microbial community may impact injectivity, permanence of stored CO 2, and subsurface water quality. Future work with microbial communities from new subsurface sites would increase the current understanding of this project. Additionally, incorporation of metagenomic methods would increase understanding of potential microbial processes that may be prevalent in CO 2 exposed environments.« less

Factors Effecting the Fate and Transport of CL-20 in the Vadose Zone and Groundwater: Final Report 2002 - 2004 SERDP Project CP-1255

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szecsody, James E.; Riley, Robert G.; Devary, Brooks J.

2005-06-01

This SERDP-funded project was initiated to investigate the fate of CL-20 in the subsurface environment, with a focus on identification and quantification of geochemical and microbial reactions of CL-20. CL-20 can be released to the surface and subsurface terrestrial environment by: a) manufacturing processes, b) munition storage, and c) use with low order detonation or unexploded ordnance. The risk of far-field subsurface migration was assessed through labora-tory experiments with a variety of sediments and subsurface materials to quantify processes that control CL-20 sorption-limited migration and degradation. Results of this study show that CL-20 will exhibit differing behavior in the subsurfacemore » terrestrial environment: 1. CL-20 on the sediment surface will photodegrade and interact with plants/animals (described in other SERDP projects CU 1254, 1256). CL-20 will exhibit greater sorption in humid sediments to organic matter. Transport will be solubility limited (i.e., low CL-20 aqueous solubility). 2. CL-20 infiltration into soils (<2 m) from spills will be subject to sorption to soil organic matter (if present), and low to high biodegradation rates (weeks to years) depending on the microbial population (greater in humid environment). 3. CL-20 in the vadose zone (>2 m) will be, in most cases, subject to low sorption and low degradation rates, so would persist in the subsurface environment and be at risk for deep migration. Low water content in arid regions will result in a decrease in both sorption and the degradation rate. Measured degradation rates in unsaturated sediments of years would result in significant subsurface migration distances. 4. CL-20 in groundwater will be subject to some sorption but likely very slow degradation rates. CL-20 sorption will be greater than RDX. Most CL-20 degradation will be abiotic (ferrous iron and other transition metals), because most deep subsurface systems have extremely low natural microbial populations. Degradation rates will range from weeks (iron reducing systems) to years. Although CL-20 will move rapidly through most sediments in the terrestrial environment, subsurface remediation can be utilized for cleanup. Transformation of CL-20 to intermediates can be rapidly accomplished under: a) reducing conditions (CL-20 4.1 min. half-life, RDX 18 min. half-life), b) alkaline (pH >10) conditions, and c) bioremediation with added nutrients. CL-20 degradation to intermediates may be insufficient to mitigate environmental impact, as the toxicity of many of these compounds is unknown. Biostimulation in oxic to reducing systems by carbon and nutrient addition can mineralize CL-20, with the most rapid rates occurring under reducing conditions.« less

Polymerase chain reaction analysis of aqueous humour samples in necrotising retinitis.

PubMed

Tran, T H C; Rozenberg, F; Cassoux, N; Rao, N A; LeHoang, P; Bodaghi, B

2003-01-01

To evaluate the diagnostic value of polymerase chain reaction (PCR) performed on aqueous humour for the detection of viral DNA in patients with necrotising herpetic retinitis. The clinical features and laboratory results of 22 patients (29 eyes) presenting with necrotising herpetic retinitis between March 1999 and June 2001 were reviewed retrospectively. Aqueous humour was obtained after anterior chamber paracentesis and PCR was performed in all cases. Viral DNA was detected in the aqueous humour of 19 patients (86.4%). Epstein-Barr virus (EBV) seroconversion was evidenced in one additional patient. In the acute retinal necrosis (ARN) group (n = 19), varicella zoster virus (VZV) DNA was identified in six patients, herpes simplex virus 1 (HSV-1) DNA in two patients, herpes simplex virus 2 (HSV-2) DNA in four patients, and cytomegalovirus (CMV) genome in four patients. In the progressive outer retinal necrosis (PORN) group (n = 3), VZV DNA was detected in all patients. No sample was positive for more than one virus. PCR analysis of aqueous humour in patients with clinical features of necrotising viral retinitis can provide specific aetiological orientation and the method appears to be safe and highly sensitive.

Polymerase chain reaction analysis of aqueous humour samples in necrotising retinitis

PubMed Central

Tran, T H C; Rozenberg, F; Cassoux, N; Rao, N A; LeHoang, P; Bodaghi, B

2003-01-01

Aim: To evaluate the diagnostic value of polymerase chain reaction (PCR) performed on aqueous humour for the detection of viral DNA in patients with necrotising herpetic retinitis. Methods: The clinical features and laboratory results of 22 patients (29 eyes) presenting with necrotising herpetic retinitis between March 1999 and June 2001 were reviewed retrospectively. Aqueous humour was obtained after anterior chamber paracentesis and PCR was performed in all cases. Results: Viral DNA was detected in the aqueous humour of 19 patients (86.4%). Epstein-Barr virus (EBV) seroconversion was evidenced in one additional patient. In the acute retinal necrosis (ARN) group (n = 19), varicella zoster virus (VZV) DNA was identified in six patients, herpes simplex virus 1 (HSV-1) DNA in two patients, herpes simplex virus 2 (HSV-2) DNA in four patients, and cytomegalovirus (CMV) genome in four patients. In the progressive outer retinal necrosis (PORN) group (n = 3), VZV DNA was detected in all patients. No sample was positive for more than one virus. Conclusions: PCR analysis of aqueous humour in patients with clinical features of necrotising viral retinitis can provide specific aetiological orientation and the method appears to be safe and highly sensitive. PMID:12488268

Dual-Use Applications of Infrared Sensitive Materials

DTIC Science & Technology

1993-06-01

only limit to MCT-based detectors’ market potential is in price. Specialty systems for subsurface imaging (such as buried storage tanks, toxic wastes...and assessment of automotive paint damaged by rust or stone impacts. Since automotive paint is a multi-layered coating, it lends itself to subsurface ... imaging , as well as aerospace aluminum and epoxy composites. Another family of non-destructive evaluation techniques which could use infrared detectors

Temporal GPR Imaging of an Ethanol Release Within a Laboratory-Scaled Sand Tank

EPA Science Inventory

Within the last decade efforts in geophysical detection and monitoring of fossil fuel releases into the subsurface have shown increasing success, including the ability to geophysically detect and delineate enhanced and natural biodegradation and remediation activities. The subst...

Detection of nitrite based on fluorescent carbon dots by the hydrothermal method with folic acid

NASA Astrophysics Data System (ADS)

Lin, Haitao; Ding, Liyun; Zhang, Bingyu; Huang, Jun

2018-05-01

A fluorescent carbon dots probe for the detection of aqueous nitrite was fabricated by a one-pot hydrothermal method, and the transmission electron microscope, X-ray diffractometer, UV-Vis absorption spectrometer and fluorescence spectrophotometer were used to study the property of carbon dots. The fluorescent property of carbon dots influenced by the concentration of aqueous nitrite was studied. The interaction between the electron-donating functional groups and the electron-accepting nitrous acid could account for the quenching effect on carbon dots by adding aqueous nitrite. The products of the hydrolysis of aqueous nitrite performed a stronger quenching effect at lower pH. The relationship between the relative fluorescence intensity of carbon dots and the concentration of nitrite was described by the Stern-Volmer equation (I0/I - 1 = 0.046[Q]) with a fine linearity (R2 = 0.99). The carbon dots-based probe provides a convenient method for the detection of nitrite concentration.

Aqueous origins of bright salt deposits on Ceres

NASA Astrophysics Data System (ADS)

Zolotov, Mikhail Yu.

2017-11-01

Bright materials have been reported in association with impact craters on Ceres. The abundant Na2CO3 and some ammonium salts, NH4HCO3 and/or NH4Cl, were detected in bright deposits within Occator crater with Dawn near infrared spectroscopy. The composition and appearance of the salts suggest their aqueous mobilization and emplacement after formation of the crater. Here we consider origins of the bright deposits through calculation of speciation in the H-C-N-O-Na-Cl water-salt type system constrained by the mass balance of observed salts. Calculations of chemical equilibria show that initial solutions had the pH of ∼10. The temperature and salinity of solutions could have not exceeded ∼273 K and ∼100 g per kg H2O, respectively. Freezing models reveal an early precipitation of Na2CO3·10H2O followed by minor NaHCO3. Ammonium salts precipitate near eutectic from brines enriched in NH4+, Cl- and Na+. A late-stage precipitation of NaCl·2H2O is modeled for solution compositions with added NaCl. Calculated eutectics are above 247 K. The apparently unabundant ammonium and chloride salts in Occator's deposits imply a rapid emplacement without a compositional evolution of solution. Salty ice grains could have deposited from post-impact ballistic plumes formed through low-pressure boiling of subsurface solutions. Hydrated and ammonium salts are unstable at maximum temperatures of Ceres' surface and could decompose through space weathering. Occator's ice-free salt deposits formed through a post-depositional sublimation of ice followed by dehydration of Na2CO3·10H2O and NaHCO3 to Na2CO3. In other regions, excavated and exposed bright materials could be salts initially deposited from plumes and accumulated at depth via post-impact boiling. The lack of detection of sulfates and an elevated carbonate/chloride ratio in Ceres' materials suggest an involvement of compounds abundant in the outer solar system.

Partitioning Tracer Test for Detection, Estimation, and Remediation Performance Assessment of Subsurface Nonaqueous Phase Liquids

NASA Astrophysics Data System (ADS)

Jin, Minquan; Delshad, Mojdeh; Dwarakanath, Varadarajan; McKinney, Daene C.; Pope, Gary A.; Sepehrnoori, Kamy; Tilburg, Charles E.; Jackson, Richard E.

1995-05-01

In this paper we present a partitioning interwell tracer test (PITT) technique for the detection, estimation, and remediation performance assessment of the subsurface contaminated by nonaqueous phase liquids (NAPLs). We demonstrate the effectiveness of this technique by examples of experimental and simulation results. The experimental results are from partitioning tracer experiments in columns packed with Ottawa sand. Both the method of moments and inverse modeling techniques for estimating NAPL saturation in the sand packs are demonstrated. In the simulation examples we use UTCHEM, a comprehensive three-dimensional, chemical flood compositional simulator developed at the University of Texas, to simulate a hypothetical two-dimensional aquifer with properties similar to the Borden site contaminated by tetrachloroethylene (PCE), and we show how partitioning interwell tracer tests can be used to estimate the amount of PCE contaminant before remedial action and as the remediation process proceeds. Tracer tests results from different stages of remediation are compared to determine the quantity of PCE removed and the amount remaining. Both the experimental (small-scale) and simulation (large-scale) results demonstrate that PITT can be used as an innovative and effective technique to detect and estimate the amount of residual NAPL and for remediation performance assessment in subsurface formations.

Partitioning tracer test for detection, estimation, and remediation performance assessment of subsurface nonaqueous phase liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, M.; Delshad, M.; Dwarakanath, V.

1995-05-01

In this paper we present a partitioning interwell tracer test (PITT) technique for the detection, estimation, and remediation performance assessment of the subsurface contaminated by nonaqueous phase liquids (NAPLs). We demonstrate the effectiveness of this technique by examples of experimental and simulation results. The experimental results are from partitioning tracer experiments in columns packed with Ottawa sand. Both the method of moments and inverse modeling techniques for estimating NAPL saturation in the sand packs are demonstrated. In the simulation examples we use UTCHEM, a comprehensive three-dimensional, chemical flood compositional simulator developed at the University of Texas, to simulate a hypotheticalmore » two-dimensional aquifer with properties similar to the Borden site contaminated by tetrachloroethylene (PCE), and we show how partitioning interwell tracer tests can be used to estimate the amount of PCE contaminant before remedial action and as the remediation process proceeds. Tracer test results from different stages of remediation are compared to determine the quantity of PCE removed and the amount remaining. Both the experimental (small-scale) and simulation (large-scale) results demonstrate that PITT can be used as an innovative and effective technique to detect and estimate the amount of residual NAPL and for remediation performance assessment in subsurface formations. 43 refs., 10 figs., 1 tab.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiusheng, Y., E-mail: qsyan@gdut.edu.cn; Senkai, C., E-mail: senkite@sina.com; Jisheng, P., E-mail: panjisheng@gdut.edu.cn

Different machining processes were used in the single crystal SiC wafer machining. SEM was used to observe the surface morphology and a cross-sectional cleavages microscopy method was used for subsurface cracks detection. Surface and subsurface cracks characteristics of single crystal SiC wafer in abrasive machining were analysed. The results show that the surface and subsurface cracks system of single crystal SiC wafer in abrasive machining including radial crack, lateral crack and the median crack. In lapping process, material removal is dominated by brittle removal. Lots of chipping pits were found on the lapping surface. With the particle size becomes smaller,more » the surface roughness and subsurface crack depth decreases. When the particle size was changed to 1.5µm, the surface roughness Ra was reduced to 24.0nm and the maximum subsurface crack was 1.2µm. The efficiency of grinding is higher than lapping. Plastic removal can be achieved by changing the process parameters. Material removal was mostly in brittle fracture when grinding with 325# diamond wheel. Plow scratches and chipping pits were found on the ground surface. The surface roughness Ra was 17.7nm and maximum subsurface crack depth was 5.8 µm. When grinding with 8000# diamond wheel, the material removal was in plastic flow. Plastic scratches were found on the surface. A smooth surface of roughness Ra 2.5nm without any subsurface cracks was obtained. Atomic scale removal was possible in cluster magnetorheological finishing with diamond abrasive size of 0.5 µm. A super smooth surface eventually obtained with a roughness of Ra 0.4nm without any subsurface crack.« less

Modern water/rock reactions in Oman hyperalkaline peridotite aquifers and implications for microbial habitability

NASA Astrophysics Data System (ADS)

Miller, Hannah M.; Matter, Jürg M.; Kelemen, Peter; Ellison, Eric T.; Conrad, Mark E.; Fierer, Noah; Ruchala, Tyler; Tominaga, Masako; Templeton, Alexis S.

2016-04-01

The Samail ophiolite in Oman is undergoing modern hydration and carbonation of peridotite and may host a deep subsurface biosphere. Previous investigations of hyperalkaline fluids in Oman have focused on fluids released at surface seeps, which quickly lose their reducing character and precipitate carbonates upon contact with the O2/CO2-rich atmosphere. In this work, geochemical analysis of rocks and fluids from the subsurface provides new insights into the operative reactions in serpentinizing aquifers. Serpentinite rock and hyperalkaline fluids (pH > 10), which exhibit millimolar concentrations of Ca2+, H2 and CH4, as well as variable sulfate and nitrate, were accessed from wells situated in mantle peridotite near Ibra and studied to investigate their aqueous geochemistry, gas concentrations, isotopic signatures, mineralogy, Fe speciation and microbial community composition. The bulk mineralogy of drill cuttings is dominated by olivine, pyroxene, brucite, serpentine and magnetite. At depth, Fe-bearing brucite is commonly intermixed with serpentine, whereas near the surface, olivine and brucite are lost and increased magnetite and serpentine is detected. Micro-Raman spectroscopy reveals at least two distinct generations of serpentine present in drill cuttings recovered from several depths from two wells. Fe K-edge X-ray absorption near-edge spectroscopy (XANES) analysis of the lizardite shows a strong tetrahedral Fe coordination, suggesting a mixture of both Fe(II) and Fe(III) in the serpentine. Magnetite veins are also closely associated with this second generation serpentine, and 2-10 μm magnetite grains overprint all minerals in the drill cuttings. Thus we propose that the dissolved H2 that accumulates in the subsurface hyperalkaline fluids was evolved through low temperature oxidation and hydration of relict olivine, as well as destabilization of pre-existing brucite present in the partially serpentinized dunites and harzburgites. In particular, we hypothesize that Fe-bearing brucite is currently reacting with dissolved silica in the aquifer fluids to generate late-stage magnetite, additional serpentine and dissolved H2. Dissolved CH4 in the fluids exhibits the most isotopically heavy carbon in CH4 reported in the literature thus far. The CH4 may have formed through abiotic reduction of dissolved CO2 or through biogenic pathways under extreme carbon limitation. The methane isotopic composition may have also been modified by significant methane oxidation. 16S rRNA sequencing of DNA recovered from filtered hyperalkaline well fluids reveals an abundance of Meiothermus, Thermodesulfovibrionaceae (sulfate-reducers) and Clostridia (fermenters). The fluids also contain candidate phyla OP1 and OD1, as well as Methanobacterium (methanogen) and Methylococcus sp. (methanotroph). The composition of these microbial communities suggests that low-temperature hydrogen and methane generation, coupled with the presence of electron acceptors such as nitrate and sulfate, sustains subsurface microbial life within the Oman ophiolite.

Detecting Defects Within Soil-Bentonite Slurry Cutoff Walls Using Electrical Resistivity Methods

NASA Astrophysics Data System (ADS)

Aborn, L.; Jacob, R. W.; Mucelli, A.

2016-12-01

Installed in the subsurface, vertical cutoff walls may limit groundwater movement. The effectiveness of these walls can be undermined by defects, for example high permeability material, within the wall. An efficient way of detecting these defects in a soil-bentonite slurry cutoff wall has yet to be established. We installed an approximately 200-meter long and 7-meter deep soil-bentonite slurry cutoff wall for the purposes of research. The wall was constructed adjacent to a natural wetland, the Montandon Marsh near Lewisburg, PA. The wall is composed of soil-bentonite backfill and was designed to be a typical low permeability material. We evaluate the capability of non-invasive geophysical techniques, specifically electrical resistivity, to detect high permeability defects that are expected to have higher electrical resistivity values than the backfill material. The laboratory measured electrical resistivity of the backfill used for construction was 12.27-ohm meters. During construction, designed defects of saturated fine-grained sand bags were deployed at different positions and depths within the wall. To create larger defects multiple bags were tied together. Laboratory resistivity testing of the sand and the filled sand bags indicates values between 125-ohm meters at full saturation and 285-ohm meters at partial saturation. Post construction, we collected electrical resistivity data using a 28-channel system along the centerline of the cutoff wall, which indicated the backfill material to have a resistivity value of 15-ohm meters. The electrical resistivity profile was affected by the sidewalls of the trench, as expected, which may explain the difference between laboratory results and field measurements. To minimize the sidewalls obscuring the defects, we developed electrodes that are pushed into the backfill at different depths to collect subsurface resistivity. Different arrays and electrode spacings are being tested. Our presentation will report the most effective method for detecting defects within a soil-bentonite cutoff wall.

Finite Element Modeling of the Thermographic Inspection for Composite Materials

NASA Technical Reports Server (NTRS)

Bucinell, Ronald B.

1996-01-01

The performance of composite materials is dependent on the constituent materials selected, material structural geometry, and the fabrication process. Flaws can form in composite materials as a result of the fabrication process, handling in the manufacturing environment, and exposure in the service environment to anomalous activity. Often these flaws show no indication on the surface of the material while having the potential of substantially degrading the integrity of the composite structure. For this reason it is important to have available inspection techniques that can reliably detect sub-surface defects such as inter-ply disbonds, inter-ply cracks, porosity, and density changes caused by variations in fiber volume content. Many non-destructive evaluation techniques (NDE) are capable of detecting sub-surface flaws in composite materials. These include shearography, video image correlation, ultrasonic, acoustic emissions, and X-ray. The difficulty with most of these techniques is that they are time consuming and often difficult to apply to full scale structures. An NDE technique that appears to have the capability to quickly and easily detect flaws in composite structure is thermography. This technique uses heat to detect flaws. Heat is applied to the surface of a structure with the use of a heat lamp or heat gun. A thermographic camera is then pointed at the surface and records the surface temperature as the composite structure cools. Flaws in the material will cause the thermal-mechanical material response to change. Thus, the surface over an area where a flaw is present will cool differently than regions where flaws do not exist. This paper discusses the effort made to thermo-mechanically model the thermography process. First the material properties and physical parameters used in the model will be explained. This will be followed by a detailed discussion of the finite element model used. Finally, the result of the model will be summarized along with recommendations for future work.