WorldWideScience

Sample records for ground surface due

  1. Ground Surface Deformation around Tehran due to Groundwater Recharge: InSAR Monitoring.

    Science.gov (United States)

    Gourmelen, N.; Peyret, M.; Fritz, J. F.; Cherry, J.

    2003-04-01

    Tehran is located on an active tectonic and seismic zone. The surface deformation monitoring provides a powerful tool for getting a better understanding of faults kinematics and mechanisms. Used in conjunction with GPS networks, InSAR (Interferometric Synthetic Aperture Radar) provides dense and precise deformation measurements which are essential for mapping complex heterogeneous deformation fields. Moreover, urban and arid areas preserve interferometric phase coherence. The archived acquisitions of ERS that span 9 months between September 1998 and June 1999 reveal wide areas of surface uplift (by as much as 9 cm). This vertical deformation (gradual in time) has probably no tectonic meaning but is rather the ground response to ground water recharge. These zones are all located dowstream of large alluvial fans like the one of Karaj. The variation of effective stress caused by intersticial water draining could explain such surface deformation. It can also be noticed that some faults act as boundary for these deformation zones and fluid motion. The understanding of this deformation is relevant for groundwater monitoring and urban developement management. It is also necessary for discriminating it from tectonic deformation that also occurs on this zone. Due to the lack of attitude control of satellite ERS-2 since February 2001, the last images acquired could not be combined with the former acquisitions. Nevertheless, we expect to be able to enrich our set of images in order to map tectonic deformation on a longer period and to monitor in a more continuous way the deformation due to groundwater evolution. This would allow to quantify the permanent and reversible part of this signal.

  2. Numerical modelling of ground-borne noise and vibration in buildings due to surface rail traffic

    Science.gov (United States)

    Fiala, P.; Degrande, G.; Augusztinovicz, F.

    2007-04-01

    This paper deals with the numerical computation of the structural and acoustic response of a building to an incoming wave field generated by high-speed surface railway traffic. The source model consists of a moving vehicle on a longitudinally invariant track, coupled to a layered ground modelled with a boundary element formulation. The receiver model is based on a substructuring formulation and consists of a boundary element model of the soil and a finite element model of the structure. The acoustic response of the building's rooms is computed by means of a spectral finite element formulation. The paper investigates the structural and acoustic response of a multi-story portal frame office building up to a frequency of 150 Hz to the passage of a Thalys high-speed train at constant velocity. The isolation performance of three different vibration countermeasures: a floating-floor, a room-in-room, and base-isolation, are examined.

  3. Effect of the surface geology on strong ground motions due to the 2016 Central Tottori Earthquake, Japan

    Science.gov (United States)

    Kagawa, Takao; Noguchi, Tatsuya; Yoshida, Shohei; Yamamoto, Shinji

    2017-08-01

    On October 21, 2016, an earthquake with Japan Meteorological Agency (JMA) magnitude 6.6 hit the central part of Tottori Prefecture, Japan. This paper demonstrates two notable effects of the surface geology on strong ground motions due to the earthquake. One is a predominant period issue observed over a large area. A seismic intensity of 6 lower on the JMA scale was registered at three sites in the disaster area. However, the peak ground acceleration ranged from 0.3 to 1.4 G at the three sites because of the varying peak periods of observed strong ground motions. The spectral properties of the observations also reflect the damage around the sites. Three-component microtremors were observed in the area; the predominant ground period distributions based on horizontal to vertical spectral ratios were provided by the authors. The peak periods of the strong motion records agree well with predominant periods estimated from microtremor observations at a rather hard site; however, the predominant periods of the microtremors are slightly shorter than those of the main shock at the other two soft sites. We checked the nonlinear effect at the sites by comparing the site responses to small events and the main shock. The peak periods of the main shock were longer than those of the weak motions at the sites. This phenomenon indicates a nonlinear site effect due to large ground motions caused by the main shock. A horizontal component of the accelerogram showed rather pulsating swings that indicate cyclic mobility behavior, especially at a site close to a pond shore; ground subsidence of 20 cm was observed around the site. The peak periods of weak motions agree well with those of the microtremor observations. This implies an important issue that the predominant periods estimated by microtremors are not sufficient to estimate the effect of surface geology for disaster mitigation. We have to estimate the predominant periods under large ground motions considering the nonlinear site

  4. Temperature rise in objects due to optical focused beam through atmospheric turbulence near ground and ocean surface

    Science.gov (United States)

    Stoneback, Matthew; Ishimaru, Akira; Reinhardt, Colin; Kuga, Yasuo

    2013-03-01

    We consider an optical beam propagated through the atmosphere and incident on an object causing a temperature rise. In clear air, the physical characteristics of the optical beam transmitted to the object surface are influenced primarily by the effect of atmospheric turbulence, which can be significant near the ground or ocean surface. We use a statistical model to quantify the expected power transfer through turbulent atmosphere and provide guidance toward the threshold of thermal blooming for the considered scenarios. The bulk thermal characteristics of the materials considered are used in a thermal diffusion model to determine the net temperature rise at the object surface due to the incident optical beam. These results of the study are presented in graphical form and are of particular interest to operators of high power laser systems operating over large distances through the atmosphere. Numerical examples include a CO2 laser (λ=10.6 μm) with: aperture size of 5 cm, varied pulse duration, and propagation distance of 0.5 km incident on 0.1-mm copper, 10-mm polyimide, 1-mm water, and 10-mm glass/resin composite targets. To assess the effect of near ground/ocean laser propagation, we compare turbulent (of varying degrees) and nonturbulent atmosphere.

  5. Where’s the Ground Surface? – Elevation Bias in LIDAR-derived Digital Elevation Models Due to Dense Vegetation in Oregon Tidal Marshes

    Science.gov (United States)

    Light Detection and Ranging (LIDAR) is a powerful resource for coastal and wetland managers and its use is increasing. Vegetation density and other land cover characteristics influence the accuracy of LIDAR-derived ground surface digital elevation models; however the degree to wh...

  6. Attenuation of ground vibrations due to different technical sources

    Institute of Scientific and Technical Information of China (English)

    L. Auersch; S. Said

    2010-01-01

    The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation v ~ r where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp(-kr), but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading.

  7. Contamination of Ground Water Due To Landfill Leachate

    Directory of Open Access Journals (Sweden)

    M. V. S. Raju

    2012-12-01

    Full Text Available The present site under investigation at Ajitsingh Nagar in Vijayawada of Andhra Pradesh is initially a low lying area and used for disposing the urban solid waste for the last few years, through open dumping with out taking any measures to protect the Ground water against pollution. The present study has been taken up to measure the degree of pollution of ground water due to leachate produced in the landfill site. Bore holes were made at eight random locations to measure the depth and characteristics of solid waste. Four sampling wells were made for the collection of ground water samples and they were analyzed for various parameters. All parameters were measured based on Standard methods. It is found that the ground water is contaminated due leachates of Landfill to the large extent and is not suitable for Drinking, Domestic and Irrigation purposes.

  8. Effects of soil amplification ratio and multiple wave interference for ground motion due to earthquake

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhixin; XU Jiren; Ryuji Kubota

    2004-01-01

    Influences on the ground motion simulations by soil amplification effects and multiple seismic wave interferences in the heterogeneous medium are investigated. Detailed velocity structure obtained from the microtremor array survey is adopted in the ground motion simulation. Analyses for amplification ratios of core samples of ten drill holes with 40 m deep in the sedimentary layers show that the soil amplification ratio influences nonlinearly the seismic ground motion. Based on the above analysis results, the ground motion in the heavily damaged zone in the Japanese Kobe earthquake of 1995 is simulated in a digital SH seismic wave model by using the pseudospectral method with the staggered grid RFFT differentiation (SGRFFTD). The simulated results suggest that the heterogeneous velocity structure results in a complicated distribution of the maximum amplitudes of acceleration waveforms with multiple peaks at the surface. Spatial distribution of the maximum amplitudes coincides well with that of collapse ratios of buildings in Kobe. The dual peaks of the collapse ratios away from the earthquake fault coincide well with the double peak amplitudes of simulated seismic acceleration waves also. The cause for the first peak amplitude of the ground motion is attributable to the interference of the secondary surface wave from the bedrock propagating horizontally along the surface sedimentary layer and the body wave from the basin bottom according to analyses of wave snapshots propagating in inhomogeneous structure of the Osaka group layers. The second peak amplitude of the ground motion may be attributive to the interference of the secondary surface wave from the tunneling waves in the shallow sediments and the body wave. It is important for the study on complicated distributions of earthquake damages to investigate influences on the ground motion by soil amplification effects and multiple seismic wave interferences due to the structure. Explorations of the structure to the

  9. Artificial Ground Water Recharge with Surface Water

    Science.gov (United States)

    Heviánková, Silvie; Marschalko, Marian; Chromíková, Jitka; Kyncl, Miroslav; Korabík, Michal

    2016-10-01

    With regard to the adverse manifestations of the recent climatic conditions, Europe as well as the world have been facing the problem of dry periods that reduce the possibility of drawing drinking water from the underground sources. The paper aims to describe artificial ground water recharge (infiltration) that may be used to restock underground sources with surface water from natural streams. Among many conditions, it aims to specify the boundary and operational conditions of the individual aspects of the artificial ground water recharge technology. The principle of artificial infiltration lies in the design of a technical system, by means of which it is possible to conduct surplus water from one place (in this case a natural stream) into another place (an infiltration basin in this case). This way, the water begins to infiltrate into the underground resources of drinking water, while the mixed water composition corresponds to the water parameters required for drinking water.

  10. Practical aspects of tritium measurement in ground and surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Nitzsche, O. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Angewandte Physik; Hebert, D. [Technische Univ. Bergakademie Freiberg (Germany). Inst. fuer Angewandte Physik

    1997-03-01

    Tritium measurements are a powerful tool in hydrological and hydrogeological investigations for detecting mean residence times of several water reservoirs. Due to the low tritium activities in precipitation, ground and surface waters a low level measurement is necessary. Therefore often the liquid scintillation counting after an electrolytic enrichment of water is used. In this paper some practical aspects and problems of measurement are discussed and the problem of contamination in low level laboratories is shown. (orig.)

  11. Bacteriophages as surface and ground water tracers

    Directory of Open Access Journals (Sweden)

    P. Rossi

    1998-01-01

    Full Text Available Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra. In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  12. Bacteriophages as surface and ground water tracers

    Science.gov (United States)

    Rossi, P.; Dörfliger, N.; Kennedy, K.; Müller, I.; Aragno, M.

    Bacteriophages are increasingly used as tracers for quantitative analysis in both hydrology and hydrogeology. The biological particles are neither toxic nor pathogenic for other living organisms as they penetrate only a specific bacterial host. They have many advantages over classical fluorescent tracers and offer the additional possibility of multi-point injection for tracer tests. Several years of research make them suitable for quantitative transport analysis and flow boundary delineation in both surface and ground waters, including karst, fractured and porous media aquifers. This article presents the effective application of bacteriophages based on their use in differing Swiss hydrological environments and compares their behaviour to conventional coloured dye or salt-type tracers. In surface water and karst aquifers, bacteriophages travel at about the same speed as the typically referenced fluorescent tracers (uranine, sulphurhodamine G extra). In aquifers of interstitial porosity, however, they appear to migrate more rapidly than fluorescent tracers, albeit with a significant reduction in their numbers within the porous media. This faster travel time implies that a modified rationale is needed for defining some ground water protection area boundaries. Further developments of other bacteriophages and their documentation as tracer methods should result in an accurate and efficient tracer tool that will be a proven alternative to conventional fluorescent dyes.

  13. Passive heating of the ground surface

    Science.gov (United States)

    Tyburczyk, Anna

    2016-03-01

    The phenomenon of phase change is one of the most important contemporary issues of thermal engineering. In particular, this applies to all kinds of heat exchanger systems, which should achieve the highest possible efficiency while reducing investment and operating costs. Some of these systems are heat pipes or thermosyphons, which, among others, are used for the heat transfer, temperature stabilization and the regulation of heat flux density. Additionally, they are passive systems, and therefore do not require an external power supply. Heat pipes can be used to stabilize the surface temperature of roads and driveways. Large heat tubes can be applied for heating the surface of bridges and overpasses, which become icy in unfavorable climatic conditions. The paper presents research on the test facility, whose main component is a long vertical copper fin. The temperature at the base of the fin was kept constant for a given series of measurements. Heat receiving fluid was ethanol at atmospheric pressure. The measurement methodology and the results of investigations were discussed. The surface temperature distribution was measured with the infrared camera, and on this basis the local values of heat flow and the heat transfer coefficient were determined. The results were presented as boiling curves for both the fin with the smooth surface and the one covered with a metal capillary-porous structure. The results obtained are useful in the design of heat exchangers, including passive heating of the ground.

  14. Passive heating of the ground surface

    Directory of Open Access Journals (Sweden)

    Tyburczyk Anna

    2016-01-01

    Full Text Available The phenomenon of phase change is one of the most important contemporary issues of thermal engineering. In particular, this applies to all kinds of heat exchanger systems, which should achieve the highest possible efficiency while reducing investment and operating costs. Some of these systems are heat pipes or thermosyphons, which, among others, are used for the heat transfer, temperature stabilization and the regulation of heat flux density. Additionally, they are passive systems, and therefore do not require an external power supply. Heat pipes can be used to stabilize the surface temperature of roads and driveways. Large heat tubes can be applied for heating the surface of bridges and overpasses, which become icy in unfavorable climatic conditions. The paper presents research on the test facility, whose main component is a long vertical copper fin. The temperature at the base of the fin was kept constant for a given series of measurements. Heat receiving fluid was ethanol at atmospheric pressure. The measurement methodology and the results of investigations were discussed. The surface temperature distribution was measured with the infrared camera, and on this basis the local values of heat flow and the heat transfer coefficient were determined. The results were presented as boiling curves for both the fin with the smooth surface and the one covered with a metal capillary-porous structure. The results obtained are useful in the design of heat exchangers, including passive heating of the ground.

  15. Ground-borne vibrations due to dynamic loadings from moving trains in subway tunnels

    Institute of Scientific and Technical Information of China (English)

    Xue-cheng BIAN; Wan-feng JIN; Hong-guang JIANG

    2012-01-01

    In this study,ground vibrations due to dynamic loadings from trains moving in subway tunnels were investigated using a 2.5D finite element model of an underground tunnel and surrounding soil interactions.In our model,wave propagation in the infinitely extended ground is dealt with using a simple,yet efficient gradually damped artificial boundary.Based on the assumption of invariant geometry and material distribution in the tunnel's direction,the Fourier transform of the spatial dimension in this direction is applied to represent the waves in terms of the wave-number.Finite element discretization is employed in the cross-section perpendicular to the tunnel direction and the governing equations are solved for every discrete wave-number.The 3D ground responses are calculated from the wave-number expansion by employing the inverse Fourier transform.The accuracy of the proposed analysis method is verified by a semi-analytical solution of a rectangular load moving inside a soil stratum.A case study of subway train induced ground vibration is presented and the dependency of wave attenuation at the ground surface on the vibration frequency of the moving load is discussed.

  16. Climatic change due to land surface alterations

    Energy Technology Data Exchange (ETDEWEB)

    Franchito, S.H.; Rao, V.B.

    1992-01-01

    A primitive equations global zonally averaged climate model is developed. The model includes biofeedback mechanisms. For the Northern Hemisphere the parameterization of biofeedback mechanisms is similar to that used by Gutman et al. For the Southern Hemisphere new parameterizations are derived. The model simulates reasonably well the mean annual zonally averaged climate and geobotanic zones. Deforestation, desertification, and irrigation experiments are performed. In the case of deforestation and desertification there is a reduction in the surface net radiation, evaporation, and precipitation and an increase in the surface temperature. In the case of irrigation experiment opposite changes occurred. In all the cases considered the changes in evapotranspiration overcome the effect of surface albedo modification. In all the experiments changes are smaller in the Southern Hemisphere.

  17. Ground Surface Deformations Near a Fault-Bounded Groundwater Aquifer

    Science.gov (United States)

    Lipovsky, B.; Funning, G. J.; Ferretti, A.

    2011-12-01

    Geodetic data often reveal the presence of groundwater aquifers that are bounded by faults (Schmidt and Bürgmann, 2003; Galloway and Hoffmann, 2007; Bell et al., 2008). Whereas unrestricted groundwater aquifers exhibit a radially symmetric pattern of uplift with diffuse boundaries, aquifers that are bounded by faults have one or more sharp, linear boundaries. Interferometric synthetic aperture (InSAR) data, due to their high spatial density, are particularly well suited to observe fault bounded aquifers, and the Santa Clara Aquifer in the San Francisco Bay Area, California, constitutes an excellent example. The largest ground surface displacements in the Bay Area are due to the inflation of the Santa Clara aquifer, and InSAR data plainly show that the Santa Clara aquifer is partitioned by the Silver Creek fault. This study first develops a general model of the displacements at the surface of the Earth due to fluid diffusion through a buried permeable boundary such as a fault zone. This model is compared to InSAR data from the Silver Creek fault and we find that we are able to infer fault zone poromechanical properties from InSAR data that are comparable to in situ measurements. Our theoretical model is constrained by several geological and hydrological observations concerning the structure of fault zones. Analytical solutions are presented for the ground surface displacements due to a perfectly impermeable fault zone. This end-member family of models, however, does not fit the available data. We therefore make allowance for an arbitrarily layered, variably permeable, one-dimensional fault zone. Time-dependent ground surface deformations are calculated in the Laplace domain using an efficient semi-analytic method. This general model is applicable to other poroelastic regimes including geothermal and hydrocarbon systems. We are able to estimate fault zone hydraulic conductivity by comparing theoretical ground surface displacements in a permeable fault zone to

  18. Nonlinear Site Response Due to Large Ground Acceleration: Observation and Computer Simulation

    Science.gov (United States)

    Noguchi, S.; Furumura, T.; Sasatani, T.

    2009-12-01

    We studied nonlinear site response due to large ground acceleration during the 2003 off-Miyagi Earthquake (Mw7.0) in Japan by means of horizontal-to-vertical spectral ratio analysis of S-wave motion. The results were then confirmed by finite-difference method (FDM) simulation of nonlinear seismic wave propagation. A nonlinear site response is often observed at soft sediment sites, and even at hard bedrock sites which are covered by thin soil layers. Nonlinear site response can be induced by strong ground motion whose peak ground acceleration (PGA) exceeds about 100 cm/s/s, and seriously affects the amplification of high frequency ground motion and PGA. Noguchi and Sasatani (2008) developed an efficient technique for quantitative evaluation of nonlinear site response using the horizontal-to-vertical spectral ratio of S-wave (S-H/V) derived from strong ground motion records, based on Wen et al. (2006). We applied this technique to perform a detailed analysis of the properties of nonlinear site response based on a large amount of data recorded at 132 K-NET and KiK-net strong motion stations in Northern Japan during the off-Miyagi Earthquake. We succeeded in demonstrating a relationship between ground motion level, nonlinear site response and surface soil characteristics. For example, the seismic data recorded at KiK-net IWTH26 showed obvious characteristics of nonlinear site response when the PGA exceeded 100 cm/s/s. As the ground motion level increased, the dominant peak of S-H/V shifted to lower frequency, the high frequency level of S-H/V dropped, and PGA amplification decreased. On the other hand, the records at MYGH03 seemed not to be affected by nonlinear site response even for high ground motion levels in which PGA exceeds 800 cm/s/s. The characteristics of such nonlinear site amplification can be modeled by evaluating Murnaghan constants (e.g. McCall, 1994), which are the third-order elastic constants. In order to explain the observed characteristics of

  19. Prediction of ground surface displacement caused by grouting

    Institute of Scientific and Technical Information of China (English)

    郭风琪; 刘晓潭; 童无期; 单智

    2015-01-01

    Ground surface displacement caused by grouting was calculated with stochastic medium theory. Ground surface displacement was assumed to be caused by the cavity expansion of grouting, slurry seepage, and slurry contraction. A prediction method of ground surface displacement was developed. The reliability of the presented method was validated through a comparison between theoretical results and results from engineering practice. Results show that the present method is effective. The effect of parameters on uplift displacement was illustrated under different grouting conditions. Through analysis, it can be known that the ground surface uplift is mainly caused by osmosis of slurry and the primary influence angle of stratum βdetermines the influence range of surface uplift. Besides, the results show that ground surface uplift displacement decreases notably with increasing depth of the grouting cavity but it increases with increasing diffusion radius of grout and increasing grouting pressure.

  20. Insulator Surface Flashover Due to UV Illumination

    Energy Technology Data Exchange (ETDEWEB)

    Javedani, J B; Houck, T L; Lahowe, D A; Vogtlin, G E; Goerz, D A

    2009-07-27

    The surface of an insulator under vacuum and under electrical charge will flashover when illuminated by a critical dose of ultra-violet (UV) radiation - depending on the insulator size and material, insulator cone angle, the applied voltage and insulator shot-history. A testbed comprised of an excimer laser (KrF, 248 nm, {approx}16 MW, 30 ns FWHM,), a vacuum chamber, and a negative polarity dc high voltage power supply ({le} -60 kV) were assembled to test 1.0 cm thick angled insulators for surface-flashover. Several candidate insulator materials, e.g. High Density Polyethylene (HDPE), Rexolite{reg_sign} 1400, Macor{trademark} and Mycalex, of varying cone angles were tested against UV illumination. Commercial energy meters were used to measure the UV fluence of the pulsed laser beam. In-house designed and fabricated capacitive probes (D-dots, >12 GHz bandwidth) were embedded in the anode electrode underneath the insulator to determine the time of UV arrival and time of flashover. Of the tested insulators, the +45 degree Rexolite insulator showed more resistance to UV for surface flashover; at UV fluence level of less than 13 mJ/cm{sup 2}, it was not possible to induce a flashover for up to -60 kV of DC potential across the insulator's surface. The probes also permitted the electrical charge on the insulator before and after flashover to be inferred. Photon to electron conversion efficiency for the surface of Rexolite insulator was determined from charge-balance equation. In order to understand the physical mechanism leading to flashover, we further experimented with the +45 degree Rexolite insulator by masking portions of the UV beam to illuminate only a section of the insulator surface; (1) the half nearest the cathode and subsequently, (2) the half nearest the anode. The critical UV fluence and time to flashover were measured and the results in each case were then compared with the base case of full-beam illumination. It was discovered that the time for the

  1. Definition of the risk grounding fatalities due to unintentional airplane crashes by calculates

    Directory of Open Access Journals (Sweden)

    І.Л. Государська

    2005-04-01

    Full Text Available  Estimates of the expected number of grounding fatalities, are given which probably will arise due to accident of air carriers, air taxi and general aviation. Measures regulation of the risk is considered.

  2. Impedance of Surface Footings on Layered Ground

    DEFF Research Database (Denmark)

    Andersen, Lars; Clausen, Johan Christian

    2005-01-01

    Traditionally only the static bearing capacity and stiffness of the ground is considered in the design of wind turbine foundations. However, modern wind turbines are flexible structures with resonance frequencies as low as 0.2 Hz. Unfortunately, environmental loads and the passage of blades past...... the tower may lead to excitation with frequencies of the same order of magnitude. Therefore, dynamic soil-structure interaction has to be accounted for in order to get an accurate prediction of the structural response. In this paper the particular problem of a rigid foundation on a layered subsoil...

  3. Impedance of Surface Footings on Layered Ground

    DEFF Research Database (Denmark)

    Andersen, Lars; Clausen, Johan

    2007-01-01

    Traditionally only the static bearing capacity and stiffness of the ground is considered in the design of wind turbine foundations. However, modern wind turbines are flexible structures with resonance frequencies as low as 0.2 Hz. Unfortunately, environmental loads and the passage of blades past...... the tower may lead to excitation with frequencies of the same order of magnitude. Therefore, dynamic soilstructure interaction has to be accounted for in order to get an accurate prediction of the structural response. In this paper the particular problem of a rigid foundation on a layered subsoil...

  4. Polyfluorinated chemicals in European surface waters, ground- and drinking waters

    NARCIS (Netherlands)

    Eschauzier, C.; de Voogt, P.; Brauch, H.-J.; Lange, F.T.; Knepper, T.P.; Lange, F.T.

    2012-01-01

    Polyfluorinated chemicals (PFCs), especially short chain fluorinated alkyl sulfonates and carboxylates, are ubiquitously found in the environment. This chapter aims at giving an overview of PFC concentrations found in European surface, ground- and drinking waters and their behavior during convention

  5. Polyfluorinated chemicals in European surface waters, ground- and drinking waters

    NARCIS (Netherlands)

    Eschauzier, C.; de Voogt, P.; Brauch, H.-J.; Lange, F.T.; Knepper, T.P.; Lange, F.T.

    2012-01-01

    Polyfluorinated chemicals (PFCs), especially short chain fluorinated alkyl sulfonates and carboxylates, are ubiquitously found in the environment. This chapter aims at giving an overview of PFC concentrations found in European surface, ground- and drinking waters and their behavior during

  6. Digital Modeling Phenomenon Of Surface Ground Movement

    Directory of Open Access Journals (Sweden)

    Ioan Voina

    2016-11-01

    Full Text Available With the development of specialized software applications it was possible to approach and resolve complex problems concerning automating and process optimization for which are being used field data. Computerized representation of the shape and dimensions of the Earth requires a detailed mathematical modeling, known as "digital terrain model". The paper aims to present the digital terrain model of Vulcan mining, Hunedoara County, Romania. Modeling consists of a set of mathematical equations that define in detail the surface of Earth and has an approximate surface rigorously and mathematical, that calculated the land area. Therefore, the digital terrain model means a digital representation of the earth's surface through a mathematical model that approximates the land surface modeling, which can be used in various civil and industrial applications in. To achieve the digital terrain model of data recorded using linear and nonlinear interpolation method based on point survey which highlights the natural surface studied. Given the complexity of this work it is absolutely necessary to know in detail of all topographic elements of work area, without the actions to be undertaken to project and manipulate would not be possible. To achieve digital terrain model, within a specialized software were set appropriate parameters required to achieve this case study. After performing all steps we obtained digital terrain model of Vulcan Mine. Digital terrain model is the complex product, which has characteristics that are equivalent to the specialists that use satellite images and information stored in a digital model, this is easier to use.

  7. Evaluation of ground stiffness parameters using continuous surface wave geophysics

    DEFF Research Database (Denmark)

    Gordon, Anne; Foged, Niels

    2000-01-01

    -small-strain stiffness of the ground Gmax. Continuous surface wave geophysics offers a quick, non-intrusive and economical way of making such measurements. This paper reviews the continuous surface wave techniques and evaluates, in engineering terms, the applicability of the method to the site investigation industry....

  8. Evaluation of ground stiffness parameters using continuous surface wave geophysics

    DEFF Research Database (Denmark)

    Gordon, Anne; Foged, Niels

    2000-01-01

    -small-strain stiffness of the ground Gmax. Continuous surface wave geophysics offers a quick, non-intrusive and economical way of making such measurements. This paper reviews the continuous surface wave techniques and evaluates, in engineering terms, the applicability of the method to the site investigation industry....

  9. Power productivity of the ground surface

    Directory of Open Access Journals (Sweden)

    Gutu A.I.

    2008-12-01

    Full Text Available Here there is presented an attempt to estimate the efficiency degree when working with soil surface through the different methods of valorization incident solar radiation. Such technical methods are being analyzed as (solar collectors, photovoltaic cells, solar thermal power plants, power cultures field (bushes, wheat, sunflower, maize, rape, sorghum as well as microalgae crops. Here is the description of advantages and disadvantages for each group in part out of these three. The technical methods are up to date from the efficiency utilization view-point of industrial area. Microalgae crops are similar to technical methods from this point of view.

  10. Shallow Alluvial Aquifer Ground Water System and Surface Water/Ground Water Interaction, Boulder Creek, Boulder, Colorado

    Science.gov (United States)

    Babcock, K. P.; Ge, S.; Crifasi, R. R.

    2006-12-01

    Water chemistry in Boulder Creek, Colorado, shows significant variation as the Creek flows through the City of Boulder [Barber et al., 2006]. This variation is partially due to ground water inputs, which are not quantitatively understood. The purpose of this study is (1) to understand ground water movement in a shallow alluvial aquifer system and (2) to assess surface water/ground water interaction. The study area, encompassing an area of 1 mi2, is located at the Sawhill and Walden Ponds area in Boulder. This area was reclaimed by the City of Boulder and Boulder County after gravel mining operations ceased in the 1970's. Consequently, ground water has filled in the numerous gravel pits allowing riparian vegetation regrowth and replanting. An integrated approach is used to examine the shallow ground water and surface water of the study area through field measurements, water table mapping, graphical data analysis, and numerical modeling. Collected field data suggest that lateral heterogeneity exists throughout the unconsolidated sediment. Alluvial hydraulic conductivities range from 1 to 24 ft/day and flow rates range from 0.01 to 2 ft/day. Preliminary data analysis suggests that ground water movement parallels surface topography and does not noticeably vary with season. Recharge via infiltrating precipitation is dependent on evapotranspiration (ET) demands and is influenced by preferential flow paths. During the growing season when ET demand exceeds precipitation rates, there is little recharge; however recharge occurs during cooler months when ET demand is insignificant. Preliminary data suggest that the Boulder Creek is gaining ground water as it traverses the study area. Stream flow influences the water table for distances up to 400 feet. The influence of stream flow is reflected in the zones relatively low total dissolved solids concentration. A modeling study is being conducted to synthesize aquifer test data, ground water levels, and stream flow data. The

  11. Uranium in US surface, ground, and domestic waters. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

    1981-04-01

    The report Uranium in US Surface, Ground, and Domestic Waters comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium conentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

  12. The Effect of Images on Surface Potential and Resistance Calculation of Grounding Systems

    Directory of Open Access Journals (Sweden)

    MARTINS, A.

    2015-05-01

    Full Text Available In the grounding systems with a two layers soil, the calculation of the surface potential using the image method is sometimes impossible due to singularities, avoiding researchers to use the method for electrodes in the bottom layer. In the literature this problem solution is refereed as unreliable or solved with other more complex methods. This paper presents a new approach to calculate the surface potentials in a two. layer soil, for electrodes in the bottom layer, when images are at surface. The singularities in computing surface voltage, when the first image upwards lies at surface, are analysed and it's shown that a small change in top layer thickness allows an approximate solution. Surface potentials due to grid conductor are also considered and the values of resistance are compared with those from other methodologies. Singularities for a ground rod that crosses the two layers are also treated. The obtained values of resistance are not satisfactory, due to lower segments images that overlap the upper segments. This paper also proposes shifting the surface of the upper part of the ground rod, in the upper layer, or taking the modulus of the mutual resistance, to overcome this difficulty.

  13. North American regional climate reconstruction from ground surface temperature histories

    Science.gov (United States)

    Jaume-Santero, Fernando; Pickler, Carolyne; Beltrami, Hugo; Mareschal, Jean-Claude

    2016-12-01

    Within the framework of the PAGES NAm2k project, 510 North American borehole temperature-depth profiles were analyzed to infer recent climate changes. To facilitate comparisons and to study the same time period, the profiles were truncated at 300 m. Ground surface temperature histories for the last 500 years were obtained for a model describing temperature changes at the surface for several climate-differentiated regions in North America. The evaluation of the model is done by inversion of temperature perturbations using singular value decomposition and its solutions are assessed using a Monte Carlo approach. The results within 95 % confidence interval suggest a warming between 1.0 and 2.5 K during the last two centuries. A regional analysis, composed of mean temperature changes over the last 500 years and geographical maps of ground surface temperatures, show that all regions experienced warming, but this warming is not spatially uniform and is more marked in northern regions.

  14. Ground-based measurement of surface temperature and thermal emissivity

    Science.gov (United States)

    Owe, M.; Van De Griend, A. A.

    1994-01-01

    Motorized cable systems for transporting infrared thermometers have been used successfully during several international field campaigns. Systems may be configured with as many as four thermal sensors up to 9 m above the surface, and traverse a 30 m transect. Ground and canopy temperatures are important for solving the surface energy balance. The spatial variability of surface temperature is often great, so that averaged point measurements result in highly inaccurate areal estimates. The cable systems are ideal for quantifying both temporal and spatial variabilities. Thermal emissivity is also necessary for deriving the absolute physical temperature, and measurements may be made with a portable measuring box.

  15. A model of the ground surface temperature for micrometeorological analysis

    Science.gov (United States)

    Leaf, Julian S.; Erell, Evyatar

    2017-07-01

    Micrometeorological models at various scales require ground surface temperature, which may not always be measured in sufficient spatial or temporal detail. There is thus a need for a model that can calculate the surface temperature using only widely available weather data, thermal properties of the ground, and surface properties. The vegetated/permeable surface energy balance (VP-SEB) model introduced here requires no a priori knowledge of soil temperature or moisture at any depth. It combines a two-layer characterization of the soil column following the heat conservation law with a sinusoidal function to estimate deep soil temperature, and a simplified procedure for calculating moisture content. A physically based solution is used for each of the energy balance components allowing VP-SEB to be highly portable. VP-SEB was tested using field data measuring bare loess desert soil in dry weather and following rain events. Modeled hourly surface temperature correlated well with the measured data (r 2 = 0.95 for a whole year), with a root-mean-square error of 2.77 K. The model was used to generate input for a pedestrian thermal comfort study using the Index of Thermal Stress (ITS). The simulation shows that the thermal stress on a pedestrian standing in the sun on a fully paved surface, which may be over 500 W on a warm summer day, may be as much as 100 W lower on a grass surface exposed to the same meteorological conditions.

  16. Mitigating ground vibration by periodic inclusions and surface structures

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard; Bucinskas, Paulius; Persson, Peter

    2016-01-01

    -dimensional finite-element model. The laboratory model employs soaked mattress foam placed within a box to mimic a finite volume of soil. The dynamic properties of the soaked foam ensure wavelengths representative of ground vibration in small scale. Comparison of the results from the two models leads......Ground vibration from traffic is a source of nuisance in urbanized areas. Trenches and wave barriers can provide mitigation of vibrations, but single barriers need to have a large depth to be effective-especially in the low-frequency range relevant to traffic-induced vibration. Alternatively...... well-defined behavior can be expected for transient loads and finite structures. However, some mitigation may occur. The paper aims at quantifying the mitigation effect of nearly periodic masses placed on the ground surface using two approaches: a small-scale laboratory model and a three...

  17. Adhesion between silica surfaces due to hydrogen bonding

    Science.gov (United States)

    Bowen, James; Rossetto, Hebert L.; Kendall, Kevin

    2016-09-01

    The adhesion between surfaces can be enhanced significantly by the presence of hydrogen bonding. Confined water at the nanoscale can display behaviour remarkably different to bulk water due to the formation of hydrogen bonds between two surfaces. In this work we investigate the role of confined water on the interaction between hydrophilic surfaces, specifically the effect of organic contaminants in the aqueous phase, by measuring the peak adhesive force and the work of adhesion. Atomic force microscope cantilevers presenting hemispherical silica tips were interacted with planar single crystals of silica in the presence of dimethylformamide, ethanol, and formamide; solution compositions in the range 0-100 mol% water were investigated for each molecule. Each molecule was chosen for its ability to hydrogen bond with water molecules, with increasing concentrations likely to disrupt the structure of surface-bound water layers. With the exception of aqueous solutions containing low concentrations of ethanol, all molecules decreased the ability of confined water to enhance the adhesion between the silica surfaces in excess of the predicted theoretical adhesion due to van der Waals forces. The conclusion was that adhesion depends strongly on the formation of a hydrogen-bonding network within the water layers confined between the silica surfaces.

  18. Assessment of radar interferometry performance for ground subsidence monitoring due to underground mining

    Energy Technology Data Exchange (ETDEWEB)

    Ng, A.H.M.; Chang, H.C.; Ge, L.L.; Rizos, C.; Omura, M. [Cooperative Research Centre for Spatial Information, Carlton, Vic. (Australia)

    2009-07-01

    This paper describes the results from the recently launched SAR satellites for the purpose of subsidence monitoring over underground coal mine sites in the state of New South Wales, Australia, using differential interferometric synthetic aperture radar (DInSAR) technique. The quality of the mine subsidence monitoring results is mainly constrained by noise due to the spatial and temporal decorrelation between the interferometric pair and the phase discontinuities in the interferogram. This paper reports oil the analysis of the impact of these two factors on the performance of DInSAR for monitoring ground deformation. Simulations were carried out prior to real data analyses. SAR data acquired using different operating frequencies, for example, X-, C- and L-band, from the TerraSAR-X, ERS-1/2, ENVISAT, JERS-1 and ALOS satellite missions, were examined. The simulation results showed that the new satellites ALOS, TerraSAR-X and COSMO-SkyMed perform much better than the satellites launched before 2006. ALOS and ENVISAT satellite SAR images with similar temporal coverage were searched for the test site. The ALOS PALSAR DInSAR results have been compared to DInSAR results obtained from ENVISAT ASAR data to investigate the performance of both satellites for ground subsidence monitoring. Strong phase discontinuities and decorrelation have been observed in almost all ENVISAT interferograms and hence it is not possible to generate the displacement maps without errors. However these problems are minimal in ALOS PALSAR interferograms due to its spatial resolution and longer wavelength. Hence ALOS PALSAR is preferred for ground subsidence monitoring in areas covered by vegetation and where there is a high rate ground deformation.

  19. Investigation of differential surface removal due to electropolishing at JLab

    Energy Technology Data Exchange (ETDEWEB)

    Marhauser, Frank [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Folkie, James [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Reece, Charles [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    Surface chemistry carried out for Superconducting Radio Frequency (SRF) cavities such as Buffered Chemical Polishing (BCP) and Electropolishing (EP) aims to uniformly remove the internal surface of a cavity along the entire structure and within each cell from equator to iris in order to obtain an equally etched surface. A uniform removal, however, is not readily achievable due to the complex fluid flow and varying temperatures of the acid mixture, which can lead to differential etching. This needs to be considered when envisaging a certain surface damage removal throughout the interior. The process-specific differential etching influences the target frequency set at the manufacturing stage as well as the field flatness and length of the as-built cavity. We report on analyses of JLab's present EP system using experimental data for six nine-cell cavities that have been processed recently in the frame of the LCLS-II high-Q development plan. In conjunction with numerical simulations, the differential etching and the impact on field flatness is assessed.

  20. Effect of the overconsolidation ratio of soils in surface settlements due to tunneling

    Institute of Scientific and Technical Information of China (English)

    Ludmila Strokova

    2013-01-01

    Construction of urban tunnels requires the control of surface subsidence to minimize any disturbance to nearby buildings and services. Past study of surface subsidence has been limited to mainly empirical solutions based on field studies, and very few analytical studies have been carried out. The available analytical solutions are not sufficient to include complex ground conditions;hence, a comprehensive analytical solution coupled with numerical modeling is necessary to model the effect of surface subsidence due to tunneling. This paper presents the results of modeling of surface settlements due to tunneling using the finite element method. The effect of the overconsolidation ratio of soils expressed in terms of the co-efficient of earth pressure at rest (K0) on surface subsidence due to tunneling is investigated. It is demonstrated that surface settlements appear to be sensitive to K0 values, and for geotechnical calculations pertaining to overconsolidated sand and clay soil, K0 values of 0.6 and 0.8, respectively, are proposed.

  1. Potential Energy Surfaces of Nitrogen Dioxide for the Ground State

    Institute of Scientific and Technical Information of China (English)

    SHAO Ju-Xiang; ZHU Zheng-He; CHENG Xin-Lu; YANG Xiang-Dong

    2007-01-01

    The potential energy function of nitrogen dioxide with the C2v symmetry in the ground state is represented using the simplified Sorbie-Murrell many-body expansion function in terms of the symmetry of NO2. Using the potential energy function, some potential energy surfaces of NO2(C2v, X2A1), such as the bond stretching contour plot for a fixed equilibrium geometry angle θ and contour for O moving around N-O (R1), in which R1 is fixed at the equilibrium bond length, are depicted. The potential energy surfaces are analysed. Moreover, the equilibrium parameters for NO2 with the C2v, Cs and D8h symmetries, such as equilibrium geometry structures and energies, are calculated by the ab initio (CBS-Q) method.

  2. Boussinesq modeling of surface waves due to underwater landslides

    Directory of Open Access Journals (Sweden)

    D. Dutykh

    2013-05-01

    Full Text Available Consideration is given to the influence of an underwater landslide on waves at the surface of a shallow body of fluid. The equations of motion that govern the evolution of the barycenter of the landslide mass include various dissipative effects due to bottom friction, internal energy dissipation, and viscous drag. The surface waves are studied in the Boussinesq scaling, with time-dependent bathymetry. A numerical model for the Boussinesq equations is introduced that is able to handle time-dependent bottom topography, and the equations of motion for the landslide and surface waves are solved simultaneously. The numerical solver for the Boussinesq equations can also be restricted to implement a shallow-water solver, and the shallow-water and Boussinesq configurations are compared. A particular bathymetry is chosen to illustrate the general method, and it is found that the Boussinesq system predicts larger wave run-up than the shallow-water theory in the example treated in this paper. It is also found that the finite fluid domain has a significant impact on the behavior of the wave run-up.

  3. Boussinesq modeling of surface waves due to underwater landslides

    CERN Document Server

    Dutykh, Denys

    2013-01-01

    Consideration is given to the influence of an underwater landslide on waves at the surface of a shallow body of fluid. The equations of motion which govern the evolution of the barycenter of the landslide mass include various dissipative effects due to bottom friction, internal energy dissipation, and viscous drag. The surface waves are studied in the Boussinesq scaling, with time-dependent bathymetry. A numerical model for the Boussinesq equations is introduced which is able to handle time-dependent bottom topography, and the equations of motion for the landslide and surface waves are solved simultaneously. The numerical solver for the Boussinesq equations can also be restricted to implement a shallow-water solver, and the shallow-water and Boussinesq configurations are compared. A particular bathymetry is chosen to illustrate the general method, and it is found that the Boussinesq system predicts larger wave run-up than the shallow-water theory in the example treated in this paper. It also found that the fi...

  4. Laws and mechanisms of slope movement due to shallowly buried coal seam mining under ground gully

    Institute of Scientific and Technical Information of China (English)

    FAN Gang-wei; ZHANG Dong-sheng; ZHAI De-yuan; WANG Xu-feng; LU Xin

    2009-01-01

    Based on the results of similar material simulation, the laws of slope movement due to mining under a gully were analyzed. Selected a slope rock as objective, the mechanisms of slope movement influence upon underground mining were proposed, and respective structural models were built by means of numerical modeling and physical simulation. It holds the point that the influence of slope movement on underground mining could be controlled to some extent by appropriate measures. The results indicate that, for gully-ward mining, which mines toward a gully, the slope rock slides horizontally and rotates in layers; for gully-away mining, which mines away from the gully, the slope rock rotates in a reversed polygon. The slope movement associated with mining under a gully is attributed to pre-existing free faces in the ground gully and underground mining-induced free faces.

  5. Computational dosimetry for grounded and ungrounded human models due to contact current

    Science.gov (United States)

    Chan, Kwok Hung; Hattori, Junya; Laakso, Ilkka; Hirata, Akimasa; Taki, Masao

    2013-08-01

    This study presents the computational dosimetry of contact currents for grounded and ungrounded human models. The uncertainty of the quasi-static (QS) approximation of the in situ electric field induced in a grounded/ungrounded human body due to the contact current is first estimated. Different scenarios of cylindrical and anatomical human body models are considered, and the results are compared with the full-wave analysis. In the QS analysis, the induced field in the grounded cylindrical model is calculated by the QS finite-difference time-domain (QS-FDTD) method, and compared with the analytical solution. Because no analytical solution is available for the grounded/ungrounded anatomical human body model, the results of the QS-FDTD method are then compared with those of the conventional FDTD method. The upper frequency limit for the QS approximation in the contact current dosimetry is found to be 3 MHz, with a relative local error of less than 10%. The error increases above this frequency, which can be attributed to the neglect of the displacement current. The QS or conventional FDTD method is used for the dosimetry of induced electric field and/or specific absorption rate (SAR) for a contact current injected into the index finger of a human body model in the frequency range from 10 Hz to 100 MHz. The in situ electric fields or SAR are compared with the basic restrictions in the international guidelines/standards. The maximum electric field or the 99th percentile value of the electric fields appear not only in the fat and muscle tissues of the finger, but also around the wrist, forearm, and the upper arm. Some discrepancies are observed between the basic restrictions for the electric field and SAR and the reference levels for the contact current, especially in the extremities. These discrepancies are shown by an equation that relates the current density, tissue conductivity, and induced electric field in the finger with a cross-sectional area of 1 cm2.

  6. Diurnal freeze/thaw cycles of the ground surface on the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    YANG MeiXue; YAO TanDong; GOU XiaoHua; HIROSE Nozomu; FUJII Hide Yuki; HAO LiSheng; D.F.LEVIA

    2007-01-01

    The exchange of energy and water between the lithosphere and atmosphere mainly takes place at the ground surface. Therefore, freeze/thaw condition at the ground surface is an important factor in examining the interactions between the land surface and atmosphere. Based on the observation data obtained by CEOP/CAMP-Tibet, the diurnal freeze/thaw cycles of the ground surface near Naqu, central Tibetan Plateau was preliminarily analyzed. The results show that the surface layer was completely frozen for approximately one month. However, the time that the ground surface experienced diurnal freeze/thaw cycles was about 6 months. The high frequency of freeze/thaw cycles at the ground surface significantly influences water and energy exchanges between ground and atmosphere over half a year. The interaction processes between the ground and atmosphere under different soil conditions (such as complete thaw, complete freeze and diurnal freeze/thaw cycles) are issues worthy of further examination.

  7. Parametric studies with an atmospheric diffusion model that assesses toxic fuel hazards due to the ground clouds generated by rocket launches

    Science.gov (United States)

    Stewart, R. B.; Grose, W. L.

    1975-01-01

    Parametric studies were made with a multilayer atmospheric diffusion model to place quantitative limits on the uncertainty of predicting ground-level toxic rocket-fuel concentrations. Exhaust distributions in the ground cloud, cloud stabilized geometry, atmospheric coefficients, the effects of exhaust plume afterburning of carbon monoxide CO, assumed surface mixing-layer division in the model, and model sensitivity to different meteorological regimes were studied. Large-scale differences in ground-level predictions are quantitatively described. Cloud alongwind growth for several meteorological conditions is shown to be in error because of incorrect application of previous diffusion theory. In addition, rocket-plume calculations indicate that almost all of the rocket-motor carbon monoxide is afterburned to carbon dioxide CO2, thus reducing toxic hazards due to CO. The afterburning is also shown to have a significant effect on cloud stabilization height and on ground-level concentrations of exhaust products.

  8. Contamination of ground water, surface water, and soil, and evaluation of selected ground-water pumping alternatives in the Canal Creek area of Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Lorah, Michelle M.; Clark, Jeffrey S.

    1996-01-01

    Chemical manufacturing, munitions filling, and other military-support activities have resulted in the contamination of ground water, surface water, and soil in the Canal Creek area of Aberdeen Proving Ground, Maryland. Chlorinated volatile organic compounds, including 1,1,2,2-tetrachloroethane and trichloroethylene, are widespread ground-water contaminants in two aquifers that are composed of unconsolidated sand and gravel. Distribution and fate of chlorinated organic compounds in the ground water has been affected by the movement and dissolution of solvents in their dense immiscible phase and by microbial degradation under anaerobic conditions. Detection of volatile organic contaminants in adjacent surface water indicates that shallow contaminated ground water discharges to surface water. Semivolatile organic compounds, especially polycyclic aromatic hydrocarbons, are the most prevalent organic contaminants in soils. Various trace elements, such as arsenic, cadmium, lead, and zinc, were found in elevated concentrations in ground water, surface water, and soil. Simulations with a ground-water-flow model and particle tracker postprocessor show that, without remedial pumpage, the contaminants will eventually migrate to Canal Creek and Gunpowder River. Simulations indicate that remedial pumpage of 2.0 million gallons per day from existing wells is needed to capture all particles originating in the contaminant plumes. Simulated pumpage from offsite wells screened in a lower confined aquifer does not affect the flow of contaminated ground water in the Canal Creek area.

  9. Interannual changes in snow cover and its impact on ground surface temperatures in Livingston Island (Antarctica)

    Science.gov (United States)

    Nieuwendam, Alexandre; Ramos, Miguel; Vieira, Gonçalo

    2015-04-01

    In permafrost areas the seasonal snow cover is an important factor on the ground thermal regime. Snow depth and timing are important in ground insulation from the atmosphere, creating different snow patterns and resulting in spatially variable ground temperatures. The aim of this work is to characterize the interactions between ground thermal regimes and snow cover and the influence on permafrost spatial distribution. The study area is the ice-free terrains of northwestern Hurd Peninsula in the vicinity of the Spanish Antarctic Station "Juan Carlos I" and Bulgarian Antarctic Station "St. Kliment Ohridski". Air and ground temperatures and snow thickness data where analysed from 4 sites along an altitudinal transect in Hurd Peninsula from 2007 to 2012: Nuevo Incinerador (25 m asl), Collado Ramos (110 m), Ohridski (140 m) and Reina Sofia Peak (275 m). The data covers 6 cold seasons showing different conditions: i) very cold with thin snow cover; ii) cold with a gradual increase of snow cover; iii) warm with thick snow cover. The data shows three types of periods regarding the ground surface thermal regime and the thickness of snow cover: a) thin snow cover and short-term fluctuation of ground temperatures; b) thick snow cover and stable ground temperatures; c) very thick snow cover and ground temperatures nearly constant at 0°C. a) Thin snow cover periods: Collado Ramos and Ohridski sites show frequent temperature variations, alternating between short-term fluctuations and stable ground temperatures. Nuevo Incinerador displays during most of the winter stable ground temperatures; b) Cold winters with a gradual increase of the snow cover: Nuevo Incinerador, Collado Ramos and Ohridski sites show similar behavior, with a long period of stable ground temperatures; c) Thick snow cover periods: Collado Ramos and Ohridski show long periods of stable ground, while Nuevo Incinerador shows temperatures close to 0°C since the beginning of the winter, due to early snow cover

  10. Impact of caprock permeability on vertical ground surface displacements in geological underground utilisation

    Science.gov (United States)

    Kempka, Thomas; Tillner, Elena

    2015-04-01

    Geological underground utilisation inducing pore pressure changes in underground reservoirs is generally accompanied by hydro-mechanical processes. Thereby, pore pressure increase due to fluid injection may trigger ground surface uplift, while a decrease in pore pressure due to reservoir fluid production is known to induce ground subsidence. Different coupled hydro-mechanical simulation studies (e.g. Klimkowski et al., 2015, Kempka et al., 2014, Tillner et al., 2014) indicate that ground surface displacements can achieve a magnitude of several decimetres, if storage or production operations are being carried out at an industrial scale. Consequently, detailed knowledge on the parameters impacting ground surface uplift or subsidence is of major interest for the success of any geological underground utilisation in order to avoid surface infrastructure damage by spatially varying deformations. Furthermore, ground subsidence may result increased groundwater levels as experienced in different underground coal mining districts. In the present study, we carried out coupled hydro-mechanical simulations to account for the impact of caprock permeability on ground surface displacements resulting from geological underground utilisation. Thereto, different simulation scenarios were investigated using a synthetic 3D coupled numerical simulation model with varying caprock permeability and vertical location of the open well section in the target reservoir. Material property ranges were derived from available literature, while a normal faulting stress state was applied in all simulation scenarios. Our simulation results demonstrate that caprock permeability has a significant impact on the pressure development, and thus on vertical displacements at the ground surface as well as at the reservoir top. An increase in caprock permeability from 1 x 10-20 m2 by two orders of magnitude doubles vertical displacements at the ground surface, whereas vertical displacements at the reservoir top

  11. A preliminary study on surface ground deformation near shallow foundation induced by strike-slip faulting

    Science.gov (United States)

    Wong, Pei-Syuan; Lin, Ming-Lang

    2016-04-01

    According to investigation of recent earthquakes, ground deformation and surface rupture are used to map the influenced range of the active fault. The zones of horizontal and vertical surface displacements and different features of surface rupture are investigated in the field, for example, the Greendale Fault 2010, MW 7.1 Canterbury earthquake. The buildings near the fault rotated and displaced vertically and horizontally due to the ground deformation. Besides, the propagation of fault trace detoured them because of the higher rigidity. Consequently, it's necessary to explore the ground deformation and mechanism of the foundation induced by strike-slip faulting for the safety issue. Based on previous study from scaled analogue model of strike-slip faulting, the ground deformation is controlled by material properties, depth of soil, and boundary condition. On the condition controlled, the model shows the features of ground deformation in the field. This study presents results from shear box experiment on small-scale soft clay models subjected to strike-slip faulting and placed shallow foundations on it in a 1-g environment. The quantifiable data including sequence of surface rupture, topography and the position of foundation are recorded with increasing faulting. From the result of the experiment, first en echelon R shears appeared. The R shears rotated to a more parallel angle to the trace and cracks pulled apart along them with increasing displacements. Then the P shears crossed the basement fault in the opposite direction appears and linked R shears. Lastly the central shear was Y shears. On the other hand, the development of wider zones of rupture, higher rising surface and larger the crack area on surface developed, with deeper depth of soil. With the depth of 1 cm and half-box displacement 1.2 cm, en echelon R shears appeared and the surface above the fault trace elevated to 1.15 mm (Dv), causing a 1.16 cm-wide zone of ground-surface rupture and deformation

  12. SHAPE BIFURCATION OF AN ELASTIC WAFER DUE TO SURFACE STRESS

    Institute of Scientific and Technical Information of China (English)

    闫琨; 何陵辉; 刘人怀

    2003-01-01

    A geometrically nonlinear analysis was proposed for the deformation of a freestanding elastically isotropic wafer caused by the surface stress change on one surface. Thelink between the curvature and the change in surface stress was obtained analytically fromenergetic consideration. In contrast to the existing linear analysis, a remarkableconsequence is that, when the wafer is very thin or the surface stress difference between thetwo major surfaces is large enough, the shape of the wafer will bifurcate.

  13. Model for ground motion and atmospheric overpressure due to underground nuclear explosion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.; Walker, J.J.

    1980-10-01

    A physical model is proposed to describe the ground motion pattern resulting from an underground nulear explosion in an idealized homogeneous medium. Irregular behaviors in the observed ground motion are assumed to be perturbations caused by the local inhomogeneity of the ground medium. Our model correlates the ground motions at any point in the spalled zone to the initial acceleration pulse at the ground zero. Interestingly, the model predicts that the ground motion first comes to a stop at a definite radius about the ground zero, and the region expands both outward and inward as time goes on. We believe that this result is closely related to a phenomenon observed at NTS. In the far field approximation, we also calculate the overpressure in the lower atmosphere generated by the ground motion. We demonstrate that the irregular component of the ground motion does not affect the overpressure history in any significant way. Consequently the model ground motion can be used as a good approximation in generating the atmospheric overpressure.

  14. GROUND SURFACE VISUALIZATION USING RED RELIEF IMAGE MAP FOR A VARIETY OF MAP SCALES

    Directory of Open Access Journals (Sweden)

    T. Chiba

    2016-06-01

    Full Text Available There are many methods to express topographical features of ground surface. In which, contour map has been the traditional method and along with development of digital data, surface model such as shaded relief map has been using for ground surface expression. Recently, data acquisition has been developed very much quick, demanding more advanced visualization method to express ground surface so as to effectively use the high quality data. In this study, the authors using the Red Relief Image Map (RRIM, Chiba et al., 2008 to express ground surface visualization for a variety of map scales. The authors used 30 m mesh data of SRTM to show the topographical features of western Mongolian and micro-topographical features of ground surface in tectonically active regions of Japan. The results show that, compared to traditional and other similar methods, the RRIM can express ground surface more precisely and 3-dimensionally, suggested its advanced usage for many fields of topographical visualization.

  15. Ground Surface Visualization Using Red Relief Image Map for a Variety of Map Scales

    Science.gov (United States)

    Chiba, T.; Hasi, B.

    2016-06-01

    There are many methods to express topographical features of ground surface. In which, contour map has been the traditional method and along with development of digital data, surface model such as shaded relief map has been using for ground surface expression. Recently, data acquisition has been developed very much quick, demanding more advanced visualization method to express ground surface so as to effectively use the high quality data. In this study, the authors using the Red Relief Image Map (RRIM, Chiba et al., 2008) to express ground surface visualization for a variety of map scales. The authors used 30 m mesh data of SRTM to show the topographical features of western Mongolian and micro-topographical features of ground surface in tectonically active regions of Japan. The results show that, compared to traditional and other similar methods, the RRIM can express ground surface more precisely and 3-dimensionally, suggested its advanced usage for many fields of topographical visualization.

  16. Locally controlled globally smooth ground surface reconstruction from terrestrial point clouds

    CERN Document Server

    Rychkov, Igor

    2012-01-01

    Approaches to ground surface reconstruction from massive terrestrial point clouds are presented. Using a set of local least squares (LSQR) planes, the "holes" are filled either from the ground model of the next coarser level or by Hermite Radial Basis Functions (HRBF). Global curvature continuous as well as infinitely smooth ground surface models are obtained with Partition of Unity (PU) using either tensor product B-Splines or compactly supported exponential function. The resulting surface function has local control enabling fast evaluation.

  17. Accumulation of Microswimmers due to Their Collisions with a Surface

    CERN Document Server

    Li, Guanglai

    2008-01-01

    In this letter we propose a kinematic model to show how collisions with a surface and rotational Brownian motion give rise to the accumulation of micro-swimmers near a surface. In this model, an elongated microswimmer invariably travels parallel to the surface after hitting it from any incident angle. It then swims away from the surface after some time, facilitated by rotational Brownian motion. Simulations based on this model reproduce the density distributions measured for the small bacteria E. coli and Caulobacter crescentus, as well as for the much larger bull spermatozoa swimming in confinement.

  18. Using ground data of the Global Terrestrial Network of Permafrost (GTN-P) for the evaluation of ESA Data User Element (DUE) Permafrost remote sensing derived products

    Science.gov (United States)

    Elger, K.; Heim, B.; Bartsch, A.; Paulik, Ch.; Duguay, C.; Hachem, S.; Soliman, A.; Boike, J.; Langer, M.; Lantuit, H.

    2012-04-01

    Permafrost is one of the essential climate variables addressed by the Global Terrestrial Observing System (GCOS). Remote sensing data provide area-wide monitoring of e.g. surface temperatures or soil surface status (frozen or thawed state) in the Arctic and Subarctic, where ground data collection is difficult and restricted to local measurements at few monitoring sites. The task of the ESA Data User Element (DUE) Permafrost project is to build-up an Earth observation service for northern high-latitudinal permafrost applications with extensive involvement of the international permafrost research community (www.ipf.tuwien.ac.at/permafrost). The satellite-derived DUE Permafrost products are Land Surface Temperature, Surface Soil Moisture, Surface Frozen and Thawed State, Digital Elevation Model (locally as remote sensing product and circumpolar as non-remote sensing product) and Subsidence, and Land Cover. Land Surface Temperature, Surface Soil Moisture, and Surface Frozen and Thawed State will be provided for the circumpolar permafrost area north of 55° N with 25 km spatial resolution. In addition, regional products with higher spatial resolution were developed for five case study regions in different permafrost zones of the tundra and taiga (Laptev Sea [RU], Central Yakutia [RU], Western Siberia [RU], Alaska N-S transect, [US] Mackenzie River and Valley [CA]). This study shows the evaluation of two DUE Permafrost regional products, Land Surface Temperature and Surface Frozen and Thawed State, using freely available ground truth data from the Global Terrestrial Network of Permafrost (GTN-P) and monitoring data from the Russian-German Samoylov research station in the Lena River Delta (Central Siberia, RU). The GTN-P permafrost monitoring sites with their position in different permafrost zones are highly qualified for the validation of DUE Permafrost remote sensing products. Air and surface temperatures with high-temporal resolution from eleven GTN-P sites in Alaska

  19. Prediction of ground vibration due to the collapse of a 235 m high cooling tower under accidental loads

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Feng; Li, Yi [Department of Building Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China); Gu, Xianglin, E-mail: gxl@tongji.edu.cn [Department of Building Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China); Zhao, Xinyuan [Department of Building Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China); Tang, Dongsheng [Guangdong Electric Power Design Institute, No. 1 Tianfeng Road, Guangzhou, Guangdong 510663 (China)

    2013-05-15

    Highlights: ► Ground vibration due to the collapse of a huge cooling tower was predicted. ► Accidental loads with different characteristics caused different collapse modes. ► Effect of ground vibration on the nuclear-related facilities cannot be ignored. -- Abstract: A comprehensive approach is presented in this study for the prediction of the ground vibration due to the collapse of a 235 m high cooling tower, which can be caused by various accidental loads, e.g., explosion or strong wind. The predicted ground motion is to be used in the safety evaluation of nuclear-related facilities adjacent to the cooling tower, as well as the plant planning of a nuclear power station to be constructed in China. Firstly, falling weight tests were conducted at a construction site using the dynamic compaction method. The ground vibrations were measured in the form of acceleration time history. A finite element method based “falling weight-soil” model was then developed and verified by field test results. Meanwhile, the simulated collapse processes of the cooling tower under two accidental loads were completed in a parallel study, the results of which are briefly introduced in this paper. Furthermore, based on the “falling weight-soil” model, “cooling tower-soil” models were developed for the prediction of the ground vibrations induced by two collapse modes of the cooling tower. Finally, for a deep understanding of the vibration characteristics, a parametric study was also conducted with consideration of different collapse profiles, soil geologies as well as the arrangements of an isolation trench. It was found that severe ground vibration occurred in the vicinity of the cooling tower when the collapse happened. However, the vibration attenuated rapidly with the increase in distance from the cooling tower. Moreover, the “collapse in integrity” mode and the rock foundation contributed to exciting intense ground vibration. By appropriately arranging an isolation

  20. Measured ground-surface movements, Cerro Prieto geothermal field

    Energy Technology Data Exchange (ETDEWEB)

    Massey, B.L.

    1981-01-01

    The Cerro Prieto geothermal area in the Mexicali Valley, 30 kilometers southeast of Mexicali, Baja California, incurred slight deformation because of the extraction of hot water and steam, and probably, active tectonism. During 1977 to 1978, the US Geological Survey established and measured two networks of horizontal control in an effort to define both types of movement. These networks consisted of: (1) a regional trilateration net brought into the mountain ranges west of the geothermal area from stations on an existing US Geological Survey crustal-strain network north of the international border; and (2) a local net tied to stations in the regional net and encompassing the present and planned geothermal production area. Electronic distance measuring instruments were used to measure the distances between stations in both networks in 1978, 1979 and 1981. Lines in the regional net averaged 25 km. in length and the standard deviation of an individual measurement is estimated to be approx. 0.3 part per million of line length. The local network was measured using different instrumentation and techniques. The average line length was about 5 km. and the standard deviation of an individual measurement approached 3 parts per million per line length. Ground-surface movements in the regional net, as measured by both the 1979 and 1981 resurveys, were small and did not exceed the noise level. The 1979 resurvey of the local net showed an apparent movement of 2 to 3 centimeters inward toward the center of the production area. This apparent movement was restricted to the general limits of the production area. The 1981 resurvey of the local net did not show increased movement attributable to fluid extraction.

  1. Enhanced diffusion due to active swimmers at a solid surface

    CERN Document Server

    Miño, Gaston; Darnige, Thierry; Hoyos, Mauricio; Dauchet, Jeremy; Dunstan, Jocelyn; Soto, Rodrigo; Wang, Yang; Rousselet, Annie; Clement, Eric

    2010-01-01

    We consider two systems of active swimmers moving close to a solid surface, one being a living population of wild-type \\textit{E. coli} and the other being an assembly of self-propelled Au-Pt rods. In both situations, we have identified two different types of motion at the surface and evaluated the fraction of the population that displayed ballistic trajectories (active swimmers) with respect to those showing random-like behavior. We studied the effect of this complex swimming activity on the diffusivity of passive tracers also present at the surface. We found that the tracer diffusivity is enhanced with respect to standard Brownian motion and increases linearly with the activity of the fluid, defined as the product of the fraction of active swimmers and their mean velocity. This result can be understood in terms of series of elementary encounters between the active swimmers and the tracers.

  2. INVESTIGATION OF PROCESS PERTAINING TO INTERACTION OF TRACTOR DRIVING WHEELS WITH GROUND SURFACE

    Directory of Open Access Journals (Sweden)

    V. V. Guskov

    2017-01-01

    Full Text Available The paper presents results of investigations on the process pertaining to interaction of a driving wheel with ground surface and describes methodology for optimization of backbone parameters. The mentioned process has some specific differences in comparison with the process of wheel rolling along hard surface. Ground surface is represented by mixture of sandy and clay particles with plant residues and it has a number of physical and mechanical properties. The main of these properties is resistance of soil against compression and displacement. Compression process determines a track depth and resistance to motion and displacement process determines wheel gripping property and its tangential traction force. While executing the investigations laws of compression and displacement proposed by Prof.V. V. Katsygin as the most adequate reflection of actual processes have been used in the paper. Motion of the driving wheel along ground surface is accompanied by its slipping. It has been determined that the maximum wheel traction force is formed not with 100% slipping as it was supposed until present but the value has been obtained at 45–60 % slipping according to soil category. The developed integral equations with due account of the aspect make it possible to calculate road hold characteristics of driving wheels of the designed wheel tractor and evaluate its traction, speed and economic characteristics. Methodology has been developed for optimization of backbone parameters of wheeled running gear in the designed tractor such as design mass and adhesion weight, width, diameter and air pressure in a tire. The proposed methodology has been introduced in designing practice of wheeled tractors at OJSC “Minsk Tractor Works”.

  3. Vertical Crustal Displacements Due to Surface Fluid Changes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shiyu; ZHONG Min

    2007-01-01

    Using the model data for surface mass changes of the atmosphere, ocean, soil moisture and snow depth, the vertical crustal displacements of 25 ficual stations in China were calculated according to the loading theory. From the spectral analysis of the results, we can see that the periods of displacements are 12 months and the semi-periods are 6 months. The results also show that the maximum seasonal displacements can reach 20 mm and even larger. The covariance analyses and significance tests show that the coefficients of 96 percent of the stations are significant at the 0.1 significance level. The results show that one of the reasons of the vertical crustal displacements is the changing surface fluid loads.

  4. Measurement of Mode Interaction Due to Waveguide Surface Roughness.

    Science.gov (United States)

    1984-12-01

    Speed of Mode 1 over Wedge Roughness at 7813 Hz Due to Cycle Error q. 104 q cprI (mis) Cr r 100M% -2 335.33 6.94 -1 346.16 3.93 0 357.73 0.72 1370.07...4.4 Mode 2 Energy Attenuation Freq (Hz) Smooth (dB/m) Rough (dB/m) 7750 2.0 4.8 15750 2.8 10.5 23500 3.5 12.2 31250 4.3 10.1 110 c -c q CprI (m/s) .pr... cprI x 100(%)C pr -1 377.30 1.86 0 398.58 -3.68 Table 35. Change in Phase Speed of Mode I over Random Roughness at 7750 Hz Due to Cycle Error q. 124

  5. Dynamic Performance on Multi Storey Structure Due to Ground Borne Vibrations Input from Passing Vehicles

    Directory of Open Access Journals (Sweden)

    Tuan Norhayati Tuan Chik

    2013-12-01

    Full Text Available Ground borne vibration from passing vehicles could excite the adjacent ground, hence produces a vibration waves that will propagate through layers of soil towards the foundations of any adjacent building. This vibration could affects the structure of the building at some levels and even the low sensitivity equipment are also could be affected as well. The objectives of this study are to perform the structural response on multi storey building subjected to ground vibrations input and to determine the level of vibration at each floor from road traffic on the observed building. The scopes of the study are focused on the groundborne vibrations induced by the passing vehicles and analyse the data by using dynamic software such as ANSYSv14 and MATLAB. The selected building for this study is the Registrar Office building which is located in Universiti Tun Hussein Onn Malaysia (UTHM. The inputs of the vibration were measured by using Laser Doppler Vibrometer (LDV equipment. By conducting the field measurement, a real input of ground borne vibration from the loads of vehicle towards any adjacent building can be obtained. Finally, the vibration level from road traffic on office building can be determined using overseas generic criteria guidelines. The vibration level achieved for this building is at above the ISO level, which is suitable for office building and within acceptable limit.

  6. Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears

    Science.gov (United States)

    Townsend, Dennis P.; Patel, P. R.

    1988-01-01

    Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

  7. Ground-state charge transfer as a mechanism for surface-enhanced Raman scattering

    Science.gov (United States)

    Lippitsch, Max E.

    1984-03-01

    A model is presented for the contribution of ground-state charge transfer between a metal and adsorbate to surface-enhanced Raman scattering (SERS). It is shown that this contribution can be understood using the vibronic theory for calculating Raman intensities. The enhancement is due to vibronic coupling of the molecular ground state to the metal states, the coupling mechanism being a modulation of the ground-state charge-transfer energy by the molecular vibrations. An analysis of the coupling operator gives the selection rules for this process, which turn out to be dependent on the overall symmetry of the adsorbate-metal system, even if the charge transfer is small enough for the symmetry of the adsorbate to remain the same as that of the free molecule. It is shown that the model can yield predictions on the properties of SERS, e.g., specificity to adsorption geometry, appearance of forbidden bands, dependence on the applied potential, and dependence on the excitation wavelength. The predictions are in good agreement with experimental results. It is also deduced from this model that in many cases atomic-scale roughness is a prerequisite for the observation of SERS. A result on the magnitude of the enhancement can only be given in a crude approximation. Although in most cases an additional electromagnetic enhancement seems to be necessary to give an observable signal, this charge-transfer mechanism should be important in many SERS systems.

  8. Lower ground state due to counter-rotating wave interaction in trapped ion system

    CERN Document Server

    Liu, T; Feng, M

    2007-01-01

    We consider a single ion confined in a trap under radiation of two traveling waves of lasers. In the strong-excitation regime and without the restriction of Lamb-Dicke limit, the Hamiltonian of the system is similar to a driving Jaynes-Cummings model without rotating wave approximation (RWA). The approach we developed enables us to present a complete eigensolutions, which makes it available to compare with the solutions under the RWA. We find that, the ground state in our non-RWA solution is energically lower than the counterpart under the RWA. If we have the ion in the ground state, it is equivalent to a spin dependent force on the trapped ion. Discussion is made for the difference between the solutions with and without the RWA, and for the relevant experimental test, as well as for the possible application in quantum information processing.

  9. Ground vibrations due to pile and sheet pile driving : prediction models of today

    OpenAIRE

    Deckner, Fanny; Viking, Kenneth; Hintze, Staffan

    2012-01-01

    As part of aconstruction work pile and sheet pile driving unavoidably generates vibrations.As of today construction works are often located in urban areas and along withsociety’s increasing concern of environmental impact the need for vibrationprediction prior to construction is of immediate interest. This study presents a review of the predictionmodels existing today. For prediction of ground vibrations from pile and sheetpile driving there are roughly three different types of models; empiri...

  10. Monitoring ground subsidence due to underground mining using integrated space geodetic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Linlin Ge; Michael Hsing-Chung Chang; Chris Rizos [University of NSW, NSW (Australia)

    2004-04-01

    Differential radar interferometry (DInSAR) can deliver {approximately} 1cm height change resolution. The combination of regular radar beam scanning and movement of the satellites carrying the radar sensor enables imaging of the mining region in seconds, from which subtle ground movements can be detected. Quantitative validation comparing the DInSAR-derived subsidence profile against ground truth shows a best RMS error of 1.4cm. A methodology has been developed to use GPS (the Global Positioning System) observations to measure atmospheric disturbances so that the DInSAR results can be corrected. A Geographic Information System (GIS) has been used to post-process InSAR results throughout this project. GIS can be used to present the final results in various formats, for example, profiles for validating with ground truth, subsidence contour maps, and three-dimensional views. Professional looking thematic maps can be generated based on these analyses, lining up with the practice within the mining industry to deliver drawings/maps in a GIS format. Multi-temporal DInSAR results can be analysed using GIS, and the final results compiled into an animation, showing the subsidence region moving as time passes. A virtual reality image has been generated in the GIS, combining DEM, aerial photography, and DInSAR subsidence results. The UNSW InSAR-GPS-GIS Integration Software has been developed to support the seamless flow of data among the three technologies, DInSAR, GPS, and GIS. Several radar satellite missions, some especially designed for InSAR, are scheduled for launch in the near future. Therefore radar data of global coverage with weekly or even daily revisit will be made available at multiple radar bands. With atmospheric disturbances properly accounted for, DInSAR will be a cost-effective, reliable, and operational tool that complements traditional ground survey methods.

  11. Limitation of Ground-based Estimates of Solar Irradiance Due to Atmospheric Variations

    Science.gov (United States)

    Wen, Guoyong; Cahalan, Robert F.; Holben, Brent N.

    2003-01-01

    The uncertainty in ground-based estimates of solar irradiance is quantitatively related to the temporal variability of the atmosphere's optical thickness. The upper and lower bounds of the accuracy of estimates using the Langley Plot technique are proportional to the standard deviation of aerosol optical thickness (approx. +/- 13 sigma(delta tau)). The estimates of spectral solar irradiance (SSI) in two Cimel sun photometer channels from the Mauna Loa site of AERONET are compared with satellite observations from SOLSTICE (Solar Stellar Irradiance Comparison Experiment) on UARS (Upper Atmospheric Research Satellite) for almost two years of data. The true solar variations related to the 27-day solar rotation cycle observed from SOLSTICE are about 0.15% at the two sun photometer channels. The variability in ground-based estimates is statistically one order of magnitude larger. Even though about 30% of these estimates from all Level 2.0 Cimel data fall within the 0.4 to approx. 0.5% variation level, ground-based estimates are not able to capture the 27-day solar variation observed from SOLSTICE.

  12. Surface and borehole ground-penetrating-radar developments

    NARCIS (Netherlands)

    Slob, E.C.; Sato, M.; Olhoeft, G.

    2010-01-01

    During the past 80 years, ground-penetrating radar (GPR) has evolved from a skeptically received glacier sounder to a full multicomponent 3D volume-imaging and characterization device. The tool can be calibrated to allow for quantitative estimates of physical properties such as water content. Becau

  13. Mitigating ground vibration by periodic inclusions and surface structures

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard; Bucinskas, Paulius; Persson, Peter

    2016-01-01

    Ground vibration from traffic is a source of nuisance in urbanized areas. Trenches and wave barriers can provide mitigation of vibrations, but single barriers need to have a large depth to be effective-especially in the low-frequency range relevant to traffic-induced vibration. Alternatively, per...

  14. Near-ground cooling efficacies of trees and high-albedo surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, R M [Univ. of California, Berkeley, CA (United States). Dept. of Mechanical Engineering

    1997-05-01

    Daytime summer urban heat islands arise when the prevalence of dark-colored surfaces and lack of vegetation make a city warmer than neighboring countryside. Two frequently-proposed summer heat island mitigation measures are to plant trees and to increase the albedo (solar reflectivity) of ground surfaces. This dissertation examines the effects of these measures on the surface temperature of an object near the ground, and on solar heating of air near the ground. Near-ground objects include people, vehicles, and buildings. The variation of the surface temperature of a near-ground object with ground albedo indicates that a rise in ground albedo will cool a near-ground object only if the object`s albedo exceeds a critical value. This critical value of object albedo depends on wind speed, object geometry, and the height of the atmospheric thermal boundary layer. It ranges from 0.15 to 0.37 for a person. If an object has typical albedo of 0.3, increasing the ground albedo by.

  15. Topographical Anisotropy and Wetting of Ground Stainless Steel Surfaces

    Directory of Open Access Journals (Sweden)

    Cornelia Bellmann

    2012-12-01

    Full Text Available Microscopic and physico-chemical methods were used for a comprehensive surface characterization of different mechanically modified stainless steel surfaces. The surfaces were analyzed using high-resolution confocal microscopy, resulting in detailed information about the topographic properties. In addition, static water contact angle measurements were carried out to characterize the surface heterogeneity of the samples. The effect of morphological anisotropy on water contact angle anisotropy was investigated. The correlation between topography and wetting was studied by means of a model of wetting proposed in the present work, that allows quantifying the air volume of the interface water drop-stainless steel surface.

  16. The influence of faulting on ground movement due to coalmining: the UK and European experience

    Energy Technology Data Exchange (ETDEWEB)

    Heltewell, E.G.

    1988-01-01

    It has been recognised from the time of the earliest investigations into coal mining subsidence that geological faults can play a significant role in determining the nature of ground movement resulting from coal extraction. However, the limited research undertaken on this aspect has been spasmodic yet wide ranging and has resulted in the findings being published in diverse sources. The paper summarises the evidence and conclusions of observers in the UK and Europe and therefore reveals the present state of knowledge in this aspect of coal mining subsidence. 18 refs., 2 figs.

  17. Concentration distributions of thoron and radon near the ground surface

    Energy Technology Data Exchange (ETDEWEB)

    Katase, Akira [Tohwa Univ., Fukuoka (Japan). Faculty of Engineering

    1996-12-01

    One dimensional diffusion model with a constant diffusion coefficient is applied to the thoron concentration distributions in air above the ground. The experimental distributions are well described by the exponential function obtained from the model. Diffusion coefficients and thoron exhalation rates are estimated from the measured distributions, which are the average values for three months. The present values of thoron exhalation are however several times as small as those measured by other researchers. (author)

  18. Assessment of volatile organic compounds in surface water at West Branch Canal Creek, Aberdeen Proving Ground, Maryland, 1999

    Science.gov (United States)

    Olsen, Lisa D.; Spencer, Tracey A.

    2000-01-01

    The U.S. Geological Survey (USGS) collected 13 surface-water samples and 3 replicates from 5 sites in the West Branch Canal Creek area at Aberdeen Proving Ground from February through August 1999, as a part of an investigation of ground-water contamination and natural attenuation processes. The samples were analyzed for volatile organic compounds, including trichloroethylene, 1,1,2,2-tetrachloroethane, carbon tetrachloride, and chloroform, which are the four major contaminants that were detected in ground water in the Canal Creek area in earlier USGS studies. Field blanks were collected during the sampling period to assess sample bias. Field replicates were used to assess sample variability, which was expressed as relative percent difference. The mean variability of the surface-water replicate analyses was larger (35.4 percent) than the mean variability of ground-water replicate analyses (14.6 percent) determined for West Branch Canal Creek from 1995 through 1996. The higher variability in surface-water analyses is probably due to heterogeneities in the composition of the surface water rather than differences in sampling or analytical procedures. The most frequently detected volatile organic compound was 1,1,2,2- tetrachloroethane, which was detected in every sample and in two of the replicates. The surface-water contamination is likely the result of cross-media transfer of contaminants from the ground water and sediments along the West Branch Canal Creek. The full extent of surface-water contamination in West Branch Canal Creek and the locations of probable contaminant sources cannot be determined from this limited set of data. Tidal mixing, creek flow patterns, and potential effects of a drought that occurred during the sampling period also complicate the evaluation of surface-water contamination.

  19. Ground effects of space weather investigated by the surface impedance

    Science.gov (United States)

    Pirjola, R.; Boteler, D.; Trichtchenko, L.

    2009-02-01

    The objective of this paper is to provide a discussion of the surface impedance applicable in connection with studies of geomagnetically induced currents (GIC) in technological systems. This viewpoint means that the surface impedance is regarded as a tool to determine the horizontal (geo)electric field at the Earth's surface, which is the key quantity for GIC. Thus the approach is different from the traditional magnetotelluric viewpoint. The definition of the surface impedance usually involves wavenumber-frequency-domain fields, so inverse Fourier transforming the expression of the electric field in terms of the surface impedance and the geomagnetic field results in convolution integrals in the time and space domains. The frequency-dependent surface impedance has a high-pass filter character whereas the corresponding transfer function between the electric field and the time derivative of the magnetic field is of a low-pass filter type. The relative change of the latter transfer function with frequency is usually smaller than that of the surface impedance, which indicates that the geoelectric field is closer to the time derivative than to the magnetic field itself. An investigation of the surface impedance defined by the space-domain electric and magnetic components indicates that the largest electric fields are not always achieved by the plane wave assumption, which is sometimes regarded as an extreme case for GIC. It is also concluded in this paper that it is often possible to apply the plane wave relation locally between the surface electric and magnetic fields. The absolute value of the surface impedance decreases with an increasing wavenumber although the maximum may also be at a non-zero value of the wavenumber. The imaginary part of the surface impedance usually much exceeds the real part.

  20. Analysis on effect of surface fault to site ground motion using finite element method

    Institute of Scientific and Technical Information of China (English)

    曹炳政; 罗奇峰

    2003-01-01

    Dynamic contact theory is applied to simulate the sliding of surface fault. Finite element method is used to analyze the effect of surface fault to site ground motions. Calculated results indicate that amplification effect is obvious in the area near surface fault, especially on the site that is in the downside fault. The results show that the effect of surface fault should be considered when important structure is constructed in the site with surface fault.

  1. National Enforcement Initiative: Preventing Animal Waste from Contaminating Surface and Ground Water

    Science.gov (United States)

    This page describes EPA's goal in preventing animal waste from contaminating surface and ground Water. It is an EPA National Enforcement Initiative. Both enforcement cases, and a map of enforcement actions are provided.

  2. The Simulation of Grinding Wheels and Ground Surface Roughness Based on Virtual Reality Technology

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The paper describes the feasibility and method of the application of virtual reality technology to grinding process, and introduces the modeling method of object entity in the environment of virtual reality. The simulation process of grinding wheels and ground surface roughness is discussed, and the computation program system of numerical simulation is compiled with Visual C++ programming language. At the same time, the three-dimensional simulation models of grinding wheels and ground surface roughness are ...

  3. Uncertainties and shortcomings of ground surface temperature histories derived from inversion of temperature logs

    OpenAIRE

    Hartmann, Andreas; Rath, Volker

    2008-01-01

    Analysing borehole temperature data in terms of ground surface history can add useful information to reconstructions of past climates. Therefore, a rigorous assessment of uncertainties and error sources is a necessary prerequisite for the meaningful interpretation of such ground surface temperature histories. This study analyses the most prominent sources of uncertainty. The diffusive nature of the process makes the inversion relatively robust against incomplete knowledge of the thermal diffu...

  4. Modelling ground rupture due to groundwater withdrawal: applications to test cases in China and Mexico

    Science.gov (United States)

    Franceschini, A.; Teatini, P.; Janna, C.; Ferronato, M.; Gambolati, G.; Ye, S.; Carreón-Freyre, D.

    2015-11-01

    The stress variation induced by aquifer overdraft in sedimentary basins with shallow bedrock may cause rupture in the form of pre-existing fault activation or earth fissure generation. The process is causing major detrimental effects on a many areas in China and Mexico. Ruptures yield discontinuity in both displacement and stress field that classic continuous finite element (FE) models cannot address. Interface finite elements (IE), typically used in contact mechanics, may be of great help and are implemented herein to simulate the fault geomechanical behaviour. Two main approaches, i.e. Penalty and Lagrangian, are developed to enforce the contact condition on the element interface. The incorporation of IE incorporation into a three-dimensional (3-D) FE geomechanical simulator shows that the Lagrangian approach is numerically more robust and stable than the Penalty, thus providing more reliable solutions. Furthermore, the use of a Newton-Raphson scheme to deal with the non-linear elasto-plastic fault behaviour allows for quadratic convergence. The FE - IE model is applied to investigate the likely ground rupture in realistic 3-D geologic settings. The case studies are representative of the City of Wuxi in the Jiangsu Province (China), and of the City of Queretaro, Mexico, where significant land subsidence has been accompanied by the generation of several earth fissures jeopardizing the stability and integrity of the overland structures and infrastructure.

  5. Ground-water and surface-water quality data for the West Branch Canal Creek area, Aberdeen Proving Ground, Maryland

    Science.gov (United States)

    Spencer, Tracey A.; Phelan, Daniel J.; Olsen, Lisa D.; Lorah, Michelle M.

    2001-01-01

    This report presents ground-water and surface-water quality data from samples collected by the U.S. Geological Survey from November 1999 through May 2001 at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The report also provides a description of the sampling and analytical methods that were used to collect and analyze the samples, and includes an evaluation of the quality-assurance data. The ground-water sampling network included two 4-inch wells, two 2-inch wells, sixteen 1-inch piezometers, one hundred thirteen 0.75-inch piezometers, two 0.25-inch flexible-tubing piezo-meters, twenty-seven 0.25-inch piezometers, and forty-two multi-level monitoring system depths at six sites. Ground-water profiler samples were collected from nine sites at 34 depths. In addition, passive-diffusion-bag samplers were deployed at four sites, and porous-membrane sampling devices were installed in the upper sediment at five sites. Surface-water samples were collected from 20 sites. Samples were collected from wells and 0.75-inch piezometers for measurement of field parameters and reduction-oxidation constituents, and analysis of inorganic and organic constituents, during three sampling events in March?April and June?August 2000, and May 2001. Surface-water samples were collected from November 1999 through September 2000 during five sampling events for analysis of organic constituents. Ground-water profiler samples were collected in April?May 2000, and analyzed for field measure-ments, reduction-oxidation constituents, and inorganic constituents and organic constituents. Passive-diffusion-bag samplers were installed in September 2000, and samples were analyzed for organic constituents. Multi-level monitoring system samples were collected and analyzed for field measurements and reduction-oxidation con-stituents, inorganic constituents, and organic con-stituents in March?April and June?August 2000. Field measurements and organic constituents were collected from 0.25-inch

  6. Monitoring surface geothermal features using time series of aerial and ground-based photographs

    Science.gov (United States)

    Bromley, C.; van Manen, S. M.; Graham, D.

    2010-12-01

    Geothermal systems are of high conservation and scientific value and monitoring of these is an important management tool to assess natural variations and changes resulting from development and utilization. This study examines time series of aerial and ground-based photographs of geothermal areas within the Taupo Volcanic Zone, New Zealand. A time series of aerial photographs from 1946-2007 of the Broadlands Road Scenic Reserve (Taupo, New Zealand) highlights large changes to this small area as the result of the start of geothermal fluid production for the nearby Wairakei power plant in 1958 and other causes. Prior to the opening of the plant the area was not geothermally active, but expansion of steam zones due to pressure drawdown has resulted in significant thermal changes in the subsurface. These subsurface thermal changes are evident in the aerial photographs as the appearance of hydrothermal eruption craters and areas of thermal bare ground, which are too hot for vegetation to grown on. In addition, in the late 1960’s thermotolerant vegetation started to establish itself in the adjacent area. Changes in the surface area covered by each of these, reflect changes in the geothermal system as well as changes in management (e.g. exclusion of livestock), and a time series of these changes has been produced using ArcMap™. Monthly photographs of surface geothermal expressions in the Rotorua area show changes in colour and size of chloride springs with time. Colour and size changes are difficult to quantify due to varying exposure settings, weather conditions, and vantage points. However, these qualitative descriptions can be combined with quantitative time series such as temperature measurements, to provide better insight into surface changes that have occurred at this geothermal field. This study highlights the value of both qualitative and quantitative data that can be obtained from time series of photographs, including photographs that were obtained before the

  7. Model experimental research on deformation and subsidence characteristics of ground and wall rock due to mining under thick overlying terrane

    Energy Technology Data Exchange (ETDEWEB)

    Weizhong Ren; Chengmai Guo; Ziqiang Peng; Yonggang Wang [Chinese Academy of Sciences, Wuhan (China). Institute of Rock and Soil Mechanics

    2010-06-15

    Based on the prototype of a mine, a physical simulation test is conducted. The characteristics of the deformation and failure of the ground surface and the wall rock around a goaf, as well as the creep behavior of the wall rock deformation and the failure mechanism, are analyzed. The simulation test has greatly improved our understanding on the wall rock's deformation and failure characteristics. For the first time, digital close-range photogrammetry was used to measure the displacements in a sectional model test. The measurements by this technique agreed very well with those obtained by other methods, such as using dial gauges.

  8. ESA DUE Permafrost: Evaluation of remote sensing derived products using ground data from the Global Terrestrial Network of Permafrost (GTN-P)

    Science.gov (United States)

    Elger, K. K.; Heim, B.; Lantuit, H.; Boike, J.; Bartsch, A.; Paulik, C.; Duguay, C. R.; Hachem, S.; Soliman, A. S.

    2011-12-01

    The task of the ESA DUE Permafrost project is to build up an Earth observation service for high-latitudinal permafrost applications with extensive involvement of the permafrost research community. The DUE Permafrost products derived from remote sensing are land surface temperature (LST), surface soil moisture (SSM), surface frozen and thawed state (freeze/ thaw), terrain, land cover, and surface waters. Weekly and monthly averages for most of the DUE Permafrost products will be made available for the years 2007-2010. The DUE Permafrost products are provided for the circumpolar permafrost area (north of 55°N) with 25 km spatial resolution. In addition, regional products with higher spatial resolution (300-1000 m/ pixel) were developed for five case study regions. These regions are: (1) the Laptev Sea and Eastern Siberian Sea Region (RU, continuous very cold permafrost/ tundra), (2) the Yakutsk Region (RU, continuous cold permafrost/ taiga), (3) the Western Siberian transect including Yamal Peninsula and Ob Region (RU, continuous to discontinuous/ taiga-tundra), (4) the Alaska Highway Transect (US, continuous to discontinuous/ taiga-tundra), and (5) the Mackenzie Delta and Valley Transect (CA, continuous to discontinuous/ taiga-tundra). The challenge of the programme is to adapt remote sensing products that are well established and tested in agricultural low and mid-latitudinal areas for highly heterogeneous taiga/ tundra permafrost landscapes in arctic regions. Ground data is essential for the evaluation of DUE Permafrost products and is provided by user groups and global networks. A major part of the DUE Permafrost core user group is contributing to GTN-P, the Global Terrestrial Network of Permafrost. Its main programmes, the Circumpolar Active Layer Monitoring (CALM) and the Thermal State of Permafrost (TSP) have been thoroughly overhauled during the last International Polar Year (2007-2008). Their spatial coverage has been extended to provide a true circumpolar

  9. Surface roughening of ground fused silica processed by atmospheric inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Xin, Qiang; Li, Na; Wang, Jun; Wang, Bo, E-mail: bradywang@hit.edu.cn; Li, Guo; Ding, Fei; Jin, Huiliang

    2015-06-30

    Highlights: • The morphology evolution of ground fused silica, processed by atmospheric plasma, was investigated experimentally. • The roughness development results from opening and coalescing of the plasma-etched cracks. • The shapes of grain-like etched pits are the results of the adjacent cracks coalescing with one another. • The descent of the pits density is due to some smaller etched pits that are swallowed up by larger pits. • Leading role in surface smoothing is laterally etching away the side walls of the intersecting pits. - Abstract: Subsurface damage (SSD) is a defect that is inevitably induced during mechanical processes, such as grinding and polishing. This defect dramatically reduces the mechanical strength and the laser damage thresholds of optical elements. Compared with traditional mechanical machining, atmospheric pressure plasma processing (APPP) is a relatively novel technology that induces almost no SSD during the processing of silica-based optical materials. In this paper, a form of APPP, inductively coupled plasma (ICP), is used to process fused silica substrates with fluorocarbon precursor under atmospheric pressure. The surface morphology evolution of ICP-processed substrates was observed and characterized by confocal laser scanning microscope (CLSM), field emission scanning electron microscope (SEM), and atomic force microscopy (AFM). The results show that the roughness evolves with the etching depth, and the roughness evolution is a single-peaked curve. This curve results from the opening and the coalescing of surface cracks and fractures. The coalescence procedure of these microstructures was simulated with two common etched pits on a polished fused silica surface. Understanding the roughness evolution of plasma-processed surface might be helpful in optimizing the optical fabrication chain that contains APPP.

  10. Surface water waves due to an oscillatory wavemaker in the presence of surface tension

    Directory of Open Access Journals (Sweden)

    B. N. Mandal

    1992-01-01

    Full Text Available The initial value problem of generation of surface water waves by a harmonically oscillating plane vertical wavemaker in an infinite incompressible fluid under the action of gravity and surface tension is investigated. In the asymptotic evaluation of the free surface depression for large time and distance, the contribution to the integral by stationary phase method gives rise to transient component of the free surface depression while the contribution from the poles give rise to steady state component. It is observed that the presence of surface tension sometimes changes the qualitative nature of the transient component of free surface depression.

  11. Use of chemical and isotopic tracers to characterize the interactions between ground water and surface water in mantled karst

    Science.gov (United States)

    Katz, B.G.; Coplen, T.B.; Bullen, T.D.; Hal, Davis J.

    1997-01-01

    Floridan aquifer, the major processes controlling the concentrations of major dissolved species included dissolution of calcite and dolomite, and degradation of organic matter under oxic conditions. The Upper Floridan aquifer is highly susceptible to contamination from activities at the land surface in the Tallahassee area. The presence of post-1950s concentrations of 3H in ground water from depths greater than 100 m below land surface indicates that water throughout much of the Upper Floridan aquifer has been recharged during the last 40 years. Even though mixing is likely between ground water and surface water in many parts of the study area, the Upper Floridan aquifer produces good quality water, which due to dilution effects shows little if any impact from trace elements or nutrients that are present in surface waters.The water quality of the Upper Floridan aquifer is influenced by the degree of connectivity between the aquifer and the surface water. Chemical and isotopic analyses, tritium, and strontium-87/strontium-86 along with geochemical mass-balance modeling were used to identify the dominant hydrochemical processes that control the composition of groundwater. Differences in the composition of water isotopes in rainfall, groundwater and surface water were used to develop mixing models of surface water and groundwater. Even though mixing is likely between groundwater and surface water in many parts of the study area, the Upper Floridan aquifer produces good quality water, showing little impact from trace elements present in surface waters.

  12. Study on the Surface Free Energy of Ground CaO by IGC

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    CaO formed by decomposing CaCO3 at 1450℃ was ground in a vibrational mill,then the long-time ground sample was reheated at different temperatures.Inverse Gas Chromatography (IGC) was used to measure the variation of the sample′s surface free energy under grinding and reheating.It is concluded that the total surface free energy and the London dispersive component of the surface free energy increases with grinding,while the polar component first increases with grinding,and then decreases,and finally disappears.When the long-time ground sample was reheated,its total surface free energy decreases,among which the London component decreases,but the polar component appears again.

  13. Geologic Evidence for Late-Stage Equatorial Surface and Ground Ice on Mars

    Science.gov (United States)

    Chapman, M. G.

    2003-12-01

    within some ILD mounds. Theatre-headed gullies cut into the flanks of mounds in Hebes, Juventae, Gangis, and Ophir Chasmata. At the MOC scale these gullies display no impact craters and could therefore be extremely young. Finally, one new image attests to possibly recent ground ice within floor material of Juventae Chasma. At the MOC scale, surfaces within this chasma have few impact craters, indicating a very young surface age. MOC image M0804669 shows some interesting geologic/geomorphic relations that occur within the chasma. For instance, on the south side of a chaotic knob, a talus deposit with a flat, possible pediment cap has been cut by late-stage erosion from wind, water, or ice. This relation indicates that relatively steady, talus-forming erosion was interrupted by a period of downcutting that incised the talus and caprock. On the north part of image M08-04669, an impact crater rim and its ejecta blanket are pitted with irregularly shaped depressions that appear similar to terrestrial thermokarst pits found in active glaciated and periglacial terrain due to the meltout of buried ice. The south end of this same image shows possible brittle fracture of channel-confined, dune-covered material. The possible thermokarst pits and brittle fractures may indicate melting of late-stage ground ice. Valles Marineris is a possible volcano-tectonic graben or collapse structure. Dark material within the chasma has been suggested to be very young volcanic material and MOC data appears to show several associated possible volcanic vents. Perhaps late-stage to recent volcanism drove water into the chasma, changed the local atmospheric circulation to create a unique microclimate, and issued forth a fine-grain, protective dust cover of dark ash.

  14. Large-aperture ground glass surface profile measurement using coherence scanning interferometry.

    Science.gov (United States)

    Bae, Eundeok; Kim, Yunseok; Park, Sanguk; Kim, Seung-Woo

    2017-01-23

    We present a coherence scanning interferometer configured to deal with rough glass surfaces exhibiting very low reflectance due to severe sub-surface light scattering. A compound light source is prepared by combining a superluminescent light-emitting diode with an ytterbium-doped fiber amplifier. The light source is attuned to offer a short temporal coherence length of 15 μm but with high spatial coherence to secure an adequate correlogram contrast by delivering strongly unbalanced optical power to the low reflectance target. In addition, the infrared spectral range of the light source is shifted close to the visible side at a 1,038 nm center wavelength, so a digital camera of multi-mega pixels available for industrial machine vision can be used to improve the correlogram contrast further with better lateral image resolutions. Experimental results obtained from a ground Zerodur mirror of 200 mm aperture size and 0.9 μm rms roughness are discussed to validate the proposed interferometer system.

  15. Ground and surface water for drinking: a laboratory study on genotoxicity using plant tests

    Directory of Open Access Journals (Sweden)

    Donatella Feretti

    2012-02-01

    Full Text Available Surface waters are increasingly utilized for drinking water because groundwater sources are often polluted. Several monitoring studies have detected the presence of mutagenicity in drinking water, especially from surface sources due to the reaction of natural organic matter with disinfectant. The study aimed to investigate the genotoxic potential of the products of reaction between humic substances, which are naturally present in surface water, and three disinfectants: chlorine dioxide, sodium hypochlorite and peracetic acid. Commercial humic acids dissolved in distilled water at different total organic carbon (TOC concentrations were studied in order to simulate natural conditions of both ground water (TOC=2.5 mg/L and surface water (TOC=7.5 mg/L. These solutions were treated with the biocides at a 1:1 molar ratio of C:disinfectant and tested for genotoxicity using the anaphase chromosomal aberration and micronucleus tests in Allium cepa, and the Vicia faba and Tradescantia micronucleus tests. The tests were carried out after different times and with different modes of exposure, and at 1:1 and 1:10 dilutions of disinfected and undisinfected humic acid solutions. A genotoxic effect was found for sodium hypochlorite in all plant tests, at both TOCs considered, while chlorine dioxide gave positive results only with the A.cepa tests. Some positive effects were also detected for PAA (A.cepa and Tradescantia. No relevant differences were found in samples with different TOC values. The significant increase in all genotoxicity end-points induced by all tested disinfectants indicates that a genotoxic potential is exerted even in the presence of organic substances at similar concentrations to those frequently present in drinking water.

  16. Ground and surface water for drinking: a laboratory study on genotoxicity using plant tests.

    Science.gov (United States)

    Feretti, Donatella; Ceretti, Elisabetta; Gustavino, Bianca; Zerbini, Llaria; Zani, Claudia; Monarca, Silvano; Rizzoni, Marco

    2012-02-17

    Surface waters are increasingly utilized for drinking water because groundwater sources are often polluted. Several monitoring studies have detected the presence of mutagenicity in drinking water, especially from surface sources due to the reaction of natural organic matter with disinfectant. The study aimed to investigate the genotoxic potential of the products of reaction between humic substances, which are naturally present in surface water, and three disinfectants: chlorine dioxide, sodium hypochlorite and peracetic acid. Commercial humic acids dissolved in distilled water at different total organic carbon (TOC) concentrations were studied in order to simulate natural conditions of both ground water (TOC=2.5 mg/L) and surface water (TOC=7.5 mg/L). These solutions were treated with the biocides at a 1:1 molar ratio of C:disinfectant and tested for genotoxicity using the anaphase chromosomal aberration and micronucleus tests in Allium cepa, and the Vicia faba and Tradescantia micronucleus tests. The tests were carried out after different times and with different modes of exposure, and at 1:1 and 1:10 dilutions of disinfected and undisinfected humic acid solutions. A genotoxic effect was found for sodium hypochlorite in all plant tests, at both TOCs considered, while chlorine dioxide gave positive results only with the A.cepa tests. Some positive effects were also detected for PAA (A.cepa and Tradescantia). No relevant differences were found in samples with different TOC values. The significant increase in all genotoxicity end-points induced by all tested disinfectants indicates that a genotoxic potential is exerted even in the presence of organic substances at similar concentrations to those frequently present in drinking water.

  17. Salmonella pollution in ground and surface waters. (Latest citations from Pollution abstracts). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1993-04-01

    The bibliography contains citations concerning the contamination of ground waters and surface waters by Salmonella bacteria. Articles discuss the occurence, survival, origin, and control of these bacteria in water sources including rivers, reservoirs, swimming pools, wastewater, aquifers, and ground water. Citations also address the use of Salmonella populations as biological indicators of pollution in aquatic systems. (Contains a minimum of 102 citations and includes a subject term index and title list.)

  18. On Ground Surface Extraction Using Full-Waveform Airborne Laser Scanner for Cim

    Science.gov (United States)

    Nakano, K.; Chikatsu, H.

    2015-05-01

    Satellite positioning systems such as GPS and GLONASS have created significant changes not only in terms of spatial information but also in the construction industry. It is possible to execute a suitable construction plan by using a computerized intelligent construction. Therefore, an accurate estimate of the amount of earthwork is important for operating heavy equipment, and measurement of ground surface with high accuracy is required. A full-waveform airborne laser scanner is expected to be capable of improving the accuracy of ground surface extraction for forested areas, in contrast to discrete airborne laser scanners, as technological innovation. For forested areas, fundamental studies for construction information management (CIM) were conducted to extract ground surface using full-waveform airborne laser scanners based on waveform information.

  19. ON GROUND SURFACE EXTRACTION USING FULL-WAVEFORM AIRBORNE LASER SCANNER FOR CIM

    Directory of Open Access Journals (Sweden)

    K. Nakano

    2015-05-01

    Full Text Available Satellite positioning systems such as GPS and GLONASS have created significant changes not only in terms of spatial information but also in the construction industry. It is possible to execute a suitable construction plan by using a computerized intelligent construction. Therefore, an accurate estimate of the amount of earthwork is important for operating heavy equipment, and measurement of ground surface with high accuracy is required. A full-waveform airborne laser scanner is expected to be capable of improving the accuracy of ground surface extraction for forested areas, in contrast to discrete airborne laser scanners, as technological innovation. For forested areas, fundamental studies for construction information management (CIM were conducted to extract ground surface using full-waveform airborne laser scanners based on waveform information.

  20. Damping of an ion acoustic surface wave due to surface currents

    CERN Document Server

    Lee, H J

    1999-01-01

    The well-known linear dispersion relation for an ion acoustic surface wave has been obtained by including the linear surface current density J sub z parallel to the interface and by neglecting the linear surface current density J sub x perpendicular to the interface. The neglect of J sub x is questionable although it leads to the popular boundary condition that the tangential electric field is continuous. In this work, linear dispersion relation for an ion acoustic surface wave is worked out by including both components of the linear current density J . When that is done, the ion acoustic wave turns out to be heavily damped. If the electron mass is taken to be zero (electrons are Bolzmann-distributed), the perpendicular component of the surface current density vanishes, and we have the well-known ion acoustic surface wave eigenmode. We conclude that an ion acoustic surface wave propagates as an eigenmode only when its phase velocity is much smaller than the electron thermal velocity.

  1. Ground surface thermal regime of rock glaciers in the High Tatra Mts., Slovakia

    Science.gov (United States)

    Uxa, Tomáš; Mida, Peter

    2017-04-01

    Numerous lobate- or tongue-shaped debris accumulations, mostly interpreted as rock glaciers, have recently been recognized in the High Tatra Mts., Slovakia (49˚ 10' N, 20˚ 08' E). These prominent landforms arise due to creep of voluminous debris-ice mixtures, and as such they are excellent indicators of present or past permafrost existence. Hence rock glaciers are extensively utilized to model the distribution of permafrost in mountain areas. However, commonly applied rules of thumb may not be entirely indicative to discriminate particularly between the inactive (permafrost in disequilibrium with present climate) and relict (without permafrost) rock glaciers, which may substantially complicate permafrost modelling. Accordingly, the information about their thermal state is essential to calibrate and validate regional permafrost models. Limited ground temperature data have been, however, available from the High Tatra Mts. to date and therefore, we bring the updated and enhanced results from the thermal investigations of eleven rock glaciers located in the Slavkovská dolina and Veľká Studená dolina valleys at elevations between 1832 and 2090 m asl. Ground surface temperature (GST) has been continuously monitored at seven rock glaciers between October 2014 and September 2016 using nine Minikin Tie (EMS Brno Inc.) and iButton DS1922L (Maxim Integrated Inc.) loggers with an accuracy of ±0.2 and ±0.5 ˚ C, respectively. In addition, the bottom temperature of snow (BTS) was measured at 306 locations during spring of 2015 and 2016 to map potential permafrost occurrence within all the surveyed rock glaciers and in their immediate surroundings. Mean annual ground surface temperature (MAGST) of the rock glaciers ranged between -1.3 ˚ C and +2.6 ˚ C and averaged +1.0 ˚ C and +0.8 ˚ C in 2014-2015 and 2015-2016, respectively. Two sites continually showed negative MAGST and two other sites were below +0.5 ˚ C and +1.0 ˚ C, respectively. This strongly contrasts with

  2. Modeling short wave radiation and ground surface temperature: a validation experiment in the Western Alps

    Science.gov (United States)

    Pogliotti, P.; Cremonese, E.; Dallamico, M.; Gruber, S.; Migliavacca, M.; Morra di Cella, U.

    2009-12-01

    Permafrost distribution in high-mountain areas is influenced by topography (micro-climate) and high variability of ground covers conditions. Its monitoring is very difficult due to logistical problems like accessibility, costs, weather conditions and reliability of instrumentation. For these reasons physically-based modeling of surface rock/ground temperatures (GST) is fundamental for the study of mountain permafrost dynamics. With this awareness a 1D version of GEOtop model (www.geotop.org) is tested in several high-mountain sites and its accuracy to reproduce GST and incoming short wave radiation (SWin) is evaluated using independent field measurements. In order to describe the influence of topography, both flat and near-vertical sites with different aspects are considered. Since the validation of SWin is difficult on steep rock faces (due to the lack of direct measures) and validation of GST is difficult on flat sites (due to the presence of snow) the two parameters are validated as independent experiments: SWin only on flat morphologies, GST only on the steep ones. The main purpose is to investigate the effect of: (i) distance between driving meteo station location and simulation point location, (ii) cloudiness, (iii) simulation point aspect, (iv) winter/summer period. The temporal duration of model runs is variable from 3 years for the SWin experiment to 8 years for the validation of GST. The model parameterization is constant and tuned for a common massive bedrock of crystalline rock like granite. Ground temperature profile is not initialized because rock temperature is measured at only 10cm depth. A set of 9 performance measures is used for comparing model predictions and observations (including: fractional mean bias (FB), coefficient of residual mass (CMR), mean absolute error (MAE), modelling efficiency (ME), coefficient of determination (R2)). Results are very encouraging. For both experiments the distance (Km) between location of the driving meteo

  3. Topographical changes of ground surface affected by the Tarim Desert Highway

    Institute of Scientific and Technical Information of China (English)

    LI Shengyu; LEI Jiaqiang; XU Xinwen; WANG Lixin; ZHOU Zhibin; LI Hongzhong

    2006-01-01

    The Tarim Desert Highway is the longest highway crossing the mobile desert in the world. The highway and its sand protection system were established in 1995. This great project must have significant effect on the aeolian environment in its neighborhoods. In 2004, we investigated the topographic changes of ground surface within the sand protection system and its external adjacent area in the hinterland of the Taklimakan Desert. The results showed that (i) the original topographic patterns of ground surface were greatly changed, and erosion as well as deposition was distributed clearly on the ground surface, affected by the road and its sand protection system; (ii) sediment deposited in the sand protection system gradually heightened the ground surface, but each part in the system changed differently: in the sand-blocking belt, a transverse sand ridge was formed in the same direction as the upright sand barrier; in the sand-binding belt, sediment was aggraded on the original surface in a certain thickness; at the initial stages since the establishment of the sand protection system, erosion had taken place in the un-stabilized area named by the deposition belt between the sand-blocking belt and the sand-binding belt, the inner of sand-binding belt, the windward slope of dunes in the sand-binding belt, and the neighboring leeward area of the sand protection system.

  4. MAN-MADE RADIONUCLIDES IN THE NEAR-THE-GROUND ATMOSPHERIC LAYER DUE TO THE FUKUSHIMA ACCIDENT

    Directory of Open Access Journals (Sweden)

    V. G. Bulgakov

    2011-01-01

    Full Text Available The article presents information about the main observation results of radiometric departments of the Federal Service for Hydrometeorology and Environmental Monitoring for changes in the radiation situation on the territory of Russia following the accident at the Fukushima NPP. The obtained experimental data allowed to conclude that the volumetric activities of radionuclides in the near-the-ground  atmospheric layer were by 3 to 6 orders of magnitude below the permissible volumetric activity set by Radiation Safety Standards (NRB-99/2009, and the correction to the density of soil contamination by cesium-137 was by 2 to 3 orders of magnitude less than the decrease of the density of contamination with this isotope of the global origin due to radioactive decay.

  5. Simulation of the Regional Ground-Water-Flow System and Ground-Water/Surface-Water Interaction in the Rock River Basin, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.

    2009-01-01

    A regional, two-dimensional, areal ground-water-flow model was developed to simulate the ground-water-flow system and ground-water/surface-water interaction in the Rock River Basin. The model was developed by the U.S. Geological Survey (USGS), in cooperation with the Rock River Coalition. The objectives of the regional model were to improve understanding of the ground-water-flow system and to develop a tool suitable for evaluating the effects of potential regional water-management programs. The computer code GFLOW was used because of the ease with which the model can simulate ground-water/surface-water interactions, provide a framework for simulating regional ground-water-flow systems, and be refined in a stepwise fashion to incorporate new data and simulate ground-water-flow patterns at multiple scales. The ground-water-flow model described in this report simulates the major hydrogeologic features of the modeled area, including bedrock and surficial aquifers, ground-water/surface-water interactions, and ground-water withdrawals from high-capacity wells. The steady-state model treats the ground-water-flow system as a single layer with hydraulic conductivity and base elevation zones that reflect the distribution of lithologic groups above the Precambrian bedrock and a regionally significant confining unit, the Maquoketa Formation. In the eastern part of the Basin where the shale-rich Maquoketa Formation is present, deep ground-water flow in the sandstone aquifer below the Maquoketa Formation was not simulated directly, but flow into this aquifer was incorporated into the GFLOW model from previous work in southeastern Wisconsin. Recharge was constrained primarily by stream base-flow estimates and was applied uniformly within zones guided by regional infiltration estimates for soils. The model includes average ground-water withdrawals from 1997 to 2006 for municipal wells and from 1997 to 2005 for high-capacity irrigation, industrial, and commercial wells. In addition

  6. Quality factor due to roughness scattering of shear horizontal surface acoustic waves in nanoresonators

    NARCIS (Netherlands)

    Palasantzas, G.

    2008-01-01

    In this work we study the quality factor associated with dissipation due to scattering of shear horizontal surface acoustic waves by random self-affine roughness. It is shown that the quality factor is strongly influenced by both the surface roughness exponent H and the roughness amplitude w to late

  7. Earth modeling and estimation of the local seismic ground motion due to site geology in complex volcanoclastic areas

    Directory of Open Access Journals (Sweden)

    V. Di Fiore

    2002-06-01

    Full Text Available Volcanic areas often show complex behaviour as far as seismic waves propagation and seismic motion at surface are concerned. In fact, the finite lateral extent of surface layers such as lava flows, blocks, differential welding and/or zeolitization within pyroclastic deposits, introduces in the propagation of seismic waves effects such as the generation of surface waves at the edge, resonance in lateral direction, diffractions and scattering of energy, which tend to modify the amplitude as well as the duration of the ground motion. The irregular topographic surface, typical of volcanic areas, also strongly influences the seismic site response. Despite this heterogeneity, it is unfortunately a common geophysical and engineering practice to evaluate even in volcanic environments the subsurface velocity field with monodimensional investigation method (i.e. geognostic soundings, refraction survey, down-hole, etc. prior to the seismic site response computation which in a such cases is obviously also made with 1D algorithms. This approach often leads to highly inaccurate results. In this paper we use a different approach, i.e. a fully 2D P-wave Çturning rayÈ tomographic survey followed by 2D seismic site response modeling. We report here the results of this approach in three sites located at short distance from Mt. Vesuvius and Campi Flegrei and characterized by overburdens constituted by volcanoclastic deposits with large lateral and vertical variations of their elastic properties. Comparison between 1D and 2D Dynamic Amplification Factor shows in all reported cases entirely different results, both in terms of peak period and spectral contents, as expected from the clear bidimensionality of the geological section. Therefore, these studies suggest evaluating carefully the subsoil geological structures in areas characterized by possible large lateral and vertical variations of the elastic properties in order to reach correct seismic site response

  8. Size of craters produced by explosive charges on or above the ground surface

    Science.gov (United States)

    Ambrosini, R. D.; Luccioni, B. M.; Danesi, R. F.; Riera, J. D.; Rocha, M. M.

    The results of a series of tests performed with different amounts of explosive at short distances above and below ground level, as well as on the soil surface are briefly described. After an introductory description of both the main features of the blast wave and the mechanics of crater formation, a brief review of empirical methods for crater size prediction is presented. Next, the experimental design and the results obtained are described. The crater dimensions for underground explosions coincide with those found in the literature. For explosions at ground level the results are qualitatively described by empirical equations. For explosive charges situated above ground level, the dimensions of the craters are smaller than those observed in underground and near the surface explosions. Two new single prediction equations for this case are presented.

  9. Inferring snow pack ripening and melt out from distributed ground surface temperature measurements

    Directory of Open Access Journals (Sweden)

    M.-O. Schmid

    2012-02-01

    Full Text Available The seasonal snow cover and its melting are heterogeneous both in space and time. Describing and modelling this variability are important because it affects divers phenomena such as runoff, ground temperatures or slope movements. This study investigates the derivation of melting characteristics based on spatial clusters of temperature measurements. Results are based on data from Switzerland where ground surface temperatures were measured with miniature loggers (iButtons at 40 locations, referred to as footprints. At each footprint, ten iButtons have been distributed randomly few cm below the ground surface over an area of 10 m × 10 m. Footprints span elevations of 2100–3300 m a.s.l. and slope angles of 0–55°, as well as diverse slope expositions and types of surface cover and ground material. Based on two years of temperature data, the basal ripening date and the melt-out date are determined for each iButton, aggregated to the footprint level and further analysed. The date of melt out could be derived for nearly all iButtons, the ripening date could be extracted for only approximately half of them because it requires ground freezing below the snow pack. The variability within a footprint is often considerable and one to three weeks difference between melting or ripening of the points in one footprint is not uncommon. The correlation of mean annual ground surface temperatures, ripening date and melt-out date is moderate, making them useful intuitive complementary measured for model evaluation.

  10. Supplementary report on surface-water and ground-water surveys, Nueces River Basin, Texas

    Science.gov (United States)

    Broadhurst, W.L.; Ellsworth, C.E.

    1950-01-01

    A report on the ground-water and surface-water surveys of the Nueces River Basin was included in a report by the Bureau of Reclamation, entitled "Comprehensive plan for water-resources development of the Nueces River Basin project planning report number 5-14.04-3, February 1946".

  11. Ground states for a modified capillary surface equation in weighted Orlicz-Sobolev space

    Directory of Open Access Journals (Sweden)

    Guoqing Zhang

    2015-03-01

    Full Text Available In this article, we prove a compact embedding theorem for the weighted Orlicz-Sobolev space of radially symmetric functions. Using the embedding theorem and critical points theory, we prove the existence of multiple radial solutions and radial ground states for the following modified capillary surface equation $$\\displaylines{ -\\operatorname{div}\\Big(\\frac{|\

  12. Evaluation of the ground surface Enthalpy balance from bedrock shallow borehole temperatures (Livingston Island, Maritime Antarctic

    Directory of Open Access Journals (Sweden)

    M. Ramos

    2008-03-01

    Full Text Available The annual evolution of the ground temperatures from Incinerador borehole in Livingston Island (South Shetlands, Antarctic is studied. The borehole is 2.4 m deep and is located in a quartzite outcrop in the proximity of the Spanish Antarctic Station Juan Carlos I. In order to model the movement of the 0°C isotherm (velocity and maximum depth hourly temperature profiles from: (i the cooling periods of the frost seasons of 2000 to 2005, and (ii the warming periods of the thaw seasons of 2002–2003, 2003–2004 and 2004–2005, were studied. In this modelling approach, heat gains and losses across ground surface are considered to be the causes for the 0°C isotherm movement. A methodological approach to calculate the Enthalpy change based on the thermodynamic analysis of the ground during the cooling and warming periods is proposed. The Enthalpy change is equivalent to the heat exchange through the ground surface during each season, thus enabling to describe the interaction ground-atmosphere and providing valuable data for studies on permafrost and periglacial processes. The bedrock density is considered to be constant in the borehole and initial isothermal conditions at 0°C are assumed to run the model. The final stages correspond to the temperatures at the end of the cooling and warming periods (annual minima and maxima.

  13. A shear wave ground surface vibration technique for the detection of buried pipes

    Science.gov (United States)

    Muggleton, J. M.; Papandreou, B.

    2014-07-01

    A major UK initiative, entitled 'Mapping the Underworld' aims to develop and prove the efficacy of a multi-sensor device for accurate remote buried utility service detection, location and, where possible, identification. One of the technologies to be incorporated in the device is low-frequency vibro-acoustics; the application of this technology for detecting buried infrastructure, in particular pipes, is currently being investigated. Here, a shear wave ground vibration technique for detecting buried pipes is described. For this technique, shear waves are generated at the ground surface, and the resulting ground surface vibrations measured. Time-extended signals are employed to generate the illuminating wave. Generalized cross-correlation functions between the measured ground velocities and a reference measurement adjacent to the excitation are calculated and summed using a stacking method to generate a cross-sectional image of the ground. To mitigate the effects of other potential sources of vibration in the vicinity, the excitation signal can be used as an additional reference when calculating the cross-correlation functions. Measurements have been made at two live test sites to detect a range of buried pipes. Successful detection of the pipes was achieved, with the use of the additional reference signal proving beneficial in the noisier of the two environments.

  14. Evaluation of the ground surface Enthalpy balance from bedrock shallow borehole temperatures (Livingston Island, Maritime Antarctic)

    Science.gov (United States)

    Ramos, M.; Vieira, G.

    2008-03-01

    The annual evolution of the ground temperatures from Incinerador borehole in Livingston Island (South Shetlands, Antarctic) is studied. The borehole is 2.4 m deep and is located in a quartzite outcrop in the proximity of the Spanish Antarctic Station Juan Carlos I. In order to model the movement of the 0°C isotherm (velocity and maximum depth) hourly temperature profiles from: (i) the cooling periods of the frost seasons of 2000 to 2005, and (ii) the warming periods of the thaw seasons of 2002-2003, 2003-2004 and 2004-2005, were studied. In this modelling approach, heat gains and losses across ground surface are considered to be the causes for the 0°C isotherm movement. A methodological approach to calculate the Enthalpy change based on the thermodynamic analysis of the ground during the cooling and warming periods is proposed. The Enthalpy change is equivalent to the heat exchange through the ground surface during each season, thus enabling to describe the interaction ground-atmosphere and providing valuable data for studies on permafrost and periglacial processes. The bedrock density is considered to be constant in the borehole and initial isothermal conditions at 0°C are assumed to run the model. The final stages correspond to the temperatures at the end of the cooling and warming periods (annual minima and maxima).

  15. Seasonal Distribution of Trace Metals in Ground and Surface Water of Golaghat District, Assam, India

    Directory of Open Access Journals (Sweden)

    M. Boarh

    2010-01-01

    Full Text Available A study has been carried out on the quality of ground and surface water with respect to chromium, manganese, zinc, copper, nickel, cadmium and arsenic contamination from 28 different sources in the predominantly rural Golaghat district of Assam (India. The metals were analysed by using atomic absorption spectrometer. Water samples were collected from groundwater and surface water during the dry and wet seasons of 2008 from the different sources in 28 locations (samples. The results are discussed in the light of possible health hazards from the metals in relation to their maximum permissible limits. The study shows the quality of ground and surface water in a sizeable number of water samples in the district not to be fully satisfactory with respect to presence of the metals beyond permissible limits of WHO. The metal concentration of groundwater in the district follows the trend As>Zn>Mn>Cr>Cu>Ni>Cd in both the seasons.

  16. Ground-water, surface-water, and bottom-sediment contamination in the O-field area, Aberdeen Proving Ground, Maryland, and the possible effects of selected remedial actions on ground water

    Science.gov (United States)

    Vroblesky, Don A.; Lorah, Michelle M.; Oliveros, James P.

    1995-01-01

    Disposal of munitions and chemical-warfare substances has introduced inorganic and organic contaminants to the ground water, surface water, and bottom sediment at O-Field, in the Edgewood area of Aberdeen Proving Ground, Maryland. Contaminants include chloride, arsenic, transition metals, chlorinated aliphatic hydrocarbons, aromatic compounds, and organosulfur and organophosphorus compounds. The hydrologic effects of several remedial actions were estimated by use of a ground-water-flow model. The remedial actions examined were an impermeable covering, encapsulation, subsurface barriers, a ground-water drain, pumping of wells to manage water levels or to remove contaminated ground water for treatment, and no action.

  17. Determining the location of buried plastic water pipes from measurements of ground surface vibration

    Science.gov (United States)

    Muggleton, J. M.; Brennan, M. J.; Gao, Y.

    2011-09-01

    ‘Mapping the Underworld' is a UK-based project, which aims to create a multi-sensor device that combines complementary technologies for remote buried utility service detection and location. One of the technologies to be incorporated in the device is low-frequency vibro-acoustics, and techniques for detecting buried infrastructure, in particular plastic water pipes, are being investigated. One of the proposed techniques involves excitation of the pipe at some known location with concurrent vibrational mapping of the ground surface in order to infer the location of the remainder of the pipe. In this paper, measurements made on a dedicated pipe rig are reported. Frequency response measurements relating vibrational velocity on the ground to the input excitation were acquired. Contour plots of the unwrapped phase revealed the location of the pipe to within 0.1-0.2 m. Magnitude contour plots revealed the excitation point and also the location of the pipe end. By examining the unwrapped phase gradients along a line above the pipe, it was possible to identify the wave-type within the pipe responsible for the ground surface vibration. Furthermore, changes in the ground surface phase speed computed using this method enabled the location of the end of the pipe to be confirmed.

  18. Homogenization of seismic surface wave profiling in highly heterogeneous improved ground

    Science.gov (United States)

    Lin, C.; Chien, C.

    2012-12-01

    Seismic surface wave profiling is gaining popularity in engineering practice for determining shear-wave velocity profile since the two-station SASW (Spectral Analysis of Surface Wave) was introduced. Recent developments in the multi-station approach (Multi-station Analysis of Surface Wave, MASW) result in several convenient commercial tools. Unlike other geophysical tomography methods, the surface wave method is essentially a 1-D method assuming horizontally-layered medium. Nevertheless, MASW is increasingly used to map lateral variation of S-wave velocity by multiple surveys overlooking the effect of lateral heterogeneity. MASW typically requires long receiver spread in order to have enough depth coverage. The accuracy and lateral resolution of 2-D S-wave velocity imaging by surface wave is not clear. Many geotechnical applications involves lateral variation in a scale smaller than the geophone spread and wave length. For example, soft ground is often improved to increase strength and stiffness by methods such as jet grouting and stone column which result in heterogeneous ground with improved columns. Experimental methods (Standard Penetration Test, sampling and laboratory testing, etc.) used to assess such ground improvement are subjected to several limitations such as small sampling volume, time-consuming, and cost ineffectiveness. It's difficult to assess the average property of the improved ground and the actual replacement ratio of ground improvement. The use of seismic surface wave method for such a purpose seems to be a good alternative. But what MASW measures in such highly heterogeneous improved ground remains to be investigated. This study evaluated the feasibility of MASW in highly heterogeneous ground with improved columns and investigated the homogenization of shear wave velocity measured by MASW. Field experiments show that MASW testing in such a composite ground behaves similar to testing in horizontally layered medium. It seems to measure some sort

  19. INTERNAL STRUCTURE OF ASTEROIDS HAVING SURFACE SHEDDING DUE TO ROTATIONAL INSTABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Hirabayashi, Masatoshi [Research Associate, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States); Sánchez, Diego Paul [Senior Research Associate, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States); Scheeres, Daniel J., E-mail: masatoshi.hirabayashi@colorado.edu [Richard Seebass Chair, Professor, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States)

    2015-07-20

    Surface shedding of an asteroid is a failure mode where surface materials fly off due to strong centrifugal forces beyond the critical spin period, while the internal structure does not deform significantly. This paper proposes a possible structure of an asteroid interior that leads to surface shedding due to rapid rotation rates. A rubble pile asteroid is modeled as a spheroid composed of a surface shell and a concentric internal core, the entire assembly called the test body. The test body is assumed to be uniformly rotating around a constant rotation axis. We also assume that while the bulk density and the friction angle are constant, the cohesion of the surface shell is different from that of the internal core. First, developing an analytical model based on limit analysis, we provide the upper and lower bounds for the actual surface shedding condition. Second, we use a Soft-sphere Discrete Element Method (SSDEM) to study dynamical deformation of the test body due to a quasi-static spin-up. In this paper we show the consistency of both approaches. Additionally, the SSDEM simulations show that the initial failure always occurs locally and not globally. In addition, as the core becomes larger, the size of lofted components becomes smaller. These results imply that if there is a strong core in a progenitor body, surface shedding is the most likely failure mode.

  20. Investigating the Impacts of Surface Temperature Anomalies Due to Wildfires in Northern Sub-Saharan Africa

    Science.gov (United States)

    Gabbert, T.; Ichoku, C. M.; Matsui, T.; Capehart, W. J.

    2014-12-01

    The northern Sub-Saharan African region (NSSA) is an area of intense study due to the recent severe droughts that have dire consequences on the population, which relies mostly on rainfed agriculture for its food supply. This region's weather and hydrologic cycle are very complex and are dependent on the West African Monsoon. Different regional processes affect the West African Monsoon cycle and variability. One of the areas of current investigation is the water cycle response to the variability of land surface characteristics. Land surface characteristics are often altered in NSSA due to agricultural practices, grazing, and the fires that occur during the dry season. To better understand the effects of biomass burning on the hydrologic cycle of the sub-Saharan environment, an interdisciplinary team sponsored by NASA is analyzing potential feedback mechanisms due to the fires. As part of this research, this study focuses on the effects of land surface changes, particularly albedo and skin temperature, that are influenced by biomass burning. Surface temperature anomalies can influence the initiation of convective rainfall and surface albedo is linked to the absorption of solar radiation. To capture the effects of fire perturbations on the land surface, NASA's Unified Weather and Research Forecasting (NU-WRF) model coupled with NASA's Land Information System (LIS) is being used to simulate some of the fire-induced surface temperature anomalies and other environmental processes. In this presentation, we will report the strategy for these simulations, and show some preliminary results.

  1. Variation in surface fractal of graphite due to the adsorption of polyoxyethylene sorbitan monooleate

    Energy Technology Data Exchange (ETDEWEB)

    Hou Qingfeng [Research Center of Surface and Interface Chemical Engineering Technology, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Lu Xiancai [State Key Laboratory of Mineral Deposit Research, Department of Earth Sciences, Nanjing University, Nanjing 210093 (China); Liu Xiandong [State Key Laboratory of Mineral Deposit Research, Department of Earth Sciences, Nanjing University, Nanjing 210093 (China); Hu Baixing [Research Center of Surface and Interface Chemical Engineering Technology, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)]. E-mail: houqingfeng@nju.org.cn; Lu Zhijun [State Key Laboratory of Mineral Deposit Research, Department of Earth Sciences, Nanjing University, Nanjing 210093 (China); Shen Jian [Research Center of Surface and Interface Chemical Engineering Technology, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

    2005-02-15

    The fractal analysis is carried out to study the influence of adsorption of polyoxyethylene sorbitan monooleate (Tween 80) on the surface properties of graphite. The surface fractal dimension (dSF), BET surface area (SBET) and pore size distribution (PSD) are calculated from low temperature nitrogen adsorption isotherms. The decline in the dSF of graphite surface is found as the adsorption amount of Tween 80 increases, which suggests that the adsorbed Tween 80 smoothes the graphite surface. Additionally, the observation of atomic force microscopy (AFM) proves that the original slit pores in pure graphite are blocked up and the step defect sites are screened by Tween 80, which may result in the reduction of graphite roughness. The PSD pattern of graphite changes after the adsorption due to the pore blocking effect. SBET of the graphite decreases as the adsorption amount of Tween 80 increases, which is attributed to both pore blocking effect and surface screening effect.

  2. Surface and Internal Waves due to a Moving Load on a Very Large Floating Structure

    Directory of Open Access Journals (Sweden)

    Taro Kakinuma

    2012-01-01

    Full Text Available Interaction of surface/internal water waves with a floating platform is discussed with nonlinearity of fluid motion and flexibility of oscillating structure. The set of governing equations based on a variational principle is applied to a one- or two-layer fluid interacting with a horizontally very large and elastic thin plate floating on the water surface. Calculation results of surface displacements are compared with the existing experimental data, where a tsunami, in terms of a solitary wave, propagates across one-layer water with a floating thin plate. We also simulate surface and internal waves due to a point load, such as an airplane, moving on a very large floating structure in shallow water. The wave height of the surface or internal mode is amplified when the velocity of moving point load is equal to the surface- or internal-mode celerity, respectively.

  3. NUMERICAL ANALYSIS OF SATURATED-UNSATURATED SEEPAGE FLOW IN FRACTURED ROCK MASS DUE TO SURFACE INFILTRATION

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Seepage flow in fractured rock mass due to surface infiltration is a saturated-unsaturated seepage process. Aimed at rock mass with large fracture density, which can be equivalent to continuum, a mathematical model for saturated-unsaturated seepage flow in fractured rock mass due to surface infiltration was established in this paper. The Galerkin finite element method was used in numerical simulation and a finite element program used to calculate saturated-unsaturated seepage flow due to surface infiltration was worked out. A model experiment was employed examine the reasonableness of the program. The results show that the proposed model and program are reasonable. The application of the analysis method in this paper in an engineering project shows that the method is reliable and feasible.

  4. Numerical Modeling of Surface Deformation due to Magma Chamber Inflation/Deflation in a Heterogeneous Viscoelastic Half-space

    Science.gov (United States)

    Dichter, M.; Roy, M.

    2015-12-01

    Interpreting surface deformation patterns in terms of deeper processes in regions of active magmatism is challenging and inherently non-unique. This study focuses on interpreting the unusual sombrero-shaped pattern of surface deformation in the Altiplano Puna region of South America, which has previously been modeled as the effect of an upwelling diapir of material in the lower crust. Our goal is to investigate other possible interpretations of the surface deformation feature using a suite of viscoelastic models with varying material heterogeneity. We use the finite-element code PyLith to study surface deformation due to a buried time-varying (periodic) overpressure source, a magma body, at depth within a viscoelastic half-space. In our models, the magma-body is a penny-shaped crack, with a cylindrical region above the crack that is weak relative to the surrounding material. We initially consider a magma body within a homogeneous viscoelastic half-space to determine the effect of the free surface upon deformation above and beneath the source region. We observe a complex depth-dependent phase relationship between stress and strain for elements that fall between the ground surface and the roof of the magma body. Next, we consider a volume of weak material (faster relaxation time relative to background) that is distributed with varying geometry around the magma body. We investigate how surface deformation is governed by the spatial distribution of the weak material and its rheologic parameters. We are able to reproduce a "sombrero" pattern of surface velocities for a range of models with material heterogeneity. The wavelength of the sombrero pattern is primarily controlled by the extent of the heterogeneous region, modulated by flexural effects. Our results also suggest an "optimum overpressure forcing frequency" where the lifetime of the sombrero pattern (a transient phenomenon due to the periodic nature of the overpressure forcing) reaches a maximum. Through further

  5. Exploration of a Polarized Surface Bidirectional Reflectance Model Using the Ground-Based Multiangle SpectroPolarimetric Imager

    Directory of Open Access Journals (Sweden)

    David J. Diner

    2012-12-01

    Full Text Available Accurate characterization of surface reflection is essential for retrieval of aerosols using downward-looking remote sensors. In this paper, observations from the Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI are used to evaluate a surface polarized bidirectional reflectance distribution function (PBRDF model. GroundMSPI is an eight-band spectropolarimetric camera mounted on a rotating gimbal to acquire pushbroom imagery of outdoor landscapes. The camera uses a very accurate photoelastic-modulator-based polarimetric imaging technique to acquire Stokes vector measurements in three of the instrument’s bands (470, 660, and 865 nm. A description of the instrument is presented, and observations of selected targets within a scene acquired on 6 January 2010 are analyzed. Data collected during the course of the day as the Sun moved across the sky provided a range of illumination geometries that facilitated evaluation of the surface model, which is comprised of a volumetric reflection term represented by the modified Rahman-Pinty-Verstraete function plus a specular reflection term generated by a randomly oriented array of Fresnel-reflecting microfacets. While the model is fairly successful in predicting the polarized reflection from two grass targets in the scene, it does a poorer job for two manmade targets (a parking lot and a truck roof, possibly due to their greater degree of geometric organization. Several empirical adjustments to the model are explored and lead to improved fits to the data. For all targets, the data support the notion of spectral invariance in the angular shape of the unpolarized and polarized surface reflection. As noted by others, this behavior provides valuable constraints on the aerosol retrieval problem, and highlights the importance of multiangle observations.

  6. Internal Structure of Asteroids Having Surface Shedding due to Rotational Instability

    CERN Document Server

    Hirabayashi, Masatoshi; Scheeres, Daniel J

    2015-01-01

    Surface shedding of an asteroid is a failure mode where surface materials fly off due to strong centrifugal forces beyond the critical spin period, while the internal structure does not deform significantly. This paper proposes a possible structure of an asteroid interior that leads to such surface shedding due to rapid rotation rates. A rubble pile asteroid is modeled as a spheroid composed of a surface shell and a concentric internal core, the entire assembly called the test body. The test body is assumed to be uniformly rotating around a constant rotation axis. We also assume that while the bulk density and the friction angle are constant, the cohesion of the surface shell is different from that of the internal core. First, developing an analytical model based on limit analysis, we provide the upper and lower bounds for the actual surface shedding condition. Second, we use a Soft-Sphere Discrete Element Method (SSDEM) to study dynamical deformation of the test body due to a quasi-static spin-up. In this pa...

  7. Advantages of analytically computing the ground heat flux in land surface models

    Science.gov (United States)

    Pauwels, Valentijn R. N.; Daly, Edoardo

    2016-11-01

    It is generally accepted that the ground heat flux accounts for a significant fraction of the surface energy balance. In land surface models, the ground heat flux is typically estimated through a numerical solution of the heat conduction equation. Recent research has shown that this approach introduces errors in the estimation of the energy balance. In this paper, we calibrate a land surface model using a numerical solution of the heat conduction equation with four different vertical spatial resolutions. It is found that the thermal conductivity is the most sensitive parameter to the spatial resolution. More importantly, the thermal conductivity values are directly related to the spatial resolution, thus rendering any physical interpretation of this value irrelevant. The numerical solution is then replaced by an analytical solution. The results of the numerical and analytical solutions are identical when fine spatial and temporal resolutions are used. However, when using resolutions that are typical of land surface models, significant differences are found. When using the analytical solution, the ground heat flux is directly calculated without calculating the soil temperature profile. The calculation of the temperature at each node in the soil profile is thus no longer required, unless the model contains parameters that depend on the soil temperature, which in this study is not the case. The calibration is repeated, and thermal conductivity values independent of the vertical spatial resolution are obtained. The main conclusion of this study is that care must be taken when interpreting land surface model results that have been obtained using numerical ground heat flux estimates. The use of exact analytical solutions, when available, is recommended.

  8. Evaluation of the ground surface Enthalpy balance from bedrock temperatures (Livingston Island, Maritime Antarctic)

    Science.gov (United States)

    Ramos, M.; Vieira, G.

    2009-05-01

    The annual evolution of the ground temperatures from Incinerador borehole in Livingston Island (South Shetlands, Antarctic) is studied. The borehole is 2.4 m deep and is located in a massive quartzite outcrop with negligible water content, in the proximity of the Spanish Antarctic Station Juan Carlos I. In order to model the movement of the 0°C isotherm (velocity and maximum depth) hourly temperature profiles from: (i) the cooling periods of the frost season of 2000 to 2005, and (ii) the warming periods of the thaw season of 2002-2003, 2003-2004 and 2004-2005, were studied. In this modelling approach, heat gains and losses across the ground surface are assumed to be the causes for the 0°C isotherm movement. A methodological approach to calculate the ground Enthalpy change based on the thermodynamic analysis of the ground during the cooling and warming periods is proposed. The Enthalpy change into the rock is equivalent to the heat exchange through the ground surface during each season, thus enabling to describe the interaction ground-atmosphere and providing valuable data for studies on permafrost and periglacial processes. The bedrock density and thermal conductivity are considered to be constant and initial isothermal conditions at 0°C are assumed (based in collected data and local meteorological conditions in this area) to run the model in the beginning of each season. The final stages correspond to the temperatures at the end of the cooling and warming periods (annual minima and maxima). The application of this method avoids error propagation induced by the heat exchange calculations from multiple sensors using the Fourier method.

  9. Evaluation of the ground surface Enthalpy balance from bedrock temperatures (Livingston Island, Maritime Antarctic

    Directory of Open Access Journals (Sweden)

    M. Ramos

    2009-05-01

    Full Text Available The annual evolution of the ground temperatures from Incinerador borehole in Livingston Island (South Shetlands, Antarctic is studied. The borehole is 2.4 m deep and is located in a massive quartzite outcrop with negligible water content, in the proximity of the Spanish Antarctic Station Juan Carlos I. In order to model the movement of the 0°C isotherm (velocity and maximum depth hourly temperature profiles from: (i the cooling periods of the frost season of 2000 to 2005, and (ii the warming periods of the thaw season of 2002–2003, 2003–2004 and 2004–2005, were studied. In this modelling approach, heat gains and losses across the ground surface are assumed to be the causes for the 0°C isotherm movement. A methodological approach to calculate the ground Enthalpy change based on the thermodynamic analysis of the ground during the cooling and warming periods is proposed. The Enthalpy change into the rock is equivalent to the heat exchange through the ground surface during each season, thus enabling to describe the interaction ground-atmosphere and providing valuable data for studies on permafrost and periglacial processes. The bedrock density and thermal conductivity are considered to be constant and initial isothermal conditions at 0°C are assumed (based in collected data and local meteorological conditions in this area to run the model in the beginning of each season. The final stages correspond to the temperatures at the end of the cooling and warming periods (annual minima and maxima. The application of this method avoids error propagation induced by the heat exchange calculations from multiple sensors using the Fourier method.

  10. Collapse ratios of buildings due to the 1995 Kobe earthquake and interference between S-wave and the second surface wave at basin edge

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhixin; XU Jiren; Ryuji Kubota; Wakizawa Yasuhiko; Kajikawa Syozo

    2004-01-01

    The distribution characteristics of collapse ratios of buildings in Kobe city due to the 1995 M7.2 Hyogo-ken Nanbu, Japan (Kobe) earthquake and the interferences due to SH or P-SV and the second surface waves propagating in heterogeneous medium are discussed in this paper by using numerical simulation technique of wave equation. The staggered grid real value fast Fourier transform differentiation (SGRFFTD) is used in the pseudospectral method of ground motion simulations because of its speed, high stability and accuracy. The results show that the maximum amplitude of simulated acceleration waveforms on the ground coincides well with the complicated distributions of collapse ratios of buildings. The peak collapse ratio of buildings away from the earthquake fault also coincides well with the peak ground acceleration. The spatial interference process is analyzed by using the snap shots of seismic wave propagation. The peak ground acceleration is probably caused by the interferences due to the second surface wave transmitting from the bedrock to sedimentary basin and the upward body wave. Analyses of the interference process show that seismic velocity structure and geologic structure strongly influence the distribution of the maximum amplitude of acceleration waveforms. Interferences occurring near the basin boundary are probably the cause of the peak collapse ratio of buildings away from the fault. Therefore it is necessary to analyze wave propagations and interference process using numerical simulation strategy for studies on the seismic disasters.

  11. Ground surface temperature and humidity, ground temperature cycles and the ice table depths in University Valley, McMurdo Dry Valleys of Antarctica

    Science.gov (United States)

    Fisher, David A.; Lacelle, Denis; Pollard, Wayne; Davila, Alfonso; McKay, Christopher P.

    2016-11-01

    In the upper McMurdo Dry Valleys, 90% of the measured ice table depths range from 0 to 80 cm; however, numerical models predict that the ice table is not in equilibrium with current climate conditions and should be deeper than measured. This study explored the effects of boundary conditions (air versus ground surface temperature and humidity), ground temperature cycles, and their diminishing amplitude with depth and advective flows (Darcy flow and wind pumping) on water vapor fluxes in soils and ice table depths using the REGO vapor diffusion model. We conducted a series of numerical experiments that illustrated different hypothetical scenarios and estimated the water vapor flux and ice table depth using the conditions in University Valley, a small high elevation valley. In situ measurements showed that while the mean annual ground surface temperature approximates that in the air, the mean annual ground surface relative humidity (>85%ice) was significantly higher than in the atmosphere ( 50%ice). When ground surface temperature and humidity were used as boundary conditions, along with damping diurnal and annual temperature cycles within the sandy soil, REGO predicted that measured ice table depths in the valley were in equilibrium with contemporary conditions. Based on model results, a dry soil column can become saturated with ice within centuries. Overall, the results from the new soil data and modeling have implications regarding the factors and boundary conditions that affect the stability of ground ice in cold and hyperarid regions where liquid water is rare.

  12. Electric Signals on and under the Ground Surface Induced by Seismic Waves

    Directory of Open Access Journals (Sweden)

    Akihiro Takeuchi

    2012-01-01

    Full Text Available We constructed three observation sites in northeastern Japan (Honjo, Kyowa, and Sennan with condenser-type large plate electrodes (4 × 4 m2 as sensors supported 4 m above the ground and with pairs of reference electrodes buried vertically at 0.5 m and 2.5 m depth (with a ground velocity sensor at Sennan only. Electrical signals of an earthquake (M6.3 in northeastern Japan were detected simultaneously with seismic waves. Their waveforms were damped oscillations, with greatly differing signal amplitudes among sites. Good positive correlation was found between the amplitudes of signals detected by all electrodes. We propose a signal generation model: seismic acceleration vertically shook pore water in the topsoil, generating the vertical streaming potential between the upper unsaturated water zone and the lower saturated water zone. Maximum electric earth potential difference was observed when one electrode was in the saturated water zone, and the other was within the unsaturated water zone, but not when the electrodes were in the saturated water zone. The streaming potential formed a charge on the ground surface, generating a vertical atmospheric electric field. The large plate electrode detected electric signals related to electric potential differences between the electrode and the ground surface.

  13. Assessment, management rehabilitation of surface water losses due to longwall coal mining subsidence

    Energy Technology Data Exchange (ETDEWEB)

    Dawkins, A.P. [Coffey Geosciences Pty. Ltd., Sydney, NSW (Australia)

    1999-07-01

    Subsidence due to longwall coal mining has generated notable effects on surface water and groundwater above numerous longwall coal mines in Queensland and NSW. This paper deals with the methods which can be used to assess, predict and rehabilitate the effects of longwall surface subsidence on surface water bodies. Aspects discussed cover the subsidence model, hydrological and hydrogeological assessment, hydrogeochemical changes and subsidence rehabilitation issues. The paper concludes that longwall surface subsidence can significantly affect the mine's local environment. However, with sufficient baseline data and a thorough assessment of site specific issues, longwalls can be planned to account for subsidence effects on surface water, and possible deleterious effects can be mitigated. 20 refs., 4 figs.

  14. Kinetics of the forelimb in horses circling on different ground surfaces at the trot.

    Science.gov (United States)

    Chateau, Henry; Camus, Mathieu; Holden-Douilly, Laurène; Falala, Sylvain; Ravary, Bérangère; Vergari, Claudio; Lepley, Justine; Denoix, Jean-Marie; Pourcelot, Philippe; Crevier-Denoix, Nathalie

    2013-12-01

    Circling increases the expression of distal forelimb lameness in the horse, depending on rein, diameter and surface properties of the circle. However, there is limited information about the kinetics of horses trotting on circles. The aim of this study was to quantify ground reaction force (GRF) and moments in the inside and outside forelimb of horses trotting on circles and to compare the results obtained on different ground surfaces. The right front hoof of six horses was equipped with a dynamometric horseshoe, allowing the measurement of 3-dimensional GRF, moments and trajectory of the centre of pressure. The horses were lunged at slow trot (3 m/s) on right and left 4 m radius circles on asphalt and on a fibre sand surface. During circling, the inside forelimb produced a smaller peak vertical force and the stance phase was longer in comparison with the outside forelimb. Both right and left circling produced a substantial transversal force directed outwards. On a soft surface (sand fibre), the peak transversal force and moments around the longitudinal and vertical axes of the hoof were significantly decreased in comparison with a hard surface (asphalt). Sinking of the lateral or medial part of the hoof in a more compliant surface enables reallocation of part of the transversal force into a proximo-distal force, aligned with the limb axis, thus limiting extrasagittal stress on the joints.

  15. Correlation between Increases of the Annual Global Solar Radiation and the Ground Albedo Solar Radiation due to Desertification—A Possible Factor Contributing to Climatic Change

    Directory of Open Access Journals (Sweden)

    Emanuele Calabrò

    2016-12-01

    Full Text Available Background: This study investigates the connection between annual global solar radiation and ground albedo solar radiation due to desertification in line with previous research on the correlation between climatic changes and desertification. Methods: A simulation study was performed using an algorithm formulated by the authors and the typical albedo coefficient values of forested ground, green grass and desert sand. Results: It is shown that changing the albedo coefficients from values corresponding to forested ground or green grass to values corresponding to the desert sand causes a significant increase in the annual global solar radiation acquired at different latitudes, leading one to hypothesize a mechanism of reduction of convective overturning and precipitation decreases due to desertification. Conclusion: In this scenario, modifications of local and global climate can be connected to changes of ground solar albedo induced by desertification.

  16. Real-time Accurate Surface Reconstruction Pipeline for Vision Guided Planetary Exploration Using Unmanned Ground and Aerial Vehicles

    Science.gov (United States)

    Almeida, Eduardo DeBrito

    2012-01-01

    This report discusses work completed over the summer at the Jet Propulsion Laboratory (JPL), California Institute of Technology. A system is presented to guide ground or aerial unmanned robots using computer vision. The system performs accurate camera calibration, camera pose refinement and surface extraction from images collected by a camera mounted on the vehicle. The application motivating the research is planetary exploration and the vehicles are typically rovers or unmanned aerial vehicles. The information extracted from imagery is used primarily for navigation, as robot location is the same as the camera location and the surfaces represent the terrain that rovers traverse. The processed information must be very accurate and acquired very fast in order to be useful in practice. The main challenge being addressed by this project is to achieve high estimation accuracy and high computation speed simultaneously, a difficult task due to many technical reasons.

  17. Geophysical Monitoring of Ground Surface Deformation Associated with a Confined Aquifer Storage and Recovery Operation

    Science.gov (United States)

    Bonneville, Alain; Heggy, Essam; Strickland, Christopher; Normand, Jonathan; Dermond, Jeffrey; Fang, Yilin; Sullivan, Charlotte

    2015-08-01

    One important issue in the storage of large volumes of fluids, mainly water and CO2, in the deep subsurface is to determine the resulting field-scale-induced displacements and consequences of overpressures on the mechanical integrity of the storage reservoir and surroundings. A quantifiable estimation of displacement can be made by combining the robust, cost-effective, and repeatable geophysical techniques of micro-gravimetry, differential global positioning system (DGPS), and differential synthetic aperture radar interferometry (DInSAR). These techniques were field tested and evaluated for the first time on an active large-volume aquifer storage and recovery (ASR) project in Pendleton, Oregon, USA, where three ASR wells are injecting up to 1.9 million m3 year-1 into basalt aquifers to a depth of about 150 m. Injection and recovery of water at the wells are accompanied by significant gravity anomalies and vertical deformation of the ground surface localized to the immediate surroundings of the injection wells as evidenced by DGPS and gravity measurements collected in 2011. At a larger scale, and between 2011 and 2013, DInSAR monitoring of the Pendleton area shows sub- centimetric deformation in the western part of the city and close to the injection locations associated with ASR cycle. Deformations are found to be temporally out phased with the injection and recovery events due to complex groundwater flow. A numerical simulation of the effect of the water injection gives results in good agreement with the observations and confirms the validity of the approach, which could be deployed in similar geological contexts to look at the mechanical effects of water and gas injections.

  18. Limitations of Heat Conductivity in Cryogenic Sensors Due to Surface Roughness

    NARCIS (Netherlands)

    Moktadir, Z.; Bruijn, M.P.; Wiegerink, Remco J.; Elwenspoek, Michael Curt; Ridder, M.; Mels, W.A.

    2002-01-01

    The limitation of heat conductivity in cryogenic sensors due to surface roughness was discussed. It was found that at macroscopic scale and high temperatures, the transport coefficients were characteristic properties of the material and were independent of the shape and size of specimen. An

  19. New Measurements from Old Boreholes: A Look at Interaction Between Surface Air Temperature and Ground Surface Temperature

    Science.gov (United States)

    Heinle, S. M.; Gosnold, W. D.

    2007-12-01

    We recently logged new field measurements of several boreholes throughout the Midwest, including North Dakota, South Dakota, and Nebraska. We then compared these new measurements against measurements previously obtained. Our comparisons included inverse modeling of past and recent measurements as well as climate modeling based on past surface air temperatures obtained from the weather stations. The data show a good correlation between climate warming in the last century and ground surface warming. Of particular importance is that cooling of air temperatures beginning in the mid 1990s reflects in the ground surface temperatures. The boreholes included in the study consist of three boreholes located in north central North Dakota, including two deeper than 200 meters. Two boreholes in the southwestern part of South Dakota, and two from southeastern South Dakota, all approximately 180 meters deep. Also included, were two boreholes (135 meters and over 200 meters deep) located in southwestern Nebraska, and two boreholes in the panhandle of Nebraska, each over 100 meters deep. We obtained historical surface air temperature from climate stations located near the boreholes, both from the United States Historical Climatology Network and from the Western Regional Climate Center.

  20. ON GROUND SURFACE EXTRACTION USING FULL-WAVEFORM AIRBORNE LASER SCANNER FOR CIM

    OpenAIRE

    Nakano, K.; H. Chikatsu

    2015-01-01

    Satellite positioning systems such as GPS and GLONASS have created significant changes not only in terms of spatial information but also in the construction industry. It is possible to execute a suitable construction plan by using a computerized intelligent construction. Therefore, an accurate estimate of the amount of earthwork is important for operating heavy equipment, and measurement of ground surface with high accuracy is required. A full-waveform airborne laser scanner is expected to be...

  1. Efficiency of silver nanoparticles against bacterial contaminants isolated from surface and ground water in Egypt

    Directory of Open Access Journals (Sweden)

    Reem Dosoky

    2015-06-01

    Full Text Available The bactericidal efficiency of silver nanoparticles (AgNP was evaluated against bacteria isolated from surface and ground water samples in Egypt. The AgNP were synthesized by typical one-step synthesis protocol, and were characterized using transmission electron microscopy and atomic absorption spectrophotometer. The bactericidal efficiency of AgNP was evaluated by its application in three concentrations i.e., 0.1, 0.05 and 0.01 ppm to water sample, and allowed to interact with bacteria for different duration e.g., 5 min 15 min, 30 min, 1 h and 2 h. Then, the bactericidal efficiency of AgNPs was determined by comparing the counted bacteria before and after the treatments. Higher mean values of total bacterial count (TBC, total coliform count (TCC, and total streptococcal count (TFS were detected in surface water than in ground water. Also, the results showed that TBC, TCC and TFS exceeded permissible limits. Application of AgNP at different concentration, the number of bacteria in TBC was significantly reduced in all AgNP-exposed samples as compared to the control group (p<0.05. The highest concentration of AgNP exhibited highest bactericidal efficiency in TBC, where, after two hours, 0.1, 0.05 and 0.01 mg/L AgNP was found to be sufficient to inhibit 91.85, 89.14 and 74.92%, and 92.33, 85.23 and 53.17% in TBC of surface and ground water, respectively. Moreover, the inhibition efficiency of the highest concentration (0.1 ppm against TCC reached to 98.10 and 99.88% in surface water and 95.54 and 99.20% in ground water after 1 h and 2 h, respectively. Similar results were found against TFS count. The AgNPs were found to be effective against bacteria of water origin.

  2. Derivation of Ground Surface and Vegetation in a Coastal Florida Wetland with Airborne Laser Technology

    Science.gov (United States)

    Raabe, Ellen A.; Harris, Melanie S.; Shrestha, Ramesh L.; Carter, William E.

    2008-01-01

    The geomorphology and vegetation of marsh-dominated coastal lowlands were mapped from airborne laser data points collected on the Gulf Coast of Florida near Cedar Key. Surface models were developed using low- and high-point filters to separate ground-surface and vegetation-canopy intercepts. In a non-automated process, the landscape was partitioned into functional landscape units to manage the modeling of key landscape features in discrete processing steps. The final digital ground surface-elevation model offers a faithful representation of topographic relief beneath canopies of tidal marsh and coastal forest. Bare-earth models approximate field-surveyed heights by + 0.17 m in the open marsh and + 0.22 m under thick marsh or forest canopy. The laser-derived digital surface models effectively delineate surface features of relatively inaccessible coastal habitats with a geographic coverage and vertical detail previously unavailable. Coastal topographic details include tidal-creek tributaries, levees, modest topographic undulations in the intertidal zone, karst features, silviculture, and relict sand dunes under coastal-forest canopy. A combination of laser-derived ground-surface and canopy-height models and intensity values provided additional mapping capabilities to differentiate between tidal-marsh zones and forest types such as mesic flatwood, hydric hammock, and oak scrub. Additional derived products include fine-scale shoreline and topographic profiles. The derived products demonstrate the capability to identify areas of concern to resource managers and unique components of the coastal system from laser altimetry. Because the very nature of a wetland system presents difficulties for access and data collection, airborne coverage from remote sensors has become an accepted alternative for monitoring wetland regions. Data acquisition with airborne laser represents a viable option for mapping coastal topography and for evaluating habitats and coastal change on marsh

  3. Interpreting Ground Temperature Measurements for Thermophysical Properties on Complex Surfaces of the Moon and Mars

    Science.gov (United States)

    Vasavada, A. R.; Hamilton, V. E.; Team, M.

    2013-12-01

    With the successful deployments of the Diviner radiometer on the Lunar Reconnaissance Orbiter and the REMS ground temperature sensor on the Curiosity Mars rover, records of ground temperature with high accuracy and finely sampled diurnal and seasonal cycles have become available. The detailed shapes of these temperature profiles allow inferences beyond just bulk thermophysical properties. Subtle (or sometime significant) effects of surface roughness, slope, and lateral and vertical heterogeneity may be identified in the surface brightness temperature data. For example, changes in thermal or physical properties with depth in the shallow subsurface affect the conduction and storage of thermal energy. These affect the surface energy balance and therefore surface temperatures, especially the rate of cooling at night. Making unique determinations of subsurface soil properties requires minimizing the uncertainties introduced by other effects. On Mars, atmospheric aerosol opacity and wind-driven sensible heat fluxes also affect the diurnal and annual temperature profiles. On both bodies, variations in thermal inertia, slopes, roughness, albedo, and emissivity within the radiometer footprint will cause the composite brightness temperature to differ from a kinetic temperature. Nevertheless, we have detected potential effects of complex surfaces in the temperature data from both Diviner and Curiosity. On the Moon, the results reveal a nearly ubiquitous surface structure, created mechanically by impact gardening, that controls the thermal response of the surface. On Mars, the thermal response is controlled primarily by grain size, cementation, lithification, and composition. However, the secondary effects of near-surface layering aid in the interpretation of stratigraphy and in the identification of geologic processes that have altered the surface.

  4. Evaluation of arsenic and other physico-chemical parameters of surface and ground water of Jamshoro, Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Baig, Jameel Ahmed, E-mail: jab_mughal@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kazi, Tasneem Gul, E-mail: tgkazi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Arain, Muhammad Balal, E-mail: bilal_KU2004@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Afridi, Hassan Imran, E-mail: hassanimranafridi@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Kandhro, Ghulam Abbas, E-mail: gakandhro@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Sarfraz, Raja Adil, E-mail: rajaadilsarfraz@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Jamal, Muhammad Khan, E-mail: mkhanjamali@yahoo.com [Government Degree College Usta Muhammad, Balochistan 08300 (Pakistan); Shah, Abdul Qadir, E-mail: aqshah07@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan)

    2009-07-30

    Arsenic contamination in water has caused severe health problems around the world. The purpose of this study was to evaluate the geological and anthropogenic aspects of As pollution in surface and groundwater resources of Jamshoro Sindh, Pakistan. Hydride generator atomic absorption spectrophotometry (HG-AAS) is employed for the determination of arsenic in water samples, with detection limit of 0.02 {mu}g l{sup -1}. Arsenic concentrations in surface and underground water range from 3.0 to 50.0, and 13 to 106 {mu}g l{sup -1}, respectively. In most of the water samples As levels exceeded the WHO provisional guideline values 10 {mu}g l{sup -1}. The high level of As in under study area may be due to widespread water logging from Indus river irrigation system which causes high saturation of salts in this semi-arid region and lead to enrichment of As in shallow groundwater. Among the physico-chemical parameters, electrical conductivity, Na{sup +}, K{sup +}, and SO{sub 4}{sup 2-} were found to be higher in surface and ground water, while elevated levels of Ca{sup 2+} and Cl{sup -} were detected only in ground water than WHO permissible limit. The high level of iron was observed in ground water, which is a possible source of As enrichment in the study area. The multivariate technique (cluster analysis) was used for the elucidation of high, medium and low As contaminated areas. It may be concluded that As originate from coal combustion at brick factories and power generation plants, and it was mobilized promotionally by the alkaline nature of the understudy groundwater samples.

  5. Modeling ground surface uplift during CO2 sequestration: the case of In Salah, Algeria.

    Science.gov (United States)

    Rinaldi, Antonio Pio; Rutqvist, Jonny; Finsterle, Stefan; Liu, Hui-Hai

    2016-04-01

    Observable ground deformation, common in storage projects, carries useful information on processes occurring at the injection depth. The Krechba gas field at In Salah (Algeria) is one of the best known sites for studying ground surface deformation during geological storage. Being the first industrial-scale on-shore CO2 demonstration project, the site is well known for satellite-based ground-deformation monitoring data of remarkable quality. In this work, we carry out coupled fluid flow and geomechanical simulations to understand the uplift at three different CO2 injection wells (KB-501, KB-502, KB-503). Previous numerical studies focused on the KB-502 injection well, where a double-lobe uplift pattern has been observed in the ground-deformation data. The observed uplift patterns at KB-501 and KB-503 are different, but also indicate the influence of deep fracture zone mechanical responses. The current study improves the previous modeling approach by introducing an injection reservoir and a fracture zone, both responding to a Mohr-Coulomb failure criterion. In addition, we model a stress-dependent permeability and bulk modulus, according to a dual continuum model. Mechanical and hydraulic properties were determined through inverse modeling by matching the simulated spatial and temporal evolution of uplift to the corresponding InSAR observations as well as by matching simulated and measured pressures. The numerical simulations are in excellent agreement with observed spatial and temporal variation of ground surface uplift, as well as with measured pressures. The estimated values for the parameterized mechanical and hydraulic properties are in good agreement with previous numerical results, although with uncertainty.

  6. Image current heating on a metal surface due to charged bunches

    Directory of Open Access Journals (Sweden)

    Xintian E. Lin

    2000-10-01

    Full Text Available When charged particles pass through a metal pipe, they are accompanied by an image current on the metal surface. With intense short bunches passing near or even into the metal surface, the peak image current density can be very high. This current may result in substantial temperature rise on the surface, especially in high peak current, multibunch operation. In this paper, we derive an explicit formula for the surface temperature rise due to this previously unrecognized pulsed heating effect and show that this effect dominates the proposed linear coherent light source collimator spoiler and wire scanner heating. Without proper account, it can result in component and instrument failures. The result also applies to optical transition radiation screens, profile screens, wire scanners, exit windows, and targets, which the beam crosses.

  7. Accumulation of microswimmers near surface due to steric confinement and rotational Brownian motion

    Science.gov (United States)

    Li, Guanglai; Tang, Jay

    2009-03-01

    Microscopic swimmers display some intriguing features dictated by Brownian motion, low Reynolds number fluid mechanics, and boundary confinement. We re-examine the reported accumulation of swimming bacteria or bull spermatozoa near the boundaries of a fluid chamber, and propose a kinematic model to explain how collision with surface, confinement and rotational Brownian motion give rise to the accumulation of micro-swimmers near a surface. In this model, an elongated microswimmer invariably travels parallel to the surface after hitting it from any incident angle. It then takes off and swims away from the surface after some time due to rotational Brownian motion. Based on this analysis, we obtain through computer simulation steady state density distributions that reproduce the ones measured for the small bacteria E coli and Caulobacter crescentus, as well as for the much larger bull spermatozoa swimming near surfaces. These results suggest strongly that Brownian dynamics and surface confinement are the dominant factors for the accumulation of microswimmers near a surface.

  8. Surface damage of metallic implants due to mechanical loading and chemical reactions

    Science.gov (United States)

    Ryu, Jaejoong

    The present study investigates interfacial damage mechanism of modular implants due to synergetic action of mechanical contact loading and corrosion. Modular implants are manufactured such that surfaces have a characteristic degree of roughness determined by tool tip size and motion of tool path or feeding speed. The central hypothesis for this work is that during contact loading of metallic implants, mechanisms of damage and dissolution are determined by contact loads, plastic deformation, residual stresses and environmental conditions at the nanoscale surface asperities; while during subsequent rest periods, mechanism of metallic dissolution is determined by the environmental conditions and residual stress field induced due to long range elastic interactions of the plastically deformed asperities. First part of the thesis is focused on investigating the mechanisms underlying surface roughness evolution due to stress-assisted dissolution during the rest period. The latter part is focused on investigating material removal mechanisms during single asperity contact of implant surfaces. Experimental study was performed to elucidate the roughness evolution mechanism by combined effect of multi-asperity contact and environmental corrosion. Cobalt-chromium-molybdenum specimen was subjected to either contact loading alone or alternating contact loading and exposure to reactive environment. Roughness of the specimen surface was monitored by optical profilometry and Fast Fourier Transform (FFT) calculation was used to characterize the evolving behavior of roughness modes. Finite element analysis (FEA) was employed to identify influences of surface morphological configurations and contact pressures on the residual stress development. Analytical model of multi-asperity contact has been developed for prediction of residual stress field for different roughness configurations during varying magnitude of contact loads based on elastic inclusion theory. Experimental results

  9. Surface Gap Soliton Ground States for the Nonlinear Schr\\"{o}dinger Equation

    CERN Document Server

    Dohnal, Tomáš; Reichel, Wolfgang

    2010-01-01

    We consider the nonlinear Schr\\"{o}dinger equation $(-\\Delta +V(x))u = \\Gamma(x) |u|^{p-1}u$, $x\\in \\R^n$ with $V(x) = V_1(x) \\chi_{\\{x_1>0\\}}(x)+V_2(x) \\chi_{\\{x_10\\}}(x)+\\Gamma_2(x) \\chi_{\\{x_1<0\\}}(x)$ and with $V_1, V_2, \\Gamma_1, \\Gamma_2$ periodic in each coordinate direction. This problem describes the interface of two periodic media, e.g. photonic crystals. We study the existence of ground state $H^1$ solutions (surface gap soliton ground states) for $0<\\min \\sigma(-\\Delta +V)$. Using a concentration compactness argument, we provide an abstract criterion for the existence based on ground state energies of each periodic problem (with $V\\equiv V_1, \\Gamma\\equiv \\Gamma_1$ and $V\\equiv V_2, \\Gamma\\equiv \\Gamma_2$) as well as a more practical criterion based on ground states themselves. Examples of interfaces satisfying these criteria are provided. In 1D it is shown that, surprisingly, the criteria can be reduced to conditions on the linear Bloch waves of the operators $-\\tfrac{d^2}{dx^2} +V_1(x)$ an...

  10. Relationship between subsurface damage and surface roughness of ground optical materials

    Institute of Scientific and Technical Information of China (English)

    LI Sheng-yi; WANG Zhuo; WU Yu-lie

    2007-01-01

    A theoretical model of relationship between subsurface damage and surface roughness was established to realize rapid and non-destructive measurement of subsurface damage of ground optical materials. Postulated condition of the model was that subsurface damage depth and peak-to-valley surface roughness are equal to depth of radial and lateral cracks in brittle surface induced by small-radius (radius≤200 μm) spherical indenter, respectively. And contribution of elastic stress field to the radial cracks propagation was also considered in the loading cycle. Subsurface damage depth of ground BK7 glasses was measured by magnetorheological finishing spot technique to validate theoretical ratio of subsurface damage to surface roughness. The results show that the ratio is directly proportional to load of abrasive grains and hardness of optical materials, while inversely proportional to granularity of abrasive grains and fracture toughness of optical materials. Moreover, the influence of the load and fracture toughness on the ratio is more significant than the granularity and hardness, respectively. The measured ratios of 80 grit and 120 grit fixed abrasive grinding of BK7 glasses are 5.8 and 5.4, respectively.

  11. Spectrally selective surfaces for ground and space-based instrumentation: support for a resource base

    Science.gov (United States)

    McCall, Susan H.; Sinclair, R. Lawrence; Pompea, Stephen M.; Breault, Robert P.

    1993-11-01

    The performance of space telescopes, space instruments, and space radiator systems depends critically upon the selection of appropriate spectrally selective surfaces. Many space programs have suffered severe performance limitations, schedule setbacks, and spent hundreds of thousands of dollars in damage control because of a lack of readily-accessible, accurate data on the properties of spectrally selective surfaces, particularly black surfaces. A Canadian effort is underway to develop a resource base (database and support service) to help alleviate this problem. The assistance of the community is required to make the resource base comprehensive and useful to the end users. The paper aims to describe the objectives of this project. In addition, a request for information and support is made for various aspects of the project. The resource base will be useful for both ground and space-based instrumentation.

  12. The Potential Energy Surface for the Electronic Ground State of H 2Se Derived from Experiment

    Science.gov (United States)

    Jensen, P.; Kozin, I. N.

    1993-07-01

    The present paper reports a determination of the potential energy surface for the electronic ground state of the hydrogen selenide molecule through a direct least-squares fitting to experimental data using the MORBID (Morse oscillator rigid bender internal dynamics) approach developed by P. Jensen [ J. Mol. Spectrosc.128, 478-501 (1988); J. Chem. Soc. Faraday Trans. 284, 1315-1340 (1988)]. We have fitted a selection of 303 rotation-vibration energy spacings of H 280Se, D 280Se, and HD 80Se involving J ≤ 5 with a root-mean-square deviation of 0.0975 cm -1 for the rotational energy spacings and 0.268 cm -1 for the vibrational spacings. In the fitting, 14 parameters were varied. On the basis of the fitted potential surface we have studied the cluster effect in the vibrational ground state of H 2Se, i.e., the formation of nearly degenerate, four-member groups of rotational energy levels [see I. N. Kozin, S. Klee, P. Jensen, O. L. Polyansky, and I. M. Pavlichenkov. J. Mol. Spectrosc., 158, 409-422 (1993), and references therein]. The cluster formation becomes more pronounced with increasing J. For example, four-fold clusters formed in the vibrational ground state of H 280Se at J = 40 are degenerate to within a few MHz. Our predictions of the D 280Se energy spectrum show that for this molecule, the cluster formation is displaced towards higher J values than arc found for H 280Se. In the vibrational ground state, the qualitative deviation from the usual rigid rotor picture starts at J = 12 for H 280Se and at J = 18 for D 280Se, in full agreement with predictions from semiclassical theory. An interpretation of the cluster eigenstates is discussed.

  13. Analysis of surface degradation of high density polyethylene (HDPE) insulation material due to tracking

    Indian Academy of Sciences (India)

    R Sarathi; S Chandrasekar; V Sabari Giri; C Venkataseshaiah; R Velmurugan

    2004-06-01

    In the present work, tracking phenomena has been studied with HDPE material under a.c. voltage, with ammonium chloride as the contaminant. It is noticed that the tracking time depends on the conductivity and flow rate of the contaminant. The diffusion coefficient of the material was obtained. The thermal and chemical stability of the material were identified by carrying out a methodical experimental study. The physico-chemical analyses viz. wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA), were carried out and it was concluded that the mechanism of tracking process is due to the surface degradation. The surface condition of the insulation structure was characterized for any surface discharges or tracking, using the leakage current measurement, utilizing the wavelet concepts.

  14. Influence of Holocene stratigraphic architecture on ground surface settlements: A case study from the City of Pisa (Tuscany, Italy)

    Science.gov (United States)

    Sarti, Giovanni; Rossi, Veronica; Amorosi, Alessandro

    2012-12-01

    The Holocene stratigraphic architecture of modern coastal and deltaic plains has peculiar characteristics that may influence ground surface settlements. In the Pisa urban area, the inhomogeneous spatial distribution of geotechnically weak layers, typically formed during the mid-late Holocene (highstand) coastal progradation, is inferred to be responsible for urban ground settlement and building damage, as evidenced by the tilt of several surface structures, among which the famous Leaning Tower of Pisa is the most prominent. On the basis of integrated stratigraphic, sedimentological and geotechnical data from a wide georeferenced database, three facies associations with high deformability potential (Units 1-3) are identified in the uppermost 30 m as opposed to depositional facies (Units 4-5) with higher geotechnical strength. Whereas Unit 1 represents a thick, laterally extensive lagoonal clay deposit, the overlying highly deformable units (Units 2-3) show more discontinuous spatial distribution controlled by the Holocene paleohydrographic evolution of the Arno coastal plain. Unit 2, dated between the Neolithic and the Etruscan age (ca. 5000-2000 yr BP), is composed of swamp clays and silty clays recording lagoon infilling due to Arno Delta progradation. Units 3 and 4, which consist of wet levee deposits and stiff floodplain clays, respectively, formed during the subsequent phases of alluvial plain construction started around the Roman age (from ca. 2000 yr BP). Whereas Units 3 and 4 are recorded within the uppermost 5 m, fluvial and distributary channel sands (Unit 5) cut the underlying deltaic-alluvial succession at various stratigraphic levels, down to Unit 1. The spatial distribution of these units gives rise to three, locally juxtaposed, stratigraphic motifs in Pisa underground, reflecting different potential risks for settlement under building loads. We show how lateral changes in stratigraphic architecture account for the irregular spatial distribution of

  15. Conceptual Tenets of the Theory of Hydration of Heterogeneous Surface with Polar Order of Disperse Ground Layers of Sedimentary Genesis

    Directory of Open Access Journals (Sweden)

    Tamara G. Makeeva

    2012-09-01

    Full Text Available The article, basing on the established regularity defines the basic tenets of the theory of hydration of heterogeneous surface with polar order of disperse ground layers of sedimentary genesis. It offers classification and formula for the associated water density, valid corrections for the associated water density, calculates the water film thickness in disperse ground, develops the reliable physicochemical model of the disperse ground, determines the range of applicability of the existing laboratory and field methods.

  16. On the resonance effects due to ground wires in transmission lines with non-uniform soil conductivity and non-uniform tower resistances

    Energy Technology Data Exchange (ETDEWEB)

    Faria, J.A. B. (Centro de Electrotecnia da Univ. Tecnica de Lisboa, Dept. of Electrical Engineering, Inst. Superior Tecnico, 1096 Lisboa Codex (PT))

    1992-01-01

    High frequency resonance effects due to shield wires grounding may affect carrier transmission performance at the vicinity of certain critical frequencies. In this paper the authors investigate if non-uniformities in soil conductivity and in tower footing resistances along the power line may lead to the suppression of such resonance effects. The simulation results the authors have obtained point towards a negative conclusion.

  17. Realization of Multi-Stable Ground States in a Nematic Liquid Crystal by Surface and Electric Field Modification

    Science.gov (United States)

    Gwag, Jin Seog; Kim, Young-Ki; Lee, Chang Hoon; Kim, Jae-Hoon

    2015-06-01

    Owing to the significant price drop of liquid crystal displays (LCDs) and the efforts to save natural resources, LCDs are even replacing paper to display static images such as price tags and advertising boards. Because of a growing market demand on such devices, the LCD that can be of numerous surface alignments of directors as its ground state, the so-called multi-stable LCD, comes into the limelight due to the great potential for low power consumption. However, the multi-stable LCD with industrial feasibility has not yet been successfully performed. In this paper, we propose a simple and novel configuration for the multi-stable LCD. We demonstrate experimentally and theoretically that a battery of stable surface alignments can be achieved by the field-induced surface dragging effect on an aligning layer with a weak surface anchoring. The simplicity and stability of the proposed system suggest that it is suitable for the multi-stable LCDs to display static images with low power consumption and thus opens applications in various fields.

  18. Mapping of permafrost surface using ground-penetrating radar at Kangerlussuaq Airport, western Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Anders Stuhr; Andreasen, Frank

    2007-01-01

    Kangerlussuaq Airport is located at 67°N and 51°W in the zone of continuous permafrost in western Greenland. Its proximity to the Greenlandic ice sheet results in a dry sub-arctic climate with a mean annual temperature of −5.7 °C. The airport is built on a river terrace mostly consisting of fluvial...... deposits overlying fine-grained marine melt-water sediments and bedrock. A ground-penetrating radar (GPR) survey was performed to study the frozen surface beneath the airfield. The measurements were carried out in late July 2005 on the southern parking area in Kangerlussuaq Airport. Five years earlier...

  19. Influence of geology on arsenic concentrations in ground and surface water in central Lesvos, Greece.

    Science.gov (United States)

    Aloupi, Maria; Angelidis, Michael O; Gavriil, Apostolos M; Koulousaris, Michael; Varnavas, Soterios P

    2009-04-01

    The occurrence of As was studied in groundwater used for human consumption and irrigation, in stream water and sediments and in water from thermal springs in the drainage basin of Kalloni Gulf, island of Lesvos, Greece, in order to investigate the potential influence of the geothermal field of Polichnitos-Lisvori on the ground and surface water systems of the area. Total dissolved As varied in the range geology exerts a determinant influence on As geochemical behaviour. On the other hand, the geothermal activity manifested in the area of Polichnitos-Lisvori does not affect the presence of As in groundwater and streams.

  20. Asymmetric Rock Pressure on Shallow Tunnel in Strata with Inclined Ground Surface

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiao-jun; YANG Chang-yu

    2007-01-01

    By building a tunnel model with a semi-circular crown, the asymmetric rock pressure applied to the shallow tunnel in strata with inclined ground surface is analyzed. Formulae, which not only include the parameters related to both tunnel structure and surrounding rock mass, but the overburden depth, are developed. The computation for four tunnel models show that the method presented is feasible and convenient. Furthermore, the influence of the overburden depth on the rock pressure is elaborated, and the criterion to identify the deep or shallow tunnels is formulated as well.

  1. Surface Signature Characterization at SPE through Ground-Proximal Methods: Methodology Change and Technical Justification

    Energy Technology Data Exchange (ETDEWEB)

    Schultz-Fellenz, Emily S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-09

    A portion of LANL’s FY15 SPE objectives includes initial ground-based or ground-proximal investigations at the SPE Phase 2 site. The area of interest is the U2ez location in Yucca Flat. This collection serves as a baseline for discrimination of surface features and acquisition of topographic signatures prior to any development or pre-shot activities associated with SPE Phase 2. Our team originally intended to perform our field investigations using previously vetted ground-based (GB) LIDAR methodologies. However, the extended proposed time frame of the GB LIDAR data collection, and associated data processing time and delivery date, were unacceptable. After technical consultation and careful literature research, LANL identified an alternative methodology to achieve our technical objectives and fully support critical model parameterization. Very-low-altitude unmanned aerial systems (UAS) photogrammetry appeared to satisfy our objectives in lieu of GB LIDAR. The SPE Phase 2 baseline collection was used as a test of this UAS photogrammetric methodology.

  2. Surface geophysical methods for characterising frozen ground in transitional permafrost landscapes

    Science.gov (United States)

    Briggs, Martin; Campbell, Seth; Nolan, Jay; Walvoord, Michelle Ann; Ntarlagiannis, Dimitrios; Day-Lewis, Frederick D.; Lane, John

    2017-01-01

    The distribution of shallow frozen ground is paramount to research in cold regions, and is subject to temporal and spatial changes influenced by climate, landscape disturbance and ecosystem succession. Remote sensing from airborne and satellite platforms is increasing our understanding of landscape-scale permafrost distribution, but typically lacks the resolution to characterise finer-scale processes and phenomena, which are better captured by integrated surface geophysical methods. Here, we demonstrate the use of electrical resistivity imaging (ERI), electromagnetic induction (EMI), ground penetrating radar (GPR) and infrared imaging over multiple summer field seasons around the highly dynamic Twelvemile Lake, Yukon Flats, central Alaska, USA. Twelvemile Lake has generally receded in the past 30 yr, allowing permafrost aggradation in the receded margins, resulting in a mosaic of transient frozen ground adjacent to thick, older permafrost outside the original lakebed. ERI and EMI best evaluated the thickness of shallow, thin permafrost aggradation, which was not clear from frost probing or GPR surveys. GPR most precisely estimated the depth of the active layer, which forward electrical resistivity modelling indicated to be a difficult target for electrical methods, but could be more tractable in time-lapse mode. Infrared imaging of freshly dug soil pit walls captured active-layer thermal gradients at unprecedented resolution, which may be useful in calibrating emerging numerical models. GPR and EMI were able to cover landscape scales (several kilometres) efficiently, and new analysis software showcased here yields calibrated EMI data that reveal the complicated distribution of shallow permafrost in a transitional landscape.

  3. Quality of surface and ground waters, Yakima Indian Reservation, Washington, 1973-74

    Science.gov (United States)

    Fretwell, M.O.

    1977-01-01

    This report describes the quality of the surface and ground waters of the Yakima Indian Reservation in south-central Washington, during the period November 1973-October 1974. The average dissolved-solids concentrations ranged from 48 to 116 mg/L (milligrams per liter) in the mountain streams, and from 88 to 372 mg/L in the lowland streams, drains, and a canal. All the mountain streams contain soft water (classified as 0-60 mg/L hardness as CaC03), and the lowland streams, drains, and canal contain soft to very hard water (more than 180 mg/L hardness as CaC03). The water is generally of suitable quality for irrigation, and neither salinity nor sodium hazards are a problem in waters from any of the streams studied. The specific conductance of water from the major aquifers ranged from 20 to 1 ,540 micromhos. Ground water was most dilute in mineral content in the Klickitat River basin and most concentrated in part of the Satus Creek basin. The ground water in the Satus Creek basin with the most concentrated mineral content also contained the highest percentage composition of sulfate, chloride, and nitrate. For drinking water, the nitrate-nitrogen concentrations exceeded the U.S. Public Health Service 's recommended limit of 10 mg/L over an area of several square miles, with a maximum observed concentration of 170 mg/L. (Woodard-USGS).

  4. Unsteady Free-surface Waves Due to a Submerged Body in Two-dimensional Oseen Flows

    Institute of Scientific and Technical Information of China (English)

    LUDong-qiang; AllenT.CHWANG

    2004-01-01

    The two-dimensional unsteady free-surface waves due to a submerged body moving in an incompressible viscous fluid of infinite depth is considered.The disturbed flow is governed by the unsteadyOseen equations with the kinematic and dynamic boundary conditions linearized for the free-surface waves.Accordingly, the body is mathematically simulated by an Oseenlet with a periodically oscillating strength.By means of Fourier transforms,the exact solution for the free-surface waves is expressed by an integral with a complex dispersion function, which explicitly shows that the wave dynamics is characterized by a Reynolds number and a Strouhal number.By applying Lighthill's theorem, asymptotic representations are derived for the far-field waves with a sub-critical and a super-critical Strouhal number. It is found that the generated waves due to the oscillating Oseenlet consist of the steady-state and transient responses. For the viscous flow with a sub-critical Strouhal number, there exist four waves: three propagate downstream while one propagates upstream.However, for the viscous flow with a super-critical Strouhal number, there exist two waves only,which propagate downstream.

  5. Mechanism and bounding of earthquake energy input to building structure on surface ground subjected to engineering bedrock motion

    OpenAIRE

    Kojima, K; Sakaguchi, K; Takewaki, I.

    2015-01-01

    The mechanism of earthquake energy input to building structures is clarified by considering the surface ground amplification and soil–structure interaction. The earthquake input energies to superstructures, soil–foundation systems and total swaying–rocking system are obtained by taking the corresponding appropriate free bodies into account and defining the energy transfer functions. It has been made clear that, when the ground surface motion is white, the input energy to the swaying–rocking m...

  6. Modeling surface and ground water mixing in the hyporheic zone using MODFLOW and MT3D

    Science.gov (United States)

    Lautz, Laura K.; Siegel, Donald I.

    2006-11-01

    We used a three-dimensional MODFLOW model, paired with MT3D, to simulate hyporheic zones around debris dams and meanders along a semi-arid stream. MT3D simulates both advective transport and sink/source mixing of solutes, in contrast to particle tracking (e.g. MODPATH), which only considers advection. We delineated the hydrochemically active hyporheic zone based on a new definition, specifically as near-stream subsurface zones receiving a minimum of 10% surface water within a 10-day travel time. Modeling results indicate that movement of surface water into the hyporheic zone is predominantly an advective process. We show that debris dams are a key driver of surface water into the subsurface along the experimental reach, causing the largest flux rates of water across the streambed and creating hyporheic zones with up to twice the cross-sectional area of other hyporheic zones. Hyporheic exchange was also found in highly sinuous segments of the experimental reach, but flux rates are lower and the cross-sectional areas of these zones are generally smaller. Our modeling approach simulated surface and ground water mixing in the hyporheic zone, and thus provides numerical approximations that are more comparable to field-based observations of surface-groundwater exchange than standard particle-tracking simulations.

  7. Modelling the Influence of Ground Surface Relief on Electric Sounding Curves Using the Integral Equations Method

    Directory of Open Access Journals (Sweden)

    Balgaisha Mukanova

    2017-01-01

    Full Text Available The problem of electrical sounding of a medium with ground surface relief is modelled using the integral equations method. This numerical method is based on the triangulation of the computational domain, which is adapted to the shape of the relief and the measuring line. The numerical algorithm is tested by comparing the results with the known solution for horizontally layered media with two layers. Calculations are also performed to verify the fulfilment of the “reciprocity principle” for the 4-electrode installations in our numerical model. Simulations are then performed for a two-layered medium with a surface relief. The quantitative influences of the relief, the resistivity ratios of the contacting media, and the depth of the second layer on the apparent resistivity curves are established.

  8. Increased dose near the skin due to electromagnetic surface beacon transponder.

    Science.gov (United States)

    Ahn, Kang-Hyun; Manger, Ryan; Halpern, Howard J; Aydogan, Bulent

    2015-05-08

    The purpose of this study was to evaluate the increased dose near the skin from an electromagnetic surface beacon transponder, which is used for localization and tracking organ motion. The bolus effect due to the copper coil surface beacon was evaluated with radiographic film measurements and Monte Carlo simulations. Various beam incidence angles were evaluated for both 6 MV and 18 MV experimentally. We performed simulations using a general-purpose Monte Carlo code MCNPX (Monte Carlo N-Particle) to supplement the experimental data. We modeled the surface beacon geometry using the actual mass of the glass vial and copper coil placed in its L-shaped polyethylene terephthalate tubing casing. Film dosimetry measured factors of 2.2 and 3.0 enhancement in the surface dose for normally incident 6 MV and 18 MV beams, respectively. Although surface dose further increased with incidence angle, the relative contribution from the bolus effect was reduced at the oblique incidence. The enhancement factors were 1.5 and 1.8 for 6 MV and 18 MV, respectively, at an incidence angle of 60°. Monte Carlo simulation confirmed the experimental results and indicated that the epidermal skin dose can reach approximately 50% of the dose at dmax at normal incidence. The overall effect could be acceptable considering the skin dose enhancement is confined to a small area (~ 1 cm2), and can be further reduced by using an opposite beam technique. Further clinical studies are justified in order to study the dosimetric benefit versus possible cosmetic effects of the surface beacon. One such clinical situation would be intact breast radiation therapy, especially large-breasted women.

  9. UNSTEADY WAVES DUE TO AN IMPULSIVE OSEENLET BENEATH THE CAPILLARY SURFACE OF A VISCOUS FLUID

    Institute of Scientific and Technical Information of China (English)

    LU Dong-qiang; CHEN Xiao-bo

    2008-01-01

    The two-dimensional free-surface waves due to a point force steadily moving beneath the capillary surface of an incompressible viscous fluid of infinite depth were analytically investigated. The unsteady Oseen equations were taken as the governing equations for the viscous flows. The kinematic and dynamic conditions including the combined effects of surface tension and viscosity were linearized for small-amplitude waves on the free-surface. The point force is modeled as an impulsive Oseenlet. The complex dispersion relation for the capillary-gravity waves shows that the wave patterns are characterized by the Weber number and the Reynolds number. The asymptotic expansions for the wave profiles were explicitly derived by means of Lighthill's theorem for the Fourier transform of a function with a finite number of singularities. Furthermore, it is found that the unsteady wave system consists of four families, that is, the steady-state gravity wave, the steady-state capillary wave, the transient gravity wave, and the transient capillary wave. The effect of viscosity on the capillary-gravity was analytically expressed.

  10. Spontaneous Emulsification of a Metal Drop Immersed in Slag Due to Dephosphorization: Surface Area Quantification

    Science.gov (United States)

    Assis, Andre N.; Warnett, Jason; Spooner, Stephen; Fruehan, Richard J.; Williams, Mark A.; Sridhar, Seetharaman

    2015-04-01

    When a chemical reaction occurs between two immiscible liquids, mass transfer is continuously taking place at the liquid-liquid interface. Several studies have shown that if the species being exchanged between the two liquids are surface-active, a very pronounced decrease in interfacial tension can occur which can lead to a phenomenon called spontaneous emulsification. In steelmaking, this behavior has been observed for several reactions that involve the transfer of impurities from molten steel to a molten-oxide slag but little quantification has been made. This work focuses on spontaneous emulsification due to the dephosphorization of a Fe-P drop immersed in a basic oxygen furnace type slag. An Au-image furnace attached to a confocal scanning laser microscope was used to rapidly heat and cool the samples at different times, and X-ray computerized tomography was used to perform the surface area calculations of the samples where the slag/steel reaction was allowed to occur for distinct times. The results show that the surface area of the metal drop rapidly increases by over one order of magnitude during the first 60 seconds of the reaction while the chemical reaction is occurring at a fast rate. Once the reaction slows down, approximately after 60 seconds, the droplets start to coalesce back together minimizing the surface area and returning to a geometry close to its equilibrium shape.

  11. Splitting of ISGMR strength in the light-mass nucleus $^{24}$Mg due to ground-state deformation

    CERN Document Server

    Gupta, Y K; Matta, J T; Patel, D; Peach, T; Hoffman, J; Yoshida, K; Itoh, M; Fujiwara, M; Hara, K; Hashimoto, H; Nakanishi, K; Yosoi, M; Sakaguchi, H; Terashima, S; Kishi, S; Murakami, T; Uchida, M; Yasuda, Y; Akimune, H; Kawabata, T; Harakeh, M N

    2015-01-01

    The isoscalar giant monopole resonance (ISGMR) strength distribution in $^{24}$Mg has been determined from background-free inelastic scattering of 386-MeV $\\alpha$ particles at extreme forward angles, including 0$^{\\circ}$. The ISGMR strength distribution has been observed for the first time to have a two-peak structure in a light-mass nucleus. This splitting of ISGMR strength is explained well by microscopic theory in terms of the prolate deformation of the ground state of $^{24}$Mg.

  12. Flux of benzo(a)pyrene to the ground surface and its distribution in the ecosystem

    Energy Technology Data Exchange (ETDEWEB)

    Milukaite, A. [Institute of Physics, Vilnius (Lithuania)

    1998-07-01

    Benzo(a)pyrene (BP) has been investigated in bulk atmospheric deposition, moss, needles of pine and some species of vascular plants. At two remote Lithuanian sites, for 1990-1995 the flux of benzo(a)pyrene from the atmosphere to the ground surface varied between 0.3 to 4.8 {mu}g{sup -2} mo{sup -1}. Consequently the territory of Lithuania (65,000 km{sup 2}) yearly was exposed to 624-2574 kg of carcinogen. The distribution of BP in soil and various vascular plant tissues (trifolium tepens, Elitrygea repens, Thymus serpyllum) indicates that benzo(a)pyrene is assimilated by flora. The concentration of BP is different in various organs of vascular plants and mostly depends on the degree of soil pollution. More than 300 samples of moss, mostly Hylocomium spendens and Pleurozium schreberi were analysed for BP. From 3.1 to 896.0 {mu}g kg{sup -1} of BP were measured in the moss samples. The flux of BP to the ground surface correlates well with its concentration in moss. A map of BP flux across Lithuania was created. 20 refs., 3 figs., 3 tabs.

  13. Human health impacts of drinking water (surface and ground) pollution Dakahlyia Governorate, Egypt

    Science.gov (United States)

    Mandour, R. A.

    2012-09-01

    This study was done on 30 drinking tap water samples (surface and ground) and 30 urine samples taken from patients who attended some of Dakahlyia governorate hospitals. These patients were complaining of poor-quality tap water in their houses, which was confirmed by this study that drinking water is contaminated with trace elements in some of the studied areas. The aim of this study was to determine the relationship between the contaminant drinking water (surface and ground) in Dakahlyia governorate and its impact on human health. This study reports the relationship between nickel and hair loss, obviously shown in water and urine samples. Renal failure cases were related to lead and cadmium contaminated drinking water, where compatibilities in results of water and urine samples were observed. Also, liver cirrhosis cases were related to iron-contaminated drinking water. Studies of these diseases suggest that abnormal incidence in specific areas is related to industrial wastes and agricultural activities that have released hazardous and toxic materials in the drinking water and thereby led to its contamination in these areas. We conclude that trace elements should be removed from drinking water for human safety.

  14. Analysis of selected herbicide metabolites in surface and ground water of the United States

    Science.gov (United States)

    Scribner, E.A.; Thurman, E.M.; Zimmerman, L.R.

    2000-01-01

    One of the primary goals of the US Geological Survey (USGS) Laboratory in Lawrence, Kansas, is to develop analytical methods for the analysis of herbicide metabolites in surface and ground water that are vital to the study of herbicide fate and degradation pathways in the environment. Methods to measure metabolite concentrations from three major classes of herbicides - triazine, chloroacetanilide and phenyl-urea - have been developed. Methods for triazine metabolite detection cover nine compounds: six compounds are detected by gas chromatography/mass spectrometry; one is detected by high-performance liquid chromatography with diode-array detection; and eight are detected by liquid chromatography/mass spectrometry. Two metabolites of the chloroacetanilide herbicides - ethane sulfonic acid and oxanilic acid - are detected by high-performance liquid chromatography with diode-array detection and liquid chromatography/mass spectrometry. Alachlor ethane sulfonic acid also has been detected by solid-phase extraction and enzyme-linked immunosorbent assay. Six phenylurea metabolites are all detected by liquid chromatography/mass spectrometry; four of the six metabolites also are detected by gas chromatography/mass spectrometry. Additionally, surveys of herbicides and their metabolites in surface water, ground water, lakes, reservoirs, and rainfall have been conducted through the USGS laboratory in Lawrence. These surveys have been useful in determining herbicide and metabolite occurrence and temporal distribution and have shown that metabolites may be useful in evaluation of non-point-source contamination. Copyright (C) 2000 Elsevier Science B.V.

  15. Ground-Water, Surface-Water, and Water-Chemistry Data, Black Mesa Area, Northeastern Arizona - 2006-07

    Science.gov (United States)

    Truini, Margot; Macy, J.P.

    2008-01-01

    The N aquifer is the major source of water in the 5,400 square-mile Black Mesa area in northeastern Arizona. Availability of water is an important issue in northeastern Arizona because of continued water requirements for industrial and municipal use and the needs of a growing population. Precipitation in the Black Mesa area is typically about 6 to 14 inches per year. The water-monitoring program in the Black Mesa area began in 1971 and is designed to provide information about the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. This report presents results of data collected for the monitoring program in the Black Mesa area from January 2006 to September 2007. The monitoring program includes measurements of (1) ground-water withdrawals, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, and (5) ground-water chemistry. Periodic testing of ground-water withdrawal meters is completed every 4 to 5 years. The Navajo Tribal Utility Authority (NTUA) yearly totals for the ground-water metered withdrawal data were unavailable in 2006 due to an up-grade within the NTUA computer network. Because NTUA data is often combined with Bureau of Indian Affairs data for the total withdrawals in a well system, withdrawals will not be published in this year's annual report. From 2006 to 2007, annually measured water levels in the Black Mesa area declined in 3 of 11 wells measured in the unconfined areas of the N aquifer, and the median change was 0.0 feet. Measurements indicated that water levels declined in 8 of 17 wells measured in the confined area of the aquifer. The median change for the confined area of the aquifer was 0.2 feet. From the prestress period (prior to 1965) to 2007, the median water-level change for 30 wells was -11.1 feet. Median water-level changes were 2.9 feet for 11 wells measured in the unconfined areas and -40.2 feet for 19 wells measured in the confined area. Spring flow was measured

  16. Seasonal Influences on Ground-Surface Water Interactions in an Arsenic-Affected Aquifer in Cambodia

    Science.gov (United States)

    Richards, L. A.; Magnone, D.; Van Dongen, B.; Bryant, C.; Boyce, A.; Ballentine, C. J.; Polya, D. A.

    2015-12-01

    Millions of people in South and Southeast Asia consume drinking water daily which contains dangerous levels of arsenic exceeding health-based recommendations [1]. A key control on arsenic mobilization in aquifers in these areas has been controversially identified as the interaction of 'labile' organic matter contained in surface waters with groundwaters and sediments at depth [2-4], which may trigger the release of arsenic from the solid- to aqueous-phase via reductive dissolution of iron-(hyr)oxide minerals [5]. In a field site in Kandal Province, Cambodia, which is an arsenic-affected area typical to others in the region, there are strong seasonal patterns in groundwater flow direction, which are closely related to monsoonal rains [6] and may contribute to arsenic release in this aquifer. The aim of this study is to explore the implications of the high susceptibility of this aquifer system to seasonal changes on potential ground-surface water interactions. The main objectives are to (i) identify key zones where there are likely ground-surface water interactions, (ii) assess the seasonal impact of such interactions and (iii) quantify the influence of interactions using geochemical parameters (such as As, Fe, NO3, NH4, 14C, 3T/3He, δ18O, δ2H). Identifying the zones, magnitude and seasonal influence of ground-surface water interactions elucidates new information regarding potential locations/pathways of arsenic mobilization and/or transport in affected aquifers and may be important for water management strategies in affected areas. This research is supported by NERC (NE/J023833/1) to DP, BvD and CJB and a NERC PhD studentship (NE/L501591/1) to DM. References: [1] World Health Organization, 2008. [2] Charlet & Polya (2006), Elements, 2, 91-96. [3] Harvey et al. (2002), Science, 298, 1602-1606. [4] Lawson et al. (2013), Env. Sci. Technol. 47, 7085 - 7094. [5] Islam et al. (2004), Nature, 430, 68-71. [6] Benner et al. (2008) Appl. Geochem. 23(11), 3072 - 3087.

  17. Variation in diffusion of gases through PDMS due to plasma surface treatment and storage conditions.

    Science.gov (United States)

    Markov, Dmitry A; Lillie, Elizabeth M; Garbett, Shawn P; McCawley, Lisa J

    2014-02-01

    Polydimethylsiloxane (PDMS) is a commonly used polymer in the fabrication of microfluidic devices due to such features as transparency, gas permeability, and ease of patterning with soft lithography. The surface characteristics of PDMS can also be easily changed with oxygen or low pressure air plasma converting it from a hydrophobic to a hydrophilic state. As part of such a transformation, surface methyl groups are removed and replaced with hydroxyl groups making the exposed surface to resemble silica, a gas impermeable substance. We have utilized Platinum(II)-tetrakis(pentaflourophenyl)porphyrin immobilized within a thin (~1.5 um thick) polystyrene matrix as an oxygen sensor, Stern-Volmer relationship, and Fick's Law of simple diffusion to measure the effects of PDMS composition, treatment, and storage on oxygen diffusion through PDMS. Results indicate that freshly oxidized PDMS showed a significantly smaller diffusion coefficient, indicating that the SiO2 layer formed on the PDMS surface created an impeding barrier. This barrier disappeared after a 3-day storage in air, but remained significant for up to 3 weeks if PDMS was maintained in contact with water. Additionally, higher density PDMS formulation (5:1 ratio) showed similar diffusion characteristics as normal (10:1 ratio) formulation, but showed 60 % smaller diffusion coefficient after plasma treatment that never recovered to pre-treatment levels even after a 3-week storage in air. Understanding how plasma surface treatments contribute to oxygen diffusion will be useful in exploiting the gas permeability of PDMS to establish defined normoxic and hypoxic oxygen conditions within microfluidic bioreactor systems.

  18. Surface-Water and Ground-Water Interactions in the Central Everglades, Florida

    Science.gov (United States)

    Harvey, Judson W.; Newlin, Jessica T.; Krest, James M.; Choi, Jungyill; Nemeth, Eric A.; Krupa, Steven L.

    2004-01-01

    Recharge and discharge are hydrological processes that cause Everglades surface water to be exchanged for subsurface water in the peat soil and the underlying sand and limestone aquifer. These interactions are thought to be important to water budgets, water quality, and ecology in the Everglades. Nonetheless, relatively few studies of surface water and ground water interactions have been conducted in the Everglades, especially in its vast interior areas. This report is a product of a cooperative investigation conducted by the USGS and the South Florida Water Management District (SFWMD) aimed at developing and testing techniques that would provide reliable estimates of recharge and discharge in interior areas of WCA-2A (Water Conservation Area 2A) and several other sites in the central Everglades. The new techniques quantified flow from surface water to the subsurface (recharge) and the opposite (discharge) using (1) Darcy-flux calculations based on measured vertical gradients in hydraulic head and hydraulic conductivity of peat; (2) modeling transport through peat and decay of the naturally occurring isotopes 224Ra and 223Ra (with half-lives of 4 and 11 days, respectively); and (3) modeling transport and decay of naturally occurring and 'bomb-pulse' tritium (half-life of 12.4 years) in ground water. Advantages and disadvantages of each method for quantifying recharge and discharge were compared. In addition, spatial and temporal variability of recharge and discharge were evaluated and controlling factors identified. A final goal was to develop appropriately simplified (that is, time averaged) expressions of the results that will be useful in addressing a broad range of hydrological and ecological problems in the Everglades. Results were compared with existing information about water budgets from the South Florida Water Management Model (SFWMM), a principal tool used by the South Florida Water Management District to plan many of the hydrological aspects of the

  19. Martian Surface Temperature and Spectral Response from the MSL REMS Ground Temperature Sensor

    Science.gov (United States)

    Martin-Torres, Javier; Martínez-Frías, Jesús; Zorzano, María-Paz; Serrano, María; Mendaza, Teresa; Hamilton, Vicky; Sebastián, Eduardo; Armiens, Carlos; Gómez-Elvira, Javier; REMS Team

    2013-04-01

    The Rover Environmental Monitoring Station (REMS) on the Mars Science Laboratory (MSL) offers the opportunity to explore the near surface atmospheric conditions and, in particular will shed new light into the heat budget of the Martian surface. This is important for studies of the atmospheric boundary layer (ABL), as the ground and air temperatures measured directly by REMS control the coupling of the atmosphere with the surface [Zurek et al., 1992]. This coupling is driven by solar insolation. The ABL plays an important role in the general circulation and the local atmospheric dynamics of Mars. One of the REMS sensors, the ground temperature sensor (GTS), provides the data needed to study the thermal inertia properties of the regolith and rocks beneath the MSL rover. The GTS includes thermopile detectors, with infrared bands of 8-14 µm and 16-20 µm [Gómez-Elvira et al., 2012]. These sensors are clustered in a single location on the MSL mast and the 8-14 µm thermopile sounds the surface temperature. The infrared radiation reaching the thermopile is proportional to the emissivity of the surface minerals across these thermal wavelengths. We have developed a radiative transfer retrieval method for the REMS GTS using a database of thermal infrared laboratory spectra of analogue minerals and their mixtures. [Martín Redondo et al. 2009, Martínez-Frías et al. 2012 - FRISER-IRMIX database]. This method will be used to assess the perfomance of the REMS GTS as well as determine, through the error analysis, the surface temperature and emissivity values where MSL is operating. Comparisons with orbiter data will be performed. References Gómez-Elvira et al. [2012], REMS: The Environmental Sensor Suite for the Mars Science Laboratory Rover, Space Science Reviews, Volume 170, Issue 1-4, pp. 583-640. Martín-Redondo et al. [2009] Journal of Environmental Monitoring 11:, pp. 1428-1432. Martínez-Frías et al. [2012] FRISER-IRMIX database http

  20. Splitting of ISGMR strength in the light-mass nucleus 24Mg due to ground-state deformation

    Directory of Open Access Journals (Sweden)

    Y.K. Gupta

    2015-09-01

    Full Text Available The isoscalar giant monopole resonance (ISGMR strength distribution in 24Mg has been determined from background-free inelastic scattering of 386-MeV α particles at extreme forward angles, including 0∘. The ISGMR strength distribution has been observed for the first time to have a two-peak structure in a light-mass nucleus. This splitting of ISGMR strength is explained well by microscopic theory in terms of the prolate deformation of the ground state of 24Mg.

  1. Robust Design Optimization Method for Centrifugal Impellers under Surface Roughness Uncertainties Due to Blade Fouling

    Institute of Scientific and Technical Information of China (English)

    JU Yaping; ZHANG Chuhua

    2016-01-01

    Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.

  2. Robust design optimization method for centrifugal impellers under surface roughness uncertainties due to blade fouling

    Science.gov (United States)

    Ju, Yaping; Zhang, Chuhua

    2016-03-01

    Blade fouling has been proved to be a great threat to compressor performance in operating stage. The current researches on fouling-induced performance degradations of centrifugal compressors are based mainly on simplified roughness models without taking into account the realistic factors such as spatial non-uniformity and randomness of the fouling-induced surface roughness. Moreover, little attention has been paid to the robust design optimization of centrifugal compressor impellers with considerations of blade fouling. In this paper, a multi-objective robust design optimization method is developed for centrifugal impellers under surface roughness uncertainties due to blade fouling. A three-dimensional surface roughness map is proposed to describe the nonuniformity and randomness of realistic fouling accumulations on blades. To lower computational cost in robust design optimization, the support vector regression (SVR) metamodel is combined with the Monte Carlo simulation (MCS) method to conduct the uncertainty analysis of fouled impeller performance. The analyzed results show that the critical fouled region associated with impeller performance degradations lies at the leading edge of blade tip. The SVR metamodel has been proved to be an efficient and accurate means in the detection of impeller performance variations caused by roughness uncertainties. After design optimization, the robust optimal design is found to be more efficient and less sensitive to fouling uncertainties while maintaining good impeller performance in the clean condition. This research proposes a systematic design optimization method for centrifugal compressors with considerations of blade fouling, providing a practical guidance to the design of advanced centrifugal compressors.

  3. Structural Changes in the Surface Layer of Deep Rolled Samples Due to Thermal Loads

    Directory of Open Access Journals (Sweden)

    Strunk, R

    2017-01-01

    Full Text Available Deep rolling processes initiate plastic deformations in the surface layer. The local characteristics of deformation are dependent on the induced stress expressed by the local stress tensor. Equivalent stresses above yield strength cause plastic deformation. Additionally the intrinsic energy, e. g. the dislocation density, is enhanced and the residual stress state is changed. The effects to a deep rolled surface from an increase in temperature are mainly dependent on the material, the microstructure, the initial residual stress state, the inclusion density, the distribution of soluted alloying elements and the plastic deformation. In the described experiments the interactions between deformation and temperature of the steel grade AISI 4140 (42 CrMo 4 used for all further experiments in a transregional Collaborative Research Center (CRC were to be examined. The most simple investigation methods were chosen deliberately to allow a better statistical support of correlations between introduced strains and material reactions for a wide variation of process parameters. Since the visual effects by light microscopy in AISI 4140 were very small, the experiments were repeated with german grade 18 CrNiMo 7-6 (comparable to AISI 4820. This paper focuses on the micro structural changes in defined deep rolled surface regions due to an increase in temperature. The work described is part of the Collaborative Research Center “Process Signatures”, collaboration between Bremen University, Technical University Aachen, Germany and Oklahoma State University Stillwater, USA.

  4. Errors of five-day mean surface wind and temperature conditions due to inadequate sampling

    Science.gov (United States)

    Legler, David M.

    1991-01-01

    Surface meteorological reports of wind components, wind speed, air temperature, and sea-surface temperature from buoys located in equatorial and midlatitude regions are used in a simulation of random sampling to determine errors of the calculated means due to inadequate sampling. Subsampling the data with several different sample sizes leads to estimates of the accuracy of the subsampled means. The number N of random observations needed to compute mean winds with chosen accuracies of 0.5 (N sub 0.5) and 1.0 (N sub 1,0) m/s and mean air and sea surface temperatures with chosen accuracies of 0.1 (N sub 0.1) and 0.2 (N sub 0.2) C were calculated for each 5-day and 30-day period in the buoy datasets. Mean values of N for the various accuracies and datasets are given. A second-order polynomial relation is established between N and the variability of the data record. This relationship demonstrates that for the same accuracy, N increases as the variability of the data record increases. The relationship is also independent of the data source. Volunteer-observing ship data do not satisfy the recommended minimum number of observations for obtaining 0.5 m/s and 0.2 C accuracy for most locations. The effect of having remotely sensed data is discussed.

  5. Seismic fragility analysis of typical pre-1990 bridges due to near- and far-field ground motions

    Science.gov (United States)

    Mosleh, Araliya; Razzaghi, Mehran S.; Jara, José; Varum, Humberto

    2016-03-01

    Bridge damages during the past earthquakes caused several physical and economic impacts to transportation systems. Many of the existing bridges in earthquake prone areas are pre-1990 bridges and were designed with out of date regulation codes. The occurrences of strong motions in different parts of the world show every year the vulnerability of these structures. Nonlinear dynamic time history analyses were conducted to assess the seismic vulnerability of typical pre-1990 bridges. A family of existing concrete bridge representative of the most common bridges in the highway system in Iran is studied. The seismic demand consists in a set of far-field and near-field strong motions to evaluate the likelihood of exceeding the seismic capacity of the mentioned bridges. The peak ground accelerations (PGAs) were scaled and applied incrementally to the 3D models to evaluate the seismic performance of the bridges. The superstructure was assumed to remain elastic and the nonlinear behavior in piers was modeled by assigning plastic hinges in columns. In this study the displacement ductility and the PGA are selected as a seismic performance indicator and intensity measure, respectively. The results show that pre-1990 bridges subjected to near-fault ground motions reach minor and moderate damage states.

  6. A Comprehensive Laboratory Study to Improve Ground Truth Calibration of Remotely Sensed Near-Surface Soil Moisture

    Science.gov (United States)

    Babaeian, E.; Tuller, M.; Sadeghi, M.; Sheng, W.; Jones, S. B.

    2016-12-01

    Optical satellite and airborne remote sensing (RS) have been widely applied for characterization of large-scale surface soil moisture distributions. However, despite the excellent spatial resolution of RS data, the electromagnetic radiation within the optical bands (400-2500 nm) penetrates the soil profile only to a depth of a few millimeters; hence obtained moisture estimates are limited to the soil surface region. Furthermore, moisture sensor networks employed for ground truth calibration of RS observations commonly exhibit very limited spatial resolution, which consequently leads to significant discrepancies between RS and ground truth observations. To better understand the relationship between surface and near-surface soil moisture, we employed a benchtop hyperspectral line-scan imaging system to generate high resolution surface reflectance maps during evaporation from soil columns filled with source soils covering a wide textural range and instrumented with a novel time domain reflectometry (TDR) sensor array that allows monitoring of near surface moisture at 0.5-cm resolution. A recently developed physical model for surface soil moisture predictions from shortwave infrared reflectance was applied to estimate surface soil moisture from surface reflectance and to explore the relationship between surface and near-surface moisture distributions during soil drying. Preliminary results are very promising and their applicability for ground truth calibration of RS observations will be discussed.

  7. Documentation of the Santa Clara Valley regional ground-water/surface-water flow model, Santa Clara Valley, California

    Science.gov (United States)

    Hanson, R.T.; Li, Zhen; Faunt, C.C.

    2004-01-01

    The Santa Clara Valley is a long, narrow trough extending about 35 miles southeast from the southern end of San Francisco Bay where the regional alluvial-aquifer system has been a major source of water. Intensive agricultural and urban development throughout the 20th century and related ground-water development resulted in ground-water-level declines of more than 200 feet and land subsidence of as much as 12.7 feet between the early 1900s and the mid-1960s. Since the 1960s, Santa Clara Valley Water District has imported surface water to meet growing demands and reduce dependence on ground-water supplies. This importation of water has resulted in a sustained recovery of the ground-water flow system. To help support effective management of the ground-water resources, a regional ground-water/surface-water flow model was developed. This model simulates the flow of ground water and surface water, changes in ground-water storage, and related effects such as land subsidence. A numerical ground-water/surface-water flow model of the Santa Clara Valley subbasin of the Santa Clara Valley was developed as part of a cooperative investigation with the Santa Clara Valley Water District. The model better defines the geohydrologic framework of the regional flow system and better delineates the supply and demand components that affect the inflows to and outflows from the regional ground-water flow system. Development of the model includes revisions to the previous ground-water flow model that upgraded the temporal and spatial discretization, added source-specific inflows and outflows, simulated additional flow features such as land subsidence and multi-aquifer wellbore flow, and extended the period of simulation through September 1999. The transient-state model was calibrated to historical surface-water and ground-water data for the period 197099 and to historical subsidence for the period 198399. The regional ground-water flow system consists of multiple aquifers that are grouped

  8. Interfaces Supporting Surface Gap Soliton Ground States in the 1D Nonlinear Schroedinger Equation

    CERN Document Server

    Dohnal, Tomas; Plum, Michael; Reichel, Wolfgang

    2012-01-01

    We consider the problem of verifying the existence of $H^1$ ground states of the 1D nonlinear Schr\\"odinger equation for an interface of two periodic structures: $$-u" +V(x)u -\\lambda u = \\Gamma(x) |u|^{p-1}u \\ {on} \\R$$ with $V(x) = V_1(x), \\Gamma(x)=\\Gamma_1(x)$ for $x\\geq 0$ and $V(x) = V_2(x), \\Gamma(x)=\\Gamma_2(x)$ for $x1$. The article [T. Dohnal, M. Plum and W. Reichel, "Surface Gap Soliton Ground States for the Nonlinear Schr\\"odinger Equation," \\textit{Comm. Math. Phys.} \\textbf{308}, 511-542 (2011)] provides in the 1D case an existence criterion in the form of an integral inequality involving the linear potentials $V_{1},V_2$ and the Bloch waves of the operators $-\\tfrac{d^2}{dx^2}+V_{1,2}-\\lambda$. We choose here the classes of piecewise constant and piecewise linear potentials $V_{1,2}$ and check this criterion for a set of parameter values. In the piecewise constant case the Bloch waves are calculated explicitly and in the piecewise linear case verified enclosures of the Bloch waves are computed ...

  9. Ground Plane and Near-Surface Thermal Analysis for NASA's Constellation Program

    Science.gov (United States)

    Gasbarre, Joseph F.; Amundsen, Ruth M.; Scola, Salvatore; Leahy, Frank F.; Sharp, John R.

    2008-01-01

    Most spacecraft thermal analysis tools assume that the spacecraft is in orbit around a planet and are designed to calculate solar and planetary fluxes, as well as radiation to space. On NASA Constellation projects, thermal analysts are also building models of vehicles in their pre-launch condition on the surface of a planet. This process entails making some modifications in the building and execution of a thermal model such that the radiation from the planet, both reflected albedo and infrared, is calculated correctly. Also important in the calculation of pre-launch vehicle temperatures are the natural environments at the vehicle site, including air and ground temperatures, sky radiative background temperature, solar flux, and optical properties of the ground around the vehicle. A group of Constellation projects have collaborated on developing a cohesive, integrated set of natural environments that accurately capture worst-case thermal scenarios for the pre-launch and launch phases of these vehicles. The paper will discuss the standardization of methods for local planet modeling across Constellation projects, as well as the collection and consolidation of natural environments for launch sites. Methods for Earth as well as lunar sites will be discussed.

  10. Two decades of temperature-time monitoring experiment: air - ground surface - shallow subsurface interactions

    Science.gov (United States)

    Cermak, Vladimir; Dedecek, Petr; Safanda, Jan; Kresl, Milan

    2014-05-01

    Long-term observations (1994-2013) of air and shallow ground temperatures at borehole Prague-Sporilov (50º02'28.5"E, 14º28'40.2"N, 274 m a.s.l.) have been thoroughly analyzed to understand the relationship between these quantities and to describe the mechanism of heat transport at the land-atmosphere boundary layer. Data provided a surprisingly small mean ground-air temperature offset of only 0.31 K with no clear annual course and with the offset value changing irregularly even on a daily scale. Such value is substantially lower than similar values (1-2 K and more) found elsewhere, but may well characterize a mild temperate zone, when all so far available information referred rather to southern locations. Borehole data were correlated with similar observations in a polygon-site under four types of surface conditions (grass, soil, sand and asphalt) completed with registration of meteorological variables (wind direction & velocity, air & soil humidity, direct & reflected solar radiation, precipitation and snow cover). The "thermal orbits" technique proved to be an effective tool for the fast qualitative diagnostics of the thermal regime in the subsurface (conductive versus non-conductive).

  11. Hydromechanical Simulations of Surface Uplift due to CO2 Injection at In Salah (Invited)

    Science.gov (United States)

    Morris, J. P.; Hao, Y.; Foxall, W.; McNab, W. W.

    2009-12-01

    . By including bounding faults into the model we achieve better agreement with the observed net uplift at the ground surface, but not the shape. However, by including flow into and pressurization of a hypothetical fault, our simulations better match the morphology of the surface deformation observed via InSAR. Our results indicate that the best fit is obtained through a combination of reservoir and fault pressurization (rather than either alone). However, our analysis had to make assumptions regarding the mechanical properties of the faults and the overburden. These results demonstrate that InSAR provides a powerful tool for gaining insight into fluid fate in the subsurface, but also highlight the need for detailed, accurate static geomodels. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Sampling and analysis for radon-222 dissolved in ground water and surface water

    Science.gov (United States)

    DeWayne, Cecil L.; Gesell, T.F.

    1992-01-01

    Radon-222 is a naturally occurring radioactive gas in the uranium-238 decay series that has traditionally been called, simply, radon. The lung cancer risks associated with the inhalation of radon decay products have been well documented by epidemiological studies on populations of uranium miners. The realization that radon is a public health hazard has raised the need for sampling and analytical guidelines for field personnel. Several sampling and analytical methods are being used to document radon concentrations in ground water and surface water worldwide but no convenient, single set of guidelines is available. Three different sampling and analytical methods - bubbler, liquid scintillation, and field screening - are discussed in this paper. The bubbler and liquid scintillation methods have high accuracy and precision, and small analytical method detection limits of 0.2 and 10 pCi/l (picocuries per liter), respectively. The field screening method generally is used as a qualitative reconnaissance tool.

  13. Surface Properties and Characteristics of Mars Landing Sites from Remote Sensing Data and Ground Truth

    Science.gov (United States)

    Golombek, M. P.; Haldemann, A. F.; Simpson, R. A.; Furgason, R. L.; Putzig, N. E.; Huertas, A.; Arvidson, R. E.; Heet, T.; Bell, J. F.; Mellon, M. T.; McEwen, A. S.

    2008-12-01

    Surface characteristics at the six sites where spacecraft have successfully landed on Mars can be related favorably to their signatures in remotely sensed data from orbit and from the Earth. Comparisons of the rock abundance, types and coverage of soils (and their physical properties), thermal inertia, albedo, and topographic slope all agree with orbital remote sensing estimates and show that the materials at the landing sites can be used as ground truth for the materials that make up most of the equatorial and mid- to moderately high-latitude regions of Mars. The six landing sites sample two of the three dominant global thermal inertia and albedo units that cover ~80% of the surface of Mars. The Viking, Spirit, Mars Pathfinder, and Phoenix landing sites are representative of the moderate to high thermal inertia and intermediate to high albedo unit that is dominated by crusty, cloddy, blocky or frozen soils (duricrust that may be layered) with various abundances of rocks and bright dust. The Opportunity landing site is representative of the moderate to high thermal inertia and low albedo surface unit that is relatively dust free and composed of dark eolian sand and/or increased abundance of rocks. Rock abundance derived from orbital thermal differencing techniques in the equatorial regions agrees with that determined from rock counts at the surface and varies from ~3-20% at the landing sites. The size-frequency distributions of rocks >1.5 m diameter fully resolvable in HiRISE images of the landing sites follow exponential models developed from lander measurements of smaller rocks and are continuous with these rock distributions indicating both are part of the same population. Interpretation of radar data confirms the presence of load bearing, relatively dense surfaces controlled by the soil type at the landing sites, regional rock populations from diffuse scattering similar to those observed directly at the sites, and root-mean-squared slopes that compare favorably

  14. Ground Boundary Conditions for Thermal Convection Over Horizontal Surfaces at High Rayleigh Numbers

    Science.gov (United States)

    Hanjalić, K.; Hrebtov, M.

    2016-07-01

    We present "wall functions" for treating the ground boundary conditions in the computation of thermal convection over horizontal surfaces at high Rayleigh numbers using coarse numerical grids. The functions are formulated for an algebraic-flux model closed by transport equations for the turbulence kinetic energy, its dissipation rate and scalar variance, but could also be applied to other turbulence models. The three-equation algebraic-flux model, solved in a T-RANS mode ("Transient" Reynolds-averaged Navier-Stokes, based on triple decomposition), was shown earlier to reproduce well a number of generic buoyancy-driven flows over heated surfaces, albeit by integrating equations up to the wall. Here we show that by using a set of wall functions satisfactory results are found for the ensemble-averaged properties even on a very coarse computational grid. This is illustrated by the computations of the time evolution of a penetrative mixed layer and Rayleigh-Bénard (open-ended, 4:4:1 domain) convection, using 10 × 10 × 100 and 10 × 10 × 20 grids, compared also with finer grids (e.g. 60 × 60 × 100), as well as with one-dimensional treatment using 1 × 1 × 100 and 1 × 1 × 20 nodes. The approach is deemed functional for simulations of a convective boundary layer and mesoscale atmospheric flows, and pollutant transport over realistic complex hilly terrain with heat islands, urban and natural canopies, for diurnal cycles, or subjected to other time and space variations in ground conditions and stratification.

  15. MHD Homogeneous-Heterogeneous Reactions in a Nanofluid due to a Permeable Shrinking Surface

    Directory of Open Access Journals (Sweden)

    Syahira Mansur

    2016-01-01

    Full Text Available The MHD homogeneous-heterogeneous reaction in a nanofluid flow due to a permeable shrinking surface is studied. The bvp4c program in MATLAB is used to obtain the numerical solutions for several values of parameters such as suction parameter, magnetic parameter, nanoparticle volume fraction, heterogeneous reaction and homogeneous reaction rates. The results show that dual solutions exist and the magnetic parameter and the nanoparticle volume fraction widen the range of the solution domain. Suction parameter, magnetic parameter and nanoparticle volume fraction cause the skin friction coefficient to increase and the velocity to decrease. The concentration increases as the nanoparticle volume fraction increases but decrease as the homogeneous reaction rate and heterogeneous reaction rate increase.

  16. Changes in extreme regional sea surface height due to an abrupt weakening of the Atlantic MOC

    Directory of Open Access Journals (Sweden)

    S.-E. Brunnabend

    2014-04-01

    Full Text Available As an extreme scenario of dynamical sea level changes, regional sea surface height (SSH changes that occur in the North Atlantic due to an abrupt weakening of the Atlantic Meridional Overturning Circulation (AMOC are simulated. Two versions of the same ocean-only model are used to study the effect of ocean model resolution on these SSH changes: a high-resolution (HR strongly eddying version and a low-resolution (LR version in which the effect of eddies are parameterized. The weakening of the AMOC is induced in both model versions by applying strong freshwater perturbations around Greenland. A rapid decrease of the AMOC in the HR version induces much shorter return times of several specific regional and coastal extremes in North Atlantic SSH than in the LR version. This effect is caused by a change in main eddy pathways associated with a change in separation latitude of the Gulf Stream.

  17. ANALYSIS OF HIGH FIELD NON-LINEAR LOSSES ON SRF SURFACES DUE TO SPECIFIC TOPOGRAPHIC ROUGHNESS

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xu,Charles Reece,Michael Kelley

    2012-07-01

    The high-field performance of SRF cavities will eventually be limited by the realization of fundamental material limits, whether it is Hc1 or Hsh, or some derivative thereof, at which the superconductivity is lost. Before reaching this fundamental field limit at the macro level, it must be encountered at localized, perhaps microscopic, sites of field enhancement due to local topography. If such sites are small enough, they may produce thermally stabilized normal-conducting regions which contribute non-linear losses when viewed from the macro resonant field perspective, and thus produce degradation in Q0. We have undertaken a calculation of local surface magnetic field enhancement from specific fine topographic structure by conformal mapping method and numerically. A solution of the resulting normal conducting volume has been derived and the corresponding RF Ohmic loss simulated.

  18. Scalable and Detail-Preserving Ground Surface Reconstruction from Large 3D Point Clouds Acquired by Mobile Mapping Systems

    Science.gov (United States)

    Craciun, D.; Serna Morales, A.; Deschaud, J.-E.; Marcotegui, B.; Goulette, F.

    2014-08-01

    The currently existing mobile mapping systems equipped with active 3D sensors allow to acquire the environment with high sampling rates at high vehicle velocities. While providing an effective solution for environment sensing over large scale distances, such acquisition provides only a discrete representation of the geometry. Thus, a continuous map of the underlying surface must be built. Mobile acquisition introduces several constraints for the state-of-the-art surface reconstruction algorithms. Smoothing becomes a difficult task for recovering sharp depth features while avoiding mesh shrinkage. In addition, interpolation-based techniques are not suitable for noisy datasets acquired by Mobile Laser Scanning (MLS) systems. Furthermore, scalability is a major concern for enabling real-time rendering over large scale distances while preserving geometric details. This paper presents a fully automatic ground surface reconstruction framework capable to deal with the aforementioned constraints. The proposed method exploits the quasi-flat geometry of the ground throughout a morphological segmentation algorithm. Then, a planar Delaunay triangulation is applied in order to reconstruct the ground surface. A smoothing procedure eliminates high frequency peaks, while preserving geometric details in order to provide a regular ground surface. Finally, a decimation step is applied in order to cope with scalability constraints over large scale distances. Experimental results on real data acquired in large urban environments are presented and a performance evaluation with respect to ground truth measurements demonstrate the effectiveness of our method.

  19. Temperature dependent surface modification of molybdenum due to low energy He{sup +} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, J.K., E-mail: jtripat@purdue.edu [Center for Materials Under Extreme Environment (CMUXE), School of Nuclear Engineering, Purdue University, West Lafayette, IN 47907 (United States); Novakowski, T.J.; Joseph, G. [Center for Materials Under Extreme Environment (CMUXE), School of Nuclear Engineering, Purdue University, West Lafayette, IN 47907 (United States); Linke, J. [Forschungszentrum Jülich GmbH, EURATOM Association, Jülich D-52425 (Germany); Hassanein, A. [Center for Materials Under Extreme Environment (CMUXE), School of Nuclear Engineering, Purdue University, West Lafayette, IN 47907 (United States)

    2015-09-15

    In this paper, we report on the temperature dependent surface modifications in molybdenum (Mo) samples due to 100 eV He{sup +} ion irradiation in extreme conditions as a potential candidate to plasma-facing components in fusion devices alternative to tungsten. The Mo samples were irradiated at normal incidence, using an ion fluence of 2.6 × 10{sup 24} ions m{sup −2} (with a flux of 7.2 × 10{sup 20} ions m{sup −2} s{sup −1}). Surface modifications have been studied using high-resolution field emission scanning electron-(SEM) and atomic force (AFM) microscopy. At 773 K target temperature homogeneous evolution of molybdenum nanograins on the entire Mo surface were observed. However, at 823 K target temperature appearance of nano-pores and pin-holes nearby the grain boundaries, and Mo fuzz in patches were observed. The fuzz density increases significantly with target temperatures and continued until 973 K. However, at target temperatures beyond 973 K, counterintuitively, a sequential reduction in the fuzz density has been seen till 1073 K temperatures. At 1173 K and above temperatures, only molybdenum nano structures were observed. Our temperature dependent studies confirm a clear temperature widow, 823–1073 K, for Mo fuzz formation. Ex-situ high resolution X-ray photoelectron spectroscopy studies on Mo fuzzy samples show the evidence of MoO{sub 3} 3d doublets. This elucidates that almost all the Mo fuzz were oxidized during open air exposure and are thick enough as well. Likewise the microscopy studies, the optical reflectivity measurements also show a sequential reduction in the reflectivity values (i.e., enhancement in the fuzz density) up to 973 K and after then a sequential enhancement in the reflectivity values (i.e., reduction in the fuzz density) with target temperatures. This is in well agreement with microscopy studies where we observed clear temperature window for Mo fuzz growth.

  20. Wind flow modulation due to variations of the water surface roughness

    Science.gov (United States)

    Shomina, Olga; Ermakov, Stanislav; Kapustin, Ivan; Lazareva, Tatiana

    2016-04-01

    Air-ocean interaction is a classical problem in atmosphere and ocean physics, which has important geophysical applications related to calculation of vertical and horizontal humidity, aerosol and gas fluxes, development of global climate models and weather forecasts. The structure of wind flow over fixed underlying surfaces, such as forestry, buildings, mountains, is well described, while the interaction between a rough water surface and turbulent wind is far more complicated because of the presence of wind waves with different wavelength and amplitudes and propagating with different velocities and directions. The aim of this study was to investigate experimentally the variability of the wind profile structure due to variations of wave characteristics. The surface roughness variations were produced using a) surfactant films (oleic acid) spread on the water surface and b) mechanically generated waves superimposed on wind waves. The first case is related to oil slicks on sea surface, the second one - to the sea swell, which propagates into zones with lower wind velocities and interacts with wind flow. Laboratory experiments were conducted in the Oval Wind Wave Tank (OWWT) at the Institute of Applied Physics, cross-section of the wind channel is 30 cm x30 cm. Wave amplitude and the spectrum of surface waves were measured by a wire wave gauge, the wind speed was measured using a hot-wire anemometer DISA and a Pitot tube. In the experiments with surfactants, two frequencies of dripping of the oleic acid were studied, so that low concentration films with the elasticity parameters of about 19 mN/m and the high concentration ("thick") films with the elasticity of 34 mN/m were formed. In the experiments with mechanically generated waves (MGW) different regimes were studied with MGW amplitude of 3.4 mm and of 4.4 mm, and with MGW frequencies of 3.3 Hz and 3.7 Hz. It was shown, that: a) the mean velocity of the wind flow in the presence of surfactant and MGW can be described

  1. Characterization of the Aerodynamic Ground Effect and Its Influence in Multirotor Control

    National Research Council Canada - National Science Library

    Pedro Sanchez-Cuevas; Guillermo Heredia; Anibal Ollero

    2017-01-01

    This paper analyzes the ground effect in multirotors, that is, the change in the thrust generated by the rotors when flying close to the ground due to the interaction of the rotor airflow with the ground surface...

  2. Atrazine and its degradation products in surface and ground waters in Zhangjiakou District, China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A method using the solid phase extraction (SPE) and liquid chromatography-mass spectrometry (LC-MS) to analyse atrazine and its degradation products at levels of low nanograms per liter in water has been developed. The environmental water samples were filtered and then extracted by SPE with a new sulfonation of poly(divinylbenzene-co-N- vinylpyrrolidone) sorbents MCX. HPLC/APCIMS was used for the analysis of atrazine and its degradation products, desethylatrazine (DEA), deisopropylatrazine (DIA), didealkylatrazine (DEDIA), and hydroxyatrazine (HYA). The detection limits ranged from 10-50 ng/L in water samples. Samples were collected from deep wells and a reservoir near a plant that produced atrazine. Atrazine concentration levels in most surface samples were above the limit of the China Surface Water Regulation (3 mg/L). In ground water, the levels of degradation product were more than 0.1 mg/L and 5-10 times greater than those of atrazine. The highest DEA concentration in the groundwater sample taken at the 130 m depth was 7.2 ug/L.

  3. Spectroscopic determination of ground and excited state vibrational potential energy surfaces

    Science.gov (United States)

    Laane, Jaan

    Far-infrared spectra, mid-infrared combination band spectra, Raman spectra, and dispersed fluorescence spectra of non-rigid molecules can be used to determine the energies of many of the quantum states of conformationally important vibrations such as out-of-plane ring modes, internal rotations, and molecular inversions in their ground electronic states. Similarly, the fluorescence excitation spectra of jet-cooled molecules, together with electronic absorption spectra, provide the information for determining the vibronic energy levels of electronic excited states. One- or two-dimensional potential energy functions, which govern the conformational changes along the vibrational coordinates, can be determined from these types of data for selected molecules. From these functions the molecular structures, the relative energies between different conformations, the barriers to molecular interconversions, and the forces responsible for the structures can be ascertained. This review describes the experimental and theoretical methodology for carrying out the potential energy determinations and presents a summary of work that has been carried out for both electronic ground and excited states. The results for the out-of-plane ring motions of four-, five-, and six-membered rings will be presented, and results for several molecules with unusual properties will be cited. Potential energy functions for the carbonyl wagging and ring modes for several cyclic ketones in their S1(n,pi*) states will also be discussed. Potential energy surfaces for the three internal rotations, including the one governing the photoisomerization process, will be examined for trans-stilbene in both its S0 and S1(pi,pi*) states. For the bicyclic molecules in the indan family, the two-dimensional potential energy surfaces for the highly interacting ring-puckering and ring-flapping motions in both the S0 and S1(pi,pi*) states have also been determined using all of the spectroscopic methods mentioned above

  4. Ozone treatment of coal- and coffee grounds-based active carbons: Water vapor adsorption and surface fractal micropores

    Energy Technology Data Exchange (ETDEWEB)

    Tsunoda, Ryoichi; Ozawa, Takayoshi; Ando, Junichi [Kanagawa Industrial Technology Research Inst., Ebina, Kanagawa (Japan)

    1998-09-15

    Characteristics of the adsorption iostherms of water vapor on active carbons from coal and coffee grounds and those ozonized ones from the surface fractal dimension analysis are discussed. The upswing of the adsorption isotherms in the low relative pressure of coffee grounds-based active carbon, of which isotherms were not scarcely affected on ozonization, was attributed to the adsorption of water molecules on the metallic oxides playing the role of oxygen-surface complexes, which formed the corrugated surfaces on the basal planes of micropore walls with the surface fractal dimension D{sub s} > 2. On the other hand, coal-based active carbon with D{sub s} < 2, which indicated the flat surfaces of micropore walls, showed little effect on the upswing even on ozonization, even though the adsorption amounts of water vapor were increased in the low relative pressure.

  5. Groundwater Surface Trends at Van Norden Meadow, California, from Ground Penetrating Radar Profiles

    Science.gov (United States)

    Tadrick, N. I.; Blacic, T. M.; Yarnell, S. M.

    2014-12-01

    Van Norden meadow in the Donner Summit area west of Lake Tahoe is one of the largest sub-alpine meadows in the Sierra Nevada mountain range. As natural water retention basins, meadows attenuate floods, improve water quality and support vegetation that stabilizes stream banks and promotes high biodiversity. Like most meadows in the Sierras however, over-grazing, road-building, and development has resulted in localized stream incision, degradation, and partial conversion from wet to dry conditions in Van Norden. Additionally, a small dam at the base of the meadow has partially flooded the lower meadow creating reservoir conditions. Privately owned since the late 1800s, Van Norden was recently purchased by a local land trust to prevent further development and return the area to public ownership. Restoration of the natural meadow conditions will involve notching the dam in 2016 to reduce currently impounded water volumes from 250 to less than 50 acre-feet. To monitor the effects of notching the dam on the upstream meadow conditions, better understanding of the surface and groundwater hydrology both pre- and post-restoration is required. We surveyed the meadow in summer 2014 with ground penetrating radar (GPR) to map the groundwater surface prior to restoration activities using a 270MHz antenna to obtain a suite of longitudinal and transverse transects. Groundwater level within the meadow was assessed using both piezometer readings and sweeps of the GPR antenna. Seventeen piezometers were added this year to the 13 already in place to monitor temporal changes in the groundwater surface, while the GPR profiles provided information about lateral variations. Our results provide an estimate of the groundwater depth variations across the upper portion of the meadow before notching. We plan to return in 2015 to collect GPR profiles during wetter conditions, which will provide a more complete assessment of the pre-notching groundwater hydrology.

  6. Surface Nuclear Magnetic Resonance (SNMR - A new method for exploration of ground water and aquifer properties

    Directory of Open Access Journals (Sweden)

    U. Yaramanci

    2000-06-01

    Full Text Available The Surface Nuclear Magnetic Resonance (SNMR method is a fairly new technique in geophysics to assess ground water, i.e. existence, amount and productibility by measurements at the surface. The NMR technique used in medicine, physics and lately in borehole geophysics was adopted for surface measurements in the early eighties, and commercial equipment for measurements has been available since the mid nineties. The SNMR method has been tested at sites in Northern Germany with Quaternary sand and clay layers, to examine the suitability of this new method for groundwater exploration and environmental investigations. More information is obtained by SNMR, particularly with respect to aquifer parameters, than with other geophysical techniques. SNMR measurements were carried out at three borehole locations, together with 2D and 1D direct current geoelectrics and well logging (induction log, gamma-ray log and pulsed neutron-gamma log. Permeabilities were calculated from the grain-size distributions of core material determined in the laboratory. It is demonstrated that the SNMR method is able to detect groundwater and the results are in good agreement with other geophysical and hydrogeological data. Using the SNMR method, the water content of the unsaturated and saturated zones (i.e. porosity of an aquifer can be reliably determined. This information and resistivity data permit in-situ determination of other aquifer parameters. Comparison of the SNMR results with borehole data clearly shows that the water content determined by SNMR is the free or mobile water in the pores. The permeabilities estimated from the SNMR decay times are similar to those derived from sieve analysis of core material. Thus, the combination of SNMR with geoelectric methods promises to be a powerful tool for studying aquifer properties.

  7. Transport and fate of nitrate at the ground-water/surface-water interface

    Science.gov (United States)

    Puckett, L.J.; Zamora, C.; Essaid, H.; Wilson, J.T.; Johnson, H.M.; Brayton, M.J.; Vogel, J.R.

    2008-01-01

    Although numerous studies of hyporheic exchange and denitrification have been conducted in pristine, high-gradient streams, few studies of this type have been conducted in nutrient-rich, low-gradient streams. This is a particularly important subject given the interest in nitrogen (N) inputs to the Gulf of Mexico and other eutrophic aquatic systems. A combination of hydrologic, mineralogical, chemical, dissolved gas, and isotopic data, were used to determine the processes controlling transport and fate of NO3- in streambeds at five sites across the USA. Water samples were collected from streambeds at depths ranging from 0.3 to 3 m at three to five points across the stream and in two to five separate transects. Residence times of water ranging from 0.28 to 34.7 d m-1 in the streambeds of N-rich watersheds played an important role in allowing denitrification to decrease NO3- concentrations. Where potential electron donors were limited and residence times were short, denitrification was limited. Consequently, in spite of reducing conditions at some sites, NO3- was transported into the stream. At two of the five study sites, NO3- in surface water infiltrated the streambeds and concentrations decreased, supporting current models that NO3- would be retained in N-rich streams. At the other three study sites, hydrogeologic controls limited or prevented infiltration of surface water into the streambed, and ground-water discharge contributed to NO 3- loads. Our results also show that in these low hydrologic-gradient systems, storm and other high-flow events can be important factors for increasing surface-water movement into streambeds. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  8. A comparative study of the phosphate levels in some surface and ground water bodies of Swaziland

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    A.O. Fadiran

    2008-08-01

    Full Text Available The levels of total phosphate in selected surface water and groundwater bodies from Manzini and Lubombo regions of Swaziland were determined using UV spectroscopic method. Samples were collected from three rivers (upstream and downstream of each, three industrial effluents, one reservoir, one pond, one tap water and fifteen boreholes. Mean phosphate levels in the tap water and reservoir varied between 0.08-0.09 mg/L while for the river samples, the range was 0.11-0.37 and for the industrial discharge, it was 0.11-1.60 mg/L PO4–P. For the ground water systems it ranged between 0.10-0.49 mg/L PO4–P. The mean phosphate levels in all the analyzed surface and groundwater samples were below the recommended maximum contaminant level (MCL by SWSC (Swaziland Water Service Corporation – i.e. 1.0 mg/L for drinking water; 2.0 mg/L for rivers and industrial effluents, and the South African criterion of 1.0 mg/L PO4–P, for sewage effluents being discharged into receiving waters. However, pooled mean values for all the sites were higher than the USEPA criterion of 0.03 mg/L maximum for uncontaminated lakes. Dominant factors considered to have influenced the levels of phosphates in both the surface and groundwater samples analyzed include industrial activities (where present, agricultural activities (including livestock, population density, location (urban, suburban or rural, soil/rock type in the vicinity of the sampling point, climate and rainfall pattern of the area or region concerned.

  9. Pendulating—A grounded theory explaining patients’ behavior shortly after having a leg amputated due to vascular disease

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    Ulla Riis Madsen

    2016-09-01

    Full Text Available Introduction: Although the group of vascular leg amputated patients constitutes some of the most vulnerable and frail on the orthopedic wards, previous research of amputated patients has focused on patients attending gait training in rehabilitation facilities leaving the patient experience shortly after surgery unexplored. Understanding patients’ behavior shortly after amputation could inform health professionals in regard to how these vulnerable patients’ needs at hospital can be met as well as how to plan for care post-discharge. Aim: To construct a grounded theory (GT explaining patients’ behavior shortly after having a leg amputated as a result of vascular disease. Method: In line with constructivist GT methodology, data from ethnographic observations and interviews were simultaneously collected and analyzed using the constant comparative method covering the patients’ experiences during the first 4 weeks post-surgery. Data collection was guided by theoretical sampling and comprised 11 patients. A GT was constructed. Results: Patients went through a three-phased process as they realized they were experiencing a life-changing event. The first phase was “Losing control” and comprised the sub-categories “Being overwhelmed” and “Facing dependency.” The second phase was “Digesting the shock” and comprised the sub-categories “Swallowing the life-changing decision,” “Detecting the amputated body” and “Struggling dualism.” The third phase was “Regaining control” and comprised the sub-categories “Managing consequences” and “Building-up hope and self-motivation.” “Pendulating” was identified as the core category describing the general pattern of behavior and illustrated how patients were swinging both cognitively and emotionally throughout the process. Conclusion: The theory of “Pendulating” offers a tool to understand the amputated patients’ behavior and underlying concerns and to recognize

  10. Pendulating—A grounded theory explaining patients’ behavior shortly after having a leg amputated due to vascular disease

    Science.gov (United States)

    Madsen, Ulla Riis; Hommel, Ami; Bååth, Carina; Berthelsen, Connie Bøttcher

    2016-01-01

    Introduction Although the group of vascular leg amputated patients constitutes some of the most vulnerable and frail on the orthopedic wards, previous research of amputated patients has focused on patients attending gait training in rehabilitation facilities leaving the patient experience shortly after surgery unexplored. Understanding patients’ behavior shortly after amputation could inform health professionals in regard to how these vulnerable patients’ needs at hospital can be met as well as how to plan for care post-discharge. Aim To construct a grounded theory (GT) explaining patients’ behavior shortly after having a leg amputated as a result of vascular disease. Method In line with constructivist GT methodology, data from ethnographic observations and interviews were simultaneously collected and analyzed using the constant comparative method covering the patients’ experiences during the first 4 weeks post-surgery. Data collection was guided by theoretical sampling and comprised 11 patients. A GT was constructed. Results Patients went through a three-phased process as they realized they were experiencing a life-changing event. The first phase was “Losing control” and comprised the sub-categories “Being overwhelmed” and “Facing dependency.” The second phase was “Digesting the shock” and comprised the sub-categories “Swallowing the life-changing decision,” “Detecting the amputated body” and “Struggling dualism.” The third phase was “Regaining control” and comprised the sub-categories “Managing consequences” and “Building-up hope and self-motivation.” “Pendulating” was identified as the core category describing the general pattern of behavior and illustrated how patients were swinging both cognitively and emotionally throughout the process. Conclusion The theory of “Pendulating” offers a tool to understand the amputated patients’ behavior and underlying concerns and to recognize where they are in the

  11. Questa baseline and pre-mining ground-water quality investigation. 10. Geologic influences on ground and surface waters in the lower Red River watershed, New Mexico

    Science.gov (United States)

    Ludington, Steve; Plumlee, Geoff; Caine, Jonathan; Bove, Dana; Holloway, JoAnn; Livo, Eric

    2005-01-01

    Introduction: This report is one in a series that presents results of an interdisciplinary U.S. Geological Survey (USGS) study of ground-water quality in the lower Red River watershed prior to open-pit and underground molybdenite mining at Molycorp's Questa mine. The stretch of the Red River watershed that extends from just upstream of the town of Red River, N. Mex., to just above the town of Questa includes several mineralized areas in addition to the one mined by Molycorp. Natural erosion and weathering of pyrite-rich rocks in the mineralized areas has created a series of erosional scars along this stretch of the Red River that contribute acidic waters, as well as mineralized alluvial material and sediments, to the river. The overall goal of the USGS study is to infer the premining ground-water quality at the Molycorp mine site. An integrated geologic, hydrologic, and geochemical model for ground water in the mineralized-but unmined-Straight Creek drainage (a tributary of the Red River) is being used as an analog for the geologic, geochemical, and hydrologic conditions that influenced ground-water quality and quantity in the Red River drainage prior to mining. This report provides an overall geologic framework for the Red River watershed between Red River and Questa, in northern New Mexico, and summarizes key geologic, mineralogic, structural and other characteristics of various mineralized areas (and their associated erosional scars and debris fans) that likely influence ground- and surface-water quality and hydrology. The premining nature of the Sulphur Gulch and Goat Hill Gulch scars on the Molycorp mine site can be inferred through geologic comparisons with other unmined scars in the Red River drainage.

  12. A mixed space-time and wavenumber-frequency domain procedure for modelling ground vibration from surface railway tracks

    Science.gov (United States)

    Koroma, S. G.; Thompson, D. J.; Hussein, M. F. M.; Ntotsios, E.

    2017-07-01

    This paper presents a methodology for studying ground vibration in which the railway track is modelled in the space-time domain using the finite element method (FEM) and, for faster computation, discretisation of the ground using either FEM or the boundary element method (BEM) is avoided by modelling it in the wavenumber-frequency domain. The railway track is coupled to the ground through a series of rectangular strips located at the surface of the ground; their vertical interaction is described by a frequency-dependent dynamic stiffness matrix whose elements are represented by discrete lumped parameter models. The effectiveness of this approach is assessed firstly through frequency domain analysis using as excitation a stationary harmonic load applied on the rail. The interaction forces at the ballast/ground interface are calculated using the FE track model in the space-time domain, transformed to the wavenumber domain, and used as input to the ground model for calculating vibration in the free field. Additionally, time domain simulations are also performed with the inclusion of nonlinear track parameters. Results are presented for the coupled track/ground model in terms of time histories and frequency spectra for the track vibration, interaction forces and free-field ground vibration. For the linear track model, the results from the mixed formulation are in excellent agreement with those from a semi-analytical model formulated in the wavenumber-frequency domain, particularly in the vicinity of the loading point. The accuracy of the mixed formulation away from the excitation point depends strongly on the inclusion of through-ground coupling in the lumped parameter model, which has been found to be necessary for both track dynamics and ground vibration predictions.

  13. Ground surface temperature histories in northern Ontario and Québec for the past 500 years

    Science.gov (United States)

    Pickler, Carolyne; Beltrami, Hugo; Mareschal, Jean-Claude

    2016-04-01

    We have used 19 temperature-depth profiles measured in boreholes from eastern Canada to reconstruct the ground surface temperature histories of the region. The boreholes are located north of 51oN, and west and east of James Bay in northern Ontario and Québec. The 8 boreholes in northern Ontario come from 3 sites in a region of extensive discontinuous permafrost, while the 11 holes from Québec come from 6 sites in a region of sporadic discontinuous permafrost. The depths of the holes range between 400 and 800 m, allowing a reconstruction of the ground surface temperature histories for the past 500 years. Present ground surface temperatures are higher in Québec, perhaps because the region receives more snowfall as shown by meteorological records and proxy data. The ground surface temperature histories indicate a present-day warming of ˜2-2.5oC in Ontario and ˜1-1.5oC in Québec relative to the reference surface temperature 500 years BP. These results are in agreement with available proxy data for the recent warming in eastern North America. Furthermore, they suggest that the higher snowfall and strong cooling during the Little Ice Age could have muted the borehole temperature record of climate change in Québec.

  14. An Upscaling Algorithm to Obtain the Representative Ground Truth of LAI Time Series in Heterogeneous Land Surface

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    Yuechan Shi

    2015-09-01

    Full Text Available Upscaling in situ leaf area index (LAI measurements to the footprint scale is important for the validation of medium resolution remote sensing products. However, surface heterogeneity and temporal variation of vegetation make this difficult. In this study, a two-step upscaling algorithm was developed to obtain the representative ground truth of LAI time series in heterogeneous surfaces based on in situ LAI data measured by the wireless sensor network (WSN observation system. Since heterogeneity within a site usually arises from the mixture of vegetation and non-vegetation surfaces, the spatial heterogeneity of vegetation and land cover types were separately considered. Representative LAI time series of vegetation surfaces were obtained by upscaling in situ measurements using an optimal weighted combination method, incorporating the expectation maximum (EM algorithm to derive the weights. The ground truth of LAI over the whole site could then be determined using area weighted combination of representative LAIs of different land cover types. The algorithm was evaluated using a dataset collected in Heihe Watershed Allied Telemetry Experimental Research (HiWater experiment. The proposed algorithm can effectively obtain the representative ground truth of LAI time series in heterogeneous cropland areas. Using the normal method of an average LAI measurement to represent the heterogeneous surface produced a root mean square error (RMSE of 0.69, whereas the proposed algorithm provided RMSE = 0.032 using 23 sampling points. The proposed ground truth derived method was implemented to validate four major LAI products.

  15. Microstructural changes due to laser surface melting of an AISI 304 stainless steel

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    d?Oliveira A.S.C.M.

    2001-01-01

    Full Text Available Several techniques can be used to improve surface properties. These can involve changes on the surface chemical composition (such as alloying and surface welding processes or on the surface microstructure, such as hardening and melting. In the present work surface melting with a 3kW CO2 cw laser was done to alter surface features of an AISI 304 stainless steel. Microstructure characterisation was done by optical and scanning electron microscopy. Vickers and Knoop microhardness tests evaluated mechanical features after surface melting. Phase transformation during rapid solidification is analysed and discussed.

  16. Geocenter motion due to surface mass transport from GRACE satellite data

    Science.gov (United States)

    Riva, R. E. M.; van der Wal, W.; Lavallée, D. A.; Hashemi Farahani, H.; Ditmar, P.

    2012-04-01

    Measurements of mass redistribution from satellite gravimetry are insensitive to geocenter motions. However, geocenter motions can be constrained by satellite gravity data alone if we partition mass changes between land and oceans, under the assumption that the ocean is passive (i.e., in gravitational equilibrium with the land load and the solid earth). Here, we make use of 8 years (2003-2010) of optimally filtered monthly GRACE-based solutions produced at TU Delft to determine changes in the land load and the corresponding geocenter motion, through an iterative procedure. We pay particular attention to correcting for signal leakage caused by the limited spatial resolution of GRACE. We also investigate how the choice of a model of glacial isostatic adjustment (GIA) affects the estimated geocenter motion trend due to present-day surface mass transport. Finally, we separate the contribution of ice masses from that of land hydrology and show how they have a different sensitivity to the chosen GIA model and observational time-span.

  17. A universal salt model based on under-ground precipitation of solid salts due to supercritical water `out-salting'

    Science.gov (United States)

    Rueslåtten, H.; Hovland, M. T.

    2010-12-01

    One of the common characteristics of planets Earth and Mars is that both host water (H2O) and large accumulations of salt. Whereas Earth’s surface-environment can be regarded as ‘water-friendly’ and ‘salt hostile’, the reverse can be said for the surface of Mars. This is because liquid water is stable on Earth, and the atmosphere transports humidity around the globe, whereas on planet Mars, liquid water is unstable, rendering the atmosphere dry and, therefore, ‘salt-friendly’. The riddle as to how the salt accumulated in various locations on those two planets, is one of long-lasting and great debate. The salt accumulations on Earth are traditionally termed ‘evaporites’, meaning that they formed as a consequence of the evaporation of large masses of seawater. How the accumulations on Mars formed is much harder to explain, as an ocean only existed briefly. Although water molecules and OH-groups may exist in abundance in bound form (crystal water, adsorbed water, etc.), the only place where free water is expected to be stable on Mars is within underground faults, fractures, and crevices. Here it likely occurs as brine or in the form of ice. Based on these conditions, a key to understanding the accumulation of large deposits of salt on both planets is linked to how brines behave in the subsurface when pressurized and heated beyond their supercritical point. At depths greater than about 3 km (P>300 bars) water will no longer boil in a steam phase. Rather, it becomes supercritical and will attain the phase of supercritical water vapor (SCRIW) with a specific gravity of typically 0.3 g/cm3. An important characteristic of SCRIW is its inability to dissolve the common sea salts. The salt dissolved in the brines will therefore precipitate as solid particles when brines (seawater on the Earth) move into the supercritical P&T-domain (T>400°C, P>300 bars). Numerical modeling of a hydrothermal system in the Atlantis II Deep of the Red Sea indicates that a

  18. Simulation of ground-water/surface-water flow in the Santa Clara-Calleguas ground-water basin, Ventura County, California

    Science.gov (United States)

    Hanson, Randall T.; Martin, Peter; Koczot, Kathryn M.

    2003-01-01

    Ground water is the main source of water in the Santa Clara-Calleguas ground-water basin that covers about 310 square miles in Ventura County, California. A steady increase in the demand for surface- and ground-water resources since the late 1800s has resulted in streamflow depletion and ground-water overdraft. This steady increase in water use has resulted in seawater intrusion, inter-aquifer flow, land subsidence, and ground-water contamination. The Santa Clara-Calleguas Basin consists of multiple aquifers that are grouped into upper- and lower-aquifer systems. The upper-aquifer system includes the Shallow, Oxnard, and Mugu aquifers. The lower-aquifer system includes the upper and lower Hueneme, Fox Canyon, and Grimes Canyon aquifers. The layered aquifer systems are each bounded below by regional unconformities that are overlain by extensive basal coarse-grained layers that are the major pathways for ground-water production from wells and related seawater intrusion. The aquifer systems are bounded below and along mountain fronts by consolidated bedrock that forms a relatively impermeable boundary to ground-water flow. Numerous faults act as additional exterior and interior boundaries to ground-water flow. The aquifer systems extend offshore where they crop out along the edge of the submarine shelf and within the coastal submarine canyons. Submarine canyons have dissected these regional aquifers, providing a hydraulic connection to the ocean through the submarine outcrops of the aquifer systems. Coastal landward flow (seawater intrusion) occurs within both the upper- and lower-aquifer systems. A numerical ground-water flow model of the Santa Clara-Calleguas Basin was developed by the U.S. Geological Survey to better define the geohydrologic framework of the regional ground-water flow system and to help analyze the major problems affecting water-resources management of a typical coastal aquifer system. Construction of the Santa Clara-Calleguas Basin model required

  19. Impact of fire on global land surface air temperature and energy budget for the 20th century due to changes within ecosystems

    Science.gov (United States)

    Li, Fang; Lawrence, David M.; Bond-Lamberty, Ben

    2017-04-01

    Fire is a global phenomenon and tightly interacts with the biosphere and climate. This study provides the first quantitative assessment and understanding of fire’s influence on the global annual land surface air temperature and energy budget through its impact on terrestrial ecosystems. Fire impacts are quantified by comparing fire-on and fire-off simulations with the Community Earth System Model (CESM). Results show that, for the 20th century average, fire-induced changes in terrestrial ecosystems significantly increase global land annual mean surface air temperature by 0.18 °C, decrease surface net radiation and latent heat flux by 1.08 W m-2 and 0.99 W m-2, respectively, and have limited influence on sensible heat flux (-0.11 W m-2) and ground heat flux (+0.02 W m-2). Fire impacts are most clearly seen in the tropical savannas. Our analyses suggest that fire increases surface air temperature predominantly by reducing latent heat flux, mainly due to fire-induced damage to the vegetation canopy, and decreases net radiation primarily because fire-induced surface warming significantly increases upward surface longwave radiation. This study provides an integrated estimate of fire and induced changes in ecosystems, climate, and energy budget at a global scale, and emphasizes the importance of a consistent and integrated understanding of fire effects.

  20. Disposition of Lightning Activity Due to Pollution Load during Dissimilar Seasons as Observed from Satellite and Ground-Based Data

    Directory of Open Access Journals (Sweden)

    Anirban Middey

    2016-05-01

    Full Text Available The precise role of air pollution on the climate and local weather has been an issue for quite a long time. Among the diverse issues, the effects of air pollution on lightning are of recent interest. Exploration over several years (2004 to 2011 has been made over Gangetic West Bengal of India using lightning flash data from TRMM-LIS (Tropical Rainfall Measuring Mission-Lightning Imaging Sensor, atmospheric pollutants, and rainfall data during pre-monsoon (April and May and monsoon (June, July, August and September seasons. Near-surface pollutants such as PM10 and SO2 have a good positive association with aerosol optical depth (AOD for both the pre-monsoon and monsoon months. High atmospheric aerosol loading correlates well with pre-monsoon and monsoon lightning flashes. However, rainfall has a dissimilar effect on lightning flashes. Flash count is positively associated with pre-monsoon rainfall (r = 0.64, but the reverse relation (r = −0.4 is observed for monsoon rainfall. Apart from meteorological factors, wet deposition of atmospheric pollutant may be considered a crucial factor for decreased lightning flash count in monsoon. The variation in the monthly average tropospheric column amount of NO2, from the Tropospheric Emission Monitoring Internet Service (TEMIS, is synchronic with average lightning flash rate. It has a good linear association with flash count for both pre-monsoon and monsoon seasons. The effect of lightning on tropospheric NO2 production is evident from the monthly average variation in NO2 on lightning and non-lightning days.

  1. Urban archaeological investigations using surface 3D Ground Penetrating Radar and Electrical Resistivity Tomography methods

    Science.gov (United States)

    Papadopoulos, Nikos; Sarris, Apostolos; Yi, Myeong-Jong; Kim, Jung-Ho

    2009-02-01

    Ongoing and extensive urbanisation, which is frequently accompanied with careless construction works, may threaten important archaeological structures that are still buried in the urban areas. Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) methods are most promising alternatives for resolving buried archaeological structures in urban territories. In this work, three case studies are presented, each of which involves an integrated geophysical survey employing the surface three-dimensional (3D) ERT and GPR techniques, in order to archaeologically characterise the investigated areas. The test field sites are located at the historical centres of two of the most populated cities of the island of Crete, in Greece. The ERT and GPR data were collected along a dense network of parallel profiles. The subsurface resistivity structure was reconstructed by processing the apparent resistivity data with a 3D inversion algorithm. The GPR sections were processed with a systematic way, applying specific filters to the data in order to enhance their information content. Finally, horizontal depth slices representing the 3D variation of the physical properties were created. The GPR and ERT images significantly contributed in reconstructing the complex subsurface properties in these urban areas. Strong GPR reflections and high-resistivity anomalies were correlated with possible archaeological structures. Subsequent excavations in specific places at both sites verified the geophysical results. The specific case studies demonstrated the applicability of ERT and GPR techniques during the design and construction stages of urban infrastructure works, indicating areas of archaeological significance and guiding archaeological excavations before construction work.

  2. The impact of municipal landfill on surface and ground water quality in Bulawayo, Zimbabwe

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    R. Nyengera

    2012-11-01

    Full Text Available Leachate from Richmond municipal landfill, underlain by the Matsheumhlope unconfined aquifer in Bulawayo city and its consequent water resource quality impacts are evaluated. Leachate samples from collection ponds and water samples from a stream, and up and down-gradient boreholes fromthe landfill were tested for nine pollutants. The leachate pollutants found in both surface and ground water included metals (Fe, Pb and Hg and organic compounds that are hazardous to both human and the environmental health. Borehole water quality compliance with the relevant national and international regulations is reported. From borehole water samples, only chloride and nitrate with concentrations of 56.9 mg/ℓ and 2.26 mg/ℓ, respectively, were within the World Health Organisation (WHO recommended limits for drinking water of 250 mg/ℓ and 10 mg/ℓ, respectively. Lead and mercury concentrations of 0.22 mg/ℓ and 0.04 mg/ℓ were 10 times higher than WHO guidelines of 0.01 and 0.001 mg/ℓ, respectively. Both landfill and informal settlement activities near the landfill impact negatively to water resources quality in the area. City council should minimize waste by recycling, pre-treat collected leachate and drill monitoring wells around the landfill to check possible leachate leaks to water resources and take remedial actions, such assubmerged leachate combustion and evaporation.

  3. Characteristics of Ground Surface Temperatures as in situ Observed in Elevational Permafrost on the Northeastern Qinghai-Tibet Plateau

    Science.gov (United States)

    Luo, D.; Jin, H.; Marchenko, S. S.; Romanovsky, V. E.

    2016-12-01

    Elevational permafrost is primarily distributed on the Qinghai-Tibet Plateau (QTP) at mid-latitudes, where the average elevation is higher than 4,000 m a.s.l. The topography, including the elevation and aspect, obviously is the decisive controlling factor of thermal regimes of elevational permafrost, which is warm and extremely sensitive to anthropogenic activities and climate changes. Due to the harsh weather conditions and unfavorable logistics accommodations, however, the elevational permafrost on the QTP, especially in the rugged topography, is hard to be plotted through ground-based field investigations. The exact distribution of elevational permafrost could be simulated through GST. In this study, we set up three monitoring sites of GST at the beginning of 2015. One located in the rugged mountain of the source area of the Yellow River, one located in the sunny slope of the Bayan Har Mountain Pass, and one another located in a degrading alpine meadow of the source area of the Yangtze River. Based on these GST records, the daily, monthly, seasonal and year-average values of GST, freezing and thawing indices calculated from GST, and empirical Stefan Equation to calculate the ALT, as well as the GIPL-2.0 model to simulate the freezing and thawing processes of the active layer were integrative executed for these three sites. Results demonstrate that GST could be a much more reliable driving parameter to simulate the active layer and permafrost than the air temperature and land surface temperature.

  4. A study of the efficiency of spur gears made of powder metallurgy materials - ground versus super-finished surfaces

    OpenAIRE

    Li, Xinmin; Sosa, Mario; Andersson, Martin; Olofsson, Ulf

    2016-01-01

    Power loss is one of the main concerns in gear transmission systems. In this study a recirculating power back-to-back FZG test rig was used to investigate the efficiency of spur gears made of powder metallurgy (PM) material using two different surface manufacturing methods (ground and super-finished). The results were compared with previously presented results of standard gear material from the same test rig. The influence of the material (Wrought steel or PM) and surface roughness on the gea...

  5. Lithium content in potable water, surface water, ground water, and mineral water on the territory of Republic of Macedonia

    OpenAIRE

    Vesna Kostik; Biljana Bauer; Zoran Kavrakovski

    2014-01-01

    The aim of this study was to determine lithium concentration in potable water, surface water, ground, and mineral water on the territory of the Republic of Macedonia. Water samples were collected from water bodies such as multiple public water supply systems located in 13 cities, wells boreholes located in 12 areas, lakes and rivers located in three different areas. Determination of lithium concentration in potable water, surface water was performed by the technique of inductively coupl...

  6. Using distributed temperature sensing to monitor field scale dynamics of ground surface temperature and related substrate heat flux

    NARCIS (Netherlands)

    Bense, V.F.; Read, T.; Verhoef, A.

    2016-01-01

    We present one of the first studies of the use of distributed temperature sensing (DTS) along fibre-optic cables to purposely monitor spatial and temporal variations in ground surface temperature (GST) and soil temperature, and provide an estimate of the heat flux at the base of the canopy layer

  7. Effect of Surface Geology on Ground Motions: The Case of Station TAP056 - Chutzuhu Site

    Directory of Open Access Journals (Sweden)

    Kuo-Liang Wen

    2008-01-01

    Full Text Available In the Tatun mountain area of northern Taiwan are two strong motion stations approximately 2.5 km apart, TAP056 and TAP066 of the TSMIP network. The accelerometer at station TAP056 is often triggered by earthquakes, but that at TAP066 station is not. Comparisons of vertical and horizontal peak ground accelerations reveal PGA in the vertical, east-west, and north-south components at TAP056 station to be 3.89, 7.57, and 5.45 times those at station TAP066, respectively. The PGA ratio does not seem to be related to earthquake source or path. Fourier spectra of earthquake records at station TAP056 always have approximately the same dominant frequency; however, those at station TAP066 are different due to different sources and paths of different events. This shows that spectra at TAP056 station are mainly controlled by local site effects. The spectral ratios of TAP056/TAP066 show the S-wave is amplified at around 8 ~ 10 Hz. The horizontal/vertical spectral ratios of station TAP056 also show a dominant frequency at about 6 and 8 ~ 10 Hz. After dense microtremor surveying and the addition of one accelerometer just 20 meters away from the original observation station, we can confirm that the top soft soil layer upon which the observation station is constructed generates the local site response at station TAP056.

  8. Surface deformation due to slow slip source considering a non-elastic medium

    Science.gov (United States)

    Voss, N. K.; Malservisi, R.; Dixon, T. H.; Protti, M.

    2016-12-01

    Slow slip events (SSEs) are now recognized as a feature common in many subduction zones. They have been recognized in both the shallow part of subduction interface as well as deeper, beneath the seismogenic zone. While shallow events are difficult to image due to lack of resolution with onshore instrumentation, deep events appear to correlate well with seismic phenomena including tremor and low frequency events. However, uncertainty regarding source properties of the events and their surrounding medium remains high at these depths. Deep slow slip appears to be located between 60 and 25 km depth at many locations worldwide (Schwartz and Rokosky , 2007). This places the events at depths at or near the mantle wedge corner. Serpentinization of the mantle wedge is thought to be one source of fluids commonly attributed as the source of SSEs and tremor (Wada et al., 2008) but also leads to drastic changes in rheology of the down going slab and near by mantle. Traditionally, measured geodetic transients are inverted for slip distributions using a simple elastic "Okada" type models. Often the shape of these transients is attributed to variance in slip rate on the fault. Here we explore the response of the surrounding lithosphere to the transient stress propagation induced by SSE and the effects on observed surface deformation using varying rheologies within a finite element model. Understanding these effects allows a better estimation of the uncertainty in the geodetically derived slip distributions thus is important to consider when evaluating SSEs role in earthquake hazard as well as deciphering the relationship between tremor and slip.

  9. Evaluation of ground level concentration of pollutant due to gas flaring by computer simulation: A case study of Niger - Delta area of Nigeria

    Directory of Open Access Journals (Sweden)

    A. S. ABDULKAREEM

    2005-01-01

    Full Text Available The disposal of associated gases through flaring has been a major problem for the Nigerian oil and gas industries and most of theses gases are flared due to the lack of commercial out lets. The resultant effects of gas flaring are the damaging effect of the environment due to acid rain formation, green house effect, global warming and ozone depletion.This writes up is aimed at evaluating ground level concentration of CO2, SO2, NO2 and total hydrocarbon (THC, which are product of gas flared in oil producing areas. Volumes of gas flared at different flow station were collected as well as geometrical parameters. The results of simulation of model developed based on the principles of gaseous dispersion by Gaussian showed a good agreement with dispersion pattern.The results showed that the dispersion pattern of pollutants at ground level depends on the volume of gas flared, wind speed, velocity of discharge and nearness to the source of flaring. The results shows that continuous gas flaring irrespective of the quantity deposited in the immediate environment will in long run lead to change in the physicochemical properties of soil.

  10. Getting saturated hydraulic conductivity from surface Ground-Penetrating Radar measurements inside a ring infiltrometer

    Science.gov (United States)

    Leger, E.; Saintenoy, A.; Coquet, Y.

    2013-12-01

    Hydraulic properties of soils, described by the soil water retention and hydraulic conductivity functions, strongly influence water flow in the vadoze zone, as well as the partitioning of precipitation between infiltration into the soil and runoff along the ground surface. Their evaluation has important applications for modelling available water resources and for flood forecasting. It is also crucial to evaluate soil's capacity to retain chemical pollutants and to assess the potential of groundwater pollution. The determination of the parameters involved in soil water retention functions, 5 parameters when using the van Genuchten function, is usually done by laboratory experiments, such as the water hanging column. Hydraulic conductivity, on the other hand can be estimated either in laboratory, or in situ using infiltrometry tests. Among the large panel of existing tests, the single or double ring infiltrometers give the field saturated hydraulic conductivity by applying a positive charge on soils, whereas the disk infiltrometer allows to reconstruct the whole hydraulic conductivity curve, by applying different charges smaller than or equal to zero. In their classical use, volume of infiltrated water versus time are fitted to infer soil's hydraulic conductivity close to water saturation. Those tests are time-consuming and difficult to apply to landscape-scale forecasting of infiltration. Furthermore they involve many assumptions concerning the form of the infiltration bulb and its evolution. Ground-Penetrating Radar (GPR) is a geophysical method based on electromagnetic wave propagation. It is highly sensitive to water content variations directly related to the dielectric permittivity. In this study GPR was used to monitor water infiltration inside a ring infiltrometer and retrieve the saturated hydraulic conductivity. We carried out experiments in a quarry of Fontainebleau sand, using a Mala RAMAC system with antennae centered on 1600 MHz. We recorded traces at

  11. Implementing ground surface deformation tools to characterize field-scale properties of a fractured aquifer during a short hydraulic test

    Science.gov (United States)

    Schuite, Jonathan; Longuevergne, Laurent; Bour, Olivier; Boudin, Frédérick; Durand, Stéphane

    2016-04-01

    In naturally fractured reservoirs, fluid flow is governed by the structural and hydromechanical properties of fracture networks or conductive fault zones. In order to ensure a sustained exploitation of resources or to assess the safety of underground storage, it is necessary to evaluate these properties. As they generally form highly heterogeneous and anisotropic reservoirs, fractured media may be well characterized by means of several complementary experimental methods or sounding techniques. In this framework, the observation of ground deformation has been proved useful to gain insight of a fractured reservoir's geometry and hydraulic properties. Commonly, large conductive structures like faults can be studied from surface deformation from satellite methods at monthly time scales, whereas meter scale fractures have to be examined under short-term in situ experiments using high accuracy intruments like tiltmeters or extensometers installed in boreholes or at the ground's surface. To the best of our knowledge, the feasability of a field scale (~ 100 m) characterization of a fractured reservoir with geodetic tools in a short term experiment has not yet been addressed. In the present study, we implement two complementary ground surface geodetic tools, namely tiltmetry and optical leveling, to monitor the deformation induced by a hydraulic recovery test at the Ploemeur hydrological observatory (France). Employing a simple purely elastic modeling approach, we show that the joint use of time constraining data (tilt) and spatially constraining data (vertical displacement) makes it possible to evaluate the geometry (dip, root depth and lateral extent) and the storativity of a hydraulically active fault zone, in good agreement with previous studies. Hence we demonstrate that the adequate use of two complementary ground surface deformation methods offer a rich insight of large conductive structure's properties using a single short term hydraulic load. Ground surface

  12. On the wettability diversity of C/SiC surface: Comparison of the ground C/SiC surface and ablated C/SiC surface from three aspects

    Science.gov (United States)

    Wu, M. L.; Ren, C. Z.; Xu, H. Z.

    2016-11-01

    The coefficient of thermal conductivity was influenced by the wetting state of material. The wetting state usually depends on the surface wettability. C/SiC is a promising ceramic composites with multi-components. The wettability of C/SiC composites is hard to resort to the classical wetting theory directly. So far, few investigations focused on C/SiC surface wettability diversity after different material removal processes. In this investigation, comparative studies of surface wettability of ground C/SiC surface and laser-ablated C/SiC surface were carried out through apparent contact angle (APCA) measurements. The results showed that water droplets easily reached stable state on ground C/SiC surface; while the water droplets rappidly penetrated into the laser-ablated C/SiC surface. In order to find out the reason for wettability distinctions between the ground C/SiC surface and the laser-ablated C/SiC surface, comparative studies on the surface micro-structure, surface C-O-Si distribution, and surface C-O-Si weight percentage were carried out. The results showed that (1) A large number of micro cracks in the fuzzy pattern layer over laser-ablated C/SiC surfaces easily destoried the surface tension of water droplets, while only a few cracks existed over the ground C/SiC surfaces. (2) Chemical components (C, O, Si) were non-uniformly distributed on ground C/SiC surfaces, while the chemical components (C, O, Si) were uniformly distributed on laser-ablated C/SiC surfaces. (3) The carbon weight percentage on ground C/SiC surfaces were higher than that on laser-ablated C/SiC surfaces. All these made an essential contribution to the surface wettability diversity of C/SiC surface. Although more investigations about the quantitative influence of surface topography and surface chemical composition on composites wettability are still needed, the conslusion can be used in application: the wettability of C/SiC surface can be controlled by different material removal process

  13. Impact of the variability of the seasonal snow cover on the ground surface regimes in Hurd Peninsula (Livingston Island, Antarctic)

    Science.gov (United States)

    Nieuwendam, Alexandre; Ramos, Miguel; Vieira, Gonçalo

    2014-05-01

    Seasonally snow cover has a great impact on the thermal regime of the active layer and permafrost. Ground temperatures over a year are strongly affected by the timing, duration, thickness, structure and physical and thermal properties of snow cover. The purpose of this communication is to characterize the shallow ground thermal regimes, with special reference to the understanding of the influence snow cover in permafrost spatial distribution, in the ice-free areas of the north western part of Hurd Peninsula in the vicinity of the Spanish Antarctic Station "Juan Carlos I" and Bulgarian Antarctic Station "St. Kliment Ohridski". We have analyzed and ground temperatures as well as snow thickness data in four sites distributed along an altitudinal transect in Hurd Peninsula from 2007 to 2013: Nuevo Incinerador (25 m asl), Collado Ramos (110 m), Ohridski (140 m) and Reina Sofia Peak (275 m). At each study site, data loggers were installed for the monitoring of air temperatures (at 1.5 m high), ground temperatures (5, 20 and 40 cm depth) and for snow depth (2, 5, 10, 20, 40, 80 and 160 cm) at 4-hour intervals. The winter data suggests the existence of three types of seasonal stages regarding the ground surface thermal regime and the thickness of snow cover: (a) shallow snow cover with intense ground temperatures oscillations; (b) thick snow cover and low variations of soil temperatures; and (c) stability of ground temperatures. Ground thermal conditions are also conditioned by a strong variability. Winter data indicates that Nuevo Incinerador site experiences more often thicker snow cover with higher ground temperatures and absence of ground temperatures oscillations. Collado Ramos and Ohridski show frequent variations of snow cover thickness, alternating between shallow snow cover with high ground temperature fluctuation and thick snow cover and low ground temperature fluctuation. Reina Sofia in all the years has thick snow cover with little variations in soil

  14. Use of a size-resolved 1-D resuspension scheme to evaluate resuspended radioactive material associated with mineral dust particles from the ground surface.

    Science.gov (United States)

    Ishizuka, Masahide; Mikami, Masao; Tanaka, Taichu Y; Igarashi, Yasuhito; Kita, Kazuyuki; Yamada, Yutaka; Yoshida, Naohiro; Toyoda, Sakae; Satou, Yukihiko; Kinase, Takeshi; Ninomiya, Kazuhiko; Shinohara, Atsushi

    2017-01-01

    A size-resolved, one-dimensional resuspension scheme for soil particles from the ground surface is proposed to evaluate the concentration of radioactivity in the atmosphere due to the secondary emission of radioactive material. The particle size distributions of radioactive particles at a sampling point were measured and compared with the results evaluated by the scheme using four different soil textures: sand, loamy sand, sandy loam, and silty loam. For sandy loam and silty loam, the results were in good agreement with the size-resolved atmospheric radioactivity concentrations observed at a school ground in Tsushima District, Namie Town, Fukushima, which was heavily contaminated after the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. Though various assumptions were incorporated into both the scheme and evaluation conditions, this study shows that the proposed scheme can be applied to evaluate secondary emissions caused by aeolian resuspension of radioactive materials associated with mineral dust particles from the ground surface. The results underscore the importance of taking soil texture into account when evaluating the concentrations of resuspended, size-resolved atmospheric radioactivity.

  15. Features of electromagnetic waves in a complex plasma due to surface plasmon resonances on macroparticles

    CERN Document Server

    Vladimirov, S V

    2015-01-01

    The dielectric properties of complex plasma containing either metal or dielectric spherical inclusions (macroparticles, dust) are investigated. We focus on surface plasmon resonances on the macroparticle surfaces and their effect on electromagnetic wave propagation. It is demonstrated that the presence of surface plasmon oscillations significantly modifies plasma electromagnetic properties by resonances and cutoffs in the effective permittivity. This leads to related branches of electromagnetic waves and to the wave band gaps. The results are discussed in the context of dusty plasma experiments.

  16. [Heavy metals in the surface sediment of the dumping ground outside Jiaozhou Bay and their potential ecological risk].

    Science.gov (United States)

    Cao, Cong-hua; Zhang, Nai-xing; Wu, Feng-cong; Sun, Bin; Ren, Rong-zhu; Sun, Xu; Lin, Sen; Zhang, Shao-ping

    2011-05-01

    Based on the monitoring data of heavy metals (Cr, Hg, Cd, Pb, Zn, Cu) in the surface sediment of the dumping ground outside Jiaozhou Bay from 2003 to 2008, the distribution patterns, factors controlling the distribution, and the potential ecological risks of heavy metals were studied with the data in 2007-08, and the fluctuation trends of heavy metals in the surface sediment over the 6 years were also discussed. The average concentrations of heavy metals Cr, Hg, Cd, Pb, Zn, Cu in the surface sediment were 29.47, 0.065, 0.105, 1.145, 9.63, 3.355 microg/g, respectively. Except for Cr, the concentration of heavy metals was high in the central dumping area while low outside the dumping ground, suggesting that the dredged material dumped was the main source of heavy metals. Organic carbon content in the surface sediment had a significant positive correlation with heavy metals except for Cr. Based on the results of ecological risk assessment, Hg had a medium potential ecological risk, while the other heavy metals had low potential ecological risk. The overall risk index (RI) of the heavy metals was 100.50, which was considered as a level of low potential ecological risk. The average concentration of heavy metals showed a decreasing trend over the 6 years, except Hg. In conclusion, the quality of surface sediment in term of heavy metals in the dumping ground outside Jiaozhou Bay is relatively good.

  17. Application of terrestrial laser scanning for detection of ground surface deformation in small mud volcano (Murono, Japan)

    Science.gov (United States)

    Hayakawa, Yuichi S.; Kusumoto, Shigekazu; Matta, Nobuhisa

    2016-07-01

    We perform terrestrial laser scanning (TLS) to detect changes in surface morphology of a mud volcano in Murono, north-central Japan. The study site underwent significant deformation by a strong earthquake in 2011, and the surface deformation has continued in the following years. The point cloud datasets were obtained by TLS at three different times in 2011, 2013 and 2014. Those point clouds were aligned by cloud-based registration, which minimizes the closest point distance of point clouds of unchanged ground features, and the TLS-based point cloud data appear to be suitable for detecting centimeter-order deformations in the central domain of the mud volcano, as well as for measurements of topographic features including cracks of paved ground surface. The spatial patterns and accumulative amount of the vertical deformation during 2011-2014 captured by TLS correspond well with those previously reported based on point-based leveling surveys, supporting the validity of TLS survey.

  18. Hydrogel Inverse Replicas of Breath Figures Exhibit Superoleophobicity Due to Patterned Surface Roughness.

    Science.gov (United States)

    Arora, Jaspreet Singh; Cremaldi, Joseph C; Holleran, Mary Kathleen; Ponnusamy, Thiruselvam; He, Jibao; Pesika, Noshir S; John, Vijay T

    2016-02-02

    The wetting behavior of a surface depends on both its surface chemistry and the characteristics of surface morphology and topography. Adding structure to a flat hydrophobic or oleophobic surface increases the effective contact angle and thus the hydrophobicity or oleophobicity of the surface, as exemplified by the lotus leaf analogy. We describe a simple strategy to introduce micropatterned roughness on surfaces of soft materials, utilizing the template of hexagonally packed pores of breath figures as molds. The generated inverse replicas represent micron scale patterned beadlike protrusions on hydrogel surfaces. This added roughness imparts superoleophobic properties (contact angle of the order of 150° and greater) to an inherently oleophobic flat hydrogel surface, when submerged. The introduced pattern on the hydrogel surface changes morphology as it swells in water to resemble morphologies remarkably analogous to the compound eye. Analysis of the wetting behavior using the Cassie-Baxter approximation leads to estimation of the contact angle in the superoleophobic regime and in agreement with the experimental value.

  19. Calculation of Electric Field at Ground Surface and ADSS Cable Prepared Hanging Point near EHV Power Transmission Tower

    Directory of Open Access Journals (Sweden)

    Xu Bao-Qing

    2016-01-01

    Full Text Available A simplified model of the 750kV tower is established by CDEGS software which is based on the Method Of Moment. The power frequency electric field distribution on the ground is achieved by software calculation and field-measuring. The validity of the calculation is proved when compare the calculation and experiment results. The model also can be used to calculate the electric field in prepared hanging points on the tower. Results show that the electric field distribution on the ground surface around the tower and prepared hanging points are meet the standard by calculation and experiment.

  20. Analysis of the Effects of Vitiates on Surface Heat Flux in Ground Tests of Hypersonic Vehicles

    Science.gov (United States)

    Cuda, Vincent; Gaffney, Richard L

    2008-01-01

    To achieve the high enthalpy conditions associated with hypersonic flight, many ground test facilities burn fuel in the air upstream of the test chamber. Unfortunately, the products of combustion contaminate the test gas and alter gas properties and the heat fluxes associated with aerodynamic heating. The difference in the heating rates between clean air and a vitiated test medium needs to be understood so that the thermal management system for hypersonic vehicles can be properly designed. This is particularly important for advanced hypersonic vehicle concepts powered by air-breathing propulsion systems that couple cooling requirements, fuel flow rates, and combustor performance by flowing fuel through sub-surface cooling passages to cool engine components and preheat the fuel prior to combustion. An analytical investigation was performed comparing clean air to a gas vitiated with methane/oxygen combustion products to determine if variations in gas properties contributed to changes in predicted heat flux. This investigation started with simple relationships, evolved into writing an engineering-level code, and ended with running a series of CFD cases. It was noted that it is not possible to simultaneously match all of the gas properties between clean and vitiated test gases. A study was then conducted selecting various combinations of freestream properties for a vitiated test gas that matched clean air values to determine which combination of parameters affected the computed heat transfer the least. The best combination of properties to match was the free-stream total sensible enthalpy, dynamic pressure, and either the velocity or Mach number. This combination yielded only a 2% difference in heating. Other combinations showed departures of up to 10% in the heat flux estimate.

  1. Time-dependent inversion of surface subsidence due to dynamic reservoir compaction

    NARCIS (Netherlands)

    Muntendam-Bos, A.G.; Kroon, I.C.; Fokker, P.A.

    2008-01-01

    We introduce a novel, time-dependent inversion scheme for resolving temporal reservoir pressure drop from surface subsidence observations (from leveling or GPS data, InSAR, tiltmeter monitoring) in a single procedure. The theory is able to accommodate both the absence of surface subsidence estimates

  2. Enhanced charge recombination due to surfaces and twin defects in GaAs nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Evan; Sheng, Chunyang; Nakano, Aiichiro [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Shimamura, Kohei; Shimojo, Fuyuki [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Department of Physics, Kumamoto University, Kumamoto 860-8555 (Japan)

    2015-02-07

    Power conversion efficiency of gallium arsenide (GaAs) nanowire (NW) solar cells is severely limited by enhanced charge recombination (CR) at sidewall surfaces, but its atomistic mechanisms are not well understood. In addition, GaAs NWs usually contain a high density of twin defects that form a twin superlattice, but its effects on CR dynamics are largely unknown. Here, quantum molecular dynamics (QMD) simulations reveal the existence of an intrinsic type-II heterostructure at the (110) GaAs surface. Nonadiabatic quantum molecular dynamics (NAQMD) simulations show that the resulting staggered band alignment causes a photoexcited electron in the bulk to rapidly transfer to the surface. We have found orders-of-magnitude enhancement of the CR rate at the surface compared with the bulk value. Furthermore, QMD and NAQMD simulations show unique surface electronic states at alternating (111)A and (111)B sidewall surfaces of a twinned [111]-oriented GaAs NW, which act as effective CR centers. The calculated large surface recombination velocity quantitatively explains recent experimental observations and provides microscopic understanding of the underlying CR processes.

  3. Using Self-Similarity to Simulate Meniscus Evolution Around TMV Due to Surface Diffusion

    Science.gov (United States)

    Potter, Richard; Zhang, Yue; Fakhraai, Zahra

    It has been hypothesized that enhanced surface diffusion allows the formation of stable molecular glasses during physical vapor deposition. The improved properties of these glasses, such as increased density and kinetic stability can help improve material properties in pioneering fields of technology such as organic electronics and pharmaceutical drug delivery. While surface diffusion has been measured previously on the surfaces of organic glasses, direct measurements on the surface of vapor-deposited stable glasses has proven more challenging. This research focuses on a straightforward method for measuring the surface diffusion coefficients of molecular glasses through the use of tobacco mosaic virus (TMV) nanorods as probe particles. In conjunction, mathematical models based on the thin film equation were used to simulate fast meniscus formation around the nanorods on the glassy surface. The evolution of the meniscus is self-similar, which allows quick quantification of the diffusion coefficient, by solving the time evolution for a single experiment. Experimental data were compared and fit to these simulations to derive a quantity for the surface diffusion coefficient, Ds. Nsf-CAREER DMR-1350044.

  4. Investigating the Impacts of Surface Temperature Anomalies due to Burned Area Albedo in Northern sub-Saharan Africa

    Science.gov (United States)

    Gabbert, T.; Matsui, T.; Capehart, W. J.; Ichoku, C. M.; Gatebe, C. K.

    2015-12-01

    The northern Sub-Saharan African region (NSSA) is an area of intense focus due to periodic severe droughts that have dire consequences on the growing population, which relies mostly on rain fed agriculture for its food supply. This region's weather and hydrologic cycle are very complex and are dependent on the West African Monsoon. Different regional processes affect the West African Monsoon cycle and variability. One of the areas of current investigation is the water cycle response to the variability of land surface characteristics. Land surface characteristics are often altered in NSSA due to agricultural practices, grazing, and the fires that occur during the dry season. To better understand the effects of biomass burning on the hydrologic cycle of the sub-Saharan environment, an interdisciplinary team sponsored by NASA is analyzing potential feedback mechanisms due to the fires. As part of this research, this study focuses on the effects of land surface changes, particularly albedo and skin temperature, that are influenced by biomass burning. Surface temperature anomalies can influence the initiation of convective rainfall and surface albedo is linked to the absorption of solar radiation. To capture the effects of fire perturbations on the land surface, NASA's Unified Weather and Research Forecasting (NU-WRF) model coupled with NASA's Land Information System (LIS) is being used to simulate burned area surface albedo inducing surface temperature anomalies and other potential effects to environmental processes. Preliminary sensitivity results suggest an altered surface radiation budget, regional warming of the surface temperature, slight increase in average rainfall, and a change in precipitation locations.

  5. Experimental studies of the streaming flow due to the adsorption of particles at a liquid surface

    Science.gov (United States)

    Singh, Pushpendra; Musunuri, Naga; Fischer, Ian

    2016-11-01

    The particle image velocimetry (PIV) technique is used to study the streaming flow that is induced when particles are adsorbed at a liquid surface. The flow develops within a fraction of second after the adsorption of the particle and persists for several seconds. The fluid directly below the particle rises upward, and near the surface, it moves away from the particle. The flow causes powders sprinkled on a liquid surface to disperse on the surface. The flow strength, and the volume over which it extends, decreases with decreasing particle size. The streaming flow induced by the adsorption of two or more particles is a combination of the flows which they induce individually. The work was supported by National Science Foundation.

  6. Numerical study on cavitating flow due to a hydrofoil near a free surface

    Directory of Open Access Journals (Sweden)

    Ping-Chen Wu

    2016-09-01

    Full Text Available A numerical strategy is proposed for a viscous uniform flow past a 2-D partially cavitating hydrofoil placed at a finite depth from the free surface. The flow was modeled by the Reynolds-averaged Navier–Stokes (RANS equations. A finite-volume method with the SIMPLE scheme and k-ε turbulence model were employed for computations. The “full cavitation model,” which included the effects of vaporization, noncondensible gases and compressibility, was incorporated in the computation of cavitating flow. The cavity shape and free surface were updated iteratively till a reasonable convergence was reached. As for the determination of the free surface, the VOF approach was adopted. The test cases show the accuracy and stability of our procedure to capture the cavitating flow near the free surface.

  7. Ground water/surface water responses to global climate simulations, Santa Clara-Calleguas Basin, Ventura, California

    Science.gov (United States)

    Hanson, R.T.; Dettinger, M.D.

    2005-01-01

    Climate variations can play an important, if not always crucial, role in successful conjunctive management of ground water and surface water resources. This will require accurate accounting of the links between variations in climate, recharge, and withdrawal from the resource systems, accurate projection or predictions of the climate variations, and accurate simulation of the responses of the resource systems. To assess linkages and predictability of climate influences on conjunctive management, global climate model (GCM) simulated precipitation rates were used to estimate inflows and outflows from a regional ground water model (RGWM) of the coastal aquifers of the Santa ClaraCalleguas Basin at Ventura, California, for 1950 to 1993. Interannual to interdecadal time scales of the El Nin??o Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) climate variations are imparted to simulated precipitation variations in the Southern California area and are realistically imparted to the simulated ground water level variations through the climate-driven recharge (and discharge) variations. For example, the simulated average ground water level response at a key observation well in the basin to ENSO variations of tropical Pacific sea surface temperatures is 1.2 m/??C, compared to 0.9 m/??C in observations. This close agreement shows that the GCM-RGWM combination can translate global scale climate variations into realistic local ground water responses. Probability distributions of simulated ground water level excursions above a local water level threshold for potential seawater intrusion compare well to the corresponding distributions from observations and historical RGWM simulations, demonstrating the combination's potential usefulness for water management and planning. Thus the GCM-RGWM combination could be used for planning purposes and - when the GCM forecast skills are adequate - for near term predictions.

  8. Oxidation of the Martian surface - Constraints due to chemical processes in the atmosphere

    Science.gov (United States)

    Mcelroy, M. B.; Kong, T. Y.

    1976-01-01

    Dissociation of water in the Martian atmosphere may supply oxygen to the surface and may result in the formation of minerals such as goethite, as proposed by Huguenin. The supply rate is limited by chemical processes in the atmosphere which regulate the abundance of O2. The net surface sink for atmospheric oxygen can be as large as 33 million atoms per sq cm per sec which compares to the escape rate of 60 million atoms per sq cm per sec.

  9. Nutrients in ground water and surface water of the United States; an analysis of data through 1992

    Science.gov (United States)

    Mueller, D.K.; Hamilton, P.A.; Helsel, D.R.; Hitt, K.J.; Ruddy, B.C.

    1995-01-01

    Historical data on nutrient (nitrogen and phosphorus species) concentrations in ground-and surface-water samples were compiled from 20 study units of the National Water-Quality Assessment (NAWQA) Program and 5 supplemental study areas. The resultant national retrospective data sets contained analyses of about 12,000 Found-water and more than 22,000 surface-water samples. These data were interpreted on regional and national scales by relating the distributions of nutrient concentrations to ancillary data, such as land use, soil characteristics, and hydrogeology, provided by local study-unit personnel. The information provided in this report on environmental factors that affect nutrient concentrations in ground and surface water can be used to identify areas of the Nation where the vulnerability to nutrient contamination is greatest. Nitrate was the nutrient of greatest concern in the historical ground-water data. It is the only nutrient that is regulated by a national drinking-water standard. Nitrate concentrations were significantly different in ground water affected by various land uses. Concentrations in about 16 percent of the samples collected in agricultural areas exceeded the drinking-water standard. However, the standard was exceeded in only about 1 percent of samples collected from public-supply wells. A variety of ancillary factors had significant relations to nitrate concentrations in ground water beneath agricultural areas. Concentrations generally were highest within 100 feet of the land surface. They were also higher in areas where soil and geologic characteristics promoted rapid movement of water to the aquifer. Elevated concentrations commonly occurred in areas underlain by permeable materials, such as carbonate bedrock or unconsolidated sand and gravel, and where soils are generally well drained. In areas where water movement is impeded, denitrification might lead to low concentrations of nitrate in the ground water. Low concentrations were also

  10. Colored grounds of gilt stucco surfaces as analyzed by a combined microscopic, spectroscopic and elemental analytical approach.

    Science.gov (United States)

    Sansonetti, A; Striova, J; Biondelli, D; Castellucci, E M

    2010-08-01

    A survey of gilts applied to stucco surfaces that specifically focuses on the compositions of their colored grounds is reported. Gilt samples of a common geographical (Lombardy in Italy) and temporal provenance (17th-18th century) were studied in the form of polished cross-sections by optical and electron microscopy (SEM-EDS), micro-Raman (microRaman) spectroscopy and Fourier-transform infrared microspectroscopy (microFTIR). Comparing samples with superimposed grounds and gilts enabled light to be shed on the choice of specific materials, their stratigraphic functions, decorative effects, and technological performances. Iron oxide pigments were found in the older grounds, sometimes in the presence of lead white (2PbCO(3).Pb(OH)(2)) or minium (Pb(3)O(4)). In more recent grounds, chrome yellow (PbCrO(4)), chrome orange (PbCrO(4).PbO), cinnabar (alpha-HgS) and barium white (BaSO(4)), invariably mixed with lead white, were encountered. Evidence for the use of organic mordants (colophony and wax, or siccative oil) was obtained by microFTIR. This combined microFTIR and microRaman spectroscopic and elemental (SEM-EDS) analytical approach enhances knowledge of the composition of gold grounds, their variability and their chronological evolution.

  11. Study on the applicability of frequency spectrum of micro-tremor and dynamic characteristics of surface ground in Asia area

    Institute of Scientific and Technical Information of China (English)

    CHE Ai-lan; IWATATE Takahiro; ODA Yoshiya; GE Xiu-run

    2006-01-01

    The dynamic characteristics of ground soil using micro-tremor observation in Asia (Zushi and Ogasawara (Japan),Xi'an (China), Manila (Philippines), and Gujarat (India)) are studied. Ground micro-tremor signals were observed and analyzed by fast Fourier transform method (FFT). The response of ground soil to frequency of ground micro-tremor is revealed, and functions with frequency-dependence and frequency-selection of micro-tremor for different foundation soil strata are also researched.The horizontal to vertical spectral ratio (H/V, Nakamura technique) of micro-tremor observed at the surface ground was used to evaluate the site's predominant period. This paper also discusses the application of micro-tremor on site safety evaluation, and gives the observed calculation results obtained at multiple points. The experimental foundation and the deduction process of the method are described in detail. Some problems of the method are pointed out. Potential use of the technique's good expandable nature makes it a useable means for preventing and reducing disaster's harmful effects.

  12. Amplification of Surface-Enhanced Raman Scattering Due to Substrate-Mediated Localized Surface Plasmons in Gold Nanodimers

    KAUST Repository

    Yue, Weisheng

    2017-03-28

    Surface-enhanced Raman scattering (SERS) is ubiquitous in chemical and biochemical sensing, imaging and identification. Maximizing SERS enhancement is a continuous effort focused on the design of appropriate SERS substrates. Here we show that significant improvement in a SERS signal can be achieved with substrates combining localized surface plasmon resonances and a nonresonant plasmonic substrate. By introducing a continuous gold (Au) film underneath Au nanodimers antenna arrays, an over 10-fold increase in SERS enhancement is demonstrated. Triangular, rectangle and disc dimers were studied, with bowtie antenna providing highest SERS enhancement. Simulations of electromagnetic field distributions of the Au nanodimers on the Au film support the observed enhancement dependences. The hybridization of localized plasmonic modes with the image modes in a metal film provides a straightforward way to improve SERS enhancement in designer SERS substrate.

  13. Algae metabolism and organic carbon in sediments determining arsenic mobilisation in ground- and surface water. A field study in Doñana National Park, Spain.

    Science.gov (United States)

    Kohfahl, Claus; Navarro, Daniel Sánchez-Rodas; Mendoza, Jorge Armando; Vadillo, Iñaki; Giménez-Forcada, Elena

    2016-02-15

    A study has been performed to explore the origin, spatiotemporal behaviour and mobilisation mechanism of the elevated arsenic (As) concentrations found in ground water and drinking ponds of the Doñana National Park, Southern Spain. At a larger scale, 13 piezometers and surface water samples of about 50 artificial drinking ponds and freshwater lagoons throughout the National Park were collected and analysed for major ions, metals and trace elements. At a smaller scale, 5 locations were equipped with piezometers and groundwater was sampled up to 4 times for ambient parameters, major ions, metals, trace elements and iron (Fe) speciation. As was analysed for inorganic and organic speciation. Undisturbed sediment samples were analysed for physical parameters, mineralogy, geochemistry as well as As species. Sediment analyses yielded total As between 0.1 and 18 mg/kg and are not correlated with As concentration in water. Results of the surface- and groundwater sampling revealed elevated concentration of As up to 302 μg/L within a restricted area of the National Park. Results of groundwater sampling reveals strong correlation of As with Fe(2+) pointing to As mobilisation due to reductive dissolution of hydroferric oxides (HFO) in areas of locally elevated amounts of organic matter within the sediments. High As concentrations in surface water ponds are correlated with elevated alkalinity and pH attributed to algae metabolism, leading to As desorption from HFO. The algae metabolism is responsible for the presence of methylated arsenic species in surface water, in contrast to ground water in which only inorganic As species was found. Temporal variations in surface water and groundwater are also related to changes in pH and alkalinity as a result of enhanced algae metabolism in surface water or related to changes in the redox level in the case of groundwater.

  14. The study of single station inverting the sea surface current by HF ground wave radar based on adjoint assimilation technology

    Science.gov (United States)

    Han, Shuzong; Yang, Hua; Xue, Wenhu; Wang, Xingchi

    2017-06-01

    This paper introduces the assimilation technology in an ocean dynamics model and discusses the feasibility of inverting the sea surface current in the detection zone by assimilating the sea current radial velocity detected by single station HF ground wave radar in ocean dynamics model. Based on the adjoint assimilation and POM model, the paper successfully inverts the sea surface current through single station HF ground wave radar in the Zhoushan sea area. The single station HF radar inversion results are also compared with the bistatic HF radar composite results and the fixed point measured results by Annderaa current meter. The error analysis shows that acquisition of flow velocity and flow direction data from the single station HF radar based on adjoint assimilation and POM model is viable and the data obtained have a high correlation and consistency with the flow field observed by HF radar.

  15. SURFACE WATER AND GROUND WATER QUALITY MONITORING FOR RESTORATION OF URBAN LAKES IN GREATER HYDERABAD, INDIA

    Science.gov (United States)

    Mohanty, A. K.

    2009-12-01

    SURFACE WATER AND GROUND WATER QUALITY MONITORING FOR RESTORATION OF URBAN LAKES IN GREATER HYDERABAD, INDIA A.K. Mohanty, K. Mahesh Kumar, B. A. Prakash and V.V.S. Gurunadha Rao Ecology and Environment Group National Geophysical Research Institute, (CSIR) Hyderabad - 500 606, India E-mail:atulyakumarmohanty@yahoo.com Abstract: Hyderabad Metropolitan Development Authority has taken up restoration of urban lakes around Hyderabad city under Green Hyderabad Environment Program. Restoration of Mir Alam Tank, Durgamcheruvu, Patel cheruvu, Pedda Cheruvu and Nallacheruvu lakes have been taken up under the second phase. There are of six lakes viz., RKPuramcheruvu, Nadimicheruvu (Safilguda), Bandacheruvu Patelcheruvu, Peddacheruvu, Nallacheruvu, in North East Musi Basin covering 38 sq km. Bimonthly monitoring of lake water quality for BOD, COD, Total Nitrogen, Total phosphorous has been carried out for two hydrological cycles during October 2002- October 2004 in all the five lakes at inlet channels and outlets. The sediments in the lake have been also assessed for nutrient status. The nutrient parameters have been used to assess eutrophic condition through computation of Trophic Status Index, which has indicated that all the above lakes under study are under hyper-eutrophic condition. The hydrogeological, geophysical, water quality and groundwater data base collected in two watersheds covering 4 lakes has been used to construct groundwater flow and mass transport models. The interaction of lake-water with groundwater has been computed for assessing the lake water budget combining with inflow and outflow measurements on streams entering and leaving the lakes. Individual lake water budget has been used for design of appropriate capacity of Sewage Treatment Plants (STPs) on the inlet channels of the lakes for maintaining Full Tank Level (FTL) in each lake. STPs are designed for tertiary treatment i.e. removal of nutrient load viz., Phosphates and Nitrates. Phosphates are

  16. Computational simulation of surface waviness in graphite/epoxy woven composites due to initial curing

    Science.gov (United States)

    Sanfeliz, Jose G.; Murthy, Pappu L. N.; Chamis, Christos C.

    1992-01-01

    Several models simulating plain weave, graphite/epoxy woven composites are presented, along with the effects that the simultaneous application of pressure and thermal loads have on their surfaces. The surface effects created by moisture absorption are also examined. The computational simulation consisted of using a two-dimensional finite element model for the composite. The properties of the finite element (FE) model are calculated by using the in-house composite mechanics computer code ICAN (Integrated Composite ANalyzer). MSC/NASTRAN is used for the FE analysis which yields the composite's top surface normalized displacements. These results demonstrate the importance of parameters such as the cure temperature (T sub o) and the resin content in the curing process of polymer-matrix composites. The modification of these parameters will help tailor the composite system to the desired requirements and applications.

  17. Frequency shifts of resonant modes of the Sun due to near-surface convective scattering

    CERN Document Server

    Bhattacharya, Jishnu; Antia, H M

    2015-01-01

    Measurements of oscillation frequencies of the Sun and stars can provide important independent constraints on their internal structure and dynamics. Seismic models of these oscillations are used to connect structure and rotation of the star to its resonant frequencies, which are then compared with observations, the goal being that of minimizing the difference between the two. Even in the case of the Sun, for which structure models are highly tuned, observed frequencies show systematic deviations from modeled frequencies, a phenomenon referred to as the "surface term." The dominant source of this systematic effect is thought to be vigorous near-surface convection, which is not well accounted for in both stellar modeling and mode-oscillation physics. Here we bring to bear the method of homogenization, applicable in the asymptotic limit of large wavelengths (in comparison to the correlation scale of convection), to characterize the effect of small-scale surface convection on resonant-mode frequencies in the Sun....

  18. Nanocrystals in compression: unexpected structural phase transition and amorphization due to surface impurities

    Science.gov (United States)

    Liu, Gang; Kong, Lingping; Yan, Jinyuan; Liu, Zhenxian; Zhang, Hengzhong; Lei, Pei; Xu, Tao; Mao, Ho-Kwang; Chen, Bin

    2016-06-01

    We report an unprecedented surface doping-driven anomaly in the compression behaviors of nanocrystals demonstrating that the change of surface chemistry can lead to an interior bulk structure change in nanoparticles. In the synchrotron-based X-ray diffraction experiments, titania nanocrystals with low concentration yttrium dopants at the surface are found to be less compressible than undoped titania nanocrystals. More surprisingly, an unexpected TiO2(ii) phase (α-PbO2 type) is induced and obvious anisotropy is observed in the compression of yttrium-doped TiO2, in sharp contrast to the compression behavior of undoped TiO2. In addition, the undoped brookite nanocrystals remain with the same structure up to 30 GPa, whereas the yttrium-doped brookite amorphizes above 20 GPa. The abnormal structural evolution observed in yttrium-doped TiO2 does not agree with the reported phase stability of nano titania polymorphs, thus suggesting that the physical properties of the interior of nanocrystals can be controlled by the surface, providing an unconventional and new degree of freedom in search for nanocrystals with novel tunable properties that can trigger applications in multiple areas of industry and provoke more related basic science research.We report an unprecedented surface doping-driven anomaly in the compression behaviors of nanocrystals demonstrating that the change of surface chemistry can lead to an interior bulk structure change in nanoparticles. In the synchrotron-based X-ray diffraction experiments, titania nanocrystals with low concentration yttrium dopants at the surface are found to be less compressible than undoped titania nanocrystals. More surprisingly, an unexpected TiO2(ii) phase (α-PbO2 type) is induced and obvious anisotropy is observed in the compression of yttrium-doped TiO2, in sharp contrast to the compression behavior of undoped TiO2. In addition, the undoped brookite nanocrystals remain with the same structure up to 30 GPa, whereas the yttrium

  19. Simulated potentiometric surface contours at end of simulation (1998) in model layer 1 of the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These contours represent the simulated potentiometric surface at the end of simulation (1998) in model layer 1 of the Death Valley regional ground-water flow system...

  20. Simulated potentiometric surface contours of prepumping conditions in layer 1 of the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These simulated potentiometric surface contours represent prepumping (or steady-state) conditions for model layer 1 of the Death Valley regional ground-water flow...

  1. Simulated potentiometric surface contours of prepumping conditions in layer 16 of the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These simulated potentiometric surface contours represent prepumping (or steady-state) conditions for model layer 16 of the Death Valley regional ground-water flow...

  2. Simulated potentiometric surface contours at end of simulation (1998) in model layer 16 of the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These contours represent the simulated potentiometric surface at the end of simulation (1998) in model layer 16 of the Death Valley regional ground-water flow system...

  3. Simulated potentiometric surface contours at end of simulation (1998) in model layer 1 of the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These contours represent the simulated potentiometric surface at the end of simulation (1998) in model layer 1 of the Death Valley regional ground-water flow system...

  4. Simulated potentiometric surface contours at end of simulation (1998) in model layer 16 of the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These contours represent the simulated potentiometric surface at the end of simulation (1998) in model layer 16 of the Death Valley regional ground-water flow...

  5. Development of a Remotely Operated, Field-Deployable Tritium Analysis System for Surface and Ground Water Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Hofstetter, K.J. [Westinghouse Savannah River Company, AIKEN, SC (United States); Cable, P.R.; Noakes, J.E. [University of Georgia, , GA (United States); Spaulding, J.D. [University of Georgia, , GA (United States); Neary, M. P. [University of Georgia, , GA (United States); Wasyl, M.S. [Packard Instrument Company, , ()

    1996-06-20

    The environmental contamination resulting from decades of testing and manufacturing of nuclear materials for a national defense purposes is a problem now being faced by the United States. The Center for Applied Isotope Studies at the University of Georgia, in cooperation with the Westinghouse Savannah River Company and Packard Instrument Company, have developed a prototype unit for remote, near real time, in situ analysis of tritium in surface and ground water samples.

  6. Estrogen and androgen receptor activities of hydraulic fracturing chemicals and surface and ground water in a drilling-dense region

    Science.gov (United States)

    Kassotis, Christopher D.; Tillitt, Donald E.; Davis, J. Wade; Hormann, Anette M.; Nagel, Susan C.

    2014-01-01

    The rapid rise in natural gas extraction using hydraulic fracturing increases the potential for contamination of surface and ground water from chemicals used throughout the process. Hundreds of products containing more than 750 chemicals and components are potentially used throughout the extraction process, including more than 100 known or suspected endocrine-disrupting chemicals. We hypothesized thataselected subset of chemicalsusedin natural gas drilling operationsandalso surface and ground water samples collected in a drilling-dense region of Garfield County, Colorado, would exhibit estrogen and androgen receptor activities. Water samples were collected, solid-phase extracted, and measured for estrogen and androgen receptor activities using reporter gene assays in human cell lines. Of the 39 unique water samples, 89%, 41%, 12%, and 46% exhibited estrogenic, antiestrogenic, androgenic, and antiandrogenic activities, respectively. Testing of a subset of natural gas drilling chemicals revealed novel antiestrogenic, novel antiandrogenic, and limited estrogenic activities. The Colorado River, the drainage basin for this region, exhibited moderate levels of estrogenic, antiestrogenic, and antiandrogenic activities, suggesting that higher localized activity at sites with known natural gas–related spills surrounding the river might be contributing to the multiple receptor activities observed in this water source. The majority of water samples collected from sites in a drilling-dense region of Colorado exhibited more estrogenic, antiestrogenic, or antiandrogenic activities than reference sites with limited nearby drilling operations. Our data suggest that natural gas drilling operationsmayresult in elevated endocrine-disrupting chemical activity in surface and ground water.

  7. Lithium content in potable water, surface water, ground water, and mineral water on the territory of Republic of Macedonia

    Directory of Open Access Journals (Sweden)

    Vesna Kostik

    2014-07-01

    Full Text Available The aim of this study was to determine lithium concentration in potable water, surface water, ground, and mineral water on the territory of the Republic of Macedonia. Water samples were collected from water bodies such as multiple public water supply systems located in 13 cities, wells boreholes located in 12 areas, lakes and rivers located in three different areas. Determination of lithium concentration in potable water, surface water was performed by the technique of inductively coupled plasma-mass spectrometry, while in ground water samples from wells boreholes and mineral waters with the technique of ion chromatography. The research shows that lithium concentration in potable water ranging from 0.1 to 5.2 μg/L; in surface water from 0.5 to 15.0 μg/L; ground water from wells boreholes from 16.0 to 49.1 μg/L and mineral water from 125.2 to 484.9 μg/L. Obtained values are in accordance with the relevant international values for the lithium content in water.

  8. Experimental Determination of Drag Modifications Due to Elastic Compliant Surfaces Using Quantitative Visual Techniques.

    Science.gov (United States)

    1988-04-27

    developed in the 5.49 mn by 0.4572 m by 0.1524 m test section of a recirculating liquid flow facility, in which deodorized kerosene was used as the...pulses. The aluminum and gelatin surfaces were reflective enough to result in a sharp reflection of the photochromic time line. The point at which the

  9. Investigation of reasons for small changes in energy of UCN due to their interaction with surface

    CERN Document Server

    Lychagin, E V; Nekhaev, G V; Strelkov, A V; Kartashov, D G; Nesvizhevsky, V V

    2002-01-01

    The nature of the phenomenon of small changes in energy of ultracold neutrons (UCN) has been investigated. This phenomenon occurs during collisions of UCN with a surface, which increase the UCN energy by approx 10 sup - sup 7 eV with a probability of 10 sup - sup 8 -10 sup - sup 5 per collision. Such neutrons are named VUCN. It was observed that the preliminary warming up of samples at 500-600 K leads to an increase of the small heating probability P sub V sub U sub C sub N by at least a factor of 100 for a surface of stainless steel and by a factor of 10 for a copper surface. Extremely intensive UCN small heating by a diamond nanopowder has been observed for the first time. The spectrum of these VUCN and the temperature dependence of their heating probability P sub V sub U sub C sub N are similar to those measured earlier for stainless steel, beryllium, and copper. It is not observed small UCN heating, nor nanoparticles on a monocrystalline sapphire surface. That leads to the conclusion that VUCN are produce...

  10. Assessment of Cold Welding Between Separable Contact Surfaces Due to Impact and Fretting under Vacuum

    Science.gov (United States)

    Merstallinger, A.; Sales, M.; Semerad, E.; Dunn, B. D.

    2009-11-01

    A common failure mode seen during the testing and operation of spacecraft is termed "cold welding". European laboratories refer to this as "adhesion", "sticking" or "stiction". This publication is intended to provide the space community with the most recent understanding of the phenomenon of "cold welding" in relation to spacecraft mechanisms with separable contact surfaces. It presents some basic theory and describes a test method and the required equipment. Cold welding between two contacting surfaces can occur under conditions of impact or fretting. These surfaces may be bare metals, or inorganically or organically coated metals and their alloys. Standard procedures for quantifying the propensity of material surface pairs to cold weld to each other are proposed. Of particular interest will be the contact data of different materials, which are presented in numerical form and as tables summarising contacts between materials that can be either recommended or considered unsuitable for use under vacuum. The data have been compiled in a database that can be accessed online.

  11. Quantification of the advected CO2 concentration due to upstream surface fluxes in aircraft vertical profiles

    Science.gov (United States)

    Font, A.; Morguí, J.-A.; Curcoll, R.; Rodó, X.

    2009-04-01

    A model framework which couples the Lagrangian Particle Dispersion Model FLEXPART (LPDM) with the new global surface flux inversion CarbonTracker from NOAA-ESRL (2007B release) is used to quantify the advected CO2 concentration from outbound surface fluxes to measured vertical profiles carried out during different seasons in 2006 at La Muela site in Spain (LMU; 41.60°N, 1.1°W). The Lagrangian Particle Dispersion Model FLEXPART (LPDM) calculates the influence of surface CO2 fluxes upwind of the study area, allowing us to identify those sources or sink areas that strongly modify the CO2 content of air masses that arrives at different altitudes of measured profiles. CarbonTracker is a new assimilation system that informs of global carbon fluxes at 1°x1° at 3 hours resolution. Coupling LPDM results with surface fluxes allows assessing the net CO2 contribution of identified areas to measured concentrations along the profiles above a reference or background concentration. Furthermore, it allows the quantification of the percentage of each component flux (biospheric, anthropogenic and oceanic) to each vertical layer. At LMU, biospheric fluxes account ~70% of total CO2 advection; fossil fuel ~25%; and ~5% is attributed to the oceanic ones. By far, late spring and summer profiles are largely influence by the biospheric component (~90%). Finally, the CO2 concentration above the background value of profiles measured on 22nd February, 13th October and 30th November 2006 are well explained by the advection of upstream surface fluxes. In other profiles examined, the variation of CO2 along the profile is partially explained by the advection of CO2 outbound fluxes.

  12. Electromagnetic fields due to a horizontal electric dipole antenna laid on the surface of a two-layer medium

    Science.gov (United States)

    Tsang, L.; Kong, J. A.

    1974-01-01

    With applications to geophysical subsurface probings, electromagnetic fields due to a horizontal electric dipole laid on the surface of a two-layer medium are solved by a combination of analytic and numerical methods. Interference patterns are calculated for various layer thickness. The results are interpreted in terms of normal modes, and the accuracies of the methods are discussed.

  13. A spectral formalism for computing three-dimensional deformations due to surface loads. 1: Theory

    Science.gov (United States)

    Mitrovica, J. X.; Davis, J. L.; Shapiro, I. I.

    1994-01-01

    We outline a complete spectral formalism for computing high spatial resolution three-dimensional deformations arising from the surface mass loading of a spherically symmetric planet. The main advantages of the formalism are that all surface mass loads are always described using a consistent mathematical representation and that calculations of deformation fields for various spatial resolutions can be performed by simpley altering the spherical harmonic degree truncation level of the procedure. The latter may be important when incorporating improved observational constraints on a particular surface mass load, when considering potential errors in the computed field associated with mass loading having a spatial scale unresolved by the observational constraints, or when treating a number of global surface mass loads constrained with different spatial resolutions. The advantages do not extend to traditional 'Green's function' approaches which involve surface element discretizations of the global mass loads. Another advantage of the spectral formalism, over the Green's function approach, is that a posteriori analyses of the computed deformation fields are easily performed. In developing the spectral formalism, we consider specific cases where the Earth's mantle is assumed to respond as an elastic, slightly anelastic, or linear viscoelastic medium. In the case of an elastic or slightly anelastic mantle rheology the spectral response equations incorporate frequency dependent Love numbers. The formalism can therefore be used, for example, to compute the potentially resonant deformational response associated with the free core nutation and Chandler wobble eigenfunctions. For completeness, the spectral response equations include both body forces, as arise from the gravitational attraction of the Sun and the Moon, and surface mass loads. In either case, and for both elastic and anelastic mantle rheologies, we outline a pseudo-spectral technique for computing the ocean

  14. The potential surface in the ground electronic state of HCP with the isomerization process: the validity of calculating potential surface with DFT methods

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The density functional theory (DFT) provides us an effective way to calculate large cluster systems with moderate computational demands. We calculate potential energy surfaces (PES) with several different approaches of DFT. The PES in the ground electronic state are related to HCP's isomerization process. The calculated PES are compared with the “experimental” PES obtained by fitting from the experimental vibrational spectra and that given by the “accurate” quantum chemistry calculation with more expensive computations. The comparisons show that the potential surfaces calculated with DFT methods can reach the accuracy of less than 0.1 eV.

  15. Decay of the Greenland Ice Sheet due to surface-meltwater-induced acceleration of basal sliding

    CERN Document Server

    Greve, Ralf

    2009-01-01

    Simulations of the Greenland Ice Sheet are carried out with a high-resolution version of the ice-sheet model SICOPOLIS for several global-warming scenarios for the period 1990-2350. In particular, the impact of surface-meltwater-induced acceleration of basal sliding on the stability of the ice sheet is investigated. A parameterization for the acceleration effect is developed for which modelled and measured mass losses of the ice sheet in the early 21st century agree well. The main findings of the simulations are: (i) the ice sheet is generally very susceptible to global warming on time-scales of centuries, (ii) surface-meltwater-induced acceleration of basal sliding leads to a pronounced speed-up of ice streams and outlet glaciers, and (iii) this ice-dynamical effect accelerates the decay of the Greenland Ice Sheet as a whole significantly, but not catastrophically, in the 21st century and beyond.

  16. Surface uplift and time-dependent seismic hazard due to fluid-injection in eastern Texas

    Science.gov (United States)

    Shirzaei, M.; Ellsworth, W. L.; Tiampo, K. F.; González, P. J.; Manga, M.

    2015-12-01

    US states such as Texas and Oklahoma that produce high-volumes of unconventional oil and gas, are facing a sharp increase in seismicity. Observations of the associated surface deformation and accompanying physical models that unequivocally link the seismicity and waste water injection are scarce. Here, we find that the waste water injection in eastern Texas causes uplift, detectable using radar interferometric data. Combining the uplift and injection data through a poroelastic model allows for the resolution of a complex crustal distribution of hydraulic conductivity and pore pressure. We find that the ~5 years pore pressure increase is capable of triggering the 17 May 2012, Mw 4.8 earthquake, the largest event recorded in east Texas. This study shows that surface deformation data are vital in order to constrain the spatiotemporal variations of the stress field in the vicinity of injection sites.

  17. FREQUENCY SHIFTS OF RESONANT MODES OF THE SUN DUE TO NEAR-SURFACE CONVECTIVE SCATTERING

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, J.; Hanasoge, S.; Antia, H. M. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai-400005 (India)

    2015-06-20

    Measurements of oscillation frequencies of the Sun and stars can provide important independent constraints on their internal structure and dynamics. Seismic models of these oscillations are used to connect structure and rotation of the star to its resonant frequencies, which are then compared with observations, the goal being that of minimizing the difference between the two. Even in the case of the Sun, for which structure models are highly tuned, observed frequencies show systematic deviations from modeled frequencies, a phenomenon referred to as the “surface term.” The dominant source of this systematic effect is thought to be vigorous near-surface convection, which is not well accounted for in both stellar modeling and mode-oscillation physics. Here we bring to bear the method of homogenization, applicable in the asymptotic limit of large wavelengths (in comparison to the correlation scale of convection), to characterize the effect of small-scale surface convection on resonant-mode frequencies in the Sun. We show that the full oscillation equations, in the presence of temporally stationary three-dimensional (3D) flows, can be reduced to an effective “quiet-Sun” wave equation with altered sound speed, Brünt–Väisäla frequency, and Lamb frequency. We derive the modified equation and relations for the appropriate averaging of 3D flows and thermal quantities to obtain the properties of this effective medium. Using flows obtained from 3D numerical simulations of near-surface convection, we quantify their effect on solar oscillation frequencies and find that they are shifted systematically and substantially. We argue therefore that consistent interpretations of resonant frequencies must include modifications to the wave equation that effectively capture the impact of vigorous hydrodynamic convection.

  18. Low-Temperature Softening Due to Vacancy Orbital with Γ8 Quartet Ground State in Boron-Doped Floating Zone Silicon

    Science.gov (United States)

    Baba, Shotaro; Akatsu, Mitsuhiro; Mitsumoto, Keisuke; Komatsu, Satoru; Horie, Kunihiko; Nemoto, Yuichi; Yamada-Kaneta, Hiroshi; Goto, Terutaka

    2013-08-01

    We have carried out low-temperature ultrasonic measurements using shear-mode ultrasound to clarify the quantum state of a vacancy orbital in boron-doped silicon grown by the floating zone (FZ) method. The elastic constants (C11-C12)/2 and C44 of the transverse mode exhibit considerable softening below 2 and 5 K down to the base temperature of 30 mK, respectively. The elastic constant C44 measured by the three ultrasonic modes (kx,uy), (kz,ux), and (kx,uz) shows the different magnetic field dependences among the configurations under applied magnetic fields along the z-axis. The elastic softening and the magnetic field dependence of the elastic constants are accounted for by the quadrupole susceptibility based on the energy level scheme of the vacancy orbital with a Γ8 quartet ground state and Γ7 doublet excited state located at an energy of 1 K. The difference in C44 between the two ultrasonic modes (kz,ux) and (kx,uz) at fields along the z-axis indicates that the Γ8 quartet ground state is slightly split by local strain in the silicon sample. The quantum state of the vacancy orbital is expected to be sensitive to strain because of the extremely large quadrupole-strain coupling energy of gΓ≈ 105 K due to the extensively spreading orbital radius of r≈ 1 nm. The differences in variation of the low-temperature softening and magnetic field dependence among eight samples cut out from different locations of the present boron-doped FZ silicon ingot evidence the inhomogeneous distribution of the vacancy concentration.

  19. Surface aerosol and rehabilitation properties of ground-level atmosphere in the mountains of the North Caucasus

    Science.gov (United States)

    Reps, Valentina; Efimenko, Natalia; Povolotskaya, Nina; Abramtsova, Anna; Ischenko, Dmitriy; Senik, Irina; Slepikh, Victor

    2017-04-01

    The rehabilitative properties (RP) of ground-level atmosphere (GA) of Russian resorts are considered as natural healing resources and received state legal protection [1]. Due to global urbanization the chemical composition and particle size distribution of the surface aerosol are changing rapidly. However, the influence of surface aerosol on the RP of GA has been insufficiently studied. At the resort region of the North Caucasus complex monitoring (aerosol, trace gases NOx, CO, O3, CH4; periodically - heavy metals) is performed at two high levels (860 masl - a park zone of a large mountain resort, 2070 masl - alpine grassland, the net station). The results of the measurements are used in programs of bioclimatic, landscape and medical monitoring to specify the influence of aerosol on rehabilitation properties of the environment and human adaptative reserves. The aerosol particles of size range 500-1000 nm are used as a marker of the pathogenic effect of aerosol [2]. In the conditions of regional urbanization and complicated mountain atmospheric circulation the influence of aerosol on RP of GA and the variability of heart rhythm with the volunteers at different heights were investigated. At the height of 860 masl (urbanized resort) there have been noticed aerosol variations in the range of 0,04-0,35 particles/cm3 (slightly aerosol polluted), in mountain conditions - background pollution aerosol level. The difference of bioclimatic conditions at the specified high-rise levels has been referred to the category of contrasts. The natural aero ionization ∑(N+)+(N-) varied from 960 ion/cm3 to 1460 ion/cm3 in the resort park (860 m); from 1295 ion/cm3 to 4850 ion/cm3 on the Alpine meadow (2070 m); from 1128 ion/cm3 to 3420 ion/cm3 - on the tested site near the edge of the pinewood (1720 m). In the group of volunteers the trip from low-hill terrain zone (860 m) to the lower zone of highlands (2070 m) caused the activation of neuro and humoral regulation, vegetative and

  20. Convection due to surface-tension gradients. [in reduced gravity spacecraft environments

    Science.gov (United States)

    Ostrach, S.

    1978-01-01

    The use of dimensionless parameters to study fluid motions that could occur in a reduced-gravity environment is discussed. The significance of the Marangoni instability is considered, and the use of dimensionless parameters to investigate problems such as thermo and diffusocapillary flows is described. Characteristics of fluid flow in space are described, and the relation and interaction of motions due to capillarity and buoyancy is examined.

  1. Comparison of buried soil sensors, surface chambers and above ground measurements of carbon dioxide fluxes

    Science.gov (United States)

    Soil carbon dioxide (CO2) flux is an important component of the terrestrial carbon cycle. Accurate measurements of soil CO2 flux aids determinations of carbon budgets. In this study, we investigated soil CO2 fluxes with time and depth and above ground CO2 fluxes in a bare field. CO2 concentrations w...

  2. Areal-Averaged Spectral Surface Albedo in an Atlantic Coastal Area: Estimation from Ground-Based Transmission

    Directory of Open Access Journals (Sweden)

    Evgueni Kassianov

    2017-07-01

    Full Text Available Tower-based data combined with high-resolution satellite products have been used to produce surface albedo at various spatial scales over land. Because tower-based albedo data are available at only a few sites, surface albedos using these combined data are spatially limited. Moreover, tower-based albedo data are not representative of highly heterogeneous regions. To produce areal-averaged and spectrally-resolved surface albedo for regions with various degrees of surface heterogeneity, we have developed a transmission-based retrieval and demonstrated its feasibility for relatively homogeneous land surfaces. Here, we demonstrate its feasibility for a highly heterogeneous coastal region. We use the atmospheric transmission measured during a 19-month period (June 2009–December 2010 by a ground-based Multi-Filter Rotating Shadowband Radiometer (MFRSR at five wavelengths (0.415, 0.5, 0.615, 0.673 and 0.87 µm at the Department of Energy’s Atmospheric Radiation Measurement (ARM Mobile Facility (AMF site located on Graciosa Island. We compare the MFRSR-retrieved areal-averaged surface albedo with albedo derived from Moderate Resolution Imaging Spectroradiometer (MODIS observations, and also a composite-based albedo. We demonstrate that these three methods produce similar spectral signatures of surface albedo; however, the MFRSR-retrieved albedo, is higher on average (≤0.04 than the MODIS-based areal-averaged surface albedo and the largest difference occurs in winter.

  3. Comparison of MTI and Ground Truth Sea Surface Temperatures at Nauru

    Energy Technology Data Exchange (ETDEWEB)

    Kurzeja, R.

    2002-09-05

    This report evaluates MTI-derived surface water temperature near the tropical Pacific island of Nauru. The MTI sea-surface temperatures were determined by the Los Alamos National Laboratory based on the robust retrieval.

  4. Rotating flow of a nanofluid due to an exponentially stretching surface with suction

    Science.gov (United States)

    Salleh, Siti Nur Alwani; Bachok, Norfifah; Arifin, Norihan Md

    2017-08-01

    An analysis of the rotating nanofluid flow past an exponentially stretched surface with the presence of suction is studied in this work. Three different types of nanoparticles, namely, copper, titania and alumina are considered. The system of ordinary differential equations is computed numerically using a shooting method in Maple software after being transformed from the partial differential equations. This transformation has considered the similarity transformations in exponential form. The physical effect of the rotation, suction and nanoparticle volume fraction parameters on the rotating flow and heat transfer phenomena is investigated and has been described in detail through graphs. The dual solutions are found to appear when the governing parameters reach a certain range.

  5. Surface roughness due to residual ice in the use of low power deicing systems

    Science.gov (United States)

    Shin, Jaiwon; Bond, Thomas H.

    1993-01-01

    Thicknesses of residual ice are presented to provide information on surface contamination and associated roughness during deicing events. Data was obtained from low power ice protection systems tests conducted in the Icing Research Tunnel at NASA Lewis Research Center (LeRC) with nine different deicing systems. Results show that roughness associated with residual ice is not characterized by uniformly distributed roughness. Results also show that deicing systems require a critical mass of ice to generate a sufficient expelling force to remove the ice.

  6. Decay of the Greenland Ice Sheet due to surface-meltwater-induced acceleration of basal sliding

    OpenAIRE

    Greve, Ralf; SUGIYAMA, SHIN

    2009-01-01

    Simulations of the Greenland Ice Sheet are carried out with a high-resolution version of the ice-sheet model SICOPOLIS for several global-warming scenarios for the period 1990-2350. In particular, the impact of surface-meltwater-induced acceleration of basal sliding on the stability of the ice sheet is investigated. A parameterization for the acceleration effect is developed for which modelled and measured mass losses of the ice sheet in the early 21st century agree well. The main findings of...

  7. A NUMERICAL SIMULATION OF THE EFFECT ON CHINESE REGIONAL CLIMATE DUE TO SEASONAL VARIATION OF LAND SURFACE PARAMETERS (PART I)

    Institute of Scientific and Technical Information of China (English)

    孙健; 李维亮; 周秀骥

    2001-01-01

    Sensitivity experiment is an important method to study the effect on regional climate due to seasonal variation of land surface parameters. Using China Regional Climate Model (CRCM)nested in CCM1, we first simulate Chinese regional climate, then two numerical sensitivity experiments on the effect of vegetation and roughness length are made. The results show that:(1) If the vegetation is replaced with the monthly data of 1997, precipitation and land-surface temperature are both changed clearly, precipitation decreases and land surface temperature increases, but there is no regional correspondence between these changes. And the results are much better than the results when climate average vegetation was used in the CRCM. (2) If the roughness length is replaced with the monthly data of 1997, there is significant change on land surface temperature, and there is very good regional correspondence between these changes. But the effect on precipitation is very small.

  8. Force Restore Technique for Ground Surface Temperature and Moisture Content in a Dry Desert System

    NARCIS (Netherlands)

    Jacobs, A.F.G.; Heusinkveld, B.G.; Berkowicz, S.

    2000-01-01

    The level of the surface temperature as well as surface moisture content is important for the turbulent transports of sensible and latent heat, respectively, but this level is also crucial for the survival of shrubs, plants, insects, and small animals in a desert environment. To estimate the surface

  9. Large apparent electric size of solid-state nanopores due to spatially extended surface conduction.

    Science.gov (United States)

    Lee, Choongyeop; Joly, Laurent; Siria, Alessandro; Biance, Anne-Laure; Fulcrand, Rémy; Bocquet, Lydéric

    2012-08-08

    Ion transport through nanopores drilled in thin membranes is central to numerous applications, including biosensing and ion selective membranes. This paper reports experiments, numerical calculations, and theoretical predictions demonstrating an unexpectedly large ionic conduction in solid-state nanopores, taking its origin in anomalous entrance effects. In contrast to naive expectations based on analogies with electric circuits, the surface conductance inside the nanopore is shown to perturb the three-dimensional electric current streamlines far outside the nanopore in order to meet charge conservation at the pore entrance. This unexpected contribution to the ionic conductance can be interpreted in terms of an apparent electric size of the solid-state nanopore, which is much larger than its geometric counterpart whenever the number of charges carried by the nanopore surface exceeds its bulk counterpart. This apparent electric size, which can reach hundreds of nanometers, can have a major impact on the electrical detection of translocation events through nanopores, as well as for ionic transport in biological nanopores.

  10. Questa baseline and pre-mining ground-water quality investigation. 5. Well installation, water-level data, and surface- and ground-water geochemistry in the Straight Creek drainage basin, Red River Valley, New Mexico, 2001-03

    Science.gov (United States)

    Naus, Cheryl A.; McCleskey, R. Blaine; Nordstrom, D. Kirk; Donohoe, Lisa C.; Hunt, Andrew G.; Paillet, Frederick L.; Morin, Roger H.; Verplanck, Philip L.

    2005-01-01

    The U.S. Geological Survey, in cooperation with the New Mexico Environment Department, is investigating the pre-mining ground-water chemistry at the Molycorp molybdenum mine in the Red River Valley, northern New Mexico. The primary approach is to determine the processes controlling ground-water chemistry at an unmined, off-site, proximal analog. The Straight Creek drainage basin, chosen for this purpose, consists of the same quartz-sericite-pyrite altered andesitic and rhyolitic volcanic rock of Tertiary age as the mine site. The weathered and rugged volcanic bedrock surface is overlain by heterogeneous debris-flow deposits that interfinger with alluvial deposits near the confluence of Straight Creek and the Red River. Pyritized rock in the upper part of the drainage basin is the source of acid rock drainage (pH 2.8-3.3) that infiltrates debris-flow deposits containing acidic ground water (pH 3.0-4.0) and bedrock containing water of circumneutral pH values (5.6-7.7). Eleven observation wells were installed in the Straight Creek drainage basin. The wells were completed in debris-flow deposits, bedrock, and interfingering debris-flow and Red River alluvial deposits. Chemical analyses of ground water from these wells, combined with chemical analyses of surface water, water-level data, and lithologic and geophysical logs, provided information used to develop an understanding of the processes contributing to the chemistry of ground water in the Straight Creek drainage basin. Surface- and ground-water samples were routinely collected for determination of total major cations and selected trace metals; dissolved major cations, selected trace metals, and rare-earth elements; anions and alkalinity; and dissolved-iron species. Rare-earth elements were determined on selected samples only. Samples were collected for determination of dissolved organic carbon, mercury, sulfur isotopic composition (34S and 18O of sulfate), and water isotopic composition (2H and 18O) during

  11. Evaluation of Cavity Collapse and Surface Crater Formation at the Norbo Underground Nuclear Test in U8c, Nevada Nuclear Security Site, and the Impact on Stability of the Ground Surface

    Energy Technology Data Exchange (ETDEWEB)

    Pawloski, G A

    2012-06-18

    Lawrence Livermore National Laboratory (LLNL) Containment Program performed a review of nuclear test-related data for the Norbo underground nuclear test in U8c to assist in evaluating this legacy site as a test bed for application technologies for use in On-Site Inspections (OSI) under the Comprehensive Nuclear Test Ban Treaty. This request is similar to one made for the Salut site in U8c (Pawloski, 2012b). Review of the Norbo site is complicated because the test first exhibited subsurface collapse, which was not unusual, but it then collapsed to the surface over one year later, which was unusual. Of particular interest is the stability of the ground surface above the Norbo detonation point. Proposed methods for on-site verification include radiological signatures, artifacts from nuclear testing activities, and imaging to identify alteration to the subsurface hydrogeology due to the nuclear detonation. Aviva Sussman from the Los Alamos National Laboratory (LANL) has also proposed work at this site. Both proposals require physical access at or near the ground surface of specific underground nuclear test locations at the Nevada Nuclear Security Site (NNSS), formerly the Nevada Test Site (NTS), and focus on possible activities such as visual observation, multispectral measurements, and shallow and deep geophysical surveys.

  12. Evaluation of Cavity Collapse and Surface Crater Formation at the Salut Underground Nuclear Test in U20ak, Nevada National Security Site, and the Impact of Stability of the Ground Surface

    Energy Technology Data Exchange (ETDEWEB)

    Pawloski, G A

    2012-04-25

    At the request of Jerry Sweeney, the LLNL Containment Program performed a review of nuclear test-related data for the Salut underground nuclear test in U20ak to assist in evaluating this legacy site as a test bed for application technologies for use in On-Site Inspections (OSI) under the Comprehensive Nuclear Test Ban Treaty. Review of the Salut site is complicated because the test experienced a subsurface, rather than surface, collapse. Of particular interest is the stability of the ground surface above the Salut detonation point. Proposed methods for on-site verification include radiological signatures, artifacts from nuclear testing activities, and imaging to identify alteration to the subsurface hydrogeologogy due to the nuclear detonation. Sweeney's proposal requires physical access at or near the ground surface of specific underground nuclear test locations at the Nevada Nuclear Test Site (NNSS, formerly the Nevada Test Site), and focuses on possible activities such as visual observation, multispectral measurements, and shallow, and deep geophysical surveys.

  13. Second-Order Nonlinearity in Triangular Lattice Perforated Gold Film due to Surface Plasmas Resonance

    Directory of Open Access Journals (Sweden)

    Renlong Zhou

    2014-01-01

    Full Text Available We have studied the excitation second-order nonlinearity through a triangular lattice perforated gold film instead of square lattice in many papers. Under the excitation of surface plasmas resonance effect, the second order nonlinearity exists in the noncentrosymmetric split-ring resonators arrays. Reflection of fundamental frequency wave through a triangular lattice perforated gold film is obtained. We also described the second harmonic conversion efficiencies in the second order nonlinear optical process with the spectra. Moreover, the electric field distributions of fundamental frequency above the gold film region are calculated. The light propagation through the holes results in the enhancement of the second order nonlinearity including second harmonic generation as well as the sum (difference frequency generation.

  14. Failure of man-made cavities in salt and surface subsidence due to sulfur mining

    Energy Technology Data Exchange (ETDEWEB)

    Coates, G.K.; Lee, C.A.; McClain, W.C.; Senseny, P.E.

    1981-01-01

    An engineering data base relevant to subsidence due to sulfur mining and to structural failure of cavities in salt is established, evaluated and documented. Nineteen failure events are discussed. Based on these documented failure events, capabilities of and inputs to a mathematical model of cavity failure are determined. Two failure events are adequately documented for use in model verification studies. A conclusion of this study that is pertinent to the Strategic Petroleum Reserve is that cavity failures in dome salt are fairly rare, but that as the number of large cavities (especially those having large roof spans) increases, failures will probably be more common unless stability and failure mechanisms of cavities are better understood.

  15. Scientific Ground of a New Optical Device for Contactless Measurement of the Small Spatial Displacements of Control Object Surfaces

    Science.gov (United States)

    Miroshnichenko, I. P.; Parinov, I. A.

    2017-06-01

    It is proposed the computational-experimental ground of newly developed optical device for contactless measurement of small spatial displacements of control object surfaces based on the use of new methods of laser interferometry. The proposed device allows one to register linear and angular components of the small displacements of control object surfaces during the diagnosis of the condition of structural materials for forced elements of goods under exploring by using acoustic non-destructive testing methods. The described results are the most suitable for application in the process of high-precision measurements of small linear and angular displacements of control object surfaces during experimental research, the evaluation and diagnosis of the state of construction materials for forced elements of goods, the study of fast wave propagation in layered constructions of complex shape, manufactured of anisotropic composite materials, the study of damage processes in modern construction materials in mechanical engineering, shipbuilding, aviation, instrumentation, power engineering, etc.

  16. Construction and Testing of Broadband High Impedance Ground Planes (HIGPS) for Surface Mount Antennas

    Science.gov (United States)

    2008-03-01

    mushrooms (with side lengths of 7.6mm). Larger mushrooms (with side lengths of 16mm) were located to the edges of the substrate . The resulting...thickness and substrate permittivity are two of the main design parameters. But these parameters have production constraints, since they are ordered off...plane designs as a meta- substrate for a broadband bow-tie antenna were presented. Consequently, the high impedance ground plane provided a suitable

  17. Near-surface seismic velocity changes in a salt-dominated environment due to shaking and thermal stressing

    Science.gov (United States)

    Richter, Tom; Sens-Schönfelder, Christoph; Kind, Rainer; Asch, Günter

    2014-05-01

    We report on results from a seismic station of the Integrated Plate Boundary Observatory Chile (IPOC) showing a superior sensitivity of seismic velocity changes in the surrounding medium to shaking and temperature. 5 years of daily autocorrelations of the IPOC network are analyzed with passive image interferometry. Due to the particular geological conditions we observe a high sensitivity of the medium around the station near Patache (PATCX) resulting in annual periodic velocity variations and temporary velocity reductions induced by ground shaking. We observe a linear relationship between the amplitude of the velocity reductions and the peak ground acceleration (PGA) of nearby earthquakes at station PATCX. Although velocity reductions are also observed at other stations of the IPOC array for the Mw 7.7 Tocopilla earthquake a clear relationship between the PGA of this earthquake and the induced velocity reductions at the different stations is not visible. Furthermore, we observe velocity variations with an annual and daily period. We present different arguments that these periodic changes are caused by variations of the atmospheric temperature. In this context we construct a model that starts at observed temperature variations and evaluates thermal stresses induced by the temperature gradients. Using radiative transfer based sensitivity kernels and third order elastic constants we relate the distribution of thermal stress in the subsurface to observable time shifts of coda waves. The model is able to reproduce the major features confirming that stress changes in the subsurface can be detected with noise based monitoring.

  18. Use of ground-water reservoirs for storage of surface water in the San Joaquin Valley, California

    Science.gov (United States)

    Davis, G.H.; Lofgren, B.E.; Mack, Seymour

    1964-01-01

    The San Joaquin Valley includes roughly the southern two-thirds of the Central Valley of California, extending 250 miles from Stockton on the north to Grapevine at the foot of the Tehachapi Mountains. The valley floor ranges in width from 25 miles near Bakersfield to about 55 miles near Visalia; it has a surface area of about 10,000 square miles. More than one-quarter of all the ground water pumped for irrigation in the United States is used in this highly productive valley. Withdrawal of ground water from storage by heavy pumping not only provides a needed irrigation water supply, but it also lowers the ground-water level and makes storage space available in which to conserve excess water during periods of heavy runoff. A storage capacity estimated to be 93 million acre-feet to a depth of 200 feet is available in this ground-water reservoir. This is about nine times the combined capacity of the existing and proposed surface-water reservoirs in the San Joaquin Valley under the California Water Plan. The landforms of the San Joaquin Valley include dissected uplands, low plains and fans, river flood plains and channels, and overflow lands and lake bottoms. Below the land surface, unconsolidated sediments derived from the surrounding mountain highlands extend downward for hundreds of feet. These unconsolidated deposits, consisting chiefly of alluvial deposits, but including some widespread lacustrine sediments, are the principal source of ground water in the valley. Ground water occurs under confined and unconfined conditions in the San Joaquin Valley. In much of the western, central, and southeastern parts of the valley, three distinct ground-water reservoirs are present. In downward succession these are 1) a body of unconfined and semiconfined fresh water in alluvial deposits of Recent, Pleistocene, and possibly later Pliocene age, overlying the Corcoran clay member of the Tulare formation; 2) a body of fresh water confined beneath the Corcoran clay member, which

  19. Elevation change of the Greenland Ice Sheet due to surface mass balance and firn processes, 1960-2014

    Science.gov (United States)

    Kuipers Munneke, P.; Ligtenberg, S. R. M.; Noël, B. P. Y.; Howat, I. M.; Box, J. E.; Mosley-Thompson, E.; McConnell, J. R.; Steffen, K.; Harper, J. T.; Das, S. B.; van den Broeke, M. R.

    2015-11-01

    Observed changes in the surface elevation of the Greenland Ice Sheet are caused by ice dynamics, basal elevation change, basal melt, surface mass balance (SMB) variability, and by compaction of the overlying firn. The last two contributions are quantified here using a firn model that includes compaction, meltwater percolation, and refreezing. The model is forced with surface mass fluxes and temperature from a regional climate model for the period 1960-2014. The model results agree with observations of surface density, density profiles from 62 firn cores, and altimetric observations from regions where ice-dynamical surface height changes are likely small. In areas with strong surface melt, the firn model overestimates density. We find that the firn layer in the high interior is generally thickening slowly (1-5 cm yr-1). In the percolation and ablation areas, firn and SMB processes account for a surface elevation lowering of up to 20-50 cm yr-1. Most of this firn-induced marginal thinning is caused by an increase in melt since the mid-1990s and partly compensated by an increase in the accumulation of fresh snow around most of the ice sheet. The total firn and ice volume change between 1980 and 2014 is estimated at -3295 ± 1030 km3 due to firn and SMB changes, corresponding to an ice-sheet average thinning of 1.96 ± 0.61 m. Most of this volume decrease occurred after 1995. The computed changes in surface elevation can be used to partition altimetrically observed volume change into surface mass balance and ice-dynamically related mass changes.

  20. Enhanced spin Seebeck effect signal due to spin-momentum locked topological surface states

    Science.gov (United States)

    Jiang, Zilong; Chang, Cui-Zu; Masir, Massoud Ramezani; Tang, Chi; Xu, Yadong; Moodera, Jagadeesh S.; MacDonald, Allan H.; Shi, Jing

    2016-05-01

    Spin-momentum locking in protected surface states enables efficient electrical detection of magnon decay at a magnetic-insulator/topological-insulator heterojunction. Here we demonstrate this property using the spin Seebeck effect (SSE), that is, measuring the transverse thermoelectric response to a temperature gradient across a thin film of yttrium iron garnet, an insulating ferrimagnet, and forming a heterojunction with (BixSb1-x)2Te3, a topological insulator. The non-equilibrium magnon population established at the interface can decay in part by interactions of magnons with electrons near the Fermi energy of the topological insulator. When this decay channel is made active by tuning (BixSb1-x)2Te3 into a bulk insulator, a large electromotive force emerges in the direction perpendicular to the in-plane magnetization of yttrium iron garnet. The enhanced, tunable SSE which occurs when the Fermi level lies in the bulk gap offers unique advantages over the usual SSE in metals and therefore opens up exciting possibilities in spintronics.

  1. Modeling nonlinear errors in surface electromyography due to baseline noise: a new methodology.

    Science.gov (United States)

    Law, Laura Frey; Krishnan, Chandramouli; Avin, Keith

    2011-01-01

    The surface electromyographic (EMG) signal is often contaminated by some degree of baseline noise. It is customary for scientists to subtract baseline noise from the measured EMG signal prior to further analyses based on the assumption that baseline noise adds linearly to the observed EMG signal. The stochastic nature of both the baseline and EMG signal, however, may invalidate this assumption. Alternately, "true" EMG signals may be either minimally or nonlinearly affected by baseline noise. This information is particularly relevant at low contraction intensities when signal-to-noise ratios (SNR) may be lowest. Thus, the purpose of this simulation study was to investigate the influence of varying levels of baseline noise (approximately 2-40% maximum EMG amplitude) on mean EMG burst amplitude and to assess the best means to account for signal noise. The simulations indicated baseline noise had minimal effects on mean EMG activity for maximum contractions, but increased nonlinearly with increasing noise levels and decreasing signal amplitudes. Thus, the simple baseline noise subtraction resulted in substantial error when estimating mean activity during low intensity EMG bursts. Conversely, correcting EMG signal as a nonlinear function of both baseline and measured signal amplitude provided highly accurate estimates of EMG amplitude. This novel nonlinear error modeling approach has potential implications for EMG signal processing, particularly when assessing co-activation of antagonist muscles or small amplitude contractions where the SNR can be low.

  2. The change in mutagenicity:study on surface water of Qiantang River due to tide

    Institute of Scientific and Technical Information of China (English)

    WuNX; YangYM

    2002-01-01

    The Qiangtang River lies in Zhejiang Province of China.In this study,the genotoxicity of surface water samples from five sites along the river were detected using Ames test(TA98,TA100±S9),comet(SCGE) test and cytokinesis-block micronucleus(CBMN) tesdt(-S9) in the human peripheral lymphocytes in vitro.The results indicated that in upstream samples (first site) during falling-tide was found slight mutagenicity in TA98 strain with S9 and without S9.The mutagenicity of samples from the second to the fifth site was gradually stronger.Except the first site sample,the micronucleated cell rates of the other four samples during falling-tide significantly increased in CBMN test,and the extent of migration of DNA fragments of the four samples was found to be significantly different from control group.In the upstream(first site) samples during flow-tide were found no mutagen by three short-term tests.But the other four samples were found more stronger mutagenicity in TA98 strain with S9 than that during falling-tide.The micronucleated cell rates and the extent of migration of DNA fragments of the samples were sdignificantly high than that during falling-tide too.

  3. Colour and chemical changes of the lime wood surface due to CO2 laser thermal modification

    Science.gov (United States)

    Kubovský, Ivan; Kačík, František

    2014-12-01

    We studied colour and main wood components changes of lime wood caused by CO2 laser beam irradiation. The dry surface of lime wood (Tilia vulgaris L.) was irradiated with the CO2 laser beam (wavelength of 10.6 μm) at different exposures (expressed as the irradiation dose). Colour changes were monitored by the spectrophotometer, chemical changes were observed by the ATR-FTIR spectroscopy and carbohydrates were analysed by the HPLC method. With the growth of the irradiation dose (from 8.1 to 28.7 J cm-2) lightness (ΔL*) decrease and increase of the total colour difference (ΔE*) were observed. Higher values of the input energy lead to accelerating the mutual reaction of the functional groups resulting in the subsequent condensation of lignin. The total decrease in saccharides at the highest irradiation dose reaches 27.39% of the initial amount of saccharides in the reference sample. We have observed degradation and loss of hemicelluloses.

  4. Modeling viscoelastic deformation of the earth due to surface loading by commercial finite element package - ABAQUS

    Science.gov (United States)

    Kit Wong, Ching; Wu, Patrick

    2017-04-01

    Wu (2004) developed a transformation scheme to model viscoelatic deformation due to glacial loading by commercial finite element package - ABAQUS. Benchmark tests confirmed that this method works extremely well on incompressible earth model. Bangtsson & Lund (2008),however, showed that the transformation scheme would lead to incorrect results if compressible material parameters are used. Their study implies that Wu's method of stress transformation is inadequate to model the load induced deformation of a compressible earth under the framework of ABAQUS. In light of this, numerical experiments are carried out to find if there exist other methods that serve this purpose. All the tested methods are not satisfying as the results failed to converge through iterations, except at the elastic limit. Those tested methods will be outlined and the results will be presented. Possible reasons of failure will also be discussed. Bängtsson, E., & Lund, B. (2008). A comparison between two solution techniques to solve the equations of glacially induced deformation of an elastic Earth. International journal for numerical methods in engineering, 75(4), 479-502. Wu, P. (2004). Using commercial finite element packages for the study of earth deformations, sea levels and the state of stress. Geophysical Journal International, 158(2), 401-408.

  5. DEM Development from Ground-Based LiDAR Data: A Method to Remove Non-Surface Objects

    Directory of Open Access Journals (Sweden)

    Maneesh Sharma

    2010-11-01

    Full Text Available Topography and land cover characteristics can have significant effects on infiltration, runoff, and erosion processes on watersheds. The ability to model the timing and routing of surface water and erosion is affected by the resolution of the digital elevation model (DEM. High resolution ground-based Light Detecting and Ranging (LiDAR technology can be used to collect detailed topographic and land cover characteristic data. In this study, a method was developed to remove vegetation from ground-based LiDAR data to create high resolution DEMs. Research was conducted on intensively studied rainfall–runoff plots on the USDA-ARS Walnut Gulch Experimental Watershed in Southeast Arizona. LiDAR data were used to generate 1 cm resolution digital surface models (DSM for 5 plots. DSMs created directly from LiDAR data contain non-surface objects such as vegetation cover. A vegetation removal method was developed which used a slope threshold and a focal mean filter method to remove vegetation and create bare earth DEMs. The method was validated on a synthetic plot, where rocks and vegetation were added incrementally. Results of the validation showed a vertical error of ±7.5 mm in the final DEM.

  6. Geochemistry of the surface and ground waters of the upper bassin of the river Llobregat

    Directory of Open Access Journals (Sweden)

    Freixes, A.

    1996-12-01

    Full Text Available In this work the main geochemical characteristics of the surface and ground waters of the Upper basin of the River Llobregat are described and, discussed. The water samples analysed reveal sharply contrasting characteristics. In both the Fonts del Llobregat and River Bastareny catchments, calcium bicarbonated waters with a low mineral content clearly predominate. However, in the catchment of the River Arija, although the waters of the upper course and the main tributaries are also calcium bicarbonated, it is worth noting that at the confluence with the River Llobregat calcium sulphated water is found. The catchment of the River Saldes shows a greater heterogeneity, with calcium bicarbonated, sodium chloridized and calcium sulphated waters, and thus at the confluence with the River Llobregat the water is sodium-calcium bicarbonated-sulphated. Principal components analysis enables us to arrive at a synthesis which clearly explains these characteristics. These results are fundamentally interpreted on the basis of the lithologies drained by the different watercourses.

    [es] En el presente estudio se presentan y discuten las principales características geoquímicas de las aguas superficiales y subterráneas de la Alta cuenca del río Llobregat hasta la entrada del río al embalse de La Baells. El conjunto de aguas analizadas presentan características muy contrastadas. Así, tanto en la subcuenca de las fuentes del Llobregat como en la del río Bastareny predominan las aguas bicarbonatadas cálcicas poco mineralizadas. En la subcuenca del río Arija, sí bien las aguas del curso alto y las de los principales afluentes también son bicarbonatadas cálcicas, destaca el hecho de que en la confluencia con el río Llobregat el agua es sulfatada cálcica. La subcuenca del río Saldes es la que presenta una mayor heterogeneidad, con aguas bicarbonatadas cálcicas, cloruradas sódicas y sulfatadas cálcicas, las cuales provocan que en la confluencia

  7. Security Problem of Wind Farm Booster Station Grounding Grid due to Lighting Stroke%雷击引起风电场升压站接地网安全性问题研究

    Institute of Scientific and Technical Information of China (English)

    曹学华; 夏文华; 房翔

    2015-01-01

    风力发电场升压站作为风电场的重要组成部分,因为风电场所处位置一般较为恶劣,易遭受雷电波入侵,给设备和人身带来一系列的威胁。首先结合一风电场升压站遭受雷击的案例,对雷电流泄放前及泄放中两个时间段内,地网及地表的瞬态电位差进行仿真计算,然后分析和考察地网导体的瞬态电位分布对直接连接在水平地网上的一次设备、二次设备或二次系统的绝缘和干扰的影响,以及地表电位分布对人员安全的影响,并提供相应的防护建议。%Wind power plant booster station is an important component of the wind farm. Due to the location of wind farms in general is relatively poor, it is vulnerable to the thunder electric wave, and will bring a series of threats to equipment and personal safety. Combined with a case that a wind power plant booster station is struck by lightning, the transient potential difference of the earth's surface and the ground net before and in the process of lightning discharge flow are simulated and calculated. The influence of transient potential distribution of the ground net conductor on the interference and insulation of the primary equipment and secondary equipment or the secondary system that are directly connected with the level-ground grids and the influence of the surface potential distribution on the personnel safety are also shown. Some protective suggestions are given as well.

  8. Water quality and ground-water/surface-water interactions along the John River near Anaktuvuk Pass, Alaska, 2002-2003

    Science.gov (United States)

    Moran, Edward H.; Brabets, Timothy P.

    2005-01-01

    The headwaters of the John River are located near the village ofAnaktuvuk Pass in the central Brooks Range of interior Alaska. With the recent construction of a water-supply system and a wastewater-treatment plant, most homes in Anaktuvuk Pass now have modern water and wastewater systems. The effluent from the treatment plant discharges into a settling pond near a tributary of the John River. The headwaters of the John River are adjacent to Gates of the Arctic National Park and Preserve, and the John River is a designated Wild River. Due to the concern about possible water-quality effects from the wastewater effluent, the hydrology of the John River near Anaktuvuk Pass was studied from 2002 through 2003. Three streams form the John River atAnaktuvuk Pass: Contact Creek, Giant Creek, and the John RiverTributary. These streams drain areas of 90.3 km (super 2) , 120 km (super 2) , and 4.6 km (super 2) , respectively. Water-qualitydata collected from these streams from 2002-03 indicate that the waters are a calcium-bicarbonate type and that Giant Creek adds a sulfate component to the John River. The highest concentrations of bicarbonate, calcium, sodium, sulfate, and nitrate were found at the John River Tributary below the wastewater-treatment lagoon. These concentrations have little effect on the water quality of the John River because the flow of the John River Tributary is only about 2 percent of the John River flow. To better understand the ground-water/surface-water interactions of the upper John River, a numerical groundwater-flow model of the headwater area of the John River was constructed. Processes that occur during spring break-up, such as thawing of the active layer and the frost table and the resulting changes of storage capacity of the aquifer, were difficult to measure and simulate. Application and accuracy of the model is limited by the lack of specific hydrogeologic data both spatially and temporally. However

  9. Hydrochemical assessments of surface Nile water and ground water in an industry area – South West Cairo

    Directory of Open Access Journals (Sweden)

    Mona El-Sayed

    2015-09-01

    The data obtained were used for mathematical calculations of some parameters such as sodium adsorption ratio (SAR, sodium percentage (Na%, and the suitability of water samples for drinking, domestic, and irrigation purposes was evaluated. The results indicate that most studied surface Nile water samples show excellent to good categories and are suitable for drinking and irrigation. Most studied ground water samples are not suitable for drinking and need treatment for irrigation; few samples are not suitable for any purpose because of pollution from different sources in this area.

  10. Different Multifractal Scaling of the 0 cm Average Ground Surface Temperature of Four Representative Weather Stations over China

    Directory of Open Access Journals (Sweden)

    Lei Jiang

    2013-01-01

    Full Text Available The temporal scaling properties of the daily 0 cm average ground surface temperature (AGST records obtained from four selected sites over China are investigated using multifractal detrended fluctuation analysis (MF-DFA method. Results show that the AGST records at all four locations exhibit strong persistence features and different scaling behaviors. The differences of the generalized Hurst exponents are very different for the AGST series of each site reflecting the different scaling behaviors of the fluctuation. Furthermore, the strengths of multifractal spectrum are different for different weather stations and indicate that the multifractal behaviors vary from station to station over China.

  11. Vibrational Spectra and Potential Energy Surface for Electronic Ground State of Jet-Cooled Molecule S2O

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Yan; DING Shi-Liang

    2004-01-01

    The vibration states of transition molecule S2O, including both bending and stretching vibrations, are studied in the framework of dynamical symmetry groups U1(4) U2(4). We get all the vibration spectra of S2O by fitting 22 spectra data with 10 parameters. The fitting rms of the Hamiltonian is 2.12 cm-1. With the parameters and Lie algebraic theory, we give the analytical expression of the potential energy surface, which helps us to calculate the dissociation energy and force constants of S2O in the electronic ground state.

  12. Elevation change of the Greenland ice sheet due to surface mass balance and firn processes, 1960-2013

    Science.gov (United States)

    Kuipers Munneke, P.; Ligtenberg, S. R. M.; Noël, B. P. Y.; Howat, I. M.; Box, J. E.; Mosley-Thompson, E.; McConnell, J. R.; Steffen, K.; Harper, J. T.; Das, S. B.; van den Broeke, M. R.

    2015-06-01

    Observed changes in the surface elevation of the Greenland ice sheet are caused by ice dynamics, basal elevation change, surface mass balance (SMB) variability, and by compaction of the overlying firn. The latter two contributions are quantified here using a firn model that includes compaction, meltwater percolation, and refreezing. The model is forced with surface mass fluxes and temperature from a regional climate model for the period 1960-2013. The model results agree with observations of surface density, density profiles from 62 firn cores, and altimetric observations from regions where ice-dynamical surface height changes are likely small. We find that the firn layer in the high interior is generally thickening slowly (1-5 cm yr-1). In the percolation and ablation areas, firn and SMB processes account for a surface elevation lowering of up to 20-50 cm yr-1. Most of this firn-induced marginal thinning is caused by an increase in melt since the mid-1990s, and partly compensated by an increase in the accumulation of fresh snow around most of the ice sheet. The total firn and ice volume change between 1980 and 2013 is estimated at -3900 ± 1030 km3 due to firn and SMB, corresponding to an ice-sheet average thinning of 2.32 ± 0.61 m. Most of this volume decrease occurred after 1995. The computed changes in surface elevation can be used to partition altimetrically observed volume change into surface mass balance and ice-dynamically related mass changes.

  13. Contamination of rural surface and ground water by endosulfan in farming areas of the Western Cape, South Africa

    Directory of Open Access Journals (Sweden)

    London Leslie

    2003-03-01

    Full Text Available Abstract Background In South Africa there is little data on environmental pollution of rural water sources by agrochemicals. Methods This study investigated pesticide contamination of ground and surface water in three intensive agricultural areas in the Western Cape: the Hex River Valley, Grabouw and Piketberg. Monitoring for endosulfan and chlorpyrifos at low levels was conducted as well as screening for other pesticides. Results The quantification limit for endosulfan was 0.1 μg/L. Endosulfan was found to be widespread in ground water, surface water and drinking water. The contamination was mostly at low levels, but regularly exceeded the European Drinking Water Standard of 0.1 μg/L. The two most contaminated sites were a sub-surface drain in the Hex River Valley and a dam in Grabouw, with 0.83 ± 1.0 μg/L (n = 21 and 3.16 ± 3.5 μg/L (n = 13 average endosulfan levels respectively. Other pesticides including chlorpyrifos, azinphos-methyl, fenarimol, iprodione, deltamethrin, penconazole and prothiofos were detected. Endosulfan was most frequently detected in Grabouw (69% followed by Hex River (46% and Piketberg (39%. Detections were more frequent in surface water (47% than in groundwater (32% and coincided with irrigation, and to a lesser extent, to spraying and trigger rains. Total dietary endosulfan intake calculated from levels found in drinking water did not exceed the Joint WHO/FAO Meeting on Pesticide Residues (JMPR criteria. Conclusion The study has shown the need for monitoring of pesticide contamination in surface and groundwater, and the development of drinking water quality standards for specific pesticides in South Africa.

  14. Bacteriophages reduce experimental contamination of hard surfaces, tomato, spinach, broccoli, and ground beef by Escherichia coli O157:H7.

    Science.gov (United States)

    Abuladze, Tamar; Li, Manrong; Menetrez, Marc Y; Dean, Timothy; Senecal, Andre; Sulakvelidze, Alexander

    2008-10-01

    A bacteriophage cocktail (designated ECP-100) containing three Myoviridae phages lytic for Escherichia coli O157:H7 was examined for its ability to reduce experimental contamination of hard surfaces (glass coverslips and gypsum boards), tomato, spinach, broccoli, and ground beef by three virulent strains of the bacterium. The hard surfaces and foods contaminated by a mixture of three E. coli O157:H7 strains were treated with ECP-100 (test samples) or sterile phosphate-buffered saline buffer (control samples), and the efficacy of phage treatment was evaluated by comparing the number of viable E. coli organisms recovered from the test and control samples. Treatments (5 min) with the ECP-100 preparation containing three different concentrations of phages (10(10), 10(9), and 10(8) PFU/ml) resulted in statistically significant reductions (P = E. coli O157:H7 organisms recovered from the glass coverslips. Similar treatments resulted in reductions of 100%, 95%, and 85%, respectively, in the number of E. coli O157:H7 organisms recovered from the gypsum board surfaces; the reductions caused by the two most concentrated phage preparations were statistically significant. Treatment with the least concentrated preparation that elicited significantly less contamination of the hard surfaces (i.e., 10(9) PFU/ml) also significantly reduced the number of viable E. coli O157:H7 organisms on the four food samples. The observed reductions ranged from 94% (at 120 +/- 4 h posttreatment of tomato samples) to 100% (at 24 +/- 4 h posttreatment of spinach samples). The data suggest that naturally occurring bacteriophages may be useful for reducing contamination of various hard surfaces, fruits, vegetables, and ground beef by E. coli O157:H7.

  15. ENVIRONMENTAL SAFETY IMPROVEMENT OF SURFACE AND GROUND WATER CONTAMINATION AT THE AIRPORT AREA

    Directory of Open Access Journals (Sweden)

    Svitlana Madzhd

    2016-11-01

    Full Text Available Purpose: Taking into account that the airport "Kyiv" is located in one of the central districts of Kyiv and does not have clearly established sanitary protection zones, the problem of environmental pollution is topical and requires monitoring and research. In order to improve environmental compliance we made assessment of superficial and ground water quality in airport zone. Methods: Water quality was estimated by the biotesting method, hydrochemical analysis, and by oil products detection method. Results We performed analysis of wastewaters of airport “Kyiv” and superficial waters of river Nyvka. The samples took place: above the airport drainage, in the drainage place and below drainage place. We conducted assessment of ground waters, which are sources of water supply, on different distance from an airport (20 m, 500 m, 1000 m, 1500 min. Results of hydrochemical investigations of river indicated excess of nitrogen compounds content compare to regulatory discharge. Thus, it was defined excess of ammonia nitrogen in wastewaters in three times and in place of dispersion – in ten times; the content of nitrite nitrogen in the river sample after discharge exceeds in 22 times norm. Analysis of drinking water in airport zone has showed extremely high level of pollution by nitrite nitrogen exceeding norm in 7-17 times. After analysis it was defined high level of river pollution by oil products (in 26-32 times higher than MPC, and ground water in 1, 5-2 times. Results of biotesting confirmed data of hydrochemical investigations of superficial water state (acute toxicity was observed in drainage area and in place of drainage dispersion. Discussion: Increased content of nitrite indicates the strengthening of decomposition process of organic matter in conditions of slower oxidation of NO into NO. This parameter is major sanitary indicator which indicates pollution of water body. High content of such specific pollutant for aviation transport

  16. Influence of the underlying surface on the antenna system of the ground penetrating radar

    Science.gov (United States)

    Balzovsky, E. V.; Buyanov, Yu I.; Shipilov, S. E.

    2017-08-01

    Simulation results of the antenna system of the radar of subsurface sounding intended for contactless investigation of the road condition are presented. The elements of the antenna system of ground penetrating radar with extended bandwidth made as a combination of electric and magnetic type radiators have been designed. The transmission coefficient between the elements of the antenna array determining their mutual influence has been calculated. Despite the close arrangement of the elements in the array, the level of mutual influence of the elements is not critical. The developed antenna array can be used both for excitation with short ultrawideband pulses and for frequency steering in the range of 0.8-4 GHz.

  17. Assessment of volatile organic compounds in surface water at Canal Creek, Aberdeen Proving Ground, Maryland, November 1999-September 2000

    Science.gov (United States)

    Phelan, Daniel J.; Olsen, Lisa D.; Senus, Michael P.; Spencer, Tracey A.

    2001-01-01

    The purpose of this report is to describe the occurrence and distribution of volatile organic compounds in surface-water samples collected by the U.S. Geological Survey in the Canal Creek area of Aberdeen Proving Ground, Maryland, from November 1999 through September 2000. The report describes the differences between years with below normal and normal precipitation, the effects of seasons, tide stages, and location on volatile organic compound concentrations in surface water, and provides estimates of volatile organic concentration loads to the tidal Gunpowder River. Eighty-four environmental samples from 20 surface-water sites were analyzed. As many as 13 different volatile organic compounds were detected in the samples. Concentrations of volatile organic compounds in surface-water samples ranged from below the reporting limit of 0.5 micrograms per liter to a maximum of 50.2 micrograms per liter for chloroform. Chloroform was detected most frequently, and was found in 55 percent of the environmental samples that were analyzed for volatile organic compounds (46 of 84 samples). Carbon tetrachloride was detected in 56 percent of the surface-water samples in the tidal part of the creek (34 of 61 samples), but was only detected in 3 of 23 samples in the nontidal part of the creek. 1,1,2,2-Tetrachloroethane was detected in 43 percent of the tidal samples (26 of 61 samples), but was detected at only two nontidal sites and only during November 1999. Three samples were collected from the tidal Gunpowder River about 300 feet from the mouth of Canal Creek in May 2000, and none of the samples contained volatile organic compound concentrations above detection levels. Volatile organic compound concentrations in surface water were highest in the reaches of the creek adjacent to the areas with the highest known levels of ground-water contamination. The load of total volatile organic compounds from Canal Creek to the Gunpowder River is approximately 1.85 pounds per day (0

  18. Road impacts on the Baca National Wildlife Refuge, Colorado, with emphasis on effects to surface and shallow ground-water hydrology : a literature review

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A review of published research on unpaved road effects on surface-water and shallow ground-water hydrology was undertaken to assist the Baca National Wildlife...

  19. Estimated potentiometric surface by D'Agnese and others (1998), for the Death Valley regional ground-water flow system study, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — D'Agnese and others (1998) developed a potentiometric surface to conceptualize the regional ground-water flow system and to construct numerical flow models of the...

  20. AATSR Land Surface Temperature Product Validation Using Ground Measurements in China and Implications for SLSTR

    Science.gov (United States)

    Zhou, Ji; Zmuda, Andy; Desnos, Yves-Louis; Ma, Jin

    2016-08-01

    Land surface temperature (LST) is one of the most important parameters at the interface between the earth's surface and the atmosphere. It acts as a sensitive indicator of climate change and is an essential input parameter for land surface models. Because of the intense variability at different spatial and temporal scales, satellite remote sensing provides the sole opportunity to acquire LSTs over large regions. Validation of the LST products is an necessary step before their applications conducted by scientific community and it is essential for the developers to improve the LST products.

  1. 3D simulation of near-fault strong ground motion:comparison between surface rupture fault and buried fault

    Institute of Scientific and Technical Information of China (English)

    Liu Qifang; Yuan Yifan; Jin Xing

    2007-01-01

    In this paper,near-fault strong ground motions caused by a surface rupture fault(SRF)and a buried fault(BF) are numerically simulated and compared by using a time-space-decoupled,explicit finite element method combined with a multi-transmitting formula(MTF) of an artificial boundary.Prior to the comparison,verification of the explicit element method and the MTF is conducted.The comparison results show that the final dislocation of the SRF is larger than the BF for the same stress drop on the fault plane.The maximum final dislocation occurs on the fault upper line for the SRF;however,for the BF,the maximum final dislocation is located on the fault central part.Meanwhile,the PGA,PGV and PGD of long period ground motions(≤1 Hz)generated by the SRF are much higher than those of the BF in the near-fault region.The peak value of the velocity pulse generated by the SRF is also higher than the BF.Furthermore,it is found that in a very narrow region along the fault trace,ground motions caused by the SRF are much higher than by the BF.These results may explain why SRFs almost always cause heavy damage in near-fault regions compared to buried faults.

  2. Activities of the Commission for Ground Surface Protection against Mining Damage in the first quarter of 1985. [Poland

    Energy Technology Data Exchange (ETDEWEB)

    Chroszcz, A.

    1985-01-01

    Five meetings of the Commission held from January to March 1985 are reported. Underground coal mining in the safety pillar of Bytom was discussed in the light of rock bursts and fatal accidents in the Dymitrow mine. Three coal mines remove the safety pillar: Dymitrow, Szombierki and Rozbark. The Commission discussed: replacing longwall mining with caving by longwall mining with hydraulic stowing, using packings with reduced settling, reducing concentration of mining operations in the area of Bytom center, coordination of underground mining by 3 mines (coordination of mining order, thickness of coal slices or coal seams, concentration of longwall mining in seams with reduced hazards of rock bursts, methods for protection of buildings and industrial plants at the ground surface against ground deformation. The Commission also discussed program of coal mining with hydraulic stowing in the safety pillar of the Batory Steelworks, the Hajduki chemical plant and Chorzow (order of mining, schemes for slice mining, forecasting ground subsidence, methods for protection against mining damage), underground mining with caving or stowing in safety pillars of the Miechowice and Karb mines under Bytom, new regulations on geodetic surveys in underground coal mines.

  3. Environmental impact of highway construction and repair materials on surface and ground waters. Case study: crumb rubber asphalt concrete.

    Science.gov (United States)

    Azizian, Mohammad F; Nelson, Peter O; Thayumanavan, Pugazhendhi; Williamson, Kenneth J

    2003-01-01

    The practice of incorporating certain waste products into highway construction and repair materials (CRMs) has become more popular. These practices have prompted the National Academy of Science, National Cooperative Highway Research Program (NCHRP) to research the possible impacts of these CRMs on the quality of surface and ground waters. State department of transportations (DOTs) are currently experimenting with use of ground tire rubber ( crumb rubber) in bituminous construction and as a crack sealer. Crumb rubber asphalt concrete (CR-AC) leachates contain a mixture of organic and metallic contaminants. Benzothiazole and 2(3H)-benzothiazolone (organic compounds used in tire rubber manufacturing) and the metals mercury and aluminum were leached in potentially harmful concentrations (exceeding toxic concentrations for aquatic toxicity tests). CR-AC leachate exhibited moderate to high toxicity for algae ( Selenastrum capriconutum) and moderate toxicity for water fleas ( Daphnia magna). Benzothiazole was readily removed from CR-AC leachate by the environmental processes of soil sorption, volatilization, and biodegradation. Metals, which do not volatilize or photochemically or biologically degrade, were removed from the leachate by soil sorption. Contaminants from CR-AC leachates are thus degraded or retarded in their transport through nearby soils and ground waters.

  4. Determination of barium in surface and ground waters at Centro Experimental Aramar area

    Energy Technology Data Exchange (ETDEWEB)

    Matoso, Erika, E-mail: ematoso@hotmail.com [Centro Tecnologico da Marinha em Sao Paulo (CEA/CTMS), Ipero, SP (Brazil). Centro Experimental Aramar; Cadore, Solange, E-mail: cadore@iqm.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Quimica. Departamento de Quimica Analica

    2015-07-01

    Barium can be found in waters up to 1 mg L{sup -1} and came from natural sources such as sedimentary rocks erosion rich in feldspar and barite. Also anthropogenic activities can release this element such as oil and gas industry, agricultural defensives, chemical industry and waste disposal. At high doses, barium can be harmful to human central nervous system and can also cause high blood pressure, heart problems, fatigue and anxiety. The water potability defined by Brazilian's Ministry of Healthy sets barium concentration up to 0.7 mg L{sup -1} and official regulation defines the same limit of this element to superficial waters (according CONAMA resolution 357/2005) and ground waters (Sao Paulo state regulation). In this work, barium was analyzed monthly in superficial waters from 4 different sampling locations, located in a ratio of 10-km-long from Centro Experimental Aramar (CEA) at Ipanema River, during one year, in order to evaluate the river in different conditions (seasons, temperature and rain period). The ground water was collected every six months. The analytical technique applied was ICP OES and the method conditions were optimized: wavelength, linearity, signal background ratio, detection and quantification limits. Data obtained in this work will contribute to evaluate the presence of barium at CEA region and nearby in order to compare it with current Brazilian regulations. (author)

  5. Tracing nitrate pollution sources and transformation in surface- and ground-waters using environmental isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan [Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Fadong, E-mail: lifadong@igsnrr.ac.cn [Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Zhang, Qiuying [Center for Agricultural Resources Research, Chinese Academy of Sciences, Shijiazhuang 050021 (China); Li, Jing [Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Liu, Qiang [Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

    2014-08-15

    Water pollution in the form of nitrate nitrogen (NO{sub 3}{sup −}–N) contamination is a major concern in most agricultural areas in the world. Concentrations and nitrogen and oxygen isotopic compositions of nitrate, as well as oxygen and deuterium isotopic compositions of surface and groundwater from a typical irrigated region in the North China Plain (NCP) collected from May to October in 2012 were analyzed to examine the major nitrate sources and transformations. Concentrations of NO{sub 3}{sup −}–N ranged from 0.2 to 29.6 mg/L (mean of 11.2 mg/L) in surface water, and from 0.1 to 19.4 mg/L (mean of 2.8 mg/L) in groundwater. Approximately 46.7% of the surface water samples and 10% of the groundwater samples exceeded the World Health Organization (WHO) drinking water standard for NO{sub 3}{sup −}–N. Surface water samples that exceeded the standard were collected mainly in the dry season (May and October), while groundwater samples that exceeded the standard were collected in the wet season (June). Overall, the highest nitrate levels were observed in surface water in May and in groundwater in June, indicating that fertilizer application, precipitation, and irrigation strongly influence the NO{sub 3}{sup −}–N concentrations. Analyses of isotopic compositions suggest that the main sources of nitrate are nitrification of fertilizer and sewage in surface water, in contrast, mineralization of soil organic N and sewage is the groundwater sources during the dry season. When fertilizers are applied, nitrate will be transported by precipitation through the soil layers to the groundwater in the wet season (June). Denitrification only occurred in surface water in the wet season. Attempts should be made to minimize overuse of nitrogen fertilizers and to improve nitrogen use efficiency in irrigated agricultural regions. - Highlights: • Nitrate sources in surface and groundwater were identified by multiple isotopes. • Nitrate pollution displayed obvious

  6. Be(1010): A test ground for surface electron-phonon coupling

    Science.gov (United States)

    Tang, Shu-Jung; Sprunger, Philip; Plummer, Ward; Yang, Wanli; Brouet, Veronique; Zhou, Xingjiang; Shen, Zhi-Xun

    2003-03-01

    The electron-phonon coupling on the Be(10bar10) surface has been investigated with high-resolution photoemission examining temperature dependence and dispersion distortion near the Fermi energy of the two zone boundary surface states. Two surface states (S1 and S2) coexist in a large gap in the bulk projection at the surface zone boundary barA. S1 is localized near the surface in the middle of the gap while S2 is near the bottom band edge and penetrates into the bulk. Using both a Debye and Einstein model to fit the temperature-dependent surface state line width produces an electron-phonon coupling strength with parameters, λ _S1 = 0.647 and λ _S2 = 0.491, more than two times larger than the bulk value, λ _bulk = 0.24. S2 data was measured with a 3D Debye model but the S1 data required an Einstein model with an optical phonon at energy 64 meV. Direct 2D images of the dispersion of the S1 state show dramatic distortion of the electron band dispersion within 64 meV of the Fermi energy. This data is used to extract the real and imaginary parts of the self-energy. Founded by NSF DMR-0105232 and Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Dept. of Energy under contract DE-AC05-00OR22725

  7. High resolution surface solar radiation patterns over Eastern Mediterranean: Satellite, ground-based, reanalysis data and radiative transfer simulations

    Science.gov (United States)

    Alexandri, G.; Georgoulias, A.; Meleti, C.; Balis, D.

    2013-12-01

    Surface solar radiation (SSR) and its long and short term variations play a critical role in the modification of climate and by extent of the social and financial life of humans. Thus, SSR measurements are of primary importance. SSR is measured for decades from ground-based stations for specific spots around the planet. During the last decades, satellite observations allowed for the assessment of the spatial variability of SSR at a global as well as regional scale. In this study, a detailed spatiotemporal view of the SSR over Eastern Mediterranean is presented at a high spatial resolution. Eastern Mediterranean is affected by various aerosol types (continental, sea, dust and biomass burning particles) and encloses countries with significant socioeconomical changes during the last decades. For the aims of this study, SSR data from satellites (Climate Monitoring Satellite Application Facility - CM SAF) and our ground station in Thessaloniki, a coastal city of ~1 million inhabitants in northern Greece, situated in the heart of Eastern Mediterranean (Eppley Precision pyranometer and Kipp & Zonen CM-11 pyranometer) are used in conjunction with radiative transfer simulations (Santa Barbara DISORT Atmospheric Radiative Transfer - SBDART). The CM SAF dataset used here includes monthly mean SSR observations at a high spatial resolution of 0.03x0.03 degrees for the period 1983-2005. Our ground-based SSR observations span from 1983 until today. SBDART radiative transfer simulations were implemented for a number of spots in the area of study in order to calculate the SSR. High resolution (level-2) aerosol and cloud data from MODIS TERRA and AQUA satellite sensors were used as input, as well as ground-based data from the AERONET. Data from other satellites (Earth Probe TOMS, OMI, etc) and reanalysis projects (ECMWF) were used where needed. The satellite observations, the ground-based measurements and the model estimates are validated against each other. The good agreement

  8. Simultaneous Retrieval of Aerosol and Surface Optical Properties from Combined Airborne- and Ground-Based Direct and Diffuse Radiometric Measurements

    Science.gov (United States)

    Gatebe, C. K.; Dubovik, O.; King, M. D.; Sinyuk, A.

    2010-01-01

    This paper presents a new method for simultaneously retrieving aerosol and surface reflectance properties from combined airborne and ground-based direct and diffuse radiometric measurements. The method is based on the standard Aerosol Robotic Network (AERONET) method for retrieving aerosol size distribution, complex index of refraction, and single scattering albedo, but modified to retrieve aerosol properties in two layers, below and above the aircraft, and parameters on surface optical properties from combined datasets (Cloud Absorption Radiometer (CAR) and AERONET data). A key advantage of this method is the inversion of all available spectral and angular data at the same time, while accounting for the influence of noise in the inversion procedure using statistical optimization. The wide spectral (0.34-2.30 m) and angular range (180 ) of the CAR instrument, combined with observations from an AERONET sunphotometer, provide sufficient measurement constraints for characterizing aerosol and surface properties with minimal assumptions. The robustness of the method was tested on observations made during four different field campaigns: (a) the Southern African Regional Science Initiative 2000 over Mongu, Zambia, (b) the Intercontinental Transport Experiment-Phase B over Mexico City, Mexico (c) Cloud and Land Surface Interaction Campaign over the Atmospheric Radiation Measurement (ARM) Central Facility, Oklahoma, USA, and (d) the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) over Elson Lagoon in Barrow, Alaska, USA. The four areas are dominated by different surface characteristics and aerosol types, and therefore provide good test cases for the new inversion method.

  9. Areal-Averaged Spectral Surface Albedo from Ground-Based Transmission Data Alone: Toward an Operational Retrieval

    Directory of Open Access Journals (Sweden)

    Evgueni Kassianov

    2014-08-01

    Full Text Available We present here a simple retrieval of the areal-averaged spectral surface albedo using only ground-based measurements of atmospheric transmission under fully overcast conditions. Our retrieval is based on a one-line equation. The feasibility of our retrieval for routine determinations of albedo is demonstrated for different landscapes with various degrees of heterogeneity using three sets of measurements: (1 spectral atmospheric transmission from the Multi-Filter Rotating Shadowband Radiometer (MFRSR at five wavelengths (415, 500, 615, 673, and 870 nm; (2 tower-based measurements of local surface albedo at the same wavelengths; and (3 areal-averaged surface albedo at four wavelengths (470, 560, 670 and 860 nm from collocated and coincident Moderate Resolution Imaging Spectroradiometer (MODIS observations. These integrated datasets cover both temporally long (2008–2013 and short (April–May 2010 periods at the Atmospheric Radiation Measurement (ARM Southern Great Plains site and the National Oceanic and Atmospheric Administration (NOAA Table Mountain site, respectively. The calculated root mean square error (RMSE, defined here as the root mean squared difference between the MODIS-derived surface albedo and the retrieved areal-averaged albedo, is quite small (RMSE ≤ 0.015 and comparable with that obtained previously by other investigators for the shortwave broadband albedo. Good agreement between tower-based measurements of daily-averaged surface albedo for completely overcast and non-overcast conditions is also demonstrated.

  10. Survival of adenovirus types 2 and 41 in surface and ground waters measured by a plaque assay.

    Science.gov (United States)

    Rigotto, C; Hanley, K; Rochelle, P A; De Leon, R; Barardi, C R M; Yates, M V

    2011-05-01

    To manage artificial recharge systems, it is necessary to understand the inactivation process of microorganisms within aquifers so that requirements regarding storage times and treatment strategies for ground and surface waters can be developed and modeled to improve water management practices. This study was designed to investigate the survival of representative adenoviruses in surface- and groundwaters using a cell culture plaque assay with human lung carcinoma cells (A549) to enumerate surviving viruses. Adenovirus types 2 (Ad2) and 41 (Ad41) were seeded into 50 mL of three sterilized surface waters and groundwaters, and incubated at 10 and 19 °C for up to 301 days. Concentrations of Ad2 and Ad41 were relatively stable in all waters at 10 °C for at least 160 days and in some instances up to 301 days. At 19 °C, virus concentrations were reduced by 99.99% (4 log) after 301 days in surface water. There was approximately 90% (1 log) reduction of both viruses at 19 °C after 160 days of incubation in groundwater samples. There was no overall difference in survival kinetics in surface waters compared to groundwaters. The relatively high stability and long-term survival of adenoviruses in environmental waters at elevated temperatures should be considered in risk assessment models and drinking water management strategies.

  11. Evaluating the effects of urbanization and land-use planning using ground-water and surface-water models

    Science.gov (United States)

    Hunt, R.J.; Steuer, J.J.

    2001-01-01

    Why are the effects of urbanization a concern? As the city of Middleton, Wisconsin, and its surroundings continue to develop, the Pheasant Branch watershed (fig.l) is expected to undergo urbanization. For the downstream city of Middleton, urbanization in the watershed can mean increased flood peaks, water volume and pollutant loads. More subtly, it may also reduce water that sustains the ground-water system (called "recharge") and adversely affect downstream ecosystems that depend on ground water such as the Pheasant Branch Springs (hereafter referred to as the Springs). The relation of stormwater runoff and reduced ground-water recharge is complex because the surface-water system is coupled to the underlying ground-water system. In many cases there is movement of water from one system to the other that varies seasonally or daily depending on changing conditions. Therefore, it is difficult to reliably determine the effects of urbanization on stream baseflow and spring flows without rigorous investigation. Moreover, mitigating adverse effects after development has occurred can be expensive and administratively difficult. Overlying these concerns are issues such as stewardship of the resource, the rights of the public, and land owners' rights both of those developing their land and those whose land is affected by this development. With the often- contradictory goals, a scientific basis for assessing effects of urbanization and effectiveness of mitigation measures helps ensure fair and constructive decision-making. The U.S. Geological Survey, in cooperation with the City of Middleton and Wisconsin Department of Natural Resources, completed a study that helps address these issues through modeling of the hydrologic system. This Fact Sheet discusses the results of this work.

  12. Monitoring ground-surface heating during expansion of the Casa Diablo production well field at Mammoth Lakes, California

    Science.gov (United States)

    Bergfeld, D.; Vaughan, R. Greg; Evans, William C.; Olsen, Eric

    2015-01-01

    The Long Valley hydrothermal system supports geothermal power production from 3 binary plants (Casa Diablo) near the town of Mammoth Lakes, California. Development and growth of thermal ground at sites west of Casa Diablo have created concerns over planned expansion of a new well field and the associated increases in geothermal fluid production. To ensure that all areas of ground heating are identified prior to new geothermal development, we obtained high-resolution aerial thermal infrared imagery across the region. The imagery covers the existing and proposed well fields and part of the town of Mammoth Lakes. Imagery results from a predawn flight on Oct. 9, 2014 readily identified the Shady Rest thermal area (SRST), one of two large areas of ground heating west of Casa Diablo, as well as other known thermal areas smaller in size. Maximum surface temperatures at 3 thermal areas were 26–28 °C. Numerous small areas with ground temperatures >16 °C were also identified and slated for field investigations in summer 2015. Some thermal anomalies in the town of Mammoth Lakes clearly reflect human activity.Previously established projects to monitor impacts from geothermal power production include yearly surveys of soil temperatures and diffuse CO2 emissions at SRST, and less regular surveys to collect samples from fumaroles and gas vents across the region. Soil temperatures at 20 cm depth at SRST are well correlated with diffuse CO2 flux, and both parameters show little variation during the 2011–14 field surveys. Maximum temperatures were between 55–67 °C and associated CO2 discharge was around 12–18 tonnes per day. The carbon isotope composition of CO2 is fairly uniform across the area ranging between –3.7 to –4.4 ‰. The gas composition of the Shady Rest fumarole however has varied with time, and H2S concentrations in the gas have been increasing since 2009.

  13. An Approach for Predicting the Shape and Size of a Buried Basic Object on Surface Ground Penetrating Radar System

    Directory of Open Access Journals (Sweden)

    Nana Rachmana Syambas

    2012-01-01

    Full Text Available Surface ground-penetrating radar (GPR is one of the radar technology that is widely used in many applications. It is nondestructive remote sensing method to detect underground buried objects. However, the output target is only hyperbolic representation. This research develops a system to identify a buried object on surface GPR based on decision tree method. GPR data of many basic objects (with circular, triangular, and rectangular cross-section are classified and extracted to generate data training model as a unique template for each type of basic object. The pattern of object under test will be known by comparing its data with the training data using a decision tree method. A simple powerful algorithm to extract feature parameters of object which is based on linear extrapolation is proposed. The result showed that tested buried basic objects can be correctly predicted and the developed system works properly.

  14. A semiempirical study of the optimized ground and excited state potential energy surfaces of retinal and its protonated Schiff base

    Science.gov (United States)

    Parusel, A. B.; Pohorille, A.

    2001-01-01

    The electronic ground and first excited states of retinal and its Schiff base are optimized for the first time using the semiempirical AM1 Hamiltonian. The barrier for rotation about the C(11)-C(12) double bond is characterized by variation of both the twist angle delta(C(10)-C(11)-C(12)-C(13)) and the bond length d(C(11)-C(12)). The potential energy surface is obtained by varying these two parameters. The calculated ground state rotational barrier is equal to 15.6 kcal/mol for retinal and 20.5 kcal/mol for its Schiff base. The all-trans conformation is more stable by 3.7 kcal/mol than the 11-cis geometry. For the first excited state, S(1,) the 90 degrees twisted geometry represents a saddle point for retinal with the rotational barrier of 14.6 kcal/mol. In contrast, this conformation is an energy minimum for the Schiff base. It can be easily reached at room temperature from the planar minima since it is separated from them by a barrier of only 0.6 kcal/mol. The 90 degrees minimum conformation is more stable than the all-trans by 8.6 kcal/mol. We are thus able to present a reaction path on the S(1) surface of the retinal Schiff base with an almost barrier-less geometrical relaxation into a twisted minimum geometry, as observed experimentally. The character of the ground and first excited singlet states underscores the need for the inclusion of double excitations in the calculations.

  15. Estimating Saturated Hydraulic Conductivity from Surface Ground-Penetrating Radar Monitoring of Infiltration

    CERN Document Server

    Léger, Emmanuel; Coquet, Yves

    2013-01-01

    In this study we used Hydrus-1D to simulate water infiltration from a ring infiltrometer. We generated water content profiles at each time step of infiltration, based on a particular value of the saturated hydraulic conductivity while knowing the other van Genuchten parameters. Water content profiles were converted to dielectric permittivity profiles using the Complex Refractive Index Method relation. We then used the GprMax suite of programs to generate radargrams and to follow the wetting front using arrival time of electromagnetic waves recorded by a Ground-Penetrating Radar (GPR). Theoretically, the depth of the inflection point of the water content profile simulated at any infiltration time step is related to the peak of the reflected amplitude recorded in the corresponding trace in the radargram. We used this relationship to invert the saturated hydraulic conductivity for constant and falling head infiltrations. We present our method on synthetic examples and on two experiments carried out on sand. We f...

  16. STUDY OF PHYSICO-CHEMICAL PROPERTIES OF THE SURFACE AND GROUND WATER

    Directory of Open Access Journals (Sweden)

    A. Y. Al-Ghamdi

    2014-01-01

    Full Text Available Of all the natural resources, water is unarguably the most essential and precious. Life began in water and life is nurtured by water. Ninety seven percent of the world’s water is found in oceans. Only 2.5% of the world’s water are non-saline fresh water. Saudi Arabia is a desert country with no permanent rivers or lakes and very little rainfall. Water is scarce and extremely valuable and with the country’s rapid growth, the demand for water is increasing. Seven samples of water are collected, six samples from Wells (1-6 and the last sample from Al-Mallah Valley Dam, Mukhwa (7, Al-Mukhwah, in order to find impurities and pollutants and found some suitable solution. Some physical properties of water are measured such as turbidity, conductivity, pH and also, some pollutants such as iron, manganese, nitrate, nitrite fluoride, phosphate as well as calcium, magnesium, sulfate and chloride as well as detection of some microorganisms. The results shown that, the water of Al-Mallah Valley Dam has a high percentage of turbidity as a result of contamination of water with clay, plant residues and also some dead animals. On the other hand, the samples of ground water have high conductivity and high value of fluoride, nitrite, nitrate contents as well as Mn and Fe. Also the result of microorganisms showed the presence of some the water of Al-Mallah Valley Dam can be treated with a very simple method and become suitable for drinking. Also ground water can be treated with a suitable method to reduce the total hardness and some pollutants. But its content of fluoride is higher than that of gulf specifications so it must be treated before used.

  17. Characterizing Geothermal Surface Manifestation Based on Multivariate Geostatistics of Ground Measurements Data

    Science.gov (United States)

    Ishaq; Nur Heriawan, Mohamad; Saepuloh, Asep

    2016-09-01

    Mt. Wayang Windu is one of geothermal field located in West Java, Indonesia. The characterization of steam spots at surface manifestation zones based on the soil physical measurements of the area is presented in this study. The multivariate geostatistical methods incorporating the soil physical parameter data were used to characterize the zonation of geothermal surface manifestations. The purpose of this study is to evaluate the performance of spatial estimation method of multivariate geostatistics using Ordinary Cokriging (COK) to characterize the physical properties of geothermal surface manifestations at Mt. Wayang Windu. The COK method was selected because this method is favorable when the secondary variables has more number than the primary variables. There are four soil physical parameters used as the basis of COK method, i.e. Electrical Conductivity, Susceptibility, pH, and Temperature. The parameters were measured directly at and around geothermal surface manifestations including hot springs, fumaroles, and craters. Each location of surface manifestations was measured about 30 points with 30 x 30 m grids. The measurement results were analyzed by descriptive statistics to identify at the nature of data. The correlation among variables was analyzed using linear regression. When the correlation coefficient among variables is higher, the estimation results is expected to have better Linear Coregionalization Model (LCM). LCM was used to analyze the spatial correlation of each variable based on their variogram and cross-variogram model. In oder to evaluate the performance of multivariate geostatistical using COK method, a Root Mean Square Error (RMSE) was performed. Estimation result using COK method is well applicable for characterizing the surface physics parameters of radar images data.

  18. Quality-control results for ground-water and surface-water data, Sacramento River Basin, California, National Water-Quality Assessment, 1996-1998

    Science.gov (United States)

    Munday, Cathy; Domagalski, Joseph L.

    2003-01-01

    Evaluating the extent that bias and variability affect the interpretation of ground- and surface-water data is necessary to meet the objectives of the National Water-Quality Assessment (NAWQA) Program. Quality-control samples used to evaluate the bias and variability include annual equipment blanks, field blanks, field matrix spikes, surrogates, and replicates. This report contains quality-control results for the constituents critical to the ground- and surface-water components of the Sacramento River Basin study unit of the NAWQA Program. A critical constituent is one that was detected frequently (more than 50 percent of the time in blank samples), was detected at amounts exceeding water-quality standards or goals, or was important for the interpretation of water-quality data. Quality-control samples were collected along with ground- and surface-water samples during the high intensity phase (cycle 1) of the Sacramento River Basin NAWQA beginning early in 1996 and ending in 1998. Ground-water field blanks indicated contamination of varying levels of significance when compared with concentrations detected in environmental ground-water samples for ammonia, dissolved organic carbon, aluminum, and copper. Concentrations of aluminum in surface-water field blanks were significant when compared with environmental samples. Field blank samples collected for pesticide and volatile organic compound analyses revealed no contamination in either ground- or surface-water samples that would effect the interpretation of environmental data, with the possible exception of the volatile organic compound trichloromethane (chloroform) in ground water. Replicate samples for ground water and surface water indicate that variability resulting from sample collection, processing, and analysis was generally low. Some of the larger maximum relative percentage differences calculated for replicate samples occurred between samples having lowest absolute concentration differences and(or) values near

  19. Regional subsidence modelling in Murcia city (SE Spain using 1-D vertical finite element analysis and 2-D interpolation of ground surface displacements

    Directory of Open Access Journals (Sweden)

    S. Tessitore

    2015-11-01

    Full Text Available Subsidence is a hazard that may have natural or anthropogenic origin causing important economic losses. The area of Murcia city (SE Spain has been affected by subsidence due to groundwater overexploitation since the year 1992. The main observed historical piezometric level declines occurred in the periods 1982–1984, 1992–1995 and 2004–2008 and showed a close correlation with the temporal evolution of ground displacements. Since 2008, the pressure recovery in the aquifer has led to an uplift of the ground surface that has been detected by the extensometers. In the present work an elastic hydro-mechanical finite element code has been used to compute the subsidence time series for 24 geotechnical boreholes, prescribing the measured groundwater table evolution. The achieved results have been compared with the displacements estimated through an advanced DInSAR technique and measured by the extensometers. These spatio-temporal comparisons have showed that, in spite of the limited geomechanical data available, the model has turned out to satisfactorily reproduce the subsidence phenomenon affecting Murcia City. The model will allow the prediction of future induced deformations and the consequences of any piezometric level variation in the study area.

  20. Ab initio ground state phenylacetylene-argon intermolecular potential energy surface and rovibrational spectrum

    DEFF Research Database (Denmark)

    Cybulski, Hubert; Fernandez, Berta; Henriksen, Christian

    2012-01-01

    We evaluate the phenylacetylene-argon intermolecular potential energy surface by fitting a representative number of ab initio interaction energies to an analytic function. These energies are calculated at a grid of intermolecular geometries, using the CCSD(T) method and the aug-cc-pVDZ basis set ...

  1. Expanding surfaces: The viewer immersed in multiple modes of representation Following the drawing on the ground

    DEFF Research Database (Denmark)

    Carbone, Claudia

    2015-01-01

    The experience of the exhibition On the Surface – a retrospective of the work of Metis, the Edinburgh-based atelier of Mark Dorrian and Adrian Hawker, presented in the exhibition space of The Aarhus School of Architecture – is choreographed as a walk over superimposed fragments of architectural...

  2. A simple model for the assessment of indoor radionuclide Pb-210 surface contamination due to the presence of radon

    Directory of Open Access Journals (Sweden)

    Mrđa Dušan S.

    2013-01-01

    Full Text Available The presented, very simplified model provides a possibility for estimation of surface Pb-210 activity, depending on the changes of Rn-222 concentration during the long-term radon presence inside the closed room. This can be useful for retrospective assessment of the average indoor radon concentration for certain historical period, based on the surface contamination by the radionuclide Pb-210 in a closed or poorly ventilated room over a long period of time. However, the surface Pb-210 contamination depends on the pattern of radon concentration changes, and in this model is supposed that the change of indoor radon concentration, which periodically enters the room, is affected only by the radioactive decay and the inserted amount of radon in each entry. So, each radon entry can be comprehended as a “net amount” of radon, or excess which remains inside the room due to radon’s periodical in-out flow. It is shown, that under the conditions of the model, the achieved average value of radon concentration of 275 Bq/m3, implies that the saturated surface contamination by the Pb-210 of 160 Bq/m2 after approximately 150 years. [Projekat Ministarstva nauke Republike Srbije, br. 171002: Nuclear Methods Investigations of Rare Processes and Cosmic Rays i br. 43002: Biosensing Technologies and Global System for Continuous Research and Integrated Management of ecosystems

  3. Hydrology, Water Quality, and Surface- and Ground-Water Interactions in the Upper Hillsborough River Watershed, West-Central Florida

    Science.gov (United States)

    Trommer, J.T.; Sacks, L.A.; Kuniansky, E.L.

    2007-01-01

    A study of the Hillsborough River watershed was conducted between October 1999 through September 2003 to characterize the hydrology, water quality, and interaction between the surface and ground water in the highly karstic uppermost part of the watershed. Information such as locations of ground-water recharge and discharge, depth of the flow system interacting with the stream, and water quality in the watershed can aid in prudent water-management decisions. The upper Hillsborough River watershed covers a 220-square-mile area upstream from Hillsborough River State Park where the watershed is relatively undeveloped. The watershed contains a second order magnitude spring, many karst features, poorly drained swamps, marshes, upland flatwoods, and ridge areas. The upper Hillsborough River watershed is subdivided into two major subbasins, namely, the upper Hillsborough River subbasin, and the Blackwater Creek subbasin. The Blackwater Creek subbasin includes the Itchepackesassa Creek subbasin, which in turn includes the East Canal subbasin. The upper Hillsborough River watershed is underlain by thick sequences of carbonate rock that are covered by thin surficial deposits of unconsolidated sand and sandy clay. The clay layer is breached in many places because of the karst nature of the underlying limestone, and the highly variable degree of confinement between the Upper Floridan and surficial aquifers throughout the watershed. Potentiometric-surface maps indicate good hydraulic connection between the Upper Floridan aquifer and the Hillsborough River, and a poorer connection with Blackwater and Itchepackesassa Creeks. Similar water level elevations and fluctuations in the Upper Floridan and surficial aquifers at paired wells also indicate good hydraulic connection. Calcium was the dominant ion in ground water from all wells sampled in the watershed. Nitrate concentrations were near or below the detection limit in all except two wells that may have been affected by

  4. Large enhancement of nonlinear Goos-Hänchen shifts and optical bistability due to surface plasmon excitations

    Science.gov (United States)

    Kim, Kihong

    2015-12-01

    The Goos-Hänchen shift of p wave beams incident on a metal-nonlinear dielectric bilayer in the Kretschmann configuration is studied theoretically. The reflectance, the phase of the reflection coefficient and the Goos-Hänchen shift are calculated in a numerically precise manner by using the invariant imbedding method. The Goos-Hänchen shift has been found to be able to take both extremely large positive and negative values due to surface plasmon excitations and very strong bistability and unique hysteresis phenomena appear. In addition, several previous results on the intensity dependence of the Goos-Hänchen shift are pointed out to be erroneous.

  5. Modeling of ground temperatures in South Shetlands (Antarctic Peninsula): Forcing a land surface model with the reanalysis ERA-Interim

    Science.gov (United States)

    João Rocha, Maria; Dutra, Emanuel; Vieira, Gonçalo; Miranda, Pedro; Ramos, Miguel

    2010-05-01

    This study focus on Livingston Island (South Shetlands Antarctic Peninsula), one of the Earth's regions where warming has been more significant in the last 50 years. Our work is integrated in a project focusing on studying the influence of climate change on permafrost temperatures, which includes systematic and long-term terrain monitoring and also modeling using land surface models. A contribution will be the evaluation of the possibilities for using land surface modeling approaches to areas of the Antarctic Peninsula with lack of data on observational meteorological forcing data, as well as on permafrost temperatures. The climate variability of the Antarctic Peninsula region was studied using the new reanalysis product from European Centre for Medium-Range Weather Forecasts (ECMWF) Era-Interim and observational data from boreholes run by our group. Monthly and annual cycles of near surface climate variables are compared. The modeling approach includes the HTESSEL (Hydrology Tiled ECMWF Scheme for Surface Exchanges over Land) forced with ERA-Interim for modeling ground temperatures in the study region. The simulation results of run of HTESSEL are compared against soil temperature observations. The results show a favorable match between simulated and observed soil temperatures. The use of different forcing parameters is compared and the model vs. observation results from different results is analyzed. The main variable needing further improvement in the modeling is snow cover. The developed methodology provides a good tool for the analysis of the influence of climate variability on permafrost of the Maritime Antarctic.

  6. Ground and surface temperature variability for remote sensing of soil moisture in a heterogeneous landscape

    Science.gov (United States)

    Giraldo, M.A.; Bosch, D.; Madden, M.; Usery, L.; Finn, M.

    2009-01-01

    At the Little River Watershed (LRW) heterogeneous landscape near Tifton Georgia US an in situ network of stations operated by the US Department of Agriculture-Agriculture Research Service-Southeast Watershed Research Lab (USDA-ARS-SEWRL) was established in 2003 for the long term study of climatic and soil biophysical processes. To develop an accurate interpolation of the in situ readings that can be used to produce distributed representations of soil moisture (SM) and energy balances at the landscape scale for remote sensing studies, we studied (1) the temporal and spatial variations of ground temperature (GT) and infra red temperature (IRT) within 30 by 30 m plots around selected network stations; (2) the relationship between the readings from the eight 30 by 30 m plots and the point reading of the network stations for the variables SM, GT and IRT; and (3) the spatial and temporal variation of GT and IRT within agriculture landuses: grass, orchard, peanuts, cotton and bare soil in the surrounding landscape. The results showed high correlations between the station readings and the adjacent 30 by 30 m plot average value for SM; high seasonal independent variation in the GT and IRT behavior among the eight 30 by 30 m plots; and site specific, in-field homogeneity in each 30 by 30 m plot. We found statistical differences in the GT and IRT between the different landuses as well as high correlations between GT and IRT regardless of the landuse. Greater standard deviations for IRT than for GT (in the range of 2-4) were found within the 30 by 30 m, suggesting that when a single point reading for this variable is selected for the validation of either remote sensing data or water-energy models, errors may occur. The results confirmed that in this landscape homogeneous 30 by 30 m plots can be used as landscape spatial units for soil moisture and ground temperature studies. Under this landscape conditions small plots can account for local expressions of environmental

  7. A new accurate ground-state potential energy surface of ethylene and predictions for rotational and vibrational energy levels

    Energy Technology Data Exchange (ETDEWEB)

    Delahaye, Thibault, E-mail: thibault.delahaye@univ-reims.fr; Rey, Michaël, E-mail: michael.rey@univ-reims.fr; Tyuterev, Vladimir G. [Groupe de Spectrométrie Moléculaire et Atmosphérique, UMR CNRS 7331, BP 1039, F-51687, Reims Cedex 2 (France); Nikitin, Andrei [Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, Russian Academy of Sciences, 634055 Tomsk, Russia and Quamer, State University of Tomsk (Russian Federation); Szalay, Péter G. [Institute of Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518 Budapest (Hungary)

    2014-09-14

    In this paper we report a new ground state potential energy surface for ethylene (ethene) C{sub 2}H{sub 4} obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82 542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C{sub 2}H{sub 4} molecule was obtained with a RMS(Obs.–Calc.) deviation of 2.7 cm{sup −1} for fundamental bands centers and 5.9 cm{sup −1} for vibrational bands up to 7800 cm{sup −1}. Large scale vibrational and rotational calculations for {sup 12}C{sub 2}H{sub 4}, {sup 13}C{sub 2}H{sub 4}, and {sup 12}C{sub 2}D{sub 4} isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm{sup −1} are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of {sup 13}C{sub 2}H{sub 4} and {sup 12}C{sub 2}D{sub 4} and rovibrational levels of {sup 12}C{sub 2}H{sub 4}.

  8. Comparison of the surface energy budget between regions of seasonally frozen ground and permafrost on the Tibetan Plateau

    Science.gov (United States)

    Gu, Lianglei; Yao, Jimin; Hu, Zeyong; Zhao, Lin

    2015-02-01

    Surface energy budgets were calculated using turbulent flux observation data and meteorological gradient data collected in 2008 from two sites: BJ, located in a seasonally frozen ground region, and Tanggula, located in a permafrost region. In 2008, the energy closure ratios for the BJ and Tanggula sites were 0.74 and 0.73, respectively, using 30-min instantaneous energy flux data but 0.87 and 0.99, respectively, using daily average energy flux data. Therefore, the energy closure status is related to the time scale that is used for the study. The variation in the surface energy budget at the two sites was similar: The sensible heat flux (Hs) was relatively high in spring and reduced in summer but gradually increased in autumn. The latent heat flux (LE) was higher in summer and autumn but lower in winter and spring. Comparably, the starting time for the significant increase in LE occurred earlier at the Tanggula site than that at the BJ site, because the freezing and thawing progress of the active layer of permafrost at Tanggula site significantly affected the Hs and LE distributions, but the freezing and thawing processes of the soil at BJ site did not significantly affect the Hs and LE distributions. The monsoon significantly affected the variation in Hs and LE at both the BJ and Tanggula sites. Regarding the diurnal variation of the energy budget at the two sites, the daily maximum of net radiation (Rn) occurred at approximately 14:00 Beijing Time, and the daily maximum of ground heat flux (G0) was earlier than those of Hs and LE. The albedo and Bowen ratio for the two sites were both low in summer but high in winter. The albedo increased significantly but the Bowen ratio became lower or even negative when the surface was covered with deep snow.

  9. Mapping of the cumulative β-ray dose on the ground surface surrounding the Fukushima area

    Science.gov (United States)

    Endo, Satoru; Kajimoto, Tsuyoshi; Tanaka, Kenichi; Nguyen, Thanh T.; Hayashi, Gohei; Imanaka, Tetsuji

    2015-01-01

    A large amount of the fission products released by the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident on 11 March 2011 was deposited in a wide area from Tohoku to northern Kanto. A map of the estimated cumulative β-ray dose (70 μm dose equivalent) on the soil surface for one year after the FDNPP accident has been prepared using previously reported calculation methods and the 2-km mesh survey data by MEXT. From this map of estimated dose, areas with a high cumulative β-ray dose on the soil surface for one year after the FDNPP accident were found to be located in the Akogi-Teshichiro to Akogi-Kunugidaira region in Namie Town, and in the southern Futaba Town to the northern Tomioka Town region. The highest estimated cumulative β-ray dose was 710 mSv for one year at Akogi-Teshichiro, Namie Town. PMID:26519736

  10. Type of Ground Surface during Plyometric Training Affects the Severity of Exercise-Induced Muscle Damage

    Directory of Open Access Journals (Sweden)

    Hamid Arazi

    2016-03-01

    Full Text Available The purpose of this study was to compare the changes in the symptoms of exercise-induced muscle damage from a bout of plyometric exercise (PE; 10 × 10 vertical jumps performed in aquatic, sand and firm conditions. Twenty-four healthy college-aged men were randomly assigned to one of three groups: Aquatic (AG, n = 8, Sand (SG, n = 8 and Firm (FG, n = 8. The AG performed PE in an aquatic setting with a depth of ~130 cm. The SG performed PE on a dry sand surface at a depth of 20 cm, and the FG performed PE on a 10-cm-thick wooden surface. Plasma creatine kinase (CK activity, delayed onset muscle soreness (DOMS, knee range of motion (KROM, maximal isometric voluntary contraction (MIVC of the knee extensors, vertical jump (VJ and 10-m sprint were measured before and 24, 48 and 72 h after the PE. Compared to baseline values, FG showed significantly (p < 0.05 greater changes in CK, DOMS, and VJ at 24 until 48 h. The MIVC decreased significantly for the SG and FG at 24 until 48 h post-exercise in comparison to the pre-exercise values. There were no significant (p > 0.05 time or group by time interactions in KROM. In the 10-m sprint, all the treatment groups showed significant (p < 0.05 changes compared to pre-exercise values at 24 h, and there were no significant (p > 0.05 differences between groups. The results indicate that PE in an aquatic setting and on a sand surface induces less muscle damage than on a firm surface. Therefore, training in aquatic conditions and on sand may be beneficial for the improvement of performance, with a concurrently lower risk of muscle damage and soreness.

  11. Commons problems, common ground: Earth-surface dynamics and the social-physical interdisciplinary frontier

    Science.gov (United States)

    Lazarus, E.

    2015-12-01

    In the archetypal "tragedy of the commons" narrative, local farmers pasture their cows on the town common. Soon the common becomes crowded with cows, who graze it bare, and the arrangement of open access to a shared resource ultimately fails. The "tragedy" involves social and physical processes, but the denouement depends on who is telling the story. An economist might argue that the system collapses because each farmer always has a rational incentive to graze one more cow. An ecologist might remark that the rate of grass growth is an inherent control on the common's carrying capacity. And a geomorphologist might point out that processes of soil degradation almost always outstrip processes of soil production. Interdisciplinary research into human-environmental systems still tends to favor disciplinary vantages. In the context of Anthropocene grand challenges - including fundamental insight into dynamics of landscape resilience, and what the dominance of human activities means for processes of change and evolution on the Earth's surface - two disciplines in particular have more to talk about than they might think. Here, I use three examples - (1) beach nourishment, (2) upstream/downstream fluvial asymmetry, and (3) current and historical "land grabbing" - to illustrate a range of interconnections between physical Earth-surface science and common-pool resource economics. In many systems, decision-making and social complexity exert stronger controls on landscape expression than do physical geomorphological processes. Conversely, human-environmental research keeps encountering multi-scale, emergent problems of resource use made 'common-pool' by water, nutrient and sediment transport dynamics. Just as Earth-surface research can benefit from decades of work on common-pool resource systems, quantitative Earth-surface science can make essential contributions to efforts addressing complex problems in environmental sustainability.

  12. Seismic interferometry of railroad induced ground motions: body and surface wave imaging

    Science.gov (United States)

    Quiros, Diego A.; Brown, Larry D.; Kim, Doyeon

    2016-04-01

    Seismic interferometry applied to 120 hr of railroad traffic recorded by an array of vertical component seismographs along a railway within the Rio Grande rift has recovered surface and body waves characteristic of the geology beneath the railway. Linear and hyperbolic arrivals are retrieved that agree with surface (Rayleigh), direct and reflected P waves observed by nearby conventional seismic surveys. Train-generated Rayleigh waves span a range of frequencies significantly higher than those recovered from typical ambient noise interferometry studies. Direct P-wave arrivals have apparent velocities appropriate for the shallow geology of the survey area. Significant reflected P-wave energy is also present at relatively large offsets. A common midpoint stack produces a reflection image consistent with nearby conventional reflection data. We suggest that for sources at the free surface (e.g. trains) increasing the aperture of the array to record wide angle reflections, in addition to longer recording intervals, might allow the recovery of deeper geological structure from railroad traffic. Frequency-wavenumber analyses of these recordings indicate that the train source is symmetrical (i.e. approaching and receding) and that deeper refracted energy is present although not evident in the time-offset domain. These results confirm that train-generated vibrations represent a practical source of high-resolution subsurface information, with particular relevance to geotechnical and environmental applications.

  13. Monitoring of the ground surface temperature and the active layer in NorthEastern Canadian permafrost areas using remote sensing data assimilated in a climate land surface scheme.

    Science.gov (United States)

    Marchand, N.; Royer, A.; Krinner, G.; Roy, A.

    2014-12-01

    Projected future warming is particularly strong in the Northern high latitudes where increases of temperatures are up to 2 to 6 °C. Permafrost is present on 25 % of the northern hemisphere lands and contain high quantities of « frozen » carbon, estimated at 1400 Gt (40 % of the global terrestrial carbon). The aim of this study is to improve our understanding of the climate evolution in arctic areas, and more specifically of land areas covered by snow. The objective is to describe the ground temperature year round including under snow cover, and to analyse the active layer thickness evolution in relation to the climate variability. We use satellite data (fusion of MODIS land surface temperature « LST » and microwave AMSR-E brightness temperature « Tb ») assimilated in the Canadian Land Surface Scheme (CLASS) of the Canadian climate model coupled with a simple radiative transfer model (HUT). This approach benefits from the advantages of each of the data type in order to complete two objectives : 1- build a solid methodology for retrieving the ground temperature, with and without snow cover, in taïga and tundra areas ; 2 - from those retrieved ground temperatures, derive the summer melt duration and the active layer depth. We describe the coupling of the models and the methodology that adjusts the meteorological input parameters of the CLASS model (mainly air temperature and precipitations derived from the NARR database) in order to minimise the simulated LST and Tb ouputs in comparison with satellite measurements. Using ground-based meteorological data as validation references in NorthEastern Canadian tundra, the results show that the proposed approach improves the soil temperatures estimates when using the MODIS LST and Tb at 10 and 19 GHz to constrain the model in comparison with the model outputs without satellite data. Error analysis is discussed for the summer period (2.5 - 4 K) and for the snow covered winter period (2 - 3.5 K). Further steps are

  14. Results of ground-water, surface-water, and water-chemistry monitoring, Black Mesa area, northeastern Arizona, 1994

    Science.gov (United States)

    Littin, G.R.; Monroe, S.A.

    1995-01-01

    The Black Mesa monitoring program is designed to document long-term effects of ground-water pumping from the N aquifer by industrial and municipal users. The N aquifer is the major source of water in the 5,400-square-mile Black Mesa area, and the ground water occurs under confined and unconfined conditions. Monitoring activities include continuous and periodic measurements of (1) ground-water pumpage from the confined and unconfined areas of the aquifer, (2) ground-water levels in the confined and unconfined areas of the aquifer, (3) surface-water discharge, and (4) chemistry of the ground water and surface water. In 1994, ground-water withdrawals for industrial and municipal use totaled about 7,000 acre-feet, which is an 8-percent increase from the previous year. Pumpage from the confined part of the aquifer increased by about 9 percent to 5,400 acre-feet, and pumpage from the unconfined part of the aquifer increased by about 2 percent to 1,600 acre-feet. Water-level declines in the confined area during 1994 were recorded in 10 of 16 wells, and the median change was a decline of about 2.3 feet as opposed to a decline of 3.3 feet for the previous year. The median change in water levels in the unconfined area was a rise of 0.1 foot in 1994 as opposed to a decline of 0.5 foot in 1993. Measured low-flow discharge along Moenkopi Wash decreased from 3.0 cubic feet per second in 1993 to 2.9 cubic feet per second in 1994. Eleven low-flow measurements were made along Laguna Creek between Tsegi, Arizona, and Chinle Wash to determine the amount of discharge that would occur as seepage from the N aquifer under optimal base-flow conditions. Discharge was 5.6 cubic feet per second near Tsegi and 1.5 cubic feet per second above the confluence with Chinle Wash. Maximum discharge was 5.9 cubic feet per second about 4 miles upstream from Dennehotso. Discharge was measured at three springs. The changes in discharge at Burro and Whisky Springs were small and within the uncertainty of

  15. Mapping ground surface deformation using temporarily coherent point SAR interferometry: Application to Los Angeles Basin

    Science.gov (United States)

    Zhang, L.; Lu, Zhiming; Ding, X.; Jung, H.-S.; Feng, G.; Lee, C.-W.

    2012-01-01

    Multi-temporal interferometric synthetic aperture radar (InSAR) is an effective tool to detect long-term seismotectonic motions by reducing the atmospheric artifacts, thereby providing more precise deformation signal. The commonly used approaches such as persistent scatterer InSAR (PSInSAR) and small baseline subset (SBAS) algorithms need to resolve the phase ambiguities in interferogram stacks either by searching a predefined solution space or by sparse phase unwrapping methods; however the efficiency and the success of phase unwrapping cannot be guaranteed. We present here an alternative approach - temporarily coherent point (TCP) InSAR (TCPInSAR) - to estimate the long term deformation rate without the need of phase unwrapping. The proposed approach has a series of innovations including TCP identification, TCP network and TCP least squares estimator. We apply the proposed method to the Los Angeles Basin in southern California where structurally active faults are believed capable of generating damaging earthquakes. The analysis is based on 55 interferograms from 32 ERS-1/2 images acquired during Oct. 1995 and Dec. 2000. To evaluate the performance of TCPInSAR on a small set of observations, a test with half of interferometric pairs is also performed. The retrieved TCPInSAR measurements have been validated by a comparison with GPS observations from Southern California Integrated GPS Network. Our result presents a similar deformation pattern as shown in past InSAR studies but with a smaller average standard deviation (4.6. mm) compared with GPS observations, indicating that TCPInSAR is a promising alternative for efficiently mapping ground deformation even from a relatively smaller set of interferograms. ?? 2011.

  16. Chromium speciation and fractionation in ground and surface waters in the vicinity of chromite ore processing residue disposal sites.

    Science.gov (United States)

    Farmer, John G; Thomas, Rhodri P; Graham, Margaret C; Geelhoed, Jeanine S; Lumsdon, David G; Paterson, Edward

    2002-04-01

    Chromium concentrations of up to 91 mg l(-1) were found by ICP-OES for ground water from nine boreholes at four landfill sites in an area of S.E. Glasgow/S. Lanarkshire where high-lime chromite ore processing residue (COPR) from a local chemical works had been deposited from 1830 to 1968. Surface water concentrations of up to 6.7 mg l(-1) in a local tributary stream fell to 0.11 mg l(-1) in the River Clyde. Two independent techniques of complexation/colorimetry and speciated isotope dilution mass spectrometry (SIDMS) showed that Cr was predominantly (>90%) in hexavalent form (CrVI) as CrO4(2-), as anticipated at the high pH (7.5-12.5) of the sites. Some differences between the implied and directly determined concentrations of dissolved CrIII, however, appeared related to the total organic carbon (TOC) content. This was most significant for the ground water from one borehole that had the highest TOC concentration of 300 mg l(-1) and at which ultrafiltration produced significant decreases in Cr concentration with decreasing size fractions, e.g. complex. This showed for the main Cr-containing fraction, 100 kDa-0.45 microm, that the Cr was associated with a dark brown band characteristic of organic (humic) matter. Comparison of gel electrophoresis and FTIR results for ultrafilter retentates of ground water from this borehole with those for a borehole at another site where CrVI predominated suggested the influence of carboxylate groups, both in reducing CrVI and in forming soluble CrIII-humic complexes. The implications of this for remediation strategies (especially those based on the addition of organic matter) designed to reduce highly mobile and carcinogenic Cr(VI)O4(2-) to the much less harmful CrIII as insoluble Cr(OH)3 are discussed.

  17. The study of coastal ground surfaces to predict the ways of increasing efficiency of research mobile robots

    Science.gov (United States)

    Makarov, Vladimir; Kurkin, Andrey; Belyalov, Vladimir; Tyugin, Dmitry; Zezyulin, Denis

    2017-04-01

    The increase in spatial scales of studying coastal areas can be achieved by the use of mobile robotic systems (MRS) equipped with scanning equipment, video inspection system and positioning system. The project aims at increasing the capabilities for designing effective ground MRS through the use of advanced methods of forecasting characteristics of vehicle-terrain interaction in coastal zones, where hydrosphere, lithosphere, atmosphere and biosphere interact. In the period from 14 May to 18 June 2016 there was organized the expedition to Sakhalin Island for conducting full-scale testing autonomous MRS for coastal monitoring and forecasting marine natural disasters [Kurkin A.A., Zeziulin D.V., Makarov V.S., Zaitsev A.I., Belyaev A.M., Beresnev P.O., Belyakov V.V., Pelinovsky E.N., Tyugin D.Yu. Investigations of coastal areas of the Okhotsk sea using a ground mobile robot // Ecological systems and devices. 2016. No. 8. P. 11-17]. Within the framework of the expedition specific areas of terrain in the vicinity of Cape Svobodny were investigated (with the support of SRB AMR FEB RAS). Terrain areas were studied from the standpoint of possibility of the MRS movement. As a result of measuring all the necessary data on the physical-mechanical and geometric characteristics of the coastal zones, required to calculate the force factors acting on the MRS, and, accordingly, the parameters of its motion were received. The obtained data will be used for developing new statistical models of the physical-mechanical and geometrical characteristics of the coastal ground surfaces, creating methodology for assessing the efficiency and finding ways to optimize the design of the MRS.

  18. The effects of oxalate treatment on the smear layer of ground surfaces of human dentine.

    Science.gov (United States)

    Pashley, D H; Galloway, S E

    1985-01-01

    The layer was evaluated by scanning electron microscopy and by measurement of hydraulic conductance before and after 2-min topical treatment with potassium chloride, neutral potassium oxalate, half-neutralized oxalic acid or both neutral and acidic oxalates. The treated smear layers were then re-evaluated microscopically and functionally both before and after acid challenge. The layers treated with KCl were not altered either microscopically or functionally and were susceptible to acid etching. Dentine surfaces treated with either oxalate solutions became less permeable and were acid-resistant.

  19. Site specific prediction equations for peak acceleration of ground motion due to earthquakes induced by underground mining in Legnica-Głogów Copper District in Poland

    Science.gov (United States)

    Lasocki, Stanisław

    2013-10-01

    Ground motion database from the region of Żelazny Most tailings pond, the largest in Europe ore-flotation waste repository, is used to identify ground motion prediction equations (GMPE-s) for peak horizontal and peak vertical acceleration. A GMPE model including both geometrical spreading and anelastic damping terms cannot be correctly identified and the model with only spreading term is accepted. The analysis of variance of this model's residuals with station location as grouping variable indicates that station locations contribute significantly to the observed ground motion variability. Therefore, a site specific GMPE model with relative site amplifications is assessed. Despite short distances among stations, the amplification considerably vary from point to point, up to 1.8 times for the horizontal and 3.5 times for the vertical peak amplitude. The model including site effects enhances GMPE-s fit to observations, explains more than 60% dependent variables variability and correctly accounts for site effects.

  20. Polymer bilayer formation due to specific interactions between beta-cyclodextrin and adamantane: a surface force study.

    Science.gov (United States)

    Blomberg, Eva; Kumpulainen, Atte; David, Christelle; Amiel, Catherine

    2004-11-23

    The purposes of this study are to utilize the interactions between an adamantane end-capped poly(ethylene oxide) (PEO) and a cationic polymer of beta-cyclodextrin to build polymer bilayers on negatively charged surfaces, and to investigate the interactions between such layers. The association of this system in solution has been studied by rheology, light scattering, and fluorescence measurements. It was found that the adamantane-terminated PEO (PEO-Ad) mixed with the beta-cyclodextrin polymer gives complexes where the interpolymer links are formed by specific inclusion of the adamantane groups in the beta-cyclodextrin cavities. This results in a higher viscosity of the solution and growth of intermolecular clusters. The interactions between surfaces coated with a cationized beta-cyclodextrin polymer across a water solution containing PEO-Ad polymers were studied by employing the interferometric surface force apparatus (SFA). In the first step, the interaction between mica surfaces coated with the cationized beta-cyclodextrin polymer in pure water was investigated. It was found that the beta-cyclodextrin polymer adsorbs onto mica and almost neutralizes the surface charge. The adsorbed layers of the beta-cyclodextrin polymer are rather compact, with a layer thickness of about 60 A (30 A per surface). Upon separation, a very weak attractive force is observed. The beta-cyclodextrin solution was then diluted by pure water by a factor of 3000 and a PEO-Ad polymer was introduced into the solution. Two different architectures of the PEO-Ad polymer were investigated: a four-arm structure and a linear structure. After the adsorption of the PEO polymer onto the beta-cyclodextrin layer reached equilibrium, the forces were measured again. It was found that the weak repulsive long-range force had disappeared and an attractive force caused the surfaces to jump into contact, and that the compressed layer thickness had increased. The attractive force is interpreted as being due to

  1. An Updated Estimation of Radiative Forcing due to CO2 and Its Effect on Global Surface Temperature Change

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hua; ZHANG Ruoyu; SHI Guangyu

    2013-01-01

    New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model.The stratospheric adjusted radiative forcing (ARF)due to CO2 from the year 1750 to the updated year of 2010 was found to have increased to 1.95 W m-2,which was 17% larger than that of the IPCC's 4th Assessment Report because of the rapid increase in CO2 concentrations since 2005.A new formula is proposed to accurately describe the relationship between the ARF of CO2 and its concentration.Furthermore,according to the relationship between the ARF and surface temperature change,possible changes in equilibrium surface temperature were estimated under the scenarios that the concentration of CO2 increases to 1.5,2,2.5,3,3.5 and 4 times that of the concentration in the year 2008.The result was values of +2.2℃,+3.8℃,+5.1℃,+6.2℃,+7.1℃ and +8.0℃ respectively,based on a middle-level climate sensitivity parameter of 0.8 K (W m-2)-1.Non-equilibrium surface temperature changes over the next 500 years were also calculated under two kinds of emission scenarios (pulsed and sustained emissions) as a comparison,according to the Absolute Global Temperature change Potential (AGTP) of CO2.Results showed that CO2 will likely continue to contribute to global warming if no emission controls are imposed,and the effect on the Earth-atmosphere system will be difficult to restore to its original level.

  2. Alteration of the carbon and nitrogen isotopic composition in the Martian surface rocks due to cosmic ray exposure

    Science.gov (United States)

    Pavlov, A. A.; Pavlov, A. K.; Ostryakov, V. M.; Vasilyev, G. I.; Mahaffy, P.; Steele, A.

    2014-06-01

    13C/12C and 15N/14N isotopic ratios are pivotal for our understanding of the Martian carbon cycle, history of the Martian atmospheric escape, and origin of the organic compounds on Mars. Here we demonstrate that the carbon and nitrogen isotopic composition of the surface rocks on Mars can be significantly altered by the continuous exposure of Martian surface to cosmic rays. Cosmic rays can effectively produce 13C and 15N isotopes via spallation nuclear reactions on oxygen atoms in various Martian rocks. We calculate that in the top meter of the Martian rocks, the rates of production of both 13C and 15N due to galactic cosmic rays (GCRs) exposure can vary within 1.5-6 atoms/cm3/s depending on rocks' depth and chemical composition. We also find that the average solar cosmic rays can produce carbon and nitrogen isotopes at a rate comparable to GCRs in the top 5-10 cm of the Martian rocks. We demonstrate that if the total carbon content in a surface Martian rock is Mars can explain its high-temperature heavy nitrogen isotopic composition (15N/14N). Applications to Martian meteorites and the current Mars Science Laboratory mission are discussed.

  3. Alteration of the Carbon and Nitrogen Isotopic Composition in the Martian Surface Rocks Due to Cosmic Ray Exposure

    Science.gov (United States)

    Pavlov, A. A.; Pavlov, A. K.; Ostryakov, V. M.; Vasilyev, G. I.; Mahaffy, P.; Steele, A.

    2014-01-01

    C-13/C-12 and N-15/N-14 isotopic ratios are pivotal for our understanding of the Martian carbon cycle, history of the Martian atmospheric escape, and origin of the organic compounds on Mars. Here we demonstrate that the carbon and nitrogen isotopic composition of the surface rocks on Mars can be significantly altered by the continuous exposure of Martian surface to cosmic rays. Cosmic rays can effectively produce C-13 and N-15 isotopes via spallation nuclear reactions on oxygen atoms in various Martian rocks. We calculate that in the top meter of the Martian rocks, the rates of production of both C-13 and N-15 due to galactic cosmic rays (GCRs) exposure can vary within 1.5-6 atoms/cm3/s depending on rocks' depth and chemical composition. We also find that the average solar cosmic rays can produce carbon and nitrogen isotopes at a rate comparable to GCRs in the top 5-10 cm of the Martian rocks. We demonstrate that if the total carbon content in a surface Martian rock is rocks with relatively short exposure ages (e.g., 100 million years), cosmogenic changes in N-15/N-14 ratio are still very significant. We also show that a short exposure to cosmic rays of Allan Hills 84001 while on Mars can explain its high-temperature heavy nitrogen isotopic composition (N-15/N-14). Applications to Martian meteorites and the current Mars Science Laboratory mission are discussed.

  4. The CMS Experiment: on and under Ground Motions of Structures Due to the Magnetic Field Forces as Observed by the Link Alignment System

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Arce, J.; Barcala, J. M.; Calvo, E.; Ferrando, A.; Josa, M. I.; Molinero, A.; Navarrete, J.; Oller, J. C.; Yuste, C.; Brochero, J.; Calderon, A.; Fernandez, M. G.; Gomez, G.; Gonzalez-Sanchez, F. J.; Martinez-Ribero, C.; Matorras, F.; Rodrigo, T.; Rui-Arbol, P.; Scodellaro, L.; Sobron, M.; Vila, I.; Virto, A. L.; Fernandez, J.

    2010-05-01

    This document describes results obtained from the Link Alignment System data recorded during the CMS Magnet Test (at SX5 on ground Hall) and the CRAFT08 and 09 periods data taking in the point P5 (UX5), 100 m underground. A brief description of the system is followed by the discussion of the detected relative displacements (from micrometres to centimetres) between detector elements and rotation of detector structures (from microradiants to milliradiants). Observed motions are studied as functions of the magnetic fi eld intensity. Comparisons between recorded data on and under ground are made. (Author) 23 refs.

  5. Pesticide levels in ground and surface waters of Primavera do Leste Region, Mato Grosso, Brazil.

    Science.gov (United States)

    Dores, Eliana F G C; Carbo, Leandro; Ribeiro, Maria L; De-Lamonica-Freire, Ermelinda M

    2008-08-01

    Residues of the herbicides simazine, metribuzin, metolachlor, trifluralin, atrazine, and two metabolites of atrazine, deisopropylatrazine (DIA) and deethylatrazine (DEA), are surveyed in the surface and groundwater of the Primavera do Leste region, Mato Grosso, Brazil during September and December 1998 and April 1999. Different water source sampling stations of groundwater (irrigation water well, drinking water well, and water hole) and surface water (dam and river) are set up based on agricultural land use. A solid-phase extraction procedure followed by gas chromatography-nitrogen-phosphorus detection is used for the determination of these compounds. All compounds are detected at least once in water samples. A temporal trend of pesticide contamination is observed, with the highest contamination frequency occurring in December during the main application season. Metribuzin shows the highest individual detection frequencies throughout the monitoring period, followed by metolachlor, simazine, and DEA. The maximum mean concentrations of pesticides in this study are in the range from 0.14 to 1.7 microg/L. We deduct that the contamination of water resources is predominantly caused by non-point pollution of pesticides used in intensive cash-crop cultures of the Cerrado area. Therefore, a continuous monitoring of pesticide concentrations in water resources of this tropical region is necessary to detect the longer term contamination trends and developing health risks.

  6. A study of SO2 emissions and ground surface displacements at Lastarria volcano, Antofagasta Region, Northern Chile

    Science.gov (United States)

    Krewcun, Lucie G.

    Lastarria volcano (Chile) is located at the North-West margin of the 'Lazufre' ground inflation signal (37x45 km2), constantly uplifting at a rate of ˜2.5 cm/year since 1996 (Pritchard and Simons 2002; Froger et al. 2007). The Lastarria volcano has the double interest to be superimposed on a second, smaller-scale inflation signal and to be the only degassing area of the Lazufre signal. In this project, we compared daily SO2 burdens recorded by AURA's OMI mission for 2005-2010 with Ground Surface Displacements (GSD) calculated from the Advanced Synthetic Aperture Radar (ASAR) images for 2003-2010. We found a constant maximum displacement rate of 2.44 cm/year for the period 2003-2007 and 0.80- 0.95 cm/year for the period 2007-2010. Total SO 2 emitted is 67.0 kT for the period 2005-2010, but detection of weak SO2 degassing signals in the Andes remains challenging owing to increased noise in the South Atlantic radiation Anomaly region.

  7. Simultaneous retrieval of aerosol and surface optical properties from combined airborne- and ground-based direct and diffuse radiometric measurements

    Directory of Open Access Journals (Sweden)

    C. K. Gatebe

    2009-12-01

    Full Text Available This paper presents a new method for simultaneously retrieving aerosol and surface reflectance properties from combined airborne and ground-based direct and diffuse radiometric measurements. The method is based on the standard Aerosol Robotic Network (AERONET method for retrieving aerosol size distribution, complex index of refraction, and single scattering albedo, but modified to retrieve aerosol properties in two layers, below and above the aircraft, and parameters on surface optical properties from combined datasets (Cloud Absorption Radiometer, CAR, and AERONET data. A key advantage of this method is the inversion of all available spectral and angular data at the same time, while accounting for the influence of noise in the inversion procedure using statistical optimization. The wide spectral (0.34–2.30 μm and angular range (180° of the CAR instrument, combined with observations from an AERONET sunphotometer, provide sufficient measurement constraints for characterizing aerosol and surface properties with minimal assumptions. The robustness of the method was tested on observations made during four different field campaigns: (a the Southern African Regional Science Initiative 2000 over Mongu, Zambia, (b the Intercontinental Transport Experiment-Phase B over Mexico City, Mexico (c Cloud and Land Surface Interaction Campaign over the Atmospheric Radiation Measurement (ARM Central Facility, Oklahoma, USA, and (d the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS over Elson Lagoon in Barrow, Alaska, USA. The four areas are dominated by different surface characteristics and aerosol types, and therefore provide good test cases for the new inversion method.

  8. Simultaneous retrieval of aerosol and surface optical properties from combined airborne- and ground-based direct and diffuse radiometric measurements

    Directory of Open Access Journals (Sweden)

    C. K. Gatebe

    2010-03-01

    Full Text Available This paper presents a new method for simultaneously retrieving aerosol and surface reflectance properties from combined airborne and ground-based direct and diffuse radiometric measurements. The method is based on the standard Aerosol Robotic Network (AERONET method for retrieving aerosol size distribution, complex index of refraction, and single scattering albedo, but modified to retrieve aerosol properties in two layers, below and above the aircraft, and parameters on surface optical properties from combined datasets (Cloud Absorption Radiometer (CAR and AERONET data. A key advantage of this method is the inversion of all available spectral and angular data at the same time, while accounting for the influence of noise in the inversion procedure using statistical optimization. The wide spectral (0.34–2.30 μm and angular range (180° of the CAR instrument, combined with observations from an AERONET sunphotometer, provide sufficient measurement constraints for characterizing aerosol and surface properties with minimal assumptions. The robustness of the method was tested on observations made during four different field campaigns: (a the Southern African Regional Science Initiative 2000 over Mongu, Zambia, (b the Intercontinental Transport Experiment-Phase B over Mexico City, Mexico (c Cloud and Land Surface Interaction Campaign over the Atmospheric Radiation Measurement (ARM Central Facility, Oklahoma, USA, and (d the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS over Elson Lagoon in Barrow, Alaska, USA. The four areas are dominated by different surface characteristics and aerosol types, and therefore provide good test cases for the new inversion method.

  9. Assessment of dry season surface, ground, and treated water quality in the Cape Coast municipality of Ghana.

    Science.gov (United States)

    Quagraine, E K; Adokoh, C K

    2010-01-01

    This aim of this monitoring was to assess water quality in a dry season for the Cape Coast municipality in Ghana, which has been experiencing chronic water shortages. Fifteen different sampling stations--four surface, five ground, and six tap water samples--were analyzed for physicochemical and microbiological parameters during January to April 2005. Levels or trends in water quality that may be deleterious to sensitive water uses, including drinking, irrigation, and livestock watering have been noted with reference to well-established guidelines. Exceedances to some health-based drinking water guidelines included positive coliform for various water samples; pH for all groundwater samples (pH 5.9+/-0.3); conductivity for 50% groundwater; color for about a third of groundwater and tap water; Mn for 44% tap water, 67% groundwater, and 50% surface water samples. The World Health Organization laundry staining Fe guideline of 0.3 mg/l was exceeded by 75% of surface water, 44% tap water, and 53% groundwater samples. The corresponding Mn guideline of 0.1 mg/l was exceeded by all the water samples. Respectively, all surface water samples and also 75% of the surface water exceeded some known Cu and Zn guideline for the protection of aquatic life. Compared to some historic data for Fosu Lagoon, the current study shows a lowering of approximately 1 pH unit, increase of approximately 65% NH3, one to two orders of magnitude increase in PO4(3-), and more than two orders of magnitude increase in NO3-. In several instances, tap water samples collected at the consumers' end of the distribution system did not reflect on the true quality of the treated water. Mn, SO4(2-), PO4(3-), Cu, and Zn were among the chemical contaminations observed to occur in the distribution system.

  10. Areal-averaged and Spectrally-resolved Surface Albedo from Ground-based Transmission Data Alone: Toward an Operational Retrieval

    Energy Technology Data Exchange (ETDEWEB)

    Kassianov, Evgueni I.; Barnard, James C.; Flynn, Connor J.; Riihimaki, Laura D.; Michalsky, Joseph; Hodges, G. B.

    2014-08-22

    We present here a simple retrieval of the areal-averaged and spectrally resolved surface albedo using only ground-based measurements of atmospheric transmission under fully overcast conditions. Our retrieval is based on a one-line equation and widely accepted assumptions regarding the weak spectral dependence of cloud optical properties in the visible and near-infrared spectral range. The feasibility of our approach for the routine determinations of albedo is demonstrated for different landscapes with various degrees of heterogeneity using three sets of measurements:(1) spectrally resolved atmospheric transmission from Multi-Filter Rotating Shadowband Radiometer (MFRSR) at wavelength 415, 500, 615, 673, and 870 nm, (2) tower-based measurements of local surface albedo at the same wavelengths, and (3) areal-averaged surface albedo at four wavelengths (470, 560, 670 and 860 nm) from collocated and coincident Moderate Resolution Imaging Spectroradiometer (MODIS) observations. These integrated datasets cover both long (2008-2013) and short (April-May, 2010) periods at the ARM Southern Great Plains (SGP) site and the NOAA Table Mountain site, respectively. The calculated root mean square error (RMSE), which is defined here as the root mean squared difference between the MODIS-derived surface albedo and the retrieved area-averaged albedo, is quite small (RMSE≤0.01) and comparable with that obtained previously by other investigators for the shortwave broadband albedo. Good agreement between the tower-based daily averages of surface albedo for the completely overcast and non-overcast conditions is also demonstrated. This agreement suggests that our retrieval originally developed for the overcast conditions likely will work for non-overcast conditions as well.

  11. Dynamic subsidence prediction of ground surface above salt cavern gas storage considering the creep of rock salt

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A new model is proposed to predict the dynamic subsidence of ground surface above salt cavern gas storage during the leaching and storage, which takes into account the creep of rock salt. In the model, the extended form of Gaussian curve is adopted to figure out the shape of subsidence areas. The corresponding theoretical formulas are derived. In addition, parameters are studied to investigate the surface subsidence as a function of the salt ejection rate, internal pressure, buried depth, diameter, height, running time, etc. Through an example, the subsidence of the salt cavern gas storage located at Jiangsu of China obtained by the new model was compared with those by Peter A F formula, Schober & Sroka formula and FLAC3D through simulation. The results showed the proposed model is precise and correct, and can meet the actual engineering demands. The surface subsidence is equidirectional with the increase of salt ejection rate, depth, diameter, height, and running time, but reverse to the increase of internal pressure. The depth, diameter, running time and internal pressure have great effects on the subsidence, whereas the salt ejection rate and height have little influences on it.

  12. Simultaneous investigation of blast induced ground vibration and airblast effects on safety level of structures and human in surface blasting

    Institute of Scientific and Technical Information of China (English)

    Faramarzi Farhad⇑; Ebrahimi Farsangi Mohammad Ali; Mansouri Hamid

    2014-01-01

    The significance of studying, monitoring and predicting blast induced vibration and noise level in mining and civil activities is justified in the capability of imposing damages, sense of uncertainty due to negative psychological impacts on involved personnel and also judicial complaints of local inhabitants in the nearby area. This paper presents achieved results during an investigation carried out at Sungun Copper Mine, Iran. Besides, the research also studied the significance of blast induced ground vibration and air-blast on safety aspects of nearby structures, potential risks, frequency analysis, and human response. According to the United States Bureau of Mines (USBM) standard, the attenuation equations were devel-oped using field records. A general frequency analysis and risk evaluation revealed that:94%of generated frequencies are less than 14 Hz which is within the natural frequency of structures that increases risk of damage. At the end, studies of human response showed destructive effects of the phenomena by ranging between 2.54 and 25.40 mm/s for ground vibrations and by the average value of 110 dB for noise levels which could increase sense of uncertainty among involved employees.

  13. Hydro-economic modeling of conjunctive ground and surface water use to guide sustainable basin management

    Science.gov (United States)

    Taher Kahil, Mohamed; Ward, Frank A.; Albiac, Jose; Eggleston, Jack; Sanz, David

    2016-04-01

    Water demands for irrigation, urban and environmental uses in arid and semiarid regions continue to grow, while freshwater supplies from surface and groundwater resources are becoming scarce and are expected to decline with climate change. Policymakers in these regions face hard choices on water management and policies. Hydro-economic modeling is the state-of-the art tool that could be used to guide the design and implementation of sustainable water management policies in basins. The strength of hydro-economic modeling lies in its capacity to integrate key biophysical and socio-economic components within a unified framework. A major gap in developments on hydro-economic modeling to date has been the weak integration of surface and groundwater flows, based on the theoretically correct Darcy equations used by the hydrogeological community. The modeling approach taken here is integrated, avoiding the single-tank aquifer assumption, avoiding simplified assumptions on aquifer-river linkages, and bypassing iterations among separate hydrological and economic models. The groundwater flow formulation used in this paper harnesses the standard finite difference expressions for groundwater flow and groundwater-surface water exchange developed in the USGS MODFLOW groundwater model. The methodological contribution to previous modeling efforts is the explicit specification of aquifer-river interactions, important when aquifer systems make a sizable contribution to basin resources. The modeling framework is solved completely, and information among the economic and hydrological components over all periods and locations are jointly and simultaneously determined. This novel framework is applied to the Jucar basin (Spain), which is a good experimental region for an integrated basin scale analysis. The framework is used for assessing the impacts of a range of climate change scenarios and policy choices, especially the hydrologic, land use, and economic outcomes. The modeling framework

  14. A feasibility study to estimate minimum surface-casing depths of oil and gas wells to prevent ground-water contamination in four areas of western Pennsylvania

    Science.gov (United States)

    Buckwalter, T.F.; Squillace, P.J.

    1995-01-01

    Hydrologic data were evaluated from four areas of western Pennsylvania to estimate the minimum depth of well surface casing needed to prevent contamination of most of the fresh ground-water resources by oil and gas wells. The areas are representative of the different types of oil and gas activities and of the ground-water hydrology of most sections of the Appalachian Plateaus Physiographic Province in western Pennsylvania. Approximate delineation of the base of the fresh ground-water system was attempted by interpreting the following hydrologic data: (1) reports of freshwater and saltwater in oil and gas well-completion reports, (2) water well-completion reports, (3) geophysical logs, and (4) chemical analyses of well water. Because of the poor quality and scarcity of ground-water data, the altitude of the base of the fresh ground-water system in the four study areas cannot be accurately delineated. Consequently, minimum surface-casing depths for oil and gas wells cannot be estimated with confidence. Conscientious and reliable reporting of freshwater and saltwater during drilling of oil and gas wells would expand the existing data base. Reporting of field specific conductance of ground water would greatly enhance the value of the reports of ground water in oil and gas well-completion records. Water-bearing zones in bedrock are controlled mostly by the presence of secondary openings. The vertical and horizontal discontinuity of secondary openings may be responsible, in part, for large differences in altitudes of freshwater zones noted on completion records of adjacent oil and gas wells. In upland and hilltop topographies, maximum depths of fresh ground water are reported from several hundred feet below land surface to slightly more than 1,000 feet, but the few deep reports are not substantiated by results of laboratory analyses of dissolved-solids concentrations. Past and present drillers for shallow oil and gas wells commonly install surface casing to below the

  15. Ground-water-level monitoring, basin boundaries, and potentiometric surfaces of the aquifer system at Edwards Air Force Base, California, 1992

    Science.gov (United States)

    Rewis, D.L.

    1995-01-01

    A ground-water-level monitoring program was implemented at Edwards Air Force Base, California, from January through December 1992 to monitor spatial and temporal changes in poten-tiometric surfaces that largely are affected by ground-water pumping. Potentiometric-surface maps are needed to determine the correlation between declining ground- water levels and the distribution of land subsidence. The monitoring program focused on areas of the base where pumping has occurred, especially near Rogers Lake, and involved three phases of data collection: (1) well canvassing and selection, (2) geodetic surveys, and (3) monthly ground-water-level measurements. Construction and historical water- level data were compiled for 118 wells and pi-ezometers on or near the base, and monthly ground-water-level measurements were made in 82 wells and piezometers on the base. The compiled water-level data were used in conjunction with previously collected geologic data to identify three types of no-flow boundaries in the aquifer system: structural boundaries, a principal-aquifer boundary, and ground-water divides. Heads were computed from ground-water-level measurements and land-surface altitudes and then were used to map seasonal potentiometric surfaces for the principal and deep aquifers underlying the base. Pumping has created a regional depression in the potentiometric surface of the deep aquifer in the South Track, South Base, and Branch Park well-field area. A 15-foot decline in the potentiometric surface from April to September 1992 and 20- to 30-foot drawdowns in the three production wells in the South Track well field caused locally unconfined conditions in the deep aquifer.

  16. Application of ESPRIT in Broad Beam HF Ground Wave Radar Sea Surface Current Mapping

    Institute of Scientific and Technical Information of China (English)

    Liu Dan-hong; Wu Xiong-bin; Wen Bi-yang; Cheng Feng

    2004-01-01

    HF surface wave radar system OSMAR2000 is a broad-beam sea-state detecting radar. ESPRIT (Estimation of Signal Parameters via Rotational Invariance Technique) algorithm is proposed to apply in DOA (direction of arrival) determination of sea echoes. The algorithm of ESPRIT is briefly introduced first. Then discussions are made on the technique for application in the OSMAR2000 framework. Numerical simulation results are presented to demonstrate the feasibility of radial current mapping based on this method. The algorithm manifests significant performance and computational advantages compared with that of MUSIC. Data acquired by OSMAR2000 are processed to give radial current map and the synthesized vector currents are compared with the in-situ measurement with traditional means. The results show the validity of ESPRIT application in DOA determination for broad-beam radar.

  17. W-Band Characterization of Grounded Frequency Selective Surface Arrays Composed of Nonequal Slot Length Subarrays

    Directory of Open Access Journals (Sweden)

    S. Islam

    2009-01-01

    Full Text Available We present the design and construction of Frequency Selective Surface arrays composed of two subarrays of different slot lengths. We investigated their response variations with the variation of slot length differences of the elementary sub-arrays. Such nonhomogeneous arrays cannot be simulated with Computer Aided Design (CAD programs because the boundary conditions are not fulfilled by the simulator. In infinite array simulation, the periodic boundary conditions are prescribed on the walls of the unit cell, whereas in the case of sub-arrays of unequal slot length such boundary conditions are not applicable. The CAD simulation of such combined array gives incorrect values of amplitude and phase responses. In this work, we investigate the characteristics of such complex arrays by using heuristic experimental approach. The results of the experimental approach demonstrate that the resultant reflection amplitude and phase of such complex array depend on the difference of slot lengths (ΔL of the two sub-arrays.

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

    Science.gov (United States)

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

    2016-12-01

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

  19. Surface and Ground Water Quality in Köprüören Basin (Kütahya), Turkey

    Science.gov (United States)

    Arslan, Şebnem; Çelik, Mehmet; Erdem Dokuz, Uǧur; Abadi Berhe, Berihu

    2014-05-01

    In this study, quality of the water resources in Köprüören Basin, located to the west of Kütahya city in western Anatolia, were investigated. The total catchment area of the basin is 275 km2 and it is located upstream of Kütahya and Eskişehir plains. Therefore, besides 6,000 people residing in the basin, a much larger population will be impacted by the quality of surface and groundwater resources. Groundwater occurs under confined conditions in the limestones of Pliocene units. Groundwater flow is from north to south and south to north towards Kocasu stream, which flows to Enne Dam. The surface and ground water quality in this area are negatively affected by the mining activities. In the northern part of the area, there are coal deposits present in Miocene Tunçbilek formation. Ground waters in contact with the coal deposits contain low concentrations of arsenic (up to 30 µg/l). In the southern part, the only silver deposit of Turkey is present, which is developed in metamorphic basement rocks, Early Miocene volcanics and Pliocene units near Gümüşköy (Gümüş means silver, köy means village in Turkish). The amount of silver manufactured annually in this silver plant is huge and comprises about 1% of the World's Silver Production. The wastes, enriched in cyanide, arsenic, stibnite, lead and zinc, are stored in waste pools and there is extensive leakage of these heavy metals from these pools. Therefore, surface waters, soils and plants in the affected areas contain high concentrations of arsenic, stibnite and lead. The As, Sb, Pb and Zn concentrations are up to 733 µg/l, 158 µg/l, 48 µg/l, and 286 µg/l in surface waters (in dry season), 6180 ppm, 410 ppm, 4180 ppm, 9950 ppm in soils and 809 ppm, 399 ppm, 800 ppm, 2217 ppm in plants, respectively. Today, most of the As, Sb, Pb and Zn are absorbed by the soils and only a small part are dissolved in water. However, conditions might change in future leading to desorption of these contaminants. Therefore

  20. Earthquake Response Analysis of Buildings at The Union Territory of Chandigarh, India, by using Building Vibration Observations due to Weak Earthquake Ground Motions

    Science.gov (United States)

    Takano, K.; Ito, T.; Masuda, T.; Koketsu, K.; Ramancharla, P. K.; Sangam, R.; Bodige, N.; Dasari, H. C.

    2014-12-01

    Understanding the vulnerability of built environment in highly seismic areas is an important component of earthquake risk mitigation. As part of Indo-Japan collaborative research project (DISANET) sponsored by JST and JICA, six sets of building vibration sensors have been installed in the Union Territory of Chandigarh, India. The Union Territory of Chandigarh, India is located at South of the Himalayan Frontal Belt (HFT) is in zone IV of the seismic zone map of India (BIS, 2007). In past few decades, this area has experienced several minor earthquakes and a few moderate earthquakes. In spite of being in high seismic zone, most of the buildings in Chandigarh are designed and constructed for gravity loads only disregarding seismic forces. Such kind of buildings may deteriorate in strength even when they are subjected to minor earthquakes. To understand the response of buildings to micro-tremors, vibration sensors were installed in the building of Department of Geology of Panjab University in July 2012. Subsequently 5 more buildings were instrumented by January 2014. For each building, in order to capture the overall vibration of building during earthquake, vibration sensors of 8 or 10 units are installed to the ground floor, top floor and middle floor of the building. These sensors are continuously monitoring the building vibration and recording all data which include the weak ground motion occurring from near to far earthquakes. Through these sensors, over 20 minor ground motions have been recorded during last two years. Even in these weak ground motions, it was possible to confirm the state of the building response caused by earthquakes. In this presentation, we will introduce some building vibration records caused by the weak ground motion of the earthquakes and discuss the important insights drawn from analysis of recorded data.

  1. High resolution imaging of vadose zone transport using surface and crosswell ground penetrating radar methods

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Kenneth H.; Kowalsky, Mike B.; Peterson, John E.

    2002-11-05

    To effectively clean up many contaminated sites there is a need for information on heterogeneities at scales ranging from one centimeter to tens of meters, as these features can alter contaminant transport significantly. At the Department of Energy's Hanford, Washington site heterogeneities of interest can range from localized phenomena such as silt or gravel lenses, fractures, clastic dikes, to large-scale lithologic discontinuities. In the vadose zone it is critical to understand the parameters controlling flow. These features have been suspected of leading to funneling and fingering, additional physical mechanisms that could alter and possibly accelerate the transport of contaminants to underlying groundwater. For example, it has been observed from the studies to date that over relatively short distances there are heterogeneities in the physical structure of the porous medium and structural differences between repacked soil cores and the field site from which the materials initially came (Raymond and Shdo, 1966). Analysis of cores taken from the vadose zone (i.e., soil surface to water table) has been useful in identifying localized zones of contamination. Unfortunately, these analyses are sparse (limited to a few boreholes) and extremely expensive. The high levels of radioactivity at many of the contaminated sites increase drilling and sample costs and analysis time. Cost of drilling and core analysis for the SX tank farm has exceeded $1M per borehole (50 meter deep) for sampling. The inability to track highly mobile species through the vadose zone highlights an important need: the need for methods to describe the complete vadose zone plume and to determine processes controlling accelerated contamination of groundwater at Hanford. A combination of surface and crosswell (i.e. borehole) geophysical measurements is one means to provide this information. The main questions addressed with the radar methods in this study are: (1) What parts of the vadose zone

  2. Estimating Daily Maximum and Minimum Land Air Surface Temperature Using MODIS Land Surface Temperature Data and Ground Truth Data in Northern Vietnam

    Directory of Open Access Journals (Sweden)

    Phan Thanh Noi

    2016-12-01

    Full Text Available This study aims to evaluate quantitatively the land surface temperature (LST derived from MODIS (Moderate Resolution Imaging Spectroradiometer MOD11A1 and MYD11A1 Collection 5 products for daily land air surface temperature (Ta estimation over a mountainous region in northern Vietnam. The main objective is to estimate maximum and minimum Ta (Ta-max and Ta-min using both TERRA and AQUA MODIS LST products (daytime and nighttime and auxiliary data, solving the discontinuity problem of ground measurements. There exist no studies about Vietnam that have integrated both TERRA and AQUA LST of daytime and nighttime for Ta estimation (using four MODIS LST datasets. In addition, to find out which variables are the most effective to describe the differences between LST and Ta, we have tested several popular methods, such as: the Pearson correlation coefficient, stepwise, Bayesian information criterion (BIC, adjusted R-squared and the principal component analysis (PCA of 14 variables (including: LST products (four variables, NDVI, elevation, latitude, longitude, day length in hours, Julian day and four variables of the view zenith angle, and then, we applied nine models for Ta-max estimation and nine models for Ta-min estimation. The results showed that the differences between MODIS LST and ground truth temperature derived from 15 climate stations are time and regional topography dependent. The best results for Ta-max and Ta-min estimation were achieved when we combined both LST daytime and nighttime of TERRA and AQUA and data from the topography analysis.

  3. Field experiment provides ground truth for surface nuclear magnetic resonance measurement

    Science.gov (United States)

    Knight, R.; Grunewald, E.; Irons, T.; Dlubac, K.; Song, Y.; Bachman, H.N.; Grau, B.; Walsh, D.; Abraham, J.D.; Cannia, J.

    2012-01-01

    The need for sustainable management of fresh water resources is one of the great challenges of the 21st century. Since most of the planet's liquid fresh water exists as groundwater, it is essential to develop non-invasive geophysical techniques to characterize groundwater aquifers. A field experiment was conducted in the High Plains Aquifer, central United States, to explore the mechanisms governing the non-invasive Surface NMR (SNMR) technology. We acquired both SNMR data and logging NMR data at a field site, along with lithology information from drill cuttings. This allowed us to directly compare the NMR relaxation parameter measured during logging,T2, to the relaxation parameter T2* measured using the SNMR method. The latter can be affected by inhomogeneity in the magnetic field, thus obscuring the link between the NMR relaxation parameter and the hydraulic conductivity of the geologic material. When the logging T2data were transformed to pseudo-T2* data, by accounting for inhomogeneity in the magnetic field and instrument dead time, we found good agreement with T2* obtained from the SNMR measurement. These results, combined with the additional information about lithology at the site, allowed us to delineate the physical mechanisms governing the SNMR measurement. Such understanding is a critical step in developing SNMR as a reliable geophysical method for the assessment of groundwater resources.

  4. Directional site resonances and the influence of near-surface geology on ground motion

    Science.gov (United States)

    Bonamassa, Ornella; Vidale, John E.; Houston, Heidi; Schwartz, Susan Y.

    1991-05-01

    We examine the horizontal motions at close stations from earthquakes in the Loma Prieta and Whittier Narrows sequences to study the shear wave polarizations. We use a dense, six station array recording 10 aftershocks for the former, and use two events and 11 stations across the Los Angeles area for the latter.We compute the average azimuth of strongest shaking in the shear wave as a function of frequency from 1 to 18 Hz for each record of each earthquake. The direction of shaking at a given frequency often correlates much better with an empirical site resonance direction than with the direction of shaking expected from the focal mechanism of the earthquake. The effect tends to be greatest at the frequencies that are the most amplified. This phenomenon can complicate determination of the earthquake source at frequencies higher than 1 Hz.Further, since sites only 25 meters apart show different preferred directions, very near-surface geology is probably responsible. Estimation of directional site resonances may prove useful for seismic design.

  5. Estimation of the near surface soil water content during evaporation using air-launched ground-penetrating radar

    KAUST Repository

    Moghadas, Davood

    2014-01-01

    Evaporation is an important process in the global water cycle and its variation affects the near sur-face soil water content, which is crucial for surface hydrology and climate modelling. Soil evaporation rate is often characterized by two distinct phases, namely, the energy limited phase (stage-I) and the soil hydraulic limited period (stage-II). In this paper, a laboratory experiment was conducted using a sand box filled with fine sand, which was subject to evaporation for a period of twenty three days. The setup was equipped with a weighting system to record automatically the weight of the sand box with a constant time-step. Furthermore, time-lapse air-launched ground penetrating radar (GPR) measurements were performed to monitor the evaporation process. The GPR model involves a full-waveform frequency-domain solution of Maxwell\\'s equations for wave propagation in three-dimensional multilayered media. The accuracy of the full-waveform GPR forward modelling with respect to three different petrophysical models was investigated. Moreover, full-waveform inversion of the GPR data was used to estimate the quantitative information, such as near surface soil water content. The two stages of evaporation can be clearly observed in the radargram, which indicates qualitatively that enough information is contained in the GPR data. The full-waveform GPR inversion allows for accurate estimation of the near surface soil water content during extended evaporation phases, when a wide frequency range of GPR (0.8-5.0 GHz) is taken into account. In addition, the results indicate that the CRIM model may constitute a relevant alternative in solving the frequency-dependency issue for full waveform GPR modelling.

  6. Hydrophilic anthropogenic markers for quantification of wastewater contamination in ground- and surface waters.

    Science.gov (United States)

    Kahle, Maren; Buerge, Ignaz J; Müller, Markus D; Poiger, Thomas

    2009-12-01

    Hydrophilic, persistent markers are useful to detect, locate, and quantify contamination of natural waters with domestic wastewater. The present study focused on occurrence and fate of seven marker candidates including carbamazepine (CBZ), 10,11-dihydro-10,11-dihydroxycarbamazepine (DiOH-CBZ), primidone (PMD), crotamiton (CTMT), N-acetyl-4-aminoantipyrine (AAA), N-formyl-4-aminoantipyrine (FAA), and benzotriazole (BTri) in wastewater treatment plants (WWTPs), lakes, and groundwater. In WWTPs, concentrations from 0.14 microg/L to several micrograms per liter were observed for all substances, except CTMT, which was detected at lower concentrations. Loads determined in untreated and treated wastewater indicated that removal of the potential markers in WWTPs is negligible; only BTri was partly eliminated (average 33%). In lakes, five compounds, CBZ, DiOH-CBZ, FAA, AAA, and BTri, were consistently detected in concentrations of 2 to 70 ng/L, 3 to 150 ng/L, less than the limit of quantification to 30 ng/L, 2 to 80 ng/L, and 11 to 920 ng/L, respectively. Mean per capita loads in the outflows of the lakes suggested possible dissipation in surface waters, especially of AAA and FAA. Nevertheless, concentrations of CBZ, DiOH-CBZ, and BTri correlated with the actual anthropogenic burden of the lakes by domestic wastewater, indicating that these compounds are suitable for quantification of wastewater contamination in lakes. Marker candidates were also detected in a number of groundwater samples. Carbamazepine concentrations up to 42 ng/L were observed in aquifers with significant infiltration of river water, receiving considerable wastewater discharges from WWTPs. Concentration ratios between compounds indicated some elimination of BTri and DiOH-CBZ during subsurface passage or in groundwater, while CBZ and PMD appeared to be more stable and thus are promising wastewater markers for groundwater. The wastewater burden in groundwater, estimated with the markers CBZ and PMD

  7. Dependence of implantation sequence on surface blistering characteristics due to H and He ions co-implanted in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Liang, J.H. [Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Hsieh, H.Y.; Wu, C.W. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan, ROC (China); Lin, C.M. [Department of Applied Science, National Hsinchu University of Education, Hsinchu 300, Taiwan, ROC (China)

    2015-12-15

    This study investigated surface blistering characteristics due to H and He ions co-implanted in silicon at room temperature. The H and He ion energies were 40 and 50 keV, respectively, so that their depth profiles were similar. The total implantation fluence for the H and He ions was 5 × 10{sup 16} cm{sup −2} under various fluence fractions in the H ions. The implantation sequences under investigation were He + H and H + He. Dynamic optical microscopy (DOM) was employed in order to dynamically analyze surface blistering characteristics. This study used DOM data to construct so-called time–temperature–transformation (T–T–T) curves to easily predict blistering and crater transformation at specific annealing times and temperatures. The results revealed that the curves of blister initialization, crater initialization, and crater completion in the He + H implant occurred at a lower annealing temperature but with a longer annealing time compared to those in the H + He implant. Furthermore, the threshold annealing temperatures for blister and crater formation in the He + H implant were lower than they were in the H + He implant. The size distributions of the blisters and craters in the He + H implant extended wider than those in the H + He implant. In addition, the He + H implant exhibited larger blisters and craters compared to the ones in the H + He implant. Since the former has a higher percentage of exfoliation area than the latter, it is regarded as the more optimal implantation sequence.

  8. Spectral Dependent Degradation of the Solar Diffuser on Suomi-NPP VIIRS Due to Surface Roughness-Induced Rayleigh Scattering

    Directory of Open Access Journals (Sweden)

    Xi Shao

    2016-03-01

    Full Text Available The Visible Infrared Imaging Radiometer Suite (VIIRS onboard Suomi National Polar Orbiting Partnership (SNPP uses a solar diffuser (SD as its radiometric calibrator for the reflective solar band calibration. The SD is made of Spectralon™ (one type of fluoropolymer and was chosen because of its controlled reflectance in the Visible/Near-Infrared/Shortwave-Infrared region and its near-Lambertian reflectance property. On-orbit changes in VIIRS SD reflectance as monitored by the Solar Diffuser Stability Monitor showed faster degradation of SD reflectance for 0.4 to 0.6 µm channels than the longer wavelength channels. Analysis of VIIRS SD reflectance data show that the spectral dependent degradation of SD reflectance in short wavelength can be explained with a SD Surface Roughness (length scale << wavelength based Rayleigh Scattering (SRRS model due to exposure to solar UV radiation and energetic particles. The characteristic length parameter of the SD surface roughness is derived from the long term reflectance data of the VIIRS SD and it changes at approximately the tens of nanometers level over the operational period of VIIRS. This estimated roughness length scale is consistent with the experimental result from radiation exposure of a fluoropolymer sample and validates the applicability of the Rayleigh scattering-based model. The model is also applicable to explaining the spectral dependent degradation of the SDs on other satellites. This novel approach allows us to better understand the physical processes of the SD degradation, and is complementary to previous mathematics based models.

  9. Global crop yield reductions due to surface ozone exposure: 1. Year 2000 crop production losses and economic damage

    Science.gov (United States)

    Avnery, Shiri; Mauzerall, Denise L.; Liu, Junfeng; Horowitz, Larry W.

    2011-04-01

    Exposure to elevated concentrations of surface ozone (O 3) causes substantial reductions in the agricultural yields of many crops. As emissions of O 3 precursors rise in many parts of the world over the next few decades, yield reductions from O 3 exposure appear likely to increase the challenges of feeding a global population projected to grow from 6 to 9 billion between 2000 and 2050. This study estimates year 2000 global yield reductions of three key staple crops (soybean, maize, and wheat) due to surface ozone exposure using hourly O 3 concentrations simulated by the Model for Ozone and Related Chemical Tracers version 2.4 (MOZART-2). We calculate crop losses according to two metrics of ozone exposure - seasonal daytime (08:00-19:59) mean O 3 (M12) and accumulated O 3 above a threshold of 40 ppbv (AOT40) - and predict crop yield losses using crop-specific O 3 concentration:response functions established by field studies. Our results indicate that year 2000 O 3-induced global yield reductions ranged, depending on the metric used, from 8.5-14% for soybean, 3.9-15% for wheat, and 2.2-5.5% for maize. Global crop production losses totaled 79-121 million metric tons, worth $11-18 billion annually (USD 2000). Our calculated yield reductions agree well with previous estimates, providing further evidence that yields of major crops across the globe are already being substantially reduced by exposure to surface ozone - a risk that will grow unless O 3-precursor emissions are curbed in the future or crop cultivars are developed and utilized that are resistant to O 3.

  10. MODELING THE ANOMALY OF SURFACE NUMBER DENSITIES OF GALAXIES ON THE GALACTIC EXTINCTION MAP DUE TO THEIR FIR EMISSION CONTAMINATION

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, Toshiya; Suto, Yasushi; Taruya, Atsushi; Yahata, Kazuhiro [Department of Physics, The University of Tokyo, Tokyo 113-0033 (Japan); Kayo, Issha [Department of Physics, Toho University, Funabashi, Chiba 274-8510 (Japan); Nishimichi, Takahiro, E-mail: kashiwagi@utap.phys.s.u-tokyo.ac.jp [Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa, Chiba 277-8568 (Japan)

    2015-02-01

    The most widely used Galactic extinction map is constructed assuming that the observed far-infrared (FIR) fluxes come entirely from Galactic dust. According to the earlier suggestion by Yahata et al., we consider how FIR emission of galaxies affects the SFD map. We first compute the surface number density of Sloan Digital Sky Survey (SDSS) DR7 galaxies as a function of the r-band extinction, A {sub r,} {sub SFD}. We confirm that the surface densities of those galaxies positively correlate with A {sub r,} {sub SFD} for A {sub r,} {sub SFD} < 0.1, as first discovered by Yahata et al. for SDSS DR4 galaxies. Next we construct an analytical model to compute the surface density of galaxies, taking into account the contamination of their FIR emission. We adopt a log-normal probability distribution for the ratio of 100 μm and r-band luminosities of each galaxy, y ≡ (νL){sub 100} {sub μm}/(νL) {sub r}. Then we search for the mean and rms values of y that fit the observed anomaly, using the analytical model. The required values to reproduce the anomaly are roughly consistent with those measured from the stacking analysis of SDSS galaxies. Due to the limitation of our statistical modeling, we are not yet able to remove the FIR contamination of galaxies from the extinction map. Nevertheless, the agreement with the model prediction suggests that the FIR emission of galaxies is mainly responsible for the observed anomaly. Whereas the corresponding systematic error in the Galactic extinction map is 0.1-1 mmag, it is directly correlated with galaxy clustering and thus needs to be carefully examined in precision cosmology.

  11. Ab initio potential energy surface and excited vibrational states for the electronic ground state of Li2H

    Institute of Scientific and Technical Information of China (English)

    鄢国森; 先晖; 谢代前

    1997-01-01

    A 285-pomt multi-reference configuration-interaction involving single and double excitations ( MRS DCI) potential energy surface for the electronic ground state of L12H is determined by using 6-311G (2df,2pd)basis set.A Simons-Parr-Finlan polynomial expansion is used to fit the discrete surface with a x2 of 4.64×106 The equn librium geometry occurs at Rc=0.172 nm and,LiHL1=94.10°.The dissociation energy for reaction I2H(2A)→L12(1∑g)+H(2S) is 243.910 kJ/mol,and that for reaction L12H(2A’)→HL1(1∑) + L1(2S) is 106.445 kl/mol The inversion barrier height is 50.388 kj/mol.The vibrational energy levels are calculated using the discrete variable representation (DVR) method.

  12. Effect of cloud-to-ground lightning and meteorological conditions on surface NOx and O3 in Hong Kong

    Science.gov (United States)

    Fei, Leilei; Chan, L. Y.; Bi, Xinhui; Guo, Hai; Liu, Yonglin; Lin, Qinhao; Wang, Xinming; Peng, Ping'an; Sheng, Guoying

    2016-12-01

    Cloud-to-ground (CG) lightning, meteorological conditions and corresponding surface nitrogen oxides (NOx) and ozone (O3) variations in relation to thunderstorm and lightning activities over Hong Kong at Kwai Chung (urban), Tung Chung (new town) and Tap Mun (background) during active lightning seasons from 2009 to 2013 were studied by analyzing respective air quality monitoring station data along with CG lightning and meteorological data. We observed NOx enhancement and significant O3 decline on lightning days. Influences of land use types, lightning activities and meteorological conditions on surface NOx and O3 were examined. NOx and O3 concentrations shifted towards higher and lower levels, respectively, during lightning days especially in the dominant wind directions. Principal component analysis/absolute principal component scores (PCA/APCS) method and stepwise multiple linear regression (MLR) analysis were employed to examine the influence of thunderstorm related lightning and meteorological parameters on surface NOx and O3. Wind speed was supposed to be the most important meteorological parameter affecting the concentration of NOx, and lightning activities were observed to make a positive contribution to NOx. Negative contribution of hot, cloudy and wet weather and positive contribution of wind speed were found to affect the concentration of O3. Lightning parameters were also found to make a small positive contribution to O3 concentration at Tap Mun and Tung Chung, but the net effect of lightning activities and corresponding meteorological conditions was the decrease of O3 on lightning days. Reasonably good agreement between the predicted and observed NOx and O3 values indicates that PCA/APCS-MLR is a valuable method to study the thunderstorm induced NOx and O3 variations.

  13. Interactions between surface water and ground water and effects on mercury transport in the north-central Everglades

    Science.gov (United States)

    Harvey, Judson W.; Krupa, Steven L.; Gefvert, Cynthia; Mooney, Robert H.; Choi, Jungyill; King, Susan A.; Giddings, Jefferson B.

    2002-01-01

    The hydrology of the north-central Everglades was altered substantially in the past century by canal dredging, land subsidence, ground-water pumping, and levee construction. Vast areas of seasonal and perennial wetlands were converted to uses for agriculture, light industry, and suburban development. As the catchment area for the Everglades decreased, so did the sources of water from local precipitation and runoff from surrounding uplands. Partly in response to those alterations, water-resources managers compartmentalized the remaining wetlands in the north-central Everglades into large retention basins, called Water Conservation Areas (WCAs). In spite of efforts to improve how water resources are managed, the result has been frequent periods of excessive drying out or flooding of the WCAs because the managed system does not have the same water-storage capacity as the pre-drainage Everglades. Linked to the hydrological modifications are ecological changes including large-scale invasions of cattail, loss of tree islands, and diminishing bird populations in the Everglades. Complex interactions among numerous physical, chemical, and biological factors are responsible for the long-term degradation of the ecological character of the Everglades.Over the past 15 years, a new set of smaller wetland basins, called Stormwater Treatment Areas (STAs), have been designed and constructed by water-resources engineers on the former wetlands adjacent to WCAs. The purpose of STAs is to remove excess nutrients from agricultural drainage water prior to its input to WCAs. STAs tend to be about one-tenth the size of a WCA, and they are located on former wetlands on the northwestern side of WCAs on sites that were managed as farmland for much of the twentieth century in an area referred to as the Everglades Agricultural Area, or EAA. The objective of the present investigation was to quantify interactions between surface water and ground water in the Everglades Nutrient Removal Project

  14. Effects of Different Methods on the Comparison between Land Surface and Ground Phenology—A Methodological Case Study from South-Western Germany

    Directory of Open Access Journals (Sweden)

    Gourav Misra

    2016-09-01

    Full Text Available Several methods exist for extracting plant phenological information from time series of satellite data. However, there have been only a few successful attempts to temporarily match satellite observations (Land Surface Phenology or LSP with ground based phenological observations (Ground Phenology or GP. The classical pixel to point matching problem along with the temporal and spatial resolution of remote sensing data are some of the many issues encountered. In this study, MODIS-sensor’s Normalised Differenced Vegetation Index (NDVI time series data were smoothed using two filtering techniques for comparison. Several start of season (SOS methods established in the literature, namely thresholds of amplitude, derivatives and delayed moving average, were tested for determination of LSP-SOS for broadleaf forests at a site in southwestern Germany using 2001–2013 time series of NDVI data. The different LSP-SOS estimates when compared with species-rich GP dataset revealed that different LSP-SOS extraction methods agree better with specific phases of GP, and the choice of data processing or smoothing strongly affects the LSP-SOS extracted. LSP methods mirroring late SOS dates, i.e., 75% amplitude and 1st derivative, indicated a better match in means and trends, and high, significant correlations of up to 0.7 with leaf unfolding and greening of late understory and broadleaf tree species. GP-SOS of early understory leaf unfolding partly were significantly correlated with earlier detecting LSP-SOS, i.e., 20% amplitude and 3rd derivative. Early understory SOS were, however, more difficult to detect from NDVI due to the lack of a high resolution land cover information.

  15. Bedrock geology Forsmark. Modelling stage 2.3. Description of the bedrock geological map at the ground surface

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, Michael B.; Bergman, Torbjoern (Geological Survey of Sweden, Uppsala (Sweden)); Isaksson, Hans (GeoVista AB, Luleaa (Sweden)); Petersson, Jesper (SwedPower AB, Stockholm (Sweden))

    2008-12-15

    A description of the bedrock geological map of the ground surface at the Forsmark site is presented here. This map is essentially a 2D model for the distribution of different types of rock unit on this surface. Besides showing the distribution of these rock units, the bedrock geological map also displays the distribution of some deformation zones that intersect the ground surface. It also presents information bearing on the position and form of outcrops, the location and projection of boreholes drilled during the site investigation programme, subordinate rock types, the occurrence of abandoned mines or exploration prospects, measurements of ductile structures in outcrops, inferred form lines, key minerals, and the occurrence of mylonite and cataclastic rock. Bedrock data from outcrops and excavations, airborne and ground magnetic data and information from the uppermost part of boreholes have all been used in the construction of the geological map. The description has also made use of complementary analytical data bearing on the composition and age of the rocks as well gamma-ray spectrometry and gravity data. Uncertainty in the position of the boundaries between rock units over the mapped area are addressed in a qualitative manner. Four model versions of the bedrock geological map have been delivered to SKB's GIS database (bedrock geological map, Forsmark, versions 1.1, 1.2, 2.2 and 2.3) at different times during the site investigation programme. The Forsmark area is situated along the coast of the Baltic Sea in northern Uppland, Sweden, in a region where the overall level of ductile strain in the bedrock is high. This high-strain region extends several tens of kilometres across the WNW-ENE to NW-SE strike of the rocks in this part of the Fennoscandian Shield. At Forsmark, the coastal region is composed partly of high-strain belts, which formed under amphibolite-facies metamorphic conditions, and partly of tectonic lenses, where the bedrock is also affected by

  16. The Use of Numerical Modeling to Address Surface and Subsurface Water Contamination due to Fracwater Spills in Larry's Creek, Pennsylvania

    Science.gov (United States)

    Simon, C. A.; Arjmand, S.; Abad, J. D.

    2012-12-01

    Because of its relatively low carbon dioxide emissions, natural gas is considered to be more efficient and environmentally friendly than other non-renewable fuels. As a result of this, among other factors, in recent years natural gas has become one of the world's primary energy sources. In the United States, drilling to extract natural gas has substantially increased over the past few years. In the Marcellus Shale, unconventional gas is currently extracted by using two new techniques: horizontal drilling and hydraulic fracturing. Today, fracking fluids which have been applied as part of the hydraulic fracturing process to fracture the shale rock and release the gas, pose a major environmental concern. These fluids are highly contaminated with radionuclides and toxic metals and any exposure of this highly polluted water to surface water or soil could heavily contaminate the media. The area selected for the current study is the Larry's Creek, located in Lycoming County in Pennsylvania. Larry's Creek Watershed was adversely affected by coal and iron mines activities in the 19th century. Though, the water quality in this creek was considered to be good as of 2006. Recently, oil and gas drilling activities have raised concerns about the creek's water quality again. A major environmental hazard is the freshwater contamination by frac/flowback water. Drilling companies are using impoundments on site to keep fracwater, and to store and evaporate flowback water. However, these ponds may fail or leak due to construction problems and/or accidents. Close to Saladasburg, Larry's Creek's stream was observed running rich with clay in October 19, 2011. Historical measurements show very high turbidity during this period which has raised questions about water contamination by the gas industry activities in the upper stream of the watershed. An interstate watershed agency has reported spills in Wolf Run in different drilling sites in the Larry's Creek basin. The focus of this study

  17. The crystal structure of Haloferax volcanii proliferating cell nuclear antigen reveals unique surface charge characteristics due to halophilic adaptation

    Directory of Open Access Journals (Sweden)

    Morroll Shaun

    2009-08-01

    Full Text Available Abstract Background The high intracellular salt concentration required to maintain a halophilic lifestyle poses challenges to haloarchaeal proteins that must stay soluble, stable and functional in this extreme environment. Proliferating cell nuclear antigen (PCNA is a fundamental protein involved in maintaining genome integrity, with roles in both DNA replication and repair. To investigate the halophilic adaptation of such a key protein we have crystallised and solved the structure of Haloferax volcanii PCNA (HvPCNA to a resolution of 2.0 Å. Results The overall architecture of HvPCNA is very similar to other known PCNAs, which are highly structurally conserved. Three commonly observed adaptations in halophilic proteins are higher surface acidity, bound ions and increased numbers of intermolecular ion pairs (in oligomeric proteins. HvPCNA possesses the former two adaptations but not the latter, despite functioning as a homotrimer. Strikingly, the positive surface charge considered key to PCNA's role as a sliding clamp is dramatically reduced in the halophilic protein. Instead, bound cations within the solvation shell of HvPCNA may permit sliding along negatively charged DNA by reducing electrostatic repulsion effects. Conclusion The extent to which individual proteins adapt to halophilic conditions varies, presumably due to their diverse characteristics and roles within the cell. The number of ion pairs observed in the HvPCNA monomer-monomer interface was unexpectedly low. This may reflect the fact that the trimer is intrinsically stable over a wide range of salt concentrations and therefore additional modifications for trimer maintenance in high salt conditions are not required. Halophilic proteins frequently bind anions and cations and in HvPCNA cation binding may compensate for the remarkable reduction in positive charge in the pore region, to facilitate functional interactions with DNA. In this way, HvPCNA may harness its environment as

  18. Uncertainties in surface mass and energy flux estimates due to different eddy covariance sensors and technical set-up

    Science.gov (United States)

    Arriga, Nicola; Fratini, Gerardo; Forgione, Antonio; Tomassucci, Michele; Papale, Dario

    2010-05-01

    Eddy covariance is a well established and widely used methodology for the measurement of turbulent fluxes of mass and energy in the atmospheric boundary layer, in particular to estimate CO2/H2O and heat exchange above ecologically relevant surfaces (Aubinet 2000, Baldocchi 2003). Despite its long term application and theoretical studies, many issues are still open about the effect of different experimental set-up on final flux estimates. Open issues are the evaluation of the performances of different kind of sensors (e.g. open path vs closed path infra-red gas analysers, vertical vs horizontal mounting ultrasonic anemometers), the quantification of the impact of corresponding physical corrections to be applied to get robust flux estimates taking in account all processes concurring to the measurement (e.g. the so-called WPL term, signal attenuation due to air sampling system for closed path analyser, relative position of analyser and anemometer) and the differences between several data transmission protocols used (analogue, digital RS-232, SDM). A field experiment was designed to study these issues using several instruments among those most used within the Fluxnet community and to compare their performances under conditions supposed to be critical: rainy and cold weather conditions for open-path analysers (Burba 2008), water transport and absorption at high air relative humidity conditions for closed-path systems (Ibrom, 2007), frequency sampling limits and recorded data robustness due to different transmission protocols (RS232, SDM, USB, Ethernet) and finally the effect of the displacement between anemometer and analyser using at least two identical analysers placed at different horizontal and vertical distances from the anemometer. Aim of this experiment is to quantify the effect of several technical solutions on the final estimates of fluxes measured at a point in the space and if they represent a significant source of uncertainty for mass and energy cycle

  19. Differences in rates of decrease of environmental radiation dose rates by ground surface property in Fukushima City after the Fukushima Daiichi nuclear power plant accident.

    Science.gov (United States)

    Kakamu, Takeyasu; Kanda, Hideyuki; Tsuji, Masayoshi; Kobayashi, Daisuke; Miyake, Masao; Hayakawa, Takehito; Katsuda, Shin-ichiro; Mori, Yayoi; Okouchi, Toshiyasu; Hazama, Akihiro; Fukushima, Tetsuhito

    2013-01-01

    After the Great East Japan Earthquake on 11 March 2011, the environmental radiation dose in Fukushima City increased. On 11 April, 1 mo after the earthquake, the environmental radiation dose rate at various surfaces in the same area differed greatly by surface property. Environmental radiation measurements continue in order to determine the estimated time to 50% reduction in environmental radiation dose rates by surface property in order to make suggestions for decontamination in Fukushima. The measurements were carried out from 11 April to 11 November 2011. Forty-eight (48) measurement points were selected, including four kinds of ground surface properties: grass (13), soil (5), artificial turf (7), and asphalt (23). Environmental radiation dose rate was measured at heights of 100 cm above the ground surface. Time to 50% reduction of environmental radiation dose rates was estimated for each ground surface property. Radiation dose rates on 11 November had decreased significantly compared with those on 11 April for all surface properties. Artificial turf showed the longest time to 50% reduction (544.32 d, standard error: 96.86), and soil showed the shortest (213.20 d, standard error: 35.88). The authors found the environmental radiation dose rate on artificial materials to have a longer 50% reduction time than that on natural materials. These results contribute to determining an order of priority for decontamination after nuclear disasters.

  20. Investigation of the influence of topographic irregularities and two dimensional effects on the intensity of surface ground motion with one- and two-dimensional analyses

    Directory of Open Access Journals (Sweden)

    L. Yılmazoğlu

    2013-12-01

    Full Text Available In this work, the surface ground motion that occurs during an earthquake in ground sections having different topographic forms has been examined with one and two dynamic site response analyses. One-dimensional analyses were undertaken using the Equivalent-Linear Earthquake Response Analysis program based on the equivalent linear analysis principle and the Deepsoil program which is able to make both equivalent linear and nonlinear analyses and two-dimensional analyses using the Plaxis software. The viscous damping parameters used in the dynamic site response analyses undertaken with the Plaxis software were obtained using the DeepSoil program. In the dynamic site response analyses, the synthetic acceleration over a 475 yr replication period representing the earthquakes in Istanbul was used as the basis of the bedrock ground motion. The peak ground acceleration obtained different depths of soils and acceleration spectrum values have been compared. The surface topography and layer boundaries in the 5-5' section were selected in order to examine the effect of the land topography and layer boundaries on the analysis results were flattened and compared with the actual status. The analysis results showed that the characteristics of the surface ground motion changes in relation to the varying local soil conditions and land topography.

  1. Benzene on Cu(111): II. Molecular assembly due to Lateral van der Waals and Surface-State-Mediated Indirect Interactions

    Science.gov (United States)

    Hyldgaard, Per; Berland, Kristian; Einstein, T. L.

    2010-03-01

    Experiments show that benzene condenses into two different structural phases: a compact and a sparse phase, both of approximately hexagonal symmetry. The vdW-DF calculations demonstrate that the denser benzene-overlayer phase, with lattice constant 6.74 ,s due to direct benzene-benzene vdW attraction. The structure of the second, sparser phase, with lattice spacing 10.24 ,s attributed to the indirect electronic interactions mediated by the well-known metallic surface state on Cu(111). To support this claim, we use a formal Harris-functional approach to evaluate nonperturbatively the asymptotic form of this indirect interaction. Our extended vdW-DF scheme---which combines calculations of molecular physisorption, of direct intermolecular vdW coupling, and of indirect electronic interactions between the molecular adsorbates---accounts well for the structural phases of benzene on Cu(111). Our preliminary vdW-DF study of acene and quinone interactions provides building blocks for modeling of anthraquinone assembly on Cu(111).footnotetextG. Pawin, , L. Bartels, Science 313 (2006) 961

  2. Structural, chemical surface and transport modifications of regenerated cellulose dense membranes due to low-dose {gamma}-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, M.I. [Grupo de Caracterizacion Electrocinetica en Membranas e Interfases, Departamento de Fisica Aplicada I, Facultad de Ciencias, Universidad de Malaga, E-29071 Malaga (Spain); Heredia-Guerrero, J.A., E-mail: jose.alejandro@icmse.csic.es [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, Avda, Americo Vespuccio 49, 41092 Sevilla (Spain); Galan, P. [Grupo de Caracterizacion Electrocinetica en Membranas e Interfases, Departamento de Fisica Aplicada I, Facultad de Ciencias, Universidad de Malaga, E-29071 Malaga (Spain); Benitez, J.J. [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, Avda, Americo Vespuccio 49, 41092 Sevilla (Spain); Benavente, J. [Grupo de Caracterizacion Electrocinetica en Membranas e Interfases, Departamento de Fisica Aplicada I, Facultad de Ciencias, Universidad de Malaga, E-29071 Malaga (Spain)

    2011-04-15

    Research highlights: {yields} Low dose {gamma}-radiation causes slight structural, chemical and morphological changes on regenerated cellulose films. {yields} Induced structural changes increase the fragility of irradiated films. {yields} Structural modifications reduce ion permeability of films. - Abstract: Modifications caused in commercial dense regenerated cellulose (RC) flat membranes by low-dose {gamma}-irradiation (average photons energy of 1.23 MeV) are studied. Slight structural, chemical and morphological surface changes due to irradiation in three films with different RC content were determined by ATR-FTIR, XRD, XPS and AFM. Also, the alteration of their mechanical elasticity has been studied. Modification of membrane performance was determined from solute diffusion coefficient and effective membrane fixed charge concentration obtained from NaCl diffusion measurements. Induced structural changes defining new and effective fracture propagation directions are considered to be responsible for the increase of fragility of irradiated RC membranes. The same structural changes are proposed to explain the reduction of the membrane ion permeability through a mechanism involving either ion pathways elongation and/or blocking.

  3. A Semiautomated Multilayer Picking Algorithm for Ice-sheet Radar Echograms Applied to Ground-Based Near-Surface Data

    Science.gov (United States)

    Onana, Vincent De Paul; Koenig, Lora Suzanne; Ruth, Julia; Studinger, Michael; Harbeck, Jeremy P.

    2014-01-01

    Snow accumulation over an ice sheet is the sole mass input, making it a primary measurement for understanding the past, present, and future mass balance. Near-surface frequency-modulated continuous-wave (FMCW) radars image isochronous firn layers recording accumulation histories. The Semiautomated Multilayer Picking Algorithm (SAMPA) was designed and developed to trace annual accumulation layers in polar firn from both airborne and ground-based radars. The SAMPA algorithm is based on the Radon transform (RT) computed by blocks and angular orientations over a radar echogram. For each echogram's block, the RT maps firn segmented-layer features into peaks, which are picked using amplitude and width threshold parameters of peaks. A backward RT is then computed for each corresponding block, mapping the peaks back into picked segmented-layers. The segmented layers are then connected and smoothed to achieve a final layer pick across the echogram. Once input parameters are trained, SAMPA operates autonomously and can process hundreds of kilometers of radar data picking more than 40 layers. SAMPA final pick results and layer numbering still require a cursory manual adjustment to correct noncontinuous picks, which are likely not annual, and to correct for inconsistency in layer numbering. Despite the manual effort to train and check SAMPA results, it is an efficient tool for picking multiple accumulation layers in polar firn, reducing time over manual digitizing efforts. The trackability of good detected layers is greater than 90%.

  4. Evaluation of the toxicological properties of ground- and surface-water samples from the Aral Sea Basin

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, K. [University of Salzburg, Department of Cell Biology, Hellbrunnerstr. 34, A-5020 Salzburg (Austria); Erdinger, L. [University of Heidelberg, Department for Hygiene and Medical Microbiology, Heidelberg (Germany); Ingel, F. [Russian Academy of Medical Sciences, A.N.Sysin Institute of Human Ecology and Environmental Hygiene, Moscow (Russian Federation); Khussainova, S. [Scientific Center of Pediatrics and Chrildren' s Surgery, Almaty (Kazakhstan); Utegenova, E. [Kazakh Sanitary-Epidemiological Station, Almaty (Kazakhstan); Bresgen, N. [University of Salzburg, Department of Cell Biology, Hellbrunnerstr. 34, A-5020 Salzburg (Austria); Eckl, P.M. [University of Salzburg, Department of Cell Biology, Hellbrunnerstr. 34, A-5020 Salzburg (Austria)]. E-mail: peter.eckl@sbg.ac.at

    2007-03-01

    In order to determine whether there is a potential health risk associated with the water supply in the Aral Sea Basin, ground- and surface-water samples were collected in and around Aralsk and from the Aral Sea in 2002. Water samples from Akchi, a small town close to Almaty, served as controls. Bioassays with different toxicological endpoints were employed to assess the general toxicological status. Additionally, the samples were analysed for microbial contamination. The samples were tested in the primary hepatocyte assay for their potential to induce micronuclei and chromosomal aberrations as cumulative indicators for genotoxicity. In parallel, the effects on cell proliferation evidenced by mitotic index and cytotoxicity such as the appearance of necrotic and apoptotic cells, were determined. Furthermore, samples were examined using the Microtox assay for general toxicity. Chemical analysis according to European regulations was performed and soil and water samples were analysed for DDT and DDE. The results obtained indicated no increased cyto- or genotoxic potential of the water samples, nor levels of DDT or DDE exceeding the thresholds levels suggested by WHO. Our data therefore do not support the hypothesis that the contamination of the drinking water in and around Aralsk is responsible for the health effects previously described such as increased rates of liver disease and in particular liver cancer. Microbiological analysis, however, revealed the presence of contamination in most samples analysed.

  5. [Effects of ground surface mulching in tea garden on soil water and nutrient dynamics and tea plant growth].

    Science.gov (United States)

    Sun, Li-tao; Wang, Yu; Ding, Zhao-tang

    2011-09-01

    Taking a 2-year-old tea garden in Qingdao of Shandong Province as test object, this paper studied the effects of different mulching modes on the soil water and nutrient dynamics and tea plant growth. Four treatments were installed, i.e., no mulching (CK), straw mulching (T1), plastic film mulching (T2), and straw plus plastic film mulching (T3). Comparing with CK, mulching could keep the soil water content at a higher level, and enhance the water use efficiency. In treatments T1 and T3, the tea growth water use efficiency and yield water use efficiency increased by 43%-48% and 7%-13%, respectively, compared with CK. Also in treatments T1 and T3, the contents of soil organic matter, available-N, nitrate-N, and ammonium-N increased significantly, with the soil fertility improved, and the leaf nitrate-N content and nitrate reductase activity increased, which promoted the tea growth and yield (12%-13% higher than CK) and made the peak period of bud growth appeared earlier. Considering the tea growth and yield, water and nutrient use efficiency, environment safety and economic benefit, straw mulching could be an effective ground surface mulching mode for young tea garden.

  6. Evaluation of a multi-modal grounded theory approach to explore patients’ daily coping with breathlessness due to chronic obstructive pulmonary disease

    DEFF Research Database (Denmark)

    Bastrup, Lene; Dahl, Ronald; Pedersen, Preben Ulrich

    2013-01-01

    Conventional methods have not yet succeeded in capturing the complexity of how people with chronic obstructive pulmonary disease (COPD) cope with breathlessness during daily living. We used a multi-modal grounded theory (GT) approach to investigate coping. In this paper, we describe and evaluate ...... the potential to generate new knowledge and may become an important methodological contribution towards understanding the multidimensionality of coping with breathlessness.......; and be ethically justifiable. The approach should also be consistent with the GT methodology of generating a theory. Striving to develop and perfect the multi-modal GT approach was time-consuming. Apart from this practical challenge, the multimodal GT approach met all evaluation criteria. This approach has...... the participants’ ability to remember and narrate how they cope with breathlessness; capture the multidimensional aspects involved in coping with breathlessness; encompass tools for collecting both qualitative and quantitative data, providing the opportunity to generate, synchronize, and combine data...

  7. The effects of nutrient losses from agriculture on ground and surface water quality: the position of science in developing indicators for regulation

    NARCIS (Netherlands)

    Schröder, J.J.; Scholefield, D.; Cabral, F.; Hofmans, G.

    2004-01-01

    The magnitude of current nutrient losses from agriculture to ground and surface water calls for effective environmental policy, including the use of regulation. Nutrient loss is experienced in many countries despite differences in the organisation and intensity of agricultural production. However, a

  8. Validation of the Cooray‐Rubinstein (C‐R) formula for a rough ground surface by using three‐dimensional (3‐D) FDTD

    National Research Council Canada - National Science Library

    Li, Dongshuai; Zhang, Qilin; Liu, Tao; Wang, Zhenhui

    2013-01-01

    In this paper, we have extended the Cooray‐Rubinstein (C‐R) approximate formula into the fractal rough ground surface and then validate its accuracy by using three‐dimensional (3‐D) finite‐difference time‐domain (FDTD...

  9. Results of soil, ground-water, surface-water, and streambed-sediment sampling at Air Force Plane 85, Columbus, Ohio, 1996

    Science.gov (United States)

    Parnell, J.M.

    1997-01-01

    The U.S. Geological Survey (USGS), in cooperation with Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, prepared the Surface- and Ground- Water Monitoring Work Plan for Air Force Plant 85 (AFP 85 or Plant), Columbus, Ohio, under the Air Force Installation Restoration Program to characterize any ground-water, surface-water, and soil contamination that may exist at AFP 85. The USGS began the study in November 1996. The Plant was divided into nine sampling areas, which included some previously investi gated study sites. The investigation activities included the collection and presentation of data taken during drilling and water-quality sampling. Data collection focused on the saturated and unsatur ated zones and surface water. Twenty-three soil borings were completed. Ten monitoring wells (six existing wells and four newly constructed monitoring wells) were selected for water-quality sam pling. Surface-water and streambed-sediment sampling locations were chosen to monitor flow onto and off of the Plant. Seven sites were sampled for both surface-water and streambed-sediment quality. This report presents data on the selected inorganic and organic constituents in soil, ground water, surface water, and streambed sediments at AFP 85. The methods of data collection and anal ysis also are included. Knowledge of the geologic and hydrologic setting could aid Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, and its governing regulatory agencies in future remediation studies.

  10. Transport of a nematicide in surface and ground waters in a farmed tropical catchment with volcanic substratum

    Science.gov (United States)

    Charlier, J.-B.; Cattan, P.; Voltz, M.; Moussa, R.

    2009-04-01

    Assessment of water-pollution risks in agricultural regions requires studying pesticide transport processes in soil and water compartments at the catchment scale. In tropical regions, banana (Musa spp.) plantations are located in zones with abundant rainfalls and soils with high infiltration rates, which lead to washout and leaching of soil-applied pesticides, causing severe diffuse pollution of water resources. The aim of this paper is to determine how the nematicide cadusafos [S,S-di-sec-butyl O-ethyl phosphorodithioate], used in banana plantations, contaminates water and soils at the two scales of subcatchment and catchment. The study site was a small banana-growing catchment on the tropical volcanic island of Guadeloupe in the Caribbean (FWI). The catchment is located in pedoclimatic conditions where rainfall is abundant (> 4000 mm/year), and soil permeable (saturated hydraulic conductivity of Andosol Ks > 30 mm/h). Two campaigns of nematicide application were conducted, one in 2003 over 40% of the catchment and one in 2006 over 12%. For 100 days after application, we monitored the surface water and groundwater flows and the cadusafos concentrations in the soil and in surface and ground waters in a 2400 m² subcatchment and a 17.8 ha catchment. The results show that at the subcatchment scale the high retention in the A horizon of the soil limited the transport of cadusafos by runoff, whereas the lower retention of the molecule in the B horizon favoured percolation towards the shallow groundwater. The contamination levels of surface water, as well as shallow and deep groundwaters, reflected the geological structure of the Féfé catchment: i.e. a shallow aquifer in the most recent volcanic deposits that is rapidly exposed to pollution and a deeper aquifer that is relatively protected from the pollution coming from the treated fields. Comparing the losses of cadusafos at the subcatchment and at the catchment scales revealed that the nematicide re-infiltrated in

  11. Rapid detection and characterization of surface CO2 leakage through the real-time measurement of δ13C signatures in CO2 flux from the ground

    Science.gov (United States)

    Krevor, Samuel; Benson, Sally; Rella, Chris; Perrin, Jean-Christophe; Esposito, Ariel; Crosson, Eric

    2010-05-01

    The surface monitoring of CO2 over geologic sequestration sites will be an essential tool in the monitoring and verification of sequestration projects. Surface monitoring is the only tool that currently provides the opportunity to detect and quantify leakages on the order of 1000 tons/year CO2. Near-surface detection and quantification can be made complicated, however, due to large temporal and spatial variations in natural background CO2 fluxes from biological processes. In addition, current surface monitoring technologies, such as the use of IR spectroscopy in eddy covariance towers and aerial surveys, radioactive or noble gas isotopic tracers, and flux chamber gas measurements can generally accomplish one or two of the necessary tasks of leak detection, identification, and quantification, at both large spatial scales and high spatial resolution. It would be useful, however, to combine the utility of these technologies so that a much simplified surface monitoring program can be deployed. Carbon isotopes of CO2 provide an opportunity to distinguish between natural biogenic CO2 fluxes from the ground and CO2 leaking from a sequestration reservoir that has ultimate origins in a process giving it a distinct isotopic signature such as natural gas processing. Until recently, measuring isotopic compositions of gases was a time-consuming and expensive process utilizing mass-spectrometry, not practical for deployment in a high-resolution survey of a potential leakage site at the surface. Recent developments in commercially available instruments utilizing wavelength scanned cavity ringdown spectroscopy (WS-CRDS) and Fourier transform infrared spectroscopy (FT-IR) have made it possible to rapidly measure the isotopic composition of gases including the 13C and 12C isotopic composition of CO2 in a field setting. A portable stable carbon isotope ratio analyzer for carbon dioxide, based on wavelength scanned cavity ringdown spectroscopy, has been used to rapidly detect and

  12. Challenges related to flotation cleaning of oil shales. Issues due to compositional and surface features and post-grinding surface behavior

    Directory of Open Access Journals (Sweden)

    Altun N. Emre

    2016-01-01

    Full Text Available Oil shale is an important energy resource alternative. Despite its recognition as an unconventional oil source, oil shale is also considered as an important solid fossil fuel alternative to coal and lignites due to the solid form and remarkable extent of organic content. Utilization possibilites, similar to coal and lignites, have been considered in the past decades and direct use of oil shales in thermal power production has been possible in countries like Estonia and China. In the perspective of utilization of oil shales in a similar manner to coal and lignites, problems and restrictions related to the inorganic ash-making and potentially pollutant constituents are applied. In this respect, cleaning of this important energy source through mineral processing methods, particularly by flotation, is an outstanding option. However, on the basis of unique features and distinctive characteristics, treatment of oil shales like a type of coal is a big perception and may be highly misleading. This paper discusses specific challenges regarding flotation behavior of oil shales with reference to the surface characteristics and behavior of oil shale entities – probably the most important aspect that determines the efficiency and success of the flotation based cleaning process.

  13. Surface- and ground-water relations on the Portneuf river, and temporal changes in ground-water levels in the Portneuf Valley, Caribou and Bannock Counties, Idaho, 2001-02

    Science.gov (United States)

    Barton, Gary J.

    2004-01-01

    The State of Idaho and local water users are concerned that streamflow depletion in the Portneuf River in Caribou and Bannock Counties is linked to ground-water withdrawals for irrigated agriculture. A year-long field study during 2001 02 that focused on monitoring surface- and ground-water relations was conducted, in cooperation with the Idaho Department of Water Resources, to address some of the water-user concerns. The study area comprised a 10.2-mile reach of the Portneuf River downstream from the Chesterfield Reservoir in the broad Portneuf Valley (Portneuf River Valley reach) and a 20-mile reach of the Portneuf River in a narrow valley downstream from the Portneuf Valley (Pebble-Topaz reach). During the field study, the surface- and ground-water relations were dynamic. A losing river reach was delineated in the middle of the Portneuf River Valley reach, centered approximately 7.2 miles downstream from Chesterfield Reservoir. Two seepage studies conducted in the Portneuf Valley during regulated high flows showed that the length of the losing river reach increased from 2.6 to nearly 6 miles as the irrigation season progressed.Surface- and ground-water relations in the Portneuf Valley also were characterized from an analysis of specific conductance and temperature measurements. In a gaining reach, stratification of specific conductance and temperature across the channel of the Portneuf River was an indicator of ground water seeping into the river.An evolving method of using heat as a tracer to monitor surface- and ground-water relations was successfully conducted with thermistor arrays at four locations. Heat tracing monitored a gaining reach, where ground water was seeping into the river, and monitored a losing reach, where surface water was seeping down through the riverbed (also referred to as a conveyance loss), at two locations.Conveyance losses in the Portneuf River Valley reach were greatest, about 20 cubic feet per second, during the mid-summer regulated

  14. Dissected Mantle Terrain on Mars: Formation Mechanisms and the Implications for Mid- latitude Near-surface Ground Ice

    Science.gov (United States)

    Searls, M. L.; Mellon, M. T.

    2008-12-01

    Determining the present and past distribution of surface and subsurface ice on Mars is critical for understanding the volatile inventory and climatic history of the planet. An analysis of a latitude-dependent layer of surface material known as the dissected mantle terrain can provide valuable insight into the distribution of ice in the recent past. The dissected mantle terrain is a surface unit that occurs globally in the mid-latitude of Mars. This unit is characterized by a smooth mantle of uniform thickness and albedo that is draped over the existing topography. This smooth mantle is disaggregated and dissected in places resulting in a hummocky pitted appearance. We propose that the mid-latitude dissected terrain results from collapse of a dusty mantle into the void left from desiccation of an underlying ice-rich (pure or dirty ice) layer. During period(s) of high obliquity, it is possible for ice to become stable at lower latitudes. Due to lack of direct solar insolation, surface ice deposits will preferentially accumulate on pole-ward facing slopes first. A mantle of dust and dirt is then deposited on top of these ice-rich deposits. As the climate changes, desiccation of the now buried ice leads to collapse of the overlying dusty layer resulting in a hummocky pitted appearance. This theory is supported by the pole-ward preference for the dissection pits as well an increase in dissection with increasing latitude. A study of the global distribution of the mid-latitude dissected terrain can provide invaluable clues towards unlocking the distribution of ice in the recent past. An analysis of HiRISE images and MOLA data indicate that the distribution of dissection pits varies from one region to the next. Knowing the distribution of ice in conjunction with ice stability modeling can provide a global view of the climate and orbital history of Mars at the time these features formed.

  15. Summertime tropospheric ozone enhancement associated with a cold front passage due to stratosphere-to-troposphere transport and biomass burning: Simultaneous ground-based lidar and airborne measurements

    Science.gov (United States)

    Kuang, Shi; Newchurch, Michael J.; Johnson, Matthew S.; Wang, Lihua; Burris, John; Pierce, Robert B.; Eloranta, Edwin W.; Pollack, Ilana B.; Graus, Martin; de Gouw, Joost; Warneke, Carsten; Ryerson, Thomas B.; Markovic, Milos Z.; Holloway, John S.; Pour-Biazar, Arastoo; Huang, Guanyu; Liu, Xiong; Feng, Nan

    2017-01-01

    Stratosphere-to-troposphere transport (STT) and biomass burning (BB) are two important natural sources for tropospheric ozone that can result in elevated ozone and air-quality episode events. High-resolution observations of multiple related species are critical for complex ozone source attribution. In this article, we present an analysis of coinciding ground-based and airborne observations, including ozone lidar, ozonesonde, high spectral resolution lidar (HSRL), and multiple airborne in situ measurements, made on 28 and 29 June 2013 during the Southeast Nexus field campaign. The ozone lidar and HSRL reveal detailed ozone and aerosol structures as well as the temporal evolution associated with a cold front passage. The observations also captured two enhanced (+30 ppbv) ozone layers in the free troposphere (FT), which were determined from this study to be caused by a mixture of BB and stratospheric sources. The mechanism for this STT is tropopause folding associated with a cutoff upper level low-pressure system according to the analysis of its potential vorticity structure. The depth of the tropopause fold appears to be shallow for this case compared to events observed in other seasons; however, the impact on lower tropospheric ozone was clearly observed. This event suggests that strong STT may occur in the southeast United States during the summer and can potentially impact lower troposphere during these times. Statistical analysis of the airborne observations of trace gases suggests a coincident influence of BB transport in the FT impacting the vertical structure of ozone during this case study.

  16. Changes in albumin/platelet interaction with an artificial surface--due to a antibiotics, pyridoxal phosphate, and lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Chandy, T.; Sharma, C.P.

    1988-04-01

    Protein adsorption and platelet adhesion are two important biological processes arising at the blood prosthetic interface. The effect of certain antibiotics, namely, neomycin, gentamicin, ampicillin, penicillin-G, and streptomycin to modulate the albumin polycarbonate surface interaction was investigated using /sup 125/I albumin from a protein mixture in the presence and absence of isolated calf lymphocytes. This study also demonstrated the changes in platelet-surface adhesion with these antibiotics. The effect of pyridoxal phosphate to modulate the red blood cell-mediated platelet-surface attachment was also attempted. It appears from pyridoxal phosphate studies that pyridoxal 5'-phosphate (PLP) could modify the surface-platelet attachment. It also inhibited the fibrinogen-induced platelet adhesion. It seems, the addition of antibiotics to the polymerprotein system increased the level of surface-bound albumin variably whereas lymphocytes incubated in the medium did not affect the surface-albumin concentration with time course. These antibiotics also inhibited the surface-induced platelet adhesion to variable degrees. Our earlier studies have indicated that certain antibiotics or antiplatelet drugs can inhibit the fibrinogen binding to an artificial surface. Therefore, it may be possible that the enhanced albumin-surface concentration or reduced fibrinogen-surface binding, in the presence of these antibiotics, may itself be one of the parameter for a reduced platelet-surface attachment, which may also improve the blood compatibility of the substrate. A better understanding of the mechanism of antibiotics is needed in in vivo conditions to correlate these findings.

  17. SURFACE GEOPHYSICAL EXPLORATION OF TX-TY TANK FARMS AT THE HANFORD SITE RESULTS OF BACKGROUND CHARACTERIZATION WITH GROUND PENETRATING RADAR

    Energy Technology Data Exchange (ETDEWEB)

    MYERS DA; CUBBAGE R; BRAUCHLA R; O' BRIEN G

    2008-07-24

    Ground penetrating radar surveys of the TX and TY tank farms were performed to identify existing infrastructure in the near surface environment. These surveys were designed to provide background information supporting Surface-to-Surface and Well-to-Well resistivity surveys of Waste Management Area TX-TY. The objective of the preliminary investigation was to collect background characterization information with GPR to understand the spatial distribution of metallic objects that could potentially interfere with the results from high resolution resistivity{trademark} surveys. The results of the background characterization confirm the existence of documented infrastructure, as well as highlight locations of possible additional undocumented subsurface metallic objects.

  18. Deriving Spatio-Temporal Development of Ground Subsidence Due to Subway Construction and Operation in Delta Regions with PS-InSAR Data: A Case Study in Guangzhou, China

    Directory of Open Access Journals (Sweden)

    Huiqiang Wang

    2017-09-01

    Full Text Available Subways have been an important method for relieving traffic pressures in urban areas, but ground subsidence, during construction and operation, can be a serious problem as it may affect the safety of its operation and that of the surrounding buildings. Thus, conducting long-term ground deformation monitoring and modeling for subway networks are essential. Compared with traditional geodetic methods, the Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR technique offers wider coverage and denser measurements along subway lines. In this study, we mapped the surface deformation of the Guangzhou subway network with Advanced Synthetic Aperture Radar (ASAR and Phased Array Type L-band Synthetic Aperture Radar (PALSAR data using the Interferometric Point Target Analysis (IPTA technique. The results indicate that newly excavated tunnels have regional subsidence with an average rate of more than 8 mm/year, as found on Lines Two, Three, Six, and GuangFo (GF. Furthermore, we determined the spatio-temporal subsidence behavior of subways with PALSAR in delta areas using Peck’s formula and the logistic time model. We estimated the tunneling-related parameters in soft soil areas, which had not been previously explored. We examined a section of line GF, as an example, to estimate the ground settlement trough development. The results showed the maximum settlement increased from −5.2 mm to −23.6 mm and its ground loss ratio ranged from 1.5–8.7% between 13 July 2008 and 19 January 2011. In addition, we found that the tunnels in line GF will become stable after a period of about 2300 days in peak subsidence areas. The results show that the proposed approach can help explain the dynamic ground subsidence along a metro line. This study can provide references for urban subway projects in delta areas, and for the risk assessment of nearby buildings and underground pipelines along metro lines.

  19. Ground-penetrating radar (GPR) responses for sub-surface salt contamination and solid waste: modeling and controlled lysimeter studies.

    Science.gov (United States)

    Wijewardana, Y N S; Shilpadi, A T; Mowjood, M I M; Kawamoto, K; Galagedara, L W

    2017-02-01

    The assessment of polluted areas and municipal solid waste (MSW) sites using non-destructive geophysical methods is timely and much needed in the field of environmental monitoring and management. The objectives of this study are (i) to evaluate the ground-penetrating radar (GPR) wave responses as a result of different electrical conductivity (EC) in groundwater and (ii) to conduct MSW stratification using a controlled lysimeter and modeling approach. A GPR wave simulation was carried out using GprMax2D software, and the field test was done on two lysimeters that were filled with sand (Lysimeter-1) and MSW (Lysimeter-2). A Pulse EKKO-Pro GPR system with 200- and 500-MHz center frequency antennae was used to collect GPR field data. Amplitudes of GPR-reflected waves (sub-surface reflectors and water table) were studied under different EC levels injected to the water table. Modeling results revealed that the signal strength of the reflected wave decreases with increasing EC levels and the disappearance of the subsurface reflection and wave amplitude reaching zero at higher EC levels (when EC >0.28 S/m). Further, when the EC level was high, the plume thickness did not have a significant effect on the amplitude of the reflected wave. However, it was also found that reflected signal strength decreases with increasing plume thickness at a given EC level. 2D GPR profile images under wet conditions showed stratification of the waste layers and relative thickness, but it was difficult to resolve the waste layers under dry conditions. These results show that the GPR as a non-destructive method with a relatively larger sample volume can be used to identify highly polluted areas with inorganic contaminants in groundwater and waste stratification. The current methods of MSW dumpsite investigation are tedious, destructive, time consuming, costly, and provide only point-scale measurements. However, further research is needed to verify the results under heterogeneous aquifer

  20. Analysis of isotope element by electrolytic enrichment method for ground water and surface water in Saurashtra region, Gujarat, India

    Directory of Open Access Journals (Sweden)

    Sajal Singh

    2016-12-01

    Full Text Available The present study has been aimed for the assessment of isotope element Tritium (3H. It is a great threat to human health and environment for lengthy duration. The tritium exists in earth in diverse forms such as (1 small amounts of natural tritium are produced by alpha decay of lithium-7, (2 natural atmospheric tritium is also generated by secondary neutron cosmic ray bombardment of nitrogen, (3 atmospheric nuclear bomb testing in the 1950s, although the contribution from nuclear power plants is small. Tritium or 3H is a radioactive isotope of hydrogen with a half-life of 12.32 ± 0.02 years. Water samples from ground water, surface water, and precipitation were collected from different locations in Gujarat area and were analyzed for the same. Distillation of samples was done to reduce the conductivity. Deuterium and Hydrogen were removed by the process of physico-chemical fractionation in the tritium enrichment unit. The basis of physico-chemical fractionation is the difference in the strength of bonds formed by the light vs. the heavier isotope of a given element. A total of 10 cycles (runs were executed using Quintals process. Tritium concentration files were created with help of WinQ and Quick start software in Quintals process (Liquid Scintillation Spectrometer. The concentration of tritium in terms of tritium units (TU of various samples has been determined. The TU values of the samples vary in the range of 0.90–6.62 TU.

  1. GSFLOW - Coupled Ground-Water and Surface-Water Flow Model Based on the Integration of the Precipitation-Runoff Modeling System (PRMS) and the Modular Ground-Water Flow Model (MODFLOW-2005)

    Science.gov (United States)

    Markstrom, Steven L.; Niswonger, Richard G.; Regan, R. Steven; Prudic, David E.; Barlow, Paul M.

    2008-01-01

    The need to assess the effects of variability in climate, biota, geology, and human activities on water availability and flow requires the development of models that couple two or more components of the hydrologic cycle. An integrated hydrologic model called GSFLOW (Ground-water and Surface-water FLOW) was developed to simulate coupled ground-water and surface-water resources. The new model is based on the integration of the U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) and the U.S. Geological Survey Modular Ground-Water Flow Model (MODFLOW). Additional model components were developed, and existing components were modified, to facilitate integration of the models. Methods were developed to route flow among the PRMS Hydrologic Response Units (HRUs) and between the HRUs and the MODFLOW finite-difference cells. This report describes the organization, concepts, design, and mathematical formulation of all GSFLOW model components. An important aspect of the integrated model design is its ability to conserve water mass and to provide comprehensive water budgets for a location of interest. This report includes descriptions of how water budgets are calculated for the integrated model and for individual model components. GSFLOW provides a robust modeling system for simulating flow through the hydrologic cycle, while allowing for future enhancements to incorporate other simulation techniques.

  2. EXAMINATION ABOUT INFLUENCE FOR PRECISION OF 3D IMAGE MEASUREMENT FROM THE GROUND CONTROL POINT MEASUREMENT AND SURFACE MATCHING

    Directory of Open Access Journals (Sweden)

    T. Anai

    2015-05-01

    Full Text Available As the 3D image measurement software is now widely used with the recent development of computer-vision technology, the 3D measurement from the image is now has acquired the application field from desktop objects as wide as the topography survey in large geographical areas. Especially, the orientation, which used to be a complicated process in the heretofore image measurement, can be now performed automatically by simply taking many pictures around the object. And in the case of fully textured object, the 3D measurement of surface features is now done all automatically from the orientated images, and greatly facilitated the acquisition of the dense 3D point cloud from images with high precision. With all this development in the background, in the case of small and the middle size objects, we are now furnishing the all-around 3D measurement by a single digital camera sold on the market. And we have also developed the technology of the topographical measurement with the air-borne images taken by a small UAV [1~5]. In this present study, in the case of the small size objects, we examine the accuracy of surface measurement (Matching by the data of the experiments. And as to the topographic measurement, we examine the influence of GCP distribution on the accuracy by the data of the experiments. Besides, we examined the difference of the analytical results in each of the 3D image measurement software. This document reviews the processing flow of orientation and the 3D measurement of each software and explains the feature of the each software. And as to the verification of the precision of stereo-matching, we measured the test plane and the test sphere of the known form and assessed the result. As to the topography measurement, we used the air-borne image data photographed at the test field in Yadorigi of Matsuda City, Kanagawa Prefecture JAPAN. We have constructed Ground Control Point which measured by RTK-GPS and Total Station. And we show the results

  3. Examination about Influence for Precision of 3d Image Measurement from the Ground Control Point Measurement and Surface Matching

    Science.gov (United States)

    Anai, T.; Kochi, N.; Yamada, M.; Sasaki, T.; Otani, H.; Sasaki, D.; Nishimura, S.; Kimoto, K.; Yasui, N.

    2015-05-01

    As the 3D image measurement software is now widely used with the recent development of computer-vision technology, the 3D measurement from the image is now has acquired the application field from desktop objects as wide as the topography survey in large geographical areas. Especially, the orientation, which used to be a complicated process in the heretofore image measurement, can be now performed automatically by simply taking many pictures around the object. And in the case of fully textured object, the 3D measurement of surface features is now done all automatically from the orientated images, and greatly facilitated the acquisition of the dense 3D point cloud from images with high precision. With all this development in the background, in the case of small and the middle size objects, we are now furnishing the all-around 3D measurement by a single digital camera sold on the market. And we have also developed the technology of the topographical measurement with the air-borne images taken by a small UAV [1~5]. In this present study, in the case of the small size objects, we examine the accuracy of surface measurement (Matching) by the data of the experiments. And as to the topographic measurement, we examine the influence of GCP distribution on the accuracy by the data of the experiments. Besides, we examined the difference of the analytical results in each of the 3D image measurement software. This document reviews the processing flow of orientation and the 3D measurement of each software and explains the feature of the each software. And as to the verification of the precision of stereo-matching, we measured the test plane and the test sphere of the known form and assessed the result. As to the topography measurement, we used the air-borne image data photographed at the test field in Yadorigi of Matsuda City, Kanagawa Prefecture JAPAN. We have constructed Ground Control Point which measured by RTK-GPS and Total Station. And we show the results of analysis made

  4. Elevation change of the Greenland Ice Sheet due to surface mass balance and firn processes, 1960–2014

    OpenAIRE

    2015-01-01

    Observed changes in the surface elevation of the Greenland Ice Sheet are caused by ice dynamics, basal elevation change, basal melt, surface mass balance (SMB) variability, and by compaction of the overlying firn. The last two contributions are quantified here using a firn model that includes compaction, meltwater percolation, and refreezing. The model is forced with surface mass fluxes and temperature from a regional climate model for the period 1960–2014. The model results...

  5. Elevation change of the Greenland Ice Sheet due to surface mass balance and firn processes, 1960-2014

    NARCIS (Netherlands)

    Kuipers Munneke, P.; Ligtenberg, S. R M; Noël, B. P Y; Howat, I. M.; Box, J. E.; Mosley-Thompson, E.; McConnell, J. R.; Steffen, K.; Harper, J. T.; Das, S. B.; Van Den Broeke, M. R.

    2015-01-01

    Observed changes in the surface elevation of the Greenland Ice Sheet are caused by ice dynamics, basal elevation change, basal melt, surface mass balance (SMB) variability, and by compaction of the overlying firn. The last two contributions are quantified here using a firn model that includes compac

  6. Road impacts on the Baca National Wildlife Refuge, Colorado, with emphasis on effects to surface- and shallow ground-water hydrology - A literature review

    Science.gov (United States)

    Andersen, Douglas C.

    2007-01-01

    A review of published research on unpaved road effects on surface-water and shallow ground-water hydrology was undertaken to assist the Baca National Wildlife Refuge, Colorado, in understanding factors potentially influencing refuge ecology. Few studies were found that addressed hydrological effects of roads on a comparable area of shallow slope in a semiarid region. No study dealt with road effects on surface- and ground-water supplies to ephemeral wetlands, which on the refuge are sustained by seasonal snowmelt in neighboring mountains. Road surfaces increase runoff, reduce infiltration, and serve as a sediment source. Roadbeds can interfere with normal surface- and ground-water flows and thereby influence the quantity, timing, and duration of water movement both across landscapes and through the soil. Hydrologic effects can be localized near the road as well as widespread and distant. The number, arrangement, and effectiveness of road-drainage structures (culverts and other devices) largely determine the level of hydrologic alteration produced by a road. Undesirable changes to natural hydrologic patterns can be minimized by considering potential impacts during road design, construction, and maintenance. Road removal as a means to restore desirable hydrologic conditions to landscapes adversely affected by roads has yet to be rigorously evaluated.

  7. Effects of surface applications of biosolids on soil, crops, ground water, and streambed sediment near Deer Trail, Colorado, 1999-2003

    Science.gov (United States)

    Yager, Tracy J.B.; Smith, David B.; Crock, James G.

    2004-01-01

    The U.S. Geological Survey, in cooperation with Metro Wastewater Reclamation District and North Kiowa Bijou Groundwater Management District, studied natural geochemical effects and the effects of biosolids applications to the Metro Wastewater Reclamation District properties near Deer Trail, Colorado, during 1999 through 2003 because of public concern about potential contamination of soil, crops, ground water, and surface water from biosolids applications. Parameters analyzed for each monitoring component included arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, and zinc (the nine trace elements regulated by Colorado for biosolids), gross alpha and gross beta radioactivity, and plutonium, as well as other parameters. Concentrations of the nine regulated trace elements in biosolids were relatively uniform and did not exceed applicable regulatory standards. All plutonium concentrations in biosolids were below the minimum detectable level and were near zero. The most soluble elements in biosolids were arsenic, molybdenum, nickel, phosphorus, and selenium. Elevated concentrations of bismuth, mercury, phosphorus, and silver would be the most likely inorganic biosolids signature to indicate that soil or streambed sediment has been affected by biosolids. Molybdenum and tungsten, and to a lesser degree antimony, cadmium, cobalt, copper, mercury, nickel, phosphorus, and selenium, would be the most likely inorganic 'biosolids signature' to indicate ground water or surface water has been affected by biosolids. Soil data indicate that biosolids have had no measurable effect on the concentration of the constituents monitored. Arsenic concentrations in soil of both Arapahoe and Elbert County monitoring sites (like soil from all parts of Colorado) exceed the Colorado soil remediation objectives and soil cleanup standards, which were determined by back-calculating a soil concentration equivalent to a one-in-a-million cumulative cancer risk. Lead concentrations

  8. Simulating the thermal regime and thaw processes of ice-rich permafrost ground with the land-surface model CryoGrid 3

    Science.gov (United States)

    Westermann, S.; Langer, M.; Boike, J.; Heikenfeld, M.; Peter, M.; Etzelmüller, B.; Krinner, G.

    2016-02-01

    Thawing of permafrost in a warming climate is governed by a complex interplay of different processes of which only conductive heat transfer is taken into account in most model studies. However, observations in many permafrost landscapes demonstrate that lateral and vertical movement of water can have a pronounced influence on the thaw trajectories, creating distinct landforms, such as thermokarst ponds and lakes, even in areas where permafrost is otherwise thermally stable. Novel process parameterizations are required to include such phenomena in future projections of permafrost thaw and subsequent climatic-triggered feedbacks. In this study, we present a new land-surface scheme designed for permafrost applications, CryoGrid 3, which constitutes a flexible platform to explore new parameterizations for a range of permafrost processes. We document the model physics and employed parameterizations for the basis module CryoGrid 3, and compare model results with in situ observations of surface energy balance, surface temperatures, and ground thermal regime from the Samoylov permafrost observatory in NE Siberia. The comparison suggests that CryoGrid 3 can not only model the evolution of the ground thermal regime in the last decade, but also consistently reproduce the chain of energy transfer processes from the atmosphere to the ground. In addition, we demonstrate a simple 1-D parameterization for thaw processes in permafrost areas rich in ground ice, which can phenomenologically reproduce both formation of thermokarst ponds and subsidence of the ground following thawing of ice-rich subsurface layers. Long-term simulation from 1901 to 2100 driven by reanalysis data and climate model output demonstrate that the hydrological regime can both accelerate and delay permafrost thawing. If meltwater from thawed ice-rich layers can drain, the ground subsides, as well as the formation of a talik, are delayed. If the meltwater pools at the surface, a pond is formed that enhances heat

  9. Validation of the Cooray-Rubinstein (C-R) formula for a rough ground surface by using three-dimensional (3-D) FDTD

    Science.gov (United States)

    Li, Dongshuai; Zhang, Qilin; Liu, Tao; Wang, Zhenhui

    2013-11-01

    this paper, we have extended the Cooray-Rubinstein (C-R) approximate formula into the fractal rough ground surface and then validate its accuracy by using three-dimensional (3-D) finite-difference time-domain (FDTD) method at distances of 50 m and 100 m from the lightning channel. The results show that the extended C-R formula has an accepted accuracy for predicting the lightning-radiated horizontal electric field above the fractal rough and conducting ground, and its accuracy increases a little better with the higher of the earth conductivity. For instance, when the conductivity of the rough ground is 0.1 S/m, the error of the peak value predicted by the extended C-R formula is less than about 2.3%, while its error is less than about 6.7% for the conductivity of 0.01 S/m. The rough ground has much effect on the lightning horizontal field, and the initial peak value of the horizontal field obviously decreases with the increase of the root-mean-square height of the rough ground at early times (within several microseconds of the beginning of return stroke).

  10. Study of the Material Transfer Characteristics and Surface Morphology Due to Arc Erosion of PtIr Contact Materials

    Institute of Scientific and Technical Information of China (English)

    WANG Saibei; XIE Ming; YANG Youcai; ZHANG Jiming; CHEN Yongtai; LIU Manmen; YANG Yunfeng; HU Jieqiong; CUI Hao

    2012-01-01

    By means of breaking tests on PtIr contact materials via a JF04C contact material testing machine,it was attempted to elucidate the characterstics of the various surface morphology and material transfer after the arc erosion process caused by break arc.The material transfer characteristics appeared in the experiments were concluded and analyzed.Meanwhile,the morphology of the anode and cathode surface were observed and analyzed by SEM.

  11. Combined land use and climate change impact on Surface and Ground water resources in the Rio Cobre and Great River basin, Jamaica

    Science.gov (United States)

    Setegn, S. G.; Melesse, A. M.; Grey, O.; Webber, D.

    2011-12-01

    Possible adverse impacts of land use and climate change on one hand and population pressure, extended droughts, and environmental degradation on the other hand are major factors limiting water resources availability in the watersheds of Jamaica. The main objective of this study is to analyze the combined impact of land use/ land cover changes as well as climate change on the hydrological processes and water recourses availability in the Rio Cobre and Great River basins. A spatially distributed model SWAT was calibrated and validated in the basin and used for the study of land use and climate change impacts in the watersheds. Different land cover types were tested to analyze its impact on the hydrology of the watershed. The main land cover parameters considered within the Great and Rio Cobre River Watershed includes Agriculture, Tourism, Water, Road Infrastructure, Population, Forestry and land cover Information. The outputs of different Global climate model (GCM) were downscaled to the watershed level and used for assessing the impact of climate change on water resources availability in the area. The analysis of climate change impact on the surface and ground water resources of the basin indicated that the basin will experience a change in water balance due to changes in the major climate variables in the forthcoming decades. The direction of streamflow change follows mainly the direction of changes in rainfall. Many of the models show statistically-significant declines in mean annual streamflow (up to 60% reduction in streamflow) for the different time-periods and scenarios. The combined effect of climate and land-use/land-cover change on the hydrological processes and water recourses variability is an important step to develop sustainable adaptation strategy.

  12. Direct measurements of the energy flux due to chemical reactions at the surface of a silicon sample interacting with a SF6 plasma

    CERN Document Server

    Dussart, Remi; Pichon, Laurianne E; Bedra, Larbi; Semmar, Nadjib; Lefaucheux, Philippe; Mathias, Jacky; Tessier, Yves; 10.1063/1.2995988

    2008-01-01

    Energy exchanges due to chemical reactions between a silicon surface and a SF6 plasma were directly measured using a heat flux microsensor (HFM). The energy flux evolution was compared with those obtained when only few reactions occur at the surface to show the part of chemical reactions. At 800 W, the measured energy flux due to chemical reactions is estimated at about 7 W.cm\\^{-2} against 0.4 W.cm\\^{-2} for ion bombardment and other contributions. Time evolution of the HFM signal is also studied. The molar enthalpy of the reaction giving SiF4 molecules was evaluated and is consistent with values given in literature.

  13. Extremely large non-saturating magnetoresistance and ultrahigh mobility due to topological surface states in metallic Bi2Te3 topological insulator

    OpenAIRE

    Shrestha, K; Chou, M; Graf, D.; Yang, H. D.; Lorenz, B.; Chu, C. W.

    2017-01-01

    Weak antilocalization (WAL) effects in Bi2Te3 single crystals have been investigated at high and low bulk charge carrier concentrations. At low charge carrier density the WAL curves scale with the normal component of the magnetic field, demonstrating the dominance of topological surface states in magnetoconductivity. At high charge carrier density the WAL curves scale with neither the applied field nor its normal component, implying a mixture of bulk and surface conduction. WAL due to topolog...

  14. Advanced ceramics: evaluation of the ground surface Cerâmicas avançadas: avaliação da superfície polida

    Directory of Open Access Journals (Sweden)

    E. C. Bianchi

    2003-09-01

    Full Text Available The aim of this research is to evaluate the influence of grinding and cutting conditions on surfaces of advanced ceramics ground with diamond grinding wheels containing a binding resin bond. The quality surface was analyzed by Scanning Electron Microscopy (SEM.O objetivo desta pesquisa é a avaliação da influência das condições de usinagem na superfície gerada de cerâmicas avançadas retificadas com rebolo diamantado com ligante resinóide. A qualidade superficial foi analisada utilizando-se a Microscopia Eletrônica de Varredura (MEV

  15. Acid neutralization capacity measurements in surface and ground waters in the Upper River Severn, Plynlimon: from hydrograph splitting to water flow pathways

    OpenAIRE

    Neal, C.; Hill, T.; Hill, S.; B. Reynolds

    1997-01-01

    International audience; Acid Neutralization Capacity (ANC) data for ephemeral stream and shallow groundwater for the catchments of the upper River Severn show a highly heterogeneous system of within-catchment water flow pathways and chemical weathering on scales of less than 100m. Ephemeral streams draining permeable soils seem to be supplied mainly from shallow groundwater sources. For these streams, large systematic differences in pH and alkalinity occur due to the variability of the ground...

  16. Electromyographic Activities of Trunk Muscles Due to Different Exercise Intensities during Pulley-based Shoulder Exercises on an Unstable Surface.

    Science.gov (United States)

    Cha, Jae Yun; Shin, Doo Chul; Shin, Seung Ho; Lee, Myung Mo; Lee, Kyoung Jin; Song, Chang Ho

    2014-05-01

    [Purpose] This study examined the relationship between core stability and exercise intensity during a pulley-based shoulder exercise (PBSE) on an unstable support surface. [Subjects] Twenty healthy college students enrolled in this study. [Methods] Surface EMG was carried out in twenty healthy adult men. The electromyographic activities of the rectus abdominis (RA), erector spinae (ES), exercises with 14 kg or 26 kg of resistance and external oblique (EO) muscles during pulley-based shoulder on an unstable support surface (USS) were compared. [Results] The EMG signals of the RA, ES, and EO did not increase with increasing exercise resistance. [Conclusion] Increasing the exercise intensity to increase the core stability during PBSE on a USS may be ineffective.

  17. Free surface due to a flow driven by a rotating disk inside a vertical cylindrical tank: Axisymmetric configuration

    Science.gov (United States)

    Kahouadji, L.; Witkowski, L. Martin

    2014-07-01

    The flow driven by a rotating disk at the bottom of an open fixed cylindrical cavity is studied numerically and experimentally. The steady axisymmetric Navier-Stokes equations projected onto a curvilinear coordinate system are solved by a Newton-Raphson algorithm. The free surface shape is computed by an iterative process in order to satisfy a zero normal stress balance at the interface. In previous studies, regarding the free surface deflection, there is a significant disagreement between a first-order approximation [M. Piva and E. Meiburg, "Steady axisymmetric flow in an open cylindrical container with a partially rotating bottom wall," Phys. Fluids 17, 063603 (2005)] and a full numerical simulation [R. Bouffanais and D. Lo Jacono, "Unsteady transitional swirling flow in the presence of a moving free surface," Phys. Fluids 21, 064107 (2009)]. For a small deflection, the first-order approximation matches with our numerical simulation and for a large deflection a good agreement is found with experimental measurements.

  18. Faraday Rotation Due to Surface States in the Topological Insulator (Bi1-xSbx)2Te3.

    Science.gov (United States)

    Shao, Yinming; Post, Kirk W; Wu, Jhih-Sheng; Dai, Siyuan; Frenzel, Alex J; Richardella, Anthony R; Lee, Joon Sue; Samarth, Nitin; Fogler, Michael M; Balatsky, Alexander V; Kharzeev, Dmitri E; Basov, D N

    2017-02-08

    Using magneto-infrared spectroscopy, we have explored the charge dynamics of (Bi,Sb)2Te3 thin films on InP substrates. From the magneto-transmission data we extracted three distinct cyclotron resonance (CR) energies that are all apparent in the broad band Faraday rotation (FR) spectra. This comprehensive FR-CR data set has allowed us to isolate the response of the bulk states from the intrinsic surface states associated with both the top and bottom surfaces of the film. The FR data uncovered that electron- and hole-type Dirac Fermions reside on opposite surfaces of our films, which paves the way for observing many exotic quantum phenomena in topological insulators.

  19. Strengthened nonlinearity in liquid crystal panel with ZnSe aligning layers due to surface charge accumulation

    Science.gov (United States)

    Zhao, Hua; Xue, Tingyu; Fu, Jiayin; Zhang, Jingwen

    2015-09-01

    With ZnSe thin films as aligning layers in fabricating liquid crystal (LC) panel with pentylcyanobiphenyl doped with C60, the response time in writing holograms was shortened to milliseconds. When two laser beams were overlapped in an LC panel, 2D diffraction patterns were observed, along with exponential gain coefficient highly LC and ZnSe thickness dependent. In addition, energy transferring in subwavelength scale through surface grating was evident. By using a hybrid LC panel, it was found the energy transferring direction was voltage polarity and thickness dependent. Electrostatic modification based surface plasmon polariton excitation was proposed to explain all the findings

  20. The ion chemistry of surface and ground waters in the Taklimakan Desert of Tarim Basin, western China

    Institute of Scientific and Technical Information of China (English)

    ZHU BingQi; YANG XiaoPing

    2007-01-01

    The physio-chemical and chemical features of water in natural conditions are controlled by the weathering of bedrocks, local climate, landforms and other geo-environmental parameters. In order to understand the characteristics of water and the origins of the dissolved loads in the rivers and in the ground waters of the Taklimakan Desert, western China, we studied the ions in the water samples collected from rivers and wells. We collected water samples from four rivers (Keriya River, Cele River, Tumiya River and Yulongkashi River) in the southern desert and ground water samples from many parts of the desert. Major cations and anions were measured using ion-chromatograph and titration with HCl. The total dissolved solids (TDS), pH and conductivity were examined on site by a portable multi-parameter analyzer. The data show that the water in the rivers of southern Taklimakan is still of fresh water quality and slight alkalinity, although the TDS is comparatively higher than that of many other rivers of the world. The ground water is fresh to slightly saline, with TDS a little higher than that of river water in the study area. The concentration of ions is slightly different between the four rivers in the southern Taklimakan. However, the chemistries of ground water in all samples are to a large degree controlled by sodium and chloride. The ions in the ground water are concluded to be mainly from dissolving of evaporites, consistent with the dry climate in the region, whereas the ions in the rivers are mainly from rock weathering. Low-level human imprints are recognized in the ground water samples also.

  1. Hydrology of the Beryl-Enterprise area, Escalante Desert, Utah, with emphasis on ground water; With a section on surface water

    Science.gov (United States)

    Mower, Reed W.; Sandberg, George Woodard

    1982-01-01

    An investigation of the water resources of the Beryl-Enterprise area, Escalante Desert, Utah (pl. 1), was made during 1976-78 as part of a cooperative program with the Utah Department of Natural Resources, Division of Water Rights. Wells were the most important source of water for all purposes in the Beryl-Enterprise area during 1978, but it has not always been so. For nearly a century after the first settlers arrived in about 1860, streams supplied most of the irrigation water and springs supplied much of the water for domestic and stock use. A few shallow wells were dug by the early settlers for domestic and stock water, but the widespread use of ground water did not start until the 1920's when shallow wells were first dug to supply irrigation water. Ground-water withdrawals from wells, principally for irrigation, have increased nearly every year since the 1920's. The quantity withdrawn from wells surpassed that diverted from surface sources during the mid-1940's and was about eight times that amount during the 1970's. As a result, water levels have declined measurably throughout the area resulting in administrative water-rights problems.The primary purpose of this report is to describe the water resources with emphasis on ground water. The surface-water resources are evaluated only as they pertain to the understanding of the ground-water resources. A secondary purpose is to discuss the extent and effects of the development of ground water in order to provide the hydrologic information needed for the orderly and optimum development of the resource and for the effective administration and adjudication of water rights in the area. The hydrologic data on which this report is based are given in a companion report by Mower (1981).

  2. A large 3D physical model: a tool to investigate the consequences of ground movements on the surface structures

    Directory of Open Access Journals (Sweden)

    Hor B.

    2010-06-01

    Full Text Available Soil subsidence of various extend and amplitude can result from the failure of underground cavities, whether natural (for example caused by the dissolution of rocks by underground water flow or man-made (such as mines. The impact of the ground movements on existing structures (houses, buildings, bridges, etc… is generally dramatic. A large small-scale physical model is developed in order to improve our understanding of the behaviour of the building subjected to ground subsidence or the collapse of cavities. We focus on the soil-structure interaction and on the mitigation techniques allowing reducing the vulnerability of the buildings (structures.

  3. Reduction of protein adsorption on silica and polystyrene surfaces due to coating with Complex Coacervate Core Micelles

    NARCIS (Netherlands)

    Brzozowska, A. M.; Hofs, B.; de Keizer, A.; Fokkink, R.; Stuart, Martien A. Cohen; Norde, W.

    2009-01-01

    The reduction of protein adsorption by a polymer brush formed upon adsorption of Complex Coacervate Core Micelles (C3Ms), consisting of a charged copolymer containing a neutral block and an oppositely charged homopolymer, on silica and polystyrene surfaces has been studied in situ using fixed angle

  4. Nonlinear Goos-Haenchen shifts due to surface polariton resonance in Kretschmann configuration with a Kerr-type substrate

    Energy Technology Data Exchange (ETDEWEB)

    Xu Guoding, E-mail: guodingxu@163.co [Department of Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Zang Taocheng; Mao Hongmin; Pan Tao [Department of Physics, Suzhou University of Science and Technology, Suzhou 215009 (China)

    2010-07-26

    As the surface polaritons are excited in Kretschmann configuration with a Kerr-type substrate, the nonlinear Goos-Haenchen (GH) shifts exhibit the optically hysteretic response to the intensity of incident light. For thicker metal films, the GH shifts become very sensitive to the intensity of incident light and the angle of incidence.

  5. New experimental results on the interference of the states of the hydrogen atom due to long-range interaction with the metal surface

    NARCIS (Netherlands)

    Kucheryaev, YA; Pal'chikov, VG; Pchelin, YA; Sokolov, YL; Yakovlev, VP

    2005-01-01

    The interference of the 2P state of the hydrogen atom due to unknown long-range interaction with the metal surface (Sokolov effect) has been studied by an atomic interferometer. In contrast to previous experiments, where an atomic beam passed through slits in metal plates, a beam in the presented ex

  6. Volume changes of Vatnajökull ice cap, Iceland, due to surface mass balance, ice flow, and subglacial melting at geothermal areas

    DEFF Research Database (Denmark)

    Magnússon, Eyjólfur; Björnson, Helgi; Dall, Jørgen

    2005-01-01

    We present observed changes in the geometry of western Vatnajökull over a period of about ten years which are caused by the surface mass balance, ice flow (both during surges and quiescent periods), and basal melting due to geothermal and volcanic activity. Comparison of two digital elevation...

  7. Full-wave modelling of ground-penetrating radars: antenna mutual coupling phenomena and sub-surface scattering processes

    NARCIS (Netherlands)

    Caratelli, D.; Yarovoy, A.

    2011-01-01

    Ground-penetrating radar (GPR) technology finds applications in many areas such as geophysical prospecting, archaeology, civil engineering, environmental engineering, and defence applications as a non-invasive sensing tool [3], [6], [18]. One key component in any GPR system is the receiver/transmitt

  8. Instabilities and bifurcations due to buoyancy in a cylindrical container heated from below with and without a free surface

    Science.gov (United States)

    El Gallaf, Anas; Touihri, Ridha; Henry, Daniel; Ben Hadid, Hamda

    2009-11-01

    Three-dimensional simulations of the buoyant convection in a cylindrical container heated from below are presented. Both the thresholds for the onset of the convection and the nonlinear evolution of this convection are calculated. The simulations concern two configurations: a cavity with a rigid upper surface (Rigid-Rigid case) and a cavity with a non-constrained free surface (Rigid-Free case). The results show a similar variation of the primary thresholds with the aspect ratio for the two configurations. In contrast, the nonlinear evolution of the convection is much changed between the two configurations. In particular, subcritical secondary branches with a very large subcriticity are obtained in the R-F case. To cite this article: A. El Gallaf et al., C. R. Mecanique 337 (2009).

  9. External magnetic field dependent shift of superparamagnetic blocking temperature due to core/surface disordered spin interactions

    Science.gov (United States)

    Lee, Kwan; Jang, Jung-tak; Nakano, Hiroshi; Nakagawa, Shigeki; Paek, Sun Ha; Bae, Seongtae

    2017-02-01

    Although the blocking temperature of superparamagnetic nanoparticles (SPNPs) is crucial for various spintronics and biomedical applications, the precise determination of the blocking temperature is still not clear. Here, we present ‘intrinsic’ and ‘extrinsic’ characteristics of the blocking temperature in SPNP systems. In zero-field-cooled/field-cooled (ZFC-FC) curves, there was no shift of ‘intrinsic blocking temperature’ at different applied external (excitation) magnetic fields. However, ‘extrinsic blocking temperature’ shift is clearly dependent on the external (excitation) magnetic field. According to our newly proposed physical model, the ‘intermediate spin layer’ located between the core and surface disordered spin layers is primarily responsible for the physical nature of the shift of extrinsic blocking temperature. Our new findings offer possibilities for characterizing the thermally induced physical properties of SPNPs. Furthermore, these findings provide a new empirical approach to indirectly estimate the qualitative degree of the disordered surface spin status in SPNPs.

  10. Organochlorine pesticides in surface soils from obsolete pesticide dumping ground in Hyderabad City, Pakistan: contamination levels and their potential for air-soil exchange.

    Science.gov (United States)

    Alamdar, Ambreen; Syed, Jabir Hussain; Malik, Riffat Naseem; Katsoyiannis, Athanasios; Liu, Junwen; Li, Jun; Zhang, Gan; Jones, Kevin C

    2014-02-01

    This study was conducted to examine organochlorine pesticides (OCPs) contamination levels in the surface soil and air samples together with air-soil exchange fluxes at an obsolete pesticide dumping ground and the associated areas from Hyderabad City, Pakistan. Among all the sampling sites, concentrations of OCPs in the soil and air samples were found highest in obsolete pesticide dumping ground, whereas dominant contaminants were dichlorodiphenyltrichloroethane (DDTs) (soil: 77-212,200 ng g(-1); air: 90,700 pg m(-3)) and hexachlorocyclohexane (HCHs) (soil: 43-4,090 ng g(-1); air: 97,400 pg m(-3)) followed by chlordane, heptachlor and hexachlorobenzene (HCB). OCPs diagnostic indicative ratios reflect historical use as well as fresh input in the study area. Moreover, the air and soil fugacity ratios (0.9-1.0) at the dumping ground reflecting a tendency towards net volatilization of OCPs, while at the other sampling sites, the fugacity ratios indicate in some cases deposition and in other cases volatilization. Elevated concentrations of DDTs and HCHs at pesticide dumping ground and its surroundings pose potential exposure risk to biological organisms, to the safety of agricultural products and to the human health. Our study thus emphasizes the need of spatio-temporal monitoring of OCPs at local and regional scale to assess and remediate the future adverse implications.

  11. Investigations of surface characterization of silicone rubber due to tracking phenomena under a.c. and d.c. voltages

    Indian Academy of Sciences (India)

    Uma Maheswar Rao; S S M S Abdul Majeed; C Venkataseshaiah; R Sarathi

    2002-11-01

    In the present work, tracking phenomena has been studied with silicone rubber material under the a.c. and d.c. voltages following IEC-587 standards. The surface condition of the tracked zone was analysed using wide angle X-ray diffraction (WAXD) and thermogravimetric differential thermal analysis (TG–DTA) studies. The tracking time was different for a.c. and d.c. voltages.

  12. Temperature-dependent surface modification of Ta due to high-flux, low-energy He+ ion irradiation

    Science.gov (United States)

    Novakowski, T. J.; Tripathi, J. K.; Hassanein, A.

    2015-12-01

    This work examines the response of Tantalum (Ta) as a potential candidate for plasma-facing components (PFCs) in future nuclear fusion reactors. Tantalum samples were exposed to high-flux, low-energy He+ ion irradiation at different temperatures in the range of 823-1223 K. The samples were irradiated at normal incidence with 100 eV He+ ions at constant flux of 1.2 × 1021 ions m-2 s-1 to a total fluence of 4.3 × 1024 ions m-2. An additional Ta sample was also irradiated at 1023 K using a higher ion fluence of 1.7 × 1025 ions m-2 (at the same flux of 1.2 × 1021 ions m-2 s-1), to confirm the possibility of fuzz formation at higher fluence. This higher fluence was chosen to roughly correspond to the lower fluence threshold of fuzz formation in Tungsten (W). Surface morphology was characterized with a combination of field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). These results demonstrate that the main mode of surface damage is pinholes with an average size of ∼70 nm2 for all temperatures. However, significantly larger pinholes are observed at elevated temperatures (1123 and 1223 K) resulting from the agglomeration of smaller pinholes. Ex situ X-ray photoelectron spectroscopy (XPS) provides information about the oxidation characteristics of irradiated surfaces, showing minimal exfoliation of the irradiated Ta surface. Additionally, optical reflectivity measurements are performed to further characterize radiation damage on Ta samples, showing gradual reductions in the optical reflectivity as a function of temperature.

  13. Quantum critical point due to nested Fermi surface: damping of quasi-particles, resistivity and Hall effect

    Energy Technology Data Exchange (ETDEWEB)

    Schlottmann, P. [Department of Physics, Florida State University, MC 4350-309 Keene Building, Tallahassee, FL 32306 (United States)]. E-mail: schlottm@martech.fsu.edu

    2004-12-31

    The nesting of the Fermi surfaces of an electron pocket and a hole pocket separated by a wave vector Q and the interaction between electrons gives rise to spin- and charge-density waves. The order can gradually be suppressed by mismatching the nesting and a quantum critical point is obtained as the critical temperature tends to zero. We calculate the quasi-particle damping close to the quantum critical point and discuss its consequences on the resistivity and Hall effect.

  14. Nanostructures on GaAs surfaces due to 60 keV Ar{sup +}-ion beam sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Venugopal, V., E-mail: vinay.venu@gmail.com [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India); Division of Physics, School of Advanced Sciences, VIT University, Chennai Campus, Chennai 600 048 (India); Garg, Sandeep Kumar; Basu, Tanmoy [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India); Sinha, Om Prakash [Amity Institute of Nanotechnology, Amity University, Noida 201 303 (India); Kanjilal, D. [Inter-Univeristy Accelerator Center, Aruna Asaf Ali Marg, Delhi 110 067 (India); Bhattacharyya, S.R. [Saha Institute of Nuclear Physics, Kolkata 700 064 (India); Som, T. [Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005 (India)

    2012-02-15

    The effect of 60 keV Ar{sup +}-ion beam sputtering on the surface topography of p-type GaAs(1 0 0) was investigated by varying angle of incidence of the ion (060 Degree-Sign ) with respect to substrate normal and the ion fluence (2 Multiplication-Sign 10{sup 17}3 Multiplication-Sign 10{sup 18} ions/cm{sup 2}) at an ion flux of 3.75 Multiplication-Sign 10{sup 13} ions/cm{sup 2}-s. For normal incidence and at a fluence of 2 Multiplication-Sign 10{sup 17} ions/cm{sup 2}, holes and islands are observed with the former having an average size and density of 31 nm and 4.9 Multiplication-Sign 10{sup 9} holes/cm{sup 2}, respectively. For 30 Degree-Sign and 45 Degree-Sign off-normal incidence, in general, a smooth surface appears which is unaffected by increase of fluence. At 60 Degree-Sign off-normal incidence dots are observed while for the highest fluence of 3 Multiplication-Sign 10{sup 18} ions/cm{sup 2} early stage of ripple formation along with dots is observed with amplitude of 4 nm. The applicability and limitations of the existing theories of ion induced pattern formation to account for the observed surface topographies are discussed.

  15. Comparison of pulse height spectra on CsI(T1)/PIN photodiode radiation detector due to surface encapsulant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han Soo; Ha, Jang Ho; Jeong, Man Hee; Kim, Young Soo; Kim, Dong Jin; Cho, Woo Jin; Choi, Hyo Jeong [Korea Atomic Energy Research Institute, Seoul (Korea, Republic of); Cho, Seung Yeon [Environmental Health Center, Yonsei University, Seoul (Korea, Republic of)

    2014-04-15

    Scintillation crystal converts the energy deposited by an X-ray or gamma ray to light. Usually this scintillation light is collected, converted to electrons and amplified by an photomultiplier tube (PMT). The PMT has the drawbacks of being bulky and requiring a high voltage (HV) to operate it. This scinitllation light can also be collected in a solid state photo-detector, such as a silicon PIN photodiode and an avanlanche photodiode. PIN photodiode, which have 10 mm X 10 mm{sup 2} active area, were fabricated with anti-reflective coating and match with CsI(Tl) scintillator. In this study, radiation reasonabilities were compared with and without surface encapsulant epoxy. Silicon PIN Photodiodes were fabricated with AR coating. To match with CsI(Tl) scintillator, surface encapsulant was applied on the PIN photodiodes. Leakage currents for all the PIN photodiodes show several nA up to 100 V. The pulse height spectra and comparison of the CsI(Tl)PIN photodiode in case of surface encapsulation on PIN photodiode will be presented at the conference.

  16. Error in Radar-Derived Soil Moisture due to Roughness Parameterization: An Analysis Based on Synthetical Surface Profiles

    Directory of Open Access Journals (Sweden)

    Bernard De Baets

    2009-02-01

    Full Text Available In the past decades, many studies on soil moisture retrieval from SAR demonstrated a poor correlation between the top layer soil moisture content and observed backscatter coefficients, which mainly has been attributed to difficulties involved in the parameterization of surface roughness. The present paper describes a theoretical study, performed on synthetical surface profiles, which investigates how errors on roughness parameters are introduced by standard measurement techniques, and how they will propagate through the commonly used Integral Equation Model (IEM into a corresponding soil moisture retrieval error for some of the currently most used SAR configurations. Key aspects influencing the error on the roughness parameterization and consequently on soil moisture retrieval are: the length of the surface profile, the number of profile measurements, the horizontal and vertical accuracy of profile measurements and the removal of trends along profiles. Moreover, it is found that soil moisture retrieval with C-band configuration generally is less sensitive to inaccuracies in roughness parameterization than retrieval with L-band configuration.

  17. Charged plate in asymmetric electrolytes: One-loop renormalization of surface charge density and Debye length due to ionic correlations

    Science.gov (United States)

    Ding, Mingnan; Lu, Bing-Sui; Xing, Xiangjun

    2016-10-01

    Self-consistent field theory (SCFT) is used to study the mean potential near a charged plate inside a m :-n electrolyte. A perturbation series is developed in terms of g =4 π κ b , where b a n d 1 /κ are Bjerrum length and bare Debye length, respectively. To the zeroth order, we obtain the nonlinear Poisson-Boltzmann theory. For asymmetric electrolytes (m ≠n ), the first order (one-loop) correction to mean potential contains a secular term, which indicates the breakdown of the regular perturbation method. Using a renormalizaton group transformation, we remove the secular term and obtain a globally well-behaved one-loop approximation with a renormalized Debye length and a renormalized surface charge density. Furthermore, we find that if the counterions are multivalent, the surface charge density is renormalized substantially downwards and may undergo a change of sign, if the bare surface charge density is sufficiently large. Our results agrees with large MC simulation even when the density of electrolytes is relatively high.

  18. Temporal Monitoring of the Soil Freeze-Thaw Cycles over a Snow-Covered Surface by Using Air-Launched Ground-Penetrating Radar

    KAUST Repository

    Jadoon, Khan

    2015-09-18

    We tested an off-ground ground-penetrating radar (GPR) system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to filter antenna and back scattered effects from the raw GPR data. Near the GPR setup, sensors were installed in the soil to monitor the dynamics of soil temperature and dielectric permittivity at different depths. The soil permittivity was retrieved via inversion of time domain GPR data focused on the surface reflection. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and dielectric permittivity measurements. In particular, five freeze and thaw events were clearly detectable, indicating that the GPR signals respond to the contrast between the dielectric permittivity of frozen and thawed soil. The GPR-derived permittivity was in good agreement with sensor observations. Overall, the off-ground nature of the GPR system permits non-invasive time-lapse observation of the soil freeze-thaw dynamics without disturbing the structure of the snow cover. The proposed method shows promise for the real-time mapping and monitoring of the shallow frozen layer at the field scale.

  19. Temporal Monitoring of the Soil Freeze-Thaw Cycles over a Snow-Covered Surface by Using Air-Launched Ground-Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Khan Zaib Jadoon

    2015-09-01

    Full Text Available We tested an off-ground ground-penetrating radar (GPR system at a fixed location over a bare agricultural field to monitor the soil freeze-thaw cycles over a snow-covered surface. The GPR system consisted of a monostatic horn antenna combined with a vector network analyzer, providing an ultra-wideband stepped-frequency continuous-wave radar. An antenna calibration experiment was performed to filter antenna and back scattered effects from the raw GPR data. Near the GPR setup, sensors were installed in the soil to monitor the dynamics of soil temperature and dielectric permittivity at different depths. The soil permittivity was retrieved via inversion of time domain GPR data focused on the surface reflection. Significant effects of soil dynamics were observed in the time-lapse GPR, temperature and dielectric permittivity measurements. In particular, five freeze and thaw events were clearly detectable, indicating that the GPR signals respond to the contrast between the dielectric permittivity of frozen and thawed soil. The GPR-derived permittivity was in good agreement with sensor observations. Overall, the off-ground nature of the GPR system permits non-invasive time-lapse observation of the soil freeze-thaw dynamics without disturbing the structure of the snow cover. The proposed method shows promise for the real-time mapping and monitoring of the shallow frozen layer at the field scale.

  20. Surface and sub-surface anatomy of the landscape: integrating Unmanned Aerial Vehicle Structure from Motion (UAV-SfM) and Ground Penetrating Radar (GRP) to investigate sedimentary features in the field. - an example from NW Australia

    Science.gov (United States)

    Callow, Nik; Leopold, Matthias; May, Simon Matthias

    2015-04-01

    Geomorphology is confronted by the challenge of reconstructing landscape features at appropriate scales, resolution and accuracy, that allows meaningful analysis of environmental processes and their implications. Field geomorphology offers a discrete snapshot (i.e. one or two field campaigns) to reconstruct how features have changed, evolved or responded over time. We explore the application of an emerging photogrammetry technique called Structure-from-Motion (SfM), which uses multiple photographs of the same feature (but taken at different locations) to create high-accuracy three-dimensional models of surface of sedimentary fans formed by extreme wave events. This approach is complimented by investigation of the sub-surface morphology using Ground Penetrating Radar (GPR). Using an UAV "octocopter", we captured 1208 photos with a DSLR camera (Canon EoS-M) at the height of 50m with a ground pixel resolution of 9mm, above a cyclone wash-over fan in the Exmouth Gulf (Western Australia) that measured about 500m inland by 300m wide. Based on 38 ground control point targets (with between 4 and 45 individual photographs per target) the SfM surface had an absolute total (XYZ) accuracy of 51mm (39mm X, 29mm Y and 14mm Y), based on RTK-DGPS surveying from a local ground reference station (with an absolute AUSPOS accuracy of 57mm X, 6mm Y, 50mm Z to AHD) and an overall relative point accuracy of 7mm. A sparse point cloud of over 5.5 million data points was generated using only points with a reconstruction accuracy of RGB colour of each XYZ pixel) using K-Means clustering within Python. The output was then manually classified into ground and non-ground points, and the geostatistical analyst functionality of ArcGIS used to produce a final bare-earth DEM. This approach has allowed the study team to economically collect an unprecedented high-resolution and accuracy topographic model of this feature to compliment on-ground sediment, geophysics and dating work to analyse the

  1. Contribution of ground surface altitude difference to thermal anomaly detection using satellite images: Application to volcanic/geothermal complexes in the Andes of Central Chile

    Science.gov (United States)

    Gutiérrez, Francisco J.; Lemus, Martín; Parada, Miguel A.; Benavente, Oscar M.; Aguilera, Felipe A.

    2012-09-01

    Detection of thermal anomalies in volcanic-geothermal areas using remote sensing methodologies requires the subtraction of temperatures, not provided by geothermal manifestations (e.g. hot springs, fumaroles, active craters), from satellite image kinetic temperature, which is assumed to correspond to the ground surface temperature. Temperatures that have been subtracted in current models include those derived from the atmospheric transmittance, reflectance of the Earth's surface (albedo), topography effect, thermal inertia and geographic position effect. We propose a model that includes a new parameter (K) that accounts for the variation of temperature with ground surface altitude difference in areas where steep relief exists. The proposed model was developed and applied, using ASTER satellite images, in two Andean volcanic/geothermal complexes (Descabezado Grande-Cerro Azul Volcanic Complex and Planchón-Peteroa-Azufre Volcanic Complex) where field data of atmosphere and ground surface temperature as well as radiation for albedo calibration were obtained in 10 selected sites. The study area was divided into three zones (Northern, Central and Southern zones) where the thermal anomalies were obtained independently. K value calculated for night images of the three zones are better constrained and resulted to be very similar to the Environmental Lapse Rate (ELR) determined for a stable atmosphere (ELR > 7 °C/km). Using the proposed model, numerous thermal anomalies in areas of ≥ 90 m × 90 m were identified that were successfully cross-checked in the field. Night images provide more reliable information for thermal anomaly detection than day images because they record higher temperature contrast between geothermal areas and its surroundings and correspond to more stable atmospheric condition at the time of image acquisition.

  2. Changes in Temperature and Fate of Soil Organic Matter in an Andisol due to Soil Surface Burning

    Science.gov (United States)

    Obuchi, Atsuko; Nishimura, Taku; Mizoguchi, Masaru; Imoto, Hiromi; Miyazaki, Tsuyoshi

    This is a print of a camera-ready Japanese manuscript for the Transactions of JSIDRE. This will provide an example and directions for the layout and font size/style to be used. Please refer to this when preparing the headings, figures/table and text of your manuscript. The manuscript should be submitted on A4 size. Changes in temperature, soil moisture, and carbon and nitrogen contents were measured in Andisol under soil surface burning. Soil samples were packed into an unglazed cylinder of 15 cm inner diameter and 30 cm high. Charcoal was burned for 6 hours on the surface of the soil column. During the burning soil surface temperature rose to between 600-700°C. In initially wet soil, rise in soil temperature was retarded for a while at around 95-100°C. On the other hand, in initially dry Toyoura sand showed more rapid temperature increase without retardation. The temperature retardation in the wet soil could be caused by consumption of latent heat by vaporization of soil water. Rate of proceeding of the 100°C front was proportional to square root of the burning time. This indicates that higher the initial volumetric water content, shallower the depth affected by burning. Soil samples suffered temperature above 500°C still had total carbon and nitrogen contents of over 20 and 1 g kg-1, respectively, whereas the soil that was heated up to over 500°C by muffle furnace contained less than 0.4 and 0.1 g kg-1 of the carbon and nitrogen.

  3. Thermophoresis and Brownian effects on the Blasius flow of a nanofluid due to a curved surface with thermal radiation

    Science.gov (United States)

    Naveed, M.; Abbas, Z.; Sajid, M.

    2016-06-01

    In this analysis, we have discussed the Blasius flow of a nanofluid over a curved surface coiled in a circle of radius R . The physical situation is formulated in a mathematical model using a curvilinear coordinates system. The model is considered for the nanofluid including the effects of Brownian motion and thermophoresis in the presence of thermal radiation. A similarity solution of the developed ordinary differential equations is obtained numerically using the shooting method. The influence of the various involved parameters on the flow phenomena are analyzed through graphs and tables.

  4. Craters in concrete slabs due to detonation – drawbacks of material models with a Mohr-Coulomb yield surface

    Directory of Open Access Journals (Sweden)

    Conrad Markus

    2015-01-01

    Full Text Available Numerical simulations have been performed with a commercial distributed explicit FE-solver and the results have been compared with experiments. High explosive was placed in front of different concrete slabs with the dimension 100 × 100 × 16 cm. Some of the results of the simulations, in particular the profile of the craters, are not in agreement with the test results. Therefore the key characteristics of the constitutive equation based on Mohr-Coulomb yield surfaces and a damage evolution linked to the plastic strain has been reviewed.

  5. HerMES: A DEFICIT IN THE SURFACE BRIGHTNESS OF THE COSMIC INFRARED BACKGROUND DUE TO GALAXY CLUSTER GRAVITATIONAL LENSING

    Energy Technology Data Exchange (ETDEWEB)

    Zemcov, M.; Cooray, A.; Bock, J.; Dowell, C. D.; Nguyen, H. T. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Blain, A. [Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bethermin, M. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Universite Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A.; Glenn, J. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Conversi, L. [Herschel Science Centre, European Space Astronomy Centre, Villanueva de la Canada, E-28691 Madrid (Spain); Farrah, D.; Oliver, S. J.; Roseboom, I. G. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Griffin, M. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Halpern, M.; Marsden, G. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Jullo, E.; Kneib, J.-P. [Aix-Marseille Universite, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR7326, F-13388 Marseille (France); Richard, J., E-mail: zemcov@caltech.edu [Centre de Recherche Astronomique de Lyon, Universite Lyon 1, 9 avenue Charles Andre, F-69230 Saint-Genis Laval (France); and others

    2013-06-01

    We have observed four massive galaxy clusters with the SPIRE instrument on the Herschel Space Observatory and measure a deficit of surface brightness within their central region after removing detected sources. We simulate the effects of instrumental sensitivity and resolution, the source population, and the lensing effect of the clusters to estimate the shape and amplitude of the deficit. The amplitude of the central deficit is a strong function of the surface density and flux distribution of the background sources. We find that for the current best fitting faint end number counts, and excellent lensing models, the most likely amplitude of the central deficit is the full intensity of the cosmic infrared background (CIB). Our measurement leads to a lower limit to the integrated total intensity of the CIB of I{sub 250{mu}m}>0.69{sub -0.03}{sup +0.03}(stat.){sub -0.06}{sup +0.11}(sys.) MJy sr{sup -1}, with more CIB possible from both low-redshift sources and from sources within the target clusters. It should be possible to observe this effect in existing high angular resolution data at other wavelengths where the CIB is bright, which would allow tests of models of the faint source component of the CIB.

  6. HerMES: A Deficit in the Surface Brightness of the Cosmic Infrared Background Due to Galaxy Cluster Gravitational Lensing

    CERN Document Server

    Zemcov, M; Cooray, A; Bethermin, M; Bock, J; Clements, D L; Conley, A; Conversi, L; Dowell, C D; Farrah, D; Glenn, J; Griffin, M; Halpern, M; Jullo, E; Kneib, J -P; Marsden, G; Nguyen, H T; Richard, S J Oliver J; Roseboom, I G; Schulz, B; Scott, Douglas; Shupe, D L; Smith, A J; Valtchanov, I; Viero, M; Wang, L; Wardlow, J

    2013-01-01

    We have observed four massive galaxy clusters with the SPIRE instrument on the Herschel Space Observatory and measure a deficit of surface brightness within their central region after subtracting sources. We simulate the effects of instrumental sensitivity and resolution, the source population, and the lensing effect of the clusters to estimate the shape and amplitude of the deficit. The amplitude of the central deficit is a strong function of the surface density and flux distribution of the background sources. We find that for the current best fitting faint end number counts, and excellent lensing models, the most likely amplitude of the central deficit is the full intensity of the cosmic infrared background (CIB). Our measurement leads to a lower limit to the integrated total intensity of the CIB of I(250 microns) > 0.69_(-0.03)^(+0.03) (stat.)_(-0.06)^(+0.11) (sys.) MJy/sr, with more CIB possible from both low-redshift sources and from sources within the target clusters. It should be possible to observe th...

  7. In situ surface-enhanced Raman spectroscopy effect in zeolite due to Ag2Se quantum dots

    Science.gov (United States)

    Martinez-Nuñez, C. E.; Cortez-Valadez, M.; Delgado-Beleño, Y.; Flores-López, N. S.; Román-Zamorano, J. F.; Flores-Valenzuela, J.; Flores-Acosta, M.

    2017-02-01

    This study shows the presence of surface-enhanced Raman spectroscopy (SERS) effect caused by Ag2Se quantum dots embedded in the zeolite matrix. The quantum dots that were synthesised and stabilised in the matrix of F9-NaX zeolite show a size of 5 nm and a quasi-spherical morphology. The calculated interplanar distances confirm the presence of quantum dots in cubic phase Im-m. We suppose that the in situ SERS effect in the material is caused by chemical-enhancement mechanism (CEM). The density functional theory (DFT) is undertaken to corroborate our hypothesis. The structure H8Si8Al8O12 represents the zeolite cavity unit, and small clusters of (Ag2Se) n represent the quantum dots. Both structures interact in the cavity to obtain the local minimum of the potential energy surface, leading to new molecular orbitals. After the analysis of the predicted Raman spectrum, the Raman bands increase significantly, agreeing with the experimental results at low wavenumbers in F9-NaX zeolite.

  8. Laser-induced damage characteristics in fused silica surface due to mechanical and chemical defects during manufacturing processes

    Science.gov (United States)

    Li, Yaguo; Yuan, Zhigang; Wang, Jian; Xu, Qiao

    2017-06-01

    Mechanical and chemical defects incurred by grinding and polishing as well as post-processing have been recognized as the most influential culprits that hamper the elevation of laser power/energy in high peak power/energy laser systems. In order to find out the causes for limiting the operational power of laser systems, the effects of these defects on laser damage and removal and mitigation of the defects were investigated in detail in the article. Cracks and scratches were created, annealed, etched and damaged so as to reveal the likely effects of mechanical defects on damage and potential techniques to reduce their influence. The results show that HF-based etching can open and smooth cracks/scratches, improving laser-induced damage threshold (LIDT) at scratches by up to >250%. Thermal annealing did heal, to some extent, cracks but the LIDT is little improved. Both HF-etching and leaching proves to be effective in removing metallic contamination during polishing process and handling of optics, which can "contribute" to damage/damage density in fused silica. However, HF-based etching may degrade surface roughness, from 20 nm under some conditions when >20 μm material was etched away while the surface roughness was perceptibly altered by leaching (30 J/cm2 (355 nm @3 ns, beam diameter 400 μm @1/e2), a significant progress.

  9. Ground tests with prototype of CeBr3 active gamma ray spectrometer proposed for future venus surface missions

    Science.gov (United States)

    Litvak, M. L.; Sanin, A. B.; Golovin, D. V.; Jun, I.; Mitrofanov, I. G.; Shvetsov, V. N.; Timoshenko, G. N.; Vostrukhin, A. A.

    2017-03-01

    The results of a series of ground tests with a prototype of an active gamma-ray spectrometer based on a new generation of scintillation crystal (CeBr3) are presented together with a consideration to its applicability to future Venus landing missions. We evaluated the instrument's capability to distinguish the subsurface elemental composition of primary rock forming elements such as O, Na, Mg, Al, Si, K and Fe. Our study uses heritage from previous ground and field tests and applies to the analysis of gamma lines from activation reaction products generated by a pulsed neutron generator. We have estimated that the expected accuracies achieved in this approach could be as high as 1-10% for the particular chemical element being studied.

  10. Challenges related to flotation cleaning of oil shales. Issues due to compositional and surface features and post-grinding surface behavior

    OpenAIRE

    Altun N. Emre

    2016-01-01

    Oil shale is an important energy resource alternative. Despite its recognition as an unconventional oil source, oil shale is also considered as an important solid fossil fuel alternative to coal and lignites due to the solid form and remarkable extent of organic content. Utilization possibilites, similar to coal and lignites, have been considered in the past decades and direct use of oil shales in thermal power production has been possible in countries like Estonia an