Science.gov

Sample records for influences governing subsurface

  1. Government influence on patient organizations.

    PubMed

    Van de Bovenkamp, Hester M; Trappenburg, Margo J

    2011-12-01

    Patient organizations increasingly play an important role in health care decision-making in Western countries. The Netherlands is one of the countries where this trend has gone furthest. In the literature some problems are identified, such as instrumental use of patient organizations by care providers, health insurers and the pharmaceutical industry. To strengthen the position of patient organizations government funding is often recommended as a solution. In this paper we analyze the ties between Dutch government and Dutch patient organizations to learn more about the effects of such a relationship between government and this part of civil society. Our study is based on official government documents and existing empirical research on patient organizations. We found that government influence on patient organizations has become quite substantial with government influencing the organizational structure of patient organizations, the activities these organizations perform and even their ideology. Financing patient organizations offers the government an important means to hold them accountable. Although the ties between patient organizations and the government enable the former to play a role that can be valued as positive by both parties, we argue that they raise problems as well which warrant a discussion on how much government influence on civil society is acceptable.

  2. The influence of subsurface hydrodynamics on convective precipitation

    NASA Astrophysics Data System (ADS)

    Rahman, A. S. M. M.; Sulis, M.; Kollet, S. J.

    2014-12-01

    The terrestrial hydrological cycle comprises complex processes in the subsurface, land surface, and atmosphere, which are connected via complex non-linear feedback mechanisms. The influence of subsurface hydrodynamics on land surface mass and energy fluxes has been the subject of previous studies. Several studies have also investigated the soil moisture-precipitation feedback, neglecting however the connection with groundwater dynamics. The objective of this study is to examine the impact of subsurface hydrodynamics on convective precipitation events via shallow soil moisture and land surface processes. A scale-consistent Terrestrial System Modeling Platform (TerrSysMP) that consists of an atmospheric model (COSMO), a land surface model (CLM), and a three-dimensional variably saturated groundwater-surface water flow model (ParFlow), is used to simulate hourly mass and energy fluxes over days with convective rainfall events over the Rur catchment, Germany. In order to isolate the effect of groundwater dynamics on convective precipitation, two different model configurations with identical initial conditions are considered. The first configuration allows the groundwater table to evolve through time, while a spatially distributed, temporally constant groundwater table is prescribed as a lower boundary condition in the second configuration. The simulation results suggest that groundwater dynamics influence land surface soil moisture, which in turn affects the atmospheric boundary layer (ABL) height by modifying atmospheric thermals. It is demonstrated that because of this sensitivity of ABL height to soil moisture-temperature feedback, the onset and magnitude of convective precipitation is influenced by subsurface hydrodynamics. Thus, the results provide insight into the soil moisture-precipitation feedback including groundwater dynamics in a physically consistent manner by closing the water cycle from aquifers to the atmosphere.

  3. Influence of intraocular lens subsurface nanoglistenings on functional visual acuity

    PubMed Central

    Miyata, Kazunori; Hayashidera, Takeshi; Iida, Masaharu; Takada, Keita; Minami, Keiichiro; Oshika, Tetsuro

    2017-01-01

    To investigate the influence of intraocular lens subsurface nanoglistenings (SSNGs) on functional visual acuity (FVA), thirty-nine eyes of 29 patients were examined in this study. The SSNG group comprised 19 eyes of 14 patients (75.7± 5.4 years, mean ± standard deviation), and the control group comprised 20 eyes of 15 patients (73.6 ± 6.5 years). The SSNGs were diagnosed on the basis of the typical whitish IOL appearance upon slit-lamp examination and results of densitometry regarding surface light scattering using Scheimpflug images. The FVA measurement system (AS-28; Kowa, Aichi, Japan) was used to examine changes in continuous visual acuity (VA) over time, and visual function parameters such as FVA, visual maintenance ratio (VMR), maximum VA, minimum VA, standard deviation of VA, and number of blinks were assessed. The results were compared between the SSNG and control groups, and correlations of FVA parameters with the intensity of surface light scattering, time after surgery, and age were also evaluated. There were significant differences in VMR (P = 0.035) and standard deviation of VAs (P = 0.031) between the two groups, although no significant differences were found in baseline VA, FVA, maximum VA, minimum VA, and number of blinks. None of the FVA parameters showed any significant correlations with the intensity of surface light scattering, time after surgery, or age. There is a possibility that VA is unstable during a continuous gazing task in patients with SSNGs. PMID:28328997

  4. Influence Of Subsurface Biosphere On Geochemical Fluxes From Diffuse Hydrothermal Fluids: Direct Measurement Of Subsurface Hydrogen Oxidation

    NASA Astrophysics Data System (ADS)

    Wankel, S. D.; Germanovich, L. N.; Lilley, M. D.; Genc, G.; DiPerna, C. J.; Bradley, A. S.; Olson, E. J.; Girguis, P. R.

    2011-12-01

    After decades of research on hydrothermal vent biogeochemistry, quantification of low-temperature diffusive geochemical fluxes remains elusive and limits our ability to place constraints on their role in global geochemical cycles. Quantifying the relative differences in geochemical composition, in particular of energy-rich compounds such as H2 and CH4, between focused high-temperature and diffuse low-temperature hydrothermal fluids can allow the estimation of metabolic rates in the underlying subsurface biosphere. Towards shortening the gap in our understanding of geochemical and microbial dynamics of the subsurface biosphere, we deployed an in situ mass spectrometer (ISMS) and low flow meter to quantify biologically relevant volatiles in a wide range of flow regimes and temperatures. Here we present coupled in situ chemical analyses and flow measurements that enable quantification of geochemical fluxes from a diversity of diffuse and focused vents along the Juan de Fuca Ridge hydrothermal system. We show that geochemical flux from diffuse vents can equal or exceed that emanating from hot, focused vents. Notably, hydrogen concentrations in fluids emerging from diffuse vents are 50% to 80% lower than predicted. We attribute the loss of hydrogen in diffuse vent fluids to microbial consumption in the subsurface, and suggest that subsurface microbial communities can significantly influence hydrothermal geochemical fluxes to the deep ocean.

  5. RESEARCH ACTIVITIES AT U.S. GOVERNMENT AGENCIES IN SUBSURFACE REACTIVE TRANSPORT MODELING

    EPA Science Inventory

    The fate of contaminants in the environment is controlled by both chemical reactions and transport phenomena in the subsurface. Our ability to understand the significance of these processes over time requires an accurate conceptual model that incorporates the various mechanisms ...

  6. RESEARCH ACTIVITIES AT U.S. GOVERNMENT AGENCIES IN SUBSURFACE REACTIVE TRANSPORT MODELING

    EPA Science Inventory

    The fate of contaminants in the environment is controlled by both chemical reactions and transport phenomena in the subsurface. Our ability to understand the significance of these processes over time requires an accurate conceptual model that incorporates the various mechanisms ...

  7. The Influence of Plant Root Systems on Subsurface Flow: Implications for Slope Stability

    EPA Science Inventory

    Although research has explained how plant roots mechanically stabilize soils, in this article we explore how root systems create networks of preferential flow and thus influence water pressures in soils to trigger landslides. Root systems may alter subsurface flow: Hydrological m...

  8. The Influence of Plant Root Systems on Subsurface Flow: Implications for Slope Stability

    EPA Science Inventory

    Although research has explained how plant roots mechanically stabilize soils, in this article we explore how root systems create networks of preferential flow and thus influence water pressures in soils to trigger landslides. Root systems may alter subsurface flow: Hydrological m...

  9. Influence of spatial and temporal variability of subsurface soil moisture and temperature on vapour intrusion

    NASA Astrophysics Data System (ADS)

    Bekele, Dawit N.; Naidu, Ravi; Chadalavada, Sreenivasulu

    2014-05-01

    A comprehensive field study was conducted at a site contaminated with chlorinated solvents, mainly trichloroethylene (TCE), to investigate the influence of subsurface soil moisture and temperature on vapour intrusion (VI) into built structures. Existing approaches to predict the risk of VI intrusion into buildings assume homogeneous or discrete layers in the vadose zone through which TCE migrates from an underlying source zone. In reality, the subsurface of the majority of contaminated sites will be subject to significant variations in moisture and temperature. Detailed site-specific data were measured contemporaneously to evaluate the impact of spatial and temporal variability of subsurface soil properties on VI exposure assessment. The results revealed that indoor air vapour concentrations would be affected by spatial and temporal variability of subsurface soil moisture and temperature. The monthly monitoring of soil-gas concentrations over a period of one year at a depth of 3 m across the study site demonstrated significant variation in TCE vapour concentrations, which ranged from 480 to 629,308 μg/m3. Soil-gas wells at 1 m depth exhibited high seasonal variability in TCE vapour concentrations with a coefficient of variation 1.02 in comparison with values of 0.88 and 0.74 in 2 m and 3 m wells, respectively. Contour plots of the soil-gas TCE plume during wet and dry seasons showed that the plume moved across the site, hence locations of soil-gas monitoring wells for human risk assessment is a site specific decision. Subsurface soil-gas vapour plume characterisation at the study site demonstrates that assessment for VI is greatly influenced by subsurface soil properties such as temperature and moisture that fluctuate with the seasons of the year.

  10. Factors governing selection of operating frequency for subsurface- imaging synthetic-aperture radar

    SciTech Connect

    Brock, B.C.; Patitz, W.E.

    1993-12-31

    A subsurface-imaging synthetic-aperture radar (SISAR) has potential for application in areas as diverse as non-proliferation programs for nuclear weapons to environmental monitoring. However, subsurface imaging is complicated by propagation loss in the soil and surface-clutter response. Both the loss and surface-clutter response depend on the operating frequency. This paper examines several factors which provide a basis for determining optimum frequencies and frequency ranges which will allow synthetic-aperture imaging of buried targets. No distinction can be made between objects at different heights when viewed with a conventional imaging radar (which uses a one-dimensional synthetic aperture), and the return from a buried object must compete with the return from the surface clutter. Thus, the signal-to-clutter ratio is an appropriate measure of performance for a SISAR. A parameter-based modeling approach is used to model the complex dielectric constant of the soil from measured data obtained from the literature. Theoretical random-surface scattering models, based on statistical solutions to Maxwell`s equations, are used to model the clutter. These models are combined to estimate the signal-to-clutter ratio for canonical targets buried in several soil configurations. Results indicate that the HF spectrum (3--30), although it could be used to detect certain targets under some conditions, has limited practical value for use with SISAR, while the upper VIHF through UHF spectrum ({approximately}100 MHz - 1 GHz) shows the most promise for a general purpose SISAR system. Recommendations are included for additional research.

  11. Influence of soil spatial variability on surface and subsurface flow at a vegetative buffer strip scale.

    NASA Astrophysics Data System (ADS)

    Gatel, Laura; Lauvernet, Claire; Carluer, Nadia; Paniconi, Claudio; Leblois, Etienne

    2015-04-01

    The objective of this study is to evaluate the influence of soil hydrodynamic characteristics variability on surface and subsurface flow at a vegetative buffer strip scale, using mecanistic modeling. Cathy (CATchment HYdrology, Camporese et al. 2010) is a research physically based model able to simulate coupled surface/subsurface flow. The evaluation of soil hydrodynamic characteristics variability is based essentially on saturated hydraulic conductivity because of its large spatial variability in the 3 dimensions and its important influence on flow pathways, as well as its high influence on the model output variables. After testing the model sensitivity to some input variables, to the boundary conditions and to the mesh definition, the work focuses on hydraulic conductivity parametrization. The study was first conducted with uniform (by horizons) conductivity domains based on field measurements. In a second step, heterogeneous fields were generated by a statistical tool which allows the user to choose the statistical law (in this case, lognormal or Gauss), the hydraulic conductivity auto-correlation length and the possibility to condition the fields with measured points. With all these different ways to represent spatial variability of hydraulic conductivity, model simulated surface and subsurface fluxes consistent with datasets from artificial run-off experiments on an French wineyard hillslope (Morcille catchment, Beaujolais, France). Model simulations are evaluated and compared to observations on several criteria : consistency, stability, interaction with water table, etc...

  12. Influence of subsurface biosphere on geochemical fluxes from diffuse hydrothermal fluids

    NASA Astrophysics Data System (ADS)

    Wankel, Scott D.; Germanovich, Leonid N.; Lilley, Marvin D.; Genc, Gence; Diperna, Christopher J.; Bradley, Alexander S.; Olson, Eric J.; Girguis, Peter R.

    2011-07-01

    Hydrothermal vents along mid-ocean systems host unique, highly productive biological communities, based on microbial chemoautotrophy, that thrive on the sulphur, metals, nitrogen and carbon emitted from the vents into the deep ocean. Geochemical studies of vents have centred on analyses of high-temperature, focused hydrothermal vents, which exhibit very high flow rates and are generally considered too hot for microbial life. Geochemical fluxes and metabolic activity associated with habitable, lower temperature diffuse fluids remain poorly constrained. As a result, little is known about the extent to which microbial communities, particularly in the subsurface, influence geochemical flux from more diffuse flows. Here, we estimate the net flux of methane, carbon dioxide and hydrogen from diffuse and focused hydrothermal vents along the Juan de Fuca ridge, using an in situ mass spectrometer and flowmeter. We show that geochemical flux from diffuse vents can equal or exceed that emanating from hot, focused vents. Notably, hydrogen concentrations in fluids emerging from diffuse vents are 50% to 80% lower than predicted. We attribute the loss of hydrogen in diffuse vent fluids to microbial consumption in the subsurface, and suggest that subsurface microbial communities can significantly influence hydrothermal geochemical fluxes to the deep ocean.

  13. Influence of cutting parameters on the depth of subsurface deformed layer in nano-cutting process of single crystal copper.

    PubMed

    Wang, Quanlong; Bai, Qingshun; Chen, Jiaxuan; Su, Hao; Wang, Zhiguo; Xie, Wenkun

    2015-12-01

    Large-scale molecular dynamics simulation is performed to study the nano-cutting process of single crystal copper realized by single-point diamond cutting tool in this paper. The centro-symmetry parameter is adopted to characterize the subsurface deformed layers and the distribution and evolution of the subsurface defect structures. Three-dimensional visualization and measurement technology are used to measure the depth of the subsurface deformed layers. The influence of cutting speed, cutting depth, cutting direction, and crystallographic orientation on the depth of subsurface deformed layers is systematically investigated. The results show that a lot of defect structures are formed in the subsurface of workpiece during nano-cutting process, for instance, stair-rod dislocations, stacking fault tetrahedron, atomic clusters, vacancy defects, point defects. In the process of nano-cutting, the depth of subsurface deformed layers increases with the cutting distance at the beginning, then decreases at stable cutting process, and basically remains unchanged when the cutting distance reaches up to 24 nm. The depth of subsurface deformed layers decreases with the increase in cutting speed between 50 and 300 m/s. The depth of subsurface deformed layer increases with cutting depth, proportionally, and basically remains unchanged when the cutting depth reaches over 6 nm.

  14. Technical geothermal potential of urban subsurface influenced by land surface effects

    NASA Astrophysics Data System (ADS)

    Rivera, Jaime A.; Blum, Philipp; Bayer, Peter

    2016-04-01

    Changes in land use are probably one of the most notorious anthropogenic perturbations in urban environments. They significantly change the coupled thermal regime at the ground surface leading in most cases to increased ground surface temperatures (GST). The associated elevated vertical heat fluxes act at different scales and can influence the thermal conditions in several tens of meters in the subsurface. Urban subsurface thus often stores a higher amount of heat than less affected rural surroundings. The stored heat is regarded as a potential source of low-enthalpy geothermal energy to supply the heating energy demands in urban areas. In this work, we explore the technical geothermal potential of urban subsurface via ground coupled heat pumps with borehole heat exchangers (BHE). This is tackled by semi-analytical line-source equations. The commonly used response factors or g-functions are modified to include transient land surface effects. By including this additional source of heat, the new formulation allows to analyse the effect of pre-existing urban warming as well as different exploitation schemes fulfilling standard renewable and sustainable criteria. In our generalized reference scenario, it is demonstrated that energy gains for a single BHE may be up to 40 % when compared to non-urbanized conditions. For a scenario including the interaction of multiple BHEs, results indicate that it would be possible to supply between 6 % and 27 % of the heating demands in Central European urban settlements in a renewable way. The methodology is also applied to a study case of the city of Zurich, Switzerland, where the detailed evolution of land use is available.

  15. The influence of subsurface flow on lake formation and north polar lake distribution on Titan

    NASA Astrophysics Data System (ADS)

    Horvath, David G.; Andrews-Hanna, Jeffrey C.; Newman, Claire E.; Mitchell, Karl L.; Stiles, Bryan W.

    2016-10-01

    climatic lake effect. These results reveal that subsurface flow through aquifers plays an important role in Titan's hydrological cycle, and exerts a strong influence over the distribution, size, and volatile budgets of Titan's lakes.

  16. The Influence of Subsurface Karst Terrain on Hydrology and Hydrogeology in Southwestern Victoria, Australia

    NASA Astrophysics Data System (ADS)

    Perveen, F.; Webb, J.; Dresel, E.; Hekmeijer, P.; Zydor, H.

    2012-12-01

    A detailed study, in collaboration with Department of Primary Industries (DPI), Victoria, has been carried out in three small subcatchments of southwestern Victoria (total area 8.4 km2), which are characterised by varying degrees of influence of a subsurface karst terrain. Lithological logs and downhole geophysics (gamma and bulk conductivity - EM39) on 15 bores within the catchments were supplemented by 2D electrical resistivity vertical profiling, and showed that the middle to late Miocene Port Campbell Limestone is present at shallow depths (~5 m) in two catchments, and somewhat deeper (>70 m) in the third catchment. The limestone is overlain by early Pliocene clay-rich Dorodong Sands. The topography of the third catchment is characterised by shallow closed depressions. Detailed hydrogeological cross-sections using groundwater levels in the bores show closed depressions within the potentiometric surface, that are attributed to the presence of subsurface conduits within the highly permeable limestone, verified by the variable hydraulic conductivity values ( 0.005 - 0.545m/day) obtained from single borehole recovery tests. Stream hydrographs reveal that there is virtually no surface runoff from one subcatchment, due to leakage into a conduit in the underlying limestone. A perched water table is also found in the same area. Thus the study area shows the typical karst features of a highly heterogeneous terrain with massive connectivity between surface water and groundwater regimes, despite the fact that the limestone is overlain by the clay-rich Dorodong Sands.

  17. Hydro-environmental changes and their influence on the subsurface environment in the context of urban development.

    PubMed

    Yoshikoshi, Akihisa; Adachi, Itsu; Taniguchi, Tomomasa; Kagawa, Yuichi; Kato, Masahiro; Yamashita, Akio; Todokoro, Taiko; Taniguchi, Makoto

    2009-04-15

    The relationship between urban development and hydro-environmental change, particularly with regard to the subsurface environment is examined for three coastal cities affected by Asian monsoons (Tokyo and Osaka in Japan, and Bangkok in Thailand). Major differences in subsurface changes among these cities are closely related to city size, urban structure, and the timing, stage and extent of urbanization as well as the natural environment. The work shows that the urban development has not affected the Bangkok subsurface hydro-environment in the same way it has in Tokyo and Osaka. Three reasons for the difference account for this, (1) Bangkok's abundant annual rainfall, (2) Bangkok has the smallest ratio of impervious pavement surface area, meaning that surface water can more easily infiltrate underground., (3) the degree and extent of urbanization. Bangkok's subsurface hydro-environment has not been heavily affected because underground development has not yet reached deep subterranean areas. By researching yet more cities, at different stages of urbanization to that of Tokyo, Osaka and Bangkok, we plan to quantitatively examine urbanization and its influence on subsurface hydro-environments. This research will help limit damage to developing cities that are not yet experiencing subsurface failures but which are expected to confront these problems in the future.

  18. Influence of chlorothalonil on the removal of organic matter in horizontal subsurface flow constructed wetlands.

    PubMed

    Casas-Zapata, Juan C; Ríos, Karina; Florville-Alejandre, Tomás R; Morató, Jordi; Peñuela, Gustavo

    2013-01-01

    This study investigates the effects of chlorothalonil (CLT) on chemical oxygen demand (COD) and dissolved organic carbon (DOC) in pilot-scale horizontal subsurface flow constructed wetlands (HSSFCW) planted with Phragmites australis. Physicochemical parameters of influent and effluent water samples, microbial population counting methods and statistical analysis were used to evaluate the influence of CLT on organic matter removal efficiency. The experiments were conducted on four planted replicate wetlands (HSSFCW-Pa) and one unplanted control wetland (HSSFCW-NPa). The wetlands exhibited high average organic matter removal efficiencies (HSSFCW-Pa: 80.6% DOC, 98.0% COD; HSSFCW-NPa: 93.2% DOC, 98.4% COD). The addition of CLT did not influence organic removal parameters. In all cases CLT concentrations in the effluent occurred in concentrations lower than the detection limit of the analytical method. Microbial population counts from HSSFCW-Pa showed significant correlations among different microbial groups and with different physicochemical variables. The apparent independence of organic matter removal and CLT inputs, along with the CLT depletion observed in effluent samples demonstrated that HSSFCW are a viable technology for the treatment of agricultural effluents contaminated with organo-chloride pesticides like CLT.

  19. Microbial and chemical factors influencing methane production in laboratory incubations of low-rank subsurface coals

    USGS Publications Warehouse

    Harris, Stephen H.; Smith, Richard L.; Barker, Charles E.

    2008-01-01

    Lignite and subbituminous coals were investigated for their ability to support microbial methane production in laboratory incubations. Results show that naturally-occurring microorganisms associated with the coals produced substantial quantities of methane, although the factors influencing this process were variable among different samples tested. Methanogenic microbes in two coals from the Powder River Basin, Wyoming, USA, produced 140.5-374.6 mL CH4/kg ((4.5-12.0 standard cubic feet (scf)/ton) in response to an amendment of H2/CO2. The addition of high concentrations (5-10 mM) of acetate did not support substantive methane production under the laboratory conditions. However, acetate accumulated in control incubations where methanogenesis was inhibited, indicating that acetate was produced and consumed during the course of methane production. Acetogenesis from H2/CO2 was evident in these incubations and may serve as a competing metabolic mode influencing the cumulative amount of methane produced in coal. Two low-rank (lignite A) coals from Fort Yukon, Alaska, USA, demonstrated a comparable level of methane production (131.1-284.0 mL CH4/kg (4.2-9.1 scf/ton)) in the presence of an inorganic nutrient amendment, indicating that the source of energy and organic carbon was derived from the coal. The concentration of chloroform-extractable organic matter varied by almost three orders of magnitude among all the coals tested, and appeared to be related to methane production potential. These results indicate that substrate availability within the coal matrix and competition between different groups of microorganisms are two factors that may exert a profound influence on methanogenesis in subsurface coal beds.

  20. Identifying (subsurface) anthropogenic heat sources that influence temperature in the drinking water distribution system

    NASA Astrophysics Data System (ADS)

    Agudelo-Vera, Claudia M.; Blokker, Mirjam; de Kater, Henk; Lafort, Rob

    2017-09-01

    The water temperature in the drinking water distribution system and at customers' taps approaches the surrounding soil temperature at a depth of 1 m. Water temperature is an important determinant of water quality. In the Netherlands drinking water is distributed without additional residual disinfectant and the temperature of drinking water at customers' taps is not allowed to exceed 25 °C. In recent decades, the urban (sub)surface has been getting more occupied by various types of infrastructures, and some of these can be heat sources. Only recently have the anthropogenic sources and their influence on the underground been studied on coarse spatial scales. Little is known about the urban shallow underground heat profile on small spatial scales, of the order of 10 m × 10 m. Routine water quality samples at the tap in urban areas have shown up locations - so-called hotspots - in the city, with relatively high soil temperatures - up to 7 °C warmer - compared to the soil temperatures in the surrounding rural areas. Yet the sources and the locations of these hotspots have not been identified. It is expected that with climate change during a warm summer the soil temperature in the hotspots can be above 25 °C. The objective of this paper is to find a method to identify heat sources and urban characteristics that locally influence the soil temperature. The proposed method combines mapping of urban anthropogenic heat sources, retrospective modelling of the soil temperature, analysis of water temperature measurements at the tap, and extensive soil temperature measurements. This approach provided insight into the typical range of the variation of the urban soil temperature, and it is a first step to identifying areas with potential underground heat stress towards thermal underground management in cities.

  1. An Analysis of the Treatment of Corporate Influence on Government by United States History and American Government High School Textbooks

    ERIC Educational Resources Information Center

    Neumann, Richard

    2014-01-01

    This article reports on an investigation to explore the possibility that ideology might be expressed in the treatment of corporate influence on federal government by social studies textbooks. Two textbooks were examined in the study--United States history and American government. Corporate influence involves activities that affect election and…

  2. An Analysis of the Treatment of Corporate Influence on Government by United States History and American Government High School Textbooks

    ERIC Educational Resources Information Center

    Neumann, Richard

    2014-01-01

    This article reports on an investigation to explore the possibility that ideology might be expressed in the treatment of corporate influence on federal government by social studies textbooks. Two textbooks were examined in the study--United States history and American government. Corporate influence involves activities that affect election and…

  3. Corroboration for the influence of a component of solar irradiance on subsurface radon signals

    NASA Astrophysics Data System (ADS)

    Steinitz, G.; Piatibratova, O.; Kotlarsky, P.; Sturrock, P.; Maritn, C.

    2012-04-01

    Rn-222 occurs at highly varying levels as a trace component in subsurface air (geogas). This high variability is traced by alpha and gamma activity due to the decay of radon and its progeny. Nuclear radiation from radon in geogas and in experiments using air+radon within a confined volume exhibits systematic temporal variations. These variations are composed of periodic and non-periodic signals spanning several orders of magnitude in time - from annual to daily and sub-daily durations. Analysis of extensive data sets from three key sites 200 km apart in the arid desert of southern Israel [1-3] and from a 5-year experiment using alpha and gamma detectors [4] demonstrate that the periodic variations, observed to a depth of >100 meters, are related to an above surface driver probably due to a component of solar irradiance. Insight was also derived from the long term variations in the geological and the experimental time series [5], indicated by the occurrence of multi-year variations, and clear semiannual and ternary annual signals which are in addition to the annual periodicity. New confirmations are based on recognizing further cyclic phenomena, some of which are not linked with Earth related periodicities. A likehood analysis of the alpha and gamma time series in a long-term experiment is performed. A Combined Power Statistic formed from the gamma, alpha-H and alpha-L sensors inside the experimental tank shows that the time series of the gamma radiation contains an annual periodicity as well as a clear semi-annual and possibly a ternary-annual periodicity. The same analysis also resolves additional periodicities in the frequency range of 10-15 yr-1 in the gamma time series which are indicative of a relationship to rotation of the sun around its axis [6]. Observation of solar periodicities in the temporal pattern of the nuclear radiation of radon is a significant independent substantiation for the notion of the influence of a component in solar irradiance. An

  4. Influencing and impacting the profession through governance opportunities.

    PubMed

    Drenkard, Karen N

    2015-01-01

    In addition to board leadership of health care organizations and corporations, there are strategic opportunities for nurses to participate in professional association boards and commissions and expert panels. These boards have specific and unique challenges and opportunities, and it is important for nurse leaders to serve in shaping the direction of the profession. Nursing as a profession has an opening to solve many of the care delivery issues that face the country. A strategic contribution to association boards and commissions can influence the health care delivery system changes needed to improve quality of care, access to care, and reducing costs. This article describes similarities and differences of service on association boards and commissions compared with organizational and corporate boards. Through these leadership roles, the larger community can observe influential nurses in an essential role. These leadership opportunities, including membership boards, commissions, and content expert panels, call for a special understanding of those governance structures and the contributions that nurse leaders can make to impact health care. Association and membership organizations have undergone many changes in the past 10 years, and new models of governance and leadership have been called into play. There are challenges and opportunities in serving on these boards and commissions. Maximizing the leadership and governance roles of this type of service is a critical contribution that nurses can make to impact the profession of nursing and the greater health care system.

  5. Investigating the influence of subsurface heterogeneity on chemical weathering in the critical zone using high resolution reactive transport models

    NASA Astrophysics Data System (ADS)

    Pandey, S.; Rajaram, H.

    2014-12-01

    The critical zone (CZ) represents a major life-sustaining realm of the terrestrial surface. The processes controlling the development and transformation of the CZ are important to continued health of the planet as human influence continues to grow. The CZ encompasses the shallow subsurface, a region of reaction, unsaturated flow, and transport. Chemical weathering in the subsurface is one of the important processes involved in the formation and functioning of the CZ. We present two case studies of reactive transport modeling to investigate the influence of subsurface heterogeneity and unsaturated flow on chemical weathering processes in the CZ. The model is implemented using the reactive transport code PFLOTRAN. Heterogeneity in subsurface flow is represented using multiple realizations of conductive fracture networks in a hillslope cross-section. The first case study is motivated by observations at the Boulder Creek Critical Zone Observatory (BCCZO) including extensive hydrologic and geochemical datasets. The simulations show that fractures greatly enhance weathering as compared to a homogeneous porous medium. Simulations of north-facing slope hydrology with prolonged snowmelt pulses also increases weathering rates, showing the importance of slope aspect on weathering intensity. Recent work elucidates deteriorating water quality caused by climate change in the CZ of watersheds where acid rock drainage (ARD) occurs. The more complex reactions of ARD require a customized kinetic reaction module with PFLOTRAN. The second case study explores the mechanisms by which changes in hydrologic forcing, air and ground temperatures, and water table elevations influence ARD. For instance, unreacted pyrite exposed by a water table drop was shown to produce a 125% increase in annual pyrite oxidization rate, which provides one explanation for increased ARD.

  6. Evaluating the Competitive Use of the Subsurface: The Influence of Energy Storage and Production in Groundwater

    NASA Astrophysics Data System (ADS)

    Helmig, R.; Becker, B.; Flemisch, B.

    2015-12-01

    The natural subsurface is gaining in importance for a variety of engineering applications related to energy supply. At the same time it is already utilized in many ways. On the one hand, the subsurface with its groundwater system represents the most important source of drinking water; on the other hand, it contains natural resources such as petroleum, natural gas and coal. In recent years, the subsurface has been gaining importance as a resource of energy and as an energy and waste repository. It can serve as a short-, medium- or long-term storage medium for energy in various forms, e.g. in the form of methane (CH4), hydrogen (H2) or compressed air. The subsurface is also attracting increasing interest as a natural source of energy, regarding, for instance, the extraction of fossil methane by hydraulic fracturing or the utilization of geothermal energy as a renewable energy source. As a result, with increasing exploitation, resource conflicts are becoming more and more common and complex. Modeling concepts for simulating multiphase flow that can reproduce the high complexity of the underlying processes in an efficient way need to be developed. The application of these model concepts is of great importance with respect to feasibility, risk analysis, storage capacity and sensitivity issues. This talk will give an overview on possible utilization conflicts in subsurface systems and how the groundwater is affected. It will focus on presenting fundamental properties and functions of a compositional multiphase system in a porous medium and introduce basic multiscale and multiphysics concepts as well as formulate conser­vation laws for simulating energy storage in the subsurface. Large-scale simulations that show the general applicability of the modeling concepts of such complicated natural systems, especially the impact on the groundwater of simultaneously using geothermal energy and storing chemical and thermal energy, and how such real large-scale systems provide a

  7. Influence of alternative and conventional farming practices on subsurface drainage and water quality.

    PubMed

    Oquist, K A; Strock, J S; Mulla, D J

    2007-01-01

    Agricultural runoff contributes nutrients to nonpoint-source pollution of surface waters. This study was conducted to investigate the potential use of alternative farming practices to improve water quality. The study examined the effects of both alternative and conventional farming practices on subsurface drainage and nitrogen and phosphorus loss through subsurface drainage from glacial till soils (i.e., Calciaquolls, Endoaquolls, Eutrudepts, Hapludolls) in southwest Minnesota. Alternative farming practices included organic management practices, species biodiversity, and/or practices that include reduced inputs of synthetic fertilizer and pesticides. Conventional farming practices include corn-soybean (Zea mays L.-Glycine max L., respectively) rotations and their associated recommended fertilizer rates as well as pesticide usage. Precipitation was highly variable during the 3-yr study period including a below-average year (2003), an average year (2002), and an above-average year (2004). Results indicate that alternative farming practices reduced subsurface drainage discharge by 41% compared with conventional practices. Flow-weighted mean nitrate-nitrogen (nitrate N) concentrations during tile flow were 8.2 and 17.2 mg L(-1) under alternative and conventional farming practices, respectively. Alternative farming practices reduced nitrate N losses by between 59 and 62% in 2002 and 2004 compared with conventional practices. Ammonium-nitrogen (ammonium N), orthophosphorus, and total phosphorus losses in subsurface drainage were very low and did not pose a substantial risk of pollution. Results suggest that alternative farming practices have the potential to reduce agricultural impacts on water quality.

  8. Influence of subsurface heterogeneity on observed borehole temperatures at a mountain permafrost site in the Upper Engadine, Swiss Alps

    NASA Astrophysics Data System (ADS)

    Schneider, S.; Hoelzle, M.; Hauck, C.

    2012-04-01

    Permafrost in high mountain areas occurs in a large variety of surface and subsurface material within short distances. This work presents a nine-year (2002 - 2011) data set of borehole temperatures for five different (sub-) surface materials from the high alpine permafrost area, Murtèl-Corvatsch, Switzerland (Haeberli et al. (1988) and Hanson & Hoelzle (2005)). The influence of the material on the thermal regime was investigated by borehole temperature data, the temperature at the top of the permafrost (TTOP-concept) and the apparent thermal diffusivity (ATD). The results show no consistent subsurface temperature trends since 2002 within the uppermost 6 meters. Rather, the thermal regime is predominantly influenced by the composition of the subsurface material and the thickness and duration of the snow cover. At all sites the subsurface temperatures were the lowest when the snow thickness was less than 1m. As pointed out in Luetschg et al. (2008), it could be confirmed, that the longer the non-insulating snow cover lasts in autumn, the colder is the ground surface temperature (GST) through the entire year. At all sites the cooling during autumn/ winter and the duration of the zero curtain in spring had a stronger influence on the interannual variability of the thermal regime than the temperature increase during summer. At coarse blocky, ice-rich sites no changes in active layer depth were observed. Rather, the ATD values of the active layer and the high temperature transport rate of 5.6 K m-1 d-1 confirm a high thermal response of the active layer. Within coarse blocky material, the air ventilation (as described in Wakonigg (1996)) and the seasonal production of ice seem to be the main factors for permafrost occurrence in high alpine regions. While temperatures within the talus slope are close to 0 °C and a stable permafrost regime is observed, the subsurface of the fine-grained site (where convective and advective airflow can be neglected) showed positive

  9. Subsurface transport of phosphorus in riparian floodplains: influence of preferential flow paths.

    PubMed

    Fuchs, John W; Fox, Garey A; Storm, Daniel E; Penn, Chad J; Brown, Glenn O

    2009-01-01

    For phosphorus (P) transport from upland areas to surface water systems, the primary transport mechanism is typically considered to be surface runoff with subsurface transport assumed negligible. However, certain local conditions can lead to an environment where subsurface transport may be significant. The objective of this research was to determine the potential of subsurface transport of P along streams characterized by cherty or gravel subsoils, especially the impact of preferential flow paths on P transport. At a field site along the Barren Fork Creek in northeastern Oklahoma, a trench was installed with the bottom at the topsoil/alluvial gravel interface. Fifteen piezometers were installed surrounding the trench to monitor flow and transport. In three experiments, water was pumped into the trench from the Barren Fork Creek to maintain a constant head. At the same time, a conservative tracer (Rhodamine WT) and/or potassium phosphate solution were injected into the trench at concentrations at 3 and 100 mg/L for Rhodamine WT and at 100 mg/L for P. Laboratory flow-cell experiments were also conducted on soil material <2 mm in size to determine the effect that flow velocity had on P sorption. Rhodamine WT and P were detected in some piezometers at equivalent concentrations as measured in the trench, suggesting the presence of preferential flow pathways and heterogeneous interaction between streams and subsurface transport pathways, even in nonstructured, coarse gravel soils. Phosphorus transport was retarded in nonpreferential flow paths. Breakthrough times were approximately equivalent for Rhodamine WT and P suggesting no colloidal-facilitated P transport. Results from laboratory flow-cell experiments suggested that higher velocity resulted in less P sorption for the alluvial subsoil. Therefore, differences in flow rates between preferential and nonpreferential flow pathways in the field led to variable sorption. The potential for nutrient subsurface transport

  10. Influence of dissimilatory metal reduction on fate of organic and metal contaminants in the subsurface

    USGS Publications Warehouse

    Lovely, Derek R.; Anderson, Robert T.

    2000-01-01

    Geobacter become dominant members of the microbial community when Fe(III)-reducing conditions develop as the result of organic contamination, or when Fe(III) reduction is artificially stimulated. These results suggest that further understanding of the ecophysiology of Geobacter species would aid in better prediction of the natural attenuation of organic contaminants under anaerobic conditions and in the design of strategies for the bioremediation of subsurface metal contamination.

  11. Higher Education Governance: Balancing Institutional and Market Influences.

    ERIC Educational Resources Information Center

    Richardson, Richard C., Jr.; Bracco, Kathy Reeves; Callan, Patrick M.; Finney, Joni E.

    This report presents the results of a multi-state study of state governing structures for higher education, focusing on the complexity of general patterns of higher education governance. The study focused on higher education governance in seven states--California, Florida, Georgia, Illinois, Michigan, New York, and Texas--and was based on a review…

  12. Tetracycline Resistance in the Subsurface of a Poultry Farm: Influence of Poultry Wastes

    NASA Astrophysics Data System (ADS)

    You, Y.; Ball, W. P.; Ward, M. J.; Hilpert, M.

    2007-12-01

    Concentrated animal feeding operations (CAFOs) are considered to be important man-made reservoir of antibiotic resistant bacteria. Using the electromagnetic induction (EMI) method of geophysical characterization, we measured the apparent subsurface electrical conductivity (ECa) at a CAFO site in order to assess the movement of pollutants associated with animal waste. The map of ECa and other available data suggest that (1) soil surrounding a poultry litter storage shed is contaminated by poultry waste, (2) a contamination plume in the subsurface emanates from that shed, and (3) the development of that plume is due to groundwater flow. We focused on understanding the spread of tetracycline resistance (Tc\\tiny R), because tetracycline is one of the most frequently used antibiotics in food animal production and therefore probably used at our field site. Microbiological experiments show the presence of Tc\\tiny R bacteria in the subsurface and indicate higher concentrations in the top soil than in the aquifer. Environmental DNA was extracted to identify CAFO- associated Tc\\tiny R genes and to explore a link between the presence of Tc\\tiny R and CAFO practices. A "shot-gun" cloning approach is under development to target the most prevalent Tc\\tiny R gene. This gene will be monitored in future experiments, in which we will study the transmission of Tc\\tiny R to naive E.~coli under selective pressure of Tc. Experimental results will be used to develop a mathematical/numerical model in order to describe the transmission process and to subsequently make estimates regarding the large-scale spread of antibiotic resistance.

  13. The Influence of Subsurface Processes on the Concentration and Composition of Dissolved Organic Matter

    NASA Astrophysics Data System (ADS)

    Aiken, G.

    2004-12-01

    Microbial and geochemical interactions in the subsurface can result in chemical alteration and fractionation of organic matter thereby altering the nature and composition of dissolved organic matter (DOM) in groundwater and in surface waters dominated by ground water inflow. In this paper, the results of a study designed to determine the effectiveness of subsurface processes for removing DOM from two surface waters in Southern California will be presented. The recharge zones immediately underneath two infiltration basins, Anaheim Lake and Kraemer Basin, were found to be very active with respect to changes in the amounts and reactivities of the DOM. In all cases, dissolved organic carbon (DOC) concentrations decrease as water moves from the basins into the regional aquifer system. Data obtained from relatively shallow wells located near the infiltration basins (travel times less than 30 days) indicate that a large amount of DOM is removed during the first stages of transport in the subsurface. Parcels of water from both basins were followed for up to 360 days as the water moved away from the infiltration basins. DOC concentrations and specific ultraviolet absorbance (SUVA), an excellent indicator of aromatic carbon content of DOM, continued to decrease substantially with a general decrease in DOC concentration of about 70%. Regardless of initial DOC concentrations present in the infiltration basins, values decreased to approximately 1.3 mg C/L at the furthest points sampled. Analyses of organic matter isolates obtained by chromatographic methods indicated greater removal of aromatic molecules and preservation of branched chain aliphatic and alicyclic structures more resistant to biodegradation. Compared to samples from a wide range of environments, the DOM in the down gradient wells most closely resembled similar materials obtained from other groundwater systems and those of microbial origin. These results suggest that subsurface processes are significant in the

  14. Influence of inorganic and organic nutrients on aerobic biodegradation and on the adaptation response of subsurface microbial communities

    SciTech Connect

    Swindoll, C.M.; Aelion, C.M.; Pfaender, F.K.

    1988-01-01

    The influence of inorganic and organic amendments on the mineralization of ethylene dibromide, rho-nitrophenol, phenol, and toluene was examined in subsurface soil samples from a pristine aquifer near Lula, Oklahoma. The responses indicate that the metabolic abilities and nutrient requirements of ground water microorganisms vary substantially within an aquifer. In some samples, additions of inorganic nutrients resulted in a more rapid adaptation to the test substrate and a higher rate of metabolism, indicating that metabolism may have been limited by these nutrients. In other samples from the same aquifer layer, inorganic amendments had little or no influence on mineralization. In general, the addition of multiple inorganic nutrients resulted in a greater enhancement of degradation than did the addition of single substances. Additions of alternate carbon sources, such as glucose or amino acids, inhibited the mineralization of the xenobiotic substrates. This inhibition appears to be the result of the preferential utilization of the more easily degradable carbon amendments.

  15. Vegetation Influence on Regional Climate Change: A 3D Integrated Atmospheric-Surface-Subsurface Analysis

    NASA Astrophysics Data System (ADS)

    Davison, J. H.; Hwang, H.; Sudicky, E. A.; Lin, J. C.

    2013-12-01

    Human induced land-use change has been shown to be one of the major contributing factors to anthropogenic regional climate change. The transition from densely vegetated forests with deep root zones to shallow rooted agricultural ecosystems drastically limits the natural buffering capacity of deep groundwater during severe drought conditions. In order to quantify the magnitude of climate change from altered ecosystems, we employed the 3D model HydroGeoSphere, an integrated variably-saturated subsurface/surface flow and heat transport model, coupled with a simplified zero-dimensional atmospheric boundary layer model to simulate an extended seasonal drought period. It is found that during drought conditions, trees with deep root zones are capable of maintaining higher evapotranspiration rates, higher latent heat fluxes, and a damped atmospheric temperature response. In contrast, grasses with shallow root zones have minimal evapotranspiration rates, lower latent heat fluxes, and a rapid and sharp atmospheric temperature response. On the whole, converting a naturally wooded ecosystem to a farmland or pasture effectively decreases the available water in the subsurface for transpiration subsequently amplifying the atmospheric response to severe weather.

  16. Simulating the influence of physicochemical parameters on subsurface oil on beaches: preliminary results.

    PubMed

    Bernabeu, A M; Rey, D; Lago, A; Vilas, F

    2010-08-01

    Monitoring of sandy beaches after the Prestige oil spill revealed thick subsurface layers (up to 1m thick) of grey-coloured sand. These horizons were sometimes found under more than 3m of clean sand. Examination of the sand by electron microscopy confirmed that the colouring was due to oil-coated sand grains, and revealed a sequence of degradation of buried oil. Further analysis of the sand revealed high concentrations of hydrocarbon in the oil-coated sand and that the main biomarkers were indicative of biodegradation, even though the oil was buried. A set of experiments was designed to analyze the evolution of oil from tar balls to coatings. The results revealed that biodegradation is a secondary process in the changes that take place in the buried oil, and that water flow slows down the appearance of grey sand and that low salinity may hinder the oil degradation process. Copyright 2010 Elsevier Ltd. All rights reserved.

  17. Does clinical governance influence the appropriateness of hospital stay?

    PubMed

    Specchia, Maria Lucia; Poscia, Andrea; Volpe, Massimo; Parente, Paolo; Capizzi, Silvio; Cambieri, Andrea; Damiani, Gianfranco; Ricciardi, Walter; De Belvis, Antonio Giulio

    2015-04-03

    Clinical Governance provides a framework for assessing and improving clinical quality through a single coherent program. Organizational appropriateness is aimed at achieving the best health outcomes and the most appropriate use of resources. The goal of the present study is to verify the likely relationship between Clinical Governance and appropriateness of hospital stay. A cross-sectional study was conducted in 2012 in an Italian Teaching Hospital. The OPTIGOV(©) (Optimizing Health Care Governance) methodology was used to quantify the level of implementation of Clinical Governance globally and in its main dimensions. Organizational appropriateness was measured retrospectively using the Italian version of the Appropriateness Evaluation Protocol to analyze a random sample of medical records for each clinical unit. Pearson-correlation and multiple linear regression were used to test the relationship between the percentage of inappropriate days of hospital stay and the Clinical Governance implementation levels. 47 Units were assessed. The percentage of inappropriate days of hospital stay showed an inverse correlation with almost all the main Clinical Governance dimensions. Adjusted multiple regression analysis resulted in a significant association between the percentage of inappropriate days and the overall Clinical Governance score (β = -0.28; p < 0.001; R-squared = 0.8). EBM and Clinical Audit represented the Clinical Governance dimensions which had the strongest association with organizational appropriateness. This study suggests that the evaluation of both Clinical Governance and organizational appropriateness through standardized and repeatable tools, such as OPTIGOV(©) and AEP, is a key strategy for healthcare quality. The relationship between the two underlines the central role of Clinical Governance, and especially of EBM and Clinical Audit, in determining a rational improvement of appropriateness levels.

  18. Influence of biofilms on the movement of colloids in porous media. Implications for colloid facilitated transport in subsurface environments.

    PubMed

    Leon Morales, Carlos Felipe; Strathmann, Martin; Flemming, Hans-Curt

    2007-05-01

    Colloid transport through porous media can be influenced by the presence of biofilms. Sterile and non-sterile sand columns were investigated using Laponite RD as model colloid and a highly mucoid strain of Pseudomonas aeruginosa as model biofilm former. Laponite RD was marked specifically by fluorescent complexes with rhodamine 6G. Breakthrough curves (BTCs) were used as parameters for determination of colloid transport characteristics. In the sterile columns, the colloid was mobile (collision efficiencies from 0.05 to 0.08) both after the presence of Na(+) and Ca(2+) ions followed by deionised water influent. In the biofilm-grown column, the same treatment did not result in colloid retention in the case of Na(+) exposure, but in altered or enhanced colloid transport. In the case of Ca(2+) ions exposure, colloid retention increased with biofilm age. After 3 weeks, almost complete retention was observed. Similar observations were made in columns packed with material from slow sand filtration units. These data reveal the complex interactions between biofilms, cations and colloid transport. Changes in the electrolyte composition of water percolating the subsurface can frequently occur and will result in different colloid transport characteristics with regard to the dominating species of ions and the relative abundance of microbial biofilms. This has to be considered when modelling colloid transport through the subsurface.

  19. Influence of hydrological, biogeochemical and temperature transients on subsurface carbon fluxes in a flood plain environment

    SciTech Connect

    Arora, Bhavna; Spycher, Nicolas F.; Steefel, Carl I.; Molins, Sergi; Bill, Markus; Conrad, Mark E.; Dong, Wenming; Faybishenko, Boris; Tokunaga, Tetsu K.; Wan, Jiamin; Williams, Kenneth H.; Yabusaki, Steven B.

    2016-02-01

    Flood plains play a potentially important role in the global carbon cycle. The accumulation of organic matter in flood plains often induces the formation of chemically reduced groundwater and sediments along riverbanks. In this study, our objective is to evaluate the cumulative impact of such reduced zones, water table fluctuations, and temperature gradients on subsurface carbon fluxes in a flood plain at Rifle, Colorado located along the Colorado River. 2-D coupled variably-saturated, non-isothermal flow and biogeochemical reactive transport modeling was applied to improve our understanding of the abiotic and microbially mediated reactions controlling carbon dynamics at the Rifle site. Model simulations considering only abiotic reactions (thus ignoring microbial reactions) underestimated CO2 partial pressures observed in the unsaturated zone and severely underestimated inorganic (and overestimated organic) carbon fluxes to the river compared to simulations with biotic pathways. Both model simulations and field observations highlighted the need to include microbial contributions from chemolithoautotrophic processes (e.g., Fe?2 and S-2 oxidation) to match locally-observed high CO2 concentrations above reduced zones. Observed seasonal variations in CO2 concentrations in the unsaturated zone could not be reproduced without incorporating temperature gradients in the simulations. Incorporating temperature fluctuations resulted in an increase in the annual groundwater carbon fluxes to the river by 170 % to 3.3 g m-2 d-1, while including water table variations resulted in an overall decrease in the simulated fluxes. We conclude that spatial microbial and redox zonation as well as temporal fluctuations of temperature and water table depth contribute significantly to subsurface carbon fluxes in flood plains and need to be represented appropriately in model simulations.

  20. Sub-surface alloying largely influences graphene nucleation and growth over transition metal substrates.

    PubMed

    Zhang, Liying; Zhao, Xingju; Xue, Xinlian; Shi, Jinlei; Li, Chong; Ren, Xiaoyan; Niu, Chunyao; Jia, Yu; Guo, Zhengxiao; Li, Shunfang

    2015-11-11

    Sub-surface alloying (SSA) can be an effective approach to tuning surface functionalities. Focusing on Rh(111) as a typical substrate for graphene nucleation, we show strong modulation by SSA atoms of both the energetics and kinetics of graphene nucleation simulated by first-principles calculations. Counter-intuitively, when the sub-surface atoms are replaced by more active solute metal elements to the left of Rh in the periodic table, such as the early transition metals (TMs), Ru and Tc, the binding between a C atom and the substrate is weakened and two C atoms favor dimerization. Alternatively, when the alloying elements are the late TMs to the right of Rh, such as the relatively inert Pd and Ag, the repulsion between the two C atoms is enhanced. Such distinct results can be well addressed by the delicately modulated activities of the surface host atoms in the framework of the d-band theory. More specifically, we establish a very simple selection rule for optimizing the metal substrate for high quality graphene growth: the introduction of an early (late) solute TM in the SSA lowers (raises) the d-band center and the activity of the top-most host metal atoms, weakening (strengthening) the C-substrate binding, meanwhile both energetically and kinetically facilitating (hindering) the graphene nucleation, and simultaneously promoting (suppressing) the orientation disordering the graphene domains. Importantly, our preliminary theoretical results also show that such a simple rule is also proposed to be operative for graphene growth on the widely invoked Cu(111) catalytic substrate.

  1. Government Influence and Community Involvement on Abstinence-Only Programs in 1999 and 2003

    ERIC Educational Resources Information Center

    Gusrang, Jamie L.; Cheng, Simon

    2010-01-01

    In this study, we compare federal government influence on abstinence-only programs in 1999 and 2003 to better see how shifts in the federal government's sex education polices impacted other government and community actors. Using data from the Sex Education in America Surveys (SEAS), we find that changes in federal policy, particularly after the…

  2. Government Influence and Community Involvement on Abstinence-Only Programs in 1999 and 2003

    ERIC Educational Resources Information Center

    Gusrang, Jamie L.; Cheng, Simon

    2010-01-01

    In this study, we compare federal government influence on abstinence-only programs in 1999 and 2003 to better see how shifts in the federal government's sex education polices impacted other government and community actors. Using data from the Sex Education in America Surveys (SEAS), we find that changes in federal policy, particularly after the…

  3. Clogging influence on metals migration and removal in sub-surface flow constructed wetlands.

    PubMed

    Ranieri, Ezio; Young, Thomas M

    2012-03-15

    Chromium (Cr) and Nickel (Ni) removal from secondary effluent has been evaluated in a four year research program to determine the effectiveness of Sub-Surface Flow (SSF) Constructed Wetlands (cw(s)). Tests were performed in small scale (10 l/h) and full scale (150 m(3)/d) SSF cw(s). Metals removal was also assessed as a function of increased clogging that occurred in the cw(s) over the course of the study. Cr and Ni content were evaluated in sediments at various locations along the flow path and in plant tissues by sampling Phragmites australis roots, stems and leaves. Clogging was evaluated by measuring hydraulic conductivity at the same sampling locations at the beginning and at the end of the experiment. Residence Time Distribution (RTD) curves were also assessed at the beginning and after 48months; the skewness of the RTDs increased over this period. Proportionality between increasing clogging and sediment accumulation of metals was observed, especially for Ni. Adsorption to the original matrix and the accumulated sediment is a removal mechanism consistent with available data.

  4. Influence of the mole penetrator on measurements of heat flow in lunar subsurface layers

    NASA Astrophysics Data System (ADS)

    Wawrzaszek, Roman; Drogosz, Michal; Seweryn, Karol; Banaszkiewicz, Marek; Grygorczuk, Jerzy

    Measuring the thermal gradient in subsurface layers is a basic method of determination the heat flux from the interior of a planetary body to its surface. In case of the Moon, such measurements complemented with the results of theoretical analysis and modeling can significantly improve our understanding of the thermal and geological evolution of the Moon. In practice, temperature gradient measurements are performed by at least two sensors located at different depths under the surface. These sensors will be attached to a penetrator [1] or to a cable pulled behind the penetrator. In both cases the object that carries the sensors, e.g. penetrator, perturb temperature measurements. In our study we analyze a case of two thermal sensors attached to the ends of 350mm long penetrator made of a composite material. In agreement with the studies of other authors we have found that the penetrator should be placed at the depth of 2-3 meters, where periodic changes of the temperature due to variation of solar flux at the surface are significantly smaller than the error of temperature measurement. The most important result of our analysis is to show how to deconvolve the real gradient of the temperature from the measurements perturbed by the penetrator body. In this way it will be possible to more accurately determine heat flux in the lunar regolith. [1] Grygorczuk J., Seweryn K., Wawrzaszek R., Banaszkiewicz M., Insertion of a Mole Pene-trator -Experimental Results, /39th Lunar and Planetary Science Conference /League City, Texas 2008

  5. Influence of lowland forests on subsurface salt accumulation in shallow groundwater areas

    PubMed Central

    Tóth, Tibor; Balog, Kitti; Szabó, András; Pásztor, László; Jobbágy, Esteban G.; Nosetto, Marcelo D.; Gribovszki, Zoltán

    2013-01-01

    In flat sedimentary plains in areas with a sub-humid climate, tree planting on grasslands and arable lands creates strong hydrological shifts. As a result of deep rooting and high water uptake of trees, groundwater levels drop and subsurface salt accumulation increases. Tree planting has expanded globally and in Hungary it reached rates of 15 000 ha year−1, being focused mainly in the Great Hungarian Plain where forests replace grasslands and crops in a region with widespread shallow groundwater. We performed soil and groundwater observations in 31 pairs of forest and control plots in the region, including gradients of initial water table depth and salinity, soil layering, and tree species and age. Accumulated tree biomass was positively correlated with soil salinization rates following tree planting, being also affected by species (poplar > common oak > black locust) and stand age. Differences among tree species effects appeared to be related to their growth rates. Due to downward deep percolation and salt leaching episodes during the Hungarian winters, the observed salt accumulation rates were lower than those described under similar settings in the warmer Argentine Pampas. PMID:25228311

  6. Influences on corporate executive decision behavior in government acquisitions

    NASA Technical Reports Server (NTRS)

    Wetherington, J. R.

    1986-01-01

    This paper presents extensive exploratory research which had as its primary objective, the discovery and determination of major areas of concern exhibited by U.S. corporate executives in the preparation and submittal of proposals and bids to the Federal government. The existence of numerous unique concerns inherent in corporate strategies within the government market environment was established. A determination of the relationship of these concerns to each other was accomplished utilizing statistical factor analysis techniques resulting in the identification of major groupings of management concerns. Finally, using analysis of variance, an analysis and discovery of the interrelationship of the factors to corporate demographics was accomplished. The existence of separate and distinct concerns exhibited by corporate executives when contemplating sales and operations in the government marketplace was established. It was also demonstrated that quantifiable relationships exist between such variables and that the decision behavior exhibited by the responsible executives has an interrelationship to their company's demographics.

  7. Influences on corporate executive decision behavior in government acquisitions

    NASA Technical Reports Server (NTRS)

    Wetherington, J. R.

    1986-01-01

    This paper presents extensive exploratory research which had as its primary objective, the discovery and determination of major areas of concern exhibited by U.S. corporate executives in the preparation and submittal of proposals and bids to the Federal government. The existence of numerous unique concerns inherent in corporate strategies within the government market environment was established. A determination of the relationship of these concerns to each other was accomplished utilizing statistical factor analysis techniques resulting in the identification of major groupings of management concerns. Finally, using analysis of variance, an analysis and discovery of the interrelationship of the factors to corporate demographics was accomplished. The existence of separate and distinct concerns exhibited by corporate executives when contemplating sales and operations in the government marketplace was established. It was also demonstrated that quantifiable relationships exist between such variables and that the decision behavior exhibited by the responsible executives has an interrelationship to their company's demographics.

  8. Governance.

    ERIC Educational Resources Information Center

    Moran, K. D.

    The author notes that two trends appear to be developing in litigation over the governance of the public schools. One trend is increasing participation of organized groups in suits against the schools. The other is a greater volume of litigation dealing with open meeting laws and freedom of information acts. Reflecting the second trend, the…

  9. Governance.

    ERIC Educational Resources Information Center

    Moran, K. D.

    This chapter summarized and analyzes all state supreme court and federal court decisions as well as other significant court decisions affecting the realm of school governance. The cases discussed are generally limited to those decided during 1974 and reported in the General Digest on or before March 1, 1975. Because of its unusual significance,…

  10. The Influence of Tree Species on Subsurface Stormflow at the Hillslope Scale

    NASA Astrophysics Data System (ADS)

    Jost, G.; Weiler, M.

    2006-12-01

    value is less than one hour. The hillslope at the spruce stand produces between 23% and 28% runoff. However, the beech hillslope produces roughly twice as much. These experiments show that the interactions between tree species and soil in the vadose zone lead to different pore systems and thus different responses to subsurface stormflow. Beech with its deeper rooting systems and its higher biogenic activity (lower C/N ratio) creates a very effective preferential flow path system that leads to greater amounts of subsurface stormflow. Under high antecedent soil water storage, saturation excess overland flow is more likely to occur in soils under spruce with its smaller preferential flow system.

  11. Influence of Acidic and Alkaline Waste Solution Properties on Uranium Migration in Subsurface Sediments

    SciTech Connect

    Szecsody, James E.; Truex, Michael J.; Qafoku, Nikolla; Wellman, Dawn M.; Resch, Charles T.; Zhong, Lirong

    2013-08-01

    This study shows that acidic and alkaline wastes co-disposed with uranium into subsurface sediments has significant impact on changes in uranium retardation, concentration, and mass during downward migration. For uranium co-disposal with acidic wastes, significant rapid (i.e., hours) carbonate and slow (i.e., 100s of hours) clay dissolution resulted, releasing significant sediment-associated uranium, but the extent of uranium release and mobility change was controlled by the acid mass added relative to the sediment proton adsorption capacity. Mineral dissolution in acidic solutions (pH 2) resulted in a rapid (< 10 h) increase in aqueous carbonate (with Ca2+, Mg2+) and phosphate and a slow (100s of hours) increase in silica, Al3+, and K+, likely from 2:1 clay dissolution. Infiltration of uranium with a strong acid resulted in significant shallow uranium mineral dissolution and deeper uranium precipitation (likely as phosphates and carbonates) with downward uranium migration of three times greater mass at a faster velocity relative to uranium infiltration in pH neutral groundwater. In contrast, mineral dissolution in an alkaline environment (pH 13) resulted in a rapid (< 10 h) increase in carbonate, followed by a slow (10s to 100s of hours) increase in silica concentration, likely from montmorillonite, muscovite, and kaolinite dissolution. Infiltration of uranium with a strong base resulted in uranium-silicate precipitation (presumed Na-boltwoodite) but also desorption of natural uranium on the sediment due to the high ionic strength solution, or 60% greater mass with greater retardation compared with groundwater. Overall, these results show that acidic or alkaline co-contaminant disposal with uranium can result in complex depth- and time-dependent changes in uranium dissolution/precipitation reactions and uranium sorption, which alter the uranium migration mass, concentration, and velocity.

  12. Seasonal influence on sulfate reduction and zinc sequestration in subsurface treatment wetlands.

    PubMed

    Stein, Otto R; Borden-Stewart, Deborah J; Hook, Paul B; Jones, Warren L

    2007-08-01

    To characterize the effects of season, temperature, plant species, and chemical oxygen demand (COD) loading on sulfate reduction and metals removal in treatment wetlands we measured pore water redox potentials and concentrations of sulfate, sulfide, zinc and COD in subsurface wetland microcosms. Two batch incubations of 20 day duration were conducted in each of four seasons defined by temperature and daylight duration. Four treatments were compared: unplanted controls, Typha latifolia (broadleaf cattail), and Schoenoplectus acutus (hardstem bulrush), all at low COD loading (267 mg/L), plus bulrush at high COD loading (534 mg/L). Initial SO4-S and zinc concentrations were 67 and 24 mg/L, respectively. For all treatments, sulfate removal was least in winter (4 degrees C, plant dormancy) greatest in summer (24 degrees C, active plant growth) and intermediate in spring and fall (14 degrees C), but seasonal variation was greater in cattail, and especially, bulrush treatments. Redox measurements indicated that, in winter, plant-mediated oxygen transfer inhibited activity of sulfate reducing bacteria, exacerbating the reduction in sulfate removal due to temperature. Doubling the COD load in bulrush treatments increased sulfate removal by only 20-30% when averaged over all seasons and did not alter the basic pattern of seasonal variation, despite tempering the wintertime increase in redox potential. Seasonal and treatment effects on zinc removal were broadly consistent with sulfate removal and presumably reflected zinc-sulfide precipitation. Results strongly suggest that interactive effects of COD loading rate, temperature, season, and plant species control not only sulfate reduction and zinc sequestration, but also the balance of competition between various microbial consortia responsible for water treatment in constructed wetlands.

  13. Influence of acidic and alkaline waste solution properties on uranium migration in subsurface sediments

    NASA Astrophysics Data System (ADS)

    Szecsody, Jim E.; Truex, Mike J.; Qafoku, Nikolla P.; Wellman, Dawn M.; Resch, Tom; Zhong, Lirong

    2013-08-01

    This study shows that acidic and alkaline wastes co-disposed with uranium into subsurface sediments have significant impact on changes in uranium retardation, concentration, and mass during downward migration. For uranium co-disposal with acidic wastes, significant rapid (i.e., hours) carbonate and slow (i.e., 100 s of hours) clay dissolution resulted, releasing significant sediment-associated uranium, but the extent of uranium release and mobility change was controlled by the acid mass added relative to the sediment proton adsorption capacity. Mineral dissolution in acidic solutions (pH 2) resulted in a rapid (< 10 h) increase in aqueous carbonate (with Ca2 +, Mg2 +) and phosphate and a slow (100 s of hours) increase in silica, Al3 +, and K+, likely from 2:1 clay dissolution. Infiltration of uranium with a strong acid resulted in significant shallow uranium mineral dissolution and deeper uranium precipitation (likely as phosphates and carbonates) with downward uranium migration of three times greater mass at a faster velocity relative to uranium infiltration in pH neutral groundwater. In contrast, mineral dissolution in an alkaline environment (pH 13) resulted in a rapid (< 10 h) increase in carbonate, followed by a slow (10 s to 100 s of hours) increase in silica concentration, likely from montmorillonite, muscovite, and kaolinite dissolution. Infiltration of uranium with a strong base resulted in not only uranium-silicate precipitation (presumed Na-boltwoodite) but also desorption of natural uranium on the sediment due to the high ionic strength solution, or 60% greater mass with greater retardation compared with groundwater. Overall, these results show that acidic or alkaline co-contaminant disposal with uranium can result in complex depth- and time-dependent changes in uranium dissolution/precipitation reactions and uranium sorption, which alter the uranium migration mass, concentration, and velocity.

  14. 7 CFR 1210.362 - Influencing government action.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE WATERMELON RESEARCH AND PROMOTION PLAN Watermelon Research and Promotion Plan Miscellaneous § 1210.362 Influencing...

  15. 7 CFR 1210.362 - Influencing government action.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE WATERMELON RESEARCH AND PROMOTION PLAN Watermelon Research and Promotion Plan Miscellaneous § 1210.362 Influencing...

  16. Influence of dissimilatory metal reduction on fate of organic and metal contaminants in the subsurface

    NASA Astrophysics Data System (ADS)

    Lovley, Derek R.; Anderson, Robert T.

    Dissimilatory Fe(III)-reducing microorganisms have the ability to destroy organic contaminants under anaerobic conditions by oxidizing them to carbon dioxide. Some Fe(III)-reducing microorganisms can also reductively dechlorinate chlorinated contaminants. Fe(III)-reducing microorganisms can reduce a variety of contaminant metals and convert them from soluble forms to forms that are likely to be immobilized in the subsurface. Studies in petroleum-contaminated aquifers have demonstrated that Fe(III)-reducing microorganisms can be effective agents in removing aromatic hydrocarbons from groundwater under anaerobic conditions. Laboratory studies have demonstrated the potential for Fe(III)-reducing microorganisms to remove uranium from contaminated groundwaters. The activity of Fe(III)-reducing microorganisms can be stimulated in several ways to enhance organic contaminant oxidation and metal reduction. Molecular analyses in both field and laboratory studies have demonstrated that microorganisms of the genus Geobacter become dominant members of the microbial community when Fe(III)-reducing conditions develop as the result of organic contamination, or when Fe(III) reduction is artificially stimulated. These results suggest that further understanding of the ecophysiology of Geobacter species would aid in better prediction of the natural attenuation of organic contaminants under anaerobic conditions and in the design of strategies for the bioremediation of subsurface metal contamination. Des micro-organismes simulant la réduction du fer ont la capacité de détruire des polluants organiques dans des conditions anérobies en les oxydant en dioxyde de carbone. Certains micro-organismes réducteurs de fer peuvent aussi dé-chlorer par réduction des polluants chlorés. Des micro-organismes réducteurs de fer peuvent réduire tout un ensemble de métaux polluants et les faire passer de formes solubles à des formes qui sont susceptibles d'être immobilisées dans le milieu

  17. Computer modeling of pesticide fate at the hillslope scale. Influence of vegetated filter strips on surface runoff pesticides transfer and partitioning between surface and subsurface fluxes

    NASA Astrophysics Data System (ADS)

    Djabelkhir, K.; Carluer, N.; Lauvernet, C.

    2012-04-01

    In France, agriculture uses large quantities of fertilizer and pesticides. Water contamination by pesticides is highlighted by monitoring networks, at local and national levels. Control and reduction of contamination are major issues, for the protection of drinking water resources and aquatic ecosystems. Thus, understanding and quantifying the mechanisms involved in mobilization, transfer and dissipation of these substances can help to perform risk of water contamination diagnosis, and to estimate the effectiveness of corrective solutions. In this context, landscape elements, like buffer zones, can be an effective way to reduce diffuse contamination of pesticides carried by surface runoff. They protect the water ressources of the drift of the products applied to crops and contribute to the reduction of the transfer of pesticides in surface runoff from the plots to the river. We are interested in our study to the vegetative filter strips. The main objective of this thesis is to develop a model simulating the processes governing the transfer and dissipation of pesticides from plots to surface water, on surface and subsurface, along a slope. This will be done by taking into account the influence of vegetative filter strips between plots and rivers on the transfer, by changing the flow paths and retention time of these products via several mechanisms (infiltration, filtration of runoff -sedimentation of MES-, adsorption and degradation of products on the surface of the vegetative filter strips or infiltrated). Several models describing the mechanisms of transfer of water and solutes (sometimes) at a hillslope scale exist, in particular : POLA (Pinheiro and al., 1995), Openfluid (LISAH), J2000-JAMS (Krause and al., 2006), CatFlow (Zehe and al., 2000), tRIBS (Ivanov and al., 2004), Cathy 3D (Bixio and al., 2000) and CMF (Kraft and al., 2011). It was decided to choose a spatially distributed and object-oriented model, allowing to couple hydrological processes occuring

  18. The Growing Influence of the Government on the Affairs of the University. A Self Study.

    ERIC Educational Resources Information Center

    George Washington Univ., Washington, DC.

    A self-study conducted by George Washington University on the influence of the government on university affairs considered the following areas: (1) civil rights legislation and compliance; (2) legislation other than civil rights requiring compliance (e.g., occupational safety); (3) government program funding priorities; and (4) funds…

  19. Engaging school governance leaders to influence physical activity policies.

    PubMed

    Cox, Lindsey; Berends, Victoria; Sallis, James F; St John, Jessica Marie; McNeil, Betsy; Gonzalez, Martin; Agron, Peggy

    2011-01-01

    Most youth are not meeting physical activity guidelines, and schools are a key venue for providing physical activity. School districts can provide physical activity opportunities through the adoption, implementation, monitoring, and evaluation of policies. This paper reports results of a 2009 survey of California school governance leaders on the barriers and opportunities to providing school-based physical activity and strategies to promote adoption of evidence-based policies. California school board members (n = 339) completed an 83 item online survey about policy options, perceptions, and barriers to improving physical activity in schools. Board members' highest rated barriers to providing physical activity were budget concerns, limited time in a school day, and competing priorities. The key policy opportunities to increase physical activity were improving the quantity and quality of physical education, integrating physical activity throughout the school day, supporting active transportation to/from school, providing access to physical activity facilities during nonschool hours, and integrating physical activity into before/after school programs. Survey findings were used to develop policy resources and trainings for school governance leaders that provide a comprehensive approach to improving physical activity in schools.

  20. Deep subsurface microbial processes

    USGS Publications Warehouse

    Lovley, D.R.; Chapelle, F.H.

    1995-01-01

    Information on the microbiology of the deep subsurface is necessary in order to understand the factors controlling the rate and extent of the microbially catalyzed redox reactions that influence the geophysical properties of these environments. Furthermore, there is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by man's activities, and there is a need to predict the extent to which microbial activity may remediate such contamination. Metabolically active microorganisms can be recovered from a diversity of deep subsurface environments. The available evidence suggests that these microorganisms are responsible for catalyzing the oxidation of organic matter coupled to a variety of electron acceptors just as microorganisms do in surface sediments, but at much slower rates. The technical difficulties in aseptically sampling deep subsurface sediments and the fact that microbial processes in laboratory incubations of deep subsurface material often do not mimic in situ processes frequently necessitate that microbial activity in the deep subsurface be inferred through nonmicrobiological analyses of ground water. These approaches include measurements of dissolved H2, which can predict the predominant microbially catalyzed redox reactions in aquifers, as well as geochemical and groundwater flow modeling, which can be used to estimate the rates of microbial processes. Microorganisms recovered from the deep subsurface have the potential to affect the fate of toxic organics and inorganic contaminants in groundwater. Microbial activity also greatly influences 1 the chemistry of many pristine groundwaters and contributes to such phenomena as porosity development in carbonate aquifers, accumulation of undesirably high concentrations of dissolved iron, and production of methane and hydrogen sulfide. Although the last decade has seen a dramatic increase in interest in deep subsurface microbiology, in comparison with the study of

  1. Indications for solar influence on radon signal in the subsurface of Tenerife (Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Steinitz, G.; Martin-Luis, M. C.; Piatibratova, O.

    2015-05-01

    Radon at two locations in Tenerife is investigated. The MM-0 site is located in a bunker near Teide volcano. Daily radon (DR) signals are dominated by a 12-hour (S2) periodicity. Continuous wavelet transform (CWT) analysis of day-time and night-time series results in a day-night differentiation, which does not occur in the coeval temperature and pressure. This indicates that the radon system is directly affected by rotation of Earth around its axis, and not via the pressure and/or temperature pattern. San Fernando sites are in an underground gallery, located at 2.1 and 3 km from the entrance. Alpha and gamma time series show DR signals having an S1 and a strong S2 periodicity. Sidebands occur around the S1 periodicity. The lower sideband is close to 0.9972696 cycles per day (CPD; = sidereal frequency) and the upper sideband at a symmetric frequency above. They reflect a driver containing two waveforms having periodicities of rotation of Earth around its axis and around the Sun that influences radon in a non-linear fashion, leading to the sidebands around the S1 periodicity. Observation in Tenerife of sidebands and day-night phenomena substantiates the notion that the periodic components in the diurnal and annual frequency band of radon time series are due to the influence of a component in solar radiation.

  2. Influence of flow velocity on the removal of faecal coliforms in horizontal subsurface flow constructed wetland.

    PubMed

    Lohay, W S; Lyimo, T J; Njau, K N

    2012-01-01

    In order to determine the influence of flow velocity on the removal of faecal coliforms (FC) in constructed wetlands (CWs), removal rate constants of FC (k(FC)) were studied at various flow velocities (u). Membrane filtration technique was used during analysis. Values of k(FC) were determined using Reed's equation of pathogen removal; the results were compared with the plug flow equation. According to Reed's equation, k(FC) values ranged from 1.6 day⁻¹ at a velocity of 4 m/day to 34.5 day⁻¹ at a velocity of 42.9 m/day. The removal rates correlated positively with flow velocity (r = 0.84, p < 0.05). On assuming a plug flow equation, removal rates constants ranged from 0.77 to 11.69 day⁻¹; a more positive correlation (r = 0.93, p < 0.05) was observed. Optimum removal rate constants were observed for the velocity ranging 36 to 43 m/day. Generally, the increase of flow velocity improved FC removal rate constants: implying that pathogen removals are influenced by diffusion of the microorganisms into the biofilms on CW media. The velocity dependent approach together with the plug flow equation is therefore proposed for incorporation in the design of CW in a tropical climate where temperature variations are minor.

  3. Influence of Microbial Iron and Nitrate Reduction on Subsurface Iron Biogeochemistry and Contaminant Metal Mobilization

    SciTech Connect

    Flynn W. Picardal

    2002-04-10

    Although toxic metal and radionuclide contaminants can not be destroyed, their toxicity and mobility can be dramatically altered by microbial activity. In addition to toxic metals, many contaminated sites contain both iron-containing minerals and co-contaminants such as nitrate NO{sub 3}{sup -}. Successful implementation of metal and radionuclide bioremediation strategies in such environments requires an understanding of the complex microbial and geochemical interactions that influence the redox speciation and mobility of toxic metals. Our specific objectives have been to (1) determine the effect of iron oxide mineral reduction on the mobility of sorbed, representative toxic metals (Zn{sup 2+}), (2) study the biogeochemical interactions that may occur during microbial reduction of NO{sub 3}{sup -} and iron oxide minerals, and (3) evaluate the kinetics of NO{sub 3}{sup -}-dependent, microbial oxidation of ferrous iron (Fe{sup 2+}).

  4. Influences of specific ions in groundwater on concrete degradation in subsurface engineered barrier system.

    PubMed

    Lin, Wen-Sheng; Liu, Chen-Wuing; Li, Ming-Hsu

    2016-01-01

    Many disposal concepts currently show that concrete is an effective confinement material used in engineered barrier systems (EBS) at a number of low-level radioactive waste (LLW) disposal sites. Cement-based materials have properties for the encapsulation, isolation, or retardation of a variety of hazardous contaminants. The reactive chemical transport model of HYDROGEOCHEM 5.0 was applied to simulate the effect of hydrogeochemical processes on concrete barrier degradation in an EBS which has been proposed to use in the LLW disposal site in Taiwan. The simulated results indicated that the main processes that are responsible for concrete degradation are the species induced from hydrogen ion, sulfate, and chloride. The EBS with the side ditch drainage system effectively discharges the infiltrated water and lowers the solute concentrations that may induce concrete degradation. The redox processes markedly influence the formations of the degradation materials. The reductive environment in the EBS reduces the formation of ettringite in concrete degradation processes. Moreover, the chemical conditions in the concrete barriers maintain an alkaline condition after 300 years in the proposed LLW repository. This study provides a detailed picture of the long-term evolution of the hydrogeochemical environment in the proposed LLW disposal site in Taiwan.

  5. Site Recommendation Subsurface Layout

    SciTech Connect

    C.L. Linden

    2000-06-28

    The purpose of this analysis is to develop a Subsurface Facility layout that is capable of accommodating the statutory capacity of 70,000 metric tons of uranium (MTU), as well as an option to expand the inventory capacity, if authorized, to 97,000 MTU. The layout configuration also requires a degree of flexibility to accommodate potential changes in site conditions or program requirements. The objective of this analysis is to provide a conceptual design of the Subsurface Facility sufficient to support the development of the Subsurface Facility System Description Document (CRWMS M&O 2000e) and the ''Emplacement Drift System Description Document'' (CRWMS M&O 2000i). As well, this analysis provides input to the Site Recommendation Consideration Report. The scope of this analysis includes: (1) Evaluation of the existing facilities and their integration into the Subsurface Facility design. (2) Identification and incorporation of factors influencing Subsurface Facility design, such as geological constraints, thermal loading, constructibility, subsurface ventilation, drainage control, radiological considerations, and the Test and Evaluation Facilities. (3) Development of a layout showing an available area in the primary area sufficient to support both the waste inventories and individual layouts showing the emplacement area required for 70,000 MTU and, if authorized, 97,000 MTU.

  6. Influence of Assimilation of Subsurface Temperature Measurements on Simulations of Equatorial Undercurrent and South Equatorial Current Along the Pacific Equator

    NASA Technical Reports Server (NTRS)

    Halpern, David; Leetmaan, Ants; Reynolds, Richard W.; Ji, Ming

    1997-01-01

    Equatorial Pacific current and temperature fields were simulated with and without assimilation of subsurface temperature measurements for April 1992 - March 1995, and compared with moored bouy and research vessel current measurements.

  7. Influence of Assimilation of Subsurface Temperature Measurements on Simulations of Equatorial Undercurrent and South Equatorial Current Along the Pacific Equator

    NASA Technical Reports Server (NTRS)

    Halpern, David; Leetmaan, Ants; Reynolds, Richard W.; Ji, Ming

    1997-01-01

    Equatorial Pacific current and temperature fields were simulated with and without assimilation of subsurface temperature measurements for April 1992 - March 1995, and compared with moored bouy and research vessel current measurements.

  8. Sociopolitical Influences on Federal Government Funding of Gifted and Talented and Bilingual Education Programs.

    ERIC Educational Resources Information Center

    Casanova, Ursula; Chavez, Sheila

    1992-01-01

    Examines the influence of various sociopolitical factors on government policies in two federal programs, those for the gifted and talented and those for bilingual education. Traces the evolution of these programs and compares their backgrounds to determine the influences shaping federal funding and program implementation. (GLR)

  9. Three essays in corporate finance: Examining the influence of government ownership and evaluating crude oil arbitrage

    NASA Astrophysics Data System (ADS)

    Holland, Kateryna

    The aim of this dissertation is twofold: first, to evaluate how governments influence firms in which they invest (chapters one and two), and second, to examine arbitrage in the crude oil market by investigating the relationship between crude oil inventories, physical prices, and financial prices (chapter three). In the first chapter (The Wealth Effects of Government Investment in Publicly Traded Firms), I study how government share ownership affects shareholder wealth. I find that government investments with higher likelihood of political interference have a negative influence on shareholder wealth, while the opposite is true for government investments with economic objectives. In the second chapter (Government Ownership and the Cost of Debt: Evidence form Government Investment in Publicly Traded Firms), I investigate how government share ownership affects the cost of debt of publicly traded firms. I find that government ownership generally leads to a higher cost of debt, except for times of economic and firm distress, when the value of the implicit government guarantee is associated with a reduction in the cost of debt. In the third chapter (Financial Trading, Spot Oil Prices, and Inventory: Evidence from the U.S. Crude Oil Market), I confirm the existence of an active cash and carry market in crude oil in Cushing, OK, the main U.S. crude oil futures settlement location. In other words, crude oil inventories in Cushing, but not in any other U.S. crude oil storage locations, are explained by the spread between the financial and the physical price of oil in addition to operational factors.

  10. Switching between hydrophobic and wettable conditions in soil: experiments to assess the influence of cracks, roots and subsurface drainage impedance

    NASA Astrophysics Data System (ADS)

    Urbanek, E.; Walsh, R. P. D.; Shakesby, R. A.

    2012-04-01

    Although much is known about soil hydrophobicity, assessments of the overall hydrological and erosional significance of the soil property in areas affected by it are greatly hampered by a lack of knowledge on switching between hydrophobic and hydrophilic states. This arises mainly because of (1) the destructive nature of methods of assessing hydrophobicity, (2) its often high local spatial variability and (3) difficulties of relating hydrophobicity results to meaningful soil moisture values. Also, very little is known about the influence which cracks and holes through hydrophobic soil and the presence or absence of subsurface impeding layers have on the 3D pattern and speed of hydrophobicity change during wetting and drying cycles. These issues form the focus of the present paper, which was carried out as part of the EU DESIRE Project. A laboratory experimental approach was adopted. Three different soils of equal initial hydrophibicity class when dry (18 % MED), but of contrasting texture and total carbon content, were investigated: (1) from the scrub-covered (dominated by Erica umbellata, Calluna vulgaris and Pterospartum tridentatum) Vale Torto catchment in Gois municipality, central Portugal (an area where the impacts of prescribed fire were being assessed); (2) soil around a Chamaecyparis lawsonia tree in South Wales; and (3) a vegetated coastal sand-dune location at Nicholaston, Gower Peninsula, South Wales. For the experiments, 106 samples of sieved (< 2 mm), dried soil were placed to a depth of 10 cm in standardized transparent pots (16.5 cm high, top diameter 16 cm, basal diameter 11 cm). Equal numbers of samples were prepared with either (i) five simulated holes, (ii) two simulated linear cracks (in both cases extending downwards to the sample base) and (iii) control soil samples without cracks or holes). Samples were also either (i) sealed at the base to create subsurface impeded drainage or (ii) provided with unimpeded basal drainage by insertion of

  11. 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.

  12. Subsurface band application of poultry litter and its influence on Phosphorus concentration and retention after runoff from permanent pastures

    USDA-ARS?s Scientific Manuscript database

    Excessive P loss from agricultural fields has been identified as a major cause of eutrophication to river, lakes, and streams. To minimize and mitigate P loss from poultry litter (PL) applications, new technology is being developed for subsurface band application of litter below the soil surface. Th...

  13. Subsurface application of poultry litter and its influence on nutrient losses in runoff water from permanent pastures

    USDA-ARS?s Scientific Manuscript database

    Environmental pressure to reduce nutrient losses from agricultural fields has increased in recent years. To abate this nutrient loss to the environment, better management practices and new technologies need to be developed. Thus, research was conducted to evaluate if subsurface banding poultry lit...

  14. Emerging organic contaminant removal depending on primary treatment and operational strategy in horizontal subsurface flow constructed wetlands: influence of redox.

    PubMed

    Avila, Cristina; Reyes, Carolina; Bayona, Josep María; García, Joan

    2013-01-01

    This study aimed at assessing the influence of primary treatment (hydrolytic upflow sludge blanket (HUSB) reactor vs. conventional settling) and operational strategy (alternation of saturated/unsaturated phases vs. permanently saturated) on the removal of various emerging organic contaminants (i.e. ibuprofen, diclofenac, acetaminophen, tonalide, oxybenzone, bisphenol A) in horizontal subsurface flow constructed wetlands. For that purpose, a continuous injection experiment was carried out in an experimental treatment plant for 26 days. The plant had 3 treatment lines: a control line (settler-wetland permanently saturated), a batch line (settler-wetland operated with saturate/unsaturated phases) and an anaerobic line (HUSB reactor-wetland permanently saturated). In each line, wetlands had a surface area of 2.95 m(2), a water depth of 25 cm and a granular medium D(60) = 7.3 mm, and were planted with common reed. During the study period the wetlands were operated at a hydraulic and organic load of 25 mm/d and about 4.7 g BOD/m(2)d, respectively. The injection experiment delivered very robust results that show how the occurrence of higher redox potentials within the wetland bed promotes the elimination of conventional quality parameters as well as emerging microcontaminants. Overall, removal efficiencies were always greater for the batch line than for the control and anaerobic lines, and to this respect statistically significantly differences were found for ibuprofen, diclofenac, oxybenzone and bisphenol A. As an example, ibuprofen, whose major removal mechanism has been reported to be biodegradation under aerobic conditions, showed a higher removal in the batch line (85%) than in the control (63%) and anaerobic (52%) lines. Bisphenol A showed also a great dependence on the redox status of the wetlands, finding an 89% removal rate for the batch line, as opposed to the control and anaerobic lines (79 and 65%, respectively). Furthermore, diclofenac showed a greater

  15. Influence of environmental parameters on the concentration of subsurface dissolved methane in two hydroelectric power plants in Brazil

    NASA Astrophysics Data System (ADS)

    Silva, M. G.; Marani, L.; Alvala, P. C.

    2013-12-01

    Methane (CH4) is a trace gas in the atmosphere of great importance for atmospheric chemistry as one of the main greenhouse gases. There are different sources with the largest individual production associated with the degradation of organic matter submerged in flooded areas. The amount of dissolved methane that reaches the surface depends on the production in the sediments and consumption in the water column. Both processes are associated with microbial activity and consequently dependent on the physico-chemical environmental conditions. The construction of hydroelectric dams cause flooding of areas near the river that can change the characteristics of the environment and cause changes in subsurface methane concentration. In this work, we studied two hydroelectric plants located in Brazil: Batalha (17°20'39.52"S, 47°29'34.29"W), under construction when the samples were take, and Itaipu (25°24'45.00"S, 54°35'39.00"W) which has been floated over 30 years ago. The water samples to determine dissolved methane were collected approximately 5 cm near the surface. In each collection point was measured depth, water temperature, pH and redox potential. The range of dissolved methane between the two dams was similar: 0.07-10.33 μg/l (Batalha) and 0.15-10.93 μg/l (Itaipu). However, the Batalha's average (4.04 × 3.43 μg/l; median = 3.66 μg/l) was higher than that observed in Itaipu (2.15 × 1.59 μg/l; median = 2.53 μg/l). The influence of environmental parameters on the concentration of dissolved methane was evaluated by multivariate statistical techniques (Principal Component Analysis - PCA). All of the parameters had some correlation with dissolved methane, however, the greatest contribution in Batalha was associated with pH while in Itaipu was the depth. The pH variation of the various points studied in Batalha may be associated with periods of drought and flooding of the river and hence the incorporation of organic matter in the environment. The organisms

  16. Subsurface application of poultry litter and its influence on nutrient losses in runoff water from permanent pastures.

    PubMed

    Watts, D B; Way, T R; Torbert, H A

    2011-01-01

    Environmental pressure to reduce nutrient losses from agricultural fields has increased in recent years. To abate this nutrient loss to the environment, better management practices and new technologies need to be developed. Thus, research was conducted to evaluate if subsurface banding poultry litter (PL) would reduce nitrogen (N) and phosphorus (P) loss in surface water runoff using a four-row prototype implement. Rainfall simulations were conducted to create a 40-min runoff event in an established bermudagrass (Cynodon dactylon L.) pasture on soil types common to the Coastal Plain and Piedmont regions. The Coastal Plain soil type was a Marvyn loamy sand (fine-loamy, kaolinitic, thermic Typic Kanhapludults) and the Piedmont soil type was a Hard Labor loamy sand (fine, kaolinitic, thermic Oxyaquic Kanhapludults). Treatments consisted of surface- and subsurface-applied PL at a rate of 9 Mg ha(-1), surface broadcast-applied commercial fertilizer (CF; urea and triple superphosphate blend) at the equivalent N (330 kg N ha(-1)) and P (315 kg N ha(-1)) content of PL, and a nonfertilized control. The greatest loss for inorganic N, total N, dissolved reactive P (DRP), and total P occurred with the surface broadcast treatments, with CF contributing to the greatest loss. Nutrient losses from the subsurface banded treatment reduced N and P in surface water runoff to levels of the control. Subsurface banding of PL reduced concentrations of inorganic N 91%, total N 90%, DRP 86%, and total P 86% in runoff water compared with surface broadcasted PL. These results show that subsurface band-applied PL can greatly reduce the impact of N and P loss to the environment compared with conventional surface-applied PL and CF practices.

  17. Agency Governance and Enforcement: The Influence of Mission on Environmental Decisionmaking

    ERIC Educational Resources Information Center

    Firestone, Jeremy

    2002-01-01

    Administrative agencies seeking to impose sanctions for regulatory violations can handle matters internally or through civil or criminal courts. Organizational culture, legal constraints, and political and private actors may influence governance and hence choice of enforcement venue. An enforcement behavior model is constructed and tested…

  18. Assessment of Groups Influence on Management Style as Related to University Governance

    ERIC Educational Resources Information Center

    Irtwange, S. V.; Orsaah, S.

    2010-01-01

    The study was undertaken with the objective of assessing groups influence on management style as related to University governance with University of Agriculture, Makurdi as a case study from academic staff perspective. The management style of the Vice Chancellor of the University of Agriculture, Makurdi between the period September 3, 1996 to…

  19. Factors Influencing the Design, Establishment, Administration, and Governance of Correctional Education for Females

    ERIC Educational Resources Information Center

    Ellis, Johnica; McFadden, Cheryl; Colaric, Susan

    2008-01-01

    This article summarizes the results of a study conducted to investigate factors influencing the organizational design, establishment, administration, and governance of correctional education for females. The research involved interviews with correctional and community college administrators and practitioners representing North Carolina female…

  20. Assessment of Groups Influence on Management Style as Related to University Governance

    ERIC Educational Resources Information Center

    Irtwange, S. V.; Orsaah, S.

    2010-01-01

    The study was undertaken with the objective of assessing groups influence on management style as related to University governance with University of Agriculture, Makurdi as a case study from academic staff perspective. The management style of the Vice Chancellor of the University of Agriculture, Makurdi between the period September 3, 1996 to…

  1. Agency Governance and Enforcement: The Influence of Mission on Environmental Decisionmaking

    ERIC Educational Resources Information Center

    Firestone, Jeremy

    2002-01-01

    Administrative agencies seeking to impose sanctions for regulatory violations can handle matters internally or through civil or criminal courts. Organizational culture, legal constraints, and political and private actors may influence governance and hence choice of enforcement venue. An enforcement behavior model is constructed and tested…

  2. The Uses of Political Science: The Allocation of Policy Influence among Levels of Government.

    ERIC Educational Resources Information Center

    Stonecash, Jeff

    This paper discusses the allocation of policy influences at the national, state, and local levels of government. A theory of what causes a change from a decentralized to a more centralized system is developed and whether and how such a theory of change is related to a theory of the origins of a federal system is explored. The author presents…

  3. Factors Influencing the Design, Establishment, Administration, and Governance of Correctional Education for Females

    ERIC Educational Resources Information Center

    Ellis, Johnica; McFadden, Cheryl; Colaric, Susan

    2008-01-01

    This article summarizes the results of a study conducted to investigate factors influencing the organizational design, establishment, administration, and governance of correctional education for females. The research involved interviews with correctional and community college administrators and practitioners representing North Carolina female…

  4. Professional-Patron Influence on Site-Based Governance Councils: A Confounding Case Study.

    ERIC Educational Resources Information Center

    Malen, Betty; Ogawa, Rodney T.

    1988-01-01

    A case study of site-based governance councils in Salt Lake City (Utah) is described. The study was a test of whether building-based councils actually enable teachers and parents to exert substantial influence on school policy. The reason why research findings did not fit expectations is discussed. (SLD)

  5. The influence of droplet size and biodegradation on the transport of subsurface oil droplets during the Deepwater Horizon spill: a model sensitivity study

    NASA Astrophysics Data System (ADS)

    North, Elizabeth W.; Adams, E. Eric; Thessen, Anne E.; Schlag, Zachary; He, Ruoying; Socolofsky, Scott A.; Masutani, Stephen M.; Peckham, Scott D.

    2015-02-01

    A better understanding of oil droplet formation, degradation, and dispersal in deep waters is needed to enhance prediction of the fate and transport of subsurface oil spills. This research evaluates the influence of initial droplet size and rates of biodegradation on the subsurface transport of oil droplets, specifically those from the Deepwater Horizon oil spill. A three-dimensional coupled model was employed with components that included analytical multiphase plume, hydrodynamic and Lagrangian models. Oil droplet biodegradation was simulated based on first order decay rates of alkanes. The initial diameter of droplets (10-300 μm) spanned a range of sizes expected from dispersant-treated oil. Results indicate that model predictions are sensitive to biodegradation processes, with depth distributions deepening by hundreds of meters, horizontal distributions decreasing by hundreds to thousands of kilometers, and mass decreasing by 92-99% when biodegradation is applied compared to simulations without biodegradation. In addition, there are two- to four-fold changes in the area of the seafloor contacted by oil droplets among scenarios with different biodegradation rates. The spatial distributions of hydrocarbons predicted by the model with biodegradation are similar to those observed in the sediment and water column, although the model predicts hydrocarbons to the northeast and east of the well where no observations were made. This study indicates that improvement in knowledge of droplet sizes and biodegradation processes is important for accurate prediction of subsurface oil spills.

  6. Temporal variation of the shallow subsurface at the Aquistore CO2 storage site associated with environmental influences using a continuous and controlled seismic source

    NASA Astrophysics Data System (ADS)

    Ikeda, Tatsunori; Tsuji, Takeshi; Takanashi, Mamoru; Kurosawa, Isao; Nakatsukasa, Masashi; Kato, Ayato; Worth, Kyle; White, Don; Roberts, Brian

    2017-04-01

    The development of reliable systems for monitoring injected CO2 is essential in carbon capture and storage projects. We applied time-lapse surface wave analysis to measure temporal variations of the shallow subsurface among 11 periods (0.2-21.6 days) of continuous seismic data acquired from 2014 to 2016 at the Aquistore CO2 storage site in Canada. We focused on monitoring environmental influences on shallow seismic velocity, which are unrelated to CO2 injection into deep reservoirs. A continuous, controlled seismic source system called Accurately Controlled Routinely Operated Signal System was used to enhance the temporal resolution and source repeatability. Observed phase velocities were clearly higher in winter than in warmer seasons. The seasonal variation could be reproduced by an increase in the shallow S wave velocity during winter associated with the greater extent of freezing of partially saturated rock. We also observed gradual increases or decreases in phase velocities as the seasons changed, which could be related to gradual freezing or melting of ice. Our monitoring system thus could be effective for monitoring temporal variations of the shallow subsurface associated with the degree of freezing. Furthermore, the high temporal stability of our monitoring approach in warm seasons may make it possible to immediately identify CO2 leakage in the shallow subsurface.

  7. Modeling the influence of exopolymeric substances (EPS) extracted from Pseudomonas bacteria on chromium (III) sorption and transport in heterogeneous subsurface soils

    NASA Astrophysics Data System (ADS)

    Kantar, C.; Demiray, H.; Koleli, N.; Mercan, N.

    2009-04-01

    In situ remediation of soils contaminated with Cr(VI) is usually accomplished through microbial reduction of Cr(VI) to Cr(III) by soil microorganisms including Pseudomonas bacteria. Cr(VI) is a toxic substance that may stimulate the production of exopolymeric substances (EPS) by soil bacteria. Natural organic ligands such as EPS may have a pronounced impact on Cr(III) solubility, sorption, transport and bioavailability in subsurface systems. In this study, laboratory sorption and column experiments were performed to investigate the influence of exopolymeric substances (EPS) extracted from Pseudomonas aeruginosa P16, Pseudomonas putida P18 and Pseudomonas stutzeri P40 on chromium (III) sorption and transport in heterogeneous subsurface soils. The results from laboratory experiments indicate that microbial EPS enhanced Cr(III) solubility, which, in turn, led to an increase in Cr(III) transport through columns packed with subsurface soils under slightly acidic to alkaline pH conditions. A reactive transport code that includes a semi-empirical surface complexation model (SCM) to describe chemical processes e.g., sorption was used to simulate bench-scale column data for Cr(III) transport in the presence of EPS. Our transport simulations suggest that for an accurate simulation of Cr(III) transport in the presence of microbial EPS, the following processes and/or interactions need to be explicitly considered: 1) Cr(III)-EPS interactions; 2) binary soil/Cr and soil/EPS surface complexes; and 3) ternary soil/Cr/EPS complexes.

  8. Testing a model of county government influence on health care safety-nets.

    PubMed

    Knepper, Hillary

    2012-01-01

    In the United States, health care is not equitably distributed. As indicated in the literature, age, income, and other socio-economic indicators contribute to substantial differences in the variety and scope of health services. The 2010 Affordable Care Act illustrates the United States' effort to bring balance and equity to the health care system. In the meantime, county governments are struggling with rising health care costs on their budgets (Eaton, 2009; Phaup, 2009; Clark, 2003), particularly health care for low-income residents (Benton, Byers, Cigler, Klase, Menzel, Salant, Streib, Svara, & Waugh, 2008). However, as learned in this study, county governments across the country continue to address the health care needs of uninsured and underinsured citizens through participation in health care safety nets. This research identifies possible county government influences on health care safety-nets. This study analyzed 123 responses from county government administrators and elected officials along with secondary data from the U.S. Census Bureau and the International City/County Manager Association using a variety of statistical techniques, culminating in structural equation modeling. These analyses provided reasonable explanation for the variation among the variables leading to network performance improvement in meeting the health care needs of uninsured and underinsured people as well as the significant influence of county government involvement.

  9. Limiting the Influence of Pharmaceutical Industry Gifts on Physicians: Self-Regulation or Government Intervention?

    PubMed Central

    2009-01-01

    Concerns over the influence of pharmaceutical gifts on physicians have surged in recent years. This has prompted wide ranging legislative proposals in numerous states and in the federal government as well as stepped up efforts at self-regulation by the pharmaceutical industry and the medical profession. Policymakers face the decision of whether to defer to self-regulation or support government intervention. This commentary describes efforts at self-regulation by the pharmaceutical industry and the medical profession. The author examines and critiques the wide ranging legislative strategies pursued to limit the influence of pharmaceutical gifts on physicians and concludes with suggestions for policymakers and the profession to limit influence and preserve public trust. PMID:19756874

  10. Subsurface geometry of the San Andreas-Calaveras fault junction: influence of serpentinite and the Coast Range Ophiolite

    USGS Publications Warehouse

    Watt, Janet Tilden; Ponce, David A.; Graymer, Russell W.; Jachens, Robert C.; Simpson, Robert W.

    2014-01-01

    While an enormous amount of research has been focused on trying to understand the geologic history and neotectonics of the San Andreas-Calaveras fault (SAF-CF) junction, fundamental questions concerning fault geometry and mechanisms for slip transfer through the junction remain. We use potential-field, geologic, geodetic, and seismicity data to investigate the 3-D geologic framework of the SAF-CF junction and identify potential slip-transferring structures within the junction. Geophysical evidence suggests that the San Andreas and Calaveras fault zones dip away from each other within the northern portion of the junction, bounding a triangular-shaped wedge of crust in cross section. This wedge changes shape to the south as fault geometries change and fault activity shifts between fault strands, particularly along the Calaveras fault zone (CFZ). Potential-field modeling and relocated seismicity suggest that the Paicines and San Benito strands of the CFZ dip 65° to 70° NE and form the southwest boundary of a folded 1 to 3 km thick tabular body of Coast Range Ophiolite (CRO) within the Vallecitos syncline. We identify and characterize two steeply dipping, seismically active cross structures within the junction that are associated with serpentinite in the subsurface. The architecture of the SAF-CF junction presented in this study may help explain fault-normal motions currently observed in geodetic data and help constrain the seismic hazard. The abundance of serpentinite and related CRO in the subsurface is a significant discovery that not only helps constrain the geometry of structures but may also help explain fault behavior and the tectonic evolution of the SAF-CF junction.

  11. Stochastic and Deterministic Assembly Processes in Subsurface Microbial Communities

    SciTech Connect

    Stegen, James C.; Lin, Xueju; Konopka, Allan; Fredrickson, Jim K.

    2012-03-29

    A major goal of microbial community ecology is to understand the forces that structure community composition. Deterministic selection by specific environmental factors is sometimes important, but in other cases stochastic or ecologically neutral processes dominate. Lacking is a unified conceptual framework aiming to understand why deterministic processes dominate in some contexts but not others. Here we work towards such a framework. By testing predictions derived from general ecological theory we aim to uncover factors that govern the relative influences of deterministic and stochastic processes. We couple spatiotemporal data on subsurface microbial communities and environmental parameters with metrics and null models of within and between community phylogenetic composition. Testing for phylogenetic signal in organismal niches showed that more closely related taxa have more similar habitat associations. Community phylogenetic analyses further showed that ecologically similar taxa coexist to a greater degree than expected by chance. Environmental filtering thus deterministically governs subsurface microbial community composition. More importantly, the influence of deterministic environmental filtering relative to stochastic factors was maximized at both ends of an environmental variation gradient. A stronger role of stochastic factors was, however, supported through analyses of phylogenetic temporal turnover. While phylogenetic turnover was on average faster than expected, most pairwise comparisons were not themselves significantly non-random. The relative influence of deterministic environmental filtering over community dynamics was elevated, however, in the most temporally and spatially variable environments. Our results point to general rules governing the relative influences of stochastic and deterministic processes across micro- and macro-organisms.

  12. Increasing a Community College Governing Board's Engagement in Accountability for Student Success: What Are the Principal Influences?

    ERIC Educational Resources Information Center

    Welsh, Linda Susan Anderson

    2010-01-01

    Understanding the factors that influence a community college governing board to increase its engagement in accountability for student success was the purpose of this grounded theory case study. A further aim was to develop a model that described how these factors interact. A highly engaged community college governing board, as defined by a focus,…

  13. Increasing a Community College Governing Board's Engagement in Accountability for Student Success: What Are the Principal Influences?

    ERIC Educational Resources Information Center

    Welsh, Linda Susan Anderson

    2010-01-01

    Understanding the factors that influence a community college governing board to increase its engagement in accountability for student success was the purpose of this grounded theory case study. A further aim was to develop a model that described how these factors interact. A highly engaged community college governing board, as defined by a focus,…

  14. Influence of surface and subsurface tillage on soil physical properties and soil/plant relationships of planted loblolly pine

    SciTech Connect

    D. L. Kelting; H. L. Allen

    2000-05-01

    Soil tillage can improve tree survival and growth by reducing competing vegetation, increasing nutrient availability, improving planting quality, and improving soil physical properties. The authors conducted a tillage study with competition control and nutrient amendments to isolate the physical effects of tillage on tree growth. The objectives of this study were to understand: (1) how tillage affects soil physical properties; (2) the relationships between these properties and root growth; (3) linkages between root growth response and aboveground growth; and (4) tillage effects on aboveground growth. Four replicates of a 2x2 factorial combination of surface (disking) and subsurface (subsoiling) were installed on a well-drained, clay-textured subsoil, soil located on the Piedmont of North Carolina. Disking improved soil physical properties (reduced bulk density and increased aeration porosity) in the surface 20-cm of soil. Subsoiling improved soil physical properties at all depths in the planting row, with improvements still noted at 60-cm from the planting row in the surface 10-cm of soil. Rooting patterns followed the changes in soil physical properties. Despite improvements in soil physical properties and changes in rooting patterns, aboveground tree growth was not affected by tillage. The results of this study point to the need for better diagnostics for identifying sites were tillage is appropriate in situations where fertilization and vegetation control are planned. Potential factors to consider are presence and abundance of old root channels, soil shrink/swell capacity, soil structure, presence and depth to root restricting layers, and historical precipitation records.

  15. Influence of vegetation and substrate on the removal and transformation of dissolved organic matter in horizontal subsurface-flow constructed wetlands.

    PubMed

    Li, Jianbo; Wen, Yue; Zhou, Qi; Xingjie, Zhao; Li, Xie; Yang, Silu; Lin, Tao

    2008-07-01

    The fate of dissolved organic matter (DOM) during horizontal subsurface-flow constructed wetlands (HSSF CWs) was examined. In several studies it had been demonstrated that factors such as vegetation and substrates type affected the treatment efficiency of DOM, while very few studies discerned their influence on the transformations of DOM. Thus three pilot-scale HSSF CWs, i.e. reed (Phragmites australis)/gravel bed (W1), hybrid vegetation{cattail (Typha latifolia), bulrush (Scirpus validus), reed}/gravel bed (W2) and reed/hybrid substrates bed (gravel, zeolite, slag) (W3), were designed, and were operated continuously to investigate soluble COD (SCOD) removal and DOM transformations affected by vegetation and substrate type, and to explore the correlation between SCOD and biodiversity. The results showed that cattail and bulrush contributed to higher SCOD removal than common reed, and that gravel, zeolite and slag did not show significant influence on SCOD removal. The composition of the dissolved organic carbon (DOC) could undergo a considerable shift in composition due to metabolism and senescence from plant and microorganism. Nonlabile aromatic hydrocarbons and alkyl hydrocarbons in the effluent were a significant portion compared with labile alcoholic and alkene in the influent. It was also observed that the type of vegetation and substrate had great influence on the structure of bacteria, and the Shannon-Wiener Index increased linearly with the decrease of SCOD concentration along water flow in W2 and W3 (R2=0.96).

  16. Subsurface environment database for application of ground heat exchanger system

    NASA Astrophysics Data System (ADS)

    Hamamoto, H.; Hachinohe, S.; Shiraishi, H.; Takashi, I.; Sasaka, K.; Miyakoshi, A.; Goto, S.

    2010-12-01

    Ground heat exchanger system is economical and environmentally friendly technology and widely used in Europe and North America, while it is rarely used in Japan. One of the causes is relatively complex topography and geological structure in Japan in comparison with those in Europe and North America. Complex structures produce regional differences in subsurface thermal properties and temperature structure, leading to regional variation in efficiency of heat exchanger system. It is thus important to evaluate available subsurface heat energy through thermal response tests and/or numerical simulation and to design appropriate systems (depth and number of boreholes for heat exchange). Information on subsurface environment in target areas is necessary for evaluation of potential subsurface heat energy, but little information has been published. Center for Environmental Science in Saitama is a research institute established by a local government, Saitama prefecture, which is located on the north of Tokyo and has a population of over seven million. We have been collecting various subsurface environmental data in Saitama (e.g., lithological column data on over 10,000 boreholes). We have compiled the accumulated data and obtained new data (geological information, subsurface temperature distribution, and hydrogeological properties) to construct a database for application of ground heat exchanger systems in Saitama. It is important to estimate demand for heat energy in the target areas as well as available subsurface heat energy. We therefore compile meteorological data (air temperature and solar radiation) necessary for estimation for the demand and investigate regional variation in meteorological condition. We intend to disclose the database and research products using web GIS (geographic information system) in the future. It will assist spread of ground heat exchanger systems in the target areas. Investigation methods of subsurface environment survey and database

  17. Catchment-scale stream temperature response to land disturbance by wildfire governed by surface-subsurface energy exchange and atmospheric controls

    NASA Astrophysics Data System (ADS)

    Wagner, Michael J.; Bladon, Kevin D.; Silins, Uldis; Williams, Chris H. S.; Martens, Amanda M.; Boon, Sarah; MacDonald, Ryan J.; Stone, Micheal; Emelko, Monica B.; Anderson, Axel

    2014-09-01

    In 2003, the Lost Creek wildfire severely burned 21,000 hectares of forest on the eastern slopes of the Canadian Rocky Mountains. Seven headwater catchments with varying levels of disturbance (burned, post-fire salvage logged, and unburned) were instrumented as part of the Southern Rockies Watershed Project to measure streamflow, stream temperature, and meteorological conditions. From 2004 to 2010 mean annual stream temperature (Ts) was elevated 0.8-2.1 °C in the burned and post-fire salvage logged streams compared to the unburned streams. Mean daily maximum Ts was 1.0-3.0 °C warmer and mean daily minimum Ts was 0.9-2.8 °C warmer in the burned and post-fire salvage logged streams compared to the unburned catchments. The effects of wildfire on the thermal regime of the burned catchments were persistent and trend analysis showed no apparent recovery during the study period. Temporal patterns of Ts were strongly associated with seasonal variability of surface and groundwater interactions and air temperature. Advective heat fluxes between groundwater and surface water were likely the dominant controls on Ts, though the strength of these advective controls varied among catchments highlighting the importance of simultaneous catchment-scale and process-focused research to better elucidate the physical drivers influencing Ts response to disturbance.

  18. Shake the Helping Hand: Tips on How Independent Schools Can Influence Local and State Government Policy.

    ERIC Educational Resources Information Center

    Corkran, John R.

    1980-01-01

    State or local governments are seen as helping hands for independent schools. In the state or local governments funding programs are available and issues of government regulation, tax exemptions, and civil rights are extensively debated. Some suggestions for developing good government relations are provided. (MLW)

  19. Integrating remote sensing and subsurface geological data to characterize a tidally-influenced paleodrainage from the mid-late Holocene succession of the Po Delta Plain (Italy)

    NASA Astrophysics Data System (ADS)

    Giacomelli, Serena; Rossi, Veronica; Amorosi, Alessandro; Bruno, Luigi; Campo, Bruno; Ciampalini, Andrea; Civa, Andrea; de Souza Filho, Roberto Carlos; Sgavetti, Maria

    2017-04-01

    A tidally-influenced, mid-late Holocene paleodrainage system from the Po Delta Plain (N Adriatic Sea, Italy) is reconstructed coupling remote sensing (RS) and subsurface geological data. Optical satellite images, DTM LiDAR, soil reflectance spectral features and core stratigraphy were combined in a GIS environment following a fully integrated methodological approach. The stratigraphic significance of RS-derived data (traces) was defined in terms of both depositional facies and depth, furnishing new insights on the role of RS in reconstructing the recent evolution of paleodrainages in coastal-deltaic settings. Sixteen images from Landsat 7 ETM+ (Enhanced Thematic Mapper Plus), Landsat 8 OLI (Operational Land Imager), Sentinel-2 MSI (Multispectral Instruments), and Hyperion satellites were collected from the USGS and the Scientific Hub ESA-Copernicus on-line databases, and integrated with Google Earth imagery. The visual interpretation of the images, mostly based on the brightness contrast (high and low reflectance values) and aimed to the recognition of traces, has been facilitated by the RGB combinations of the spectral bands most sensitive to lithology and moisture content and supported by a semi-automatic processing, including unsupervised classification and the spectral bands Principal Component Analysis (PCA). Multitemporal analysis of satellite imagery have been also performed. Two main traces, interpreted as meanders, have been analyzed for their sedimentological and stratigraphic characteristics. Following a field survey aimed to describe the morphology, grain-size, colors, and accessory materials of surface deposits, 11 soil samples have been collected for the extraction of the reflectance spectral signature and coring along the traces and in adjacent areas (bright and dark portions). Cores have been sampled for benthic foraminifer/ostracod analysis (42 samples) and stratigraphic cross-sections were constructed transversal to the meandering traces. Nine

  20. Multiple Imputation of Groundwater Data to Evaluate Spatial and Temporal Anthropogenic Influences on Subsurface Water Fluxes in Los Angeles, CA

    NASA Astrophysics Data System (ADS)

    Manago, K. F.; Hogue, T. S.; Hering, A. S.

    2014-12-01

    In the City of Los Angeles, groundwater accounts for 11% of the total water supply on average, and 30% during drought years. Due to ongoing drought in California, increased reliance on local water supply highlights the need for better understanding of regional groundwater dynamics and estimating sustainable groundwater supply. However, in an urban setting, such as Los Angeles, understanding or modeling groundwater levels is extremely complicated due to various anthropogenic influences such as groundwater pumping, artificial recharge, landscape irrigation, leaking infrastructure, seawater intrusion, and extensive impervious surfaces. This study analyzes anthropogenic effects on groundwater levels using groundwater monitoring well data from the County of Los Angeles Department of Public Works. The groundwater data is irregularly sampled with large gaps between samples, resulting in a sparsely populated dataset. A multiple imputation method is used to fill the missing data, allowing for multiple ensembles and improved error estimates. The filled data is interpolated to create spatial groundwater maps utilizing information from all wells. The groundwater data is evaluated at a monthly time step over the last several decades to analyze the effect of land cover and identify other influencing factors on groundwater levels spatially and temporally. Preliminary results show irrigated parks have the largest influence on groundwater fluctuations, resulting in large seasonal changes, exceeding changes in spreading grounds. It is assumed that these fluctuations are caused by watering practices required to sustain non-native vegetation. Conversely, high intensity urbanized areas resulted in muted groundwater fluctuations and behavior decoupling from climate patterns. Results provides improved understanding of anthropogenic effects on groundwater levels in addition to providing high quality datasets for validation of regional groundwater models.

  1. Modelling microbially induced carbonate precipitation and its influence on CO2 and water flow in the subsurface

    NASA Astrophysics Data System (ADS)

    Ebigbo, A.; Helmig, R.; Gerlach, R.; Cunningham, A. B.; Phillips, A.

    2011-12-01

    A numerical model is presented which is capable of simulating and investigating the development of a microbially mediated hydraulic barrier near the injection well of a CO2 storage site. The model accounts for the transport of bacteria in the porous medium, their accumulation as biofilms, and the role they play in the increased hydrolysis of urea -- leading to the precipitation of carbonate minerals. Additionally, the influence of the precipitates and biofilm on the flow of the two fluid phases (CO2 and water) through the porous medium is accounted for. Part of the model is validated with experiments involving saturated flow through sand-packed columns. This numerical model is a useful tool for the optimisation of strategies for the proposed technology involving the use of such microbially induced barriers to increase storage security near wellbores. It also aids in improving our understanding of the relevant processes.

  2. Biodegradation of subsurface oil in a tidally influenced sand beach: Impact of hydraulics and interaction with pore water chemistry

    NASA Astrophysics Data System (ADS)

    Geng, Xiaolong; Boufadel, Michel C.; Lee, Kenneth; Abrams, Stewart; Suidan, Makram

    2015-05-01

    The aerobic biodegradation of oil in tidally influenced beaches was investigated numerically in this work using realistic beach and tide conditions. A numerical model BIOMARUN, coupling a multiple-Monod kinetic model BIOB to a density-dependent variably saturated groundwater flow model 2-D MARUN, was used to simulate the biodegradation of low-solubility hydrocarbon and transport processes of associated solute species (i.e., oxygen and nitrogen) in a tidally influenced beach environment. It was found that different limiting factors affect different portions of the beach. In the upper intertidal zone, where the inland incoming nutrient concentration was large (1.2 mg N/L), oil biodegradation occurred deeper in the beach (i.e., 0.3 m below the surface). In the midintertidal zone, a reversal was noted where the biodegradation was fast at shallow locations (i.e., 0.1 m below the surface), and it was due to the decrease of oxygen with depth due to consumption, which made oxygen the limiting factor for biodegradation. Oxygen concentration in the midintertidal zone exhibited two peaks as a function of time. One peak was associated with the high tide, when dissolved oxygen laden seawater filled the beach and a second oxygen peak was observed during low tides, and it was due to pore oxygen replenishment from the atmosphere. The effect of the capillary fringe (CF) height was investigated, and it was found that there is an optimal CF for the maximum biodegradation of oil in the beach. Too large a CF (i.e., very fine material) would attenuate oxygen replenishment (either from seawater or the atmosphere), while too small a CF (i.e., very coarse material) would reduce the interaction between microorganisms and oil in the upper intertidal zone due to rapid reduction in the soil moisture at low tide. This article was corrected on 22 JUN 2015. See the end of the full text for details.

  3. The Ligand Trans Influence Governs Conformation in Cobalamin-Dependent Methionine Synthase†

    PubMed Central

    Fleischhacker, Angela S.; Matthews, Rowena G.

    2008-01-01

    Cobalamin-dependent methionine synthase (MetH) of Escherichia coli is a large, modular enzyme that uses a cobalamin prosthetic group as a donor or acceptor in three separate methyl transfer reactions. The prosthetic group alternates between methylcobalamin and cob(I)alamin during catalysis as homocysteine is converted to methionine using a methyl group derived from methyltetrahydrofolate. Occasional oxidation of cob(I)alamin to cob(II)alamin inactivates the enzyme. Reductive methylation with flavodoxin and adenosylmethionine returns the enzyme to an active methylcobalamin state. At different points during the reaction cycle, the coordination of the cobalt of the cobalamin changes. The imidazole side chain of His759 coordinates to cobalamin in a “His-on” state and dissociates to produce a “His-off” state. The His-off state has been associated with a conformation of MetH that is poised for reactivation of cobalamin by reductive methylation rather than catalysis. Our studies on cob(III)alamins bound to MetH, specifically aqua-, methyl-, and n-propylcobalamin, show a correlation between the accessibility of the reactivation conformation and the order of the established ligand trans influence. The trans influence also controls the affinity of MetH in the cob(III)alamin form for flavodoxin. Flavodoxin, which acts to shift the conformational equilibrium towards the reactivation conformation, binds less tightly to MetH when the cob(III)alamin has a strong trans ligand and therefore has less positive charge on cobalt. These results are compared to those for cob(II)alamin MetH, illustrating that access to the reactivation conformation is governed by the net charge on the cobalt as well as the trans influence in cob(III)alamins. PMID:17924667

  4. The influence of sulfur and iron on dissolved arsenic concentrations in the shallow subsurface under changing redox conditions

    PubMed Central

    O'Day, Peggy A.; Vlassopoulos, Dimitri; Root, Robert; Rivera, Nelson

    2004-01-01

    The chemical speciation of arsenic in sediments and porewaters of aquifers is the critical factor that determines whether dissolved arsenic accumulates to potentially toxic levels. Sequestration of arsenic in solid phases, which may occur by adsorption or precipitation processes, controls dissolved concentrations. We present synchrotron x-ray absorption spectra of arsenic in shallow aquifer sediments that indicate the local structure of realgar (AsS) as the primary arsenic-bearing phase in sulfate-reducing conditions at concentrations of 1–3 mmol·kg–1, which has not previously been verified in sediments at low temperature. Spectroscopic evidence shows that arsenic does not substitute for iron or sulfur in iron sulfide minerals at the molecular scale. A general geochemical model derived from our field and spectroscopic observations show that the ratio of reactive iron to sulfur in the system controls the distribution of solid phases capable of removing arsenic from solution when conditions change from oxidized to reduced, the rate of which is influenced by microbial processes. Because of the difference in solubility of iron versus arsenic sulfides, precipitation of iron sulfide may remove sulfide from solution but not arsenic if precipitation rates are fast. The lack of incorporation of arsenic into iron sulfides may result in the accumulation of dissolved As(III) if adsorption is weak or inhibited. Aquifers particularly at risk for such geochemical conditions are those in which oxidized and reduced waters mix, and where the amount of sulfate available for microbial reduction is limited. PMID:15356340

  5. Influence of Mg2+ on CaCO3 precipitation during subsurface reactive transport in a homogeneous silicon-etched pore network

    NASA Astrophysics Data System (ADS)

    Boyd, Victoria; Yoon, Hongkyu; Zhang, Changyong; Oostrom, Mart; Hess, Nancy; Fouke, Bruce; Valocchi, Albert J.; Werth, Charles J.

    2014-06-01

    m) aragonite crystals formed primarily near to and below the center mixing zone with increasing Mg2+ concentration. Pore-scale modeling results are consistent with experiments, and indicate that all three polymorphs are thermodynamically favorable, with calcite and aragonite being the most favorable and having similar saturation ratios (SR > 100). The influence of Mg2+ on mineral precipitation rates is consistent with previous studies showing that calcite precipitation rates decrease with increasing Mg2+ concentrations. The precipitation of aragonite below the center-mixing zone is not predicted by thermodynamic SRs, but is consistent with the literature and our modeling results showing aragonite precipitation is kinetically more favorable in regions with higher Mg2+/Ca2+ ratios. Hence, both thermodynamic and kinetic constraints affect precipitation rates, the distribution of mineral polymorphs, and the corresponding extent of porosity occlusion. A tracer study demonstrated that mineral precipitation along the center-mixing zone under all experimental conditions led to substantial pore blockage. Imaging results suggest that with increasing Mg2+ concentration, slower crystal growth rates will increase the time period before pore blockage occurs, and the transition to more spherical and larger aragonite crystals below the center mixing line will increase pore occlusion and decrease mixing. Hence, understanding how Mg2+ affects calcium carbonate precipitation is very important for predicting mixing and reactive transport in subsurface reservoirs.

  6. The Influence of Subsurface Processes on Martian Basalts: An Example of Hydrothermal and Acidic Basalt Alteration at the Skouriotissa Mine, Cyprus

    NASA Astrophysics Data System (ADS)

    Bost, N.; Westall, F.; Ramboz, C.; Meunier, A.; Georgiou-Morisseau, E.; Foucher, F.

    2012-05-01

    Basalts are the prevalent rock type on Mars and the products of aqueously altered basalts are of particular interest tracers or subsurface processes. We present an analogue site on Earth: the skouriotissa mine in Cyprus.

  7. Influence of intraparticle diffusion on the desorption of radiocesium from the subsurface sediments at Hanford site, USA

    NASA Astrophysics Data System (ADS)

    Liu, C.; Zachara, J.; Smith, S.; McKinley, J.

    2002-12-01

    The desorption of 137Cs was investigated on sediments from the United States Hanford site. Pristine sediments and ones that were contaminated by the accidental release of alkaline 137Cs-containing high level nuclear wastes (HLW) were studied. The desorption of 137Cs was measured in Na+, K+, Rb+, and NH4+ electrolytes of variable concentration and pH, and in presence of a strong Cs-specific sorbent (self-assembled monolayer on a mesoporous support, SAMMS). 137Cs desorption from the HLW-contaminated Hanford sediments exhibited two distinct phases: an initial instantaneous release followed by a slow kinetic process. The first phase was driven by the equilibrium ion exchange of Cs located on the mica edges and its release extent followed the respective selectivities of the sediment for exchanging cations. The kinetic process was controlled by the intraparticle diffusion. X-ray microprobe analyses of Cs-sorbed micas showed that the 137Cs distributed not only on mica edges, but also within internal channels parallel to the basal plane. The diffusion rate was influenced by surface armoring and edge-channel collapse in solutions containing K+, Rb+, or NH4+. Scanning electron microscopic analysis revealed HLW-induced precipitation of secondary alumino-silicates on the edges of micaceous minerals. The removal of these precipitates by acidified ammonium oxalate extraction significantly increased the desorption rate and extent. Controlled desorption experiments using Cs-spiked pristine sediment indicated that the 137Cs diffusion rate was fast in Na-electrolyte, but much slower in the presence of K or Rb, suggesting an effect of edge-channel collapse. Model simulation using an intraparticle diffusion coupled with a cation exchange suggested that about 40 percent of total sorbed 137Cs in the contaminated Hanford sediment was exchangeable, including equilibrium and diffusive desorbable pools. This ratio increased to 60-80 percent after the removal of secondary precipitates. The

  8. Influence of Environmental Governance on Deforestation in Municipalities of the Brazilian Amazon.

    PubMed

    Dias, Lilian Fernandes Oliveira; Dias, David Valentim; Magnusson, William Ernest

    2015-01-01

    It has been argued that measuring governance at scales smaller than global could be an important management tool. However, current studies are conducted on a global scale and use expensive methods. In the present study, we assess whether the reported governance of Amazonian municipalities is related to reductions in deforestation. Economic activity (EA) affected general governance (G) positively (G = 0.81 +1.19 * EA, F1, 98 = 77.36, p < 0.001). Environmental governance (EG) was not affected significantly (p = 0.43) by deforestation before 2000 (PD), but increased significantly (p < 0.001) with general governance (G) (EG = -0.29 + 0.04 PD+0.98*OG, F2,97 = 42.6, p <0.001). Deforestation was not significantly related to environmental governance (p = 0.82). The only indirect effect of significant magnitude was the effect of the density of forest reserves on recent deforestation through deforestation before 2000, which was strongly negative (-0.49). It is possible to assess reported actions to promote municipal governance through official data. However, it is not enough to assume that general governance or environmental governance at the municipal level, as reflected in the official statistics, benefits environmental conservation. In fact, even at the level of nation states, at which most quantification of governance has been undertaken, it seems that the relationship between governance and environmental preservation is only an assumption, because we are aware of no study that supports that hypothesis quantitatively.

  9. Influence of Environmental Governance on Deforestation in Municipalities of the Brazilian Amazon

    PubMed Central

    Dias, Lilian Fernandes Oliveira; Dias, David Valentim; Magnusson, William Ernest

    2015-01-01

    It has been argued that measuring governance at scales smaller than global could be an important management tool. However, current studies are conducted on a global scale and use expensive methods. In the present study, we assess whether the reported governance of Amazonian municipalities is related to reductions in deforestation. Economic activity (EA) affected general governance (G) positively (G = 0.81 +1.19 * EA, F1, 98 = 77.36, p < 0.001). Environmental governance (EG) was not affected significantly (p = 0.43) by deforestation before 2000 (PD), but increased significantly (p < 0.001) with general governance (G) (EG = -0.29 + 0.04 PD+0.98*OG, F2,97 = 42.6, p <0.001). Deforestation was not significantly related to environmental governance (p = 0.82). The only indirect effect of significant magnitude was the effect of the density of forest reserves on recent deforestation through deforestation before 2000, which was strongly negative (-0.49). It is possible to assess reported actions to promote municipal governance through official data. However, it is not enough to assume that general governance or environmental governance at the municipal level, as reflected in the official statistics, benefits environmental conservation. In fact, even at the level of nation states, at which most quantification of governance has been undertaken, it seems that the relationship between governance and environmental preservation is only an assumption, because we are aware of no study that supports that hypothesis quantitatively. PMID:26208282

  10. Home Influences on the Academic Performance of Agricultural Science Students in Ikwuano Local Government Area of Abia State, Nigeria

    ERIC Educational Resources Information Center

    Ndirika, Maryann C.; Njoku, U. J.

    2012-01-01

    This study was conducted to investigate the home influences on the academic performance of agricultural science secondary school students in Ikwuano Local Government Area of Abia State. The instrument used in data collection was a validated questionnaire structured on a two point rating scale. Simple random sampling technique was used to select…

  11. Home Influences on the Academic Performance of Agricultural Science Students in Ikwuano Local Government Area of Abia State, Nigeria

    ERIC Educational Resources Information Center

    Ndirika, Maryann C.; Njoku, U. J.

    2012-01-01

    This study was conducted to investigate the home influences on the academic performance of agricultural science secondary school students in Ikwuano Local Government Area of Abia State. The instrument used in data collection was a validated questionnaire structured on a two point rating scale. Simple random sampling technique was used to select…

  12. Influence of Psychosocial Factors on Aging among the Aged in Ihitte-Uboma Local Government Area of Imo State, Nigeria

    ERIC Educational Resources Information Center

    Ojukwu, M. O.

    2016-01-01

    The major aim of this study was to examine influence of psychosocial factors on aging among the aged in Ihitte Uboma Local Government Area of Imo State, Nigeria. Ex-post facto or casual comparative research design was adopted for the study. Two hundred and twenty-five (225) old people were selected through random sampling for the study.…

  13. Factors Influencing Low Level of Women Participation in Literacy Programme in Maiha Local Government Area of Adamawa State

    ERIC Educational Resources Information Center

    Daniel, Aminchi

    2015-01-01

    This study was designed to determine the extent to which poverty, gender stereotype, socio-cultural belief and lack of awareness influence low level of women participation in literacy programme in Maiha Local Government Area of Adamawa State. Survey designed was adopted for the study and a sample consisting of three hundred (300) women who were…

  14. Influence of crystallite microstrain on surface complexes governing the metastable equilibrium solubility behavior of carbonated apatites.

    PubMed

    Papangkorn, Kongnara; Yan, Guang; Heslop, Dustin D; Moribe, Kunikazu; Baig, Arif A; Otsuka, Makoto; Higuchi, William I

    2008-04-01

    This study was on the influence of the mineral phase crystallite microstrain (CM) on the nature of the surface complex (SC) governing the metastable equilibrium solubility (MES) behavior of carbonated apatites (CAPs) in aqueous acidic media (0.10 M acetate buffers, with and without fluoride, 0.50 M ionic strength maintained with NaCl). The MES behavior of a set of four CAPs (synthesized at 85 degrees C by a precipitation method) of increasing CM and therefore of increasing MES (CAP4 > CAP3 > CAP2 > CAP1) was quantified. The following were the findings. For CAP1 and CAP2, the SCs deduced were Ca10(PO4)6(OH)2 and Ca10(PO4)6F2 for the nonfluoride and the fluoride cases, respectively. For CAP3 and CAP4, the SCs deduced were Ca9.5(PO4)6OH or Ca9.5(HPO4)(PO4)5(OH)2 and NaCa9.5(PO4)6F2 for the nonfluoride and the fluoride cases, respectively. These results together with that from an earlier limited study show that the Ca/P ratio of the SC decreases from 1.67 to 1.58 to 1.50 with increasing CM of the CAPs; this relationship inversely correlates with the chemistry of maturation of aqueously precipitated defective apatites. Also the SCs do not appear to exist as a continuous series and only a few SCs may account for the MES behavior over a wide range of CAP preparations.

  15. Influence of Mg2+ on CaCO3 precipitation during subsurface reactive transport in a homogeneous silicon-etched pore network

    SciTech Connect

    Boyd, Victoria; Yoon, Hongkyu; Zhang, Changyong; Oostrom, Martinus; Hess, Nancy J.; Fouke, Bruce W.; Valocchi, Albert J.; Werth, Charles J.

    2014-04-04

    Calcium carbonate (CaCO3) geochemical reactions exert a fundamental control on the evolution of porosity and permeability in shallow-to-deep subsurface siliciclastic and limestone rock reservoirs. As a result, these carbonate water-rock interactions play a critically important role in research on groundwater remediation, geological carbon sequestration, and hydrocarbon exploration. A study was undertaken to determine the effects of Mg2+ concentration on CaCO3 crystal morphology, precipitation rate, and porosity occlusion under flow and mixing conditions similar to those in subsurface aquifers.

  16. Influence of Sub-Surface Irrigation on Soil Conditions and Water Irrigation Efficiency in a Cherry Orchard in a Hilly Semi-Arid Area of Northern China

    PubMed Central

    Peng, Gao; Bing, Wang; Guangcan, Zhang

    2013-01-01

    Sub-surface irrigation (SUI) is a new water-saving irrigation technology. To explore the influence of SUI on soil conditions in a cherry orchard and its water-saving efficiency, experiments were conducted from 2009 to 2010 using both SUI and flood irrigation (FLI) and different SUI quotas in hilly semi-arid area of northern China. The results demonstrated the following: 1) The bulk density of the soil under SUI was 6.8% lower than that of soil under FLI (P<0.01). The total soil porosity, capillary porosity and non-capillary porosity of soils using SUI were 11.7% (P<0.01), 8.7% (P<0.01) and 43.8% (P<0.01) higher than for soils using FLI. 2) The average soil temperatures at 0, 5, 10, 15 and 20 cm of soil depth using SUI were 1.7, 1.1, 0.7, 0.4 and 0.3°C higher than those for FLI, specifically, the differences between the surface soil layers were more significant. 3) Compared with FLI, the average water-saving efficiency of SUI was 55.6%, and SUI increased the irrigation productivity by 7.9-12.3 kg m-3 ha-1. 4) The soil moisture of different soil layers using SUI increased with increases in the irrigation quotas, and the soil moisture contents under SUI were significantly higher in the 0-20 cm layer and in the 21-50 cm layer than those under FLI (P<0.01). 5) The average yields of cherries under SUI with irrigation quotas of 80-320 m3 ha-1 were 8.7%-34.9% higher than those in soil with no irrigation (CK2). The average yields of cherries from soils using SUI were 4.5%-12.2% higher than using FLI. It is appropriate to irrigate 2-3 times with 230 m3 ha-1 per application using SUI in a year with normal rainfall. Our findings indicated that SUI could maintain the physical properties, greatly improve irrigation water use efficiency, and significantly increase fruit yields in hilly semi-arid areas of northern China. PMID:24039986

  17. Subsurface Imaging with the Scanning Microwave Microscope

    NASA Astrophysics Data System (ADS)

    Kopanski, Joseph; You, Lin; Michelson, Jonathan; Hitz, Emily; Obeng, Yaw; Back End of the Line Reliability; Metrology Project Team

    2015-03-01

    The scanning microwave microscope (SMM) forms images from the reflected amplitude and phase of an incident RF (~ 2.3 GHz) signal. The reflected signal is a function of the properties of the tip-sample contact, but can also be influenced by buried interfaces and subsurface variations of the sample permittivity. This mechanism allows limited imaging of conductors buried within dielectrics, voids within metal, or multiple metal layers with different permittivity. Subsurface SMM data acquisition modes include passive and various active data acquisition modes. The theory of sub-surface imaging with SMM and COMSOL multi-physics simulations of specific situations will be presented. Measurements of specifically designed test structures and correlation with simulations show the sensitivity and resolution of the technique applied to imaging subsurface metal lines embedded in dielectric. Applications include metrology for back end of the line (BEOL) multi-level metallization and three-dimensional integrated circuits (3D-ICs).

  18. The Stem Advisory Forum: A Means of Allowing People to Influence the Government's STEM Initiatives

    ERIC Educational Resources Information Center

    Onion, Alice; Follett, Brian

    2011-01-01

    This paper gives a short overview of the UK government's STEM agenda and then considers one aspect in depth--the STEM Advisory Forum. It explains how the Forum operates to draw together views from across the STEM community through online discussions and face-to-face events. Four examples are given of topics that have been dealt with by the Forum.…

  19. An Exploration of the Factors Influencing the Adoption of an IS Governance Framework

    ERIC Educational Resources Information Center

    Parker, Sharon L.

    2013-01-01

    This research explored IT governance framework adoption, leveraging established IS theories. It applied both the technology acceptance model (TAM) and the technology, organization, environment (TOE) models. The study consisted of developing a model utilizing TOE and TAM, deriving relevant hypotheses. Interviews with a group of practitioners…

  20. An Exploration of the Factors Influencing the Adoption of an IS Governance Framework

    ERIC Educational Resources Information Center

    Parker, Sharon L.

    2013-01-01

    This research explored IT governance framework adoption, leveraging established IS theories. It applied both the technology acceptance model (TAM) and the technology, organization, environment (TOE) models. The study consisted of developing a model utilizing TOE and TAM, deriving relevant hypotheses. Interviews with a group of practitioners…

  1. Electrical Subsurface Grounding Analysis

    SciTech Connect

    J.M. Calle

    2000-11-01

    The purpose and objective of this analysis is to determine the present grounding requirements of the Exploratory Studies Facility (ESF) subsurface electrical system and to verify that the actual grounding system and devices satisfy the requirements.

  2. Ceramic subsurface marker prototypes

    SciTech Connect

    Lukens, C.E.

    1985-05-02

    The client submitted 5 sets of porcelain and stoneware subsurface (radioactive site) marker prototypes (31 markers each set). The following were determined: compressive strength, thermal shock resistance, thermal crazing resistance, alkali resistance, color retention, and chemical resistance.

  3. Subsurface Microbiology and Biogeochemistry

    SciTech Connect

    Fredrickson, Jim K.; Fletcher, Madilyn

    2001-05-01

    Jim contributed a chapter to this book, in addition to co-editing it with Madilyn Fletcher. Fredrickson, J. K., and M. Fletcher. (eds.) 2001 Subsurface Microbiology and Biogeochemistry. Wiley-Liss, Inc., New York.

  4. What influences government adoption of vaccines in developing countries? A policy process analysis.

    PubMed

    Munira, Syarifah Liza; Fritzen, Scott A

    2007-10-01

    This paper proposes a framework for examining the process by which government consideration and adoption of new vaccines takes place, with specific reference to developing country settings. The cases of early Hepatitis B vaccine adoption in Taiwan and Thailand are used to explore the relevance of explanatory factors identified in the literature as well as the need to go beyond a variable-centric focus by highlighting the role of policy context and process in determining the pace and extent of adoption. The cases suggest the feasibility and importance of modeling 'causal diversity'-the complex set of necessary and sufficient conditions leading to particular decisional outcomes-in a broad range of country contexts. A better understanding of the lenses through which government decision-makers filter information, and of the arenas in which critical decisions are shaped and taken, may assist both analysts (in predicting institutionalization of new vaccines) and advocates (in crafting targeted strategies to accelerate their diffusion).

  5. Stakeholder Perceptions of Governance: Factors Influencing Presidential Perceptions of Board Effectiveness

    ERIC Educational Resources Information Center

    Proper, Eve; Willmer, Wesley K.; Hartley, Harold V., III; Caboni, Timothy C.

    2009-01-01

    This article examines the factors that influence presidents' perceptions of board effectiveness in relation to their boards' fundraising role. Data from a survey of small college presidents are used to see what factors influence each of four areas of satisfaction: deciding policy, making financial contributions, referring donor prospects and…

  6. Governance regime and location influence avoided deforestation success of protected areas in the Brazilian Amazon.

    PubMed

    Nolte, Christoph; Agrawal, Arun; Silvius, Kirsten M; Soares-Filho, Britaldo S

    2013-03-26

    Protected areas in tropical countries are managed under different governance regimes, the relative effectiveness of which in avoiding deforestation has been the subject of recent debates. Participants in these debates answer appeals for more strict protection with the argument that sustainable use areas and indigenous lands can balance deforestation pressures by leveraging local support to create and enforce protective regulations. Which protection strategy is more effective can also depend on (i) the level of deforestation pressures to which an area is exposed and (ii) the intensity of government enforcement. We examine this relationship empirically, using data from 292 protected areas in the Brazilian Amazon. We show that, for any given level of deforestation pressure, strictly protected areas consistently avoided more deforestation than sustainable use areas. Indigenous lands were particularly effective at avoiding deforestation in locations with high deforestation pressure. Findings were stable across two time periods featuring major shifts in the intensity of government enforcement. We also observed shifting trends in the location of protected areas, documenting that between 2000 and 2005 strictly protected areas were more likely to be established in high-pressure locations than in sustainable use areas and indigenous lands. Our findings confirm that all protection regimes helped reduce deforestation in the Brazilian Amazon.

  7. Governance regime and location influence avoided deforestation success of protected areas in the Brazilian Amazon

    PubMed Central

    Nolte, Christoph; Agrawal, Arun; Silvius, Kirsten M.; Soares-Filho, Britaldo S.

    2013-01-01

    Protected areas in tropical countries are managed under different governance regimes, the relative effectiveness of which in avoiding deforestation has been the subject of recent debates. Participants in these debates answer appeals for more strict protection with the argument that sustainable use areas and indigenous lands can balance deforestation pressures by leveraging local support to create and enforce protective regulations. Which protection strategy is more effective can also depend on (i) the level of deforestation pressures to which an area is exposed and (ii) the intensity of government enforcement. We examine this relationship empirically, using data from 292 protected areas in the Brazilian Amazon. We show that, for any given level of deforestation pressure, strictly protected areas consistently avoided more deforestation than sustainable use areas. Indigenous lands were particularly effective at avoiding deforestation in locations with high deforestation pressure. Findings were stable across two time periods featuring major shifts in the intensity of government enforcement. We also observed shifting trends in the location of protected areas, documenting that between 2000 and 2005 strictly protected areas were more likely to be established in high-pressure locations than in sustainable use areas and indigenous lands. Our findings confirm that all protection regimes helped reduce deforestation in the Brazilian Amazon. PMID:23479648

  8. Subsurface Contamination Control

    SciTech Connect

    Y. Yuan

    2001-12-12

    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 the 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

  9. Subsurface Contamination Control

    SciTech Connect

    Y. Yuan

    2001-11-16

    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 the 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

  10. Commentary on the federal government's role in influencing e-prescribing use and research.

    PubMed

    Odukoya, Olufunmilola K; Chui, Michelle A

    2012-01-01

    Electronic prescribing (e-prescribing) is one of the most studied areas of health information technology due to advocacy for its use by influential organizations such as the Institute of Medicine (IOM). In the United States, the federal government has played a significant role in encouraging use of e-prescribing technology and in stimulating associated research nationwide. The federal government has increased e-prescribing research initiatives through agencies such as the Agency for Healthcare Research and Quality (AHRQ) and the Health Resources and Services Administration (HRSA). Initial initiatives focused on the development of standards for e-prescribing systems and implementation. In recent times, e-prescribing research initiatives have become more focused on identifying unintended consequences of using this technology and identifying new possibilities of use that were previously not envisioned. Continuous studies of how healthcare professionals are interfacing with this new technology, how systems have been implemented, and the impact of this technology on healthcare processes and outcomes are crucial.

  11. Government Agencies

    DTIC Science & Technology

    1988-05-01

    large, complex , and difficult to manage. U.S. Government procurement is the largest business enterprise in the world affecting the security...listed in this study.) With the single exception of rocket and spacecraft acquisitions, ship acquisitions are the highest cost and most complex ...acquisitions U.S. Government agencies undertake. Many factors influence the level of complexity for a given ship acquisition program. Between the Navy and

  12. An innovative approach for locating and evaluating subsurface pathways for nitrogen loss.

    PubMed

    Walthall, C L; Gish, T J; Daughtry, C S; Dulaney, W P; Kung, K J; McCarty, G; Timlin, D; Angier, J T; Buss, P; Houser, P R

    2001-12-04

    Fundamental watershed-scale processes governing chemical flux to neighboring ecosystems are so poorly understood that effective strategies for mitigating chemical contamination cannot be formulated. Characterization of evapotranspiration, surface runoff, plant uptake, subsurface preferential flow, behavior of the chemicals in neighboring ecosystems, and an understanding of how crop management practices influence these processes are needed. Adequate characterization of subsurface flow has been especially difficult because conventional sampling methods are ineffective for measuring preferential flow of water and solutes. A sampling strategy based on ground-penetrating radar (GPR) mapping of subsurface structures coupled with near real-time soil moisture data, surface topography, remotely sensed imagery, and a geographic information system (GIS) appears to offer a means of accurately identifying subsurface preferential flow pathways. Four small adjacent watersheds draining into a riparian wetland and first-order stream at the USDA-ARS Beltsville Agricultural Research Center, Beltsville, MD are being studied with this protocol. The spatial location of some preferential flow pathways for chemicals exiting these agricultural watersheds to the neighboring ecosystems have been identified. Confirmation of the pathways is via examination of patterns in yield monitor data and remote sensing imagery.

  13. The Six Pillars of Influence: How Insurgent Organizations Manipulate Governments, Populations, and Their Operatives

    DTIC Science & Technology

    2009-03-01

    Work, which has numerous business clients including IBM, Coca Cola , and Harvard University. C. CIALDINI’S PRINCIPLES OF INFLUENCE 1. Reciprocation...strict code of proper conduct and total submission to authority; without these ingredients commitment could not be complete” (Berman, 1974). Another

  14. Influence of Target Population Misspecification on Employee Perceptions at a Government Facility

    ERIC Educational Resources Information Center

    Smith, Joe Lee

    2014-01-01

    Numerous researchers have conducted qualitative and quantitative studies examining employee perceptions related to changes in their work environment based upon management/top-down (deductive) communication of vision, mission, and envisioned organization goals (Hofstede, Neuijen, Daval, Ohayv, & Sanders 1990), but research on the influence of…

  15. Influence of Target Population Misspecification on Employee Perceptions at a Government Facility

    ERIC Educational Resources Information Center

    Smith, Joe Lee

    2014-01-01

    Numerous researchers have conducted qualitative and quantitative studies examining employee perceptions related to changes in their work environment based upon management/top-down (deductive) communication of vision, mission, and envisioned organization goals (Hofstede, Neuijen, Daval, Ohayv, & Sanders 1990), but research on the influence of…

  16. Best Practice -- Subsurface Investigations

    SciTech Connect

    Clark Scott

    2010-03-01

    These best practices for Subsurface Survey processes were developed at the Idaho National Laboratory (INL) and later shared and formalized by a sub-committee, under the Electrical Safety Committee of EFCOG. The developed best practice is best characterized as a Tier II (enhanced) survey process for subsurface investigations. A result of this process has been an increase in the safety and lowering of overall cost, when utility hits and their related costs are factored in. The process involves improving the methodology and thoroughness of the survey and reporting processes; or improvement in tool use rather than in the tools themselves. It is hoped that the process described here can be implemented at other sites seeking to improve their Subsurface Investigation results with little upheaval to their existing system.

  17. Subsurface drainage erodes forested granitic terrane

    Treesearch

    Philip Durgin

    1984-01-01

    Abstract - Solution and landsliding, the dominant erosion processes in undisturbed forested mountainous watersheds, are both influenced by subsurface drainage. Biological processes that generate organic acids accelerate loss of dissolved solids by promoting the dissolution of primary minerals in granitic rock. These organic acids can also disperse the secondary...

  18. 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.

  19. Terrestrial Subsurface Ecosystem

    SciTech Connect

    Wilkins, Michael J.; Fredrickson, Jim K.

    2015-10-15

    The Earth’s crust is a solid cool layer that overlays the mantle, with a varying thickness of between 30-50 km on continental plates, and 5-10 km on oceanic plates. Continental crust is composed of a variety of igneous, metamorphic, and sedimentary rocks that weather and re-form over geologic cycles lasting millions to billions of years. At the crust surface, these weathered minerals and organic material combine to produce a variety of soils types that provide suitable habitats and niches for abundant microbial diversity (see Chapter 4). Beneath this soil zone is the subsurface. Once thought to be relatively free of microorganisms, recent estimates have calculated that between 1016-1017 g C biomass (2-19% of Earth’s total biomass) may be present in this environment (Whitman et al., 1998;McMahon and Parnell, 2014). Microbial life in the subsurface exists across a wide range of habitats: in pores associated with relatively shallow unconsolidated aquifer sediments to fractures in bedrock formations that are more than a kilometer deep, where extreme lithostatic pressures and temperatures are encountered. While these different environments contain varying physical and chemical conditions, the absence of light is a constant. Despite this, diverse physiologies and metabolisms enable microorganisms to harness energy and carbon for growth in water-filled pore spaces and fractures. Carbon and other element cycles are driven by microbial activity, which has implications for both natural processes and human activities in the subsurface, e.g., bacteria play key roles in both hydrocarbon formation and degradation. Hydrocarbons are a major focus for human utilization of the subsurface, via oil and gas extraction and potential geologic CO2 sequestration. The subsurface is also utilized or being considered for sequestered storage of high-level radioactive waste from nuclear power generation and residual waste from past production of weapons grade nuclear materials. While our

  20. Reported Pain During Labour – A Qualitative Study of Influencing Factors among Parturient During Confinement in Private or Government Hospital

    PubMed Central

    Ravishankar, M.; Hemanthkumar, V.R.

    2016-01-01

    Introduction Labour pain is distressing and it produces undue side effects both to the mother and the baby. The incidence is high in developing countries like India where the awareness about labour analgesia is still lacking. Aim It is to find out the incidence of labour pain and the influence of various described factors on pain with a comparison between patients admitted in a government set up with a private set up in a south Indian semi-urban area. Materials and Methods Two hundred continuous uneventful normal deliveries each in a Government (group G) and a private hospital (group P) were enrolled for the study. The reported pain during labour was noted 6-7 hours after delivery by interacting with the patient. The factors like age of the mother, sex and weight of the baby, literacy, socioeconomic status, the use of oxytocics and analgesia were evaluated. Results The incidence of severe pain was more in group G (43.5%) than group P (12%). There was no analgesic intervention in 68.5% in group G while it was 13.5% (27/200) in group P. Even among these 27 patients who did not receive analgesics, only three parturients reported severe pain. Even administration of analgesics in a Government set up did not decrease pain to a significant extent. There were richer and more literate patients in group P. Booked cases were less in group G. Logistic regression analyses to find out factors which influenced pain in either group was used. Gravida, analgesic intervention and admission in a Govt. hospital influenced the pain experience of the parturient. There was minimal antenatal preparation in both the groups. There were no post partum complications. Conclusion Mothers suffered from labour pain to a significant extent and there is an urgent need for awareness about labour analgesia. Primigravida, admission in a Govt. set up and analgesic interventions were the factors which influenced pain than others. Patients admitted in Govt. hospitals suffered more pain with less analgesic

  1. Reported Pain During Labour - A Qualitative Study of Influencing Factors among Parturient During Confinement in Private or Government Hospital.

    PubMed

    Parthasarathy, S; Ravishankar, M; Hemanthkumar, V R

    2016-03-01

    Labour pain is distressing and it produces undue side effects both to the mother and the baby. The incidence is high in developing countries like India where the awareness about labour analgesia is still lacking. It is to find out the incidence of labour pain and the influence of various described factors on pain with a comparison between patients admitted in a government set up with a private set up in a south Indian semi-urban area. Two hundred continuous uneventful normal deliveries each in a Government (group G) and a private hospital (group P) were enrolled for the study. The reported pain during labour was noted 6-7 hours after delivery by interacting with the patient. The factors like age of the mother, sex and weight of the baby, literacy, socioeconomic status, the use of oxytocics and analgesia were evaluated. The incidence of severe pain was more in group G (43.5%) than group P (12%). There was no analgesic intervention in 68.5% in group G while it was 13.5% (27/200) in group P. Even among these 27 patients who did not receive analgesics, only three parturients reported severe pain. Even administration of analgesics in a Government set up did not decrease pain to a significant extent. There were richer and more literate patients in group P. Booked cases were less in group G. Logistic regression analyses to find out factors which influenced pain in either group was used. Gravida, analgesic intervention and admission in a Govt. hospital influenced the pain experience of the parturient. There was minimal antenatal preparation in both the groups. There were no post partum complications. Mothers suffered from labour pain to a significant extent and there is an urgent need for awareness about labour analgesia. Primigravida, admission in a Govt. set up and analgesic interventions were the factors which influenced pain than others. Patients admitted in Govt. hospitals suffered more pain with less analgesic intervention possibly due to illiteracy. The increased

  2. Delineation of temporal variability and governing factors influencing the spatial variability of shallow groundwater chemistry in a tropical sedimentary island

    NASA Astrophysics Data System (ADS)

    Lin, Chin Yik; Abdullah, Mohd Harun; Praveena, Sarva Mangala; Yahaya, Aminatul Hawa Bt; Musta, Baba

    2012-04-01

    SummaryAn attempt has been made to delineate the temporal variability and factors governing the shallow groundwater chemistry using analysis of variance (ANOVA) and multivariate analysis notably R-mode factor (FA) and hierarchical cluster analysis (HCA). Subsequently, geostatistical isoplethic maps were applied to convey better understanding on the distribution of selected groundwater parameters. The Manukan Island's shallow aquifer with sedimentary setting that constantly abstracted for freshwater supply has been selected for this study. One-way ANOVA suggested that neither changes of tide level nor rainfall volume appeared to exert significant influence on the groundwater chemistry of the small island. Rather, the groundwater chemistry was greatly governed by influence from seawater intrusion, which characterized by considerable amount of Ca, Na, and Cl. Such condition was well explained by a Piper diagram, where most plots were situated at the middle diamond shaped diagram, indicating mixing condition. FA likewise revealed that the shallow groundwater receives marked influence from carbonate dissolution and silicate weathering processes, especially boreholes located in the inland area. This can be clearly noted from the distinct groupings of relationships among different factors. HCA classified boreholes into three groups according to their locations in the coastal area, suggesting significant chemical variations between boreholes with distance from coast. Such distribution pattern was particularly evident in the isoplethic map. Overall, it appears that the shallow groundwater in the tropical island is not an appropriate source for drinking water in concern to its exceptionally high salinity and several elevated minor elements (Mn, Pb, and Se). For this, it is suggested that efforts in exploring other alternative sources should be performed outright.

  3. Spatially distributed influence of agro-environmental factors governing nitrate fate and transport in an irrigated stream-aquifer system

    NASA Astrophysics Data System (ADS)

    Bailey, R. T.; Ahmadi, M.; Gates, T. K.; Arabi, M.

    2015-12-01

    Elevated levels of nitrate (NO3) in groundwater systems pose a serious risk to human populations and natural ecosystems. As part of an effort to remediate NO3 contamination in irrigated stream-aquifer systems, this study elucidates agricultural and environmental parameters and processes that govern NO3 fate and transport at the regional (500 km2), local (50 km2), and field scales (< 1 km2). Specifically, the revised Morris sensitivity analysis method was applied to a finite-difference nitrogen cycling and reactive transport model of a regional-scale study site in the lower Arkansas River valley in southeastern Colorado. The method was used to rank the influence of anthropogenic activities and natural chemical processes on NO3 groundwater concentration, NO3 mass leaching, and NO3 mass loading to the Arkansas River from the aquifer. Sensitivity indices were computed for the entire study area in aggregate as well as each canal command area, crop type, and individual grid cells. Results suggest that fertilizer loading, crop uptake, and heterotrophic denitrification govern NO3 fate and transport for the majority of the study area, although their order of influence on NO3 groundwater concentration and mass leaching varies according to crop type and command area. Canal NO3 concentration and rates of autotrophic denitrification, nitrification, and humus decomposition also dominate or partially dominate in other locations. Each factor, with the exception of O2 reduction rate, is the dominating influence on NO3 groundwater concentration at one or more locations within the study area. Results can be used to determine critical processes and key management actions for future data collection and remediation strategies, with efforts able to be focused on localized areas.

  4. An Evaluation of Subsurface Plumbing of a Hydrothermal Seep Field and Possible Influence from Local Seismicity from New Time-Series Data Collected at the Davis-Schrimpf Seep Field, Salton Trough, California

    NASA Astrophysics Data System (ADS)

    Rao, A.; Onderdonk, N.

    2016-12-01

    The Davis­-Schrimpf Seep Field (DSSF) is a group of approximately 50 geothermal mud seeps (gryphons) in the Salton Trough of southeastern California. Its location puts it in line with the mapped San Andreas Fault, if extended further south, as well as within the poorly-understood Brawley Seismic Zone. Much of the geomorphology, geochemistry, and other characteristics of the DSSF have been analyzed, but its subsurface structure remains unknown. Here we present data and interpretations from five new temperature time­series from four separate gryphons at the DSSF, and compare them both amongst themselves, and within the context of all previously collected data to identify possible patterns constraining the subsurface dynamics. Simultaneously collected time-series from different seeps were cross-correlated to quantify similarity. All years' time-series were checked against the record of local seismicity to identify any seismic influence on temperature excursions. Time-series captured from the same feature in different years were statistically summarized and the results plotted to examine their evolution over time. We found that adjacent vents often alternate in temperature, suggesting a switching of flow path of the erupted mud at the scale of a few meters or less. Noticeable warming over time was observed in most of the features with time-series covering multiple years. No synchronicity was observed between DSSF features' temperature excursions, and seismic events within a 24 kilometer radius covering most of the width of the surrounding Salton Trough.

  5. Subsurface connection methods for subsurface heaters

    DOEpatents

    Vinegar, Harold J.; Bass, Ronald Marshall; Kim, Dong Sub; Mason, Stanley Leroy; Stegemeier, George Leo; Keltner, Thomas Joseph; Carl, Jr., Frederick Gordon

    2010-12-28

    A system for heating a subsurface formation is described. The system includes a first elongated heater in a first opening in the formation. The first elongated heater includes an exposed metal section in a portion of the first opening. The portion is below a layer of the formation to be heated. The exposed metal section is exposed to the formation. A second elongated heater is in a second opening in the formation. The second opening connects to the first opening at or near the portion of the first opening below the layer to be heated. At least a portion of an exposed metal section of the second elongated heater is electrically coupled to at least a portion of the exposed metal section of the first elongated heater in the portion of the first opening below the layer to be heated.

  6. SUBSURFACE EMPLACEMENT TRANSPORTATION SYSTEM

    SciTech Connect

    T. Wilson; R. Novotny

    1999-11-22

    The objective of this analysis is to identify issues and criteria that apply to the design of the Subsurface Emplacement Transportation System (SET). The SET consists of the track used by the waste package handling equipment, the conductors and related equipment used to supply electrical power to that equipment, and the instrumentation and controls used to monitor and operate those track and power supply systems. Major considerations of this analysis include: (1) Operational life of the SET; (2) Geometric constraints on the track layout; (3) Operating loads on the track; (4) Environmentally induced loads on the track; (5) Power supply (electrification) requirements; and (6) Instrumentation and control requirements. This analysis will provide the basis for development of the system description document (SDD) for the SET. This analysis also defines the interfaces that need to be considered in the design of the SET. These interfaces include, but are not limited to, the following: (1) Waste handling building; (2) Monitored Geologic Repository (MGR) surface site layout; (3) Waste Emplacement System (WES); (4) Waste Retrieval System (WRS); (5) Ground Control System (GCS); (6) Ex-Container System (XCS); (7) Subsurface Electrical Distribution System (SED); (8) MGR Operations Monitoring and Control System (OMC); (9) Subsurface Facility System (SFS); (10) Subsurface Fire Protection System (SFR); (11) Performance Confirmation Emplacement Drift Monitoring System (PCM); and (12) Backfill Emplacement System (BES).

  7. Outrage Factors in Government Press Releases of Food Risk and Their Influence on News Media Coverage.

    PubMed

    Ju, Youngkee; Lim, Jeongsub; Shim, Minsun; You, Myoungsoon

    2015-08-01

    An appropriate level of risk perception should be a critical issue in modern "risk society." There have been many studies on the influences on risk perception. This study investigates whether risk communication scholar Dr. Peter Sandman's outrage factors intensify journalistic attention to health risks from food consumption. A content analysis of a health institution's press releases was conducted to examine 15 outrage factors of food risks conveyed in the governmental risk communication. In addition, the news stories covering the food risks informed by the press releases were calculated to evaluate the relation between outrage factors of a risk and the number of news stories covering the risk. Results showed that controllability was the most salient outrage factor, followed by trust, voluntariness, familiarity, and human origin; the greater the outrage score of a risk, the more news stories of the risk. For individual outrage factors, a risk with an implication of catastrophic potential was associated with an increase of news stories. Food providers' distrustful behaviors also influenced journalistic attention to the food risks. The implication of the findings to health message designers is discussed.

  8. Influence of surface wettability on transport mechanisms governing water droplet evaporation.

    PubMed

    Pan, Zhenhai; Weibel, Justin A; Garimella, Suresh V

    2014-08-19

    Prediction and manipulation of the evaporation of small droplets is a fundamental problem with importance in a variety of microfluidic, microfabrication, and biomedical applications. A vapor-diffusion-based model has been widely employed to predict the interfacial evaporation rate; however, its scope of applicability is limited due to incorporation of a number of simplifying assumptions of the physical behavior. Two key transport mechanisms besides vapor diffusion-evaporative cooling and natural convection in the surrounding gas-are investigated here as a function of the substrate wettability using an augmented droplet evaporation model. Three regimes are distinguished by the instantaneous contact angle (CA). In Regime I (CA ≲ 60°), the flat droplet shape results in a small thermal resistance between the liquid-vapor interface and substrate, which mitigates the effect of evaporative cooling; upward gas-phase natural convection enhances evaporation. In Regime II (60 ≲ CA ≲ 90°), evaporative cooling at the interface suppresses evaporation with increasing contact angle and counterbalances the gas-phase convection enhancement. Because effects of the evaporative cooling and gas-phase convection mechanisms largely neutralize each other, the vapor-diffusion-based model can predict the overall evaporation rates in this regime. In Regime III (CA ≳ 90°), evaporative cooling suppresses the evaporation rate significantly and reverses entirely the direction of natural convection induced by vapor concentration gradients in the gas phase. Delineation of these counteracting mechanisms reconciles previous debate (founded on single-surface experiments or models that consider only a subset of the governing transport mechanisms) regarding the applicability of the classic vapor-diffusion model. The vapor diffusion-based model cannot predict the local evaporation flux along the interface for high contact angle (CA ≥ 90°) when evaporative cooling is strong and the

  9. Tropical Indian Ocean subsurface temperature variability and the forcing mechanisms

    NASA Astrophysics Data System (ADS)

    Sayantani, Ojha; Gnanaseelan, C.

    2015-05-01

    The first two leading modes of interannual variability of sea surface temperature in the Tropical Indian Ocean (TIO) are governed by El Niño Southern Oscillation and Indian Ocean Dipole (IOD) respectively. TIO subsurface however does not co-vary with the surface. The patterns of the first mode of TIO subsurface temperature variability and their vertical structure are found to closely resemble the patterns of IOD and El Niño co-occurrence years. These co-occurrence years are characterized by a north-south subsurface dipole rather than a conventional IOD forced east-west dipole. This subsurface dipole is forced by wind stress curl anomalies, driven mainly by meridional shear in the zonal wind anomalies. A new subsurface dipole index (SDI) has been defined in this study to quantify the intensity of the north-south dipole mode. The SDI peaks during December to February (DJF), a season after the dipole mode index peaks. It is found that this subsurface north-south dipole is a manifestation of the internal mode of variability of the Indian Ocean forced by IOD but modulated by Pacific forcing. The seasonal evolution of thermocline, subsurface temperature and the corresponding leading modes of variability further support this hypothesis. Positive wind stress curl anomalies in the south and negative wind stress curl anomalies in the north of 5°S force (or intensify) downwelling and upwelling waves respectively during DJF. These waves induce strong subsurface warming in the south and cooling in the north (especially during DJF) and assist the formation and/or maintenance of the north-south subsurface dipole. A thick barrier layer forms in the southern TIO, supporting the long persistence of anomalous subsurface warming. To the best of our knowledge the existence of such north-south subsurface dipole in TIO is being reported for the first time.

  10. Mars penetrator: Subsurface science mission

    NASA Technical Reports Server (NTRS)

    Lumpkin, C. K.

    1974-01-01

    A penetrator system to emplace subsurface science on the planet Mars is described. The need for subsurface science is discussed, and the technologies for achieving successful atmospheric entry, Mars penetration, and data retrieval are presented.

  11. Tobacco industry attempts to influence and use the German government to undermine the WHO Framework Convention on Tobacco Control.

    PubMed

    Grüning, Thilo; Weishaar, Heide; Collin, Jeff; Gilmore, Anna B

    2012-01-01

    Germany has been identified as one of a few high-income countries that opposed a strong Framework Convention on Tobacco Control (FCTC), the WHO's first global public health treaty. This paper examines whether the tobacco industry had influenced the German position on the FCTC. Analysis of previously confidential tobacco industry documents. The tobacco industry has identified Germany as a key target within its global strategy against the FCTC. Building on an already supportive base, the industry appears to have successfully lobbied the German government, influencing Germany's position and argumentation on key aspects of the FCTC. It then used Germany in its efforts to weaken the FCTC. The evidence suggests that the industry enjoyed success in undermining the Federal Health Ministry's position and using Germany to limit the European Union negotiating mandate. The tactics used by the tobacco industry included the creation of controversy between the financial, trade and other ministries on one side and the health ministry on the other side, the use of business associations and other front groups to lobby on the industry's behalf and securing industry access to the FCTC negotiations via the International Standardization Organization. The evidence suggests that Germany played a major role in the tobacco industry's efforts to undermine the FCTC. Germany's position consistently served to protect industry interests and was used to influence and constrain other countries. Germany thus contributed significantly to attempts to weaken an international treaty and, in doing so, failed in its responsibility to advance global health.

  12. Emergency contraception in Peru: shifting government and donor policies and influences.

    PubMed

    Chávez, Susana; Coe, Anna-Britt

    2007-05-01

    Inclusion of emergency contraception in national family planning programmes is consistent with international agreements that countries should strive to ensure access to a wide range of contraceptive methods and promote voluntary, informed choice. Yet in 2005, USAID/Peru requested that its NGO grantees in Peru take a "neutral" position on emergency contraception in activities or materials that involve its funds. For many decades, donor countries have viewed conservative religious forces in low-income countries as an obstacle to expanding family planning programmes. Today, however, far-right organisations in the United States are having an unprecedented influence on US public policy, including in countries such as Peru. This article analyses shifts in USAID/Peru's policy on emergency contraception in Peru since 1992. In Peru today, there is widespread official and public support for making emergency contraception available. Given USAID's long support for family planning internationally and in Peru, the current policy appears to be the result of attacks by US far-right organisations carried out in synergy with sympathetic US public officials and anti-choice Peruvian allies.

  13. The influence of coastal upwelling and a river plume on the subsurface chlorophyll maximum over the shelf of the northeastern South China Sea

    NASA Astrophysics Data System (ADS)

    Lu, Zhongming; Gan, Jianping; Dai, Minhan; Cheung, Anson Y. Y.

    2010-07-01

    Frequently observed subsurface chlorophyll maximum (SCM) contributes substantial biomass to the waters over the continental shelf of the northeastern South China Sea (NSCS) but it has not been sufficiently investigated. In this study, observations and a three-dimensional coupled physical-biological numerical model were utilized to investigate the characteristics of the SCM under strong controls of coastal upwelling circulation and the Pearl River plume in the NSCS. The model captures the observed characteristics of the SCM in the NSCS reasonably well. Both the depth and intensity of the SCM are spatially variable and regulated by the variable upwelling circulation and associated plume distribution over the complex shelf topography. In nearshore waters, the SCM shoals and weakens towards the coast as a result of the upwelling of high nutrient low chlorophyll deep water while surface productivity is enhanced. The intensity of the SCM weakens when the surface layer is covered by the river plume because of the substantial reduction of photosynthetic active radiation (PAR). Strengthening upwelling-favorable wind weakens the intensity of the SCM due to dilution by the enhanced mixing, but the SCM depth remains relatively stable in the offshore water as a result of no apparent shift of the nutricline. Changing incident PAR leads to an interactive response in chlorophyll concentration, nutricline, and the depth of the SCM.

  14. Subsurface Ice Probe

    NASA Technical Reports Server (NTRS)

    Hecht, Michael; Carsey, Frank

    2005-01-01

    The subsurface ice probe (SIPR) is a proposed apparatus that would bore into ice to depths as great as hundreds of meters by melting the ice and pumping the samples of meltwater to the surface. Originally intended for use in exploration of subsurface ice on Mars and other remote planets, the SIPR could also be used on Earth as an alternative to coring, drilling, and melting apparatuses heretofore used to sample Arctic and Antarctic ice sheets. The SIPR would include an assembly of instrumentation and electronic control equipment at the surface, connected via a tether to a compact assembly of boring, sampling, and sensor equipment in the borehole (see figure). Placing as much equipment as possible at the surface would help to attain primary objectives of minimizing power consumption, sampling with high depth resolution, and unobstructed imaging of the borehole wall. To the degree to which these requirements would be satisfied, the SIPR would offer advantages over the aforementioned ice-probing systems.

  15. Subsurface contaminants focus area

    SciTech Connect

    1996-08-01

    The US Department of Enregy (DOE) Subsurface Contaminants Focus Area is developing technologies to address environmental problems associated with hazardous and radioactive contaminants in soil and groundwater that exist throughout the DOE complex, including radionuclides, heavy metals; and dense non-aqueous phase liquids (DNAPLs). More than 5,700 known DOE groundwater plumes have contaminated over 600 billion gallons of water and 200 million cubic meters of soil. Migration of these plumes threatens local and regional water sources, and in some cases has already adversely impacted off-site rsources. In addition, the Subsurface Contaminants Focus Area is responsible for supplying technologies for the remediation of numerous landfills at DOE facilities. These landfills are estimated to contain over 3 million cubic meters of radioactive and hazardous buried Technology developed within this specialty area will provide efective methods to contain contaminant plumes and new or alternative technologies for development of in situ technologies to minimize waste disposal costs and potential worker exposure by treating plumes in place. While addressing contaminant plumes emanating from DOE landfills, the Subsurface Contaminants Focus Area is also working to develop new or alternative technologies for the in situ stabilization, and nonintrusive characterization of these disposal sites.

  16. Applications of subsurface microscopy.

    PubMed

    Tetard, Laurene; Passian, Ali; Farahi, Rubye H; Voy, Brynn H; Thundat, Thomas

    2012-01-01

    Exploring the interior of a cell is of tremendous importance in order to assess the effects of nanomaterials on biological systems. Outside of a controlled laboratory environment, nanomaterials will most likely not be conveniently labeled or tagged so that their translocation within a biological system cannot be easily identified and quantified. Ideally, the characterization of nanomaterials within a cell requires a nondestructive, label-free, and subsurface approach. Subsurface nanoscale imaging represents a real challenge for instrumentation. Indeed the tools available for high resolution characterization, including optical, electron or scanning probe microscopies, mainly provide topography images or require taggants that fluoresce. Although the intercellular environment holds a great deal of information, subsurface visualization remains a poorly explored area. Recently, it was discovered that by mechanically perturbing a sample, it was possible to observe its response in time with nanoscale resolution by probing the surface with a micro-resonator such as a microcantilever probe. Microcantilevers are used as the force-sensing probes in atomic force microscopy (AFM), where the nanometer-scale probe tip on the microcantilever interacts with the sample in a highly controlled manner to produce high-resolution raster-scanned information of the sample surface. Taking advantage of the existing capabilities of AFM, we present a novel technique, mode synthesizing atomic force microscopy (MSAFM), which has the ability to probe subsurface structures such as non-labeled nanoparticles embedded in a cell. In MSAFM mechanical actuators (PZTs) excite the probe and the sample at different frequencies as depicted in the first figure of this chapter. The nonlinear nature of the tip-sample interaction, at the point of contact of the probe and the surface of the sample, in the contact mode AFM configuration permits the mixing of the elastic waves. The new dynamic system comprises new

  17. The influence of surface low-salinity waters and cold subsurface water masses on picoplankton and ultraplankton distribution in the continental shelf off Rio de Janeiro, SE Brazil

    NASA Astrophysics Data System (ADS)

    Moser, G. A. O.; Castro, N. O.; Takanohashi, R. A.; Fernandes, A. M.; Pollery, R. C. G.; Tenenbaum, D. R.; Varela-Guerra, J.; Barrera-Alba, J. J.; Ciotti, A. M.

    2016-06-01

    The smallest phytoplankton groups named picoplankton and ultraplankton can be responsible for about 50-80% of the primary production rates in oligotrophic waters, due to their high surface/volume ratios that enables them for competitive growth rates relative to bigger cells under low light and low nutrient availability. The role of picoplankton and ultraplankton in coastal dynamic regions is less clear. This work relates the spatial distribution of autotrophic and heterotrophic components of these communities to the different properties of the water masses in the Southeastern Brazilian Continental Shelf, generally considered oligotrophic. Picoplankton and ultraplankton communities were related to nutrients present in the subsurface South Atlantic Central Water and waters with salinities below 35.5 originated from different estuarine systems. The enhance of autotrophs were also associated with a near shore feature related to topographic effects of São Sebastião Island to the local currents, first reported in this article. A core of higher chlorophyll a concentration, associated with the northeastward current flow at approximately 21 m depth below the surface, was identified as a dome-like shape. This core dissipated in the subsequent days suggesting that the flow towards NE was no longer a permanent feature two days after its observation. Locally enhancement of the contribution of picoplanktonic and ultraplanktonic autotrophs was observed in the surface and at the deep chlorophyll maximum depth associated with the chlorophyll core. Heterotrophs were more abundant inside and at the mouth of Guanabara Bay as well as inside Sepetiba Bay where light levels were low.

  18. FACTORS INFLUENCING THE CHOICE OF HEALTH CARE PROVIDING FACILITY AMONG WORKERS IN A LOCAL GOVERNMENT SECRETARIAT IN SOUTH WESTERN NIGERIA

    PubMed Central

    Uchendu, O.C.; Ilesanmi, O.S.; Olumide, A.E.

    2013-01-01

    Background: There is increasing interest in the choice of health care providing facility in Nigeria. Objectives: This study aimed to assess the factors influencing choice and satisfaction with health service providers among local government staff. Methods: A cross sectional survey of all 312 workers in a Local Government Secretariat in South West Nigeria was done. Chi Square and logistic regression analysis was done. Results: The mean age was 38.6 ± 7.5 years, 55% were females and 71.7% had tertiary education. The median monthly family income of the respondents was N 28, 000 (N3,000 – N500,000), with 24.4% earning a monthly income of N21, 000 to N30, 000. Many (72.3%) utilized public health facilities attributing the choice to the low cost of services. Respondents who are satisfied with their usual care providing facilities are 12.2 times more likely to have used public facilities than private facilities (95%, CI 3.431 – 43.114). Respondents who described the quality with ease of getting care/short waiting times as being good are 3.9 times more likely to have private facilities as their chosen health care providing facility (95%, CI 1.755 – 8.742). Cost/payment for service is 2.9 times more likely to predict the use of public health facility as the usual health care provider. Conclusion: Private facilities though costlier do not appear to be providing better services than public facilities. To increase access to health care the cost of services and the waiting time are important factors to address. PMID:25161426

  19. INEEL Subregional Conceptual Model Report Volume 2: Summary of Existing Knowledge of Geochemical Influences on the Fate and Transport of Contaminants in the Subsurface at the INEEL

    SciTech Connect

    Paul L. Wichlacz; Robert C. Starr; Brennon Orr

    2003-09-01

    . The documents that appeared to be the most pertinent were selected from further review. These documents are tabulated in the citation list. This report summarizes existing geochemical conceptual models, but does not attempt to generate a new conceptual model or select the ''right'' model. This document is organized as follows. Geochemical models are described in general in Section 2. Geochemical processes that control the transport and fate of contaminants introduced into groundwater are described in Section 3. The natural geochemistry of the Eastern Snake River Plain Aquifer (SRPA) is described in Section 4. The effect of waste disposal on the INEEL subsurface is described in Section 5. The geochemical behavior of the major contaminants is described in Section 6. Section 7 describes the site-specific geochemical models developed for various INEEL facilities.

  20. Geophysical subsurface imaging for ecological applications.

    PubMed

    Jayawickreme, Dushmantha H; Jobbágy, Esteban G; Jackson, Robert B

    2014-03-01

    Ecologists, ecohydrologists, and biogeochemists need detailed insights into belowground properties and processes, including changes in water, salts, and other elements that can influence ecosystem productivity and functioning. Relying on traditional sampling and observation techniques for such insights can be costly, time consuming, and infeasible, especially if the spatial scales involved are large. Geophysical imaging provides an alternative or complement to traditional methods to gather subsurface variables across time and space. In this paper, we review aspects of geophysical imaging, particularly electrical and electromagnetic imaging, that may benefit ecologists seeking clearer understanding of the shallow subsurface. Using electrical resistivity imaging, for example, we have been able to successfully show the effect of land-use conversions to agriculture on salt mobilization and leaching across kilometer-long transects and to depths of tens of meters. Recent advances in ground-penetrating radar and other geophysical imaging methods currently provide opportunities for subsurface imaging with sufficient detail to locate small (≥5 cm diameter) animal burrows and plant roots, observe soil-water and vegetation spatial correlations in small watersheds, estuaries, and marshes, and quantify changes in groundwater storage at local to regional scales using geophysical data from ground- and space-based platforms. Ecologists should benefit from adopting these minimally invasive, scalable imaging technologies to explore the subsurface and advance our collective research.

  1. Subsurface fracture spacing

    SciTech Connect

    Lorenz, J.C. ); Hill, R.E. )

    1991-01-01

    This study was undertaken in order to document and analyze the unique set of data on subsurface fracture characteristics, especially spacing, provided by the US Department of Energy's Slant Hole Completion Test well (SHCT-1) in the Piceance Basin, Colorado. Two hundred thirty-six (236) ft (71.9 m) of slant core and 115 ft (35.1 m) of horizontal core show irregular, but remarkably close, spacings for 72 natural fractures cored in sandstone reservoirs of the Mesaverde Group. Over 4200 ft (1280 m) of vertical core (containing 275 fractures) from the vertical Multiwell Experiment wells at the same location provide valuable information on fracture orientation, termination, and height, but only data from the SHCT-1 core allow calculations of relative fracture spacing. Within the 162-ft (49-m) thick zone of overlapping core from the vertical and deviated wellbores, only one fracture is present in vertical core whereas 52 fractures occur in the equivalent SHCT-1 core. The irregular distribution of regional-type fractures in these heterogeneous reservoirs suggests that measurements of average fracture spacing'' are of questionable value as direct input parameters into reservoir engineering models. Rather, deviated core provides data on the relative degree of fracturing, and confirms that cross fractures can be rare in the subsurface. 13 refs., 11 figs.

  2. Subsurface Biogeochemistry of Actinides

    SciTech Connect

    Kersting, Annie B.; Zavarin, Mavrik

    2016-06-29

    A major scientific challenge in environmental sciences is to identify the dominant processes controlling actinide transport in the environment. It is estimated that currently, over 2200 metric tons of plutonium (Pu) have been deposited in the subsurface worldwide, a number that increases yearly with additional spent nuclear fuel (Ewing et al., 2010). Plutonium has been shown to migrate on the scale of kilometers, giving way to a critical concern that the fundamental biogeochemical processes that control its behavior in the subsurface are not well understood (Kersting et al., 1999; Novikov et al., 2006; Santschi et al., 2002). Neptunium (Np) is less prevalent in the environment; however, it is predicted to be a significant long-term dose contributor in high-level nuclear waste. Our focus on Np chemistry in this Science Plan is intended to help formulate a better understanding of Pu redox transformations in the environment and clarify the differences between the two long-lived actinides. The research approach of our Science Plan combines (1) Fundamental Mechanistic Studies that identify and quantify biogeochemical processes that control actinide behavior in solution and on solids, (2) Field Integration Studies that investigate the transport characteristics of Pu and test our conceptual understanding of actinide transport, and (3) Actinide Research Capabilities that allow us to achieve the objectives of this Scientific Focus Area (SFA and provide new opportunities for advancing actinide environmental chemistry. These three Research Thrusts form the basis of our SFA Science Program (Figure 1).

  3. The Influence of Japanese Public Opinion and Government Policy on the Planning and Execution of U.S. - Japanese Bilateral Ground Exercises

    DTIC Science & Technology

    1990-06-01

    training exercises in other regions of the world, the Japanese government prohibits military training outside officially designated JGSDF training areas...different areas.) Additionally, Nikkyoso (the Japanese Teachers Union) instigated demonstrations along the periphery of the training area, which...conflict. Among the most significant consequences of this influence are inefficient, unrealistic training exercises, the lack of a unified command and

  4. Influence of Gas Composition and Exposure Cycle on the Formation of Surface and Subsurface Oxides in Iron-Aluminum-Based Alloys at High Temperatures

    NASA Astrophysics Data System (ADS)

    Bott, June H.; Yin, Hogbin; Sridhar, Seetharaman; Auinger, Michael

    2016-08-01

    The slab reheating process of binary iron-aluminum alloys and an industrial TRIP steel grade has been investigated in both dry and wet atmospheres. The presence of water vapor has a significant effect on the overall scale growth and internal corrosion depth. Heating rate greatly influences the porosity of the surface oxide layer with the surface getting more porous at faster heating rates. Nitride formation could be suppressed in the presence of water vapor, leading to a reduction of internal corrosion depth and a better formability of the final material. Experimental results were compared to thermodynamic predictions and critically discussed.

  5. Nonintrusive subsurface surveying capability

    SciTech Connect

    Tunnell, T.W.; Cave, S.P.

    1994-06-01

    This presentation describes the capabilities of a ground-pentrating radar (GPR) system developed by EG&G Energy Measurements (EM), a prime contractor to the Department of Energy (DOE). The focus of the presentation will be on the subsurface survey of DOE site TA-21 in Los Alamos, New Mexico. EG&G EM developed the system for the Department of Defense. The system is owned by the Department of the Army and currently resides at KO in Albuquerque. EM is pursuing efforts to transfer this technology to environmental applications such as waste-site characterization with DOE encouragement. The Army has already granted permission to use the system for the waste-site characterization activities.

  6. Containment of subsurface contaminants

    DOEpatents

    Corey, J.C.

    1994-09-06

    A barrier is disclosed for reducing the spread of a plume of subsurface contaminants. The apparatus includes a well system for injecting a fluid, such as air, just outside and below the periphery of the plume. The fluid is injected at a pressure sufficient to lower the hydraulic conductivity of the soil from the point of injection to the surface thus establishing a curtain-like barrier to groundwater movement. The barrier is established upgradient of the plume to divert groundwater away, or preferably completely around the plume to reduce the flow of groundwater into or out of the plume. The barrier enables the remediation of the confined contamination and then, when the injection of the fluid is halted, the barrier quickly dissipates. 5 figs.

  7. Containment of subsurface contaminants

    DOEpatents

    Corey, John C.

    1994-01-01

    A barrier for reducing the spread of a plume of subsurface contaminants. The apparatus includes a well system for injecting a fluid, such as air, just outside and below the periphery of the plume. The fluid is injected at a pressure sufficient to lower the hydraulic conductivity of the soil from the point of injection to the surface thus establishing a curtain-like barrier to groundwater movement. The barrier is established upgradient of the plume to divert groundwater away, or preferably completely around the plume to reduce the flow of groundwater into or out of the plume. The barrier enables the remediation of the confined contamination and then, when the injection of the fluid is halted, the barrier quickly dissipates.

  8. Quantifying the influence of the tobacco industry on EU governance: automated content analysis of the EU Tobacco Products Directive

    PubMed Central

    Costa, Hélia; Gilmore, Anna B; Peeters, Silvy; McKee, Martin; Stuckler, David

    2014-01-01

    Objective The tobacco industry spends large sums lobbying the European Union (EU) institutions, yet whether such lobbying significantly affects tobacco policy is not well understood. We used novel quantitative text mining techniques to evaluate the impact of industry pressure on the contested EU Tobacco Products Directive revision. Design Policy positions of 18 stakeholders including the tobacco industry, health NGOs and tobacco retailers were evaluated using their text submissions to EU consultations and impact assessments. Using Wordscores to calculate word frequencies, we developed a scale ranging from 0–tobacco industry to 1–public health organisations, which was then used to track changes in the policy position of the European Commission's 2010 consultation document, its 2012 final proposal and the European Parliament and Council's approved legislation in March 2014. Results Several stakeholders’ positions were closer to the tobacco industry than that of health NGOs, including retailers (ω=0.35), trade unions (ω=0.34) and publishers (ω=0.33 and ω=0.40). Over time the European Commission's position shifted towards the tobacco industry from ω=0.52 (95% CI 0.50 to 0.54) to ω=0.40 (95% CI 0.39 to 0.42). This transition reflected an increasing use of words pertaining to business and the economy in the Commission's document. Our findings were robust to alternative methods of scoring policy positions in EU documents. Conclusions Using quantitative text mining techniques, we observed that tobacco industry lobbying activity at the EU was associated with significant policy shifts in the EU Tobacco Products Directive legislation towards the tobacco industry's submissions. In the light of the Framework Convention on Tobacco Control, additional governance strategies are needed to prevent undue influence of the tobacco industry on EU policy making. PMID:25124165

  9. Quantifying the influence of the tobacco industry on EU governance: automated content analysis of the EU Tobacco Products Directive.

    PubMed

    Costa, Hélia; Gilmore, Anna B; Peeters, Silvy; McKee, Martin; Stuckler, David

    2014-11-01

    The tobacco industry spends large sums lobbying the European Union (EU) institutions, yet whether such lobbying significantly affects tobacco policy is not well understood. We used novel quantitative text mining techniques to evaluate the impact of industry pressure on the contested EU Tobacco Products Directive revision. Policy positions of 18 stakeholders including the tobacco industry, health NGOs and tobacco retailers were evaluated using their text submissions to EU consultations and impact assessments. Using Wordscores to calculate word frequencies, we developed a scale ranging from 0-tobacco industry to 1-public health organisations, which was then used to track changes in the policy position of the European Commission's 2010 consultation document, its 2012 final proposal and the European Parliament and Council's approved legislation in March 2014. Several stakeholders' positions were closer to the tobacco industry than that of health NGOs, including retailers (ω=0.35), trade unions (ω=0.34) and publishers (ω=0.33 and ω=0.40). Over time the European Commission's position shifted towards the tobacco industry from ω=0.52 (95% CI 0.50 to 0.54) to ω=0.40 (95% CI 0.39 to 0.42). This transition reflected an increasing use of words pertaining to business and the economy in the Commission's document. Our findings were robust to alternative methods of scoring policy positions in EU documents. Using quantitative text mining techniques, we observed that tobacco industry lobbying activity at the EU was associated with significant policy shifts in the EU Tobacco Products Directive legislation towards the tobacco industry's submissions. In the light of the Framework Convention on Tobacco Control, additional governance strategies are needed to prevent undue influence of the tobacco industry on EU policy making. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  10. Subsurface Samples: Collection and Processing

    SciTech Connect

    Long, Philip E.; Griffin, W. Timothy; Phelps, Tommy J.

    2002-12-01

    Microbiological data, interpretation, and conclusions from subsurface samples ultimately depend on the quality and representative character of the samples. Subsurface samples for environmental microbiology ideally contain only the microbial community and geochemical properties that are representative of the subsurface environment from which the sample was taken. To that end, sample contamination by exogenous microorganisms or chemical constituents must be eliminated or minimized, and sample analyses need to begin before changes in the microbial community or geochemical characteristics occur. This article presents sampling methods and sample processing techniques for collecting representative samples from a range of subsurface environments. Factors that should be considered when developing a subsurface sampling program are discussed, including potential benefits, costs, and limitations enabling researchers to evaluate the techniques that are presented and match them to their project requirements. Methods and protocols to address coring, sampling, processing and quality assessment issues are presented.

  11. Disruptive Influences on Research in Academic Pathology Departments: Proposed Changes to the Common Rule Governing Informed Consent for Research Use of Biospecimens and to Rules Governing Return of Research Results.

    PubMed

    Sobel, Mark E; Dreyfus, Jennifer C

    2017-01-01

    Academic pathology departments will be dramatically affected by proposed United States federal government regulatory initiatives. Pathology research will be substantially altered if proposed changes to the Common Rule (Code of Federal Regulations: Protection of Human Subjects title 45 CFR 46) and regulations governing the return of individual research results are approved and finalized, even more so now that the Precision Medicine initiative has been launched. Together, these changes are disruptive influences on academic pathology research as we know it, straining limited resources and compromising advances in diagnostic and academic pathology. Academic research pathologists will be challenged over the coming years and must demonstrate leadership to ensure the continued availability of and the ethical use of research pathology specimens.

  12. Subsurface Ventilation System Description Document

    SciTech Connect

    Eric Loros

    2001-07-25

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  13. Subsurface Ventilation System Description Document

    SciTech Connect

    2000-10-12

    The Subsurface Ventilation System supports the construction and operation of the subsurface repository by providing air for personnel and equipment and temperature control for the underground areas. Although the system is located underground, some equipment and features may be housed or located above ground. The system ventilates the underground by providing ambient air from the surface throughout the subsurface development and emplacement areas. The system provides fresh air for a safe work environment and supports potential retrieval operations by ventilating and cooling emplacement drifts. The system maintains compliance within the limits established for approved air quality standards. The system maintains separate ventilation between the development and waste emplacement areas. The system shall remove a portion of the heat generated by the waste packages during preclosure to support thermal goals. The system provides temperature control by reducing drift temperature to support potential retrieval operations. The ventilation system has the capability to ventilate selected drifts during emplacement and retrieval operations. The Subsurface Facility System is the main interface with the Subsurface Ventilation System. The location of the ducting, seals, filters, fans, emplacement doors, regulators, and electronic controls are within the envelope created by the Ground Control System in the Subsurface Facility System. The Subsurface Ventilation System also interfaces with the Subsurface Electrical System for power, the Monitored Geologic Repository Operations Monitoring and Control System to ensure proper and safe operation, the Safeguards and Security System for access to the emplacement drifts, the Subsurface Fire Protection System for fire safety, the Emplacement Drift System for repository performance, and the Backfill Emplacement and Subsurface Excavation Systems to support ventilation needs.

  14. Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming

    NASA Astrophysics Data System (ADS)

    Huang, Ping; Lin, I.-I.; Chou, Chia; Huang, Rong-Hui

    2015-05-01

    Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas.

  15. Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming.

    PubMed

    Huang, Ping; Lin, I-I; Chou, Chia; Huang, Rong-Hui

    2015-05-18

    Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas.

  16. Change in ocean subsurface environment to suppress tropical cyclone intensification under global warming

    PubMed Central

    Huang, Ping; Lin, I. -I; Chou, Chia; Huang, Rong-Hui

    2015-01-01

    Tropical cyclones (TCs) are hazardous natural disasters. Because TC intensification is significantly controlled by atmosphere and ocean environments, changes in these environments may cause changes in TC intensity. Changes in surface and subsurface ocean conditions can both influence a TC's intensification. Regarding global warming, minimal exploration of the subsurface ocean has been undertaken. Here we investigate future subsurface ocean environment changes projected by 22 state-of-the-art climate models and suggest a suppressive effect of subsurface oceans on the intensification of future TCs. Under global warming, the subsurface vertical temperature profile can be sharpened in important TC regions, which may contribute to a stronger ocean coupling (cooling) effect during the intensification of future TCs. Regarding a TC, future subsurface ocean environments may be more suppressive than the existing subsurface ocean environments. This suppressive effect is not spatially uniform and may be weak in certain local areas. PMID:25982028

  17. Fault and fracture patterns in low porosity chalk and their potential influence on sub-surface fluid flow-A case study from Flamborough Head, UK

    NASA Astrophysics Data System (ADS)

    Sagi, D. A.; De Paola, N.; McCaffrey, K. J. W.; Holdsworth, R. E.

    2016-10-01

    To better understand fault zone architecture and fluid flow in mesoscale fault zones, we studied normal faults in chalks with displacements up to 20 m, at two representative localities in Flamborough Head (UK). At the first locality, chalk contains cm-thick, interlayered marl horizons, whereas at the second locality marl horizons were largely absent. Cm-scale displacement faults at both localities display ramp-flat geometries. Mesoscale fault patterns in the marl-free chalk, including a larger displacement fault (20 m) containing multiple fault strands, show widespread evidence of hydraulically-brecciated rocks, whereas clays smears along fault planes, and injected into open fractures, and a simpler fault zone architecture is observed where marl horizons are present. Hydraulic brecciation and veins observed in the marl-free chalk units suggest that mesoscale fault patterns acted as localized fault conduit allowing for widespread fluid flow. On the other hand, mesoscale fault patterns developed in highly fractured chalk, which contains interlayered marl horizons can act as localized barriers to fluid flow, due to the sealing effect of clays smears along fault planes and introduced into open fractures in the damage zone. To support our field observations, quantitative analyses carried out on the large faults suggest a simple fault zone in the chalk with marl units with fracture density/connectivity decreasing towards the protolith. Where marls are absent, density is high throughout the fault zone, while connectivity is high only in domains nearest the fault core. We suggest that fluid flow in fractured chalk is especially influenced by the presence of marls. When present, it can smear onto fault planes, forming localised barriers. Fluid flow along relatively large displacement faults is additionally controlled by the complexity of the fault zone, especially the size/geometry of weakly and intensely connected damage zone domains.

  18. Factors Influencing the Selection of the Systems Integration Organizational Model Type for Planning and Implementing Government High-Technology Programs

    NASA Technical Reports Server (NTRS)

    Thomas, Leann; Utley, Dawn

    2006-01-01

    While there has been extensive research in defining project organizational structures for traditional projects, little research exists to support high technology government project s organizational structure definition. High-Technology Government projects differ from traditional projects in that they are non-profit, span across Government-Industry organizations, typically require significant integration effort, and are strongly susceptible to a volatile external environment. Systems Integration implementation has been identified as a major contributor to both project success and failure. The literature research bridges program management organizational planning, systems integration, organizational theory, and independent project reports, in order to assess Systems Integration (SI) organizational structure selection for improving the high-technology government project s probability of success. This paper will describe the methodology used to 1) Identify and assess SI organizational structures and their success rate, and 2) Identify key factors to be used in the selection of these SI organizational structures during the acquisition strategy process.

  19. Subsurface Facility System Description Document

    SciTech Connect

    Eric Loros

    2001-07-31

    The Subsurface Facility System encompasses the location, arrangement, size, and spacing of the underground openings. This subsurface system includes accesses, alcoves, and drifts. This system provides access to the underground, provides for the emplacement of waste packages, provides openings to allow safe and secure work conditions, and interfaces with the natural barrier. This system includes what is now the Exploratory Studies Facility. The Subsurface Facility System physical location and general arrangement help support the long-term waste isolation objectives of the repository. The Subsurface Facility System locates the repository openings away from main traces of major faults, away from exposure to erosion, above the probable maximum flood elevation, and above the water table. The general arrangement, size, and spacing of the emplacement drifts support disposal of the entire inventory of waste packages based on the emplacement strategy. The Subsurface Facility System provides access ramps to safely facilitate development and emplacement operations. The Subsurface Facility System supports the development and emplacement operations by providing subsurface space for such systems as ventilation, utilities, safety, monitoring, and transportation.

  20. The subsurface record for the Anthropocene based on the global analysis of deep wells

    NASA Astrophysics Data System (ADS)

    Rose, K.

    2016-12-01

    While challenges persist in the characterization of Earth's subsurface, over two centuries of exploration resulting in more than six million deep wellbores, offer insights into these systems. Characteristics of the subsurface vary and can be analyzed on a variety of spatial scales using geospatial tools and methods. Characterization and prediction of subsurface properties, such as depth, thickness, porosity, permeability, pressure and temperature, are important for models and interpretations of the subsurface. Subsurface studies contribute to insights and understanding of natural system but also enable predictions and assessments of subsurface resources and support environmental and geohazard assessments. As the geo-data science landscape shifts, becoming more open, there are increasing opportunities to fill knowledge gaps, mine large, interrelated datasets, and develop innovative methods to improve our understanding of the subsurface and the impacts of its exploration. In this study, a global dataset of more than 6,000,000 deep subsurface wells has been assembled using ArcGIS and Access, which reflects to a first order, the cumulative representation of over two centuries of drilling. Wellbore data, in general represent the only portal for direct measurement and characterization of deep subsurface properties. As human engineering of the subsurface evolves from a focus on hydrocarbon resource development to include subsurface waste product disposal (e.g. CO2, industrial waste, etc) and production of other deep subsurface resources, such as heat and water resources, there is the increasing need to improve characterization techniques and understand local and global ramifications of anthropogenic interaction with the subsurface. Data and geospatial analyses are reviewed to constrain the extent to which human interactions, not just with Earth's surface systems, atmospheric and geologic, but subsurface systems will result in an enduring signature of human influences on

  1. Titan Subsurface Reservoirs Artist Concept

    NASA Image and Video Library

    2014-09-03

    Scientists modeled how methane rainfall runoff would interact with the porous, icy crust of Saturn moon Titan and found that a subsurface methane aquifer might have its composition changed over time due to the formation of materials called clathrates.

  2. Interphase mass transfer between fluids in subsurface formations: A review

    NASA Astrophysics Data System (ADS)

    Agaoglu, Berken; Copty, Nadim K.; Scheytt, Traugott; Hinkelmann, Reinhard

    2015-05-01

    This paper presents a review of the state-of-the-art on interphase mass transfer between immiscible fluids in porous media with focus on the factors that have significant influence on this process. In total close to 300 papers were reviewed focusing to a large extent on the literature relating to NAPL contamination of the subsurface. The large body of work available on this topic was organized according to the length scale of the conducted studies, namely the pore, meso and field scales. The interrelation of interphase mass transfer at these different scales is highlighted. To gain further insight into interphase mass transfer, published studies were discussed and evaluated in terms of the governing flow configurations defined in terms of the wettability and mobility of the different phases. Such organization of the existing literature enables the identification of the interfacial domains that would have significant impact on interphase mass transfer. Available modeling approaches at the various length scales are discussed with regard to current knowledge on the physics of this process. Future research directions are also suggested.

  3. Interfacial kinematics and governing mechanisms under the influence of high strain rate impact conditions: Numerical computations of experimental observations

    NASA Astrophysics Data System (ADS)

    Raoelison, R. N.; Sapanathan, T.; Padayodi, E.; Buiron, N.; Rachik, M.

    2016-11-01

    This paper investigates the complex interfacial kinematics and governing mechanisms during high speed impact conditions. A robust numerical modelling technique using Eulerian simulations are used to explain the material response of the interface subjected to a high strain rate collision during a magnetic pulse welding. The capability of this model is demonstrated using the predictions of interfacial kinematics and revealing the governing mechanical behaviours. Numerical predictions of wave formation resulted with the upward or downward jetting and complex interfacial mixing governed by wake and vortex instabilities corroborate the experimental observations. Moreover, the prediction of the material ejection during the simulation explains the experimentally observed deposited particles outside the welded region. Formations of internal cavities along the interface is also closely resemble the resulted confined heating at the vicinity of the interface appeared from those wake and vortex instabilities. These results are key features of this simulation that also explains the potential mechanisms in the defects formation at the interface. These results indicate that the Eulerian computation not only has the advantage of predicting the governing mechanisms, but also it offers a non-destructive approach to identify the interfacial defects in an impact welded joint.

  4. U. S. Government Factors Influencing an Expansion of Study Abroad in the Middle East/North Africa

    ERIC Educational Resources Information Center

    Lane-Toomey, Cara

    2014-01-01

    As the United States continued to grow as a world power throughout the later part of the twentieth century, government funding for international education grew more closely connected to its national security needs. Federal funds have contributed to the growth of Area Studies and studying Less Commonly Taught Languages (LCTLs). Within the last ten…

  5. Factors influencing current interests and motivations of local governments to supply carbon offset credits from urban forestry

    Treesearch

    N. Poudyal; J. Siry; M. Bowker

    2009-01-01

    This study conducted a nationwide survey of municipal governments in the United States to assess their motivations, willingness, and technical as well as managerial capacities of cities to store carbon and sell carbon offsets. The analysis reveals that cities are fairly interested in selling carbon offsets and their interest in carbon trading is driven by the degree of...

  6. The influence of government actions on innovative activities in the development of environmental technologies to control sulfur dioxide emissions from stationary sources

    NASA Astrophysics Data System (ADS)

    Taylor, Margaret R.

    2001-12-01

    A better understanding of the influence of government actions on innovation is needed to inform future policy endeavors in areas ranging from industrial competitiveness to environmentally sustainable growth. Environmental control technology is a rich area for the study of this influence, since government has stronger incentives to promote innovation in these technologies than does the private sector. This dissertation investigated the case of sulfur dioxide (SO2) control technologies for electric power plants. In studying innovation in these technologies, it was very important to understand the details of these technologies as well as their long organizational history. These technologies have been affected by government actions ranging from government-sponsored research and technology transfer mechanisms to national regulatory events. The dissertation integrated insights from several complementary and repeatable innovation evaluation methods; this approach supported a fuller understanding of innovation while it structured the research results for potential future comparative analysis. Innovative activities were investigated through: patent activity analysis; technical content analysis and researcher co-authorship network analysis in a conference held for over twenty years; learning curve analysis for eighty-eight U.S. power plants; and a dozen expert interviews from a variety of innovative actors. Innovative outcomes were investigated through: analysis of observed improvements in newly installed technologies over time; evaluation of historic cost studies on standardized systems; and expert interviews. Several policy-relevant findings resulted from this dissertation. (1) The existence of national government regulation stimulated inventive activity more than government research support alone. (2) The existence and the anticipation of government regulation appeared to spur inventive activity, while regulatory stringency appeared to drive inventive activity and the

  7. Government Publications.

    ERIC Educational Resources Information Center

    Whitlatch, Jo Bell

    1979-01-01

    Reviews recent federal publications on government information, particularly in the area of general informational services, public access to government information and privacy issues, coordination of government information systems, and congressional information needs. (Author)

  8. Subsurface Geotechnical Parameters Report

    SciTech Connect

    D. Rigby; M. Mrugala; G. Shideler; T. Davidsavor; J. Leem; D. Buesch; Y. Sun; D. Potyondy; M. Christianson

    2003-12-17

    The Yucca Mountain Project is entering a the license application (LA) stage in its mission to develop the nation's first underground nuclear waste repository. After a number of years of gathering data related to site characterization, including activities ranging from laboratory and site investigations, to numerical modeling of processes associated with conditions to be encountered in the future repository, the Project is realigning its activities towards the License Application preparation. At the current stage, the major efforts are directed at translating the results of scientific investigations into sets of data needed to support the design, and to fulfill the licensing requirements and the repository design activities. This document addresses the program need to address specific technical questions so that an assessment can be made about the suitability and adequacy of data to license and construct a repository at the Yucca Mountain Site. In July 2002, the U.S. Nuclear Regulatory Commission (NRC) published an Integrated Issue Resolution Status Report (NRC 2002). Included in this report were the Repository Design and Thermal-Mechanical Effects (RDTME) Key Technical Issues (KTI). Geotechnical agreements were formulated to resolve a number of KTI subissues, in particular, RDTME KTIs 3.04, 3.05, 3.07, and 3.19 relate to the physical, thermal and mechanical properties of the host rock (NRC 2002, pp. 2.1.1-28, 2.1.7-10 to 2.1.7-21, A-17, A-18, and A-20). The purpose of the Subsurface Geotechnical Parameters Report is to present an accounting of current geotechnical information that will help resolve KTI subissues and some other project needs. The report analyzes and summarizes available qualified geotechnical data. It evaluates the sufficiency and quality of existing data to support engineering design and performance assessment. In addition, the corroborative data obtained from tests performed by a number of research organizations is presented to reinforce

  9. Improving subsurface hydrology in Earth System Models

    NASA Astrophysics Data System (ADS)

    Volk, J. M.; Clark, M. P.; Swenson, S. C.; Lawrence, D. M.; Tyler, S. W.

    2015-12-01

    Hydrologic processes that govern storage and transport of soil water and groundwater can have strong dynamic relationships with biogeochemical and atmospheric processes. This understanding has lead to a push to improve subsurface hydrologic parametrization in Earth System Models. Here we present results related to improving the implementation of soil moisture distribution, groundwater recharge/discharge, and subsurface drainage in the Community Land Model (CLM) which is the land surface model in the Community Earth System Model. First we identified geo-climatically different locations around the world to develop test cases. For each case we compare the vertical soil moisture distribution from the different implementations of 1D Richards equation, considering the boundary conditions, the treatment of the groundwater sink term, the vertical discretization, and the time stepping schemes. Generally, large errors in the hydrologic mass balance within the soil column occur when there is a large vertical gradient in soil moisture or when there is a shallow water table within a soil column. We then test the sensitivity of the algorithmic parameters that control temporal discretization and error tolerance of the adaptive time-stepping scheme to help optimize its computational efficiency. In addition, we vary the spatial discretization of soil layers (i.e. quantity of layers and their thicknesses) to better understand the sensitivity of vertical discretization of soil columns on soil moisture variability in ESMs. We present multivariate and multi-scale evaluation for the different model options and suggest ways to move forward with future model improvements.

  10. Armored Enzyme Nanoparticles for Remediation of Subsurface

    SciTech Connect

    Grate, Jay W.

    2005-09-01

    The remediation of subsurface contaminants is a critical problem for the Department of Energy, other government agencies, and our nation. Severe contamination of soil and groundwater exists at several DOE sites due to various methods of intentional and unintentional release. Given the difficulties involved in conventional removal or separation processes, it is vital to develop methods to transform contaminants and contaminated earth/water to reduce risks to human health and the environment. Transformation of the contaminants themselves may involve conversion to other immobile species that do not migrate into well water or surface waters, as is proposed for metals and radionuclides; or degradation to harmless molecules, as is desired for organic contaminants. Transformation of contaminated earth (as opposed to the contaminants themselves) may entail reductions in volume or release of bound contaminants for remediation.

  11. Tangible Exploration of Subsurface Data

    NASA Astrophysics Data System (ADS)

    Petrasova, A.; Harmon, B.; Mitasova, H.; White, J.

    2014-12-01

    Since traditional subsurface visualizations using 2D maps, profiles or charts can be difficult to interpret and often do not convey information in an engaging form, scientists are interested in developing alternative visualization techniques which would help them communicate the subsurface volume data with students and general public. We would like to present new technique for interactive visualization of subsurface using Tangible geospatial modeling and visualization system (Tangeoms). It couples a physical, three-dimensional model with geospatial modeling and analysis through a cycle of scanning and projection. Previous applications of Tangeoms were exploring the impact of terrain modifications on surface-based geophysical processes, such as overland water flow, sediment transport, and also on viewsheds, cast shadows or solar energy potential. However, Tangeoms can serve as a tool for exploring subsurface as well. By creating a physical sand model of a study area, removing the sand from different parts of the model and projecting the computed cross-sections, we can look under the ground as if we were at an excavation site, and see the actual data represented as a 3D raster in that particular part of the model. Depending on data availability, we can also incorporate temporal dimension. Our method is an intuitive and natural way of exploring subsurface data and for users, it represents an alternative to more abstract 3D computer visualization tools, by offering direct, tangible interface.

  12. Subsurface defect of amorphous carbon film imaged by near field acoustic microscopy

    NASA Astrophysics Data System (ADS)

    Zeng, J. T.; Zhao, K. Y.; Zeng, H. R.; Song, H. Z.; Zheng, L. Y.; Li, G. R.; Yin, Q. R.

    2008-05-01

    Amorphous carbon films were examined by low frequency scanning-probe acoustic microscopy (LF-SPAM). Local elastic properties as well as topography were imaged in the acoustic mode. Two kinds of subsurface defects were revealed by the LF-SPAM method. The influence of the subsurface defects on the elastic properties was also discussed. The ability to image subsurface defects was dependent on the scan area and the scan speed. Our results showed that the low frequency scanning-probe acoustic microscopy is a useful method for imaging subsurface defects with high resolution.

  13. Mechanistic assessment of hillslope transpiration controls of diel subsurface flow: a steady-state irrigation approach

    Treesearch

    H.R. Barnard; C.B. Graham; W.J. van Verseveld; J.R. Brooks; B.J. Bond; J.J. McDonnell

    2010-01-01

    Mechanistic assessment of how transpiration influences subsurface flow is necessary to advance understanding of catchment hydrology. We conducted a 24-day, steady-state irrigation experiment to quantify the relationships among soil moisture, transpiration and hillslope subsurface flow. Our objectives were to: (1) examine the time lag between maximum transpiration and...

  14. Effect of Periodic Surface Air Temperature Variations on Subsurface Thermal Structure with Vertical Fluid flow

    NASA Astrophysics Data System (ADS)

    D, R. V.; Ravi, M.; Srivastava, K.

    2016-12-01

    The influence of climate change on near subsurface temperatures is an important research topic for global change impact assessment at the regional scale. The varying temperature of the air over the surface in long term will disturb subsurface thermal structure. Groundwater flow is another important process which perturbs the thermal distribution into the subsurface. To investigate the effect of periodic air temperature on nonisothermal subsurface, one dimensional transient heat conduction-advection equation is solved numerically using finite element method. Thermal response of subsurface for periodic variations in surface air temperature (SAT) with robin type boundary condition on the surface with vertical ground water flow are calculated and the amplitude attenuation of propagation of surface temperature information in the subsurface for different scenarios of advection and convective coefficient are discussed briefly. The results show the coupled response of trigonometric variation in air temperature with surface temperatures along with ground water velocity has significant implications for the effects of climate change.

  15. Subsurface microbial habitats on Mars

    NASA Technical Reports Server (NTRS)

    Boston, P. J.; Mckay, C. P.

    1991-01-01

    We developed scenarios for shallow and deep subsurface cryptic niches for microbial life on Mars. Such habitats could have considerably prolonged the persistence of life on Mars as surface conditions became increasingly inhospitable. The scenarios rely on geothermal hot spots existing below the near or deep subsurface of Mars. Recent advances in the comparatively new field of deep subsurface microbiology have revealed previously unsuspected rich aerobic and anaerobic microbal communities far below the surface of the Earth. Such habitats, protected from the grim surface conditions on Mars, could receive warmth from below and maintain water in its liquid state. In addition, geothermally or volcanically reduced gases percolating from below through a microbiologically active zone could provide the reducing power needed for a closed or semi-closed microbial ecosystem to thrive.

  16. Endoscopic subsurface imaging in tissues

    SciTech Connect

    Demos, S G; Staggs, M; Radousky, H B

    2001-02-12

    The objective of this work is to develop endoscopic subsurface optical imaging technology that will be able to image different tissue components located underneath the surface of the tissue at an imaging depth of up to 1 centimeter. This effort is based on the utilization of existing technology and components developed for medical endoscopes with the incorporation of the appropriate modifications to implement the spectral and polarization difference imaging technique. This subsurface imaging technique employs polarization and spectral light discrimination in combination with image processing to remove a large portion of the image information from the outer layers of the tissue which leads to enhancement of the contrast and image quality of subsurface tissue structures.

  17. Measuring isotropic subsurface light transport.

    PubMed

    Happel, Kathrin; Dörsam, Edgar; Urban, Philipp

    2014-04-21

    Subsurface light transport can affect the visual appearance of materials significantly. Measuring and modeling this phenomenon is crucial for accurately reproducing colors in printing or for rendering translucent objects on displays. In this paper, we propose an apparatus to measure subsurface light transport employing a reference material to cancel out adverse signals that may bias the results. In contrast to other approaches, the setup enables improved focusing on rough surfaces (e.g. uncoated paper). We derive a measurement equation that may be used to deduce the point spread function (PSF) of subsurface light transport. Main contributions are the usage of spectrally-narrowband exchangeable LEDs allowing spectrally-resolved measurements and an approach based on quadratic programming for reconstructing PSFs in the case of isotropic light transport.

  18. Towed Subsurface Optical Communications Buoy

    NASA Technical Reports Server (NTRS)

    Stirbl, Robert C.; Farr, William H.

    2013-01-01

    The innovation allows critical, high-bandwidth submarine communications at speed and depth. This reported innovation is a subsurface optical communications buoy, with active neutral buoyancy and streamlined flow surface veins for depth control. This novel subsurface positioning for the towed communications buoy enables substantial reduction in water-absorption and increased optical transmission by eliminating the intervening water absorption and dispersion, as well as by reducing or eliminating the beam spread and the pulse spreading that is associated with submarine-launched optical beams.

  19. Colloids in groundwater: Their mobilization, subsurface transport, and sorption affinity for toxic chemicals

    SciTech Connect

    Not Available

    1991-01-01

    During the initial project period, we have pursued several activities with the overall goal of characterizing the roles of colloid in groundwater. First, we have collected soil cores from a site where we have previously found large quantities of kaolinite colloids in the groundwater. We have intensely investigated these cores to test our hypothesis that the colloids have been mobilized as a result of iron oxide dissolution. Next, we have constructed a soil core system in our laboratory with which we are attempting to mimic the factors that we think are governing colloid transport in the subsurface. Finally, we have pursued the issue of how well organic chemicals bind to the kinds of colloids that we are seeing at field sites. Together, with our knowledge of colloid mobility, we anticipate that this sorption data will enable us to predict the influence of groundwater colloids on contaminant fates in the subsurface. Our progress in each of these activities is described in this report. 7 refs., 12 figs.

  20. Scenario simulation based assessment of subsurface energy storage

    NASA Astrophysics Data System (ADS)

    Beyer, C.; Bauer, S.; Dahmke, A.

    2014-12-01

    -processes, mutual effects and influences on protected entities. The scenario analyses allow the deduction of monitoring concepts as well as a first methodology for large scale spatial planning of the geological subsurface. This concept is illustrated for different storage options and their impacts in space and time.

  1. Estimating and mapping ecological processes influencing microbial community assembly

    PubMed Central

    Stegen, James C.; Lin, Xueju; Fredrickson, Jim K.; Konopka, Allan E.

    2015-01-01

    Ecological community assembly is governed by a combination of (i) selection resulting from among-taxa differences in performance; (ii) dispersal resulting from organismal movement; and (iii) ecological drift resulting from stochastic changes in population sizes. The relative importance and nature of these processes can vary across environments. Selection can be homogeneous or variable, and while dispersal is a rate, we conceptualize extreme dispersal rates as two categories; dispersal limitation results from limited exchange of organisms among communities, and homogenizing dispersal results from high levels of organism exchange. To estimate the influence and spatial variation of each process we extend a recently developed statistical framework, use a simulation model to evaluate the accuracy of the extended framework, and use the framework to examine subsurface microbial communities over two geologic formations. For each subsurface community we estimate the degree to which it is influenced by homogeneous selection, variable selection, dispersal limitation, and homogenizing dispersal. Our analyses revealed that the relative influences of these ecological processes vary substantially across communities even within a geologic formation. We further identify environmental and spatial features associated with each ecological process, which allowed mapping of spatial variation in ecological-process-influences. The resulting maps provide a new lens through which ecological systems can be understood; in the subsurface system investigated here they revealed that the influence of variable selection was associated with the rate at which redox conditions change with subsurface depth. PMID:25983725

  2. Estimating and mapping ecological processes influencing microbial community assembly

    DOE PAGES

    Stegen, James C.; Lin, Xueju; Fredrickson, Jim K.; ...

    2015-05-01

    Ecological community assembly is governed by a combination of (i) selection resulting from among-taxa differences in performance; (ii) dispersal resulting from organismal movement; and (iii) ecological drift resulting from stochastic changes in population sizes. The relative importance and nature of these processes can vary across environments. Selection can be homogeneous or variable, and while dispersal is a rate, we conceptualize extreme dispersal rates as two categories; dispersal limitation results from limited exchange of organisms among communities, and homogenizing dispersal results from high levels of organism exchange. To estimate the influence and spatial variation of each process we extend a recentlymore » developed statistical framework, use a simulation model to evaluate the accuracy of the extended framework, and use the framework to examine subsurface microbial communities over two geologic formations. For each subsurface community we estimate the degree to which it is influenced by homogeneous selection, variable selection, dispersal limitation, and homogenizing dispersal. Our analyses revealed that the relative influences of these ecological processes vary substantially across communities even within a geologic formation. We further identify environmental and spatial features associated with each ecological process, which allowed mapping of spatial variation in ecological-process-influences. The resulting maps provide a new lens through which ecological systems can be understood; in the subsurface system investigated here they revealed that the influence of variable selection was associated with the rate at which redox conditions change with subsurface depth.« less

  3. Estimating and mapping ecological processes influencing microbial community assembly

    SciTech Connect

    Stegen, James C.; Lin, Xueju; Fredrickson, Jim K.; Konopka, Allan E.

    2015-05-01

    Ecological community assembly is governed by a combination of (i) selection resulting from among-taxa differences in performance; (ii) dispersal resulting from organismal movement; and (iii) ecological drift resulting from stochastic changes in population sizes. The relative importance and nature of these processes can vary across environments. Selection can be homogeneous or variable, and while dispersal is a rate, we conceptualize extreme dispersal rates as two categories; dispersal limitation results from limited exchange of organisms among communities, and homogenizing dispersal results from high levels of organism exchange. To estimate the influence and spatial variation of each process we extend a recently developed statistical framework, use a simulation model to evaluate the accuracy of the extended framework, and use the framework to examine subsurface microbial communities over two geologic formations. For each subsurface community we estimate the degree to which it is influenced by homogeneous selection, variable selection, dispersal limitation, and homogenizing dispersal. Our analyses revealed that the relative influences of these ecological processes vary substantially across communities even within a geologic formation. We further identify environmental and spatial features associated with each ecological process, which allowed mapping of spatial variation in ecological-process-influences. The resulting maps provide a new lens through which ecological systems can be understood; in the subsurface system investigated here they revealed that the influence of variable selection was associated with the rate at which redox conditions change with subsurface depth.

  4. SUBSURFACE VISUAL ALARM SYSTEM ANALYSIS

    SciTech Connect

    D.W. Markman

    2001-08-06

    The ''Subsurface Fire Hazard Analysis'' (CRWMS M&O 1998, page 61), and the document, ''Title III Evaluation Report for the Surface and Subsurface Communication System'', (CRWMS M&O 1999a, pages 21 and 23), both indicate the installed communication system is adequate to support Exploratory Studies Facility (ESF) activities with the exception of the mine phone system for emergency notification purposes. They recommend the installation of a visual alarm system to supplement the page/party phone system The purpose of this analysis is to identify data communication highway design approaches, and provide justification for the selected or recommended alternatives for the data communication of the subsurface visual alarm system. This analysis is being prepared to document a basis for the design selection of the data communication method. This analysis will briefly describe existing data or voice communication or monitoring systems within the ESF, and look at how these may be revised or adapted to support the needed data highway of the subsurface visual alarm. system. The existing PLC communication system installed in subsurface is providing data communication for alcove No.5 ventilation fans, south portal ventilation fans, bulkhead doors and generator monitoring system. It is given that the data communication of the subsurface visual alarm system will be a digital based system. It is also given that it is most feasible to take advantage of existing systems and equipment and not consider an entirely new data communication system design and installation. The scope and primary objectives of this analysis are to: (1) Briefly review and describe existing available data communication highways or systems within the ESF. (2) Examine technical characteristics of an existing system to disqualify a design alternative is paramount in minimizing the number of and depth of a system review. (3) Apply general engineering design practices or criteria such as relative cost, and degree of

  5. Government Should Subsidize, Not Tax, Marriage: Social Policies Have Influenced the Rate of Growth in Single-Parent Families

    ERIC Educational Resources Information Center

    Peterson, Paul E.

    2015-01-01

    Based upon reflections from the Moynihan report of 1965, this author notes that the root causes of the growth in single-parent families have yet to be well identified, making it difficult to figure out where to go next. However, from 1965 onward, social policies have influenced the rate of growth in single-parent families. What is needed is a…

  6. Government Should Subsidize, Not Tax, Marriage: Social Policies Have Influenced the Rate of Growth in Single-Parent Families

    ERIC Educational Resources Information Center

    Peterson, Paul E.

    2015-01-01

    Based upon reflections from the Moynihan report of 1965, this author notes that the root causes of the growth in single-parent families have yet to be well identified, making it difficult to figure out where to go next. However, from 1965 onward, social policies have influenced the rate of growth in single-parent families. What is needed is a…

  7. Soil Carbon Dioxide Production and Surface Fluxes: Subsurface Physical Controls

    NASA Astrophysics Data System (ADS)

    Risk, D.; Kellman, L.; Beltrami, H.

    Soil respiration is a critical determinant of landscape carbon balance. Variations in soil temperature and moisture patterns are important physical processes controlling soil respiration which need to be better understood. Relationships between soil respi- ration and physical controls are typically addressed using only surface flux data but other methods also exist which permit more rigorous interpretation of soil respira- tion processes. Here we use a combination of subsurface CO_{2} concentrations, surface CO_{2} fluxes and detailed physical monitoring of the subsurface envi- ronment to examine physical controls on soil CO_{2} production at four climate observatories in Eastern Canada. Results indicate that subsurface CO_{2} produc- tion is more strongly correlated to the subsurface thermal environment than the surface CO_{2} flux. Soil moisture was also found to have an important influence on sub- surface CO_{2} production, particularly in relation to the soil moisture - soil profile diffusivity relationship. Non-diffusive profile CO_{2} transport appears to be im- portant at these sites, resulting in a de-coupling of summertime surface fluxes from subsurface processes and violating assumptions that surface CO_{2} emissions are the result solely of diffusion. These results have implications for the study of soil respiration across a broad range of terrestrial environments.

  8. Subsurface Electromagnetic Target Characterization and Identification

    DTIC Science & Technology

    1979-06-01

    B. Subsurface Electromagnetic Video Pulse Radar System 5 C. The Subsurface Targets 11 D. Raw Measured Waveforms 14 E. Processed Waveforms 15 III...259 r i. I .. . . .... .. . . . . .;. . . . .. .. o _ • v . . • • • -• -. . .. -"... .. . II II LIST OF FIGURES Figure Page 1 The subsurface pulse ...7 3 Typical raw waveform received by the pulse radar system ..... ................... .i..... 9 4 Physical characteristics of the subsurface

  9. Military Government

    DTIC Science & Technology

    1949-07-01

    CGSC MG MILITARY GOVERNMENT LIBHARY ARI\\’IY WAR COLLEGE CJ\\RLISLE BARRACKS, PAa This text is approved for resident and extension-course...and functions · of ’ military government . It conforms ·substantially to the subject matter , of Field Manual 27-5, Civil Affairs/ Military Government ...Teaching experience at the Command and General Staff College has ···--·demonstrated the need for a military government text which brings to- gether

  10. Effect of polishing induced subsurface damages on laser induced damage in fused silica optics

    NASA Astrophysics Data System (ADS)

    He, Xiang; Zhao, Heng; Huang, Ying; Cai, Chao; Hu, JiangChuan; Ma, Ping

    2016-10-01

    Conventional used ceria polishing would induce both of Ce contaminants and subsurface damages, which mainly restricts the laser induced damage resistance of fused silica optics. To control the near surface defects, nanometer sized colloidal silica are used to polish fused silica optics after the normal ceria polishing process. Then the contaminant elements and subsurface damages of the polished samples were analyzed by secondary ion mass spectrometry and Nomarski microscopy. It reveals that ceria polishing would introduce lots of subsurface damages whereas colloidal silica polishing induces much fewer subsurface damages especially no fracture induced severe subsurface damages. The laser damage tests reveal that subsequent colloidal silica polishing of the ceria pre-polished samples could gradually eliminate the ceria polishing induced subsurface damages and lower the laser induced damage density accordingly with the increased polishing time. But unlike the damage density, only the severe subsurface damages are totally eliminated could the damage threshold be substantially improved. These results incline to indicate that the subsurface damages have great influence on the laser induced damage density and the fracture related severe subsurface damages will greatly restrict the damage threshold in polished optics.

  11. Migration And Entrapment Of Mercury In The Subsurface

    NASA Astrophysics Data System (ADS)

    M, D.; Nambi, I. M.

    2009-12-01

    Elemental mercury is an immiscible liquid with high density and high surface tension. The movement of mercury in the saturated subsurface region is therefore considered a case of two phase flow involving mercury and water and is expected to be governed by gravity, viscous and capillary forces. Fundamental investigation into the migration and capillary entrapment of mercury in the subsurface was done by controlled laboratory capillary pressure saturation experiments using mercury and water as non wetting and wetting fluid respectively. Residual mercury saturation and van Genuchten’s capillary entrapment parameters were determined independently for different sizes of porous media. Based on the experimental data, theoretical investigations were done on the role of the three predominant forces and their influence on mercury migration and entrapment. The effects of fluid density and interfacial tension and the influence of Capillary and Bond number on mercury entrapment were analyzed with the help of similar capillary pressure - saturation experiments using Tetrachloroethylene (PCE)-water fluid pair. Mercury-water systems exhibited a low residual saturation of 0.02 and 0.07 as compared to 0.16 and 0.27 for PCE-water systems. Less residual mercury saturation, lack of apparent hysteresis in capillary pressure saturation curves and large variation in van Genuchten’s parameters 'α'(inverse of displacement pressure) and ‘n’ (pore size distribution index) for mercury-water systems compared to PCE-water systems were observed. These anomalies between the two systems elucidate that the capillary trapping is equally dependent on the fluid characteristics especially for high density immiscible fluids. Gravity force nevertheless a predominant controlling factor in the migration of highly dense mercury, is counteracted by not less trivial capillary force which was 1.22x104 times higher than gravity force. The capillary forces thus surmount the gravity forces and cause

  12. Robust Representation of Integrated Surface-subsurface Hydrology at Watershed Scales

    NASA Astrophysics Data System (ADS)

    Painter, S. L.; Tang, G.; Collier, N.; Jan, A.; Karra, S.

    2015-12-01

    A representation of integrated surface-subsurface hydrology is the central component to process-rich watershed models that are emerging as alternatives to traditional reduced complexity models. These physically based systems are important for assessing potential impacts of climate change and human activities on groundwater-dependent ecosystems and water supply and quality. Integrated surface-subsurface models typically couple three-dimensional solutions for variably saturated flow in the subsurface with the kinematic- or diffusion-wave equation for surface flows. The computational scheme for coupling the surface and subsurface systems is key to the robustness, computational performance, and ease-of-implementation of the integrated system. A new, robust approach for coupling the subsurface and surface systems is developed from the assumption that the vertical gradient in head is negligible at the surface. This tight-coupling assumption allows the surface flow system to be incorporated directly into the subsurface system; effects of surface flow and surface water accumulation are represented as modifications to the subsurface flow and accumulation terms but are not triggered until the subsurface pressure reaches a threshold value corresponding to the appearance of water on the surface. The new approach has been implemented in the highly parallel PFLOTRAN (www.pflotran.org) code. Several synthetic examples and three-dimensional examples from the Walker Branch Watershed in Oak Ridge TN demonstrate the utility and robustness of the new approach using unstructured computational meshes. Representation of solute transport in the new approach is also discussed. Notice: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid

  13. Method of installing subsurface barrier

    SciTech Connect

    Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

    2007-10-09

    Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

  14. Global Health Governance and the Commercial Sector: A Documentary Analysis of Tobacco Company Strategies to Influence the WHO Framework Convention on Tobacco Control

    PubMed Central

    Weishaar, Heide; Collin, Jeff; Smith, Katherine; Grüning, Thilo; Mandal, Sema; Gilmore, Anna

    2012-01-01

    Background In successfully negotiating the Framework Convention on Tobacco Control (FCTC), the World Health Organization (WHO) has led a significant innovation in global health governance, helping to transform international tobacco control. This article provides the first comprehensive review of the diverse campaign initiated by transnational tobacco corporations (TTCs) to try to undermine the proposed convention. Methods and Findings The article is primarily based on an analysis of internal tobacco industry documents made public through litigation, triangulated with data from official documentation relating to the FCTC process and websites of relevant organisations. It is also informed by a comprehensive review of previous studies concerning tobacco industry efforts to influence the FCTC. The findings demonstrate that the industry's strategic response to the proposed WHO convention was two-fold. First, arguments and frames were developed to challenge the FCTC, including: claiming there would be damaging economic consequences; depicting tobacco control as an agenda promoted by high-income countries; alleging the treaty conflicted with trade agreements, “good governance,” and national sovereignty; questioning WHO's mandate; claiming the FCTC would set a precedent for issues beyond tobacco; and presenting corporate social responsibility (CSR) as an alternative. Second, multiple tactics were employed to promote and increase the impact of these arguments, including: directly targeting FCTC delegations and relevant political actors, enlisting diverse allies (e.g., mass media outlets and scientists), and using stakeholder consultation to delay decisions and secure industry participation. Conclusions TTCs' efforts to undermine the FCTC were comprehensive, demonstrating the global application of tactics that TTCs have previously been found to have employed nationally and further included arguments against the FCTC as a key initiative in global health governance

  15. Global health governance and the commercial sector: a documentary analysis of tobacco company strategies to influence the WHO framework convention on tobacco control.

    PubMed

    Weishaar, Heide; Collin, Jeff; Smith, Katherine; Grüning, Thilo; Mandal, Sema; Gilmore, Anna

    2012-01-01

    In successfully negotiating the Framework Convention on Tobacco Control (FCTC), the World Health Organization (WHO) has led a significant innovation in global health governance, helping to transform international tobacco control. This article provides the first comprehensive review of the diverse campaign initiated by transnational tobacco corporations (TTCs) to try to undermine the proposed convention. The article is primarily based on an analysis of internal tobacco industry documents made public through litigation, triangulated with data from official documentation relating to the FCTC process and websites of relevant organisations. It is also informed by a comprehensive review of previous studies concerning tobacco industry efforts to influence the FCTC. The findings demonstrate that the industry's strategic response to the proposed WHO convention was two-fold. First, arguments and frames were developed to challenge the FCTC, including: claiming there would be damaging economic consequences; depicting tobacco control as an agenda promoted by high-income countries; alleging the treaty conflicted with trade agreements, "good governance," and national sovereignty; questioning WHO's mandate; claiming the FCTC would set a precedent for issues beyond tobacco; and presenting corporate social responsibility (CSR) as an alternative. Second, multiple tactics were employed to promote and increase the impact of these arguments, including: directly targeting FCTC delegations and relevant political actors, enlisting diverse allies (e.g., mass media outlets and scientists), and using stakeholder consultation to delay decisions and secure industry participation. TTCs' efforts to undermine the FCTC were comprehensive, demonstrating the global application of tactics that TTCs have previously been found to have employed nationally and further included arguments against the FCTC as a key initiative in global health governance. Awareness of these strategies can help guard against

  16. INL Subsurface Wireless Sensor Platform

    SciTech Connect

    Dennis C. Kunerth; John M. Svoboda; James T. Johnson

    2005-10-01

    The Idaho National Laboratory is developing a versatile micro-power sensor interface platform for periodic subsurface sensing of environmental variables important to waste disposal sites such as volumetric moisture, water potential, and temperature. The key characteristics of the platform architecture are that the platform is passive until externally energized --no internal power source is required -- and that it communicates with a "reader" via short-range telemetry - no wires penetrate the subsurface. Other significant attributes include the potential for a long service life and a compact size that makes it well suited for retrofitting existing landfill structures. Functionally, the sensor package is "read" by a short-range induction coil that activates and powers the sensor platform as well as detects the sensor output via a radio frequency signal generated by the onboard programmable interface controller microchip. As a result, the platform has a functional subsurface communication range of approximately 10 to 12 ft. and can only accept sensors that require low power to operate.

  17. A technical investigation on tools and concepts for sustainable management of the subsurface in The Netherlands.

    PubMed

    Griffioen, Jasper; van Wensem, Joke; Oomes, Justine L M; Barends, Frans; Breunese, Jaap; Bruining, Hans; Olsthoorn, Theo; Stams, Alfons J M; van der Stoel, Almer E C

    2014-07-01

    In response to increasing use of the subsurface, there is a need to modernise policies on sustainable use of the subsurface. This holds in particular for the densely populated Netherlands. We aimed to analyse current practice of subsurface management and the associated pressure points and to establish a conceptual overview of the technical issues related to sustainable management of the subsurface. Case studies on the exploitation of subsurface resources (including spatial use of the subsurface) were analysed, examining social relevance, environmental impact, pressure points and management solutions. The case studies ranged from constructing underground garages to geothermal exploitation. The following issues were identified for the technological/scientific aspects: site investigation, suitability, risk assessment, monitoring and measures in the event of failure. Additionally, the following general issues were identified for the administrative aspects: spatial planning, option assessment, precaution, transparency, responsibility and liability. These issues were explored on their technological implications within the framework of sustainable management of the subsurface. This resulted into the following key aspects: (1) sustainability assessment, (2) dealing with uncertainty and (3) policy instruments and governance. For all three aspects, different options were identified which might have a legal, economic or ethical background. The technological implications of these backgrounds have been identified. A set of recommendations for sustainable management of the subsurface resources (incl. space) was established: (1) management should be driven by scarcity, (2) always implement closed loop monitoring when the subsurface activities are high-risk, (3) when dealing with unknown features and heterogeneity, apply the precautionary principle, (4) responsibility and liability for damage must be set out in legislation and (5) sustainability should be incorporated in all

  18. Subsurface Flow and Contaminant Transport Documentation and User's Guide

    SciTech Connect

    Aleman, S.E.

    1999-07-28

    This report documents a finite element code designed to model subsurface flow and contaminant transport, named FACT. FACT is a transient three-dimensional, finite element code designed to simulate isothermal groundwater flow, moisture movement, and solute transport in variably saturated and fully saturated subsurface porous media. The code is designed specifically to handle complex multi-layer and/or heterogeneous aquifer systems in an efficient manner and accommodates a wide range of boundary conditions. Additionally, 1-D and 2-D (in Cartesian coordinates) problems are handled in FACT by simply limiting the number of elements in a particular direction(s) to one. The governing equations in FACT are formulated only in Cartesian coordinates.

  19. Shallow subsurface storm flow in a forested headwater catchment: Observations and modeling using a modified TOPMODEL

    USGS Publications Warehouse

    Scanlon, T.M.; Raffensperger, J.P.; Hornberger, G.M.; Clapp, R.B.

    2000-01-01

    Transient, perched water tables in the shallow subsurface are observed at the South Fork Brokenback Run catchment in Shenandoah National Park, Virginia. Crest piezometers installed along a hillslope transect show that the development of saturated conditions in the upper 1.5 m of the subsurface is controlled by total precipitation and antecedent conditions, not precipitation intensity, although soil heterogeneities strongly influence local response. The macroporous subsurface storm flow zone provides a hydrological pathway for rapid runoff generation apart from the underlying groundwater zone, a conceptualization supported by the two-storage system exhibited by hydrograph recession analysis. A modified version of TOPMODEL is used to simulate the observed catchment dynamics. In this model, generalized topographic index theory is applied to the subsurface storm flow zone to account for logarithmic storm flow recessions, indicative of linearly decreasing transmissivity with depth. Vertical drainage to the groundwater zone is required, and both subsurface reservoirs are considered to contribute to surface saturation.

  20. Microbial iron reduction under deep subsurface pressure conditions

    NASA Astrophysics Data System (ADS)

    Picard, A.; Daniel, I.; Testemale, D.; Hazemann, J.; Oger, P.

    2009-12-01

    The deep subsurface is characterized by hostile conditions in terms of temperature, pressure and nutrient availability. Our current view of the biosphere extension is restricted to depths shallower than the isotherm associated to the highest observed temperature for life, i.e. 122°C. At this temperature, depending on the geological setting, pressure varies between ambient pressure at geothermal springs and 350 MPa in cold subduction zones. In this high-pressure biosphere, biological iron reduction is an important process linked to carbon oxidation. Among the factors governing reaction rates and yields in the deep subsurface, pressure could be of importance due its effects on kinetic and equilibrium reactions. The understanding and modelling of Fe reduction in natural environments, especially in the subsurface, can be first comprehended thanks to studies of Fe reduction in pure cultures; indeed the study of the effects of high pressure on Fe-reducing bacteria in pure cultures can serve as a basic model for the effects of pressure on Fe reduction in the subsurface. We investigated the effects of pressure on the reduction of Fe(III) to Fe(II) by the bacterial model Shewanella oneidensis MR-1. This strain is a mesophilic and piezosensitive counterpart of the psychrophilic and piezophilic Shewanella representatives that have been frequently isolated from deep-sea environments. Kinetics of Fe(III) reduction to Fe(II) were monitored in situ by X-ray Absorption Spectroscopy (XAS) in an appropriate pressure vessel dedicated to in situ XAS measurements (Testemale et al. 2005). Measurements were performed at the BM30B beamline of the European Synchrotron Radiation Facilty (Grenoble, France). Experiments were conducted from 0.1 MPa to 100 MPa at MR-1 optimal temperature (30°C). Iron reduction was monitored until 100 MPa in cultures of MR-1 at a concentration of 10e8 cells/ml. This shows that the metabolic activity of a piezosensitive microbe extends far beyond its pressure

  1. Link between Surface and Subsurface Urban Heat Islands

    NASA Astrophysics Data System (ADS)

    Benz, Susanne; Bayer, Peter; Olesen, Folke; Goettsche, Frank; Blum, Philipp

    2016-04-01

    Urban heat islands exist in all diverse layers of modern cities, such as surface and subsurface. While both layers are typically investigated separately, the coupling of surface and subsurface urban heat islands is insufficiently understood. Hence, this study focuses on the interrelation of both zones and the influence of additional underground heat sources, such as heated basements, on this interaction. Using satellite derived land surface temperatures and interpolated groundwater temperature measurements the spatial properties of both heat islands are compared. Significant correlations of 0.5 up to more than 0.8 are found between surface and subsurface urban heat islands. If groundwater flow is considered this correlation increases by approximately 10%. Next we analyzed the dissimilarities between both heat islands in order to understand the interaction between the urban surface and subsurface. We find that local groundwater hotspots under the city center and industrial areas are not revealed in satellite derived land surface temperatures. Overall groundwater temperatures are higher than land surface temperatures in 95% of the analyzed area due to the influence of below ground anthropogenic heat sources such as sewage systems, district heating systems, and especially elevated basement temperatures. Thus, an estimation method is proposed that relates groundwater temperatures to mean annual land surface temperatures, building density, and elevated basement temperatures. Using this method regional groundwater temperatures can be accurately estimated with a mean absolute error of 0.9 K. Since land surface temperatures and building densities are available from remote sensing, this method has the potential for a large scale estimations of urban groundwater temperatures. Thus, it is feasible to detect subsurface urban heat islands on a global level and to investigate sustainable geothermal potentials using satellite derived data.

  2. Reinventing Government.

    ERIC Educational Resources Information Center

    Osborne, David T.

    1993-01-01

    Throughout all levels of American government, a shift is taking place from the rigid, wasteful, centralized bureaucracies of the industrial era to the more flexible, entrepreneurial, decentralized government needed to succeed in today's world. This shift has been brought about by an unprecedented, ongoing fiscal crisis that has created a sudden…

  3. Remaking Governance.

    ERIC Educational Resources Information Center

    Carver, John

    2000-01-01

    The Policy Governance model's philosophical foundations lie in Rousseau's social contract, Greenleaf's servant-leadership, and modern management theory. Policy Governance stresses primacy of the owner-representative role; full-board authority; superintendents as chief executive officers; authoritative prescription of "ends," bounded…

  4. INEEL Subregional Conceptual Model Report; Volume 1 - Summary of Existing Knowledge of Natural and Anthropogenic Influences Governing Subsurface Contaminant Transport in the INEEL Subregion of the Eastern Snake River Plain

    SciTech Connect

    Wichlacz, Paul Louis; Orr, Brennan

    2002-08-01

    The National Research Council has defined a conceptual model as ''an evolving hypothesis identifying the important features, processes, and events controlling fluid flow and contaminant transport of consequence at a specific field site in the context of a recognized problem''. Presently, several subregional conceptual models are under development at the Idaho National Engineering and Environmental Laboratory (INEEL). Additionally, facility-specific conceptual models have been described as part of INEEL environmental restoration activities. Compilation of these models is required to develop a comprehensive conceptual model that can be used to strategically plan for future groundwater research activities at the INEEL. Conceptual models of groundwater flow and contaminant transport at the INEEL include the description of the geologic framework, matrix hydraulic properties, and inflows and outflows. They also include definitions of the contaminant source term and contaminant transport mechanisms. The geologic framework of the INEEL subregion is described by the geometry of the system, stratigraphic units within the system, and structural features that affect groundwater flow and contaminant transport. These elements define geohydrologic units that make up the Snake River Plain Aquifer (SRPA). The United States Geological Survey (USGS) conceptual model encompasses approximately 1,920 mi2 of the eastern Snake River Plain. The Waste Area Group (WAG)-10 model includes the USGS area and additional areas to the northeast and southeast. Both conceptual models are bounded to the northwest by the Pioneer Mountains, Lost River Range, and Lemhi Mountains. They are bounded to the southeast by groundwater flow paths determined from aquifer water-level contours. The upgradient extent of the USGS model is a water-level contour that includes the northeastern boundary of the INEEL. The WAG-10 model includes more of the Mud Lake area to utilize previous estimates of underflow into the subregion. Both conceptual models extend approximately 25 miles to the southwest of the INEEL, a distance sufficient to include known concentrations of contaminant tracers. Several hypotheses have been developed concerning the effective thickness of the SRPA at the INEEL. The USGS model has defined the effective thickness from electrical resistivity and borehole data to be as much as 2,500 ft in the eastern part of the subregion and as much as 4,000 ft in the southwestern part. The WAG-10 model has developed two alternatives using aquifer-temperature and electrical resistivity data. The ''thick'' aquifer interpretation utilizes colder temperature data and includes a northtrending zone in which the thickness exceeds 1,300 ft and with a maximum thickness of 1,700 ft. The ''thin'' aquifer interpretation minimizes aquifer thickness, with thickness ranging from 328 to 1,300 ft. Facility-specific models generally have focused efforts on the upper 250 ft of saturation. Conceptual models have utilized a stratigraphic data set to define geohydrologic units within the INEEL subregion. This data set, compiled from geophysical logs and cores from boreholes, correlates the thick, complex stack of basalt flows across the subregion. Conceptual models generally concur that the upper geohydrologic unit consists of a section of highly fractured, multiple, thin basalt flows and sedimentary interbeds. Beneath this unit is an areally extensive, thick, unfractured basalt flow that rises above the water table southwest of the INEEL. The bottom unit consists of a thick section of slightly- to moderately-altered basalt. A key objective of the DOE water-integration project at the INEEL is to coordinate development of a subregional conceptual model of groundwater flow and contaminant transport that is based on the best available understanding of geologic and hydrologic features. The first step in this process is to compile and summarize the current conceptual models of groundwater flow and contaminant transport at the INEEL that have been developed from extensive geohydrologic studies conducted during the last 50 years.

  5. Unveiling subsurface hydrogen-bond structure of hexagonal water ice

    NASA Astrophysics Data System (ADS)

    Otsuki, Yuji; Sugimoto, Toshiki; Ishiyama, Tatsuya; Morita, Akihiro; Watanabe, Kazuya; Matsumoto, Yoshiyasu

    2017-09-01

    The phase-resolved sum-frequency-generation (SFG) spectrum for the basal face of hexagonal ice is reported and is interpreted by molecular dynamics simulations combined with ab initio quantum calculations. Here, we demonstrate that the line shape of the SFG spectra of isotope-diluted OH chromophores is a sensitive indicator of structural rumpling uniquely emerging at the subsurface of hexagonal ice. In the outermost subsurface between the first (B1) and second (B2) bilayer, the hydrogen bond of OB 1-H ⋯OB 2 is weaker than that of OB 1⋯H -OB 2 . This implies that subsurface O-O distance is laterally altered, depending on the direction of O-H bond along the surface normal: H-up or H-down, which is in stark contrast to bulk hydrogen bonds. This new finding uncovers how water molecules undercoordinated at the topmost surface influence on the subsurface structural rumpling associated with orientational frustration inherent in water ice.

  6. Mechanisms of Arsenic Mobilization and Attenuation in Subsurface Sediments

    NASA Astrophysics Data System (ADS)

    O'Day, P. A.; Illera, V.; Root, R.; Choi, S.; Vlassopoulos, D.

    2007-12-01

    This talk will review molecular mechanisms of As mobilization and attenuation in subsurface sediments using examples from recent field studies that represent a range in oxidation-redox (redox) potential. As a ubiquitous trace element in sediments, As speciation and fate is linked to the abundance and biogeochemical behavior of the generally more abundant redox-active elements Fe, S, and Mn. All four elements are subject to oxidation, reduction, and pH-dependent processes such as sorption, desorption, precipitation, and dissolution, and which may include both biotic and abiotic reaction steps. We have used spectroscopic interrogation and geochemical modeling to characterize As speciation in subsurface sediments in several contrasting environments, including high and low S and Fe settings. Aquifers most at risk for contamination by As include those that are rich in organic matter and nutrients, stimulating high rates of microbial reduction and creating anoxic conditions, but limited in labile or available S and/or Fe that remove As by precipitation or adsorption. In subsurface sediments with low labile S and Fe, laboratory experiments and spectroscopic studies suggest that sediment Mn minerals are important in the oxidation of sorbed As(III) to As(V), but that they have a limited oxidation capacity. Arsenic attenuation and mobilization in the subsurface are affected by seasonal variations when hydraulic conditions are influenced by surface infiltration, which may induce transitions from oxidized to reduced conditions (or vice versa) in porewater.

  7. Research on subsurface damage of glass-ceramics mirror

    NASA Astrophysics Data System (ADS)

    Peng, Ling-jie; Guo, Pei-ji; Chen, Xi; Wang, Zi-wu

    2016-10-01

    We discuss the depth of subsurface damage (SSD) on different processing conditions. Considering different conditions would produce different depths of SSD, this article seriously studies the depth influenced by different sizes of abrasive particles and different grinding discs. Then the depth of SSD would be detected via Three-Coordinate Measuring Machine (CMM) after traditional polishing. The target of this research is to provide some basic references for the choice of the glass-ceramics grinding machining process.

  8. Partnering to proceed: scaling up adolescent sexual reproductive health programmes in Tanzania. Operational research into the factors that influenced local government uptake and implementation

    PubMed Central

    2010-01-01

    Background Little is known about how to implement promising small-scale projects to reduce reproductive ill health and HIV vulnerability in young people on a large scale. This evaluation documents and explains how a partnership between a non-governmental organization (NGO) and local government authorities (LGAs) influenced the LGA-led scale-up of an innovative NGO programme in the wider context of a new national multisectoral AIDS strategy. Methods Four rounds of semi-structured interviews with 82 key informants, 8 group discussions with 49 district trainers and supervisors (DTS), 8 participatory workshops involving 52 DTS, and participant observations of 80% of LGA-led and 100% of NGO-led meetings were conducted, to ascertain views on project components, flow of communication and decision-making and amount of time DTS utilized undertaking project activities. Results Despite a successful ten-fold scale-up of intervention activities in three years, full integration into LGA systems did not materialize. LGAs contributed significant human resources but limited finances; the NGO retained control over finances and decision-making and LGAs largely continued to view activities as NGO driven. Embedding of technical assistants (TAs) in the LGAs contributed to capacity building among district implementers, but may paradoxically have hindered project integration, because TAs were unable to effectively transition from an implementing to a facilitating role. Operation of NGO administration and financial mechanisms also hindered integration into district systems. Conclusions Sustainable intervention scale-up requires operational, financial and psychological integration into local government mechanisms. This must include substantial time for district systems to try out implementation with only minimal NGO support and modest output targets. It must therefore go beyond the typical three- to four-year project cycles. Scale-up of NGO pilot projects of this nature also need NGOs to be

  9. Phylogenetic relationships among subsurface microorganisms

    SciTech Connect

    Nierzwicki-Bauer, S.A.

    1991-01-01

    This project involves the development of group specific 16S ribosomal RNA-targeted oligonucleotide hybridization probes for the rapid detection of specific types of subsurface organisms (e.g., groups of microbes that share certain physiological traits). Major accomplishments for the period of 6/91 to 12/1/91 are described. Nine new probes have been synthesized on the basis of published 16S rRNA sequence data from the Ribosomal Database Project. We have initiated rapid screening of many of the subsurface microbial isolates obtained from the P24 borehole at the Savannah River Site. To date, we have screened approximately 50% of the isolates from P24. We have optimized our {und in situ} hybridization technique, and have developed a cell blot hybridization technique to screen 96 samples on a single blot. This is much faster than reading 96 individual slides. Preliminary experiments have been carried out which indicate specific nutrients can be used to amplify rRNA only in those organisms capable of metabolizing those nutrients. 1 tab., 2 figs.

  10. Introduction: energy and the subsurface.

    PubMed

    Christov, Ivan C; Viswanathan, Hari S

    2016-10-13

    This theme issue covers topics at the forefront of scientific research on energy and the subsurface, ranging from carbon dioxide (CO2) sequestration to the recovery of unconventional shale oil and gas resources through hydraulic fracturing. As such, the goal of this theme issue is to have an impact on the scientific community, broadly, by providing a self-contained collection of articles contributing to and reviewing the state-of-the-art of the field. This collection of articles could be used, for example, to set the next generation of research directions, while also being useful as a self-study guide for those interested in entering the field. Review articles are included on the topics of hydraulic fracturing as a multiscale problem, numerical modelling of hydraulic fracture propagation, the role of computational sciences in the upstream oil and gas industry and chemohydrodynamic patterns in porous media. Complementing the reviews is a set of original research papers covering growth models for branched hydraulic crack systems, fluid-driven crack propagation in elastic matrices, elastic and inelastic deformation of fluid-saturated rock, reaction front propagation in fracture matrices, the effects of rock mineralogy and pore structure on stress-dependent permeability of shales, topographic viscous fingering and plume dynamics in porous media convection.This article is part of the themed issue 'Energy and the subsurface'.

  11. Sulfur and iron cycling in deep-subsurface, coal bed-containing sediments off Shimokita (Japan)

    NASA Astrophysics Data System (ADS)

    Riedinger, N.; Smirnoff, M. N.; Gilhooly, W.; Phillips, S. C.; Lyons, T. W.; 337 Scientific Party, I.

    2013-12-01

    The main goal of IODP Expedition 337 was the identification and characterization of the deep coal bed biosphere and hydrocarbon system off the Shimokita Peninsula (Japan) in the northwestern Pacific using the D/V Chikyu. To accomplish this scientific objective, it was also necessary to investigate the inorganic biogeochemistry in order to identify possible electron acceptors and bio-essential nutrients. These biogeochemical parameters greatly influence both, the composition and abundance of microbial communities as well as the organic carbon cycle. In turn, the microbially mediated carbon cycle influences the diagenetic reactions in the subsurface, thus, altering geochemical and physical characteristics of the material. Here we present results from metal and sulfur geochemical analyses from the deep-subsurface sediments (about 1250 to 2466 mbsf) at Site C0020 off Shimokita. The measured concentrations of acid volatile sulfur (AVS) as well as chromium reducible sulfur (CRS) reflect the alteration of iron oxides to iron sulfides and indicate that the main sulfur-bearing phase in the investigated sediments is pyrite. Concentrations of intermediate sulfur species are minor and occur mainly in the coal-bearing interval. Our data show that the uppermost sediments contain higher amounts of pyrite (up to 1.2 wt.%) with an average of 0.5 wt.% compared to the deeper deposits (below about 1800 mbsf), which show an average of 0.16 wt.%. In contrast, iron oxide concentrations are highest in the deeper sediment sections (up to 0.4%), where pyrite concentrations are low. The alteration of iron oxides to sulfides in theses lower section was probably governed by the amount of available sulfide in the pore water. The occurrence of (bio-)reactive iron phases in these deeply buried sediments has implications for the deep biosphere as those minerals have the potential to serve as electron acceptors during burial, including reactions involving deep sourced electron donors, such as

  12. STOMP, Subsurface Transport Over Multiple Phases, theory guide

    SciTech Connect

    White, M.D.; Oostrom, M.

    1996-10-01

    This guide describes the simulator`s governing equations, constitutive functions and numerical solution algorithms of the STOMP (Subsurface Transport Over Multiple Phases) simulator, a scientific tool for analyzing multiple phase subsurface flow and transport. The STOMP simulator`s fundamental purpose is to produce numerical predictions of thermal and hydrologic flow and transport phenomena in variably saturated subsurface environments, which are contaminated with volatile or nonvolatile organic compounds. Auxiliary applications include numerical predictions of solute transport processes including radioactive chain decay processes. In writing these guides for the STOMP simulator, the authors have assumed that the reader comprehends concepts and theories associated with multiple-phase hydrology, heat transfer, thermodynamics, radioactive chain decay, and nonhysteretic relative permeability, saturation-capillary pressure constitutive functions. The authors further assume that the reader is familiar with the computing environment on which they plan to compile and execute the STOMP simulator. The STOMP simulator requires an ANSI FORTRAN 77 compiler to generate an executable code. The memory requirements for executing the simulator are dependent on the complexity of physical system to be modeled and the size and dimensionality of the computational domain. Likewise execution speed depends on the problem complexity, size and dimensionality of the computational domain, and computer performance. One-dimensional problems of moderate complexity can be solved on conventional desktop computers, but multidimensional problems involving complex flow and transport phenomena typically require the power and memory capabilities of workstation or mainframe type computer systems.

  13. 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

  14. Microbial processes and subsurface contaminants

    NASA Astrophysics Data System (ADS)

    Molz, Fred J.

    A Chapman Conference entitled “Microbial Processes in the Transport, Fate, and In Situ Treatment of Subsurface Contaminants” was held in Snowbird, Utah, October 1-3, 1986. Members of the program committee and session chairmen were Lenore Clesceri (Rensselaer Polytechnic Institute, Troy, N.Y.), David Gibson (University of Texas, Austin), James Mercer (GeoTrans, Inc., Herndon , Va.), Donald Michelsen (Virginia Polytechnic Institute and State University, Blacksburg), Fred Molz (Auburn University, Auburn, Ala.), Bruce Rittman (University of Illinois, Urbana), Gary Sayler (University of Tennessee, Knoxville), and John T. Wilson (U.S. Environmental Protection Agency, Ada, Okla.). The following report attempts to highlight the six sessions that constituted the conference. For additional information, including a bound summary and abstracts, contact Fred J. Molz, Civil Engineering Department, Auburn University, AL 36849 (telephone: 205-826-4321).

  15. Subsurface drainage processes and management impacts

    Treesearch

    Elizabeth T. Keppeler; David Brown

    1998-01-01

    Storm-induced streamflow in forested upland watersheds is linked to rainfall by transient, variably saturated flow through several different flow paths. In the absence of exposed bedrock, shallow flow-restrictive layers, or compacted soil surfaces, virtually all of the infiltrated rainfall reaches the stream as subsurface flow. Subsurface runoff can occur within...

  16. 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

  17. Key aspects governing induced seismicity

    NASA Astrophysics Data System (ADS)

    Buijze, Loes; Wassing, Brecht; Fokker, Peter

    2013-04-01

    In the past decades numerous examples of earthquakes induced by human-induced changes in subsurface fluid pressures have been reported. This poses a major threat to the future development of some of these operations and calls for an understanding and quantification of the seismicity generated. From geomechanical considerations and insights from laboratory experiments the factors controlling induced seismicity may be grouped into 4 categories; the magnitude of the stress disturbance, the pre-existing stress conditions, the reservoir/fault rock properties and the local geometry. We investigated whether the (relative) contributions of these factors and their influence on magnitudes generated could be recognized by looking at the entire dataset of reported cases of induced seismicity as a whole, and what this might imply for future developments. An extensive database has been built out of over a 160 known cases of induced seismicity worldwide, incorporating the relevant geological, seismological and fluid-related parameters. The cases studied include hydrocarbon depletion and secondary recovery, waste water injection, (enhanced) geothermal systems and hydraulic fracturing with observed magnitudes ranging from less than -1.5 to 7. The parameters taken into account were based on the theoretical background of the mechanisms of induced seismicity and include the injection/depletion-related parameters, (spatial) characteristics of seismicity, lithological properties and the local stress situation. Correlations between the seismic response and the geological/geomechanical characteristics of the various sites were investigated. The injected/depleted volumes and the scale of the activities are major controlling factors on the maximum magnitudes generated. Spatial signatures of seismicity such as the depth and lateral spread of the seismicity were observed to be distinct for different activities, which is useful when considering future operations. Where available the local

  18. Surface expressions of subsurface structures in parts of the Michigan and Illinois basins

    SciTech Connect

    Herman, J.D. )

    1991-08-01

    Study of glacial geology, stream drainage, bedrock topography, and subsurface structure maps in Isabella, Midland, Arenac, Gladwin, Clare, Ogemaw, Iosco, Mecosta, and Montcalm counties in Michigan revealed distinct correlations between patterns and types of glacial deposits and subsurface structures. Anticlinal structures associated with the Mt. Pleasant, North Buckeye, and South Buckeye, Hamilton, Deep River, Clayton, Logan, Six Lakes, and West Branch oil and gas fields occur along areas where northeast-trending glacial moraines and truncated, attenuated, or deviated. Furthermore, these anticlinal structures are associated with lacustrine sands and gravels and glacial outwash deposits nearly surrounded by glacial tills or lacustrine sands and clays. All of the anticlinal structures are associated with bedrock topography highs and alignment of streams parallel to the trends of the structures. Comparison of images of subsurface structure and surface elevation data covering the northern part of the illinois basin showed distinct correlations between glacial moraine patterns and subsurface structural trends. The Pesotum and Arcola end moraines bracket the major anticlinal structure at the Hayes oil field. The Westfield, Nevins, and Paris moraines are truncated or attenuated where they intersect the surface projections of the subsurface LaSalle anticlinal belt and the anticlinal structure associated with the Mattoon oil field. These correlations among subsurface structure, bedrock topography, and surface glacial features indicate that the subsurface structural configuration influenced glacial depositional patterns in detectable and predictable ways, even in areas blanketed by over 100 ft of Wisconsin glacial drift.

  19. Government Regulatory

    NASA Astrophysics Data System (ADS)

    Becker, Katie

    Government regulation of food products, food processing, and food preparation is imperative in bringing an unadulterated, nonmisleading, and safe food product to market and is relevant to all areas of food science, including engineering, processing, chemistry, and microbiology. The liability associated with providing consumers with an adulterated or substandard product cannot only tarnish a company's name and reputation, but also impose substantial financial repercussions on the company and those individuals who play an active role in the violation. In order for a company to fully comply with the relevant food laws (both federal and state), an intimate knowledge of food science is required. Individuals knowledgeable in food science play an integral role not only in implementing and counseling food companies/processors to ensure compliance with government regulations, but these individuals are also necessary to the state and federal governments that make and enforce the relevant laws and regulators.

  20. A review on nitrogen and organics removal mechanisms in subsurface flow constructed wetlands: dependency on environmental parameters, operating conditions and supporting media.

    PubMed

    Saeed, Tanveer; Sun, Guangzhi

    2012-12-15

    With the unique advantages of lower operational and maintenance cost, the applications of subsurface flow constructed wetlands for the treatment of wastewater have been increasing rapidly throughout the world. The removal of nitrogen and organics by such systems has gained substantial attention in recent years. In subsurface flow wetlands, the removal of pollutants often relies on a diverse range of co-existing physical, chemical and biological routes, which are vitally dependent on numerous environmental and operational parameters. This paper provides a comprehensive review of wetland structures, classic and novel nitrogen and organics removal mechanisms along with the key environmental parameters and operational conditions that enhance removal in subsurface flow wetland systems. The critical exploration identifies the major environmental parameters such as: pH, DO, and temperature, operational factors i.e. organic carbon availability, loading, feed mode, retention time, recirculation, harvesting, and the complex role (of both parameters) on classical nitrogen and organics removal pathways. Subsequently, the necessity of further extensive research on such factors, for promoting novel nitrogen removal routes in wetland systems has also been highlighted. The expansion of the review on the influence of the unconventional wetland matrix indicates that, the structural differences and inherent properties of these media can support substantial nitrogen and organics removal from wastewater, under optimal operating conditions. Overall, the critical review illustrates the necessity of a profound knowledge on the complicated inter-relationship between nitrogen and organics removal routes, governing environmental and operational parameters, and wetland matrix for improving the treatment performances of subsurface flow wetlands.

  1. Subsurface-structure determination using photothermal laser-beam deflection

    NASA Astrophysics Data System (ADS)

    Wetsel, Grover C., Jr.; McDonald, F. Alan

    1982-11-01

    Photothermal imaging using laser-beam deflection is shown to be a successful means of detecting subsurface structure in solids. Experimental data for known and unknown subsurface structures are reported. The existing theory agrees well with data on broad subsurface structures, but small subsurface structures produce signal variations which are better represented by a subsurface thermal contact resistance. The first photothermal-image characterization of a microscopic, unknown subsurface defect is presented.

  2. The thermal impact of subsurface building structures on urban groundwater resources - A paradigmatic example.

    PubMed

    Epting, Jannis; Scheidler, Stefan; Affolter, Annette; Borer, Paul; Mueller, Matthias H; Egli, Lukas; García-Gil, Alejandro; Huggenberger, Peter

    2017-10-15

    Shallow subsurface thermal regimes in urban areas are increasingly impacted by anthropogenic activities, which include infrastructure development like underground traffic lines as well as industrial and residential subsurface buildings. In combination with the progressive use of shallow geothermal energy systems, this results in the so-called subsurface urban heat island effect. This article emphasizes the importance of considering the thermal impact of subsurface structures, which commonly is underestimated due to missing information and of reliable subsurface temperature data. Based on synthetic heat-transport models different settings of the urban environment were investigated, including: (1) hydraulic gradients and conductivities, which result in different groundwater flow velocities; (2) aquifer properties like groundwater thickness to aquitard and depth to water table; and (3) constructional features, such as building depths and thermal properties of building structures. Our results demonstrate that with rising groundwater flow velocities, the heat-load from building structures increase, whereas down-gradient groundwater temperatures decrease. Thermal impacts on subsurface resources therefore have to be related to the permeability of aquifers and hydraulic boundary conditions. In regard to the urban settings of Basel, Switzerland, flow velocities of around 1 md(-1) delineate a marker where either down-gradient temperature deviations or heat-loads into the subsurface are more relevant. Furthermore, no direct thermal influence on groundwater resources should be expected for aquifers with groundwater thicknesses larger 10m and when the distance of the building structure to the groundwater table is higher than around 10m. We demonstrate that measuring temperature changes down-gradient of subsurface structures is insufficient overall to assess thermal impacts, particularly in urban areas. Moreover, in areas which are densely urbanized, and where groundwater flow

  3. Surface Hydrogen and Subsurface Hydrogen: Their Roles in Bulk Absorption and Surface Reaction

    NASA Astrophysics Data System (ADS)

    Fukutani, Katsuyuki

    Hydrogen adsorbed on metal surfaces possibly penetrates into “subsurface” sites, which might further diffuse into bulk. When temperature is raised, on the other hand, such absorbed hydrogen diffuses back to the surface via the subsurface site eventually desorbing from the surface. The kinetics of these absorption and desorption are ideally expressed by the potential energy surfaces of hydrogen near the surfaces. This article describes how the potential of hydrogen is described, and how the surface and subsurface sites influence the kinetics of absorption and desorption for Pd and Ni as examples. As well as these phenomena, the subsurface sites could serve to promote particular hydrogenation reactions occurring at surfaces. The mechanism of subsurface chemistry is discussed.

  4. Metal resistance among aerobic chemoheterotrophic bacteria from the deep terrestrial subsurface.

    PubMed

    Benyehuda, G; Coombs, J; Ward, P L; Balkwill, D; Barkay, T

    2003-02-01

    The metal resistance of 350 subsurface bacterial strains from two U.S. Department of Energy facilities, the Savannah River Site (SRS), South Carolina, and the Hanford site, Washington, was determined to assess the effect of metal toxicity on microorganisms in the deep terrestrial subsurface. Resistance was measured by growth inhibition around discs containing optimized amounts of Hg(II), Pb(II), and Cr(VI). A broad range of resistance levels was observed, with some strains of Arthrobacter spp. demonstrating exceptional tolerance. A higher level of resistance to Hg(II) and Pb(II) (P < 0.05) and a higher occurrence of multiple resistances suggested that metals more effectively influenced microbial evolution in subsurface sediments of the SRS than in those of the Hanford site. Common resistance to heavy metals suggests that toxic metals are unlikely to inhibit bioremediation in deep subsurface environments that are contaminated with mixed wastes.

  5. Solar subsurface flows from local helioseismology

    NASA Astrophysics Data System (ADS)

    Zhao, Junwei; Chen, Ruizhu

    2016-07-01

    In this article, we review recent progresses in subsurface flows obtained from two local helioseismology methods: time-distance helioseismology and ring-diagram analysis. We review results in the following four topics: flows beneath sunspots and active regions, supergranular subsurface flows, shallow meridional flow and its variations with solar cycles, and meridional circulation in the deep solar interior. Despite recent advancements in methodology, modeling, and observations, many questions are still to be answered and a few topics remain controversial. More efforts, especially in numerical modeling and accurate interpretation of acoustic wave travel-time measurements, are needed to improve the derivations of subsurface flows.

  6. Using soil moisture and spatial yield patterns to identify subsurface flow pathways.

    PubMed

    Gish, T J; Walthall, C L; Daughtry, C S T; Kung, K-J S

    2005-01-01

    Subsurface soil water dynamics can influence crop growth and the fate of surface-applied fertilizers and pesticides. Recently, a method was proposed using only ground-penetrating radar (GPR) and digital elevation maps (DEMs) to identify locations where subsurface water converged into discrete pathways. For this study, the GPR protocol for identifying horizontal subsurface flow pathways was extended to a 3.2-ha field, uncertainty is discussed, and soil moisture and yield patterns are presented as confirming evidence of the extent of the subsurface flow pathways. Observed soil water contents supported the existence of discrete preferential funnel flow processes occurring near the GPR-identified preferential flow pathways. Soil moisture also played a critical role in the formation of corn (Zea mays L.) grain yield patterns with yield spatial patterns being similar for mild and severe drought conditions. A buffer zone protocol was introduced that allowed the impact of subsurface flow pathways on corn grain yield to be quantified. Results indicate that when a GPR-identified subsurface clay layer was within 2 m of the soil surface, there was a beneficial impact on yield during a drought year. Furthermore, the buffer zone analysis demonstrated that corn grain yields decreased as the horizontal distance from the GPR-identified subsurface flow pathways increased during a drought year. Averaged real-time soil moisture contents at 0.1 m also decreased with increasing distance from the GPR-identified flow pathways. This research suggests that subsurface flow pathways exist and influence soil moisture and corn grain yield patterns.

  7. Subsurface Explosions in Granular Media

    NASA Astrophysics Data System (ADS)

    Lai, Shuyue; Houim, Ryan; Oran, Elaine

    2015-11-01

    Numerical simulations of coupled gas-granular flows are used to study properties of shock formation and propagation in media, such as sand or regolith on the moon, asteroids, or comets. The simulations were performed with a multidimensional fully compressible model, GRAF, which solves two sets of coupled Navier-Stokes equations, one for the gas and one for the granular medium. The specific case discussed here is for a subsurface explosion in a granular medium initiated by an equivalent of 200g of TNT in depths ranging from 0.1m to 3m. The background conditions of 100K, 10 Pa and loose initial particle volume fraction of 25% are consistent with an event on a comet. The initial blast creates a cavity as a granular shock expands outwards. Since the gas-phase shock propagates faster than the granular shock in loose, granular material, some gas and particles are ejected before the granular shock arrives. When the granular shock reaches the surface, a cap-like structure forms. This cap breaks and may fall back on the surface and in this process, relatively dense particle clusters form. At lower temperatures, the explosion timescales are increased and entrained particles are more densely packed.

  8. Introduction: energy and the subsurface

    PubMed Central

    Viswanathan, Hari S.

    2016-01-01

    This theme issue covers topics at the forefront of scientific research on energy and the subsurface, ranging from carbon dioxide (CO2) sequestration to the recovery of unconventional shale oil and gas resources through hydraulic fracturing. As such, the goal of this theme issue is to have an impact on the scientific community, broadly, by providing a self-contained collection of articles contributing to and reviewing the state-of-the-art of the field. This collection of articles could be used, for example, to set the next generation of research directions, while also being useful as a self-study guide for those interested in entering the field. Review articles are included on the topics of hydraulic fracturing as a multiscale problem, numerical modelling of hydraulic fracture propagation, the role of computational sciences in the upstream oil and gas industry and chemohydrodynamic patterns in porous media. Complementing the reviews is a set of original research papers covering growth models for branched hydraulic crack systems, fluid-driven crack propagation in elastic matrices, elastic and inelastic deformation of fluid-saturated rock, reaction front propagation in fracture matrices, the effects of rock mineralogy and pore structure on stress-dependent permeability of shales, topographic viscous fingering and plume dynamics in porous media convection. This article is part of the themed issue ‘Energy and the subsurface’. PMID:27597784

  9. Fluid-powered subsurface pump

    SciTech Connect

    Gipson, T.C.

    1991-12-03

    This paper describes a fluid-powered pump for attachment to small diametered coiled tubing for pumping subsurface liquid from a well production tube. It comprises: a pump housing having an upper end and a lower end, the upper end releasably attachable to a downhole end of the coiled tubing, the inside of the upper end of the housing in fluid communication with the inside of the coiled tubing; a cross head seal member dividing the pump into an upper chamber and a lower chamber, the upper chamber in fluid communication with the inside of the coiled tubing; a pump actuator extending between the upper and lower chambers, the actuator having an upper piston head sealingly fitted to reciprocate in the upper chamber and a lower piston head sealingly fitted to reciprocate in the lower chamber, the upper piston head and the lower piston head connected to each other by a connector rod sealing slidable in the cross head seal member, the actuator having a conduit for fluid communication between the upper chamber and the lower chamber, the conduit extending from an orifice in the top surface of the upper piston head, through the connector rod to a port above the top surface of the lower piston head.

  10. Surface and subsurface decontamination technology

    SciTech Connect

    Tuck, Matt; Wray, Beth; Musgrave, Mark

    2013-07-01

    A number of proven technologies applicable to the chemical and physical decontamination of radioactive and non-radioactive contaminants within the environmental remediation and radiological waste management sectors exist. Previous work generally acknowledges that these methods have limitations such as production of large volumes of waste, destruction of the substrate, complex safety considerations [1a] and application of special precautions to meet disposal acceptance criteria [2]. A method that removes a variety of contaminants from the surface and subsurface of porous materials, with minimal contaminated waste arisings, is highly desirable. TechXtract{sup R} is a patented, sequential chemical extraction process developed to remove radionuclides, PCBs, and other hazardous organic and inorganic substances from solid materials such as concrete, brick, steel, and exotic metals [3]. The technology uses multifarious task-specific chemical formulations and engineered applications to achieve surface penetration and removal of the contaminants from the atomic voids of metals and other substrates, or the capillaries and gel pores of concretes. TechXtract{sup R} is proven to remove a variety of contaminants from various substrates, allowing free release of the substrate as waste for disposal, or re-use, whilst producing minimal secondary waste. Data from testing of TechXtract's capabilities and evidencing the technology's efficacy during site based applied research and development is presented here. (authors)

  11. Disjointed Governance in University Centers and Institutes

    ERIC Educational Resources Information Center

    Mallon, William

    2004-01-01

    Research centers and institutes are one example of how institutional governance has become increasingly disjointed; as the "suburbs" of the university expand, core governance structures lose influence. (Contains 1 table and 1 figure.)

  12. Subsurface Biogeochemical Research FY11 Second Quarter Performance Measure

    SciTech Connect

    Scheibe, Timothy D.

    2011-03-31

    The Subsurface Biogeochemical Research (SBR) Long Term Measure for 2011 under the Performance Assessment Rating Tool (PART) measure is to "Refine subsurface transport models by developing computational methods to link important processes impacting contaminant transport at smaller scales to the field scale." The second quarter performance measure is to "Provide a report on computational methods linking genome-enabled understanding of microbial metabolism with reactive transport models to describe processes impacting contaminant transport in the subsurface." Microorganisms such as bacteria are by definition small (typically on the order of a micron in size), and their behavior is controlled by their local biogeochemical environment (typically within a single pore or a biofilm on a grain surface, on the order of tens of microns in size). However, their metabolic activity exerts strong influence on the transport and fate of groundwater contaminants of significant concern at DOE sites, in contaminant plumes with spatial extents of meters to kilometers. This report describes progress and key findings from research aimed at integrating models of microbial metabolism based on genomic information (small scale) with models of contaminant fate and transport in aquifers (field scale).

  13. Uranium Biomineralization By Natural Microbial Phosphatase Activities in the Subsurface

    SciTech Connect

    Taillefert, Martial

    2015-04-01

    This project investigated the geochemical and microbial processes associated with the biomineralization of radionuclides in subsurface soils. During this study, it was determined that microbial communities from the Oak Ridge Field Research subsurface are able to express phosphatase activities that hydrolyze exogenous organophosphate compounds and result in the non-reductive bioimmobilization of U(VI) phosphate minerals in both aerobic and anaerobic conditions. The changes of the microbial community structure associated with the biomineralization of U(VI) was determined to identify the main organisms involved in the biomineralization process, and the complete genome of two isolates was sequenced. In addition, it was determined that both phytate, the main source of natural organophosphate compounds in natural environments, and polyphosphate accumulated in cells could also be hydrolyzed by native microbial population to liberate enough orthophosphate and precipitate uranium phosphate minerals. Finally, the minerals produced during this process are stable in low pH conditions or environments where the production of dissolved inorganic carbon is moderate. These findings suggest that the biomineralization of U(VI) phosphate minerals is an attractive bioremediation strategy to uranium bioreduction in low pH uranium-contaminated environments. These efforts support the goals of the SBR long-term performance measure by providing key information on "biological processes influencing the form and mobility of DOE contaminants in the subsurface".

  14. Evaluation of subsurface oxygen sensors for remediation monitoring

    SciTech Connect

    Li, D.X.; Lundegard, P.D.

    1996-05-01

    Continuous remediation monitoring using sensors is potentially a more effective and inexpensive alternative to current methods of sample collection and analysis. Gaseous components of a system are the most mobile and easiest to monitor. Continuous monitoring of soil gases such as oxygen, carbon dioxide, and contaminant vapors can provide important quantitative information regarding the progress of bioremediation efforts and the area of influence of air sparging or soil venting. Laboratory and field tests of a commercially available oxygen sensor show that the subsurface oxygen sensor provides rapid and accurate data on vapor phase oxygen concentrations. The sensor is well suited for monitoring gas flow and oxygen consumption in the vadose zone during air sparging and bioventing. The sensor performs well in permeable, unsaturated soil environments and recovers completely after being submerged during temporary saturated conditions. Calibrations of the in situ oxygen sensors were found to be stable after one year of continuous subsurface operation. However, application of the sensor in saturated soil conditions is limited. The three major advantages of this sensor for in situ monitoring are as follows: (1) it allows data acquisition at any specified time interval; (2) it provides potentially more accurate data by minimizing disturbance of subsurface conditions; and (3) it minimizes the cost of field and laboratory procedures involved in sample retrieval and analysis.

  15. DOE UST interim subsurface barrier technologies workshop

    SciTech Connect

    1992-09-01

    This document contains information which was presented at a workshop regarding interim subsurface barrier technologies that could be used for underground storage tanks, particularly the tank 241-C-106 at the Hanford Reservation.

  16. Component-Based Framework for Subsurface Simulations

    SciTech Connect

    Palmer, Bruce J.; Fang, Yilin; Hammond, Glenn E.; Gurumoorthi, Vidhya

    2007-08-01

    Simulations in the subsurface environment represent a broad range of phenomena covering an equally broad range of scales. Developing modelling capabilities that can integrate models representing different phenomena acting at different scales present formidable challenges both from the algorithmic and computer science perspective. This paper will describe the development of an integrated framework that will be used to combine different models into a single simulation. Initial work has focused on creating two frameworks, one for performing smooth particle hydrodynamics (SPH) simulations of fluid systems, the other for performing grid-based continuum simulations of reactive subsurface flow. The SPH framework is based on a parallel code developed for doing pore scale simulations, the continuum grid-based framework is based on the STOMP (Subsurface Transport Over Multiple Phases) code developed at PNNL. Future work will focus on combining the frameworks together to perform multiscale, multiphysics simulations of reactive subsurface flow.

  17. SUBSURFACE REPOSITORY INTEGRATED CONTROL SYSTEM DESIGN

    SciTech Connect

    D.C. Randle

    2000-01-07

    The primary purpose of this document is to develop a preliminary high-level functional and physical control system architecture for the potential repository at Yucca Mountain. This document outlines an overall control system concept that encompasses and integrates the many diverse process and communication systems being developed for the subsurface repository design. This document presents integrated design concepts for monitoring and controlling the diverse set of subsurface operations. The Subsurface Repository Integrated Control System design will be composed of a series of diverse process systems and communication networks. The subsurface repository design contains many systems related to instrumentation and control (I&C) for both repository development and waste emplacement operations. These systems include waste emplacement, waste retrieval, ventilation, radiological and air monitoring, rail transportation, construction development, utility systems (electrical, lighting, water, compressed air, etc.), fire protection, backfill emplacement, and performance confirmation. Each of these systems involves some level of I&C and will typically be integrated over a data communications network throughout the subsurface facility. The subsurface I&C systems will also interface with multiple surface-based systems such as site operations, rail transportation, security and safeguards, and electrical/piped utilities. In addition to the I&C systems, the subsurface repository design also contains systems related to voice and video communications. The components for each of these systems will be distributed and linked over voice and video communication networks throughout the subsurface facility. The scope and primary objectives of this design analysis are to: (1) Identify preliminary system-level functions and interfaces (Section 6.2). (2) Examine the overall system complexity and determine how and on what levels the engineered process systems will be monitored, controlled, and

  18. Evaluating Subsurface Damage in Optical Glasses

    NASA Astrophysics Data System (ADS)

    Lee, Y.

    2011-02-01

    Hard brittle materials (e.g. glasses and ceramics) increasingly appeal to general interests because of their excellent physical, mechanical and chemical properties such as super hardness and strength at extreme temperature and chemical stability. The precision manufacturing of these materials is primarily achieved by grinding and polishing, which generally employs abrasives to wear the materials. With this manufacturing technology, the materials are removed due principally to the fracture of brittle materials, which will leave a cracked layer on the surface of manufactured components, namely subsurface damage (SSD). The subsurface damage affects the strength, performance and lifetime of components. As a result, investigation into the subsurface damage is needed. A host of characterizing techniques have been developed during the past several decades. These techniques based on different mechanisms provide researchers with invaluable information on the subsurface damage in various materials. In this article the typical SSD evaluation techniques are reviewed, which are regularly used in optical workshops or laboratories.

  19. Subsurface application enhances benefits of manure redistribution

    USDA-ARS?s Scientific Manuscript database

    Sustainable nutrient management requires redistribution of livestock manure from nutrient-excess areas to nutrient-deficit areas. Field experiments were conducted to assess agronomic and environmental effects of different poultry litter application methods (surface vs. subsurface) and timings (fall ...

  20. Use of radar for nonintrusive subsurface investigations

    SciTech Connect

    1995-07-01

    Finding and mapping buried hazardous waste can be a time-consuming process. However, advances in ground-penetrating radar technology are improving the means by which to detect subsurface features and related contamination. Geophysical Survey Systems, Inc. (North Salem, New Hampshire) has developed an innovative ground-penetrating radar system. The Subsurface Interface Radar (SIR{reg_sign}) system can provide real-time and continuous-profile records that indicate the location and depth of objects within subsurfaces of soil, concrete, rock, water, or other dielectric materials. The SIR{reg_sign} system allows the user to investigate subsurface conditions in a nonintrusive manner; this radar can locate underground storage tanks and buried drums, delineate landfill boundaries and burial trenches, and in some cases, the radar can identify hydrocarbon plums.

  1. MODELING CONTAMINANT TRANSPORT THROUGH SUBSURFACE SYSTEMS

    EPA Science Inventory

    Modeling of contaminant transport through soil to groundwater to a receptor requires that consideration be given to the many processes which control the transport and fate of chemical constituents in the subsurface environment. These processes include volatilization, degradation,...

  2. Crater Formed in 2008 Reveals Subsurface Ice

    NASA Image and Video Library

    2009-09-24

    The High Resolution Imaging Science Experiment camera on NASA Mars Reconnaissance Orbiter reveals subsurface ice in a crater formed in 2008. The impact that dug the crater excavated water ice from beneath the surface.

  3. Site characterization and remediation monitoring using in situ subsurface sensors

    SciTech Connect

    Li, D.X.

    1995-09-01

    Site characterization and remediation monitoring using in situ sensors is potentially a more effective and inexpensive alternative to current methods of sample collection and analysis. Gaseous components of a system are the most mobile and easiest to monitor. Soil gas measurements can not only indicate the presence of hydrocarbon contamination, but also provide important quantitative information regarding the progress of bioremediation efforts and the area of influence of air sparging or soil venting. In situ subsurface sensors can provide potentially more accurate data by minimizing disturbance of subsurface conditions and allow continuous and unattended measurements over a long period of time. Tests of in situ soil gas sensors show that the sensors provide rapid and accurate data on soil gas pressures and vapor phase concentrations. The sensors perform well in permeable, unsaturated soil environments and recover completely after being submerged during temporary saturated conditions. The pressure and subsurface oxygen sensors are well suited for monitoring gas flow and oxygen consumption in the vadose zone during air sparging and bioventing. These sensors have been used to develop a new dynamic technique of evaluating in situ respiration rates during air injection or vapor extraction which has several advantages over the traditional static oxygen uptake method. By using a subsurface oxygen sensor, the dynamic technique offers continuous monitoring capability during the bioventing process. Unlike the traditional respiration test that measures localized respiration rates, this method determines an average respiration rate in the air flow path. Because the measurements can be made at the startup of a remediation process, the operation can run without interruption.

  4. Microbial life in the deep terrestrial subsurface

    SciTech Connect

    Fliermans, C.B.; Balkwill, D.L.; Beeman, R.E.

    1988-12-31

    The distribution and function of microorganisms is a vital issue in microbial ecology. The US Department of Energy`s Program, ``Microbiology of the Deep Subsurface,`` concentrates on establishing fundamental scientific information about organisms at depth, and the use of these organisms for remediation of contaminants in deep vadose zone and groundwater environments. This investigation effectively extends the Biosphere hundreds of meters into the Geosphere and has implications to a variety of subsurface activities.

  5. Floating insulated conductors for heating subsurface formations

    DOEpatents

    Burns, David; Goodwin, Charles R.

    2014-07-29

    A heating system for a subsurface formation includes a conduit located in a first opening in the subsurface formation. Three electrical conductors are located in the conduit. A return conductor is located inside the conduit. The return conductor is electrically coupled to the ends of the electrical conductors distal from the surface of the formation. Insulation is located inside the conduit. The insulation electrically insulates the three electrical conductors, the return conductor, and the conduit from each other.

  6. Mathematical Modeling of the Subsurface Behavior of Quantum Dot Nanoparticles in the Presence of Stabilizing Polymers

    NASA Astrophysics Data System (ADS)

    Becker, M. D.; Wang, Y.; Pennell, K. D.; Abriola, L. M.

    2011-12-01

    As the manufacture and use of nanomaterials become more prevalent, the development of mathematical models capable of predicting nanomaterial transport and retention in subsurface systems is crucial to assessing their environmental fate. To enhance aqueous solubility, nanoparticle production often involves the use of a surfactant or other stabilizing agent. The presence of stabilizing agents, whether natural or synthetic, could significantly influence nanoparticle mobility and fate in the subsurface. In this study, quantum dot (QD) mobility experiments were performed in columns packed with three size fractions of Ottawa sand (d50 = 125, 165, and 335 μm) at two different pore-water velocities (0.8 m/d and 7.6 m/d). The QDs synthesized for these experiments consisted of a CdSe core embedded in a CdZnS shell with a poly(acrylic acid)-octylamine (PAA) coating to promote suspension stability. The QDs were negatively charged (measured zeta potential ca. -35 mV) with a hydrodynamic diameter of approximately 30 nm. Experimental observations consistently revealed low amounts of QD deposition near the column inlet, results that were inconsistent with expectations based upon clean bed filtration theory. This phenomenon was hypothesized to be related to competitive adsorption of residual aqueous PAA to the sand surface. A systematic modeling approach was undertaken to explore mechanisms controlling the transport and deposition of QDs in the presence of competitively adsorbing aqueous PAA. The model incorporated a coupled system of equations governing the fate and transport of both nanoparticles and chemical additives. QD retention was described using a modification of a traditional clean bed filtration governing equation that assumes irreversible first-order attachment and incorporates a maximum or limiting retention capacity. Simultaneous transport and adsorption of PAA were modeled using a traditional advection-dispersion-reaction equation that incorporates a first

  7. Prevention practices influencing frequency of occurrence of vaso-occlusive crisis among sickle cell patients in Abeokuta South Local Government Area of Ogun State, Nigeria.

    PubMed

    Amoran, Olorunfemi Emmanuel; Jimoh, Ahmed Babatunde; Ojo, Omotola; Kuponiyi, Temitope

    2017-01-01

    Africa is the most affected continent with 200,000 new born affected by sickle cell anemia annually with of 5% of under five deaths. Nigeria has the largest sickle cell gene pool in the world with about 2% of all babies born to Nigerian parents. This study therefore sets out to assess the prevention practices influencing the frequency of occurrence of vaso-occlusive crisis among patients in Ogun State. This study is a descriptive cross-sectional study conducted in Abeokuta South Local Government Area Ogun State. A consecutive non randomized sampling of all the sickle cell patients that attend the selected facilities was recruited into the study. Data were collected with the use of questionnaires which were interviewer administered. A total of 415 patients were recruited into the study. Statistical analyses were conducted using SPSS for Windows version 20.0. Two- third [64.8%] of study participants have crisis twice or more in a month. The frequency of crisis was statistically significantly associated with the age of the child [p = 0.006], use of anti-malaria prophylaxis [p = 0.006], analgesics [p = 0.0001], taking of plenty fluid [p = 0.001] and soothing herbs [p = 0.0001]. Lifestyle factors such as giving balance diet [p = 0.217], restriction from strenuous activities [p = 0.08], and attending Clinic appointments regularly [p = 0.126] were not statistically associated with reduction in the frequency of crisis. Logistic regression analysis shows that predictors of frequent crisis were individuals who were using prophylaxis antimalarial drugs [OR = 0.12, CI = 0.05-0.33] and analgesics [OR = 0.15, C.I = 0.06-0.34]. The study reveals that majority of the participants have high frequency of crisis in a month. Drug prophylaxis rather than lifestyle factors may be more important in the prevention of vaso-occlusive crisis among sickle cell patients.

  8. Influence of food intake and eating habits on hypertension control among outpatients at a government health clinic in the Klang Valley, Malaysia.

    PubMed

    Suzana, S; Azlinda, A; Hin, S L; Khor, W H; Zahara, Z; Sa'ida, Munira J; Norliza, M

    2011-08-01

    In Malaysia, hypertension prevalence has increased from 13% in 1996 to 43% in 2006 based on the Third National Health and Morbidity Survey. Recognising the importance of hypertension control to prevent cardiovascular morbidity and mortality, a cross-sectional study was carried out to assess factors influencing blood pressure among 74 hypertensive adults (22 men, 52 women, mean age 61.1 +/- 8.8 years old) attending an outpatient clinic of a government health clinic in Klang Valley. Subjects were interviewed to obtain information on social and health, physical activity level and food intake using Diet History Questionnaire (DHQ) and Food Frequency Questionnaire (FFQ). Anthropometric measurements including weight, height, waist circumference and percentage of body fat were also conducted. The majority of the subjects (71.6%) had poor hypertension control as determined using blood pressure. Women aged 30-59 years old had a higher mean diastolic blood pressure (87.3 +/- 11.6 mmHg) than women aged 60 years old (78.5 +/- 9.5 mmHg) (p < 0.05). Most of the men (36.4%) achieved three out of six Medical Nutrition Therapy (MNT) for Hypertension Recommendations as outlined by the Malaysian Dietitians' Association. About one-third (30.8%) of the women achieved two out of six of the guidelines. High sodium intake (adjusted OR 3.501, 95% CI 1.116-10.985, p < 0.05), daily consumption of coffee (adjusted OR 0.302, 95% CI 0.093-0.983, p < 0.05) and less intake of milk (adjusted OR 3.328, 95% CI 1.055-10.493, p < 0.05) were associated with uncontrolled hypertension. Three quarters of the subjects had unsatisfactory hypertensive control and was related to food intake and eating habits including high salt diet, coffee consumption and inadequate milk intake were unsatisfactory. There is a need to implement a nutrition intervention programme based on MNT to achieve good hypertensive control among subjects.

  9. Understanding Subsurface Flow Mechanisms by Studying Recession Flow Curves

    NASA Astrophysics Data System (ADS)

    patnaik, S.; Biswal, B.; D, N.

    2013-12-01

    The recession flows offer valuable information on the subsurface systems of the drainage which cannot be observed due to technological limitations. Many analytical frameworks have been proposed in the past to analyze recession flow curves assess. Among them the most widely used one is Brutsaert-Neiber method of expressing negative time derivative of Q (discharge at the basin outlet at time t), -dQ/dt, as a function of Q itself, which eliminates the need of finding a reference time. Typically, basins across geographical regions display a power law relationship of the type: -dQ/dt = kQ^α. For a particular basin, the exponent α remains fairly constant recession events while the coefficient k varies greatly from one recession event to another, indicating the dynamic nature -dQ/dt-Q relationship. Recent observations show that subsurface storage in a basin mainly controls the dynamic parameter k. As subsurface water takes long time to fully drain, k of a recession event can also be influenced by the storage that occurred during the past rainfall events. We indirectly analyze the effect of past storage on recession flow by considering past streamflow as a proxy of past storage. A stronger relationship implies that the basin is able to store water for longer duration, and vice versa. In this study, we used streamflow data from 388 USGS basins that are relatively unaffected by human activities to find out the factors that affect the relationship between the power law correlation (R^2_PN) between past discharge and k, where the subscript N is the number of days of past streamflow observations considered for the recession event. For most of the basins R^2_PN decreases with N. We then selected 18 physical and climatological parameters for each study basin and investigated how they influence the value of R^2_PN for each N. We followed multiple linear regression method and found that R^2_PN is strongly influenced by the selected parameters (R^2 = 0.58) for N =30 days. We also

  10. The Mexican Coastal Current: A subsurface seasonal bridge that connects the tropical and subtropical Northeastern Pacific

    NASA Astrophysics Data System (ADS)

    Gómez-Valdivia, F.; Parés-Sierra, A.; Flores-Morales, A. L.

    2015-11-01

    We used a three-dimensional numerical model to analyze the seasonal variability of the coastal circulation off SW Mexico. In agreement with previous research, our model reproduced a Mexican Coastal Current (MCC) that dominates the regional poleward circulation. The modeled dynamics evidenced an energetic semiannual component that governed the subsurface seasonal variability of this poleward flow. Below the thermocline the MCC was stronger during spring and fall, when it reached subsurface seasonal-averaged velocities of ∼10 cms-1 and flowed continuously from the Gulf of Tehuantepec to the entrance of the Gulf of California. There, the subsurface MCC bifurcated in one branch that continued along the coast of mainland Mexico and a second branch that crossed the gulf and joined the California Undercurrent. Instead of the local wind, the semiannual MCC variability was induced by the transit of equatorial Kelvin waves whose upwelling (downwelling) phase propagation strengthen (weakened) the subsurface poleward circulation along the Tropical Pacific off Mexico. The MCC dynamics reported in this study accounts for the, previously reported, semiannual variability of the alongshore transport and salinity content in the southern Gulf of California. Moreover, the subsurface bridge between the MCC and the California Current System represents an external source of momentum that helps to explain the intensification of the California Undercurrent during spring and fall.

  11. Geophysical subsurface imaging and interface identification.

    SciTech Connect

    Pendley, Kevin; Bochev, Pavel Blagoveston; Day, David Minot; Robinson, Allen Conrad; Weiss, Chester Joseph

    2005-09-01

    Electromagnetic induction is a classic geophysical exploration method designed for subsurface characterization--in particular, sensing the presence of geologic heterogeneities and fluids such as groundwater and hydrocarbons. Several approaches to the computational problems associated with predicting and interpreting electromagnetic phenomena in and around the earth are addressed herein. Publications resulting from the project include [31]. To obtain accurate and physically meaningful numerical simulations of natural phenomena, computational algorithms should operate in discrete settings that reflect the structure of governing mathematical models. In section 2, the extension of algebraic multigrid methods for the time domain eddy current equations to the frequency domain problem is discussed. Software was developed and is available in Trilinos ML package. In section 3 we consider finite element approximations of De Rham's complex. We describe how to develop a family of finite element spaces that forms an exact sequence on hexahedral grids. The ensuing family of non-affine finite elements is called a van Welij complex, after the work [37] of van Welij who first proposed a general method for developing tangentially and normally continuous vector fields on hexahedral elements. The use of this complex is illustrated for the eddy current equations and a conservation law problem. Software was developed and is available in the Ptenos finite element package. The more popular methods of geophysical inversion seek solutions to an unconstrained optimization problem by imposing stabilizing constraints in the form of smoothing operators on some enormous set of model parameters (i.e. ''over-parametrize and regularize''). In contrast we investigate an alternative approach whereby sharp jumps in material properties are preserved in the solution by choosing as model parameters a modest set of variables which describe an interface between adjacent regions in physical space. While

  12. Introduction to special section on Colloid Transport in Subsurface Environments

    NASA Astrophysics Data System (ADS)

    Saiers, James E.; Ryan, Joseph N.

    2006-12-01

    The Water Resources Research special section on Colloid Transport in Subsurface Environments presents new knowledge that is critical to solving problems related to groundwater pollution by microbial pathogens and hazardous chemicals. This introduction to the special section surveys fourteen manuscripts that advance current understanding of the transport of biocolloids (e.g., bacteria, viruses, and protozoa), mineral colloids, and colloid-associated contaminants in the vadose zone and in groundwater. These papers present new techniques for elucidating mechanisms that govern colloid mobility, propose mathematical models appropriate for quantifying colloid and colloid-associated contaminant transport, and report pore-scale and column-scale observations requisite for evaluating these models. Together, the papers of this special section illuminate the complexity of the colloid transport problem and describe progress toward understanding this complexity.

  13. Wave-Based Subsurface Guide Star

    SciTech Connect

    Lehman, S K

    2011-07-26

    Astronomical or optical guide stars are either natural or artificial point sources located above the Earth's atmosphere. When imaged from ground-based telescopes, they are distorted by atmospheric effects. Knowing the guide star is a point source, the atmospheric distortions may be estimated and, deconvolved or mitigated in subsequent imagery. Extending the guide star concept to wave-based measurement systems to include acoustic, seismo-acoustic, ultrasonic, and radar, a strong artificial scatterer (either acoustic or electromagnetic) may be buried or inserted, or a pre-existing or natural sub-surface point scatterer may be identified, imaged, and used as a guide star to determine properties of the sub-surface volume. That is, a data collection is performed on the guide star and the sub-surface environment reconstructed or imaged using an optimizer assuming the guide star is a point scatterer. The optimization parameters are the transceiver height and bulk sub-surface background refractive index. Once identified, the refractive index may be used in subsequent reconstructions of sub-surface measurements. The wave-base guide star description presented in this document is for a multimonostatic ground penetrating radar (GPR) but is applicable to acoustic, seismo-acoustic, and ultrasonic measurement systems operating in multimonostatic, multistatic, multibistatic, etc., modes.

  14. DWH MC 252: Subsurface Oil Transport

    NASA Astrophysics Data System (ADS)

    Beegle-Krause, C. J.; Boyer, T.; Murray, D.

    2010-12-01

    Before reaching the ocean surface, the oil and gas released from the DWH MC 252 blowout at 1500 m moves as a buoyant plume until the trapping depth and plume transition point are reached (Zheng et al 2002). At the transition point, the oil droplets and bubbles move independently of each other, and rise at a rate related to their diameter. The oil density, droplet size distribution and currents primarily determine the distribution of the oil between: Large droplets that rise quickly and create a surface expression of the oil. Moderate size droplets that rise over the course of days, and so spread out quite differently than the surface oil, and commonly do not reach the surface in large enough quantities to create a surface sheen. These droplets separate in the currents, particularly in the strong current shear in upper 500 m currents. Very tiny droplets that rise very slowly, over the course or weeks to months, and may be removed by dissolution, biodegradation or marine snow before ever reaching the surface. Modeling and observations (Joint Analysis Group, 2010) confirm the presence of a deep layer of oil and gas between approximately 1100 and 1300 m over the release location and spreading out along the isopycnal surfaces. Later in the event, a small oxygen depression was a proxy for where oil and gas had been. The DWH MC252 well is located at intermediate depth in the Gulf of Mexico (GoM). The water mass is Antarctic Intermediate Water, which enters and exits the GoM through the Yucatan Straits. Surface influences, such as Loop Current Frontal Eddies (e.g. Berger et al 2000) can reach down to these depths, and alter the flow within De Soto Canyon. The water mass containing the deep layer of oil droplets changes depth within the GoM, but does not reach above a depth of about 900 m. There are no physical processes that could cause this deep layer of oil to reach the continental shelf or the Florida Straits. Observed and historical hydrographic data, observations

  15. Modeling subsurface contaminant reactions and transport at the watershed scale

    SciTech Connect

    Gwo, J.P.; Jardine, P.M.; D`Azevedo, E.F.; Wilson, G.V.

    1997-12-01

    The objectives of this research are: (1) to numerically examine the multiscale effects of physical and chemical mass transfer processes on watershed scale, variably saturated subsurface contaminant transport, and (2) to conduct numerical simulations on watershed scale reactive solute transport and evaluate their implications to uncertainty characterization and cost benefit analysis. Concurrent physical and chemical nonequilibrium caused by inter aggregate gradients of pressure head and solute concentration and intra-aggregate geochemical and microbiological processes, respectively, may arise at various scales and flowpaths. To this date, experimental investigations of these complex processes at watershed scale remain a challenge and numerical studies are often needed for guidance of water resources management and decision making. This research integrates the knowledge bases developed during previous experimental and numerical investigations at a proposed waste disposal site at the Oak Ridge National Laboratory to study the concurrent effects of physical and chemical nonequilibrium. Comparison of numerical results with field data indicates that: (1) multiregion, preferential flow and solute transport exist under partially saturated condition and can be confirmed theoretically, and that (2) mass transfer between pore regions is an important process influencing contaminant movement in the subsurface. Simulations of watershed scale, multi species reactive solute transport suggest that dominance of geochemistry and hydrodynamics may occur simultaneously at different locales and influence the movement of one species relative to another. Execution times on the simulations of the reactive solute transport model also indicate that the model is ready to assist the selection of important parameters for site characterization.

  16. The fiscal impact of informal caregiving to home care recipients in Canada: how the intensity of care influences costs and benefits to government.

    PubMed

    Jacobs, Josephine C; Lilly, Meredith B; Ng, Carita; Coyte, Peter C

    2013-03-01

    The objective of this study was to estimate the annual costs and consequences of unpaid caregiving by Canadians from a government perspective. We estimated these costs both at the individual and population levels for caregivers aged 45 and older. We conducted a cost-benefit analysis where we considered the costs of unpaid caregiving to be potential losses in income tax revenues and changes in social assistance payments and the potential benefit of reduced paid care expenditures. Our costing methods were based on multivariate analyses using the 2007 General Social Survey, a cross-sectional survey of 23,404 individuals. We determined the differential probability of employment, wages, and hours worked by caregivers of varying intensity versus non-caregivers. We also used multivariate analysis to determine how receiving different intensities of unpaid care impacted both the probability of receiving paid care and the weekly hours of paid care received. At the lowest intensities of caregiving, there was a net benefit to government from caregiving, at both the individual and population levels. At the population level, the net benefit to government was estimated to be $4.4 billion for caregivers providing less than five hours of weekly care. At the highest intensity of caregiving, there was a net cost to government of $641 million. Our overall findings were robust to a number of changes applied in our sensitivity analysis. We found that the factor with the greatest impact on cost was the probability of labour force participation. As the biggest cost driver appears to be the higher likelihood of intense caregivers dropping out of the labour force, government policies that enable intense caregivers to balance caregiving with employment may help to mitigate these losses.

  17. Microbial activities in deep subsurface environments

    SciTech Connect

    Phelps, T.J.; Raione, E.G.; White, D.C. |; Fliermans, C.B.

    1988-12-31

    Activities of microorganisms residing in terrestrial deep subsurface sediments were examined in forty-six sediment samples from three aseptically sampled boreholes. Radiolabeled time course experiments assessing in situ microbial activities were initiated within 30 minutes of core recovery. [{sup 14}C-1-] Acetate incorporation into lipids. [methyl-{sup 3}H-]thymidine incorporation into DNA, [{sup 14}C-2-]acetate and [{sup 14}C-U-]glucose mineralization in addition to microbial enrichment and enumeration studies were examined in surface and subsurface sediments. Surface soils contained the greatest biomass and activities followed by the shallow aquifer zones. Water saturated subsurface sediments exhibited three to four orders of magnitude greater activity and culturable microorganisms than the dense clay zones. Regardless of depth, sediments which contained more than 20% clays exhibited the lowest activities and culturable microorganisms.

  18. Autonomous microexplosives subsurface tracing system final report.

    SciTech Connect

    Engler, Bruce Phillip; Nogan, John; Melof, Brian Matthew; Uhl, James Eugene; Dulleck, George R., Jr.; Ingram, Brian V.; Grubelich, Mark Charles; Rivas, Raul R.; Cooper, Paul W.; Warpinski, Norman Raymond; Kravitz, Stanley H.

    2004-04-01

    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 of 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.

  19. Urban heat island in the subsurface

    NASA Astrophysics Data System (ADS)

    Ferguson, Grant; Woodbury, Allan D.

    2007-12-01

    The urban heat island effect has received significant attention in recent years due to the possible effect on long-term meteorological records. Recent studies of this phenomenon have suggested that this may not be important to estimates of regional climate change once data are properly corrected. However, surface air temperatures within urban environments have significant variation, making correction difficult. In the current study, we examine subsurface temperatures in an urban environment and the surrounding rural area to help characterize the nature of this variability. The results of our study indicate that subsurface temperatures are linked to land-use and supports previous work indicating that the urban heat island effect has significant and complex spatial variability. In most situations, the relationship between subsurface and surface processes cannot be easily determined, indicating that previous studies that relying on such a linkage may require further examination.

  20. Complete Subsurface Elemental Composition Measurements With PING

    NASA Technical Reports Server (NTRS)

    Parsons, A. M.

    2012-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument will measure the complete bulk elemental composition of the subsurface of Mars as well as any other solid planetary body. PING can thus be a highly effective tool for both detailed local geochemistry science investigations and precision measurements of Mars subsurface reSOurces in preparation for future human exploration. As such, PING is thus fully capable of meeting a majority of both ncar and far term elements in Challenge #1 presented for this conference. Measuring the ncar subsurface composition of Mars will enable many of the MEPAG science goals and will be key to filling an important Strategic Knowledge Gap with regard to In situ Resources Utilization (ISRU) needs for human exploration. [1, 2] PING will thus fill an important niche in the Mars Exploration Program.

  1. Anthropogenic effects on subsurface temperature in Bangkok

    NASA Astrophysics Data System (ADS)

    Taniguchi, M.

    2006-09-01

    Subsurface temperatures in Bangkok, where population and density increase rapidly, were analyzed to evaluate the effects of surface warming due to urbanization. The magnitude of surface warming evaluated from subsurface temperature in Bangkok was 1.7°C which agreed with meteorological data during the last 50 years. The depth apart from steady thermal gradient, which shows an indicator of the magnitude of surface warming due to additional heat from urbanization, was deeper at the center of the city than in the suburb areas of Bangkok. In order to separate surface warming effects into global warming effect and urbanization effect, analyses of subsurface temperature have been done depending on the distance from the city center. The results show that the expansion of urbanization in Bangkok reaches up to 80 km from the city center.

  2. Subsurface Contaminants Focus Area annual report 1997

    SciTech Connect

    1997-12-31

    In support of its vision for technological excellence, the Subsurface Contaminants Focus Area (SCFA) has identified three strategic goals. The three goals of the SCFA are: Contain and/or stabilize contamination sources that pose an imminent threat to surface and ground waters; Delineate DNAPL contamination in the subsurface and remediate DNAPL-contaminated soils and ground water; and Remove a full range of metal and radionuclide contamination in soils and ground water. To meet the challenges of remediating subsurface contaminants in soils and ground water, SCFA funded more than 40 technologies in fiscal year 1997. These technologies are grouped according to the following product lines: Dense Nonaqueous-Phase Liquids; Metals and Radionuclides; Source Term Containment; and Source Term Remediation. This report briefly describes the SCFA 1997 technologies and showcases a few key technologies in each product line.

  3. MSTS - Multiphase Subsurface Transport Simulator theory manual

    SciTech Connect

    White, M.D.; Nichols, W.E.

    1993-05-01

    The US Department of Energy, through the Yucca Mountain Site Characterization Project Office, has designated the Yucca Mountain site in Nevada for detailed study as the candidate US geologic repository for spent nuclear fuel and high-level radioactive waste. Site characterization will determine the suitability of the Yucca Mountain site for the potential waste repository. If the site is determined suitable, subsequent studies and characterization will be conducted to obtain authorization from the Nuclear Regulatory Commission to construct the potential waste repository. A principal component of the characterization and licensing processes involves numerically predicting the thermal and hydrologic response of the subsurface environment of the Yucca Mountain site to the potential repository over a 10,000-year period. The thermal and hydrologic response of the subsurface environment to the repository is anticipated to include complex processes of countercurrent vapor and liquid migration, multiple-phase heat transfer, multiple-phase transport, and geochemical reactions. Numerical simulators based on mathematical descriptions of these subsurface phenomena are required to make numerical predictions of the thermal and hydrologic response of the Yucca Mountain subsurface environment The engineering simulator called the Multiphase Subsurface Transport Simulator (MSTS) was developed at the request of the Yucca Mountain Site Characterization Project Office to produce numerical predictions of subsurface flow and transport phenomena at the potential Yucca Mountain site. This document delineates the design architecture and describes the specific computational algorithms that compose MSTS. Details for using MSTS and sample problems are given in the {open_quotes}User`s Guide and Reference{close_quotes} companion document.

  4. Improving the biodegradative capacity of subsurface bacteria

    SciTech Connect

    Romine, M.F.; Brockman, F.J.

    1993-04-01

    The continual release of large volumes of synthetic materials into the environment by agricultural and industrial sources over the last few decades has resulted in pollution of the subsurface environment. Cleanup has been difficult because of the relative inaccessibility of the contaminants caused by their wide dispersal in the deep subsurface, often at low concentrations and in large volumes. As a possible solution for these problems, interest in the introduction of biodegradative bacteria for in situ remediation of these sites has increased greatly in recent years (Timmis et al. 1988). Selection of biodegradative microbes to apply in such cleanup is limited to those strains that can survive among the native bacterial and predator community members at the particular pH, temperature, and moisture status of the site (Alexander, 1984). The use of microorganisms isolated from subsurface environments would be advantageous because the organisms are already adapted to the subsurface conditions. The options are further narrowed to strains that are able to degrade the contaminant rapidly, even in the presence of highly recalcitrant anthropogenic waste mixtures, and in conditions that do not require addition of further toxic compounds for the expression of the biodegradative capacity (Sayler et al. 1990). These obstacles can be overcome by placing the genes of well-characterized biodegradative enzymes under the control of promoters that can be regulated by inexpensive and nontoxic external factors and then moving the new genetic constructs into diverse groups of subsurface microbes. ne objective of this research is to test this hypothesis by comparing expression of two different toluene biodegradative enzymatic pathways from two different regulatable promoters in a variety of subsurface isolates.

  5. Exploring how different modes of governance act across health system levels to influence primary healthcare facility managers' use of information in decision-making: experience from Cape Town, South Africa.

    PubMed

    Scott, Vera; Gilson, Lucy

    2017-09-15

    Governance, which includes decision-making at all levels of the health system, and information have been identified as key, interacting levers of health system strengthening. However there is an extensive literature detailing the challenges of supporting health managers to use formal information from health information systems (HISs) in their decision-making. While health information needs differ across levels of the health system there has been surprisingly little empirical work considering what information is actually used by primary healthcare facility managers in managing, and making decisions about, service delivery. This paper, therefore, specifically examines experience from Cape Town, South Africa, asking the question: How is primary healthcare facility managers' use of information for decision-making influenced by governance across levels of the health system? The research is novel in that it both explores what information these facility managers actually use in decision-making, and considers how wider governance processes influence this information use. An academic researcher and four facility managers worked as co-researchers in a multi-case study in which three areas of management were served as the cases. There were iterative cycles of data collection and collaborative analysis with individual and peer reflective learning over a period of three years. Central governance shaped what information and knowledge was valued - and, therefore, generated and used at lower system levels. The central level valued formal health information generated in the district-based HIS which therefore attracted management attention across the levels of the health system in terms of design, funding and implementation. This information was useful in the top-down practices of planning and management of the public health system. However, in facilities at the frontline of service delivery, there was a strong requirement for local, disaggregated information and experiential

  6. Radar Soundings of the Subsurface of Mars

    NASA Technical Reports Server (NTRS)

    Picardi, Giovanni; Plaut, Jeffrey J.; Biccari, Daniela; Bombaci, Ornella; Calabrese, Diego; Cartacci, Marco; Cicchetti, Andrea; Clifford, Stephen M.; Edenhofer, Peter; Farrell, William M.; hide

    2005-01-01

    The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.

  7. Apparatus for passive removal of subsurface contaminants

    DOEpatents

    Pemberton, B.E.; May, C.P.; Rossabi, J.

    1997-06-24

    An apparatus is provided which passively removes contaminated gases from a subsurface. The apparatus includes a riser pipe extending into a subsurface which has an exterior end in fluid communication with a valve. When well pressure is greater than atmospheric pressure, the valve opens to release contaminants into the atmosphere, and when well pressure is less than atmospheric pressure, the valve closes to prevent flow of air into the well. The valve assembly of the invention comprises a lightweight ball which is lifted from its valve seat with a slight pressure drop between the well and the atmosphere. 7 figs.

  8. Apparatus for passive removal of subsurface contaminants

    DOEpatents

    Pemberton, Bradley E.; May, Christopher P.; Rossabi, Joseph

    1997-01-01

    An apparatus is provided which passively removes contaminated gases from a subsurface. The apparatus includes a riser pipe extending into a subsurface which has an exterior end in fluid communication with a valve. When well pressure is greater than atmospheric pressure, the valve opens to release contaminants into the atmosphere, and when well pressure is less than atmospheric pressure, the valve closes to prevent flow of air into the well. The valve assembly of the invention comprises a lightweight ball which is lifted from its valve seat with a slight pressure drop between the well and the atmosphere.

  9. Radar Soundings of the Subsurface of Mars

    NASA Technical Reports Server (NTRS)

    Picardi, Giovanni; Plaut, Jeffrey J.; Biccari, Daniela; Bombaci, Ornella; Calabrese, Diego; Cartacci, Marco; Cicchetti, Andrea; Clifford, Stephen M.; Edenhofer, Peter; Farrell, William M.; Federico, Costanzo; Frigeri, Alessandro; Gurnett, Donald A.; Hagfors, Tor; Heggy, Essam; Herique, Alain; Huff, Richard L.; Ivanov, Anton B.; Johnson, William T. K.; Jordan, Rolando L.; Kirchner, Donald L.; Kofman, Wlodek; Leuschen, Carlton J.; Nielsen, Erling; Orosei, Roberto

    2005-01-01

    The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.

  10. Subsurface Microbes Expanding the Tree of Life

    ScienceCinema

    Banfield, Jillian

    2016-07-12

    Jillian Banfield, Ph.D., UC Berkeley Professor and Berkeley Lab Earth Sciences Division staff scientist and long-time user of the DOE Joint Genome Institute’s resources shares her perspective on how the DOE JGI helps advance her research addressing knowledge gaps related to the roles of subsurface microbial communities in biogeochemical cycling. The video was filmed near the town of Rifle, Colorado at the primary field site for Phase I of the Subsurface Systems Scientific Focus Area 2.0 sponsored by the DOE Office of Biological and Environmental Research.

  11. Subsurface Microbes Expanding the Tree of Life

    SciTech Connect

    Banfield, Jillian

    2015-05-11

    Jillian Banfield, Ph.D., UC Berkeley Professor and Berkeley Lab Earth Sciences Division staff scientist and long-time user of the DOE Joint Genome Institute’s resources shares her perspective on how the DOE JGI helps advance her research addressing knowledge gaps related to the roles of subsurface microbial communities in biogeochemical cycling. The video was filmed near the town of Rifle, Colorado at the primary field site for Phase I of the Subsurface Systems Scientific Focus Area 2.0 sponsored by the DOE Office of Biological and Environmental Research.

  12. Heating systems for heating subsurface formations

    DOEpatents

    Nguyen, Scott Vinh [Houston, TX; Vinegar, Harold J [Bellaire, TX

    2011-04-26

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  13. Induction heaters used to heat subsurface formations

    DOEpatents

    Nguyen, Scott Vinh [Houston, TX; Bass, Ronald M [Houston, TX

    2012-04-24

    A heating system for a subsurface formation includes an elongated electrical conductor located in the subsurface formation. The electrical conductor extends between at least a first electrical contact and a second electrical contact. A ferromagnetic conductor at least partially surrounds and at least partially extends lengthwise around the electrical conductor. The electrical conductor, when energized with time-varying electrical current, induces sufficient electrical current flow in the ferromagnetic conductor such that the ferromagnetic conductor resistively heats to a temperature of at least about 300.degree. C.

  14. Survival and phospholipid fatty acid profiles of surface and subsurface bacteria in natural sediment microcosms

    SciTech Connect

    Kieft, T.L.; Wilch, E.; O`Connor, K.

    1997-04-01

    Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P.fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles. 40 refs., 7 figs.

  15. Subsurface clade of Geobacteraceae that predominates in a diversity of Fe(III)-reducing subsurface environments

    USGS Publications Warehouse

    Holmes, Dawn E.; O'Neil, Regina A.; Vrionis, Helen A.; N'Guessan, Lucie A.; Ortiz-Bernad, Irene; Larrahondo, Maria J.; Adams, Lorrie A.; Ward, Joy A.; Nicoll , Julie S.; Nevin, Kelly P.; Chavan, Milind A.; Johnson, Jessica P.; Long, Philip E.; Lovely, Derek R.

    2007-01-01

    There are distinct differences in the physiology of Geobacter species available in pure culture. Therefore, to understand the ecology of Geobacter species in subsurface environments, it is important to know which species predominate. Clone libraries were assembled with 16S rRNA genes and transcripts amplified from three subsurface environments in which Geobacter species are known to be important members of the microbial community: (1) a uranium-contaminated aquifer located in Rifle, CO, USA undergoing in situ bioremediation; (2) an acetate-impacted aquifer that serves as an analog for the long-term acetate amendments proposed for in situ uranium bioremediation and (3) a petroleum-contaminated aquifer in which Geobacter species play a role in the oxidation of aromatic hydrocarbons coupled with the reduction of Fe(III). The majority of Geobacteraceae 16S rRNA sequences found in these environments clustered in a phylogenetically coherent subsurface clade, which also contains a number of Geobacter species isolated from subsurface environments. Concatamers constructed with 43 Geobacter genes amplified from these sites also clustered within this subsurface clade. 16S rRNA transcript and gene sequences in the sediments and groundwater at the Rifle site were highly similar, suggesting that sampling groundwater via monitoring wells can recover the most active Geobacter species. These results suggest that further study of Geobacter species in the subsurface clade is necessary to accurately model the behavior of Geobacter species during subsurface bioremediation of metal and organic contaminants.

  16. Subsurface clade of Geobacteraceae that predominates in a diversity of Fe(III)-reducing subsurface environments

    SciTech Connect

    Holmes, Dawn; O'Neil, Regina; Vrionis, Helen A.; N'guessan, Lucie A.; Ortiz-Bernad, Irene; Larrahondo, Maria J.; Adams, Lorrie A.; Ward, Joy A.; Nicoll, Julie S.; Nevin, Kelly P.; Chavan, Milind A.; Johnson, Jessica P.; Long, Philip E.; Lovely, Derek R.

    2007-12-01

    There are distinct differences in the physiology of Geobacter species available in pure culture. Therefore, to understand the ecology of Geobacter species in subsurface environments, it is important to know which species predominate. Clone libraries were assembled with 16S rRNA genes and transcripts amplified from three subsurface environments in which Geobacter species are known to be important members of the microbial community: (1) a uranium-contaminated aquifer located in Rifle, CO, USA undergoing in situ bioremediation; (2) an acetate-impacted aquifer that serves as an analog for the long-term acetate amendments proposed for in situ uranium bioremediation and (3) a petroleum-contaminated aquifer in which Geobacter species play a role in the oxidation of aromatic hydrocarbons coupled with the reduction of Fe(III). The majority of Geobacteraceae 16S rRNA sequences found in these environments clustered in a phylogenetically coherent subsurface clade, which also contains a number of Geobacter species isolated from subsurface environments. Concatamers constructed with 43 Geobacter genes amplified from these sites also clustered within this subsurface clade. 16S rRNA transcript and gene sequences in the sediments and groundwater at the Rifle site were highly similar, suggesting that sampling groundwater via monitoring wells can recover the most active Geobacter species. These results suggest that further study of Geobacter species in the subsurface clade is necessary to accurately model the behavior of Geobacter species during subsurface bioremediation of metal and organic contaminants

  17. Association between mean and interannual equatorial Indian Ocean subsurface temperature bias in a coupled model

    NASA Astrophysics Data System (ADS)

    Srinivas, G.; Chowdary, Jasti S.; Gnanaseelan, C.; Prasad, K. V. S. R.; Karmakar, Ananya; Parekh, Anant

    2017-05-01

    In the present study the association between mean and interannual subsurface temperature bias over the equatorial Indian Ocean (EIO) is investigated during boreal summer (June through September; JJAS) in the National Centers for Environmental Prediction (NCEP) Climate Forecast System (CFSv2) hindcast. Anomalously high subsurface warm bias (greater than 3 °C) over the eastern EIO (EEIO) region is noted in CFSv2 during summer, which is higher compared to other parts of the tropical Indian Ocean. Prominent eastward current bias in the upper 100 m over the EIO region induced by anomalous westerly winds is primarily responsible for subsurface temperature bias. The eastward currents transport warm water to the EEIO and is pushed down to subsurface due to downwelling. Thus biases in both horizontal and vertical currents over the EIO region support subsurface warm bias. The evolution of systematic subsurface warm bias in the model shows strong interannual variability. These maximum subsurface warming episodes over the EEIO are mainly associated with La Niña like forcing. Strong convergence of low level winds over the EEIO and Maritime continent enhanced the westerly wind bias over the EIO during maximum warming years. This low level convergence of wind is induced by the bias in the gradient in the mean sea level pressure with positive bias over western EIO and negative bias over EEIO and parts of western Pacific. Consequently, changes in the atmospheric circulation associated with La Niña like conditions affected the ocean dynamics by modulating the current bias thereby enhancing the subsurface warm bias over the EEIO. It is identified that EEIO subsurface warming is stronger when La Niña co-occurred with negative Indian Ocean Dipole events as compared to La Niña only years in the model. Ocean general circulation model (OGCM) experiments forced with CFSv2 winds clearly support our hypothesis that ocean dynamics influenced by westerly winds bias is primarily

  18. Enzymatic activity in the surface microlayer and subsurface water in the harbour channel

    NASA Astrophysics Data System (ADS)

    Perliński, Piotr; Mudryk, Zbigniew J.; Antonowicz, Józef

    2017-09-01

    Hydrolytic activity of eight extracellular enzymes was determined spectrofluorimetric method in the surface microlayer and subsurface water in the harbour channel in Ustka. The ranking order of the potential enzyme activity rates in the studied water layers was as follows: lipase > phosphatase > aminopeptidase > β-glucosidase > α-glucosidase > xylanase > cellulase > chitinase. The level of activity of all studied hydrolases was higher in the surface microlayer than subsurface water. No clear gradients in the level of enzymatic activity were determined along the horizontal profile of the studied channel. Activity of extracellular enzymes was strongly influenced by the season.

  19. Lifetime prediction for the subsurface crack propagation using three-dimensional dynamic FEA model

    NASA Astrophysics Data System (ADS)

    Yin, Yuan; Chen, Yun-Xia; Liu, Le

    2017-03-01

    The subsurface crack propagation is one of the major interests for gear system research. The subsurface crack propagation lifetime is the number of cycles remaining for a spall to appear, which can be obtained through either stress intensity factor or accumulated plastic strain analysis. In this paper, the heavy loads are applied to the gear system. When choosing stress intensity factor, the high compressive stress suppresses Mode I stress intensities and severely reduces Mode II stress intensities in the heavily loaded lubricated contacts. Such that, the accumulated plastic strain is selected to calculate the subsurface crack propagation lifetime from the three-dimensional FEA model through ANSYS Workbench transient analysis. The three-dimensional gear FEA dynamic model with the subsurface crack is built through dividing the gears into several small elements. The calculation of the total cycles of the elements is proposed based on the time-varying accumulated plastic strain, which then will be used to calculate the subsurface crack propagation lifetime. During this process, the demonstration from a subsurface crack to a spall can be uncovered. In addition, different sizes of the elements around the subsurface crack are compared in this paper. The influences of the frictional coefficient and external torque on the crack propagation lifetime are also discussed. The results show that the lifetime of crack propagation decreases significantly when the external load T increasing from 100 N m to 150 N m. Given from the distributions of the accumulated plastic strain, the lifetime shares no significant difference when the frictional coefficient f ranging in 0.04-0.06.

  20. Progression of methanogenic degradation of crude oil in the subsurface

    USGS Publications Warehouse

    Bekins, B.A.; Hostettler, F.D.; Herkelrath, W.N.; Delin, G.N.; Warren, E.; Essaid, H.I.

    2005-01-01

    Our results show that subsurface crude-oil degradation rates at a long-term research site were strongly influenced by small-scale variations in hydrologic conditions. The site is a shallow glacial outwash aquifer located near Bemidji in northern Minnesota that became contaminated when oil spilled from a broken pipeline in August 1979. In the study area, separate-phase oil forms a subsurface oil body extending from land surface to about 1 m (3.3 ft) below the 6-8-m (20-26 ft)-deep water table. Oil saturation in the sediments ranges from 10-20% in the vadose zone to 30-70% near the water table. At depths below 2 m (6.6 ft), degradation of the separate-phase crude oil occurs under methanogenic conditions. The sequence of methanogenic alkane degradation depletes the longer chain n-alkanes before the shorter chain n-alkanes, which is opposite to the better known aerobic sequence. The rates of degradation vary significantly with location in the subsurface. Oil-coated soils within 1.5 m (5 ft) of land surface have experienced little degradation where soil water saturation is less than 20%. Oil located 2-8 m (6.6-26 ft) below land surface in areas of higher recharge has been substantially degraded. The best explanation for the association between recharge and enhanced degradation seems to be increased downward transport of microbial growth nutrients to the oil body. This is supported by observations of greater microbial numbers at higher elevations in the oil body and significant decreases with depth in nutrient concentrations, especially phosphorus. Our results suggest that environmental effects may cause widely diverging degradation rates in the same spill, calling into question dating methods based on degradation state. Copyright ?? 2005. The American Association of Petroleum Geologists/Division of Environmental Geosciences. All rights reserved.

  1. Modeling microorganism transport and survival in the subsurface.

    PubMed

    Bradford, Scott A; Wang, Yusong; Kim, Hyunjung; Torkzaban, Saeed; Šimůnek, Jiri

    2014-03-01

    An understanding of microbial transport and survival in the subsurface is needed for public health, environmental applications, and industrial processes. Much research has therefore been directed to quantify mechanisms influencing microbial fate, and the results demonstrate a complex coupling among many physical, chemical, and biological factors. Mathematical models can be used to help understand and predict the complexities of microbial transport and survival in the subsurface under given assumptions and conditions. This review highlights existing model formulations that can be used for this purpose. In particular, we discuss models based on the advection-dispersion equation, with terms for kinetic retention to solid-water and/or air-water interfaces; blocking and ripening; release that is dependent on the resident time, diffusion, and transients in solution chemistry, water velocity, and water saturation; and microbial decay (first-order and Weibull) and growth (logistic and Monod) that is dependent on temperature, nutrient concentration, and/or microbial concentration. We highlight a two-region model to account for microbe migration in the vicinity of a solid phase and use it to simulate the coupled transport and survival of species under a variety of environmentally relevant scenarios. This review identifies challenges and limitations of models to describe and predict microbial transport and survival. In particular, many model parameters have to be optimized to simulate a diversity of observed transport, retention, and survival behavior at the laboratory scale. Improved theory and models are needed to predict the fate of microorganisms in natural subsurface systems that are highly dynamic and heterogeneous.

  2. Quantifying induced effects of subsurface renewable energy storage

    NASA Astrophysics Data System (ADS)

    Bauer, Sebastian; Beyer, Christof; Pfeiffer, Tilmann; Boockmeyer, Anke; Popp, Steffi; Delfs, Jens-Olaf; Wang, Bo; Li, Dedong; Dethlefsen, Frank; Dahmke, Andreas

    2015-04-01

    New methods and technologies for energy storage are required for the transition to renewable energy sources. Subsurface energy storage systems such as salt caverns or porous formations offer the possibility of hosting large amounts of energy or substance. When employing these systems, an adequate system and process understanding is required in order to assess the feasibility of the individual storage option at the respective site and to predict the complex and interacting effects induced. This understanding is the basis for assessing the potential as well as the risks connected with a sustainable usage of these storage options, especially when considering possible mutual influences. For achieving this aim, in this work synthetic scenarios for the use of the geological underground as an energy storage system are developed and parameterized. The scenarios are designed to represent typical conditions in North Germany. The types of subsurface use investigated here include gas storage and heat storage in porous formations. The scenarios are numerically simulated and interpreted with regard to risk analysis and effect forecasting. For this, the numerical simulators Eclipse and OpenGeoSys are used. The latter is enhanced to include the required coupled hydraulic, thermal, geomechanical and geochemical processes. Using the simulated and interpreted scenarios, the induced effects are quantified individually and monitoring concepts for observing these effects are derived. This presentation will detail the general investigation concept used and analyze the parameter availability for this type of model applications. Then the process implementation and numerical methods required and applied for simulating the induced effects of subsurface storage are detailed and explained. Application examples show the developed methods and quantify induced effects and storage sizes for the typical settings parameterized. This work is part of the ANGUS+ project, funded by the German Ministry

  3. Experimental determination of methane dissolution from simulated subsurface oil leakages

    NASA Astrophysics Data System (ADS)

    Sauthoff, W.; Peltzer, E. T.; Walz, P. M.; Brewer, P. G.

    2013-12-01

    Subsurface oil leakages and increased offshore drilling efforts have raised concern over the fate of hydrocarbon mixtures of oil and gas in ocean environments. Recent wellhead and pipeline failures in the Gulf of Mexico are extreme examples of this problem. Understanding the mechanism and rate of vertical transport of hydrocarbon chemical species is necessary to predict the environmental impact of subsurface leakages. In a series of controlled experiments, we carried out a deep-sea field experiment in Monterey Canyon to investigate the behavior of a gas-saturated liquid hydrocarbon mass rising from the seafloor. Aboard the R/V Rachel Carson, we used the ROV Ventana to transport a laboratory prepared volume of decane (C10H22) saturated with methane gas (CH4) to mimic a subsurface seafloor discharge. We released the oil and gas mixture into a vertically oriented open bottom glass tube followed by methane loss rate measurements both at discrete depths, and during rapid, continuous vehicle ascent from 800 to 100 m water depth to monitor changes in dissolution and bubble nucleation. Using laser Raman techniques and HD video we quantified the chemical state of the hydrocarbon fluid, including rate of methane gas dissolution. The primary methane Raman peak was readily observable within the decane C-H stretching complex. Variation in the amount of gas dissolved in the oil greatly influences oil plume density and in turn oil plume vertical rise rate. Our results show that the rise rate of the hydrocarbon mass significantly exceeds the rate at which the excess methane was lost by dissolution. This result implies that vertical transport of methane in the saturated hydrocarbon liquid phase can greatly exceed a gas bubble plume ascending the water column from a seafloor source. These results and observations may be applicable to improved understanding of the composition, distribution, and environmental fate of leaked hydrocarbon mixtures and inform remediation efforts.

  4. Characterization of imidacloprid availability in subsurface soils

    USDA-ARS?s Scientific Manuscript database

    Degradation and sorption/desorption are the most important processes affecting the leaching of pesticides through soil because they control the amount of pesticide available for transport. Once pesticides move past the surface soil layers, variations in subsurface soil physical, chemical, and biolog...

  5. Biomarker Preservation Potential of Subsurface Ecosystems

    NASA Astrophysics Data System (ADS)

    Onstott, T. C.; Harris, R. L.; Sherwood Lollar, B.; Pedersen, K. A.; Colwell, F. S.; Pfiffner, S. M.; Phelps, T. J.; Kieft, T. L.; Bakermans, C.

    2016-05-01

    If surface life emerged on Mars it may have succumbed to a Gaian bottleneck, whereas subsurface life would have continued to grow and evolve sheltered in rocks with sub-freezing saline pore water and their remains preserved in excavated rock.

  6. Irrigation strategies using subsurface drip irrigation

    USDA-ARS?s Scientific Manuscript database

    Subsurface drip irrigation (SDI) is practiced on approximately 60,000 ha in the Texas High Plains region of the USA. Adoption of SDI continues to increase in the region. This has been attributed to record drought in Texas and the US Southwest in recent years, declining irrigation well yields, and ev...

  7. 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...

  8. Is Europa's Subsurface Water Ocean Warm?

    NASA Technical Reports Server (NTRS)

    Melosh, H. J.; Ekholm, A. G.; Showman, A. P.; Lorenz, R. D.

    2002-01-01

    Europa's subsurface water ocean may be warm: that is, at the temperature of water's maximum density. This provides a natural explanation of chaos melt-through events and leads to a correct estimate of the age of its surface. Additional information is contained in the original extended abstract.

  9. Methods for forming long subsurface heaters

    DOEpatents

    Kim, Dong Sub

    2013-09-17

    A method for forming a longitudinal subsurface heater includes longitudinally welding an electrically conductive sheath of an insulated conductor heater along at least one longitudinal strip of metal. The longitudinal strip is formed into a tubular around the insulated conductor heater with the insulated conductor heater welded along the inside surface of the tubular.

  10. Lateral gene transfer in the subsurface

    SciTech Connect

    Barkay, Tamar; Sobecky, Patricia

    2007-08-27

    Lateral gene transfer (LGT) is an important adaptive mechanism among prokaryotic organisms. This mechanism is particularly important for the response of microorganisms to changing environmental conditions because it facilitates the transfer of a large number of genes and their rapid expression. Together the transferred genes promote rapid genetic and metabolic changes that may enhance survival to newly established and sometimes hostile environmental conditions. The goal of our project was to examine if and how LGT enhances microbial adaptation to toxic heavy metals in subsurface environments that had been contaminated by mixed wastes due to activities associated with the production of nuclear energy and weapons. This task has been accomplished by dividing the project to several sub-tasks. Thus, we: (1) Determined the level of resistance of subsurface bacterial isolates to several toxic metals, all identified as pollutants of concern in subsurface environments; (2) Designed, tested, and applied, a molecular approach that determined whether metal resistance genes had evolved by LGT among subsurface bacteria; and (3) Developed a DNA hybridization array for the identification of broad host range plasmids and of metal resistance plasmids. The results are briefly summarized below with references to published papers and manuscripts in preparation where details about our research can be found. Additional information may be found in copies of our published manuscripts and conference proceedings, and our yearly reports that were submitted through the RIMS system.

  11. Subsurface Remote Sensing of Kelp Forests

    NASA Astrophysics Data System (ADS)

    Allen, J. G.; Palacios, S. L.; Kudela, R. M.

    2012-12-01

    Macrocystis pyrifera, or giant kelp, provides structure and support for many marine species, and its forests rank as one of the most ecologically productive systems in the world. Traditional, in situ measurements of kelp biomass and productivity are episodic, costly, and provide limited spatial coverage across the often wide swaths of kelp ecosystems. While satellite methods have been developed to estimate kelp biomass and productivity, satellite observations are also limited, as standard practices for measuring terrestrial vegetation cannot be applied with the same confidence to marine vegetation. Here, data gathered from flights with the MASTER sensor over the Santa Barbara Channel allowed the development of two algorithms to assess the surface and subsurface areal extent of kelp in multispectral imagery. The first, a marine vegetation index (MVI), was developed from imagery to capture both surface and sub-surface vegetation pixels. The second algorithm is based on a spectral library for kelp radiance collected from field samples and modeled using the radiative transfer equations with the HydroLight software package. The endmember collection from this library was used in the Spectral Angle Mapping tool in ENVI to identify kelp at various depths. Outputs from each of these algorithms were then compared to the Normalized Difference Vegetation Index (NDVI). Analyzing spectral properties of sub-surface features will facilitate the use of satellites in measuring extent and productivity of marine ecosystems. Furthermore, these tools allow researchers to directly quantify the depth and extent of subsurface vegetation, greatly enhancing existing methods.

  12. Smouldering Subsurface Fires in the Earth System

    NASA Astrophysics Data System (ADS)

    Rein, Guillermo

    2010-05-01

    Smouldering fires, the slow, low-temperature, flameless form of combustion, are an important phenomena in the Earth system. These fires propagate slowly through organic layers of the forest ground and are responsible for 50% or more of the total biomass consumed during wildfires. Only after the 2002 study of the 1997 extreme haze event in South-East Asia, the scientific community recognised the environmental and economic threats posed by subsurface fires. This was caused by the spread of vast biomass fires in Indonesia, burning below the surface for months during the El Niño climate event. It has been calculated that these fires released between 0.81 and 2.57 Gton of carbon gases (13-40% of global emissions). Large smouldering fires are rare events at the local scale but occur regularly at a global scale. Once ignited, they are particularly difficult to extinguish despite extensive rains or fire-fighting attempts and can persist for long periods of time (months, years) spreading over very extensive areas of forest and deep into the soil. Indeed, these are the oldest continuously burning fires on Earth. Earth scientists are interested in smouldering fires because they destroy large amounts of biomass and cause greater damage to the soil ecosystem than flaming fires do. Moreover, these fires cannot be detected with current satellite remote sensing technologies causing inconsistencies between emission inventories and model predictions. Organic soils sustain smouldering fire (hummus, duff, peat and coal) which total carbon pool exceeds that of the world's forests or the atmosphere. This have important implications for climate change. Warmer temperatures at high latitudes are resulting in unprecedented permafrost thaw that is leaving large soil carbon pools exposed to fires. Because the CO2 flux from peat fires has been measured to be about 3000 times larger that the natural degradation flux, permafrost thaw is a risk for greater carbon release by fire and subsequently

  13. Complex Systems Science for Subsurface Fate and Transport Report from the August 2009 Workshop

    SciTech Connect

    2010-03-01

    The subsurface environment, which encompasses the vadose and saturated zones, is a heterogeneous, geologically complex domain. Believed to contain a large percentage of Earth's biomass in the form of microorganisms, the subsurface is a dynamic zone where important biogeochemical cycles work to sustain life. Actively linked to the atmosphere and biosphere through the hydrologic and carbon cycles, the subsurface serves as a storage location for much of Earth's fresh water. Coupled hydrological, microbiological, and geochemical processes occurring within the subsurface environment cause the local and regional natural chemical fluxes that govern water quality. These processes play a vital role in the formation of soil, economically important fossil fuels, mineral deposits, and other natural resources. Cleaning up Department of Energy (DOE) lands impacted by legacy wastes and using the subsurface for carbon sequestration or nuclear waste isolation require a firm understanding of these processes and the documented means to characterize the vertical and spatial distribution of subsurface properties directing water, nutrient, and contaminant flows. This information, along with credible, predictive models that integrate hydrological, microbiological, and geochemical knowledge over a range of scales, is needed to forecast the sustainability of subsurface water systems and to devise ways to manage and manipulate dynamic in situ processes for beneficial outcomes. Predictive models provide the context for knowledge integration. They are the primary tools for forecasting the evolving geochemistry or microbial ecology of groundwater under various scenarios and for assessing and optimizing the potential effectiveness of proposed approaches to carbon sequestration, waste isolation, or environmental remediation. An iterative approach of modeling and experimentation can reveal powerful insights into the behavior of subsurface systems. State-of-science understanding codified in models

  14. Subsurface microbial community structure correlates with uranium redox phases during in situ field manipulation in a contaminated aquifer

    SciTech Connect

    Kostka, Joel; Green, Stefan; Wu, Wei-min; Criddle, Craig; Watson, David B; Jardine, Philip M

    2009-07-01

    Long-term field manipulation experiments investigating the effects of subsurface redox conditions on the fate and transport of soluble uranium(VI) were conducted over a 3 year period at the Oak Ridge Integrated Field Research Center (OR-IFRC) in Oak Ridge, TN. In the highly contaminated source zone, introduction of ethanol to the subsurface stimulated native denitrifying, sulfate-reducing, iron-reducing and fermentative microorganisms and reduced U to below 0.03 mg/L. Subsequently, oxygen and nitrate were experimentally re-introduced into the subsurface to examine the potential for re-oxidation and re-mobilization of U(IV). Introduction of oxygen or nitrate caused changes in subsurface geochemistry and re-oxidation of U. After reoxidation, the subsurface experienced several months of starvation conditions before ethanol injection was restored to reduce the treatment zone. Subsurface microorganisms were characterized by community fingerprinting, targeted population analyses, and quantitative PCR of key functional groups in 50 samples taken during multiple phases of field manipulation. Statistical analysis confirmed the hypothesis that the microbial community would co-vary with the shifts in the subsurface geochemistry. The level of hydraulic connectivity of sampling wells to the injection well was readily tracked by microbial community analysis. We demonstrate quantitatively that specific populations, especially Desulfosporosinus, are heavily influenced by geochemical conditions and positively correlate with the immobilization of uranium. Following nitrate reoxidation, populations of Fe(II)-oxidizing, nitrate reducing organisms (Thiobacillus) showed an increase in relative abundance.

  15. Mixing of Surface and Subsurface Organic Matter During Catchment Formation at Springs

    NASA Astrophysics Data System (ADS)

    Birdwell, J. E.; Engel, A. S.

    2008-12-01

    When spring waters form or enter existing catchments, spring geochemistry and discharge can affect local surface aquatic biogeochemistry by introducing different chemical and biological species. In this study, we applied excitation-emission matrix fluorescence spectroscopy to water samples and extracted organic matter (OM) solutions from surface solids (soil, pine needles, microbial mats) to examine OM mixing in a small pool at the outlet of a sulfidic spring in a Louisiana forest. At this site, the spring water contributes hydrogen sulfide and subsurface microbes, which differ geochemically and biologically from soil pore water or meteoric sources. The original signature of the subsurface OM was obtained by isolation from spring water using a C- 18 adsorbent following filtration to remove microbes. Surface OM signatures from soil and microbial mats were obtained using traditional humic substance extraction techniques. Comparisons of fluorescence characteristics show that OM composition and concentration change significantly over < 2 m stream reach from the spring orifice. In addition to mixing of surface and subsurface OM, surface mechanisms influence the OM signatures, including photodegradation and photooxidation, as well as microbial OM turnover and processing. It is apparent from our results that the contribution of subsurface material to surface environments has great influence on the biogeochemistry near the point of emission, but that influence is rapidly mitigated as the waters equilibrate with the atmosphere and surrounding soil.

  16. Subsurface barrier verification technologies, informal report

    SciTech Connect

    Heiser, J.H.

    1994-06-01

    One of the more promising remediation options available to the DOE waste management community is subsurface barriers. Some of the uses of subsurface barriers include surrounding and/or containing buried waste, as secondary confinement of underground storage tanks, to direct or contain subsurface contaminant plumes and to restrict remediation methods, such as vacuum extraction, to a limited area. To be most effective the barriers should be continuous and depending on use, have few or no breaches. A breach may be formed through numerous pathways including: discontinuous grout application, from joints between panels and from cracking due to grout curing or wet-dry cycling. The ability to verify barrier integrity is valuable to the DOE, EPA, and commercial sector and will be required to gain full public acceptance of subsurface barriers as either primary or secondary confinement at waste sites. It is recognized that no suitable method exists for the verification of an emplaced barrier`s integrity. The large size and deep placement of subsurface barriers makes detection of leaks challenging. This becomes magnified if the permissible leakage from the site is low. Detection of small cracks (fractions of an inch) at depths of 100 feet or more has not been possible using existing surface geophysical techniques. Compounding the problem of locating flaws in a barrier is the fact that no placement technology can guarantee the completeness or integrity of the emplaced barrier. This report summarizes several commonly used or promising technologies that have been or may be applied to in-situ barrier continuity verification.

  17. Quantifying nonisothermal subsurface soil water evaporation

    NASA Astrophysics Data System (ADS)

    Deol, Pukhraj; Heitman, Josh; Amoozegar, Aziz; Ren, Tusheng; Horton, Robert

    2012-11-01

    Accurate quantification of energy and mass transfer during soil water evaporation is critical for improving understanding of the hydrologic cycle and for many environmental, agricultural, and engineering applications. Drying of soil under radiation boundary conditions results in formation of a dry surface layer (DSL), which is accompanied by a shift in the position of the latent heat sink from the surface to the subsurface. Detailed investigation of evaporative dynamics within this active near-surface zone has mostly been limited to modeling, with few measurements available to test models. Soil column studies were conducted to quantify nonisothermal subsurface evaporation profiles using a sensible heat balance (SHB) approach. Eleven-needle heat pulse probes were used to measure soil temperature and thermal property distributions at the millimeter scale in the near-surface soil. Depth-integrated SHB evaporation rates were compared with mass balance evaporation estimates under controlled laboratory conditions. The results show that the SHB method effectively measured total subsurface evaporation rates with only 0.01-0.03 mm h-1difference from mass balance estimates. The SHB approach also quantified millimeter-scale nonisothermal subsurface evaporation profiles over a drying event, which has not been previously possible. Thickness of the DSL was also examined using measured soil thermal conductivity distributions near the drying surface. Estimates of the DSL thickness were consistent with observed evaporation profile distributions from SHB. Estimated thickness of the DSL was further used to compute diffusive vapor flux. The diffusive vapor flux also closely matched both mass balance evaporation rates and subsurface evaporation rates estimated from SHB.

  18. Simulation for ground penetrating radar (GPR) study of the subsurface structure of the Moon

    NASA Astrophysics Data System (ADS)

    Fa, Wenzhe

    2013-12-01

    Ground penetrating radar (GPR) is currently within the scope of China's Chang-E 3 lunar mission, to study the shallow subsurface of the Moon. In this study, key factors that could affect a lunar GPR performance, such as frequency, range resolution, and antenna directivity, are discussed firstly. Geometrical optics and ray tracing techniques are used to model GPR echoes, considering the transmission, attenuation, reflection, geometrical spreading of radar waves, and the antenna directivity. The influence on A-scope GPR echoes and on the simulated radargrams for the Sinus Iridum region by surface and subsurface roughness, dielectric loss of the lunar regolith, radar frequency and bandwidth, and the distance between the transmit and receive antennas are discussed. Finally, potential scientific return about lunar subsurface properties from GPR echoes is also discussed. Simulation results suggest that subsurface structure from several to hundreds of meters can be studied from GPR echoes at P and VHF bands, and information about dielectric permittivity and thickness of subsurface layers can be estimated from GPR echoes in combination with regolith composition data.

  19. Sub-surface imaging of carbon nanotube-polymer composites using dynamic AFM methods.

    PubMed

    Cadena, Maria J; Misiego, Rocio; Smith, Kyle C; Avila, Alba; Pipes, Byron; Reifenberger, Ron; Raman, Arvind

    2013-04-05

    High-resolution sub-surface imaging of carbon nanotube (CNT) networks within polymer nanocomposites is demonstrated through electrical characterization techniques based on dynamic atomic force microscopy (AFM). We compare three techniques implemented in the single-pass configuration: DC-biased amplitude modulated AFM (AM-AFM), electrostatic force microscopy (EFM) and Kelvin probe force microscopy (KPFM) in terms of the physics of sub-surface image formation and experimental robustness. The methods were applied to study the dispersion of sub-surface networks of single-walled nanotubes (SWNTs) in a polyimide (PI) matrix. We conclude that among these methods, the KPFM channel, which measures the capacitance gradient (∂C/∂d) at the second harmonic of electrical excitation, is the best channel to obtain high-contrast images of the CNT network embedded in the polymer matrix, without the influence of surface conditions. Additionally, we propose an analysis of the ∂C/∂d images as a tool to characterize the dispersion and connectivity of the CNTs. Through the analysis we demonstrate that these AFM-based sub-surface methods probe sufficiently deep within the SWNT composites, to resolve clustered networks that likely play a role in conductivity percolation. This opens up the possibility of dynamic AFM-based characterization of sub-surface dispersion and connectivity in nanostructured composites, two critical parameters for nanocomposite applications in sensors and energy storage devices.

  20. Is the genetic landscape of the deep subsurface biosphere affected by viruses?

    PubMed

    Anderson, Rika E; Brazelton, William J; Baross, John A

    2011-01-01

    Viruses are powerful manipulators of microbial diversity, biogeochemistry, and evolution in the marine environment. Viruses can directly influence the genetic capabilities and the fitness of their hosts through the use of fitness factors and through horizontal gene transfer. However, the impact of viruses on microbial ecology and evolution is often overlooked in studies of the deep subsurface biosphere. Subsurface habitats connected to hydrothermal vent systems are characterized by constant fluid flux, dynamic environmental variability, and high microbial diversity. In such conditions, high adaptability would be an evolutionary asset, and the potential for frequent host-virus interactions would be high, increasing the likelihood that cellular hosts could acquire novel functions. Here, we review evidence supporting this hypothesis, including data indicating that microbial communities in subsurface hydrothermal fluids are exposed to a high rate of viral infection, as well as viral metagenomic data suggesting that the vent viral assemblage is particularly enriched in genes that facilitate horizontal gene transfer and host adaptability. Therefore, viruses are likely to play a crucial role in facilitating adaptability to the extreme conditions of these regions of the deep subsurface biosphere. We also discuss how these results might apply to other regions of the deep subsurface, where the nature of virus-host interactions would be altered, but possibly no less important, compared to more energetic hydrothermal systems.

  1. Is the Genetic Landscape of the Deep Subsurface Biosphere Affected by Viruses?

    PubMed Central

    Anderson, Rika E.; Brazelton, William J.; Baross, John A.

    2011-01-01

    Viruses are powerful manipulators of microbial diversity, biogeochemistry, and evolution in the marine environment. Viruses can directly influence the genetic capabilities and the fitness of their hosts through the use of fitness factors and through horizontal gene transfer. However, the impact of viruses on microbial ecology and evolution is often overlooked in studies of the deep subsurface biosphere. Subsurface habitats connected to hydrothermal vent systems are characterized by constant fluid flux, dynamic environmental variability, and high microbial diversity. In such conditions, high adaptability would be an evolutionary asset, and the potential for frequent host–virus interactions would be high, increasing the likelihood that cellular hosts could acquire novel functions. Here, we review evidence supporting this hypothesis, including data indicating that microbial communities in subsurface hydrothermal fluids are exposed to a high rate of viral infection, as well as viral metagenomic data suggesting that the vent viral assemblage is particularly enriched in genes that facilitate horizontal gene transfer and host adaptability. Therefore, viruses are likely to play a crucial role in facilitating adaptability to the extreme conditions of these regions of the deep subsurface biosphere. We also discuss how these results might apply to other regions of the deep subsurface, where the nature of virus–host interactions would be altered, but possibly no less important, compared to more energetic hydrothermal systems. PMID:22084639

  2. Hillslope permeability architecture controls on subsurface transit time distribution and flow paths

    NASA Astrophysics Data System (ADS)

    Ameli, A. A.; Amvrosiadi, N.; Grabs, T.; Laudon, H.; Creed, I. F.; McDonnell, J. J.; Bishop, K.

    2016-12-01

    Defining the catchment transit time distribution remains a challenge. Here, we used a new semi-analytical physically-based integrated subsurface flow and advective-dispersive particle movement model to assess the subsurface controls on subsurface water flow paths and transit time distributions. First, we tested the efficacy of the new model for simulation of the observed groundwater dynamics at the well-studied S-transect hillslope (Västrabäcken sub-catchment, Sweden). This system, like many others, is characterized by exponential decline in saturated hydraulic conductivity and porosity with soil depth. The model performed well relative to a tracer-based estimate of transit time distribution as well as observed groundwater depth-discharge relationship within 30 m of the stream. Second, we used the model to assess the effect of changes in the subsurface permeability architecture on flow pathlines and transit time distribution in a set of virtual experiments. Vertical patterns of saturated hydraulic conductivity and porosity with soil depth significantly influenced hillslope transit time distribution. Increasing infiltration rates significantly decreased mean groundwater age, but not the distribution of transit times relative to mean groundwater age. The location of hillslope hydrologic boundaries, including the groundwater divide and no-flow boundary underlying the hillslope, changed the transit time distribution less markedly. These results can guide future decisions on the degree of complexity that is warranted in a physically-based rainfall-runoff model to efficiently and explicitly estimate time invariant subsurface pathlines and transit time distribution.

  3. Aqueous complexation reactions governing the rate and extent of biogeochemical U(VI) reduction

    SciTech Connect

    Kemner, K.M.; Kelly, S.D.; Brooks, Scott C.; Dong, Wenming; Carroll, Sue; Fredrickson, James K.

    2006-06-01

    The proposed research will elucidate the principal biogeochemical reactions that govern the concentration, chemical speciation, and reactivity of the redox-sensitive contaminant uranium. The results will provide an improved understanding and predictive capability of the mechanisms that govern the biogeochemical reduction of uranium in subsurface environments.

  4. Subsurface Environment Sampler for Improved In Situ Characterization of Subsurface Microbial Communities

    NASA Astrophysics Data System (ADS)

    Barnhart, E. P.; Ruppert, L. F.; Orem, W. H.; McIntosh, J. C.; Cunningham, A. B.; Fields, M. W.; Hiebert, R.; Hyatt, R.

    2016-12-01

    There is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by the extraction and transport of fossil fuels. This threat increases the need for improved groundwater monitoring and the ability to predict the extent to which microbial activity may remediate such contamination. The characterization of subsurface microbial communities could provide an ideal biomonitoring tool for the assessment of subsurface contamination due to prokaryotes environmental ubiquity, rapidity of response to environmental perturbation and the important role they play in hydrocarbon degradation and bioremediation. New DNA sequencing technologies provide the opportunity to cost-effectively identify the vast subsurface microbial ecosystem, but use of this new technology is restricted due to issues with sampling. Prior subsurface microbiology studies have relied on core samples that are expensive to obtain hard to collect aseptically and/or ground water samples that do not reflect in situ microbial densities or activities. The development of down-well incubation of sterile sediment with a Diffusive Microbial Sampler (DMS) has emerged as an alternative method to sample subsurface microbial communities that minimizes cost and contamination issues associated with traditional methods. We have designed a Subsurface Environment Sampler with a DMS module that could enable the anaerobic transport of the in situ microbial community from the field for laboratory bioremediation studies. This sampler could provide an inexpensive and standard method for subsurface microbial sampling which would make this tool useful for Federal, State, private and local agencies interested in monitoring contamination or the effectiveness of bioremediation activities in subsurface aquifers.

  5. Spatial resolution of subsurface anthropogenic heat fluxes in cities

    NASA Astrophysics Data System (ADS)

    Benz, Susanne; Bayer, Peter; Menberg, Kathrin; Blum, Philipp

    2015-04-01

    Urban heat islands in the subsurface contain large quantities of energy in the form of elevated groundwater temperatures caused by anthropogenic heat fluxes (AHFS) into the subsurface. Hence, the objective of this study is to exemplarily quantify these AHFS and the generated thermal powers in two German cities, Karlsruhe and Cologne. A two-dimensional (2D) statistical analytical model of the vertical subsurface anthropogenic heat fluxes across the unsaturated zone was developed. The model consists of a so-called Local Monte Carlo approach that introduces a spatial representation of the following sources of AHFS: (1) elevated ground surface temperatures, (2) basements, (3) sewage systems, (4) sewage leakage, (5) subway tunnels, and (6) district heating networks. The results show that district heating networks induce the largest local AHFS with values larger than 60 W/m2 and one order of magnitude higher than the other evaluated heat sources. Only sewage pipes and basements reaching into the groundwater cause equally high heat fluxes, with maximal values of 40.37 W/m2 and 13.60 W/m2, respectively. While dominating locally, the district heating network is rather insignificant for the citywide energy budget in both urban subsurfaces. Heat from buildings (1.51 ± 1.36 PJ/a in Karlsruhe; 0.31 ± 0.14 PJ/a in Cologne) and elevated GST (0.34 ± 0.10 PJ/a in Karlsruhe; 0.42 ± 0.13 PJ/a in Cologne) are dominant contributors to the anthropogenic thermal power of the urban aquifer. In Karlsruhe, buildings are the source of 70% of the annual heat transported into the groundwater, which is mainly caused by basements reaching into the groundwater. A variance analysis confirms these findings: basement depth is the most influential factor to citywide thermal power in the studied cities with high groundwater levels. The spatial distribution of fluxes, however, is mostly influenced by the prevailing thermal gradient across the unsaturated zone. A relatively cold groundwater

  6. Subsurface imaging of two-dimensional materials at the nanoscale

    NASA Astrophysics Data System (ADS)

    Dinelli, Franco; Pingue, Pasqualantonio; Kay, Nicholas D.; Kolosov, Oleg V.

    2017-02-01

    Scanning probe microscopy (SPM) represents a powerful tool that, in the past 30 years, has allowed for the investigation of material surfaces in unprecedented ways at the nanoscale level. However, SPM has shown very little capability for depth penetration, which several nanotechnology applications require. Subsurface imaging has been achieved only in a few cases, when subsurface features influence the physical properties of the surface, such as the electronic states or the heat transfer. Ultrasonic force microscopy (UFM), an adaption of the contact mode atomic force microscopy, can dynamically measure the stiffness of the elastic contact between the probing tip and the sample surface. In particular, UFM has proven highly sensitive to the near-surface elastic field in non-homogeneous samples. In this paper, we present an investigation of two-dimensional (2D) materials, namely flakes of graphite and molybdenum disulphide placed on structured polymeric substrates. We show that UFM can non-destructively distinguish suspended and supported areas and localise defects, such as buckling or delamination of adjacent monolayers, generated by residual stress. Specifically, UFM can probe small variations in the local indentation induced by the mechanical interaction between the tip and the sample. Therefore, any change in the elastic modulus within the volume perturbed by the applied load or the flexural bending of the suspended areas can be detected and imaged. These investigation capabilities are very promising in order to study the buried interfaces of nanostructured 2D materials such as in graphene-based devices.

  7. Impact disruption and recovery of the deep subsurface biosphere.

    PubMed

    Cockell, Charles S; Voytek, Mary A; Gronstal, Aaron L; Finster, Kai; Kirshtein, Julie D; Howard, Kieren; Reitner, Joachim; Gohn, Gregory S; Sanford, Ward E; Horton, J Wright; Kallmeyer, Jens; Kelly, Laura; Powars, David S

    2012-03-01

    Although a large fraction of the world's biomass resides in the subsurface, there has been no study of the effects of catastrophic disturbance on the deep biosphere and the rate of its subsequent recovery. We carried out an investigation of the microbiology of a 1.76 km drill core obtained from the ∼35 million-year-old Chesapeake Bay impact structure, USA, with robust contamination control. Microbial enumerations displayed a logarithmic downward decline, but the different gradient, when compared to previously studied sites, and the scatter of the data are consistent with a microbiota influenced by the geological disturbances caused by the impact. Microbial abundance is low in buried crater-fill, ocean-resurge, and avalanche deposits despite the presence of redox couples for growth. Coupled with the low hydraulic conductivity, the data suggest the microbial community has not yet recovered from the impact ∼35 million years ago. Microbial enumerations, molecular analysis of microbial enrichment cultures, and geochemical analysis showed recolonization of a deep region of impact-fractured rock that was heated to above the upper temperature limit for life at the time of impact. These results show how, by fracturing subsurface rocks, impacts can extend the depth of the biosphere. This phenomenon would have provided deep refugia for life on the more heavily bombarded early Earth, and it shows that the deeply fractured regions of impact craters are promising targets to study the past and present habitability of Mars.

  8. Impact disruption and recovery of the deep subsurface biosphere

    USGS Publications Warehouse

    Cockell, Charles S.; Voytek, Mary A.; Gronstal, Aaron L.; Finster, Kai; Kirshtein, Julie D.; Howard, Kieren; Reitner, Joachim; Gohn, Gregory S.; Sanford, Ward E.; Horton, J. Wright; Kallmeyer, Jens; Kelly, Laura; Powars, David S.

    2012-01-01

    Although a large fraction of the world's biomass resides in the subsurface, there has been no study of the effects of catastrophic disturbance on the deep biosphere and the rate of its subsequent recovery. We carried out an investigation of the microbiology of a 1.76 km drill core obtained from the ~35 million-year-old Chesapeake Bay impact structure, USA, with robust contamination control. Microbial enumerations displayed a logarithmic downward decline, but the different gradient, when compared to previously studied sites, and the scatter of the data are consistent with a microbiota influenced by the geological disturbances caused by the impact. Microbial abundance is low in buried crater-fill, ocean-resurge, and avalanche deposits despite the presence of redox couples for growth. Coupled with the low hydraulic conductivity, the data suggest the microbial community has not yet recovered from the impact ~35 million years ago. Microbial enumerations, molecular analysis of microbial enrichment cultures, and geochemical analysis showed recolonization of a deep region of impact-fractured rock that was heated to above the upper temperature limit for life at the time of impact. These results show how, by fracturing subsurface rocks, impacts can extend the depth of the biosphere. This phenomenon would have provided deep refugia for life on the more heavily bombarded early Earth, and it shows that the deeply fractured regions of impact craters are promising targets to study the past and present habitability of Mars.

  9. Subsurface temperature distribution in a tropical alluvial fan

    NASA Astrophysics Data System (ADS)

    Chen, Wenfu; Chang, Minhsiang; Chen, Juier; Lu, Wanchung; Huang, Chihc; Wang, Yunshuen

    2017-04-01

    As a groundwater intensive use country, Taiwan's 1/3 water supplies are derived from groundwater. The major aquifers consist of sand and gravel formed in alluvial fans which border the fronts of central mountains. Thanks to high density of monitoring wells which provide a window to see the details of the subsurface temperature distribution and the thermal regime in an alluvial fan system. Our study area, the Choshui Alluvial Fan, is the largest groundwater basin in Taiwan and, located within an area of 2,000 km2, has a population of over 1.5 million. For this work, we investigated temperature-depth profiles using 70 groundwater monitoring wells during 2000 to 2015. Our results show that the distribution of subsurface temperature is influenced by various factors such as groundwater recharge, groundwater flow field, air temperature and land use. The groundwater recharge zone, hills to the upper fan, contains disturbed and smaller geothermal gradients. The lack of clay layers within the upper fan aquifers and fractures that developed in the hills should cause the convection and mixing of cooler recharge water to groundwater, resulting in smaller geothermal gradients. The groundwater temperatures at a depth to 300 m within the upper fan and hill were approximately only 23-24 °C while the current mean ground surface temperature is approximately 26 °C.

  10. Combined NDT methods for characterization of subsurface cracks in concrete

    NASA Astrophysics Data System (ADS)

    Kordatos, E. Z.; Strantza, M.; Soulioti, D. V.; Matikas, T. E.; Aggelis, D. G.

    2011-04-01

    One of the most frequent problems in concrete structures is corrosion of metal reinforcement. It occurs when the steel reinforcement is exposed to environmental agents. The corrosion products occupy greater volume than the steel consumed, leading to internal expansion stresses. When the stresses exceed concrete strength, eventually lead to corrosion-induced cracking beneath the surface. These cracks do not show any visual sign until they break the surface, exposing the structure to more accelerated deterioration. In order to develop a methodology for sub-surface damage characterization, a combination of non destructive testing (NDT) techniques was applied. Thermography is specialized in subsurface damage identification due to anomalies that inhomogeneities impose on the temperature field. Additionally, ultrasonic surface waves are constrained near the surface and therefore, are ideal for characterization of near-surface damage. In this study, an infrared camera scans the specimen in order to indicate the position of potential damage. For cases of small cracks, the specimens are allowed to cool and the cooling-off curve is monitored for more precise results. Consequently, ultrasonic sensors are placed on the specified part of the surface in order to make a more detailed assessment for the depth of the crack. Although there is no visual sign of damage, surface waves are influenced in terms of velocity and attenuation. The combination of the NDT techniques seems promising for real structures assessment.

  11. Subsurface imaging of two-dimensional materials at the nanoscale.

    PubMed

    Dinelli, Franco; Pingue, Pasqualantonio; Kay, Nicholas D; Kolosov, Oleg V

    2017-02-24

    Scanning probe microscopy (SPM) represents a powerful tool that, in the past 30 years, has allowed for the investigation of material surfaces in unprecedented ways at the nanoscale level. However, SPM has shown very little capability for depth penetration, which several nanotechnology applications require. Subsurface imaging has been achieved only in a few cases, when subsurface features influence the physical properties of the surface, such as the electronic states or the heat transfer. Ultrasonic force microscopy (UFM), an adaption of the contact mode atomic force microscopy, can dynamically measure the stiffness of the elastic contact between the probing tip and the sample surface. In particular, UFM has proven highly sensitive to the near-surface elastic field in non-homogeneous samples. In this paper, we present an investigation of two-dimensional (2D) materials, namely flakes of graphite and molybdenum disulphide placed on structured polymeric substrates. We show that UFM can non-destructively distinguish suspended and supported areas and localise defects, such as buckling or delamination of adjacent monolayers, generated by residual stress. Specifically, UFM can probe small variations in the local indentation induced by the mechanical interaction between the tip and the sample. Therefore, any change in the elastic modulus within the volume perturbed by the applied load or the flexural bending of the suspended areas can be detected and imaged. These investigation capabilities are very promising in order to study the buried interfaces of nanostructured 2D materials such as in graphene-based devices.

  12. A field study of colloid transport in surface and subsurface flows

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Tang, Xiang-Yu; Xian, Qing-Song; Weisbrod, Noam; Yang, Jae E.; Wang, Hong-Lan

    2016-11-01

    Colloids have been recognized to enhance the migration of strongly-sorbing contaminants. However, few field investigations have examined combined colloid transport via surface runoff and subsurface flows. In a headwater catchment of the upper Yangtze River, a 6 m (L) by 4 m (W) sloping (6°) farmland plot was built by cement walls to form no-flow side boundaries. The plot was monitored in the summer of 2014 for the release and transport of natural colloids via surface runoff and subsurface flows (i.e., the interflow from the soil-mudrock interface and fracture flow from the mudrock-sandstone interface) in response to rain events. The water sources of the subsurface flows were apportioned to individual rain events using a two end-member model (i.e., mobile pre-event soil water extracted by a suction-cup sampler vs. rainwater (event water)) based on δ18O measurements. For rain events with high preceding soil moisture, mobile pre-event soil water was the main contributor (generally >60%) to the fracture flow. The colloid concentration in the surface runoff was 1-2 orders of magnitude higher than that in the subsurface flows. The lowest colloid concentration was found in the subsurface interflow, which was probably the result of pore-scale colloid straining mechanisms. The rainfall intensity and its temporal variation govern the dynamics of the colloid concentrations in both surface runoff and subsurface flows. The duration of the antecedent dry period affected not only the relative contributions of the rainwater and the mobile pre-event soil water to the subsurface flows but also the peak colloid concentration, particularly in the fracture flow. The <10 μm fine colloid size fraction accounted for more than 80% of the total suspended particles in the surface runoff, while the colloid size distributions of both the interflow and the fracture flow shifted towards larger diameters. These results highlight the need to avoid the application of strongly

  13. Final technical report for project titled Quantitative Characterization of Cell Aggregation/Adhesion as Predictor for Distribution and Transport of Microorganisms in Subsurface Environment

    SciTech Connect

    Gu, April Z.; Wan, Kai-tak

    2014-09-02

    This project aims to explore and develop enabling methodology and techniques for nano-scale characterization of microbe cell surface contact mechanics, interactions and adhesion quantities that allow for identification and quantification of indicative properties related to microorganism migration and transport behavior in porous media and in subsurface environments. Microbe transport has wide impact and therefore is of great interest in various environmental applications such as in situ or enhanced subsurface bioremediation,filtration processes for water and wastewater treatments and protection of drinking water supplies. Although great progress has been made towards understanding the identities and activities of these microorganisms in the subsurface, to date, little is known of the mechanisms that govern the mobility and transport of microorganisms in DOE’s contaminated sites, making the outcomes of in situ natural attenuation or contaminant stability enhancement unpredictable. Conventionally, movement of microorganisms was believed to follows the rules governing solute (particle) transport. However, recent studies revealed that cell surface properties, especially those pertaining to cell attachment/adhesion and aggregation behavior, can cause the microbe behavior to deviate from non-viable particles and hence greatly influence the mobility and distribution of microorganisms in porous media.This complexity highlights the need to obtain detailed information of cell-cell and cell-surface interactions in order to improve and refine the conceptual and quantitative model development for fate and transport of microorganisms and contaminant in subsurface. Traditional cell surface characterization methods are not sufficient to fully predict the deposition rates and transport behaviors of microorganism observed. A breakthrough of methodology that would allow for quantitative and molecular-level description of intrinsic cell surface properties indicative for cell

  14. Microbial communities in subsurface environments: Diversity, origin, and evolution. Project technical progress report, September 1, 1993--August 31, 1996

    SciTech Connect

    Nierzwicki-Bauer, S.A.

    1994-05-02

    This report summarizes the progress made from 9-1-93 to 5-1-94 on this DOE grant. As participants in the subsurface science program, the authors are assessing the influence of environmental conditions on the distribution and evolution of subsurface microorganisms employing molecular techniques. The approach utilizes 16S rRNA targeted oligonucleotide probes, polymerase chain reaction (PCR) amplification of gene sequences, and sequencing techniques. Continued progress towards identifying target sequences for selected microbial types and groups is being made by analysis of rRNA sequence data for subsurface microorganisms and other microorganisms in the rRNA databases. Hybridization probes for these target sequences are being produced and used to classify isolated strains of subsurface microbes into focus clades useful for testing origins hypotheses.

  15. English obesity policies: To govern and not to govern.

    PubMed

    Vallgårda, Signild

    2015-06-01

    Problem definitions constitute a crucial part of the policy process. In 2008 the Labour Government presented a plan to reduce the obesity prevalence in England. Only three years later the Conservative-Liberal Government introduced a plan on the same topic, which it presented as new and innovative. The aim of this study is to analyse the respective governments' problematisations of obesity and to identify similarities and differences. Despite the different hues of the two governments, the programmes are surprisingly similar. They seek to simultaneously govern and not to govern. They adhere to liberal ideals of individual choice and they also suggest initiatives that will lead people to choose certain behaviours. Both governments encourage the food and drink industry to support their policies voluntarily, rather than obliging them to do so, although Labour is somewhat more inclined to use statutory measures. The Conservative-Liberal plan does not represent many new ideas. The plans are characterised by the paradox that they convey both ideas and ideals about freedom of choice as well as about state interventions to influence people's choices, which could be seen as incompatible, but as the study shows in practice they are not.

  16. Governance of Governance in Higher Education: Practices and Lessons Drawn from the Portuguese Case

    ERIC Educational Resources Information Center

    Magalhaes, Antonio; Veiga, Amelia; Amaral, Alberto; Sousa, Sofia; Ribeiro, Filipa

    2013-01-01

    The implementation of the governance reform of Portuguese higher education has been developed under the influence of "new public management" resulting in the loss of collegial governance. Additionally, the need for meta-governance of the higher education system and institutions to monitor institutional performance against policy…

  17. Governance of Governance in Higher Education: Practices and Lessons Drawn from the Portuguese Case

    ERIC Educational Resources Information Center

    Magalhaes, Antonio; Veiga, Amelia; Amaral, Alberto; Sousa, Sofia; Ribeiro, Filipa

    2013-01-01

    The implementation of the governance reform of Portuguese higher education has been developed under the influence of "new public management" resulting in the loss of collegial governance. Additionally, the need for meta-governance of the higher education system and institutions to monitor institutional performance against policy…

  18. Factors Influencing the Use of Information and Communication Technology (ICT) in Teaching and Learning Computer Studies in Ohaukwu Local Government Area of Ebonyi State-Nigeria

    ERIC Educational Resources Information Center

    Agbo, Igwe Sylvester

    2015-01-01

    Research studies in the past years show that Information and Communication Technology is an effective means for boasting educational opportunities, but most teachers neither use this technology as an instructional delivery system nor integrate technology into their curriculum. Studies reveal a number of factors influencing teachers' decisions to…

  19. The Influence of E-Learning on Individual and Collective Empowerment in the Public Sector: An Empirical Study of Korean Government Employees

    ERIC Educational Resources Information Center

    Hur, Mann Hyung; Im, Yeonwook

    2013-01-01

    Our study explores the influence of e-learning on individual and collective empowerment by using data collected from e-learning class participants of Korea's Cyber-Education Center. For the survey, a questionnaire was sent to each of the 41 central ministries' education and training officers (ETO) via email. The ETOs distributed the questionnaire…

  20. Subsurface Flow and Transport: A Stochastic Approach

    NASA Astrophysics Data System (ADS)

    Desbarats, Alexandre

    Anyone who has examined core or petrophysical logs from well bores has wondered at the rhythmic successions of sedimentary fades and has puzzled at their sudden disruption or reappearance. Such wonderment is no doubt shared by those who have stood at a quarry face gazing up at the intricate hierarchy of depositional patterns and the varied textures of sediments. A fortunate few have even slogged along a mine drift and observed at close hand the perplexing relationship between the geological fabric of a rock mass and occurrences of groundwater inflow. Happily, the heterogeneity of geological materials is now widely recognized and efforts over the last 20 years have been concerned with its incorporation into models of fluid flow and solute transport in the subsurface. These research efforts are, at least in part, driven by acute societal concerns over the contamination of groundwater resources and proposed plans for the disposal of nuclear and other toxic wastes in the subsurface.

  1. Microbial methanogenesis in subsurface oil and coal.

    PubMed

    Meslé, Margaux; Dromart, Gilles; Oger, Philippe

    2013-11-01

    It is now clear that active methanogens are present in the deep-subsurface. This paper reviews microbial population structures and the biodegradation of organic compounds to methane in situ within oil reservoirs and coal deposits. It summarizes our current knowledge of methanogenes and methanogenesis, fermenters, synthrophs and microbial metabolism of complex organic compounds in these two widely occurring organic-rich subsurface environments. This review is not intended to be an exhaustive report of microbial diversity. Rather, it illustrates the similarities and differences between the two environments with specific examples, from the nature of the organic molecules to the methanogenic metabolic pathways and the structure of the microbial populations to demonstrate that widely diverging microbial populations show surprisingly similar metabolic capabilities.

  2. Subsurface discontinuity detection by microwave radiometry.

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Edgerton, A. T.

    1971-01-01

    Brief description of a joint program undertaken near Austin and San Antonio, Tex., to detect the presence of subsurface voids such as caverns and tunnels by microwave radiometry. Mi crowave radiometric temperature measurements using both vertical and horizontal polarization were taken with fixed-view angle traverses across three sites at two locations. No unambiguous correlation between the microwave temperature contours and the subsurface voids was observed at either location, but a correlation between microwave temperature and moisture patterns was observed at both locations. The large microwave temperature anomalies observed at all three sites indicated a sensitivity to near-surface structure and moisture distribution. A close correlation was noted between low soil-bearing strength values and the tunnel location at the San Antonio site.

  3. Radargrams Indicating Ice-Rich Subsurface Deposit

    NASA Image and Video Library

    2016-11-22

    These two images show data acquired by the Shallow Radar (SHARAD) instrument while passing over two ground tracks in a part of Mars' Utopia Planitia region where the orbiting, ground-penetrating radar detected subsurface deposits rich in water ice. The instrument on NASA's Mars Reconnaissance Orbiter emits radio waves and times their echo off of radio-reflective surfaces and interfaces on Mars. The white arrows indicate a subsurface reflector interpreted as the bottom of the ice-rich deposit. The deposit is about as large in area as the state of New Mexico and contains about as much water as Lake Superior. The horizontal scale bar indicates 40 kilometers (25 miles) along the ground track of the radar, as flown by the orbiter overhead. The vertical scale bar indicates a return time of one microsecond for the reflected radio signal, equivalent to a distance of about 90 meters (295 feet). http://photojournal.jpl.nasa.gov/catalog/PIA21137

  4. Modeling gas transport in the Martian subsurface

    NASA Astrophysics Data System (ADS)

    Gloesener, Elodie; Karatekin, Özgür; Dehant, Véronique

    2015-04-01

    Modeling gas transport through Martian subsurface and outgassing processes is essential in the study of atmospheric evolution of Mars. We present an overview of gas transport in Martian soil focusing on water vapor and methane diffusion to explain the recent observations of methane in Martian atmosphere with a diffusive transport model. The range of parameters that have the largest effect on transport in Martian conditions is investigated. Among the possible sources of methane, clathrate hydrates destabilization is one potential mechanism. Hydrate stability zone in subsurface is also investigated. In 2016, ExoMars Trace Gas Orbiter (TGO) will have the capabilities to detect and characterize trace gases in Martian atmosphere and will bring additional information to validate the different possible outgassing scenarios.

  5. Spreadsheet log analysis in subsurface geology

    USGS Publications Warehouse

    Doveton, J.H.

    2000-01-01

    Most of the direct knowledge of the geology of the subsurface is gained from the examination of core and drill-cuttings recovered from boreholes drilled by the petroleum and water industries. Wireline logs run in these same boreholes generally have been restricted to tasks of lithostratigraphic correlation and thee location of hydrocarbon pay zones. However, the range of petrophysical measurements has expanded markedly in recent years, so that log traces now can be transformed to estimates of rock composition. Increasingly, logs are available in a digital format that can be read easily by a desktop computer and processed by simple spreadsheet software methods. Taken together, these developments offer accessible tools for new insights into subsurface geology that complement the traditional, but limited, sources of core and cutting observations.

  6. Actinobacterial diversity across a marine transgression in the deep subsurface off Shimokita Peninsula, Japan

    NASA Astrophysics Data System (ADS)

    Harrison, B. K.; Bailey, J. V.

    2013-12-01

    Sediment horizons represent a significant - but not permanent - barrier to microbial transport. Cells commonly attach to mineral surfaces in unconsolidated sediments. However, by taxis, growth, or passive migration under advecting fluids, some portion of the microbial community may transgress sedimentary boundaries. Few studies have attempted to constrain such transport of community signatures in the marine subsurface and its potential impact on biogeography. Integrated Ocean Drilling Program (IODP) Expedition 337 off the Shimokita Peninsula recovered sediments over a greater than 1km interval representing a gradual decrease of terrestrial influence, from tidal to continental shelf depositional settings. This sequence represents a key opportunity to link subsurface microbial communities to lithological variability and investigate the permanence of community signatures characteristic of distinct depositional regimes. The phylogenetic connectivity between marine and terrestrially-influenced deposits may demonstrate to what degree sediments offer a substantial barrier to cell transport in the subsurface. Previous work has demonstrated that the Actinobacterial phylum is broadly distributed in marine sediments (Maldonado et al., 2005), present and active in the deep subsurface (Orsi et al., 2013), and that marine and terrestrial lineages may potentially be distinguished by 16S rRNA gene sequencing (e.g. Prieto-Davó et al., 2013). We report on Actinobacteria-specific 16S rRNA gene diversity recovered between 1370 and 2642 mbsf with high-throughput sequencing using the Illumina MiSeq platform, as well as selective assembly and analysis of environmental clone libraries.

  7. Surface Signature of Subsurface-Intensified Vortices

    NASA Astrophysics Data System (ADS)

    Ciani, D.; Carton, X. J.; Chapron, B.; Bashmachnikov, I.

    2014-12-01

    The ocean at mesoscale (20-200 km) and submesoscale (0.5-20km) is highly populated by vortices. These recirculating structures are more energetic than the mean flow, they trap water masses from their origin 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 (0-1500m), and are presently investigated by means of model outputs, in-situ 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 satellite 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 QG theory, we could describe the theoretical altimetric signature of non-drifting and of drifting subsurface eddies. Numerical experiments, using both coupled QG-SQG 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 eddy characteristics (radius, depth, thickness, velocity) were varied, 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), is a first step towards systematic and synoptic detection of subsurface vortices.

  8. Metalliferous Biosignatures for Deep Subsurface Microbial Activity

    NASA Astrophysics Data System (ADS)

    Parnell, John; Brolly, Connor; Spinks, Sam; Bowden, Stephen

    2016-03-01

    The interaction of microbes and metals is widely assumed to have occurred in surface or very shallow subsurface environments. However new evidence suggests that much microbial activity occurs in the deep subsurface. Fluvial, lacustrine and aeolian `red beds' contain widespread centimetre-scale reduction spheroids in which a pale reduced spheroid in otherwise red rocks contains a metalliferous core. Most of the reduction of Fe (III) in sediments is caused by Fe (III) reducing bacteria. They have the potential to reduce a range of metals and metalloids, including V, Cu, Mo, U and Se, by substituting them for Fe (III) as electron acceptors, which are all elements common in reduction spheroids. The spheroidal morphology indicates that they were formed at depth, after compaction, which is consistent with a microbial formation. Given that the consequences of Fe (III) reduction have a visual expression, they are potential biosignatures during exploration of the terrestrial and extraterrestrial geological record. There is debate about the energy available from Fe (III) reduction on Mars, but the abundance of iron in Martian soils makes it one of the most valuable prospects for life there. Entrapment of the microbes themselves as fossils is possible, but a more realistic target during the exploration of Mars would be the colour contrasts reflecting selective reduction or oxidation. This can be achieved by analysing quartz grains across a reduction spheroid using Raman spectroscopy, which demonstrates its suitability for life detection in subsurface environments. Microbial action is the most suitable explanation for the formation of reduction spheroids and may act as metalliferous biosignatures for deep subsurface microbial activity.

  9. Subsurface materials management and containment system

    DOEpatents

    Nickelson, Reva A.; Richardson, John G.; Kosteinik, Kevin M.; Sloan, Paul A.

    2004-07-06

    Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

  10. Subsurface materials management and containment system

    DOEpatents

    Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

    2006-10-17

    Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

  11. Drill Embedded Nanosensors For Planetary Subsurface Exploration

    NASA Technical Reports Server (NTRS)

    Li, Jing

    2014-01-01

    We have developed a carbon nanotube (CNT) sensor for water vapor detection under Martian Conditions and the miniaturized electronics can be embedded in the drill bit for collecting sensor data and transmit it to a computer wirelessly.This capability will enable the real time measurement of ice during drilling. With this real time and in-situ measurement, subsurface ice detection can be easy, fast, precise and low cost.

  12. Spatiotemporal variability in peatland subsurface methane dynamics

    NASA Astrophysics Data System (ADS)

    Strack, M.; Waddington, J. M.

    2008-06-01

    Peatlands are large natural sources of atmospheric methane (CH4). While many studies have measured CH4 emissions to the atmosphere, less is known about the stock and residence time of subsurface CH4. In this study we examined dissolved CH4 concentration in near-surface peatland pore waters of a poor fen near Québec City, Canada, in order to (1) investigate the variability in and potential controls on these concentrations and (2) combine measured dissolved CH4 concentration with estimated bubble CH4 stock and measured CH4 fluxes to estimate the mean residence time of subsurface CH4. Concentrations ranged from 1 to 450 μM during both study seasons. Depth profiles were generally consistent at one location within the peatland throughout the sampling period but varied between locations. Patterns with depth were not well correlated to pore water pH or EC; however, changes in CH4 concentration through time in the upper 30 cm were related to temperature and water table at some locations. Depth profiles taken at 2- to 5-cm intervals revealed discrete concentration "spikes" which were often maintained throughout the season and are likely related to bubble CH4 dynamics. Estimated subsurface CH4 stocks indicate that even when relatively low bubble volume (5% of peat volume) is assumed, bubble CH4 accounted for greater than half of total stocks. Calculated mean residence times were 28-120 days. This implies that CH4 flux may lag changes in water table and temperature which happen on shorter timescales (hours or days). To improve our description of subsurface CH4 stocks, links between dissolved and bubble CH4 stocks and peatland CH4 residence time, coincident measurement of pore water CH4 concentrations, entrapped gas content and composition, diffusive CH4 flux, and ebullition are required.

  13. Metalliferous Biosignatures for Deep Subsurface Microbial Activity.

    PubMed

    Parnell, John; Brolly, Connor; Spinks, Sam; Bowden, Stephen

    2016-03-01

    The interaction of microbes and metals is widely assumed to have occurred in surface or very shallow subsurface environments. However new evidence suggests that much microbial activity occurs in the deep subsurface. Fluvial, lacustrine and aeolian 'red beds' contain widespread centimetre-scale reduction spheroids in which a pale reduced spheroid in otherwise red rocks contains a metalliferous core. Most of the reduction of Fe (III) in sediments is caused by Fe (III) reducing bacteria. They have the potential to reduce a range of metals and metalloids, including V, Cu, Mo, U and Se, by substituting them for Fe (III) as electron acceptors, which are all elements common in reduction spheroids. The spheroidal morphology indicates that they were formed at depth, after compaction, which is consistent with a microbial formation. Given that the consequences of Fe (III) reduction have a visual expression, they are potential biosignatures during exploration of the terrestrial and extraterrestrial geological record. There is debate about the energy available from Fe (III) reduction on Mars, but the abundance of iron in Martian soils makes it one of the most valuable prospects for life there. Entrapment of the microbes themselves as fossils is possible, but a more realistic target during the exploration of Mars would be the colour contrasts reflecting selective reduction or oxidation. This can be achieved by analysing quartz grains across a reduction spheroid using Raman spectroscopy, which demonstrates its suitability for life detection in subsurface environments. Microbial action is the most suitable explanation for the formation of reduction spheroids and may act as metalliferous biosignatures for deep subsurface microbial activity.

  14. Radionuclide Sensors for Subsurface Water Monitoring

    SciTech Connect

    Timothy DeVol

    2006-06-30

    Contamination of the subsurface by radionuclides is a persistent and vexing problem for the Department of Energy. These radionuclides must be measured in field studies and monitoed in the long term when they cannot be removed. However, no radionuclide sensors existed for groundwater monitoring prior to this team's research under the EMSP program Detection of a and b decays from radionuclides in water is difficult due to their short ranges in condensed media.

  15. Contaminant Transport Through Subsurface Material from the DOE Hanford Reservation

    SciTech Connect

    Pace, M.N.; Mayes, M.A.; Jardine, P.M.; Fendorf, S.E.; Nehlhorn, T.L.; Yin, X.P.; Ladd, J.; Teerlink, J.; Zachara, J.M.

    2003-03-26

    Accelerated migration of contaminants in the vadose zone has been observed beneath tank farms at the U.S. Department of Energy's Hanford Reservation. This paper focuses on the geochemical processes controlling the fate and transport of contaminants in the sediments beneath the Hanford tank farms. Laboratory scale batch sorption experiments and saturated transport experiments were conducted using reactive tracers U(VI), Sr, Cs, Co and Cr(VI) to investigate geochemical processes controlling the rates and mechanisms of sorption to Hanford subsurface material. Results indicate that the rate of sorption is influenced by changes in solution chemistry such as ionic strength, pH and presence of competing cations. Sediment characteristics such as mineralogy, iron content and cation/anion exchange capacity coupled with the dynamics of flow impact the number of sites available for sorption. Investigative approaches using a combination of batch and transport experiments will contribute to the conceptual and Hanford vadose zone.

  16. Laser surface and subsurface modification of sapphire using femtosecond pulses

    NASA Astrophysics Data System (ADS)

    Eberle, G.; Schmidt, M.; Pude, F.; Wegener, K.

    2016-08-01

    Two methods to process sapphire using femtosecond laser pulses are demonstrated, namely ablation (surface), and in-volume laser modification followed by wet etching (subsurface). Firstly, the single and multipulse ablation threshold is determined and compared with previous literature results. A unique application of ablation is demonstrated by modifying the entrance aperture of water jet orifices. Laser ablation exhibits advantages in terms of geometric flexibility and resolution, however, defects in the form of edge outbreaks and poor surface quality are evident. Secondly, the role of material transformation, polarisation state and formation of multi-focus structures after in-volume laser modification is investigated in order to explain their influence during the wet etching process. Laser scanning and electron microscopy as well as electron backscatter diffraction measurements supported by ion beam polishing are used to better understand quality and laser-material interactions of the two demonstrated methods of processing.

  17. Activation of Peroxymonosulfate by Subsurface Minerals

    NASA Astrophysics Data System (ADS)

    Yu, Miao; Teel, Amy L.; Watts, Richard J.

    2016-08-01

    In situ chemical oxidation (ISCO) has become a widely used technology for the remediation of soil and groundwater. Although peroxymonosulfate is not a common oxidant source for ISCO, its chemical structure is similar to the ISCO reagents hydrogen peroxide and persulfate, suggesting that peroxymonosulfate may have the beneficial properties of each of these oxidants. Peroxymonosulfate activation in the presence of subsurface minerals was examined as a basis for ISCO, and possible reactive species (hydroxyl radical, sulfate radical, and reductants + nucleophiles) generated in the mineral-activated peroxymonosulfate systems were investigated. Rates of peroxymonosulfate decomposition and generation rates of reactive species were studied in the presence of three iron oxides, one manganese oxide, and three soil fractions. The iron oxide hematite-activated peroxymonosulfate system most effectively degraded the hydroxyl radical probe nitrobenzene. Reductants + nucleophiles were not generated in mineral-activated peroxymonosulfate systems. Use of the probe compound anisole in conjunction with scavengers demonstrated that both sulfate radical and hydroxyl radical are generated in mineral-activated peroxymonosulfate systems. In order to confirm the activation of peroxymonosulfate by subsurface minerals, one natural soil and associated two soil fractions were evaluated as peroxymonosulfate catalysts. The natural soil did not effectively promote the generation of oxidants; however, the soil organic matter was found to promote the generation of reductants + nucleophiles. The results of this research show that peroxymonosulfate has potential as an oxidant source for ISCO applications, and would be most effective in treating halogenated contaminants when soil organic matter is present in the subsurface.

  18. Subsurface urban heat islands in German cities.

    PubMed

    Menberg, Kathrin; Bayer, Peter; Zosseder, Kai; Rumohr, Sven; Blum, Philipp

    2013-01-01

    Little is known about the intensity and extension of subsurface urban heat islands (UHI), and the individual role of the driving factors has not been revealed either. In this study, we compare groundwater temperatures in shallow aquifers beneath six German cities of different size (Berlin, Munich, Cologne, Frankfurt, Karlsruhe and Darmstadt). It is revealed that hotspots of up to +20K often exist, which stem from very local heat sources, such as insufficiently insulated power plants, landfills or open geothermal systems. When visualizing the regional conditions in isotherm maps, mostly a concentric picture is found with the highest temperatures in the city centers. This reflects the long-term accumulation of thermal energy over several centuries and the interplay of various factors, particularly in heat loss from basements, elevated ground surface temperatures (GST) and subsurface infrastructure. As a primary indicator to quantify and compare large-scale UHI intensity the 10-90%-quantile range UHII(10-90) of the temperature distribution is introduced. The latter reveals, in comparison to annual atmospheric UHI intensities, an even more pronounced heating of the shallow subsurface. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Subsurface barrier integrity verification using perfluorocarbon tracers

    SciTech Connect

    Sullivan, T.M.; Heiser, J.; Milian, L.; Senum, G.

    1996-12-01

    Subsurface barriers are an extremely promising remediation option to many waste management problems. Gas phase tracers include perfluorocarbon tracers (PFT`s) and chlorofluorocarbon tracers (CFC`s). Both have been applied for leak detection in subsurface systems. The focus of this report is to describe the barrier verification tests conducted using PFT`s and analysis of the data from the tests. PFT verification tests have been performed on a simulated waste pit at the Hanford Geotechnical facility and on an actual waste pit at Brookhaven National Laboratory (BNL). The objective of these tests were to demonstrate the proof-of-concept that PFT technology can be used to determine if small breaches form in the barrier and for estimating the effectiveness of the barrier in preventing migration of the gas tracer to the monitoring wells. The subsurface barrier systems created at Hanford and BNL are described. The experimental results and the analysis of the data follow. Based on the findings of this study, conclusions are offered and suggestions for future work are presented.

  20. Resonant seismic emission of subsurface objects

    SciTech Connect

    Korneev, Valeri A.

    2009-04-15

    Numerical modeling results and field data indicate that some contrasting subsurface objects (such as tunnels, caves, pipes, filled pits, and fluid-filled fractures) are capable of generating durable resonant oscillations after trapping seismic energy. These oscillations consist of surface types of circumferential waves that repeatedly propagate around the object. The resonant emission of such trapped energy occurs primarily in the form of shear body waves that can be detected by remotely placed receivers. Resonant emission reveals itself in the form of sharp resonant peaks for the late parts of the records, when all strong direct and primary reflected waves are gone. These peaks were observed in field data for a buried barrel filled with water, in 2D finite-difference modeling results, and in the exact canonical solution for a fluid-filled sphere. A computed animation for the diffraction of a plane wave upon a low-velocity elastic sphere confirms the generation of resonances by durable surface waves. Resonant emission has characteristic quasi-hyperbolic traveltime patterns on shot gathers. The inversion of these patterns can be performed in the frequency domain after muting the strong direct and primary scattered waves. Subsurface objects can be detected and imaged at a single resonance frequency without an accurate knowledge of source trigger time. The imaging of subsurface objects requires information about the shear velocity distribution in an embedding medium, which can be done interactively during inversion.

  1. Subsurface ocean changes during Heinrich events

    NASA Astrophysics Data System (ADS)

    Hoffman, J. S.; Clark, P.; Mix, A. C.; Haley, B. A.

    2013-12-01

    Heinrich events represent episodic, large-scale instabilities of the Laurentide Ice Sheet (LIS) that are contemporaneous with global climate change. Commonly attributed to an internally triggered instability of the LIS, the occurrence of Heinrich events during the maximum expression of the bipolar seesaw instead suggests a climate trigger external to the ice sheet. Results from coupled ocean-atmosphere models of varying complexity and recent coupled ocean-ice sheet models imply that subsurface warming of intermediate ocean waters (750-1500m) in response to a reduction of the Atlantic Meridional Overturning Circulation (AMOC) may destabilize the grounding lines of marine-based sectors of the eastern LIS, causing a Heinrich event. One previous study from the Labrador Sea showed 2-6°C of warming at intermediate depths prior to several Heinrich events. We will present preliminary surface- and intermediate-depth temperature reconstructions from planktic and benthic foraminifera bracketing Heinrich event 1 in five sediment cores raised from the Labrador Sea and Reykjanes Ridge to evaluate the spatial and temporal coherence of subsurface warming in the northwestern Atlantic. Results will help characterize the amplitude, timing, and spatial expression of western North Atlantic subsurface ocean changes with respect to Heinrich event 1, and potentially other Heinrich events in the same cores.

  2. Environmental Electrokinetics for a sustainable subsurface.

    PubMed

    Lima, A T; Hofmann, A; Reynolds, D; Ptacek, C J; Van Cappellen, P; Ottosen, L M; Pamukcu, S; Alshawabekh, A; O'Carroll, D M; Riis, C; Cox, E; Gent, D B; Landis, R; Wang, J; Chowdhury, A I A; Secord, E L; Sanchez-Hachair, A

    2017-08-01

    Soil and groundwater are key components in the sustainable management of the subsurface environment. Source contamination is one of its main threats and is commonly addressed using established remediation techniques such as in-situ chemical oxidation (ISCO), in-situ chemical reduction (ISCR; most notably using zero-valent iron [ZVI]), enhanced in-situ bioremediation (EISB), phytoremediation, soil-washing, pump-and-treat, soil vapour extraction (SVE), thermal treatment, and excavation and disposal. Decades of field applications have shown that these techniques can successfully treat or control contaminants in higher permeability subsurface materials such as sands, but achieve only limited success at sites where low permeability soils, such as silts and clays, prevail. Electrokinetics (EK), a soil remediation technique mostly recognized in in-situ treatment of low permeability soils, has, for the last decade, been combined with more conventional techniques and can significantly enhance the performance of several of these remediation technologies, including ISCO, ISCR, EISB and phytoremediation. Herein, we discuss the use of emerging EK techniques in tandem with conventional remediation techniques, to achieve improved remediation performance. Furthermore, we highlight new EK applications that may come to play a role in the sustainable treatment of the contaminated subsurface. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Satellite-derived subsurface urban heat island.

    PubMed

    Zhan, Wenfeng; Ju, Weimin; Hai, Shuoping; Ferguson, Grant; Quan, Jinling; Tang, Chaosheng; Guo, Zhen; Kong, Fanhua

    2014-10-21

    The subsurface urban heat island (SubUHI) is one part of the overall UHI specifying the relative warmth of urban ground temperatures against the rural background. To combat the challenge on measuring extensive underground temperatures with in situ instruments, we utilized satellite-based moderate-resolution imaging spectroradiometer data to reconstruct the subsurface thermal field over the Beijing metropolis through a three-time-scale model. The results show the SubUHI's high spatial heterogeneity. Within the depths shallower than 0.5 m, the SubUHI dominates along the depth profiles and analyses imply the moments for the SubUHI intensity reaching first and second extremes during a diurnal temperature cycle are delayed about 3.25 and 1.97 h per 0.1 m, respectively. At depths shallower than 0.05 m in particular, there is a subsurface urban cool island (UCI) in spring daytime, mainly owing to the surface UCI that occurs in this period. At depths between 0.5 and 10 m, the time for the SubUHI intensity getting to its extremes during an annual temperature cycle is lagged 26.2 days per meter. Within these depths, the SubUHI prevails without exception, with an average intensity of 4.3 K, varying from 3.2 to 5.3 K.

  4. Chemical inversion in the subsurface hydrosphere

    SciTech Connect

    Yezhov, Yu.A.

    1980-09-01

    A quite common nature of chemical inversion in subsurface hydrosphere is shown in examples of several oil- and gas-bearing regions of the USSR. In particular, when the data of sampling from deep wells of the Volgo-Urals, Mangyshlak, and Western Turkmenian regions were compared, it became obvious that the composite chemical profile of subsurface hydrosphere consists of a vertical alternation of three zones: of increasing (I-II-IIIa genetic types of subsurface waters), maximum (IIIb), and decreasing water mineralization (III'a-II'-I'). The depth of occurrence of the lower inversion branch of zonality depends on the geotectonic activity at depth. It is closer to the Earth's surface in regions of Alpine tectogenesis, whereas in regions of ancient folding it lies at great depths which have not yet been reached by most deep wells. The formation of the inversion zone in the Earth's crust is connected with penetration from below ascending demineralized fluids of sodium bicarbonate type (I'). The latter is due to the presence at great depths of large quantities of free carbonic acid which is involved in hydrolytic processes of decomposition of sodium-containing minerals and produces sodium-type waters.

  5. Subsurface heat flow in an urban environment

    NASA Astrophysics Data System (ADS)

    Ferguson, Grant; Woodbury, Allan D.

    2004-02-01

    The subsurface temperature field beneath Winnipeg, Canada, is significantly different from that of the surrounding rural areas. Downward heat flow to depths as great as 130 m has been noted in some areas beneath the city and groundwater temperatures in a regional aquifer have risen by as much as 5°C in some areas. Numerical simulation of heat transport supports the conjecture that these temperature changes can be largely attributed to heat loss from buildings and the temperature at any given point is sensitive to the distance from and the age of any buildings. The effect is most noticable when buildings are closely spaced, which is typical of urban areas. Temperature measurements in areas more than a few hundred meters away from any heated structure were only a few tenths of a degree Celsius greater than those observed outside the city, suggesting that other reasons for increases in subsurface temperature, such as changes in surface cover or climate change, may be responsible for some of the some of the observed increase in temperatures. These sources of additional heat to the subsurface make it difficult to resolve information on past climates from temperatures measured in boreholes and monitoring wells. In some areas, the temperature increases may also have an impact on geothermal energy resources. This impact might be in the form of an increase in heat pump efficiency or in the case of the Winnipeg area, a decrease in the efficiency of direct use of groundwater for cooling.

  6. Hydrogen Utilization Potential in Subsurface Sediments

    PubMed Central

    Adhikari, Rishi R.; Glombitza, Clemens; Nickel, Julia C.; Anderson, Chloe H.; Dunlea, Ann G.; Spivack, Arthur J.; Murray, Richard W.; D'Hondt, Steven; Kallmeyer, Jens

    2016-01-01

    Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H2ases to successively higher concentrations of H2 in successively deeper zones. PMID:26858697

  7. Hydrogen Utilization Potential in Subsurface Sediments.

    PubMed

    Adhikari, Rishi R; Glombitza, Clemens; Nickel, Julia C; Anderson, Chloe H; Dunlea, Ann G; Spivack, Arthur J; Murray, Richard W; D'Hondt, Steven; Kallmeyer, Jens

    2016-01-01

    Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H2ases to successively higher concentrations of H2 in successively deeper zones.

  8. Influence of Subsurface Cracks on Laser Induced Surface Damage

    SciTech Connect

    Feit, M D; Rubenchik, A M

    2003-11-07

    Cracks can affect laser damage susceptibility in three ways. These are field intensification due to interference, enhanced absorption due to trapped material in the cracks, and increased mechanical weakness. Enhanced absorption is the most important effect.

  9. A Direct Method of Hydraulic Conductivity Structure Identification for Subsurface Transport Modeling

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Jiao, J.

    2016-12-01

    Solute transport in aquifers is strongly influenced by the spatial distribution of subsurface hydraulic conductivity (K), while limited drilling in data-sparse environments typically results in lack of data characterizing both the K and the in-situ fluid flow boundary conditions (BC). To characterize such environments, we present an efficient direct inverse method to simultaneously identify aquifer K pattern, its values, and the flow field. The method ensures fluid flow continuity using local approximate solutions of the governing equation conditioned to limited hydraulic measurements, while physics of the flow is enforced making the inverse problem well-posed. A single system of equations is assembled and solved, from which parameters and BC can be simultaneously estimated. For problems with irregular and regular K distributions, inversion is demonstrated for different measurement types, quality, and quantity. When measurement error is increased, the estimated K pattern is largely insensitive to the error, although the inverted flow field suffers greater inaccuracy. Local conductivity and Darcy flux measurements are found to have similar information content, although subtle differences exist in the inverted flow fields when long-term contaminant release is simulated. Local conductivity measurements lead to better identification of conductivity pattern, values, and the hydraulic head field; Darcy flux measurements lead to more accurate estimation of the velocity field and thus improved transport predictions. Overall, the velocity fields estimated based on the hydraulic data can lead to reasonable predictions of contaminant migration and breakthrough under unknown aquifer BC. We further argue that the goal of pattern inversion is to recover a sufficient level of detail to make transport prediction approximately accurate. Depending on the desired accuracy, fine-scale heterogeneity can be recovered only at increased characterization cost. Future work will (1) evaluate

  10. Foraminiferal radiocarbon record of northeast Pacific decadal subsurface variability

    NASA Astrophysics Data System (ADS)

    Roach, Lydia D.; Charles, Christopher D.; Field, David B.; Guilderson, Thomas P.

    2013-09-01

    The decadal dynamics of the subsurface North Pacific Ocean are largely inaccessible beyond sparse instrumental observations spanning the last 20 years. Here we present a ˜200 year long record of benthic foraminiferal radiocarbon (Δ14C), extracted at biennial resolution from the annually laminated sediments at the Santa Barbara Basin (SBB) depocenter (˜600 m). The close match between core top benthic foraminiferal Δ14C values and the Δ14C of seawater dissolved inorganic carbon (DIC) suggests that benthic foraminifera faithfully capture the bottom water radiocarbon concentrations, as opposed to that of the deeper (>0.5 cm) sediment porewater zone. The full time series of benthic foraminiferal Δ14C displays significant variability on decadal timescales, with excursions on the order of 40‰. These excursions are overprinted by a unidirectional trend over the late 20th century that likely reflects the sedimentary incorporation of bomb radiocarbon (via remineralized particulate organic carbon). We isolate this trend by means of a one-dimensional oxidation model, which considers the possible contribution of remineralized particles to the total ambient carbon pool. This oxidation model also considers the possible influence of carbon with a variety of sources (ages). Though variable oxidation of preaged carbon could exert a strong influence on benthic foraminiferal radiocarbon variability, the totality of evidence points to the vertical density structure along the Southern California Margin (SCM) as the primary driver of the SBB benthic foraminiferal Δ14C record. For example, intervals characterized by significantly lower Δ14C values correspond to periods of enhanced upwelling and subsurface equatorward flow along the SCM.

  11. CenSSIS: the first year of an engineering research center for subsurface sensing and imaging

    NASA Astrophysics Data System (ADS)

    Silevitch, Michael B.

    2001-11-01

    Historically, the communities of engineers and scientists who image objects under the ground, under the ocean, inside the body, and inside the cell, have had relatively little contact, despite dealing with similar issues and often using similar mathematical models and algorithms. CenSSIS, the Center for Subsurface Sensing and Imaging Systems, is an NSF Engineering Research Center, developed to bring these seemingly disparate fields together. Conceived at Northeastern University, the Center now has four university partners, four affiliates, and a growing number of corporate and government sponsors. CenSSIS was established to solve real--world problems in these and other fields, to spark revolutionary advances by developing a unified framework for subsurface sensing and imaging systems, and to immerse students and researchers in a multi--disciplinary teaching and learning environment. Already this effort has begun to bear fruit. Here we report on the first full year of activity as an Engineering Research Center.

  12. A-TOUGH: A multimedia fluid-flow/energy-transport model for fully- coupled atmospheric-subsurface interactions

    SciTech Connect

    Montazer, P.; Hammermeister, D.; Ginanni, J.

    1994-12-31

    The long-term effect of changes in atmospheric climatological conditions on subsurface hydrological conditions in the unsaturated zone in and environments is an important factor in defining the performance of a high-level and low-level radioactive waste repositories in geological environment. Computer simulation coupled with paleohydrological studies can be used to understand and quantify the potential impact of future climatological conditions on repository performance. A-TOUGH efficiently simulates (given current state-of-the-art technology) the physical processes involved in the near-surface atmosphere and its effect on subsurface conditions. This efficiency is due to the numerical techniques used in TOUGH and the efficient computational techniques used in V-TOUGH to solve non-linear thermodynamic equations that govern the flux of vapor and energy within subsurface porous and fractured media and between these media and the atmosphere.

  13. Untangling the effects of urban development on subsurface storage in Baltimore

    NASA Astrophysics Data System (ADS)

    Bhaskar, Aditi S.; Welty, Claire; Maxwell, Reed M.; Miller, Andrew J.

    2015-02-01

    The impact of urban development on surface flow has been studied extensively over the last half century, but effects on groundwater systems are still poorly understood. Previous studies of the influence of urban development on subsurface storage have not revealed any consistent pattern, with results showing increases, decreases, and negligible change in groundwater levels. In this paper, we investigated the effects of four key features that impact subsurface storage in urban landscapes. These include reduced vegetative cover, impervious surface cover, infiltration and inflow (I&I) of groundwater and storm water into wastewater pipes, and other anthropogenic recharge and discharge fluxes including water supply pipe leakage and well and reservoir withdrawals. We applied the integrated groundwater-surface water-land surface model ParFlow.CLM to the Baltimore metropolitan area. We compared the base case (all four features) to simulations in which an individual urban feature was removed. For the Baltimore region, the effect of infiltration of groundwater into wastewater pipes had the greatest effect on subsurface storage (I&I decreased subsurface storage 11.1% relative to precipitation minus evapotranspiration after 1 year), followed by the impact of water supply pipe leakage and lawn irrigation (combined anthropogenic discharges and recharges led to a 7.4% decrease) and reduced vegetation (1.9% increase). Impervious surface cover led to a small increase in subsurface storage (0.56% increase) associated with decreased groundwater discharge as base flow. The change in subsurface storage due to infiltration of groundwater into wastewater pipes was largest despite the smaller spatial extent of surface flux modifications, compared to other features.

  14. Reactive transport benchmarks for subsurface environmental simulation

    SciTech Connect

    Steefel, Carl I.; Yabusaki, Steven B.; Mayer, K. U.

    2015-06-01

    Over the last 20 years, we have seen firsthand the evolution of multicomponent reactive transport modeling and the expanding range and increasing complexity of subsurface applications it is being used to address. There is a growing reliance on reactive transport modeling (RTM) to address some of the most compelling issues facing our planet: climate change, nuclear waste management, contaminant remediation, and pollution prevention. While these issues are motivating the development of new and improved capabilities for subsurface environmental modeling using RTM (e.g., biogeochemistry from cell-scale physiology to continental-scale terrestrial ecosystems, nonisothermal multiphase conditions, coupled geomechanics), there remain longstanding challenges in characterizing the natural variability of hydrological, biological, and geochemical properties in subsurface environments and limited success in transferring models between sites and across scales. An equally important trend over the last 20 years is the evolution of modeling from a service sought out after data has been collected to a multifaceted research approach that provides (1) an organizing principle for characterization and monitoring activities; (2) a systematic framework for identifying knowledge gaps, developing and integrating new knowledge; and (3) a mechanistic understanding that represents the collective wisdom of the participating scientists and engineers. There are now large multidisciplinary projects where the research approach is model-driven, and the principal product is a holistic predictive simulation capability that can be used as a test bed for alternative conceptualizations of processes, properties, and conditions. Much of the future growth and expanded role for RTM will depend on its continued ability to exploit technological advancements in the earth and environmental sciences. Advances in measurement technology, particularly in molecular biology (genomics), isotope fractionation, and high

  15. Subsurface Characterization of the San Jacinto Wetland Research Site

    NASA Astrophysics Data System (ADS)

    Leik, J.; Bonner, J.; Page, C.; Autenrieth, R.

    2004-05-01

    Investigations of surface/groundwater coupling for contaminant flux were conducted for the San Jacinto Wetland Research Facility (SJWRF). The site is located in a four-hectare wetland on the south bank of the San Jacinto River, near Houston, Texas. This groundwater/surface water interaction study was a component of a multiphase petroleum remediation program. To determine the fate of petroleum contamination, the shallow groundwater of a wetland was characterized. The study area consists of a small, tidally-influenced cove surrounded by an intertidal wetland area. It is usually submerged on a diurnal cycle, barring extreme weather or tidal events. A thin layer (20-30 cm) of low-permeability clayey silt typical of low energy deposition overlays well-graded medium-to-fine-grained sand approximately 2.5-3 m thick. This is underlain by highly impermeable clay. A few dispersed clay lenses were encountered at a depth of 1-1.5 m, but were the exception rather than the rule. The site is equipped with an automated data collection system that records weather and water quality data. It also is used to collect surface and groundwater data from the twelve piezometers surrounding the cove, three 3-D groundwater flow sensors, and two surface water depth sensors. The objective of this research was to characterize the hydraulic flow patterns in the shallow subsurface of the wetland, as the data generated from this characterization can be used to predict the movement of contaminants in the subsurface. By determining water quality parameters for the groundwater at the site, significant physical, chemical, and biological processes can be determined. Hydraulic and physical-chemical characterization of the SJWRF site will allow predictions as to the fate and transport of contaminants in the shallow subsurface. Slug Testing was performed in twelve wells located around the perimeter of the site to determine hydraulic conductivity. They were situated in four groups of three wells, with the

  16. Fracture Mechanics Analyses of Subsurface Defects in Reinforced Carbon-Carbon Joggles Subjected to Thermo-Mechanical Loads

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Raju, Ivatury S.; Song, Kyongchan

    2011-01-01

    Coating spallation events have been observed along the slip-side joggle region of the Space Shuttle Orbiter wing-leading-edge panels. One potential contributor to the spallation event is a pressure build up within subsurface voids or defects due to volatiles or water vapor entrapped during fabrication, refurbishment, or normal operational use. The influence of entrapped pressure on the thermo-mechanical fracture-mechanics response of reinforced carbon-carbon with subsurface defects is studied. Plane-strain simulations with embedded subsurface defects are performed to characterize the fracture mechanics response for a given defect length when subjected to combined elevated-temperature and subsurface-defect pressure loadings to simulate the unvented defect condition. Various subsurface defect locations of a fixed-length substrate defect are examined for elevated temperature conditions. Fracture mechanics results suggest that entrapped pressure combined with local elevated temperatures have the potential to cause subsurface defect growth and possibly contribute to further material separation or even spallation. For this anomaly to occur, several unusual circumstances would be required making such an outcome unlikely but plausible.

  17. Iberian Pyrite Belt Subsurface Life (IPBSL): searching for life in the Rio Tinto subsurface

    NASA Astrophysics Data System (ADS)

    Amils, R.; Gómez, F.; Prieto-Ballesteros, O.; Fernández-Remolar, D.; Parro, V.; Rodríguez-Manfredi, J. A.; Tornos-Arroyo, F.; Timmis, K.; Oggerin, M.; Sánchez-Román, M.; López, F. J.; Fernández, J. P.; Omoregie, E.; Puente-Sánchez, F.; García, M.; Rodríguez, N.

    2013-09-01

    The geomicrobiologica l characterization of Río Tinto (Iberian Pyrite Belt), has proven the importance of the iron and sulfur cycles in generating the extreme conditions of acidity and high concentration of heavy metals of the habitat. It has been hypothesized that the extreme conditions found in the Tinto basin are the product of the subsurface chemolithotrophic metabolism of microorganisms thriving on the high concentrat ion of metal sulfides of the IPB. To test this hypothesis, a drilling project (IPBSL) is currently under development to provide evidence of subsurface microbial activities and the potential resources to support them.

  18. Subsurface Tectonics and Pingos of Northern Alaska

    NASA Astrophysics Data System (ADS)

    Skirvin, S.; Casavant, R.; Burr, D.

    2008-12-01

    We describe preliminary results of a two-phase study that investigated links between subsurface structural and stratigraphic controls, and distribution of hydrostatic pingos on the central coastal plain of Arctic Alaska. Our 2300 km2 study area is underlain by a complete petroleum system that supports gas, oil and water production from 3 of the largest oil fields in North America. In addition, gas hydrate deposits exist in this area within and just below the permafrost interval at depths of 600 to 1800 feet below sea level. Phase 1 of the study compared locations of subsurface faults and pingos for evidence of linkages between faulting and pingo genesis and distribution. Several hundred discrete fault features were digitized from published data and georeferenced in a GIS database. Fault types were determined by geometry and sense of slip derived from well log and seismic maps. More than 200 pingos and surface sediment type associated with their locations were digitized from regional surficial geology maps within an area that included wire line and seismic data coverage. Beneath the pingos lies an assemblage of high-angle normal and transtensional faults that trend NNE and NW; subsidiary trends are EW and NNW. Quaternary fault reactivation is evidenced by faults that displaced strata at depths exceeding 3000 meters below sea level and intersect near-surface units. Unpublished seismic images and cross-section analysis support this interpretation. Kinematics and distribution of reactivated faults are linked to polyphase deformational history of the region that includes Mesozoic rift events, succeeded by crustal shortening and uplift of the Brooks Range to the south, and differential subsidence and segmentation of a related foreland basin margin beneath the study area. Upward fluid migration, a normal process in basin formation and fault reactivation, may play yet unrecognized roles in the genesis (e.g. fluid charging) of pingos and groundwater hydrology. Preliminary

  19. Effects of soil depth and subsurface flow along the subsurface topography on shallow landslide predictions at the site of a small granitic hillslope

    NASA Astrophysics Data System (ADS)

    Kim, Min Seok; Onda, Yuichi; Uchida, Taro; Kim, Jin Kwan

    2016-10-01

    Shallow landslides are affected by various conditions, including soil depth and subsurface flow via an increase in the pore water pressure. In this study, we evaluate the effect of soil depth and subsurface flow on shallow landslide prediction using the shallow landslide stability (SHALSTAB) model. Three detailed soil depth data-the average soil depth, weathered soil depth, and bedrock soil depth-were collected using a knocking pole test at a small hillslope site composed of granite in the Republic of Korea. The SHALSTAB model was applied to a ground surface topographic digital elevation model (DEM) using the three soil depths and upslope contributing area (SCA) assuming subsurface flow calculated from four DEMs: a ground surface topography (GSTO) DEM, weathered soil topography (WSTO) DEM, bedrock topography (BSTO) DEM, and low-level bedrock topography (EBSTO) DEM. The model performance was measured using a receiver operating characteristic (ROC) analysis. While evaluating the effect of the soil depth with SCA using GSTO DEM, it was found that the bedrock soil depth had higher prediction accuracy compared to that of the average soil depth or weathered soil depth. To evaluate the saturated subsurface flow between the soil and bedrock, SCAs calculated using WSTO and BSTO DEMs were applied. From these simulations, we found that SCA from BSTO DEM and the bedrock soil depth affect the shallow landslide prediction; however, these prediction effects are not significantly increased by large differences in the elevation (between the lowest and highest elevation values). Therefore, we considered the influence of the bedrock depression and SCA from EBSTO DEM. In applying SCA from EBSTO, the prediction accuracy was significantly increased compared to the other predictions. Our results demonstrate that the influence of the bedrock topography on the prediction of shallow landslides may be particularly significant at the scale of a hillslope.

  20. [Governance for health].

    PubMed

    Holčík, Jan

    2012-01-01

    New approaches to governance are driven by the changing nature of the challenges faced by 21st century societies. People, their health and capabilities are the key resources of a knowledge society. In the article the meaning of "governance for health" is explained and some methods of governance are presented. Governance for health will be implemented in the new European health policy - Health 2020.

  1. Public health governance: views of key stakeholders.

    PubMed

    Marks, L; Cave, S; Hunter, D J

    2010-01-01

    To identify views of key stakeholders on public health governance. Focus groups and interviews. Key national and regional stakeholders in England were invited to participate in focus groups. Three focus groups and four additional interviews were transcribed and a thematic analysis was carried out. Focus groups and interviewees identified points of transition in public health governance including changes in the notion of stewardship, governance across a local public health system and a shift from organizational governance to 'governance of place'. Different governance arrangements and approaches to governance can influence health outcomes through their impact on commissioning strategies, public health practice and performance management regimes. Failure to address these issues will hamper the development of a stewardship role in local organizations and across a local public health system. Copyright 2009 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  2. Activation of Peroxymonosulfate by Subsurface Minerals.

    PubMed

    Yu, Miao; Teel, Amy L; Watts, Richard J

    2016-08-01

    In situ chemical oxidation (ISCO) has become a widely used technology for the remediation of soil and groundwater. Although peroxymonosulfate is not a common oxidant source for ISCO, its chemical structure is similar to the ISCO reagents hydrogen peroxide and persulfate, suggesting that peroxymonosulfate may have the beneficial properties of each of these oxidants. Peroxymonosulfate activation in the presence of subsurface minerals was examined as a basis for ISCO, and possible reactive species (hydroxyl radical, sulfate radical, and reductants+nucleophiles) generated in the mineral-activated peroxymonosulfate systems were investigated. Rates of peroxymonosulfate decomposition and generation rates of reactive species were studied in the presence of three iron oxides, one manganese oxide, and three soil fractions. The iron oxide hematite-activated peroxymonosulfate system most effectively degraded the hydroxyl radical probe nitrobenzene. Reductants+nucleophiles were not generated in mineral-activated peroxymonosulfate systems. Use of the probe compound anisole in conjunction with scavengers demonstrated that both sulfate radical and hydroxyl radical are generated in mineral-activated peroxymonosulfate systems. In order to confirm the activation of peroxymonosulfate by subsurface minerals, one natural soil and associated two soil fractions were evaluated as peroxymonosulfate catalysts. The natural soil did not effectively promote the generation of oxidants; however, the soil organic matter was found to promote the generation of reductants + nucleophiles. The results of this research show that peroxymonosulfate has potential as an oxidant source for ISCO applications, and would be most effective in treating halogenated contaminants when soil organic matter is present in the subsurface. Copyright © 2016. Published by Elsevier B.V.

  3. Using Muons to Image the Subsurface.

    SciTech Connect

    Bonal, Nedra; Cashion, Avery Ted; Cieslewski, Grzegorz; Dorsey, Daniel J.; Foris, Adam; Miller, Timothy J.; Roberts, Barry L; Su, Jiann-Cherng; Dreesen, Wendi; Green, J. Andrew; Schwellenbach, David

    2016-11-01

    Muons are subatomic particles that can penetrate the earth 's crust several kilometers and may be useful for subsurface characterization . The absorption rate of muons depends on the density of the materials through which they pass. Muons are more sensitive to density variation than other phenomena, including gravity, making them beneficial for subsurface investigation . Measurements of muon flux rate at differing directions provide density variations of the materials between the muon source (cosmic rays and neutrino interactions) and the detector, much like a CAT scan. Currently, muon tomography can resolve features to the sub-meter scale. This work consists of three parts to address the use of muons for subsurface characterization : 1) assess the use of muon scattering for estimating density differences of common rock types, 2 ) using muon flux to detect a void in rock, 3) measure muon direction by designing a new detector. Results from this project lay the groundwork for future directions in this field. Low-density objects can be detected by muons even when enclosed in high-density material like lead, and even small changes in density (e.g. changes due to fracturing of material) can be detected. Rock density has a linear relationship with muon scattering density per rock volume when this ratio is greater than 0.10 . Limitations on using muon scattering to assess density changes among common rock types have been identified. However, other analysis methods may show improved results for these relatively low density materials. Simulations show that muons can be used to image void space (e.g. tunnels) within rock but experimental results have been ambiguous. Improvements are suggested to improve imaging voids such as tunnels through rocks. Finally, a muon detector has been designed and tested to measure muon direction, which will improve signal-to-noise ratio and help address fundamental questions about the source of upgoing muons .

  4. Single cell genomics of subsurface microorganisms

    NASA Astrophysics Data System (ADS)

    Stepanauskas, R.; Onstott, T. C.; Lau, C.; Kieft, T. L.; Woyke, T.; Rinke, C.; Sczyrba, A.; van Heerden, E.

    2012-12-01

    Recent studies have revealed unexpected abundance and diversity of microorganisms in terrestrial and marine subsurface, providing new perspectives over their biogeochemical significance, evolution, and the limits of life. The now commonly used research tools, such as metagenomics and PCR-based gene surveys enabled cultivation-unbiased analysis of genes encoded by natural microbial communities. However, these methods seldom provide direct evidence for how the discovered genes are organized inside genomes and from which organisms do they come from. Here we evaluated the feasibility of an alternative, single cell genomics approach, in the analysis of subsurface microbial community composition, metabolic potential and microevolution at the Sanford Underground Research Facility (SURF), South Dakota, and the Witwaterstrand Basin, South Africa. We successfully recovered genomic DNA from individual microbial cells from multiple locations, including ultra-deep (down to 3,500 m) and low-biomass (down to 10^3 cells mL^-1) fracture water. The obtained single amplified genomes (SAGs) from SURF contained multiple representatives of the candidate divisions OP3, OP11, OD1 and uncharacterized archaea. By sequencing eight of these SAGs, we obtained the first genome content information for these phylum-level lineages that do not contain a single cultured representative. The Witwaterstrand samples were collected from deep fractures, biogeochemical dating of which suggests isolation from tens of thousands to tens of millions of years. Thus, these fractures may be viewed as "underground Galapagos", a natural, long-term experiment of microbial evolution within well-defined temporal and spatial boundaries. We are analyzing multiple SAGs from these environments, which will provide detailed information about adaptations to life in deep subsurface, mutation rates, selective pressures and gene flux within and across microbial populations.

  5. Tree Distributions, Subsurface Characteristics and Nitrogen Cycling

    NASA Astrophysics Data System (ADS)

    Brunner, L.; Wallace, M. C.; Brush, G.

    2014-12-01

    This study examines the connection between vegetation and geologic, soil and hydrologic subsurface characteristics of a natural deciduous forest in Oregon Ridge Park, located in the Piedmont physiographic province in Maryland, USA. A preliminary study showed the relationship between nitrogen cycling and four different species occurring on a coarse grained schist and a fine grained schist. Mineralization values for Liriodendon tulipifera were positive on the coarser grained substrate and negative on the fine grained substrate. Nitrification values were positive on both substrates. Mineralization and nitrification values were both positive for Quercus prinus on both the coarse and fine substrates. Mineralization values for Acer rubrum were negative on the coarse substrate and positive on the finer substrate, while mineralization for Quercus rubra was negative on the coarse substrate and positive on the fine schist. Nitrification was positive for Q. rubra on the coarse schist and both positive and negative on the fine schist. Resistivity analyses were performed in collaboration with the Wyoming Center for Environmental Hydrology and Geophysics (WyCEHG) along two perpendicular transects at the study site. This analysis provides indirect information on subsurface conductivity, with low resistivity being interpreted as subsurface water or clay. One transect crossed a valley with a first-order stream in the center, while the second transect was taken along the break and slope of the hillslope. All trees were identified and diameter at breast height (DBH) measured in sixty-three randomly located plots along both transects. A principle components analysis of all tree data showed four associations of species. The plots were labelled as to association. The position of the associations along the transects show a relationship between wet, dry and mesic associations with differences in transect resistivity.

  6. Subsurface Flow in Gravel River Bars

    NASA Astrophysics Data System (ADS)

    Bray, E. N.; Dunne, T.

    2014-12-01

    The geomorphic and hydraulic characteristics of gravel bars control the direction, magnitude and spatial patterns of infiltration and exfiltration between rivers and their immediate subsurface environments. Bed undulation, water-surface gradient, alluvial depth, and the spatial variation of hydraulic conductivity (both deterministic trends and stochastic variability) affect the hydrologically-driven groundwater-surface water exchange. In this paper, we use a set of field measurements of morphological and hydrological characteristics along two reaches of the San Joaquin River, California to motivate a systematic analysis of the factors that affect paths and residence times of flow through gravel bars under an observed range of streamflow values. In the field investigation, it is shown that asymmetry of bar morphology is a first-order control on the extent and magnitude of infiltration, which is often represented to produce approximately equal areas of infiltration and seepage under the assumption of sinusoidal bedforms. Infiltration over the length of a bar is shown to be greater at low flow than at high flow because of the effect of water-surface gradient. Hydraulic conductivity (ksat) varies by orders of magnitude and systematic downstream coarsening arises related to the process of bar evolution. The lowest values of ksat were observed where the difference between the topographic gradient and the water-surface gradient is at a maximum and thus where the infiltration would be greatest into a uniform bar of homogeneous gravel. Morphology and fine sediment accumulation in recharge zones exert an important control over the mechanisms driving subsurface fluid exchange. Simulations from a numerical groundwater flow model that isolate the signatures of morphology and streambed sediment patterns on subsurface flow corroborate our interpretation that the infiltration patterns and rates are primarily controlled by bed morphology, with ksat playing a secondary role.

  7. Shallow Subsurface Structures of Volcanic Fissures

    NASA Astrophysics Data System (ADS)

    Parcheta, C. E.; Nash, J.; Mitchell, K. L.; Parness, A.

    2015-12-01

    Volcanic fissure vents are a difficult geologic feature to quantify. They are often too thin to document in detail with seismology or remote geophysical methods. Additionally, lava flows, lava drain back, or collapsed rampart blocks typically conceal a fissure's surface expression. For exposed fissures, quantifying the surface (let along sub0surface) geometric expression can become an overwhelming and time-consuming task given the non-uniform distribution of wall irregularities, drain back textures, and the larger scale sinuosity of the whole fissure system. We developed (and previously presented) VolcanoBot to acquire robust characteristic data of fissure geometries by going inside accessible fissures after an eruption ends and the fissure cools off to <50 C. Data from VolcanoBot documents the fissure conduit geometry with a near-IR structured light sensor, and reproduces the 3d structures to cm-scale accuracy. Here we present a comparison of shallow subsurface structures (<30 m depth) within the Mauna Ulu fissure system and their counterpart features at the vent-to-ground-surface interface. While we have not mapped enough length of the fissure to document sinuosity at depth, we see a self-similar pattern of irregularities on the fissure walls throughout the entire shallow subsurface, implying a fracture mechanical origin similar to faults. These irregularities are, on average, 1 m across and protrude 30 cm into the drained fissure. This is significantly larger than the 10% wall roughness addressed in the engineering literature on fluid dynamics, and implies that magma fluid dynamics during fissure eruptions are probably not as passive nor as simple as previously thought. In some locations, it is possible to match piercing points across the fissure walls, where the dike broke the wall rock in order to propagate upwards, yet in other locations there are erosional cavities, again, implying complex fluid dynamics in the shallow sub-surface during fissure eruptions.

  8. Noble gas fractionation during subsurface gas migration

    NASA Astrophysics Data System (ADS)

    Sathaye, Kiran J.; Larson, Toti E.; Hesse, Marc A.

    2016-09-01

    Environmental monitoring of shale gas production and geological carbon dioxide (CO2) storage requires identification of subsurface gas sources. Noble gases provide a powerful tool to distinguish different sources if the modifications of the gas composition during transport can be accounted for. Despite the recognition of compositional changes due to gas migration in the subsurface, the interpretation of geochemical data relies largely on zero-dimensional mixing and fractionation models. Here we present two-phase flow column experiments that demonstrate these changes. Water containing a dissolved noble gas is displaced by gas comprised of CO2 and argon. We observe a characteristic pattern of initial co-enrichment of noble gases from both phases in banks at the gas front, followed by a depletion of the dissolved noble gas. The enrichment of the co-injected noble gas is due to the dissolution of the more soluble major gas component, while the enrichment of the dissolved noble gas is due to stripping from the groundwater. These processes amount to chromatographic separations that occur during two-phase flow and can be predicted by the theory of gas injection. This theory provides a mechanistic basis for noble gas fractionation during gas migration and improves our ability to identify subsurface gas sources after post-genetic modification. Finally, we show that compositional changes due to two-phase flow can qualitatively explain the spatial compositional trends observed within the Bravo Dome natural CO2 reservoir and some regional compositional trends observed in drinking water wells overlying the Marcellus and Barnett shale regions. In both cases, only the migration of a gas with constant source composition is required, rather than multi-stage mixing and fractionation models previously proposed.

  9. Parallel heater system for subsurface formations

    DOEpatents

    Harris, Christopher Kelvin [Houston, TX; Karanikas, John Michael [Houston, TX; Nguyen, Scott Vinh [Houston, TX

    2011-10-25

    A heating system for a subsurface formation is disclosed. The system includes a plurality of substantially horizontally oriented or inclined heater sections located in a hydrocarbon containing layer in the formation. At least a portion of two of the heater sections are substantially parallel to each other. The ends of at least two of the heater sections in the layer are electrically coupled to a substantially horizontal, or inclined, electrical conductor oriented substantially perpendicular to the ends of the at least two heater sections.

  10. Physiologically anaerobic microorganisms of the deep subsurface

    SciTech Connect

    Stevens, S.E. Jr.; Chung, K.T.

    1991-06-01

    This study seeks to determine numbers, diversity, and morphology of anaerobic microorganisms in 15 samples of subsurface material from the Idaho National Engineering Laboratory, in 18 samples from the Hanford Reservation and in 1 rock sample from the Nevada Test Site; set up long term experiments on the chemical activities of anaerobic microorganisms based on these same samples; work to improve methods for the micro-scale determination of in situ anaerobic microbial activity;and to begin to isolate anaerobes from these samples into axenic culture with identification of the axenic isolates.

  11. Surface modification by subsurface pressure induced diffusion

    NASA Astrophysics Data System (ADS)

    Zimmermann, Claus G.

    2012-01-01

    Polycrystalline Ag, covered with a nm thin siloxane layer, was irradiated with ultraviolet light in vacuum at 500 K. Ag particles of different aspect ratios, 50-1000 nm in size, formed on the surface, including a small fraction of nanorods. Pressurized water vapor bubbles are created in the subsurface region by hydrogen radicals photo-chemically released by the siloxane layer. They provide the driving force for a diffusive material flux along grain boundaries to the surface. This mechanism was modeled and found to agree with the experimental timescale: approximately 300 h are required for a 1000 nm particle to form.

  12. Airborne Electromagnetic Mapping of Subsurface Permafrost

    NASA Astrophysics Data System (ADS)

    Abraham, J. D.; Minsley, B. J.; Cannia, J. C.; Smith, B. D.; Walvoord, M. A.; Voss, C. I.; Jorgenson, T. T.; Wylie, B. K.; Anderson, L.

    2011-12-01

    Concerns over the impacts of climate change have recently energized research on the potential impacts thawing permafrost may have on groundwater flow, infrastructure, forest health, ecosystems, energy production, CO2 release, and contaminant transport. There is typically little knowledge about subsurface permafrost distributions, such as thickness and where groundwater-surface-water connections may occur through taliks. In June of 2010, the U.S. Geological Survey undertook an airborne electromagnetic (AEM) survey in the area of Fort Yukon, Alaska in order to map the 3-D distribution of permafrost and provide information for the development of groundwater models within the Yukon River Basin. Prior to the development of these models, information on areas of groundwater-surface water interaction was extremely limited. Lithology determined from a borehole drilled in Fort Yukon in 1994 agrees well with the resistivity depth sections inferred from the airborne survey. In addition to lithology, there a thermal imprint appears on the subsurface resistivity values. In the upper 20-50 m, the sections show continuous areas of high electrical resistivity, consistent with alluvial gravel deposits that are likely frozen. At depth, unfrozen gravel deposits have intermediate-to-high resistivity; frozen silts have intermediate resistivity; and unfrozen silts have low resistivity. Under the Yukon River and lakes where the subsurface is not frozen, zones of moderate resistivity intermix with areas of low resistivity. The areas of loess hills on the margins of the Yukon Flats have very-high electrical resistivity, indicating higher ice content, and are associated with the some of the greatest thickness of permafrost in the survey area. This work provides the first look into the 3-D distribution of permafrost in the areas around Fort Yukon and is a demonstration of the application of AEM to permafrost mapping. The AEM survey provides unprecedented 3-D images of subsurface electrical

  13. 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.

  14. Microbiological Transformations of Radionuclides in the Subsurface

    SciTech Connect

    Marshall, Matthew J.; Beliaev, Alex S.; Fredrickson, Jim K.

    2010-01-04

    Microorganisms are ubiquitous in subsurface environments although their populations sizes and metabolic activities can vary considerably depending on energy and nutrient inputs. As a result of their metabolic activities and the chemical properties of their cell surfaces and the exopolymers they produce, microorganisms can directly or indirectly facilitate the biotransformation of radionuclides, thus altering their solubility and overall fate and transport in the environment. Although biosorption to cell surfaces and exopolymers can be an important factor modifying the solubility of some radionuclides under specific conditions, oxidation state is often considered the single most important factor controlling their speciation and, therefore, environmental behavior.

  15. Instrumented Moles for Planetary Subsurface Regolith Studies

    NASA Astrophysics Data System (ADS)

    Richter, L. O.; Coste, P. A.; Grzesik, A.; Knollenberg, J.; Magnani, P.; Nadalini, R.; Re, E.; Romstedt, J.; Sohl, F.; Spohn, T.

    2006-12-01

    Soil-like materials, or regolith, on solar system objects provide a record of physical and/or chemical weathering processes on the object in question and as such possess significant scientific relevance for study by landed planetary missions. In the case of Mars, a complex interplay has been at work between impact gardening, aeolian as well as possibly fluvial processes. This resulted in regolith that is texturally as well as compositionally layered as hinted at by results from the Mars Exploration Rover (MER) missions which are capable of accessing shallow subsurface soils by wheel trenching. Significant subsurface soil access on Mars, i.e. to depths of a meter or more, remains to be accomplished on future missions. This has been one of the objectives of the unsuccessful Beagle 2 landed element of the ESA Mars Express mission having been equipped with the Planetary Underground Tool (PLUTO) subsurface soil sampling Mole system capable of self-penetration into regolith due to an internal electro-mechanical hammering mechanism. This lightweight device of less than 900 g mass was designed to repeatedly obtain and deliver to the lander regolith samples from depths down to 2 m which would have been analysed for organic matter and, specifically, organic carbon from potential extinct microbial activity. With funding from the ESA technology programme, an evolved Mole system - the Instrumented Mole System (IMS) - has now been developed to a readiness level of TRL 6. The IMS is to serve as a carrier for in situ instruments for measurements in planetary subsurface soils. This could complement or even eliminate the need to recover samples to the surface. The Engineering Model hardware having been developed within this effort is designed for accommodating a geophysical instrument package (Heat Flow and Physical Properties Package, HP3) that would be capable of measuring regolith physical properties and planetary heat flow. The chosen design encompasses a two-body Mole

  16. Low temperature monitoring system for subsurface barriers

    SciTech Connect

    Vinegar, Harold J.; McKinzie, II. Billy John

    2009-08-18

    A system for monitoring temperature of a subsurface low temperature zone is described. The system includes a plurality of freeze wells configured to form the low temperature zone, one or more lasers, and a fiber optic cable coupled to at least one laser. A portion of the fiber optic cable is positioned in at least one freeze well. At least one laser is configured to transmit light pulses into a first end of the fiber optic cable. An analyzer is coupled to the fiber optic cable. The analyzer is configured to receive return signals from the light pulses.

  17. GEOSSAV: a simulation tool for subsurface applications

    NASA Astrophysics Data System (ADS)

    Regli, Christian; Rosenthaler, Lukas; Huggenberger, Peter

    2004-04-01

    Geostatistical Environment fOr Subsurface Simulation And Visualization (GEOSSAV) is a tool for the integration of hard and soft data into stochastic simulation and visualization of distributions of geological structures and hydrogeological properties in the subsurface. GEOSSAV, as an interface to selected geostatistical modules (bicalib, gamv, vargplt, and sisim) from the Geostatistical Software LIBrary, GSLIB (GSLIB: Geostatistical Software Library and User's Guide, 2nd Edition, Oxford University Press, Oxford, 1998, 369pp), can be used for data analysis, variogram computation of regularly or irregularly spaced data, and sequential indicator simulation of subsurface heterogeneities. Sequential indicator simulation, based on various kriging techniques (simple, ordinary, and Bayesian), is suitable for the simulation of continuous variables such as hydraulic conductivity of an aquifer or chemical concentrations at a contaminated site, and categorical variables which indicate the presence or absence of a particular lithofacies. The software integration platform and development environment of GEOSSAV is Tool command language (Tcl) with its graphical user interface, Toolkit (Tk), and a number of Tcl/Tk extensions. The standard Open Graphics Library application programming interface is used for rendering three-dimensional (3D) data distributions and for slicing perpendicular to the main coordinate axis. Export options for finite-difference groundwater models allow either files that characterize single model layers (which are saved in ASCII matrix format) or files that characterize the complete 3D flow model setup for MODFLOW-based groundwater simulation systems (which are saved in block-centered flow package files (User's documentation for MODFLOW-96, an update to the US Geological Survey modular finite-difference ground-water flow model, Geological Survey Open-File Report 96-485, Reston, VA, 1996, 56pp)). GEOSSAV can be used whenever stochastic solutions are preferred

  18. Surface modification by subsurface pressure induced diffusion

    SciTech Connect

    Zimmermann, Claus G.

    2012-01-23

    Polycrystalline Ag, covered with a nm thin siloxane layer, was irradiated with ultraviolet light in vacuum at 500 K. Ag particles of different aspect ratios, 50-1000 nm in size, formed on the surface, including a small fraction of nanorods. Pressurized water vapor bubbles are created in the subsurface region by hydrogen radicals photo-chemically released by the siloxane layer. They provide the driving force for a diffusive material flux along grain boundaries to the surface. This mechanism was modeled and found to agree with the experimental timescale: approximately 300 h are required for a 1000 nm particle to form.

  19. Transport of subsurface bacteria in porous media

    SciTech Connect

    Bales, R.C.; Arnold, R.G.; Gerba, C.P.

    1995-02-01

    The primary objective of this study was to develop tools with which to measure the advective transport of microorganisms through porous media. These tools were then applied to investigate the sorptive properties of representative microorganisms that were selected at random from the DOE`s deep subsurface collection of bacterial, maintained at Florida State University. The transport screening procedure that arose from this study was also used to investigate biological factors that affect the transport/sorption of biocolloids during their movement through porous media with the bulk advective flow.

  20. A new high-resolution electromagnetic method for subsurface imaging

    NASA Astrophysics Data System (ADS)

    Feng, Wanjie

    For most electromagnetic (EM) geophysical systems, the contamination of primary fields on secondary fields ultimately limits the capability of the controlled-source EM methods. Null coupling techniques were proposed to solve this problem. However, the small orientation errors in the null coupling systems greatly restrict the applications of these systems. Another problem encountered by most EM systems is the surface interference and geologic noise, which sometimes make the geophysical survey impossible to carry out. In order to solve these problems, the alternating target antenna coupling (ATAC) method was introduced, which greatly removed the influence of the primary field and reduced the surface interference. But this system has limitations on the maximum transmitter moment that can be used. The differential target antenna coupling (DTAC) method was proposed to allow much larger transmitter moments and at the same time maintain the advantages of the ATAC method. In this dissertation, first, the theoretical DTAC calculations were derived mathematically using Born and Wolf's complex magnetic vector. 1D layered and 2D blocked earth models were used to demonstrate that the DTAC method has no responses for 1D and 2D structures. Analytical studies of the plate model influenced by conductive and resistive backgrounds were presented to explain the physical phenomenology behind the DTAC method, which is the magnetic fields of the subsurface targets are required to be frequency dependent. Then, the advantages of the DTAC method, e.g., high-resolution, reducing the geologic noise and insensitive to surface interference, were analyzed using surface and subsurface numerical examples in the EMGIMA software. Next, the theoretical advantages, such as high resolution and insensitive to surface interference, were verified by designing and developing a low-power (moment of 50 Am 2) vertical-array DTAC system and testing it on controlled targets and scaled target coils. At last, a

  1. Atomic-Scale Chemical, Physical and Electronic Properties of the Subsurface Hydride of Palladium

    SciTech Connect

    Weiss, Paul

    2014-01-20

    We employed low-temperature, extreme-high vacuum scanning tunneling microscopy (STM) to investigate the roles of subsurface hydride (H) and deuteride (D) in the surface reconstruction and surface reactivity of Pd{110}. Specifically, we gained the ability to tailor the surface structure of Pd{110} both by preparation method and by deposition of deuterium from the gas phase. We observed thiophene at low coverage on Pd{110} to determine its adsorption orientation and electronic structure through scanning tunneling spectroscopy (STS) – namely, conductance spectroscopy and differential conductance imaging. We developed the methods necessary to coadsorb D adatoms with thiophene molecules, and to induce the reaction of individual molecules with predefined subsurface H or D features. In the case of Pd{110}, we found a much more pronounced effect from subsurface D, as it is influenced by the surface directionality. These experiments facilitate an understanding of the role of surface and subsurface H and D in heterogeneous catalytic processes, specifically in the hydrodesulfuization (HDS) of thiophene, an important and ubiquitous component found to be detrimental to petroleum refining.

  2. Long-term evolution of anthropogenic heat fluxes into a subsurface urban heat island.

    PubMed

    Menberg, Kathrin; Blum, Philipp; Schaffitel, Axel; Bayer, Peter

    2013-09-03

    Anthropogenic alterations in urban areas influence the thermal environment causing elevated atmospheric and subsurface temperatures. The subsurface urban heat island effect is observed in several cities. Often shallow urban aquifers exist with thermal anomalies that spread laterally and vertically, resulting in the long-term accumulation of heat. In this study, we develop an analytical heat flux model to investigate possible drivers such as increased ground surface temperatures (GSTs) at artificial surfaces and heat losses from basements of buildings, sewage systems, subsurface district heating networks, and reinjection of thermal wastewater. By modeling the anthropogenic heat flux into the subsurface of the city of Karlsruhe, Germany, in 1977 and 2011, we evaluate long-term trends in the heat flux processes. It revealed that elevated GST and heat loss from basements are dominant factors in the heat anomalies. The average total urban heat flux into the shallow aquifer in Karlsruhe was found to be ∼759 ± 89 mW/m(2) in 1977 and 828 ± 143 mW/m(2) in 2011, which represents an annual energy gain of around 1.0 × 10(15) J. However, the amount of thermal energy originating from the individual heat flux processes has changed significantly over the past three decades.

  3. The effect of streambed topography on surface-subsurface water exchange in mountain catchments

    USGS Publications Warehouse

    Harvey, Judson W.; Bencala, Kenneth E.

    1993-01-01

    A numerical hydrological simulation suggested that water exchange between stream channels and adjacent aquifers is enhanced by convexities and concavities in streambed topography. At St. Kevin Gulch, an effluent stream in the Rocky Mountains of Colorado, subsurface hydraulic gradients and movement of ionic tracers indicated that stream water was locally recharged into well-defined flow paths through the alluvium. Stream water-filled flow paths in the alluvium (referred to as substream flow paths) returned to the stream a short distance downstream (1 to 10 m). Recharge to the substream flow paths occurred where stream water slope increased, at the transition from pools (<1%) to steeper channel units (5–20%). Return of substream flow paths to the stream occurred where stream water slope decreased, at the transition from steeper channel units to pools. A net water flux calculation is typically used to characterize water and solute fluxes between surface and subsurface zones of catchments. Along our study reach at St. Kevin Gulch the net inflow of water from subsurface to stream (1.6 mL s−1 m−1) underestimated the gross inflow (2.7 mL s−1 m−1) by 40%. The influence of streambed topography is to enhance hydrological fluxes between stream water and subsurface zones and to prolong water-sediment contact times; these effects could have important consequences for solute transport, retention, and transformation in catchments.

  4. Impact of deforestation on subsurface temperature profiles: implications for the borehole paleoclimate record

    NASA Astrophysics Data System (ADS)

    MacDougall, Andrew H.; Beltrami, Hugo

    2017-07-01

    Subsurface temperature profiles measured in boreholes are one of the important archives of paleoclimate data for reconstructing the climate of the past 2000 years. Subsurface temperatures are a function of past ground surface temperatures (GST), however GSTs are influenced both by changes in land-use and changes in regional climate. Thus the history of deforestation at borehole sampling locations represents a potential uncertainty in the reconstructed temperature history at the site. Here a fully coupled Earth system model is used estimate the magnitude of the subsurface temperature anomaly from deforestation events from a global perspective. The model simulations suggest that warming of the ground surface is the dominant response to deforestation, consistent with the limited field data that exist. The magnitude of the temperature anomaly varies by environment with a global average anomaly of 0.85 °C with a range of -0.48 °C to 1.78 °C. The warming originates from a reduction in the efficiency of turbulent energy flux to the atmosphere overcompensating an increase in albedo. Overall our simulations suggest that deforestation has a large impact on subsurface temperatures for centuries following deforestation and thus GST reconstructions should take into account previous deforestation events.

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

    NASA Astrophysics Data System (ADS)

    Yang, S.; Zhong, L.; Li, G.

    2016-12-01

    Aqueous colloidal silica suspensions as non-Newtonian fluids have been reported as carriers for remedial amendment delivery in subsurface. The knowledge of the rheological behavior of the silica suspensions is essential for the field injection and subsurface application. This contribution is focused on the rheological characteristics of colloidal silica suspensions under various environmental conditions relevant to amendment delivery for subsurface remediation. We systemically studied the influence of silica particle concentration, ionic strength, pH, aging, amendment type and concentration, and subsurface sediment on the rheological behavior of the suspensions. Results indicated the suspensions maintained shear thinning in a number of varieties. Higher colloidal suspensions concentration raised the absolute suspensions viscosity and increased the degree of shear thinning. Addition of salts (e.g., Na+ and K+) to increase the solution ionic strength also increased the viscosity of suspensions and the degree of shear thinning. The silica suspensions exhibited controllable viscosity at acidic and alkaline pH. Meanwhile, the viscosity of suspensions increased with aging and eventually became gels under favorable conditions. The gelation rate is related to silica particle concentration, ionic strength and addition of sediments.

  6. Characterization of surface/subsurface damage for ceramics with nanoindentation method

    NASA Astrophysics Data System (ADS)

    Bao, Yumei; Chai, Guozhong; Gu, Shengting

    2010-08-01

    Ceramics are increasingly used in the fields of aerospace, communication, mechanical and modern biomedical engineering. With high hardness, strength and abrasive resistance, the machined ceramic components are most likely to contain surface/subsurface damages, influencing strongly the performance and reliability of ceramic components. Nanoindentation test is an advanced technology in measuring the elastic modulus and hardness of the materials in micro-nano scale based on Oliver-Phar's equation. Nanoindentation has been employed extensively to characterize the mechanical properties of a wide range of materials including ceramics. To characterize the surface/subsurface damage in ceramics, a degraded elastic modulus based damage variable is defined to describe the damage induced property degradation of the materials based on the traditional Kachanov continuum damage mechanics (CDM) framework. A simple characterization method for surface/subsurface damage is realized based on nanoindentation test. The alumina bulk samples are chosen to study the surface/subsurface indentation induced damage by nanoindentaiton. The elastic modulus under various indenting loads is measured with Conical and Berkovich tip. The variation of the elastic modulus and indentation induced damage with load and displacement are analyzed in detail. Experimental results show that the proposed method is feasible and satisfactory.

  7. EM Task 13 - Cone Penetrometer for Subsurface Heavy Metals Detection

    SciTech Connect

    Ames A. Grisanti; Charlene R. Crocker

    1998-11-01

    Surface and subsurface contamination of soils by heavy metals, including Pb, Cr, Cu, Zn, and Cd has become an area of concern for many industrial and government organizations (1) Conventional sampling and analysis techniques for soil provide a high degree of sensitivity and selectivity for individual analytes. However, obtaining a representative sampling and analysis from a particular site using conventional techniques is time consuming and costly (2) Additionally, conventional methods are difficult to implement in the field for in situ and/or real-time applications. Therefore, there is a need for characterization and monitoring techniques for heavy metals in soils that allow cost-effective, rapid, in situ measurements. The overall objectives of this project are to evaluate potential calibration techniques for the laser-induced breakdown spectroscopy (LIBS)-CPT instrument, to provide a preliminary evaluation of the LIBS instrument calibration using samples obtained from the field and to provide technical support to field demonstration of the LIBS-CPT instrument at a DOE facility.

  8. STOMP Subsurface Transport Over Multiple Phases: User`s guide

    SciTech Connect

    White, M.D.; Oostrom, M.

    1997-10-01

    The U.S. Department of Energy, through the Office of Technology Development, has requested the demonstration of remediation technologies for the cleanup of volatile organic compounds and associated radionuclides within the soil and groundwater at arid sites. This demonstration program, called the VOC-Arid Soils Integrated Demonstration Program (Arid-ID), has been initially directed at a volume of unsaturated and saturated soil contaminated with carbon tetrachloride, on the Hanford Site near Richland, Washington. A principal subtask of the Arid-ID program involves the development of an integrated engineering simulator for evaluating the effectiveness and efficiency of various remediation technologies. The engineering simulator`s intended users include scientists and engineers who are investigating soil physics phenomena associated with remediation technologies. Principal design goals for the engineer simulator include broad applicability, verified algorithms, quality assurance controls, and validated simulations against laboratory and field-scale experiments. An important goal for the simulator development subtask involves the ability to scale laboratory and field-scale experiments to full-scale remediation technologies, and to transfer acquired technology to other arid sites. The STOMP (Subsurface Transport Over Multiple Phases) simulator has been developed by the Pacific Northwest National Laboratory for modeling remediation technologies. Information on the use, application, and theoretical basis of the STOMP simulator theory and discussions on the governing equations, constitutive relations, and numerical solution algorithms for the STOMP simulator.

  9. Fast 3D subsurface imaging with stepped-frequency GPR

    NASA Astrophysics Data System (ADS)

    Masarik, Matthew P.; Burns, Joseph; Thelen, Brian T.; Sutter, Lena

    2015-05-01

    This paper investigates an algorithm for forming 3D images of the subsurface using stepped-frequency GPR data. The algorithm is specifically designed for a handheld GPR and therefore accounts for the irregular sampling pattern in the data and the spatially-variant air-ground interface by estimating an effective "ground-plane" and then registering the data to the plane. The algorithm efficiently solves the 4th-order polynomial for the Snell reflection points using a fully vectorized iterative scheme. The forward operator is implemented efficiently using an accelerated nonuniform FFT (Greengard and Lee, 2004); the adjoint operator is implemented efficiently using an interpolation step coupled with an upsampled FFT. The imaging is done as a linearized version of the full inverse problem, which is regularized using a sparsity constraint to reduce sidelobes and therefore improve image localization. Applying an appropriate sparsity constraint, the algorithm is able to eliminate most the surrounding clutter and sidelobes, while still rendering valuable image properties such as shape and size. The algorithm is applied to simulated data, controlled experimental data (made available by Dr. Waymond Scott, Georgia Institute of Technology), and government-provided data with irregular sampling and air-ground interface.

  10. Crystal structure of laser-induced subsurface modifications in Si

    SciTech Connect

    Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.; Haberl, B.; Bradby, J. E.; Williams, J. S.; Huis in ’t Veld, A. J.

    2015-06-04

    Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this paper, we investigate the geometry and crystal structure of laser-induced subsurface modifications in monocrystalline silicon wafers. Finally, in addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si-iii/Si-xii occur as a result of the laser irradiation.

  11. Crystal structure of laser-induced subsurface modifications in Si

    DOE PAGES

    Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.; ...

    2015-06-04

    Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this paper, we investigate the geometry and crystalmore » structure of laser-induced subsurface modifications in monocrystalline silicon wafers. Finally, in addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si-iii/Si-xii occur as a result of the laser irradiation.« less

  12. High-resolution subsurface water-ice distributions on Mars.

    PubMed

    Bandfield, Joshua L

    2007-05-03

    Theoretical models indicate that water ice is stable in the shallow subsurface (depths of <1-2 m) of Mars at high latitudes. These models have been mainly supported by the observed presence of large concentrations of hydrogen detected by the Gamma Ray Spectrometer suite of instruments on the Mars Odyssey spacecraft. The models and measurements are consistent with a water-ice table that steadily increases in depth with decreasing latitude. More detailed modelling has predicted that the depth at which water ice is stable can be highly variable, owing to local surface heterogeneities such as rocks and slopes, and the thermal inertia of the ground cover. Measurements have, however, been limited to the footprint (several hundred kilometres) of the Gamma Ray Spectrometer suite, preventing the observations from documenting more detailed water-ice distributions. Here I show that by observing the seasonal temperature response of the martian surface with the Thermal Emission Imaging System on the Mars Odyssey spacecraft, it is possible to observe such heterogeneities at subkilometre scale. These observations show significant regional and local water-ice depth variability, and, in some cases, support distributions in the subsurface predicted by atmospheric exchange and vapour diffusion models. The presence of water ice where it follows the depth of stability under current climatic conditions implies an active martian water cycle that responds to orbit-driven climate cycles. Several regions also have apparent deviations from the theoretical stability level, indicating that additional factors influence the ice-table depth. The high-resolution measurements show that the depth to the water-ice table is highly variable within the potential Phoenix spacecraft landing ellipses, and is likely to be variable at scales that may be sampled by the spacecraft.

  13. Mass conservative BDF-discontinuous Galerkin/explicit finite volume schemes for coupling subsurface and overland flows

    NASA Astrophysics Data System (ADS)

    Sochala, P.; Ern, A.; Piperno, S.

    2009-05-01

    Robust and accurate schemes are designed to simulate the coupling between subsurface and overland flows. The coupling conditions at the interface enforce the continuity of both the normal flux and the pressure. Richards' equation governing the subsurface flow is discretized using a Backward Differentiation Formula and a symmetric interior penalty Discontinuous Galerkin method. The kinematic wave equation governing the overland flow is discretized using a Godunov scheme. Both schemes individually are mass conservative and can be used within single-step or multi-step coupling algorithms that ensure overall mass conservation owing to a specific design of the interface fluxes in the multi-step case. Numerical results are presented to illustrate the performances of the proposed algorithms.

  14. Subsurface Thermal Energy Storage for Improved Air Conditioning Efficiency

    DTIC Science & Technology

    2016-11-01

    EW-201013) Subsurface Thermal Energy Storage for Improved Air Conditioning Efficiency November 2016 This document has been cleared for public...December 2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER 10-C-0027-A Cost and Performance Report. Subsurface Thermal Energy Storage for Improved...distribution is unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT This project involved a field demonstration of subsurface thermal energy storage for

  15. Evaluation of Subsurface Engineered Barriers at Waste Sites

    DTIC Science & Technology

    1998-08-01

    Evaluation of Subsurface Engineered Barriers at Waste Sites United States Environmental Protection Agency Office of Solid Waste and Emergency...of Subsurface Engineered Barriers at Waste Sites 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER...1998 www.epa.gov clu-in.com EVALUATION OF SUBSURFACE ENGINEERED BARRIERS AT WASTE SITES i NOTICE This document was prepared for the U.S. Environmental

  16. The subsurface origin of microbial life on the Earth.

    PubMed

    Trevors, J T

    2002-10-01

    Life on Earth can be divided into life on the surface made possible by photosynthesis and subsurface life with chemical energy as the driving force. An understanding of both environments is central to our understanding of the origin of life, the search for novel microbial species in the subsurface and for extraterrestrial life or life signatures. In this manuscript, the surface and subsurface worlds are examined with a focus on the origin or assembly of bacterial life.

  17. Leisure, Government and Governance: A Swedish Perspective

    ERIC Educational Resources Information Center

    Lindstrom, Lisbeth

    2011-01-01

    The leisure sector has witnessed a tremendous expansion since 1960. The purpose of this article is to analyse the decisions and goals of Swedish government policy during the period 1962 to 2005. The empirical analysis covers government Propositions and governmental investigations. The fields covered are sports, culture, exercise, tourism and…

  18. Leisure, Government and Governance: A Swedish Perspective

    ERIC Educational Resources Information Center

    Lindstrom, Lisbeth

    2011-01-01

    The leisure sector has witnessed a tremendous expansion since 1960. The purpose of this article is to analyse the decisions and goals of Swedish government policy during the period 1962 to 2005. The empirical analysis covers government Propositions and governmental investigations. The fields covered are sports, culture, exercise, tourism and…

  19. Seasonal variations in the subsurface ultraviolet-B on an inshore Pacific coral reef ecosystem.

    PubMed

    Downs, Nathan J; Schouten, Peter W; Parisi, Alfio V

    2013-01-01

    Fringing coral reefs provide a unique opportunity to study shallow aquatic ecosystems. A fringing coral reef system located in close proximity to a developed region was considered in this study. In such an environment, the rate of decay of dissolved organic matter is high and the penetration of higher energy ultraviolet-B (UVB) extends a greater influence on species diversity, particularly upon shallow benthic communities. Results from a 9 month subsurface UVB exposure measurement campaign performed at a site located on the southern Queensland coast (Hervey Bay, 25°S) are presented in this research. For this, a novel dosimetric technique was utilized to measure long-term subsurface UVB exposures. The resultant data set includes exposure measurements made during the significant La Niña event of late 2010 which resulted in unprecedented high sea surface temperatures and severe flooding across eastern Australia, impacting upon the lagoon regions of the Great Barrier Reef and Queensland's southern estuaries, including the study site. The influence of season, diurnal tidal variation, cloud cover and solar zenith angle were analyzed over the campaign period. Mean minimum daylight water depth was found to be the most significant factor influencing subsurface UVB. © 2013 The American Society of Photobiology.

  20. Selective factors governing in vitro β-carotene bioaccessibility: negative influence of low filtration cutoffs and alterations by emulsifiers and food matrices.

    PubMed

    Corte-Real, Joana; Richling, Elke; Hoffmann, Lucien; Bohn, Torsten

    2014-12-01

    Because of their putative health benefits, the biological fate of carotenoids after digestion has been met with much interest, and ex vivo methods using carotenoid standards to study their digestion and further metabolism have been developed. In the absence of a complex food matrix, that is, when studying isolated carotenoids, protocol conditions of gastrointestinal digestion models have to be adjusted. In this investigation, we hypothesized that certain selected factors would significantly influence the bioaccessibility of β-carotene in vitro. The factors considered included (i) type of lipid matrix employed (milk, cream, or oil), (ii) presence/absence of emulsifiers (e.g. lecithin and taurocholate), (iii) addition of a gastric lipase, and (iv) final filtration (20 or 200 nm) of the digesta. Adding an emulsifier mixture (10 mg lecithin + 50 mg monoolein + 5 mg oleic acid) enhanced β-carotene bioaccessibility 3 times (P < 0.001), whereas additional taurocholate and the presence/absence of gastric lipase added before intestinal digestion had no significant effect. β-Carotene bioaccessibility was superior with oil than with milk (18.8% ± 0.7% and 6.1% ± 0.7%, respectively; P = 0.03), especially after filtration, thus suggesting incomplete micelle formation after addition of milk. Filtration through 20 nm filters reduced carotenoid concentration in the aqueous fraction (from 7.1% ± 0.2% to 5.5% ± 0.2% in samples digested with canola oil, P < 0.001), indicating that not all formed micelles compared in size with those normally formed in vivo. When studying carotenoid standards during in vitro digestion, care should be taken to separate mixed micelles by filtration, and the choice of emulsifier and matrix should be considered. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. The subsurface of Pluto from submillimetre observations

    NASA Astrophysics Data System (ADS)

    Greaves, J. S.; Whitelaw, A. C. M.; Bendo, G. J.

    2015-04-01

    Surface areas on Pluto change in brightness and colour, at optical to infrared wavelengths, over time-scales as short as years. The subsurface contains a reservoir of frozen volatiles, but little is known about it because Pluto is out of reach for cm-radar. Here we present a 0.85 mm wavelength light curve of the Pluto system, from archival data taken in 1997 August with the SCUBA (Submillimetre Common-User Bolometer Array) camera on the James Clerk Maxwell Telescope (JCMT). This wavelength probes for the first time to just below the skin depth of thermal changes over Pluto's day. The light curve differs significantly from counterparts in the mid- to far-infrared, in a longitude range that is optically dark on Pluto's surface. An estimate from Herschel of the 0.5 mm flux in 2012 is comparable to the mean 0.45 mm flux from SCUBA in 1997, suggesting that layers centimetres below the surface have not undergone any gross temperature change. The longitudes that are relatively submillimetre-faint could have a different emissivity, perhaps with a subsurface layer richer in nitrogen or methane ices than at the surface. The Radio Science Experiment (REX) instrument on New Horizons may be able to constrain physical properties deeper down, as it looks back on Pluto's nightside after the 2015 July flyby.

  2. Phylogenetic relationships among subsurface microorganisms. Progress report

    SciTech Connect

    Nierzwicki-Bauer, S.A.

    1991-12-31

    This project involves the development of group specific 16S ribosomal RNA-targeted oligonucleotide hybridization probes for the rapid detection of specific types of subsurface organisms (e.g., groups of microbes that share certain physiological traits). Major accomplishments for the period of 6/91 to 12/1/91 are described. Nine new probes have been synthesized on the basis of published 16S rRNA sequence data from the Ribosomal Database Project. We have initiated rapid screening of many of the subsurface microbial isolates obtained from the P24 borehole at the Savannah River Site. To date, we have screened approximately 50% of the isolates from P24. We have optimized our {und in situ} hybridization technique, and have developed a cell blot hybridization technique to screen 96 samples on a single blot. This is much faster than reading 96 individual slides. Preliminary experiments have been carried out which indicate specific nutrients can be used to amplify rRNA only in those organisms capable of metabolizing those nutrients. 1 tab., 2 figs.

  3. Calcium Carbonate Precipitation by Ureolytic Subsurface Bacteria

    SciTech Connect

    Fujita, Y.; Colwell, Frederick Scott; Smith, Robert William; Ferris, F. G.; Lawson, R. L.

    2000-10-01

    Coprecipitation in carbonate minerals offers a means of slowing the transport of divalent radionuclides and contaminant metals (e.g.,90Sr2+, UO2+, Co2+) in the subsurface. It may be possible to accelerate this process by stimulating the native microbial community to generate chemical conditions favoring carbonate precipitation. In a preliminary evaluation of this approach, we investigated the ability of ureolytic subsurface bacteria to produce alkaline conditions conducive to calcium carbonate precipitation. Groundwater samples from the Eastern Snake River Plain (ESRP) aquifer in Idaho were screened for urea-hydrolyzing microorganisms; three isolates were selected for further evaluation. Analysis of 16S rRNA gene sequences indicated that two of the ESRP isolates were of the genus Pseudomonas , and the other was a Variovorax sp. The specific urease activities of the ESRP isolates appeared to be similar to each other but less than that of Bacillus pasteurii , a known urease-positive organism. However, calcium carbonate was rapidly precipitated in all cultures that were supplied with urea and calcium, and X-ray diffraction analyses indicated that calcite was always the predominant carbonate polymorph produced. The correspondence between measured calcium concentrations and equilibrium predictions suggested that the rate of calcite precipitation was directly linked to the rate of urea hydrolysis. These results are promising with respect to the potential utility of this approach for in situ remediation and indicate that further evaluation of this approach under conditions more closely simulating environmental conditions is warranted.

  4. 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.

  5. Atmospheric energy for subsurface life on Mars?

    PubMed

    Weiss, B P; Yung, Y L; Nealson, K H

    2000-02-15

    The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H(2) and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H(2) and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H(2)O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life.

  6. Human utilization of subsurface extraterrestrial environments.

    PubMed

    Boston, P J; Frederick, R D; Welch, S M; Werker, J; Meyer, T R; Sprungman, B; Hildreth-Werker, V; Thompson, S L; Murphy, D L

    2003-06-01

    Caves have been used in the ancient past as shelter or habitat by many organisms (including humans). Since antiquity, humans have explored caves for the minerals they contain and sometimes for ceremonial purposes. Over the past century, caves have become the target of increasing exploration, scientific research, and recreation. The use of caves on extraterrestrial bodies for human habitation has been suggested by several investigators. Lunar lava tube bases received early attention because lava tubes were clearly visible in lunar images from the Apollo Era. More recently, Mars Observer Camera data has shown us clear evidence of large tubes visible in a number of volcanic regions on Mars. The budding field of cave geomicrobiology has direct application to questions about subsurface life on other planets. Caves contain many unusual organisms making their living from unlikely materials like manganese, iron, and sulfur. This makes caves and other subsurface habitats prime targets for astrobiological missions to Mars and possibly other bodies. We present the results of a completed Phase I and on-going Phase II NASA Institute for Advanced Concepts (NIAC) study that intensively examines the possibilities of using extraterrestrial caves as both a resource for human explorers and as a highly promising scientific target for both robotic and future human missions to Mars and beyond.

  7. Atmospheric energy for subsurface life on Mars?

    NASA Technical Reports Server (NTRS)

    Weiss, B. P.; Yung, Y. L.; Nealson, K. H.

    2000-01-01

    The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H(2) and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H(2) and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H(2)O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life.

  8. Atmospheric energy for subsurface life on Mars?

    NASA Technical Reports Server (NTRS)

    Weiss, B. P.; Yung, Y. L.; Nealson, K. H.

    2000-01-01

    The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H(2) and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H(2) and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H(2)O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life.

  9. Atmospheric energy for subsurface life on Mars?

    PubMed Central

    Weiss, Benjamin P.; Yung, Yuk L.; Nealson, Kenneth H.

    2000-01-01

    The location and density of biologically useful energy sources on Mars will limit the biomass, spatial distribution, and organism size of any biota. Subsurface Martian organisms could be supplied with a large energy flux from the oxidation of photochemically produced atmospheric H2 and CO diffusing into the regolith. However, surface abundance measurements of these gases demonstrate that no more than a few percent of this available flux is actually being consumed, suggesting that biological activity driven by atmospheric H2 and CO is limited in the top few hundred meters of the subsurface. This is significant because the available but unused energy is extremely large: for organisms at 30-m depth, it is 2,000 times previous estimates of hydrothermal and chemical weathering energy and far exceeds the energy derivable from other atmospheric gases. This also implies that the apparent scarcity of life on Mars is not attributable to lack of energy. Instead, the availability of liquid water may be a more important factor limiting biological activity because the photochemical energy flux can only penetrate to 100- to 1,000-m depth, where most H2O is probably frozen. Because both atmospheric and Viking lander soil data provide little evidence for biological activity, the detection of short-lived trace gases will probably be a better indicator of any extant Martian life. PMID:10660689

  10. Robotics subsurface mapping demonstration technology test plan

    SciTech Connect

    Griebenow, B.E.

    1991-06-01

    The Subsurface Disposal Area (SDA) at the Radioactive Waste Management Complex (RWMC) contains an estimated 2 million cubic feet of contaminated, hazardous, radioactive buried waste. The waste was received in cardboard boxes, steel drums plywood boxes, and as loose material. Possible leaching of the buried waste may have created mixed hazardous fill dirt, with an estimated volume of 6 million cubic feet. The Department of Energy has committed to clean up the SDA. Cleanup efforts will include characterizing and removing the waste. Waste characterization provides information on what, where, and how much waste is buried. This information will be used to determine how the waste will be removed and treated. Limited historical data of the waste buried within the SDA exist, but have not been verified and are believed to be incorrect or incomplete in many cases. There are two objectives to the Robotics Subsurface Mapping Demonstration. The first is to demonstrate the feasibility of using a remotely operated platform to perform characterization operations. In the demonstration, the Soldier Robot Interface Project (SRIP) platform will be equipped with multiple sensors to provide data for buried waste characterization and will be remotely controlled and tracked by the Ultrasonic Ranging and Data System (USRADS). The second objective of the demonstration is to characterize the waste in locations within the SDA, as specified by the Buried Waste Integrated Demonstration (BWID) Project.

  11. Modeling subsurface stormflow initiation in low-relief landscapes

    NASA Astrophysics Data System (ADS)

    Hopp, Luisa; Vaché, Kellie B.; Rhett Jackson, C.; McDonnell, Jeffrey J.

    2015-04-01

    Shallow lateral subsurface flow as a runoff generating mechanism at the hillslope scale has mostly been studied in steeper terrain with typical hillside angles of 10 - 45 degrees. These studies have shown that subsurface stormflow is often initiated at the interface between a permeable upper soil layer and a lower conductivity impeding layer, e.g. a B horizon or bedrock. Many studies have identified thresholds of event size and soil moisture states that need to be exceeded before subsurface stormflow is initiated. However, subsurface stormflow generation on low-relief hillslopes has been much less studied. Here we present a modeling study that investigates the initiation of subsurface stormflow on low-relief hillslopes in the Upper Coastal Plain of South Carolina, USA. Hillslopes in this region typically have slope angles of 2-5 degrees. Topsoils are sandy, underlain by a low-conductivity sandy clay loam Bt horizon. Subsurface stormflow has only been intercepted occasionally in a 120 m long trench, and often subsurface flow was not well correlated with stream signals, suggesting a disconnect between subsurface flow on the hillslopes and stream flow. We therefore used a hydrologic model to better understand which conditions promote the initiation of subsurface flow in this landscape, addressing following questions: Is there a threshold event size and soil moisture state for producing lateral subsurface flow? What role does the spatial pattern of depth to the impeding clay layer play for subsurface stormflow dynamics? We reproduced a section of a hillslope, for which high-resolution topographic data and depth to clay measurements were available, in the hydrologic model HYDRUS-3D. Soil hydraulic parameters were based on experimentally-derived data. The threshold analysis was first performed using hourly climate data records for 2009-2010 from the study site to drive the simulation. For this period also trench measurements of subsurface flow were available. In addition

  12. Subsurface Defect Detection in FRP Composites Using Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Halabe, U. B.; Vasudevan, A.; GangaRao, H. V. S.; Klinkhachorn, P.; Lonkar, G.

    2005-04-01

    This paper demonstrates the use of digital infrared thermography to detect subsurface defects such as debonds and delaminations in Fiber Reinforced Polymer (FRP) bridge decks. Simulated sub-surface debonds and delaminations were inserted between the wearing surface and the underlying FRP deck specimens. The infrared thermography technique was used to detect these embedded subsurface defects. The use of various cooling and heating methods, including solar radiation, was explored. Surface temperature-time curves were established for different types and sizes of subsurface defects.

  13. Surface and subsurface nitrate flow pathways on a watershed scale.

    PubMed

    Daughtry, C S; Gish, T J; Dulaney, W P; Walthall, C L; Kung, K J; McCarty, G W; Angier, J T; Buss, P

    2001-11-30

    Determining the interaction and impact of surface runoff and subsurface flow processes on the environment has been hindered by our inability to characterize subsurface soil structures on a watershed scale. Ground penetrating radar (GPR) data were collected and evaluated in determining subsurface hydrology at four small watersheds in Beltsville, MD. The watersheds have similar textures, organic matter contents, and yield distributions. Although the surface slope was greater on one of the watersheds, slope alone could not explain why it also had a nitrate runoff flux that was 18 times greater than the other three watersheds. Only with knowledge of the subsurface hydrology could the surface runoff differences be explained. The subsurface hydrology was developed by combining GPR and surface topography in a geographic information system. Discrete subsurface flow pathways were identified and confirmed with color infrared imagery, real-time soil moisture monitoring, and yield monitoring. The discrete subsurface flow patterns were also useful in understanding observed nitrate levels entering the riparian wetland and first order stream. This study demonstrated the impact that subsurface stratigraphy can have on water and nitrate (NO3-N) fluxes exiting agricultural lands, even when soil properties, yield distributions, and climate are similar. Reliable protocols for measuring subsurface fluxes of water and chemicals need to be developed.

  14. Effects of Atmospheric Conditions and the Land/Atmospheric Interface on Transport of Chemical Vapors from Subsurface Sources

    NASA Astrophysics Data System (ADS)

    Rice, A. K.; Smits, K. M.; Cihan, A.; Howington, S. E.; Illangasekare, T. H.

    2013-12-01

    Understanding the movement of chemical vapors and gas through variably saturated soil subjected to atmospheric thermal and mass flux boundary conditions at the land/atmospheric interface is important to many applications, including landmine detection, methane leakage during natural gas production from shale and CO2 leakage from deep geologic storage. New, advanced technologies exist to sense chemical signatures and gas leakage at the land/atmosphere interface, but interpretation of sensor signals remains a challenge. Chemical vapors are subject to numerous interactions while migrating through the soil environment, masking source conditions. The process governing movement of gases through porous media is often assumed to be Fickian diffusion through the air phase with minimal quantification of other processes, such as convective gas flow and temporal or spatial variation in soil moisture. Vapor migration is affected by atmospheric conditions (e.g. humidity, temperature, wind velocity), soil thermal and hydraulic properties and contaminant properties, all of which are physically and thermodynamically coupled. The complex coupling of two drastically different flow regimes in the subsurface and atmosphere is commonly ignored in modeling efforts, or simplifying assumptions are made to treat the systems as de-coupled. Experimental data under controlled laboratory settings are lacking to refine the theory for proper coupling and complex treatment of vapor migration through porous media in conversation with atmospheric flow and climate variations. Improving fundamental understanding and accurate quantification of these processes is not feasible in field settings due to lack of controlled initial and boundary conditions and inability to fully characterize the subsurface at all relevant scales. The goal of this work is to understand the influence of changes in atmospheric conditions to transport of vapors through variably saturated soil. We have developed a tank apparatus

  15. Microbial communities in the deep subsurface

    NASA Astrophysics Data System (ADS)

    Krumholz, Lee R.

    The diversity of microbial populations and microbial communities within the earth's subsurface is summarized in this review. Scientists are currently exploring the subsurface and addressing questions of microbial diversity, the interactions among microorganisms, and mechanisms for maintenance of subsurface microbial communities. Heterotrophic anaerobic microbial communities exist in relatively permeable sandstone or sandy sediments, located adjacent to organic-rich deposits. These microorganisms appear to be maintained by the consumption of organic compounds derived from adjacent deposits. Sources of organic material serving as electron donors include lignite-rich Eocene sediments beneath the Texas coastal plain, organic-rich Cretaceous shales from the southwestern US, as well as Cretaceous clays containing organic materials and fermentative bacteria from the Atlantic Coastal Plain. Additionally, highly diverse microbial communities occur in regions where a source of organic matter is not apparent but where igneous rock is present. Examples include the basalt-rich subsurface of the Columbia River valley and the granitic subsurface regions of Sweden and Canada. These subsurface microbial communities appear to be maintained by the action of lithotrophic bacteria growing on H2 that is chemically generated within the subsurface. Other deep-dwelling microbial communities exist within the deep sediments of oceans. These systems often rely on anaerobic metabolism and sulfate reduction. Microbial colonization extends to the depths below which high temperatures limit the ability of microbes to survive. Energy sources for the organisms living in the oceanic subsurface may originate as oceanic sedimentary deposits. In this review, each of these microbial communities is discussed in detail with specific reference to their energy sources, their observed growth patterns, and their diverse composition. This information is critical to develop further understanding of subsurface

  16. Implementing a new governance model.

    PubMed

    Stanley-Clarke, Nicky; Sanders, Jackie; Munford, Robyn

    2016-05-16

    Purpose - The purpose of this paper is to discuss the lessons learnt from the process of implementing a new model of governance within Living Well, a New Zealand statutory mental health agency. Design/methodology/approach - It presents the findings from an organisational case study that involved qualitative interviews, meeting observations and document analysis. Archetype theory provided the analytical framework for the research enabling an analysis of both the formal structures and informal value systems that influenced the implementation of the governance model. Findings - The research found that the move to a new governance model did not proceed as planned. It highlighted the importance of staff commitment, the complexity of adopting a new philosophical approach and the undue influence of key personalities as key determining factors in the implementation process. The findings suggest that planners and managers within statutory mental health agencies need to consider the implications of any proposed governance change on existing roles and relationships, thinking strategically about how to secure professional commitment to change. Practical implications - There are ongoing pressures within statutory mental health agencies to improve the efficiency and effectiveness of organisational structures and systems. This paper has implications for how planners and managers think about the process of implementing new governance models within the statutory mental health environment in order to increase the likelihood of sustaining and embedding new approaches to service delivery. Originality/value - The paper presents insights into the process of implementing new governance models within a statutory mental health agency in New Zealand that has relevance for other jurisdictions.

  17. Dispersion stability and electrokinetic properties of intrinsic plutonium colloids: implications for subsurface transport.

    PubMed

    Abdel-Fattah, Amr I; Zhou, Dongxu; Boukhalfa, Hakim; Tarimala, Sowmitri; Ware, S Doug; Keller, Arturo A

    2013-06-04

    Subsurface transport of plutonium (Pu) may be facilitated by the formation of intrinsic Pu colloids. While this colloid-facilitated transport is largely governed by the electrokinetic properties and dispersion stability (resistance to aggregation) of the colloids, reported experimental data is scarce. Here, we quantify the dependence of ζ-potential of intrinsic Pu(IV) colloids on pH and their aggregation rate on ionic strength. Results indicate an isoelectric point of pH 8.6 and a critical coagulation concentration of 0.1 M of 1:1 electrolyte at pH 11.4. The ζ-potential/pH dependence of the Pu(IV) colloids is similar to that of goethite and hematite colloids. Colloid interaction energy calculations using these values reveal an effective Hamaker constant of the intrinsic Pu(IV) colloids in water of 1.85 × 10(-19) J, corresponding to a relative permittivity of 6.21 and refractive index of 2.33, in agreement with first principles calculations. This relatively high Hamaker constant combined with the positive charge of Pu(IV) colloids under typical groundwater aquifer conditions led to two contradicting hypotheses: (a) the Pu(IV) colloids will exhibit significant aggregation and deposition, leading to a negligible subsurface transport or (b) the Pu(IV) colloids will associate with the relatively stable native groundwater colloids, leading to a considerable subsurface transport. Packed column transport experiments supported the second hypothesis.

  18. Pronounced subsurface cooling of North Atlantic waters off Northwest Africa during Dansgaard-Oeschger interstadials

    NASA Astrophysics Data System (ADS)

    Kim, Jung-Hyun; Romero, Oscar E.; Lohmann, Gerrit; Donner, Barbara; Laepple, Thomas; Haam, Eddie; Sinninghe Damsté, Jaap S.

    2012-07-01

    Millennial-scale Atlantic meridional overturning circulation (AMOC) variability has often been invoked to explain the Dansgaard-Oeschger (DO) events. However, the underlying causes responsible for millennial-scale AMOC variability are still debated. High-resolution U37K' and TEX86H temperature records for the last 50 kyr obtained from the tropical Northeast (NE) Atlantic (core GeoB7926-2, 20°13'N, 18°27'W, 2500 m water depth) show that distinctive DO-type subsurface (i.e. below the mixed layer: >20 m water depth) temperature oscillations occurred with amplitudes of up to 8 °C in the tropical NE Atlantic during Marine Isotope Stage 3 (MIS3). Statistical analyses reveal a positive relationship between the reconstructed substantial cooling of subsurface waters and prominent surface warming over Greenland during DO interstadials. General circulation model (GCM) simulations without external freshwater forcing, the mechanism often invoked in explaining DO events, demonstrate similar anti-phase correlations between AMOC and pronounced NE Atlantic subsurface temperatures under glacial climate conditions. Together with our paleoproxy dataset, this suggests that the vertical temperature structure and associated changes in AMOC were key elements governing DO events during the last glacial.

  19. Subsurface multiphase flow and multicomponent reactive transport modeling using high-performance computing

    NASA Astrophysics Data System (ADS)

    Hammond, Glenn; Lichtner, Peter; Lu, Chuan

    2007-07-01

    Numerical modeling is a critical tool to the U.S. Department of Energy for evaluating the environmental impact of remediation strategies for subsurface legacy waste sites. Unfortunately, the physical and chemical complexity of many sites overwhelms the capabilities of even most state of the art groundwater models. Of particular concern is the representation of highly-heterogeneous stratified rock/soil layers in the subsurface and the biological and geochemical interactions of chemical species within multiple fluid phases. There is clearly a need for higher-resolution modeling (i.e. increased spatial and temporal resolution) and increasingly mechanistic descriptions of subsurface physicochemical processes (i.e. increased chemical degrees of freedom). We present SciDAC-funded research being performed in furthering the development of PFLOTRAN, a parallel multiphase flow and multicomponent reactive transport model. Written in Fortran90, PFLOTRAN is founded upon PETSc data structures and solvers. We are employing PFLOTRAN to simulate uranium transport at the Hanford 300 Area, a contaminated site of major concern to the Department of Energy, the State of Washington, and other government agencies. By leveraging the billions of degrees of freedom available through high-performance computation using tens of thousands of processors, we can better characterize the release of uranium into groundwater and its subsequent transport to the Columbia River, and thereby better understand and evaluate the effectiveness of various proposed remediation strategies.

  20. Subsurface contamination focus area technical requirements. Volume II

    SciTech Connect

    Nickelson, D.; Nonte, J.; Richardson, J.

    1996-10-01

    This is our vision, a vision that replaces the ad hoc or {open_quotes}delphi{close_quotes} method which is to get a group of {open_quotes}experts{close_quotes} together and make decisions based upon opinion. To fulfill our vision for the Subsurface Contaminants Focus Area (SCFA), it is necessary to generate technical requirements or performance measures which are quantitative or measurable. Decisions can be supported if they are based upon requirements or performance measures which can be traced to the origin (documented) and are verifiable, i.e., prove that requirements are satisfied by inspection (show me), demonstration, analysis, monitoring, or test. The data from which these requirements are derived must also reflect the characteristics of individual landfills or plumes so that technologies that meet these requirements will necessarily work at specific sites. Other subjective factors, such as stakeholder concerns, do influence decisions. Using the requirements as a basic approach, the SCFA can depend upon objective criteria to help influence the areas of subjectivity, like the stakeholders. In the past, traceable requirements were not generated, probably because it seemed too difficult to do so. There are risks that the requirements approach will not be accepted because it is new and represents a departure from the historical paradigm.

  1. The DOE Subsurface (SubTER) Initiative: Revolutionizing Responsible use of the Subsurface for Energy Production and Storage

    NASA Astrophysics Data System (ADS)

    Hubbard, S. S.; Walck, M. C.; Blankenship, D.; Bonneville, A.; Bromhal, G. S.; Daley, T. M.; Pawar, R.; Polsky, Y.; Mattson, E.; Mellors, R. J.

    2015-12-01

    The subsurface supplies more than 80% of the U.S.'s total energy needs through geothermal and hydrocarbon strategies and also provides vast potential for safe storage of CO2 and disposal of nuclear waste. Responsible and efficient use of the subsurface poses many challenges, many of which require the capability to monitor and manipulate sub-surface stress, fractures, and fluid flow at all scales. Adaptive control of subsurface fractures and flow is a multi-disciplinary challenge that, if achieved, has the potential to transform all subsurface energy strategies. As part of the U.S. Department of Energy's SubTER (Subsurface Technology and Engineering Research development and demonstration) initiative, a multi-National Laboratory team is developing next-generation approaches that will allow for adaptive control of subsurface fractures and flow. SubTER has identified an initial suite of technical thrust areas to focus work, and has initiated a number of small projects. This presentation will describe early progress associated with the SubTER technical topic areas of wellbore integrity, subsurface stress and induced seismicity, permeability manipulation and new subsurface signals. It will also describe SubTER plans, and provide a venue to solicit suggestions and discuss potential partnerships associated with future research directions.

  2. Impact of Subsurface Heterogeneities on nano-Scale Zero Valent Iron Transport

    NASA Astrophysics Data System (ADS)

    Krol, M. M.; Sleep, B. E.; O'Carroll, D. M.

    2011-12-01

    Nano-scale zero valent iron (nZVI) has been applied as a remediation technology at sites contaminated with chlorinated compounds and heavy metals. Although laboratory studies have demonstrated high reactivity for the degradation of target contaminants, the success of nZVI in the field has been limited due to poor subsurface mobility. When injected into the subsurface, nZVI tends to aggregate and be retained by subsurface soils. As such nZVI suspensions need to be stabilized for increased mobility. However, even with stabilization, soil heterogeneities can still lead to non-uniform nZVI transport, resulting in poor distribution and consequently decreased degradation of target compounds. Understanding how nZVI transport can be affected by subsurface heterogeneities can aid in improving the technology. This can be done with the use of a numerical model which can simulate nZVI transport. In this study CompSim, a finite difference groundwater model, is used to simulate the movement of nZVI in a two-dimensional domain. CompSim has been shown in previous studies to accurately predict nZVI movement in the subsurface, and is used in this study to examine the impact of soil heterogeneity on nZVI transport. This work also explores the impact of different viscosities of the injected nZVI suspensions (corresponding to different stabilizing polymers) and injection rates on nZVI mobility. Analysis metrics include travel time, travel distance, and average nZVI concentrations. Improving our understanding of the influence of soil heterogeneity on nZVI transport will lead to improved field scale implementation and, potentially, to more effective remediation of contaminated sites.

  3. Methane emissions from MSW landfill with sandy soil covers under leachate recirculation and subsurface irrigation

    NASA Astrophysics Data System (ADS)

    Zhang, Houhu; He, Pinjing; Shao, Liming

    CH 4 emissions and leachate disposal are recognized as the two major concerns in municipal solid waste (MSW) landfills. Recently, leachate recirculation was attempted to accelerate land-filled waste biodegradation and thus enhanced landfill gas generation. Leachate irrigation was also conducted for volume reduction effectively. Nevertheless, the impacts of leachate recirculation and irrigation on landfill CH 4 emissions have not been previously reported. A field investigation of landfill CH 4 emissions was conducted on selected sandy soil cover with leachate recirculation and subsurface irrigation based on whole year around measurement. The average CH 4 fluxes were 311±903, 207±516, and 565±1460 CH 4 m -2 h -1 from site A without leachate recirculation and subsurface irrigation, lift B2 with leachate subsurface irrigation, and lift B1 with both leachate recirculation and subsurface irrigation, respectively. Both gas recovery and cover soil oxidation minimized CH 4 emissions efficiently, while the later might be more pronounced when the location was more than 5 m away from gas recovery well. After covered by additional clay soil layer, CH 4 fluxes dropped by approximately 35 times in the following three seasons compared to the previous three seasons in lift B2. The diurnal peaks of CH 4 fluxes occurred mostly followed with air or soil temperature in the daytimes. The measured CH 4 fluxes were much lower than those of documented data from the landfills, indicating that the influences of leachate recirculation and subsurface irrigation on landfill CH 4 emissions might be minimized with the help of a well-designed sandy soil cover. Landfill cover composed of two soil layers (clay soil underneath and sandy soil above) is suggested as a low-cost and effective alternative to minimize CH 4 emissions.

  4. Observation to Theory in Deep Subsurface Microbiology Research: Can We Piece It Together?

    NASA Astrophysics Data System (ADS)

    Colwell, F. S.; Thurber, A. R.

    2016-12-01

    Three decades of observations of microbes in deep environments have led to startling discoveries of life in the subsurface. Now, a few theoretical frameworks exist that help to define Stygian life. Temperature, redox gradients, productivity (e.g., in the overlying ocean), and microbial power requirements are thought to determine the distribution of microbes in the subsurface. Still, we struggle to comprehend the spatial and temporal spectra of Earth processes that define how deep microbe communities survive. Stommel diagrams, originally used to guide oceanographic sampling, may be useful in depicting the subsurface where microbial communities are impacted by co-occurring spatial and temporal phenomena that range across exponential scales. Spatially, the geological settings that influence the activity and distribution of microbes range from individual molecules or minerals all the way up to the planetary-scale where geological formations, occupying up to 105 km3, dictate the bio- and functional geography of microbial communities. Temporally, life in the subsurface may respond in time units familiar to humans (e.g., seconds to days) or to events that unfold over hundred millennial time periods. While surface community dynamics are underpinned by solar and lunar cycles, these cycles only fractionally dictate survival underground where phenomena like tectonic activity, isostatic rebound, and radioactive decay are plausible drivers of microbial life. Geological or planetary processes that occur on thousand or million year cycles could be uniquely important to microbial viability in the subsurface. Such an approach aims at a holistic comprehension of the interaction of Earth system dynamics with microbial ecology.

  5. Detection of microbial Life in the Subsurface

    NASA Astrophysics Data System (ADS)

    Stan-Lotter, H.; Fendrihan, S.; Dornmayr-Pfaffenhuemer, M.; Legat, A.; Gruber, C.; Weidler, G.; Gerbl, F.

    2007-08-01

    In recent years microbial communities were detected, which dwell in rocks, soil and caves deep below the surface of the Earth. This has led to a new view of the diversity of the terrestrial biosphere and of the physico-chemical boundaries for life. Two types of subterranean environments are Permo-Triassic salt sediments and thermal radioactive springs from igneous rocks in the Alps. Viable extremely halophilic archaea were isolated from ancient salt sediments which are estimated to be about 250 million years old (1). Chemotaxonomic and molecular characterization showed that they represent novel species, e. g. Halococcus salifodinae, Hcc. dombrowskiiand Halobacterium noricense. Simulation experiments with artificial halite suggested that these microorganisms probably survived while embedded in fluid inclusions. In the thermal springs, evidence for numerous novel microorganisms was found by 16S rDNA sequencing and probing for some metabolic genes; in addition, scanning electron microscopy of biofilms on the rock surfaces revealed great diversity of morphotypes (2). These communities appear to be active and growing, although their energy and carbon sources are entirely unknown. The characterization of subsurface inhabitants is of astrobiological relevance since extraterrestrial halite has been detected (3) and since microbial life on Mars, if existent, may have retreated into the subsurface. As a long-term goal, a thorough census of terrestrial microorganisms should be taken and their survival potential be determined in view of future missions for the search for extraterrestrial life, including planning precautions against possible forward contamination by space probes. (1) Fendrihan, S., Legat, A., Gruber, C., Pfaffenhuemer, M., Weidler, G., Gerbl, F., Stan-Lotter, H. (2006) Extremely halophilic archaea and the issue of long term microbial survival. Reviews in Environmental Science and Bio/technology 5, 1569-1605. (2) Weidler, G.W., Dornmayr-Pfaffenhuemer, M., Gerbl

  6. Subsurface data visualization in Virtual Reality

    NASA Astrophysics Data System (ADS)

    Krijnen, Robbert; Smelik, Ruben; Appleton, Rick; van Maanen, Peter-Paul

    2017-04-01

    Due to their increasing complexity and size, visualization of geological data is becoming more and more important. It enables detailed examining and reviewing of large volumes of geological data and it is often used as a communication tool for reporting and education to demonstrate the importance of the geology to policy makers. In the Netherlands two types of nation-wide geological models are available: 1) Layer-based models in which the subsurface is represented by a series of tops and bases of geological or hydrogeological units, and 2) Voxel models in which the subsurface is subdivided in a regular grid of voxels that can contain different properties per voxel. The Geological Survey of the Netherlands (GSN) provides an interactive web portal that delivers maps and vertical cross-sections of such layer-based and voxel models. From this portal you can download a 3D subsurface viewer that can visualize the voxel model data of an area of 20 × 25 km with 100 × 100 × 5 meter voxel resolution on a desktop computer. Virtual Reality (VR) technology enables us to enhance the visualization of this volumetric data in a more natural way as compared to a standard desktop, keyboard mouse setup. The use of VR for data visualization is not new but recent developments has made expensive hardware and complex setups unnecessary. The availability of consumer of-the-shelf VR hardware enabled us to create an new intuitive and low visualization tool. A VR viewer has been implemented using the HTC Vive head set and allows visualization and analysis of the GSN voxel model data with geological or hydrogeological units. The user can navigate freely around the voxel data (20 × 25 km) which is presented in a virtual room at a scale of 2 × 2 or 3 × 3 meters. To enable analysis, e.g. hydraulic conductivity, the user can select filters to remove specific hydrogeological units. The user can also use slicing to cut-off specific sections of the voxel data to get a closer look. This slicing

  7. ASSESSMENT OF THE SUBSURFACE FATE OF MONOETHANOLAMINE

    SciTech Connect

    James A. Sorensen; John R. Gallagher; Lori G. Kays

    2000-05-01

    Burial of amine reclaimer unit sludges and system filters has resulted in contamination of soil at the CanOxy Okotoks decommissioned sour gas-processing plant with amines, amine byproducts, and salts. A three-phase research program was devised to investigate the natural attenuation process that controls the subsurface transport and fate of these contaminants and to apply the results toward the development of a strategy for the remediation of this type of contamination in soils. Phase I experimental activities examined interactions between monoethanolamine (MEA) and sediment, the biodegradability of MEA in soils at various concentrations and temperatures, and the biodegradability of MEA sludge contamination in a soil slurry bioreactor. The transport and fate of MEA in the subsurface was found to be highly dependant on the nature of the release, particularly MEA concentration and conditions of the subsurface environment, i.e., pH, temperature, and oxygen availability. Pure compound biodegradation experiments in soil demonstrated rapid biodegradation of MEA under aerobic conditions and moderate temperatures (>6 C). Phase II landfarming activities confirmed that these contaminants are readily biodegradable in soil under ideal laboratory conditions, yet considerable toxicity was observed in the remaining material. Examination of water extracts from the treated soil suggested that the toxicity is water-soluble. Phase II activities led to the conclusion that landfarming is not the most desirable bioremediation technique; however, an engineered biopile with a leachate collection system could remove the remaining toxic fraction from the soil. Phase III was initiated to conduct field-based experimental activities to examine the optimized remediation technology. A pilot-scale engineered biopile was constructed at a decommissioned gas-sweetening facility in Okotoks, Alberta, Canada. On the basis of a review of the analytical and performance data generated from soil and

  8. Transformative environmental governance

    USGS Publications Warehouse

    Chaffin, Brian C.; Garmestani, Ahjond S.; Gunderson, Lance H.; Harm Benson, Melinda; Angeler, David G.; Arnold, Craig Anthony (Tony); Cosens, Barbara; Kundis Craig, Robin; Ruhl, J.B.; Allen, Craig R.

    2016-01-01

    Transformative governance is an approach to environmental governance that has the capacity to respond to, manage, and trigger regime shifts in coupled social-ecological systems (SESs) at multiple scales. The goal of transformative governance is to actively shift degraded SESs to alternative, more desirable, or more functional regimes by altering the structures and processes that define the system. Transformative governance is rooted in ecological theories to explain cross-scale dynamics in complex systems, as well as social theories of change, innovation, and technological transformation. Similar to adaptive governance, transformative governance involves a broad set of governance components, but requires additional capacity to foster new social-ecological regimes including increased risk tolerance, significant systemic investment, and restructured economies and power relations. Transformative governance has the potential to actively respond to regime shifts triggered by climate change, and thus future research should focus on identifying system drivers and leading indicators associated with social-ecological thresholds.

  9. "Once the government employs you, it forgets you": Health workers' and managers' perspectives on factors influencing working conditions for provision of maternal health care services in a rural district of Tanzania.

    PubMed

    Mkoka, Dickson Ally; Mahiti, Gladys Reuben; Kiwara, Angwara; Mwangu, Mughwira; Goicolea, Isabel; Hurtig, Anna-Karin

    2015-09-14

    In many developing countries, health workforce crisis is one of the predominant challenges affecting the health care systems' function of providing quality services, including maternal care. The challenge is related to how these countries establish conducive working conditions that attract and retain health workers into the health care sector and enable them to perform effectively and efficiently to improve health services particularly in rural settings. This study explored the perspectives of health workers and managers on factors influencing working conditions for providing maternal health care services in rural Tanzania. The researchers took a broad approach to understand the status of the current working conditions through a governance lens and brought into context the role of government and its decentralized organs in handling health workers in order to improve their performance and retention. In-depth interviews were conducted with 22 informants (15 health workers, 5 members of Council Health Management Team and 2 informants from the District Executive Director's office). An interview guide was used with questions pertaining to informants' perspective on provision of maternal health care service, working environment, living conditions, handling of staff's financial claims, avenue for sharing concerns, opportunities for training and career progression. Probing questions on how these issues affect the health workers' role of providing maternal health care were employed. Document reviews and observations of health facilities were conducted to supplement the data. The interviews were analysed using a qualitative content analysis approach. Overall, health workers felt abandoned and lost within an unsupportive system they serve. Difficult working and living environments that affect health workers' role of providing maternal health care services were dominant concerns raised from interviews with both health workers and managers. Existence of a bureaucratic and

  10. SeSBench - An initiative to benchmark reactive transport models for environmental subsurface processes

    NASA Astrophysics Data System (ADS)

    Jacques, Diederik

    2017-04-01

    As soil functions are governed by a multitude of interacting hydrological, geochemical and biological processes, simulation tools coupling mathematical models for interacting processes are needed. Coupled reactive transport models are a typical example of such coupled tools mainly focusing on hydrological and geochemical coupling (see e.g. Steefel et al., 2015). Mathematical and numerical complexity for both the tool itself or of the specific conceptual model can increase rapidly. Therefore, numerical verification of such type of models is a prerequisite for guaranteeing reliability and confidence and qualifying simulation tools and approaches for any further model application. In 2011, a first SeSBench -Subsurface Environmental Simulation Benchmarking- workshop was held in Berkeley (USA) followed by four other ones. The objective is to benchmark subsurface environmental simulation models and methods with a current focus on reactive transport processes. The final outcome was a special issue in Computational Geosciences (2015, issue 3 - Reactive transport benchmarks for subsurface environmental simulation) with a collection of 11 benchmarks. Benchmarks, proposed by the participants of the workshops, should be relevant for environmental or geo-engineering applications; the latter were mostly related to radioactive waste disposal issues - excluding benchmarks defined for pure mathematical reasons. Another important feature is the tiered approach within a benchmark with the definition of a single principle problem and different sub problems. The latter typically benchmarked individual or simplified processes (e.g. inert solute transport, simplified geochemical conceptual model) or geometries (e.g. batch or one-dimensional, homogeneous). Finally, three codes should be involved into a benchmark. The SeSBench initiative contributes to confidence building for applying reactive transport codes. Furthermore, it illustrates the use of those type of models for different

  11. Emerging Strategies for Healthy Urban Governance

    PubMed Central

    Hancock, Trevor; Lin, Vivian; Herzog, Andre

    2007-01-01

    Urban health promotion is not simply a matter of the right interventions, or even the necessary resources. Urban (and indeed global) health depends to an important extent on governance, the institutions and processes through which societies manage the course of events. This paper describes the concept of governance, distinguishing between reforms aimed at improving how government works and innovations that more fundamentally reinvent governance by developing new institutions and processes of local stakeholder control. The paper highlights strategies urban governors can use to maximize their influence on the national and international decisions that structure urban life. It concludes with some observations on the limitations of local governance strategies and the importance of establishing a “virtuous circuit” of governance through which urban dwellers play a greater role in the formation and implementation of policy at the national and global levels. PMID:17464568

  12. Optimal joule heating of the subsurface

    DOEpatents

    Berryman, J.G.; Daily, W.D.

    1994-07-05

    A method for simultaneously heating the subsurface and imaging the effects of the heating is disclosed. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

  13. Locating subsurface gravel with thermal imagery

    NASA Technical Reports Server (NTRS)

    Scholen, Douglas E.; Clerke, William H.; Luepke, Douglas E.

    1986-01-01

    A method was discussed for using 6 band thermal imagery to locate subsurface gravel deposits in vegetated areas. Geologic history is reviewed to select potential areas of study. An overflight was made using a thermal scanner. The data were processed with a computerized system to delineate areas showing a quartz signature radiated by a gravel deposit. The method was developed during a search for gravel on National Forest land in Louisiana. Processed data from thermal imagery was compared with known gravel deposits and exploratory drill hole logs. A high correlation was noted for a wide range of deposits, from commercial pits to trace deposits only a foot thick. Overburden at these sites varied from zero to sixty feet, near the maximum annual penetration by the thermal wave. It was concluded that the method can be used to locate buried gravel deposits and that more time and effort are needed to verify the usefulness for developing gravel pits adjacent to proposed construction sites.

  14. On Subsurface Fracture Opening and Closure

    NASA Astrophysics Data System (ADS)

    Wang, Y.

    2016-12-01

    Mechanistic understanding of fracture opening and closure in geologic media is of significant importance to nature resource extraction and waste management, such as geothermal energy extraction, oil/gas production, radioactive waste disposal, and carbon sequestration and storage). A dynamic model for subsurface fracture opening and closure has been formulated. The model explicitly accounts for the stress concentration around individual aperture channels and the stress-activated mineral dissolution and precipitation. A preliminary model analysis has demonstrated the importance of the stress-activated dissolution mechanism in the evolution of fracture aperture in a stressed geologic medium. The model provides a reasonable explanation for some key features of fracture opening and closure observed in laboratory experiments, including a spontaneous switch from a net permeability reduction to a net permeability increase with no changes in a limestone fracture experiment.

  15. Physiologically anaerobic microorganisms of the deep subsurface

    SciTech Connect

    Stevens, S.E. Jr.; Chung, K.T.

    1992-06-01

    A variety of different media were used to isolate facultatively (FAB) and obligately anaerobic bacteria (OAB). These bacteria were isolated from core subsamples obtained from boreholes at the Idaho National Engineering Lab. (INEL) or at the Hanford Lab. (Yakima). Core material was sampled at various depths to 600 feet below the surface. All core samples with culturable bacteria contained at least FAB making thisthe most common physiological type of anaerobic bacteria present in the deep subsurface at these two sites. INEL core samples are characterized by isolates of both FAB and OAB. No isolates of acetogenic, methanogenic, or sulfate reducing bacteria were obtained. Yakima core samples are characterized by a marked predominance of FAB in comparison to OAB. In addition, isolates of acetogenic, methanogenic, and sulfate reducing bacteria were obtained. The Yakima site has the potential for complete anaerobic mineralization of organic compounds whereas this potential appears to be lacking at INEL.

  16. Letter report: Ari Patrinos -- Subsurface bioremediation

    SciTech Connect

    Happer, W.; MacDonald, G.J.; Ruderman, M.A.; Treiman, S.B.

    1995-07-26

    During the past summer, the authors had the opportunity to examine aspects of the remediation program of the Department of Energy (DOE). The most important conclusion that they have come to is that there is an urgent need to mount a comprehensive research program in remediation. It is also clear to them that DOE does not have the funding to carry out a program on the scale that is required. On the other hand, Environmental Management could very well fund such activities. They would hope that in the future there would be close collaboration between Environmental Management and Energy Research in putting together a comprehensive and well thought-out research program. Here, the authors comment on one aspect of remediation: subsurface bioremediation.

  17. Joint inversion for mapping subsurface hydrologicalparameters

    SciTech Connect

    Tseng, Hung-Wen; Lee, Ki Ha

    2001-03-07

    Using electromagnetic (EM) and seismic travel time data and a least-square criteria, a two-dimensional joint inversion algorithm is under development to assess the feasibility of directly mapping subsurface hydrological properties in a crosswell setup. A simplified Archie's law combined with the time average equation relates the magnetic fields and seismic travel time to two hydrological parameters; rock porosity and pore fluid electrical conductivity. For simplicity, the hydrological parameter distributions are assumed to be two-dimensional. Preliminary results show that joint inversion does have better resolving power for the interpretation than using the EM method alone. Various inversion scenarios have been tested, and it has been found that alternately perturbing just one of the two parameters at each iteration gives the best data fit.

  18. Microwave radiometer for subsurface temperature measurement

    NASA Technical Reports Server (NTRS)

    Porter, R. A.; Bechis, K. P.

    1976-01-01

    A UHF radiometer, operating at a frequency of 800 MHz, was modified to provide an integral, three frequency voltage standing wave ratio (VSWR) circuit in the radio frequency (RF) head. The VSWR circuit provides readings of power transmission at the antenna-material interface with an accuracy of plus or minus 5 percent. The power transmission readings are numerically equal to the emissivity of the material under observation. Knowledge of material emissivity is useful in the interpretation of subsurface apparent temperatures obtained on phantom models of biological tissue. The emissivities of phantom models consisting of lean beefsteak were found to lie in the range 0.623 to 0.779, depending on moisture content. Radiometric measurements performed on instrumented phantoms showed that the radiometer was capable of sensing small temperature changes occurring at depths of at least 19 to 30 mm. This is consistent with previously generated data which showed that the radiometer could sense temperatures at a depth of 38 mm.

  19. Repository Subsurface Preliminary Fire Hazard Analysis

    SciTech Connect

    Richard C. Logan

    2001-07-30

    This fire hazard analysis identifies preliminary design and operations features, fire, and explosion hazards, and provides a reasonable basis to establish the design requirements of fire protection systems during development and emplacement phases of the subsurface repository. This document follows the Technical Work Plan (TWP) (CRWMS M&O 2001c) which was prepared in accordance with AP-2.21Q, ''Quality Determinations and Planning for Scientific, Engineering, and Regulatory Compliance Activities''; Attachment 4 of AP-ESH-008, ''Hazards Analysis System''; and AP-3.11Q, ''Technical Reports''. The objective of this report is to establish the requirements that provide for facility nuclear safety and a proper level of personnel safety and property protection from the effects of fire and the adverse effects of fire-extinguishing agents.

  20. Solving subsurface structural problems using a computer

    SciTech Connect

    Witte, D.M. )

    1987-02-01

    Until recently, the solution of subsurface structural problems has required a combination of graphical construction, trigonometry, time, and patience. Recent advances in software available for both mainframe and microcomputers now reduce the time and potential error of these calculations by an order of magnitude. Software for analysis of deviated wells, three point problems, apparent dip, apparent thickness, and the intersection of two planes, as well as the plotting and interpretation of these data can be used to allow timely and accurate exploration or operational decisions. The available computer software provides a set of utilities, or tools, rather than a comprehensive, intelligent system. The burden for selection of appropriate techniques, computation methods, and interpretations still lies with the explorationist user.

  1. Air-water flow in subsurface systems

    NASA Astrophysics Data System (ADS)

    Hansen, A.; Mishra, P.

    2013-12-01

    Groundwater traces its roots to tackle challenges of safe and reliable drinking water and food production. When the groundwater level rises, air pressure in the unsaturated Vadose zone increases, forcing air to escape from the ground surface. Abnormally high and low subsurface air pressure can be generated when the groundwater system, rainfall, and sea level fluctuation are favorably combined [Jiao and Li, 2004]. Through this process, contamination in the form of volatile gases may diffuse from the ground surface into residential areas, or possibly move into groundwater from industrial waste sites. It is therefore crucial to understand the combined effects of air-water flow in groundwater system. Here we investigate theoretically and experimentally the effects of air and water flow in groundwater system.

  2. Optimal joule heating of the subsurface

    DOEpatents

    Berryman, James G.; Daily, William D.

    1994-01-01

    A method for simultaneously heating the subsurface and imaging the effects of the heating. This method combines the use of tomographic imaging (electrical resistance tomography or ERT) to image electrical resistivity distribution underground, with joule heating by electrical currents injected in the ground. A potential distribution is established on a series of buried electrodes resulting in energy deposition underground which is a function of the resistivity and injection current density. Measurement of the voltages and currents also permits a tomographic reconstruction of the resistivity distribution. Using this tomographic information, the current injection pattern on the driving electrodes can be adjusted to change the current density distribution and thus optimize the heating. As the heating changes conditions, the applied current pattern can be repeatedly adjusted (based on updated resistivity tomographs) to affect real time control of the heating.

  3. Microfluidic adhesion induced by subsurface microstructures.

    PubMed

    Majumder, Abhijit; Ghatak, Animangsu; Sharma, Ashutosh

    2007-10-12

    Natural adhesives in the feet of different arthropods and vertebrates show strong adhesion as well as excellent reusability. Whereas the hierarchical structures on the surface are known to have a substantial effect on adhesion, the role of subsurface structures such as the network of microchannels has not been studied. Inspired by these bioadhesives, we generated elastomeric layers with embedded air- or oil-filled microchannels. These adhesives showed remarkable enhancement of adhesion ( approximately 30 times), which results from the crack-arresting properties of the microchannels, together with the surface stresses caused by the capillary force. The importance of the thickness of the adhesive layer, channel diameter, interchannel spacing, and vertical position within the adhesive has been examined for developing an optimal design of this microfluidic adhesive.

  4. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  5. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  6. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  7. 10 CFR 39.45 - Subsurface tracer studies.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Subsurface tracer studies. 39.45 Section 39.45 Energy NUCLEAR REGULATORY COMMISSION LICENSES AND RADIATION SAFETY REQUIREMENTS FOR WELL LOGGING Equipment § 39.45 Subsurface tracer studies. (a) The licensee shall require all personnel handling...

  8. Subsurface Sounding of Mars: The Effects of Surface Roughness

    NASA Technical Reports Server (NTRS)

    Plaut, J. J.; Jordan, R.; Safaeinili, A.; Safaenelli, A.; Seu, R.; Orosei, R.

    2001-01-01

    The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) will conduct a global survey of Mars from the Mars Express Orbiter starting in 2004. The primary objective of the subsurface observations is to detect material interfaces in the upper several kilometers of the crust of Mars, with a particular emphasis on mapping the 3D distribution of water and ice in that portion of the crust. In order to detect subsurface interfaces, the returned echo from the subsurface must be distinguished from noise and clutter, which can arise from a variety of sources. One source of clutter is surface topography that generates backscattered energy at the same time delay as the subsurface region of interest. Surface topography can affect the detectability of subsurface features in several other ways. Surface roughness at scales comparable or somewhat smaller than the radar wavelength reduces the coherency of the wave as it passes the upper interface. Also, surface slope (tilt) at scales of the radar footprint and larger (> 5 km) affects the apparent Doppler signature of the echoes, and effectively disperses the wave transmitted into the subsurface, making processing and interpretation difficult. In this paper, we report on the roughness characteristics of Mars at these various scales as measured by the Mars Global Surveyor Laser Altimeter (MOLA), and consider the implications for achieving the subsurface sounding goals of MARSIS. Additional information is contained in the original extended abstract.

  9. 75 FR 1276 - Requirements for Subsurface Safety Valve Equipment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ... Equipment AGENCY: Minerals Management Service (MMS), Interior. ACTION: Final rule. SUMMARY: The MMS is... Subsurface Safety Valve Equipment (API Spec 14A) into its regulations. The MMS is incorporating the Eleventh.../API Specification 14A, Specification for Subsurface Safety Valve Equipment, Eleventh Edition, October...

  10. Subsurface Mapping: A Question of Position and Interpretation

    ERIC Educational Resources Information Center

    Kellie, Andrew C.

    2009-01-01

    This paper discusses the character and challenges inherent in the graphical portrayal of features in subsurface mapping. Subsurface structures are, by their nature, hidden and must be mapped based on drilling and/or geophysical data. Efficient use of graphical techniques is central to effectively communicating the results of expensive exploration…

  11. Subsurface banding poultry litter impacts greenhouse gas emissions

    USDA-ARS?s Scientific Manuscript database

    The impact subsurface banding poultry litter (PL) has on greenhouse gas emissions is limited. Thus, a study was conducted in established bermudagrass pastures located in Coastal Plain and Piedmont regions to determine the effects subsurface applying PL has on soil flux using two different band spaci...

  12. Subsurface Water Flow and its Subsequent Impact on Chemical Behavior

    USDA-ARS?s Scientific Manuscript database

    The impact of the subsurface stratigraphy on crop growth and agrichemical behavior has been studied for several years at the OPE3 research site located at the USDA-ARS Beltsville Agricultural Research Center, in Beltsville Maryland. This site contains subsurface restricting layers that have been id...

  13. Water and nitrogen requirements of subsurface drip irrigated pomegranate

    USDA-ARS?s Scientific Manuscript database

    Surface drip irrigation is a well-developed practice for both annual and perennial crops. The use of subsurface drip is a well-established practice in many annual row crops, e.g. tomatoes, strawberries, lettuce. However, the use of subsurface drip on perennial crops has been slow to develop. With th...

  14. DEMONSTRATION BULLETIN: SUBSURFACE VOLATILIZATION AND VENTILATION SYSTEM - BROWN & ROOT ENVIRONMENTAL

    EPA Science Inventory

    The Subsurface Volatilization and Ventilation System (SVVS*) is an in-situ vacuum extraction/air sparging and bioremediation technology for the treatment of subsurface organic contamination in soil and groundwater. The technology, developed by Billings and Associates, Inc., and o...

  15. Agriculture and wildlife: ecological implications of subsurface irrigation drainage

    Treesearch

    A. Dennis Lemly

    1994-01-01

    Subsurface agricultural irrigation drainage is a wastewater with the potential to severely impact wetlands and wildlife populations. Widespread poisoning of migratory birds by drainwater contaminants has occurred in the western United States and waterfowl populations are threatened in the Pacific and Central flyways. Irrigated agriculture could produce subsurface...

  16. The distribution of subsurface damage in fused silica

    SciTech Connect

    Miller, P E; Suratwala, T I; Wong, L L; Feit, M D; Menapace, J A; Davis, P J; Steele, R A

    2005-11-21

    Managing subsurface damage during the shaping process and removing subsurface damage during the polishing process is essential in the production of low damage density optical components, such as those required for use on high peak power lasers. Removal of subsurface damage, during the polishing process, requires polishing to a depth which is greater than the depth of the residual cracks present following the shaping process. To successfully manage, and ultimately remove subsurface damage, understanding the distribution and character of fractures in the subsurface region introduced during fabrication process is important. We have characterized the depth and morphology of subsurface fractures present following fixed abrasive and loose abrasive grinding processes. At shallow depths lateral cracks and an overlapping series of trailing indentation fractures were found to be present. At greater depths, subsurface damage consists of a series of trailing indentation fractures. The area density of trailing fractures changes as a function of depth, however the length and shape of individual cracks remain nearly constant for a given grinding process. We have developed and applied a model to interpret the depth and crack length distributions of subsurface surface damage in terms of key variables including abrasive size and load.

  17. Subsurface Mapping: A Question of Position and Interpretation

    ERIC Educational Resources Information Center

    Kellie, Andrew C.

    2009-01-01

    This paper discusses the character and challenges inherent in the graphical portrayal of features in subsurface mapping. Subsurface structures are, by their nature, hidden and must be mapped based on drilling and/or geophysical data. Efficient use of graphical techniques is central to effectively communicating the results of expensive exploration…

  18. Subsurface Controls on Habitability of Hydrothermal Waters

    NASA Astrophysics Data System (ADS)

    Fristad, K. E.; Som, S. M.; Hoehler, T. M.

    2014-12-01

    Liquid water alone does not make an environment habitable. Environmental settings dominated by water-rock reactions such as in hydrothermal vents and springs are natural targets for astrobiological investigation of waterworlds because the rich geochemical diversity at these locales provides abundant energy in solvent to support microbial life. Hydrogen oxidizers are of particular interest because H2-based metabolisms are widespread and deeply rooted throughout the phylogenetic tree of life, implying they may have emerged extremely early in the evolution, and possibly even the origin, of life on Earth and potentially any other rocky bodies bearing liquid water. Dihydrogen (H2) can be lithogenically produced by the hydrolytic oxidation of the ferrous iron component in Fe-bearing minerals as well as by radiolytic cleavage of water by α, β, or γ radiation produced during the decay of radioactive isotopes. Lithogenic H2 production mechanisms operate across a range of rock types, but the concentration of dissolved H2 available to life is controlled by a number of subsurface factors such as surface geometry, water to rock ratio, production rate, and fluid flux. These factors are often controlled by the larger geologic and structural context of a particular site. We present results of an ongoing project that surveys H2 concentrations from terrestrial hydrothermal waters in diverse chemical and physical settings. Aqueous H2 concentrations and potential subsurface controls are presented for sites across the western U.S. including Yellowstone National Park, Lassen Volcanic National Park, and Iceland. In coordination with field data, we also investigate the habitability of various sites numerically by coupling a geochemical model of water-rock interaction with that of single-cell methanogenesis and compute a habitability index for the given environment. In particular, we investigate the control that temperature, rock composition, water composition, and water to rock ratio

  19. Subsurface Carbon Cycling Below the Root Zone

    NASA Astrophysics Data System (ADS)

    Wan, J.; Dong, W.; Kim, Y.; Tokunaga, T. K.; Bill, M.; Conrad, M. E.; Williams, K. H.; Long, P. E.; Hubbard, S. S.

    2014-12-01

    Carbon in the subsurface below the root zone is an important yet poorly understood link in the terrestrial C cycle, interfacing between overlying soil and downstream aquatic systems. Thus, the nature and behavior of C in the vadose zone and groundwater, particularly the dynamics of mobile dissolved and suspended aqueous species, need to be understood for predicting C cycling and responses to climate change. This study is designed to understand the C balance (influxes, effluxes, and sequestration) and mechanisms controlling subsurface organic and inorganic C transport and transformation. Our initial investigations are being conducted at the Rifle Site floodplain along the Colorado River, in Colorado (USA). Within this floodplain, sediment samples were collected and sampling/monitoring instruments were installed down to 7 m depth at three sites. Pore water and gas samplers at 0.5 m depth intervals within the ~3.5 m deep vadose zone, and multilevel aquifer samplers have yielded depth- and time-resolved profiles of dissolved and suspended organic and inorganic C, and CO2 for over 1.5 years. Analyses conducted to determine seasonally and vertically resolved geochemical profiles show that dissolved organic matter (DOM) characteristics vary among three distinct hydrobiogeochemical zones; the vadose zone, capillary fringe, and saturated zone. The concentrations of dissolved organic matter (DOM) are many times higher in the vadose zone and the capillary fringe than in groundwater, and vary seasonally. The DOM speciation, aqueous geochemistry, solid phase analyses, and d13C isotope data show the importance of both biotic and abiotic C transformations during transport through the vertical gradients of moisture and temperature. In addition to DOM, suspended organic C and bacteria have been collected from samplers within the capillary fringe. Based on the field-based findings, long-term laboratory column experiments are being conducted under simulated field moisture

  20. Accelerating Subsurface Transport Simulation on Heterogeneous Clusters

    SciTech Connect

    Villa, Oreste; Gawande, Nitin A.; Tumeo, Antonino

    2013-09-23

    Reactive transport numerical models simulate chemical and microbiological reactions that occur along a flowpath. These models have to compute reactions for a large number of locations. They solve the set of ordinary differential equations (ODEs) that describes the reaction for each location through the Newton-Raphson technique. This technique involves computing a Jacobian matrix and a residual vector for each set of equation, and then solving iteratively the linearized system by performing Gaussian Elimination and LU decomposition until convergence. STOMP, a well known subsurface flow simulation tool, employs matrices with sizes in the order of 100x100 elements and, for numerical accuracy, LU factorization with full pivoting instead of the faster partial pivoting. Modern high performance computing systems are heterogeneous machines whose nodes integrate both CPUs and GPUs, exposing unprecedented amounts of parallelism. To exploit all their computational power, applications must use both the types of processing elements. For the case of subsurface flow simulation, this mainly requires implementing efficient batched LU-based solvers and identifying efficient solutions for enabling load balancing among the different processors of the system. In this paper we discuss two approaches that allows scaling STOMP's performance on heterogeneous clusters. We initially identify the challenges in implementing batched LU-based solvers for small matrices on GPUs, and propose an implementation that fulfills STOMP's requirements. We compare this implementation to other existing solutions. Then, we combine the batched GPU solver with an OpenMP-based CPU solver, and present an adaptive load balancer that dynamically distributes the linear systems to solve between the two components inside a node. We show how these approaches, integrated into the full application, provide speed ups from 6 to 7 times on large problems, executed on up to 16 nodes of a cluster with two AMD Opteron 6272

  1. Imaging the Subsurface with Upgoing Muons

    NASA Astrophysics Data System (ADS)

    Bonal, N.; Preston, L. A.; Schwellenbach, D.; Dreesen, W.; Green, A.

    2014-12-01

    We assess the feasibility of imaging the subsurface using upgoing muons. Traditional muon imaging focuses on more-prevalent downgoing muons. Muons are subatomic particles capable of penetrating the earth's crust several kilometers. Downgoing muons have been used to image the Pyramid of Khafre of Giza, various volcanoes, and smaller targets like cargo. Unfortunately, utilizing downgoing muons requires below-target detectors. For aboveground objects like a volcano, the detector is placed at the volcano's base and the top portion of the volcano is imaged. For underground targets like tunnels, the detector would have to be placed below the tunnel in a deeper tunnel or adjacent borehole, which can be costly and impractical for some locations. Additionally, detecting and characterizing subsurface features like voids from tunnels can be difficult. Typical characterization methods like sonar, seismic, and ground penetrating radar have shown mixed success. Voids have a marked density contrast with surrounding materials, so using methods sensitive to density variations would be ideal. High-energy cosmic ray muons are more sensitive to density variation than other phenomena, including gravity. Their absorption rate depends on the density of the materials through which they pass. Measurements of muon flux rate at differing directions provide density variations of the materials between the muon source (cosmic rays and neutrino interactions) and detector, much like a CAT scan. Currently, tomography using downgoing muons can resolve features to the sub-meter scale. We present results of exploratory work, which demonstrates that upgoing muon fluxes appear sufficient to achieve target detection within a few months. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  2. Transformative environmental governance

    EPA Science Inventory

    Transformative governance is an approach to environmental governance that has the capacity to respond to, manage, and trigger regime shifts in coupled social-ecological systems (SESs) at multiple scales. The goal of transformative governance is to actively shift degraded SESs to ...

  3. Governance is Academic.

    ERIC Educational Resources Information Center

    Manahan, Richard A.; And Others

    1985-01-01

    A model for systematic development and reorganization of college governance systems consists of three processes: reviewing the existing governance structure; examining the concerns and interrelationships of individuals and groups; and pinpointing desired changes. All must be done in the context of linking governance to overall institutional…

  4. Teaching about Comparative Government

    ERIC Educational Resources Information Center

    Risinger, C. Frederick

    2009-01-01

    As international relationships become increasingly important (with both friendly and not-so-friendly governments), the author believes that it is important for U.S. students to learn about how a parliamentary democracy works--how it is similar, but different from a presidential-style government. Learning about the systems of government of other…

  5. Modelling University Governance

    ERIC Educational Resources Information Center

    Trakman, Leon

    2008-01-01

    Twentieth century governance models used in public universities are subject to increasing doubt across the English-speaking world. Governments question if public universities are being efficiently governed; if their boards of trustees are adequately fulfilling their trust obligations towards multiple stakeholders; and if collegial models of…

  6. Modelling University Governance

    ERIC Educational Resources Information Center

    Trakman, Leon

    2008-01-01

    Twentieth century governance models used in public universities are subject to increasing doubt across the English-speaking world. Governments question if public universities are being efficiently governed; if their boards of trustees are adequately fulfilling their trust obligations towards multiple stakeholders; and if collegial models of…

  7. Transformative environmental governance

    EPA Science Inventory

    Transformative governance is an approach to environmental governance that has the capacity to respond to, manage, and trigger regime shifts in coupled social-ecological systems (SESs) at multiple scales. The goal of transformative governance is to actively shift degraded SESs to ...

  8. Teaching about Comparative Government

    ERIC Educational Resources Information Center

    Risinger, C. Frederick

    2009-01-01

    As international relationships become increasingly important (with both friendly and not-so-friendly governments), the author believes that it is important for U.S. students to learn about how a parliamentary democracy works--how it is similar, but different from a presidential-style government. Learning about the systems of government of other…

  9. Taking Student Government Seriously.

    ERIC Educational Resources Information Center

    Bolen, J. R.

    1999-01-01

    Discusses the student government at La Mesa Middle School (California) that was modeled after the three-branch U.S. government as a means for increasing students' civic understanding. Describes the structure of the legislative, judicial, and executive branches, the different activities of the student government, and the reasons for the hiatus.…

  10. Wyoming Government, Unit VII.

    ERIC Educational Resources Information Center

    Robinson, Terry

    This unit on Wyoming government presents concepts, activities, and stories for elementary school students. Concepts stress that the functions of government are determined according to the demands, needs, and traditions of the people; each part of government has a special function; as citizens, we should be loyal to the underlying concepts of our…

  11. Variation in energy available to populations of subsurface anaerobes in response to geological carbon storage.

    PubMed

    Kirk, Matthew F

    2011-08-01

    Microorganisms can strongly influence the chemical and physical properties of the subsurface. Changes in microbial activity caused by geological CO(2) storage, therefore, have the potential to influence the capacity, injectivity, and integrity of CO(2) storage reservoirs and ultimately the environmental impact of CO(2) injection. This analysis uses free energy calculations to examine variation in energy available to Fe(III) and SO(4)(2-) reducers and methanogens because of changes in the bulk composition of brine and shallow groundwater following subsurface CO(2) injection. Calculations were performed using data from two field experiments, the Frio Formation experiment and an experiment at the Zero Emission Research and Technology test site. Energy available for Fe(III) reduction increased significantly during CO(2) injection in both experiments, largely because of a decrease in pH from near-neutral levels to just below 6. Energy available to SO(4)(2-) reducers and methanogens varied little. These changes can lead to a greater rate of microbial Fe(III) reduction following subsurface CO(2) injection in reservoirs where Fe(III) oxides or oxyhydroxides are available and the rate of Fe(III) reduction is limited by energy available prior to injection.

  12. Quantitative sub-surface and non-contact imaging using scanning microwave microscopy

    NASA Astrophysics Data System (ADS)

    Gramse, Georg; Brinciotti, Enrico; Lucibello, Andrea; Patil, Samadhan B.; Kasper, Manuel; Rankl, Christian; Giridharagopal, Rajiv; Hinterdorfer, Peter; Marcelli, Romolo; Kienberger, Ferry

    2015-03-01

    The capability of scanning microwave microscopy for calibrated sub-surface and non-contact capacitance imaging of silicon (Si) samples is quantitatively studied at broadband frequencies ranging from 1 to 20 GHz. Calibrated capacitance images of flat Si test samples with varying dopant density (1015-1019 atoms cm-3) and covered with dielectric thin films of SiO2 (100-400 nm thickness) are measured to demonstrate the sensitivity of scanning microwave microscopy (SMM) for sub-surface imaging. Using standard SMM imaging conditions the dopant areas could still be sensed under a 400 nm thick oxide layer. Non-contact SMM imaging in lift-mode and constant height mode is quantitatively demonstrated on a 50 nm thick SiO2 test pad. The differences between non-contact and contact mode capacitances are studied with respect to the main parameters influencing the imaging contrast, namely the probe tip diameter and the tip-sample distance. Finite element modelling was used to further analyse the influence of the tip radius and the tip-sample distance on the SMM sensitivity. The understanding of how the two key parameters determine the SMM sensitivity and quantitative capacitances represents an important step towards its routine application for non-contact and sub-surface imaging.

  13. Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration.

    PubMed

    Guillon, Sophie; Sun, Yunwei; Purtschert, Roland; Raghoo, Lauren; Pili, Eric; Carrigan, Charles R

    2016-05-01

    High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Subsurface Structural Control on Folding and Fracturing at Sheep Mountain Anticline, Wyoming

    NASA Astrophysics Data System (ADS)

    Fiore, P. E.; Bellahsen, N.; Pollard, D. D.

    2005-12-01

    Recent field studies at Sheep Mountain Anticline, a Laramide fold on the eastern flank of the Bighorn Basin in Wyoming, constrain the fold kinematics using the fracture pattern mapped across the fold. Modeling studies point to the influence of the elastic stress perturbations induced by slip along the underlying faults on this fracturing. The timing (and master-splay) relationship between the underlying faults has important implications for the mechanism of formation of the mapped fracture sets, but existing interpretations of these faults are in conflict. We present eleven reprocessed, depth migrated 2D seismic reflection profiles that were acquired in the vicinity of Sheep Mountain Anticline in the early 1980s. Three profiles show the subsurface structure along the trend of the fold axis; eight profiles show the subsurface structure perpendicular to the fold axis. From interpretations of the seismic profiles, we develop a 3D model of the fault geometry beneath Sheep Mountain Anticline. The most probable master-splay fault relationship is determined through geomechanical modeling. A forward model is run for each of the possible fault geometries, and the deformed shapes of representative modeled horizons are compared with horizons interpreted from the 2D seismic profiles. The elastic stress perturbations resulting from slip along the faults in the most probable configuration is then calculated and compared to the mapped fracture pattern. In this way, the influence of underlying faults on the exposed fracturing at Sheep Mountain Anticline is reassessed using geomechanical models with subsurface constraints.

  15. The InSight Mars Lander and Its Effect on the Subsurface Thermal Environment

    NASA Astrophysics Data System (ADS)

    Siegler, Matthew A.; Smrekar, Suzanne E.; Grott, Matthias; Piqueux, Sylvain; Mueller, Nils; Williams, Jean-Pierre; Plesa, Ana-Catalina; Spohn, Tilman

    2017-02-01

    The 2018 InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) Mission has the mission goal of providing insitu data for the first measurement of the geothermal heat flow of Mars. The Heat Flow and Physical Properties Package (HP3) will take thermal conductivity and thermal gradient measurements to approximately 5 m depth. By necessity, this measurement will be made within a few meters of the lander. This means that thermal perturbations from the lander will modify local surface and subsurface temperature measurements. For HP3's sensitive thermal gradient measurements, this spacecraft influence will be important to model and parameterize. Here we present a basic 3D model of thermal effects of the lander on its surroundings. Though lander perturbations significantly alter subsurface temperatures, a successful thermal gradient measurement will be possible in all thermal conditions by proper ( >3 m depth) placement of the heat flow probe.

  16. Developing Ocean Subsurface Data Record from CALIPSO Depolarization Ratio Measurements

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Rodier, S. D.; Zhai, P.; Josset, D. B.; Omar, A. H.

    2012-12-01

    CALIOP, the dual wavelength, polarization sensitive lidar flying aboard the CALIPSO satellite, has been operating since June 2006 and is expected to continue for several more years. CALIOP's depolarization ratio is one of the best calibrated measurements made by the A-Train sensors. Over the life of the CALIPSO mission, the stability of the CALIOP depolarization ratio calibration has remained within 1%. CALIOP's depolarization ratio measurements can be used for studying changes in the backscatter of ocean subsurface particulates. The ocean surface/subsurface depolarization ratio measurements from CALIOP together with collocated A-train instruments can be used for estimating the subsurface particulate backscatter coefficient (bbp) and the cross polarization component of the column integrated ocean subsurface backscatter signal. To derive the cross component of inte¬grated ocean subsurface backscatter signal from the depolarization ratio of CALIOP integrated ocean surface/subsurface range bins, we need theoretical estimates of the ocean surface back¬scatter cross section, which can be derived accurately from CloudSat ocean surface backscatter measurements or from AMSR-E wind speeds. Using the CALIOP cross component of the integrated ocean subsurface backscatter together with diffuse attenuation coefficient derived from MODIS, bbp can be estimated. Preliminary CALIOP data analysis shows that in the Southern Oceans, ocean subsurface backscatter has increased by about 5% since the beginning of the CALIPSO mission in June 2006. This study will: (1) introduce the CALIPSO ocean subsurface backscatter data products; (2) assess the uncertainties in the data products and comparing with in situ optics measurements, radiative transfer modeling and aircraft lidar measurements; and (3) summarize the global and regional (e.g., Gulf of Mexico region) statistics and temporal variations of the ocean subsurface backscatter from CALIPSO measurements.

  17. Denitrifying bacteria from the genus Rhodanobacter dominate bacterial communities in the highly contaminated subsurface of a nuclear legacy waste site

    SciTech Connect

    Green, Stefan; Prakash, Om; Jasrotia, Puja; Overholt, Will; Cardenas, Erick; Hubbard, Daniela; Tiedje, James M.; Watson, David B; Schadt, Christopher Warren; Brooks, Scott C; Kostka, Joel

    2011-01-01

    The effect of long-term mixed-waste contamination, particularly uranium and nitrate, on the microbial community in the terrestrial subsurface was investigated at the field scale at the Oak Ridge Integrated Field Research Challenge (ORIFRC) site in Oak Ridge, TN. The abundance, community composition, and distribution of groundwater microorganisms were examined across the site during two seasonal sampling events. At representative locations, subsurface sediment was also examined from two boreholes, one sampled from the most heavily contaminated area of the site and another from an area with low contamination. A suite of DNA- and RNA-based molecular tools were employed for community characterization, including quantitative PCR of ribosomal RNA and nitrite reductase genes, community composition fingerprinting analysis, and high-throughput pyrotag sequencing of rRNA genes. The results demonstrate that pH is a major driver of the subsurface microbial community structure, and denitrifying bacteria from the genus Rhodanobacter (class Gammaproteobacteria) dominate at low pH. The relative abundance of bacteria from this genus was positively correlated with lower pH conditions, and these bacteria were abundant and active in the most highly contaminated areas. Other factors, such as concentration of nitrogen species, oxygen and sampling season did not appear to strongly influence the distribution of Rhodanobacter. Results indicate that these organisms are acid-tolerant denitrifiers, well suited to the acidic, nitrate-rich subsurface conditions, and pH is confirmed as a dominant driver of bacterial community structure in this contaminated subsurface environment.

  18. Overview of research and development in subsurface fate and transport modeling

    SciTech Connect

    Sullivan, T.M.; Chehata, M.

    1995-05-01

    The US Department of Energy is responsible for the remediation of over 450 different subsurface-contaminated sites. Contaminant plumes at these sites range in volume from several to millions of cubic yards. The concentration of contaminants also ranges over several orders of magnitude. Contaminants include hazardous wastes such as heavy metals and organic chemicals, radioactive waste including tritium, uranium, and thorium, and mixed waste, which is a combination of hazardous and radioactive wastes. The physical form of the contaminants includes solutes, nonaqueous phase liquids (NAPLs), and vapor phase contaminants such as volatilized organic chemicals and radon. The subject of contaminant fate and transport modeling is multi-disciplinary, involving hydrology, geology, microbiology, chemistry, applied mathematics, computer science, and other areas of expertise. It is an issue of great significance in the United States and around the world. As such, many organizations have substantial programs in this area. In gathering data to prepare this report, a survey was performed of research and development work that is funded by US government agencies to improve the understanding and mechanistic modeling of processes that control contaminant movement through subsurface systems. Government agencies which fund programs that contain fate and transport modeling components include the Environmental Protection Agency, Nuclear Regulatory Commission, Department of Agriculture, Department of Energy, National Science Foundation, Department of Defense, United States Geological Survey, and National Institutes of Health.

  19. Armored Enzyme Nanoparticles for Remediation of Subsurface Contaminants

    SciTech Connect

    Jonathan S. Dordick; Jay Grate; Jungbae Kim

    2007-02-19

    The remediation of subsurface contaminants is a critical problem for the Department of Energy, other government agencies, and our nation. Severe contamination of soil and groundwater exists at several DOE sites due to various methods of intentional and unintentional release. Given the difficulties involved in conventional removal or separation processes, it is vital to develop methods to transform contaminants and contaminated earth/water to reduce risks to human health and the environment. Transformation of the contaminants themselves may involve conversion to other immobile species that do not migrate into well water or surface waters, as is proposed for metals and radionuclides; or degradation to harmless molecules, as is desired for organic contaminants. Transformation of contaminated earth (as opposed to the contaminants themselves) may entail reductions in volume or release of bound contaminants for remediation. Research at Rensselaer focused on the development of haloalkane dehalogenase as a critical enzyme in the dehalogenation of contaminated materials (ultimately trichloroethylene and related pollutants). A combination of bioinformatic investigation and experimental work was performed. The bioinformatics was focused on identifying a range of dehalogenase enzymes that could be obtained from the known proteomes of major microorganisms. This work identified several candidate enzymes that could be obtained through relatively straightforward gene cloning and expression approaches. The experimental work focused on the isolation of haloalkane dehalogenase from a Xanthobacter species followed by incorporating the enzyme into silicates to form biocatalytic silicates. These are the precursors of SENs. At the conclusion of the study, dehalogenase was incorporated into SENs, although the loading was low. This work supported a single Ph.D. student (Ms. Philippa Reeder) for two years. The project ended prior to her being able to perform substantive bioinformatics

  20. RADIOIODINE GEOCHEMISTRY IN THE SRS SUBSURFACE ENVIRONMENT

    SciTech Connect

    Kaplan, D.; Emerson, H.; Powell, B.; Roberts, K.; Zhang, S.; Xu, C.; Schwer, K.; Li, H.; Ho, Y.; Denham, M.; Yeager, C.; Santschi, P.

    2013-05-16

    Iodine-129 is one of the key risk drivers for several Savannah River Site (SRS) performance assessments (PA), including that for the Low-Level Waste Disposal Facility in E-Area. In an effort to reduce the uncertainty associated with the conceptual model and the input values used in PA, several studies have recently been conducted dealing with radioiodine geochemistry at the SRS. The objective of this report was to review these recent studies and evaluate their implications on SRS PA calculations. For the first time, these studies measured iodine speciation in SRS groundwater and provided technical justification for assuming the presence of more strongly sorbing species (iodate and organo-iodine), and measured greater iodine sediment sorption when experiments included these newly identified species; specifically they measured greater sorption coefficients (K{sub d} values: the concentration ratio of iodine on the solid phase divided by the concentration in the aqueous phase). Based on these recent studies, new best estimates were proposed for future PA calculations. The new K{sub d} values are greater than previous recommended values. These proposed K{sub d} values reflect a better understanding of iodine geochemistry in the SRS subsurface environment, which permits reducing the associated conservatism included in the original estimates to account for uncertainty. Among the key contributing discoveries supporting the contention that the K{sub d} values should be increased are that: 1) not only iodide (I{sup -}), but also the more strongly sorbing iodate (IO{sub 3}{sup -}) species exists in SRS groundwater (average total iodine = 15% iodide, 42% iodate, and 43% organoiodine), 2) when iodine was added as iodate, the measured K{sub d} values were 2 to 6 times greater than when the iodine was added as iodide, and perhaps most importantly, 3) higher desorption (10 to 20 mL/g) than (ad)sorption (all previous studies) K{sub d} values were measured. The implications of this